Howden GlobalMining Australia

78
ENGINEERING EXCELLENCE ULTIMATE RELIABILITY GLOBAL SOLUTIONS FOR MINING AND PRIMARY PROCESSING www.howden.com

description

Howden Australia

Transcript of Howden GlobalMining Australia

Page 1: Howden GlobalMining Australia

ENGINEERING EXCELLENCEULTIMATE RELIABILITYGLOBAL SOLUTIONS FOR MINING AND PRIMARY PROCESSING

www.howden.com

Page 2: Howden GlobalMining Australia

HOWDEN, A GLOBAL SUPPLIER TO THE RESOURCE INDUSTRY

We engineer and construct large turnkey ventilation, refrigeration and gas cleaning systems, integrate equipment into existing plant, or supply stand-alone units for user-defined duties. With nearly 160 years’ experience it is little wonder that the world’s major commodities producers trust us to design, build, install and commission engineered solutions that offer the user exceptional performance and dependability, even in the harshest operating conditions.

Our success follows from our professional engineers’ enduring quest to design the optimum solution for each customer, supported by a shared worldwide institutional knowledge base that is the

envy of our competitors. We use sophisticated computer software and our international experience to examine multiple solutions for the customer’s application. The best option is selected for each mining or processing requirement, and then designed using sophisticated Computer Aided Design (CAD) programs. Tests with flow modelling software ensure the performance and efficiency of the design is optimised for the task.

Howden products are manufactured in world-class facilities under quality assurance management systems certified to international standards. Our artisans have years’ of experience in fabricating hardware that has stood the test of time at site, where it matters most.

The equipment is installed and commissioned by site service staff led by experienced project managers, and serviced and supported by skilled maintenance engineers. Howden understands the production, efficiency and system availability priorities of the resources industry; we have the intellectual capital to match these requirements, the capacity to build and supply them world-wide and the commitment and passion to support them throughout their extended operational lives.

HOWDEN’S VENTILATION, COOLING, GAS CLEANING EQUIPMENT AND OTHER KNOW-HOW ARE USED TO HELP WREST AND PROCESS PRECIOUS AND BASE METALS, COAL ENERGY AND MINERALS FROM THE WORLD’S MOST DEMANDING MINING ENVIRONMENTS.

Page 3: Howden GlobalMining Australia

1

CONTENTSAPPLICATIONS

Hard Rock Mining 4

Coal Mining 6

Copper Processing 8

Iron Pelletising 10

Mineral Sands 12

Nickel Processing 14

Alumina Production 16

Uranium Processing 18

Base Metals Refining 20

Platinum Extraction and Concentration 22

Gold Concentrating and Refining 24

Potash and Fertiliser 26

PRODUCTS

Heavy Duty Centrifugal Fans 30

Medium Duty Centrifugal Fans 32

Adjustable Pitch Axial Flow Fans 34

Auto Variable Pitch Axial Flow Fans 36

Heavy Duty Mixed Flow Fans 38

Auxiliary and Portable Fans 40

Cooling Fans 42

Electrical, Instrumentation and Control Systems 44

Compressors 46

Attenuators 48

Centrifugal Blowers 50

Hard Ice Plants & Thermal Ice Storage 52

Dust Collection and Flue Gas Cleaning 54

Chillers 56

Portable Cooling Plant 58

Furnaces and Industrial Combustion 60

Furnace Off-gas Recovery Plant 61

Rotary Heat Exchangers 62

Dust Scrubbers 64

SERVICES

Howden Legacy Brands 68

Howden Mining Products Capabilities 70

Turnkey Installations 72

Lifetime Maintenance 74

HOWDEN KNOW HOW

Content for Knowledge and Information Section

Fan Blades 31

Fan Design 33

Fan Laws 35

Fan Power & Speed 37

Fan Choices 39

Fan Stall 41

Fan Noise Levels 43

Fan Systems 45

Compressors 47

Acoustics 49

Compressor Assessment 51

Fan Bids 53

Fan Maintenance 55

Fan Increasing Output 57

Fan Pressure 59

Rotary Air Heater Bids 60

Rotary Air Heaters 63

Rotary Air Heater Elements 65

Page 4: Howden GlobalMining Australia

2

Page 5: Howden GlobalMining Australia

3

APPLICATION OF PRODUCTSFOR ALL MINING AND MINERAL PROCESSING

IN THIS SECTION

Hard Rock Mining 4

Coal Mining 6

Copper Processing 8

Iron Pelletising 10

Mineral Sands 12

Nickel Processing 14

Alumina Production 16

Uranium Processing 18

Base Metals Refining 20

Platinum Extraction and Concentration 22

Gold Concentrating and Refining 24

Potash and Fertiliser 26

Page 6: Howden GlobalMining Australia

4

HARD ROCK MINING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey design, fabrication and installation of main surface fans

• Design and installation of underground booster fans

• Auxiliary fans

• Turnkey mine cooling plant

• Cooling fans for heat exchangers

• Electrical instrumentation and control systems

• Fan noise attenuation

• Methane gas abatement

• Low pressure, high volume rock fans

HARD ROCK MINING PRESENTS ONE OF THE HOTTEST AND MOST DIFFICULT WORKPLACE ENVIRONMENTS IN THE WORLD. HOWDEN TRANSFERS COOLED, FRESH AIR KILOMETRES BENEATH THE SURFACE OF DEEP-LEVEL MINES SO THAT MINING OPERATIONS CAN BE MAINTAINED AND INVESTMENT RETURNS MAXIMISED.

Page 7: Howden GlobalMining Australia

5

APPLICATION OF PRODUCTS

Page 8: Howden GlobalMining Australia

6

HOWDEN HAS A RANGE OF SOLUTIONS AND EQUIPMENT DESIGNED SPECIFICALLY FOR COAL MINERS. A RELIABLE SUPPLY OF FRESH AIR IS SUPPLIED UNDERGROUND AND COAL DUST IS REMOVED FROM THE ATMOSPHERE TO IMPROVE SAFETY AND HEALTH.

COAL MINING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey design, fabrication and installation of main surface fans

• Design and installation of underground booster fans

• Auxiliary fans

• Dust scrubbers

• Dust collectors supplied on a turnkey basis

• Electrical instrumentation and control systems

• Fan noise attenuation

• Portable Cooling Plant

• Methane gas abatement

• Underground Coal Gasification (UCG) Processes

Page 9: Howden GlobalMining Australia

7

APPLICATION OF PRODUCTS

Page 10: Howden GlobalMining Australia

8

COPPER PROCESSING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey axial fan installations

• Turnkey wet dust scrubbing and dry dust collecting

• Efficient, two-stage centrifugal flotation blowers

• Turnkey flue gas cleaning for furnaces

• Turbo and multi-stage centrifugal blowers

• Cooling fans for heat exchangers

• Electrical control and instrumentation systems

• Cooling Plant

• Preheaters

SPECIALISED SYSTEMS AND EQUIPMENT ARE DESIGNED FOR THE COPPER RECOVERY PROCESS, AND ARE SUPPLIED EITHER ON A TURNKEY BASIS OR AS STAND-ALONE SYSTEMS ENGINEERED TO INDIVIDUAL REQUIREMENTS.

Page 11: Howden GlobalMining Australia

9

APPLICATION OF PRODUCTS

Page 12: Howden GlobalMining Australia

10

IRON PELLETISING

OUR EQUIPMENT AND SERVICES INCLUDE

• Design and installation of windbox and recuperator fans, and updraught drying and cooling air fans

• Design and installation of hood and windbox exhaust fans

• Grate drying and grate pre-heat gas fans

• Gas to mill drying fans

• Turnkey wet dust scrubbing and dry dust collecting

• Turnkey flue gas cleaning

• Turnkey fan installations for boiler houses

• Electrical control and instrumentation systems

• Fan noise attenuation

• Furnaces

• Furnace off-gas recovery plant

HOWDEN ENGINEERS SYSTEMS AND PRODUCTS THAT CAN BE EMPLOYED IN THE PROCESSES TO PRODUCE IRON ORE PELLETS, USING TRAVELLING GRATE OR GRATE-KILN PROCESS TECHNOLOGIES. OUR INVOLVEMENT STARTS AT THE CRUSHING AND MILLING STAGE, AND INCLUDES TURNKEY SOLUTIONS AND EQUIPMENT DESIGNED AND MANUFACTURED TO CLIENT SPECIFICATION.

Page 13: Howden GlobalMining Australia

11

APPLICATION OF PRODUCTS

Page 14: Howden GlobalMining Australia

12

MINERAL SANDS

OUR EQUIPMENT AND SERVICES INCLUDE

• Fluidising and combustion air fans

• Calcining kiln induced draft fans

• Multi-stage centrifugal blowers

• Fan noise attenuation

• Turnkey furnace off-gas recovery plant

FOR MINERALS SANDS PROCESS PLANTS HOWDEN ENGINEERS CUSTOMER-SPECIFIED FANS AND ANCILLARY SYSTEMS.

Page 15: Howden GlobalMining Australia

13

APPLICATION OF PRODUCTS

Page 16: Howden GlobalMining Australia

14

NICKEL PROCESSING

OUR EQUIPMENT AND SERVICES INCLUDE

• Design and installation of hot gas fans

• Efficient, two-stage centrifugal flotation blowers

• Turnkey wet dust scrubbing and dry dust collecting

• Turnkey flue gas cleaning

• Cooling fans for heat exchangers

• Electrical instrumentation and control systems

• Fan noise attenuation

SEVERAL DIFFERENT PRODUCTS AND SYSTEMS ARE SUPPLIED FOR USE THROUGHOUT THE NICKEL SMELTING PROCESS. THESE ARE ENGINEERED EITHER ON A TURNKEY BASIS, OR SUPPLIED ACCORDING TO THE UNIQUE SPECIFICATIONS OF EACH CUSTOMER.

Page 17: Howden GlobalMining Australia

15

APPLICATION OF PRODUCTS

Page 18: Howden GlobalMining Australia

16

ALUMINA PRODUCTION

HOWDEN IS EXPERIENCED IN DESIGNING SYSTEMS USED BY THE WORLD’S LEADING ALUMINIUM PRODUCERS WHERE ITS EQUIPMENT IS USED EXTENSIVELY IN THE PROCESS TO CONVERT BAUXITE TO ALUMINA.

OUR EQUIPMENT AND SERVICES INCLUDE

• Design and installation of calciner forced and induced draft fans

• Design and installation of liquor burning induced draft fans

• Turbo and multi-stage centrifugal blowers

• Turnkey wet dust scrubbing and dry dust collecting

• Turnkey flue gas cleaning

• Cooling fans for heat exchangers

• Packaged air heater solutions

• Electrical instrumentation and control systems

• Fan noise attenuation

Page 19: Howden GlobalMining Australia

17

APPLICATION OF PRODUCTS

Page 20: Howden GlobalMining Australia

18

URANIUM PROCESSING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey wet dust scrubbing and dry dust collecting

• Design and installation of calciner fans

• Turnkey flue gas cleaning for furnaces

• Cooling fans for heat exchangers

• Electrical instrumentation and control systems

• Flotation blowers

• Fan noise attenuation

URANIUM PROCESSING IS SUPPORTED THROUGH THE SUPPLY OF SYSTEMS AND CUSTOMER-SPECIFIED EQUIPMENT, STARTING AT CRUSHING AND MILLING AND EXTENDING TO THE PRODUCTION OF YELLOW CAKE.

Page 21: Howden GlobalMining Australia

19

APPLICATION OF PRODUCTS

Page 22: Howden GlobalMining Australia

20

BASE METALS REFINING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey axial fan installations

• Design and installation of hot gas fans

• Turnkey wet dust scrubbing and dry dust collecting

• Turbo and multi-stage centrifugal blowers

• Turnkey flue gas cleaning for furnaces

• Cooling fans for heat exchangers

• Packaged air heater solutions

• Electrical instrumentation and control systems

• Furnaces

A SELECTION OF EQUIPMENT IS SUPPLIED FOR USE ON BASE METALS PROCESSING PLANTS SUCH AS THOSE FOR CHROMIUM, COBALT, LEAD, MAGNESIUM, TIN AND ZINC. ALL SYSTEMS ARE ENGINEERED ACCORDING TO THE CUSTOMER’S SPECIFICATIONS AND OFFERED WITH LONG-TERM MAINTENANCE AND ENGINEERING SUPPORT.

Page 23: Howden GlobalMining Australia

21

APPLICATION OF PRODUCTS

Page 24: Howden GlobalMining Australia

22

PLATINUM EXTRACTION AND CONCENTRATION

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey wet dust scrubbing and dry dust collecting

• Efficient, multi-stage centrifugal flotation blowers

• Air blowers

• Turnkey flue gas cleaning

• Cooling fans for heat exchangers

• Packaged air heater solutions

• Electrical instrumentation and control systems

• Furnace off-gas recovery

• Fan noise attenuation

HOWDEN HAS AN ESTABLISHED REPUTATION FOR SUPPLYING A RANGE OF RELIABLE EQUIPMENT USED DURING THE EXTRACTION AND CONCENTRATION STAGES OF THE PLATINUM RECOVERY PROCESS.

Page 25: Howden GlobalMining Australia

23

APPLICATION OF PRODUCTS

Page 26: Howden GlobalMining Australia

24

GOLD CONCENTRATING AND REFINING

OUR EQUIPMENT AND SERVICES INCLUDE

• Turnkey wet dust scrubbing and dry dust collecting

• Efficient, multi-stage centrifugal flotation blowers

• Cooling fans for heat exchangers

• Electrical control and instrumentation

• Gold room ventilation and gas cleaning

HOWDEN HAS A LONG HISTORY IN GOLD CONCENTRATING AND REFINING, AND IS ABLE TO ADAPT ITS EQUIPMENT AND SYSTEMS INTO A RANGE OF FIT-FOR-PURPOSE SOLUTIONS FOR USE IN DIFFERENT GOLD EXTRACTION PROCESSES.

Page 27: Howden GlobalMining Australia

25

APPLICATION OF PRODUCTS

Page 28: Howden GlobalMining Australia

26

POTASH AND FERTILISER

OUR EQUIPMENT AND SERVICES INCLUDE

• Dust scrubbers and dust collectors supplied on a turnkey basis

• Furnaces

• Combustion air fans

• Design and installation of calciner fans

• Electrical control and instrumentation

• Fan noise attenuation

• Airheaters

• Rotary air-preheaters

HOWDEN SUPPLIES SEVERAL SYSTEMS TO THE POTASH AND FERTILISER INDUSTRIES FOR USE DURING RECOVERY AND PROCESSING. ALL SYSTEMS ARE SUPPLIED TO CUSTOMER SPECIFICATION.

Page 29: Howden GlobalMining Australia

27

APPLICATION OF PRODUCTS

Page 30: Howden GlobalMining Australia

28

Page 31: Howden GlobalMining Australia

29

HOWDEN PRODUCTSAN EXTENSIVE RANGE AND A GLOBAL REACH

IN THIS SECTION

Heavy Duty Centrifugal Fans 30

Medium Duty Centrifugal Fans 32

Adjustable Pitch Axial Flow Fans 34

Auto Variable Pitch Axial Flow Fans 36

Heavy Duty Mixed Flow Fans 38

Auxiliary and Portable Fans 40

Cooling Fans 42

Electrical, Instrumentation and Control Systems 44

Compressors 46

Attenuators 48

Centrifugal Blowers 50

Hard Ice Plants & Thermal Ice Storage 52

Dust Collection and Flue Gas Cleaning 54

Chillers 56

Portable Cooling Plant 58

Furnaces and Industrial Combustion 60

Furnace Off-gas Recovery Plant 61

Rotary Heat Exchangers 62

Dust Scrubbers 64

HOWDEN KNOW HOW

Content for Knowledge and Information Section

Fan Blades 31

Fan Design 33

Fan Laws 35

Fan Power & Speed 37

Fan Choices 39

Fan Stall 41

Fan Noise Levels 43

Fan Systems 45

Compressors 47

Acoustics 49

Compressor Assessment 51

Fan Bids 53

Fan Maintenance 55

Fan Increasing Output 57

Fan Pressure 59

Rotary Air Heater Bids 60

Rotary Air Heaters 63

Rotary Air Heater Elements 65

Page 32: Howden GlobalMining Australia

30

HOWDEN OFFERS A WIDE RANGE OF CUSTOM DESIGNED CENTRIFUGAL FANS TO PRECISELY MEET THE APPLICATION REQUIREMENTS OF THE MOST DEMANDING SPECIFICATIONS, INCLUDING MAIN SURFACE FANS FOR MINES.

Our scope of supply can extend to complete turnkey installations that comprise civil works, high voltage equipment, electrical panels, acoustic components, instrumentation and telemetry.

Various output control methods are offered to provide our customers with flexible and efficient performance. These output control methods include inlet radial vanes, inlet louvre dampers and variable speed drives. In the instances where variable speed drives are required, we can provide a complete fatigue analysis and life estimate.

Proprietary Howden rotor dynamics software allows for the precise calculation of forward whirl and reverse whirl critical speed margins, taking into account the stiffness of every single element in the rotor support system.

In addition to conventional bearing types, we can offer specialised bearing designs such as multi-lobed sleeve or pressure fed sleeve bearings. This enables our designers to optimise the bearing selection for every application. Shaft seals are custom designed to accommodate the most demanding requirements for seal effectiveness, and can include double carbon ring types with air or inert gas sealing and purging. Mechanical type and gas tight water seals can also be provided for hazardous fluid applications.

Impeller designs offered include radial, radial tip, laminar backward curved or inclined, and a range of aerofoil blade types. All blade designs can be fitted with wear protection to suit the application requirements.

Howden centrifugal fans are manufactured using the latest technology and materials to ensure structural integrity and strength, fatigue, corrosion and erosion resistance. All fans are constructed in accordance with the Howden design rules which we have evolved and refined over many decades of industry experience.

Materials ranging from high tensile steel to titanium and duplex stainless steels and composites can be used. Specialised coatings and hardening processes result in fans that are rugged, reliable and efficient.

HEAVY DUTYCENTRIFUGAL FANS

Page 33: Howden GlobalMining Australia

31

BACKWARD CURVED BLADESA highly efficient shape, which is inherently strong and can carry liners if required.

BACKWARD INCLINED BLADESAn efficient and strong shape, which is simpler to manufacture than the backward curved blade, particularly when linered.

AEROFOIL BLADESA highly-efficient design, used primarily for wide impellers with large inlets.

RADIAL BLADESA relatively low efficiency, mechanically-strong design used in high dust environments. The radial blades can carry heavy liners and dust cannot become trapped on the underside of the blade.

BACKWARD INCLINED FORWARD CURVED BLADESThis design combines good efficiency with a resistance to dust fouling the underside of the blade.

HOWDEN KNOW HOW

FAN BLADES

CENTRIFUGAL FAN BLADE TYPESVirtually all Howden centrifugal fans have backward inclined blades as this is inherently the most efficient aerodynamic design. Some are flat and others are curved and the suitability of a particular shape is defined first by the aerodynamic duty and then by the application.

HOWDEN PRODUCTS

Page 34: Howden GlobalMining Australia

32

MEDIUM DUTYCENTRIFUGAL FANS

HOWDEN OFFERS A WIDE RANGE OF CUSTOM ENGINEERED CENTRIFUGAL FANS TO SATISFY THE NEEDS OF A DIVERSE RANGE OF APPLICATIONS.

These fans differ from the heavy duty range in that, being smaller and lighter, they can be pre-engineered, and as such are a more cost effective solution for many mining applications. Our scope of supply can extend to complete turnkey installations that include civil works, high-voltage equipment, electrical panels, acoustic components, instrumentation and telemetry.

Various output control methods are available to achieve flexible and efficient performance. These output control methods include inlet radial vanes, inlet louvre dampers and variable speed fans. For variable speed drives, we can provide a complete fatigue analysis and life assessment.

Bearings are normally rolling element type. Shaft seals are custom designed to accommodate the most demanding requirements for seal effectiveness, and can include double carbon ring types with air or inert gas sealing and purging. Mechanical type and gas tight water seals can also be provided for hazardous fluid applications.

Impeller designs offered include radial, radial tip, laminar backward curved or inclined, and a range of aerofoil blade types.

Howden centrifugal fans are manufactured using the latest technology and materials to ensure structural integrity and strength, and resistance to fatigue, corrosion and erosion. All fans are constructed in accordance with our design rules, which have evolved over many decades of industry experience.

Page 35: Howden GlobalMining Australia

33

UPGRADING FANS – DESIGN CONSIDERATIONSAll fans are designed, manufactured and tested to a standard that achieves the customer’s specification in terms of pressure, volume, absorbed power etc. However during the lifetime of the fan the requirements sometimes change. To upgrade fans, the following is relevant:

EROSIONConsider change to liner or hard-surfacing if erosion is excessive

CORROSIONAn alternative impeller material will improve availability if corrosion is excessive

FOULINGExcessive fouling will unbalance the impeller leading to excessive vibration. Different blade shapes and impeller types offer a solution to fouling.

BEARINGSConsidering a change to sleeve bearings is worth noting if there is excessive maintenance on existing roller element bearings.

UPGRADING FANSREDUCING NOISEIdentifying the source of noise is a complex task in a real plant environment. Measurements may be affected by other noise sources or by reflections from nearby surfaces. Experience counts a great deal in making noise measurements. If a fan has been identified as the source of high sound levels then the next step is to identify where the noise is coming from.

INLET/DISCHARGESilencers can be fitted in the inlet or discharge ducting, and are effective at reducing noise emissions. There is however a penalty to pay in the fan power associated with the pressure drop only suited for clean applications. If there is a significant amount of dust or moisture in the gas stream then dust may accumulate in the plate perforations and absorptive material and result in a rapid deterioration of attenuation. In that case a reactive silencer is the more suitable option.

FAN CASINGInsulating the fan with absorptive material can reduce noise emanating from the fan casing.

SHAFT SEALWhat may at first appear to be noise transmitted through the casing could in fact be escaping through the seal between the fan shaft and casing. Repairing the seal or fitting a more effective one can reduce noise round the fan significantly.

FLEXIBLE JOINTSThe flexible joints between the fan casing and ducting can be an acoustic weak point. Noise can be reduced either by fitting new joints made of a material which has better attenuation properties. The most effective joints incorporate a flow liner, bolster and a flexible fabric as the outer layer.

STANDARD FAN RANGE OR CUSTOM ENGINEERED FAN?Many medium industrial fans available today are selected from standard ranges of pre-engineered designs and sizes. The manufacturing process economies resulting from the limited engineering and design requirements for standard fans are substantial, and allow the cost of manufacture and delivery period to be greatly reduced.

The concept of a pre-engineered standard fan range may lead to technical compromise in the interests of maintaining a ‘standard’ product. Applications that are unusual, or are critical to plant operation, should be subjected to careful examination.

The compromises that have been built into the pre-engineered fan can include high power consumption, mechanical unreliability, excessive noise and sensitivity to out of balance forces that will result in frequent and costly nuisance trips. A custom engineered fan ensures that every element of the unit is precisely designed and optimized to meet detailed specifications for stress, corrosion, erosion, equipment life requirements, safety and material properties.

The design of fan shafts takes into account the stiffness of all elements of the rotor support system, including the client’s foundations. This ensures that the rotor is not sensitive to out of balance forces.

A detailed impeller stress analysis is carried out to ensure that safety considerations are satisfied. This includes fatigue analysis to ensure adequate stop/start cycles for the proposed operating regime. Material selections and weld procedures appropriate for the application. Bearings are selected to suit the exact requirements for each application.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN DESIGN

Page 36: Howden GlobalMining Australia

34

ADJUSTABLE PITCHAXIAL FLOW FANS

A FIXED OR ADJUSTABLE PITCH AXIAL FLOW FAN OFFERS A COST EFFECTIVE LOW-MAINTENANCE SOLUTION IN APPLICATIONS WHERE FREQUENT FLOW CONTROL IS NOT REQUIRED. TYPICAL APPLICATIONS INCLUDE MINE VENTILATION AND FUME EXHAUST FANS.

Howden fixed pitch axial flow fans combine the proven technology of high efficiency Howden blade designs with aerodynamically optimised inlet and discharge geometry to give exceptionally high operating efficiencies.

Blade pitch can be adjusted when the fan is stopped to take account of changing process conditions.

It is vitally important in the purchase of a manually adjustable axial fan that the range of possible operating conditions is considered carefully. We understand that it is especially important to decide on the maximum operating point so that the fan’s motor size is selected to cover all operating conditions up to that point.

Our fans are designed individually to meet each specification and are supplied as a complete package with all necessary accessories including:

• Shaft top connector or portal connecter (for mine ventilation)

• Drive including motor and controls

• Parallel fan system, including adaptor to vent shaft

• Flow measurement system

• Stall warning and/or prevention systems

• Vibration, temperature and pressure measurement

• Silencers and insulation.

Page 37: Howden GlobalMining Australia

35

THE FAN LAWSThe performance of a series of geometrically similar fans (ones which have all major dimensions in the same proportions) is related by a simple series of equations.

• Flow is proportional to diameter cubed and to speed

Q α D3 N

• Pressure is proportional to density, diameter squared and to speed squared

P α ρ D2 N2

• Power is proportional to the combination of these two

W α ρ D5 N3

These laws are used to predict the performance of a full size fan from a set of model test results. They can also be used sometimes as a rough guide to estimate the performance resulting from a modification to a fan on site.

SYSTEM RESISTANCE LAWSWhen air is moved through a ducted system, the energy transferred to air by the fan is progressively lost by:

• Friction of the air against the duct walls

• Turbulence at bends, dampers and changes of duct section

• Friction of the air through heaters, filters or other items of equipment in the system.

The loss of pressure due to all these sources, which is known as the system resistance, is for all practical purposes proportional to the square of the velocity at the point of the loss. Therefore, for a fixed system, it may be said that the pressure (P) required to pass a given volume of air (Q) through the system will vary as the square of the volume flow rate, i.e. P α Q2. This means that, for a fixed system, the greater the airflow, the more pressure is required. Hence, to double the airflow, pressure from the fan has to be increased by a factor of four.

For example, if the initial flow rate is 6m3/second at a pressure of 3kPa and it is required to double this flow rate to 12m3/second:

P1 =

Q1 2

P2 = Q2

P2 = P1

i.e. P2 = 3 = 12kPa ²

This is true only for a fixed system and a constant air density. Should the system be altered (for example by closure of a damper), the above laws do not apply directly.

FAN SHAPE/OUTPUTAerodynamically, any impeller type (shape) can be designed to perform any duty. However, mechanical considerations will dictate that each fan type is most suited for a particular combination of flow and pressure. Centrifugal impellers are most suited to low specific speed duties i.e. lower flow to pressure ratio. A narrow impeller is an inherently strong impeller design, which can run at very high speeds producing the greatest pressure rise. Wider impellers can produce more flow but mechanical stresses limit the speed and thus the pressure rise. Axial fans tend to be suited to higher flow relative to pressure i.e. higher specific speed duties. Mixed flow is historically selected for an intermediate range, but there is a considerable area of overlap.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN LAWS

( (( (Q2 2

Q1

( (12

6

2

Page 38: Howden GlobalMining Australia

36

AUTO VARIABLEPITCH AXIAL FLOW FANS

A VARIABLE PITCH AXIAL FLOW FAN OPERATES AT HIGH EFFICIENCY OVER A WIDE RANGE OF DUTIES PROVIDING A COST EFFECTIVE SOLUTION IN APPLICATIONS WHERE THE FAN OUTPUT MUST BE CHANGED FREQUENTLY TO MEET THE NEEDS OF THE PROCESS.

Howden introduced the first variable pitch axial flow fan for power generation in 1951. Since then the company has manufactured more than 2500 VP axials ranging from 100 to 12000 kW and from 1000mm to 5300mm diameter. Extensive model testing in the Howden internationally accredited laboratory, backed up by years of testing in the field have enabled Howden to develop the most efficient fans on the market. Modern high-pressure blade profiles have significantly reduced the size of the fan needed to satisfy a given duty and can be retrofitted to existing fans to increase output. Blades can be supplied in a variety of materials, to suit the operating conditions, in particular the temperature and the type and quantity of dust in the gas.

A hydraulic control system provides virtually hysteresis free flow control and is fail-safe – the blades will remain in position if loss of hydraulic power occurs. Howden axial fans are designed to minimise maintenance. All impeller components can be serviced or replaced in-situ without removing the rotor from the fan. Each blade is balanced individually and can be replaced on site without rebalancing the complete rotor. A patented counter rotating blade support bearing distributes wear evenly over the full circumference of the race, greatly increasing the life of this key component. The outlet casing can be rolled away from the fan to allow access to the bearing assembly.

Page 39: Howden GlobalMining Australia

37

UPGRADING FANS:REDUCING POWER CONSUMPTIONFor many reasons, a fan may be absorbing more power than it needs to perform the required duty. The fan may be an inefficient design, it may not be matched to the system or it may not have the most appropriate method of flow control.

MORE EFFICIENT IMPELLERAn inefficient impeller can be replaced by a higher efficiency design, producing the same output with a lower power consumption. Some modifications to the fan inlet casing may be required.

MATCHING FAN AND SYSTEMIf a fan is oversized and is running with inlet vanes partially closed, a new impeller, providing the flow that the system needs, will reduce power consumption.

CHANGE FAN SPEEDSimilarly, it may be possible to reduce the fan speed and still provide the flow required when the inlet vanes are opened up.

REDUCE IMPELLER DIAMETER (CENTRIFUGAL FANS)In some cases it will be possible to modify the existing impeller, eg by shortening the blades, to reduce its output. This can be carried out without significantly affecting the basic fan efficiency, therefore the fan can run with vanes fully open, at peak efficiency.

MODIFY THE SYSTEMReducing the pressure drop in the system will reduce the fan power consumption. A thorough survey of the system (the ducting and other components such as dampers and silencers) can in many instances identify improvements which will reduce the overall resistance in the system. Ductwork bends in particular are a prime source of pressure drop, and techniques such as smoothing the curves, installing a set of specially designed vanes or altering the layout can produce useful results.

CHANGE FLOW CONTROLIf the fan duty varies regularly then it may be economically viable to fit a variable speed control to the fan, though in many cases the capital cost will outweigh the power savings.

UPGRADING FANSVARYING OUTPUTIn most applications it is necessary to vary the output of the fan on a regular, or even continuous basis, as the needs of the process change. There are a number of ways to do this.

The simplest way to vary output is to use a damper somewhere in the system. This however is an extremely inefficient means of output control as the pressure drop across the damper wastes power. There is also a risk that the fan could be forced into stall operation.

SPEED VARIATIONSpeed variation is a very effective means of reducing power consumption at lower loads.

VARIABLE SPEED DRIVEA variable speed motor or turbine allows the fan to operate at high efficiency at all duties, however the capital cost is high compared to other alternatives.

HYDRAULIC COUPLINGA variable speed hydraulic coupling allows the fan speed to change while being driven by a constant speed driver. However as the fan speed drops slip losses in the coupling become greater and overall efficiency is lower than when using a variable speed driver.

BLADE PITCH VARIATION (AXIAL FANS)Varying the blade pitch of an axial flow fan is also a very effective way of varying fan output. At lower loads it is not quite as efficient as variable speed but it is significantly cheaper on large fans.

INLET VANE CONTROL (CENTRIFUGAL AND MIXED FLOW FANS)This is a relatively low cost method of varying output, but the power consumed is higher that the variable speed alternative. This method can vary flow over a wide range but cannot reduce it to zero due to leakage through the vanes. At high turndown the inlet vane controls on larger fans will excite high levels of vibration in the impeller structure that may result in fatigue damage to the impeller. It is not suitable for applications with high quantities of erosive dust as the high velocities over the vanes result in a high rate of wear.

INLET LOUVRE DAMPERS (CENTRIFUGAL FANS)These work in a similar way to inlet vane control, but are situated in the inlet box rather than the fan inlet. Inlet louvre dampers are less effective than inlet radial vane controls but are better suited to applications that involve high levels of erosive dust as gas velocities are much lower than radial vane controls.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN POWER & SPEED

Page 40: Howden GlobalMining Australia

38

HEAVY DUTYMIXED FLOW FANS

THE MIXED FLOW (OR AXIAL IMPULSE) FAN IS A COST-EFFECTIVE ALTERNATIVE TO AN AXIAL FLOW FAN IN SITUATIONS WHERE CAPITAL COST AND RESISTANCE TO EROSION ARE AS IMPORTANT AS POWER CONSUMPTION.

The impeller consists of curved steel plate blades, which are welded to a conical hub. This simple robust impeller is ideal for handling dust-laden gases at elevated temperatures. Impulse bladed mixed flow fans are controlled by inlet radial vane controls similar to those used with centrifugal fans. This form of control is extremely effective, and allows rapid changes in fan output in response to process demands. The inherently low velocities within the impeller result in low wear rates in dusty environments. As the aerodynamic performance of the fan is not sensitive to wear on the blade profile, the fan output is not noticeably degraded by erosion or corrosion, and the fan will maintain high operational efficiencies over a long period of time without the need to replace the blades.

If required, the fan can be supplied with a passive stabilizing chamber which modifies the fan

performance characteristic, and eliminates the stall characteristic. The aerodynamic design of the stabilising chamber can be adjusted to allow the available pressure at low flow to be controlled to suit specific process requirements. Howden has supplied a large number of mixed flow fans; up to 5000mm diameter, with motor powers ranging from 350kW to over 9000kW.

The main applications for mixed flow fans are:

• Boiler draught: In situations where dust in the flue gas precludes the use of an axial fan and where the flows are too high for a double inlet centrifugal fan.

• Mine ventilation, where its compact, robust design can be the most technically effective for primary ventilation and underground booster applications.

Page 41: Howden GlobalMining Australia

39

Pressure(kPa)

Flowm3/sec

100

100 100010

10

5

1

Centrifugal

AxialMixed Flow

AXIAL, CENTRIFUGAL OR MIXED FLOW FANThe choice of fan type for any particular duty has necessarily to address issues beyond those of impeller type as the operating range of centrifugal fans by example, largely envelops axial and mixed flow.

CENTRIFUGALCentrifugal fans can handle a wide range of volume and pressures. As volume increases pressure decreases due to mechanical design limitations of the impeller (larger diameter, wide fans, have lower maximum tip speeds). Fan geometry is flexible allowing for double inlet with wide impellers and aerofoil blades to maximise efficiency. Where larger pressure rises are needed narrow impellers with longer blades are available. Generally a fan should be selected at as fast a speed as possible to reduce size and capital cost, however centrifugal fans running at a slower speed may give a better efficiency. Where erosion of the fan blades due to dust burden is a problem the slower running centrifugal fan is best.

AXIALAxial fans are able to handle large gas volumes at lower pressures. Maximum rotational speeds higher than centrifugal fans and only limited by centrifugal load on the blade support bearings. Generally larger volumes have the largest hubs and each hub size can be fitted with various lengths of blades. The hub speed sets the pressure rise and the blade length determines the volume flow. Two stage axial fans develop higher pressures but at an increased capital cost. Aerofoil blades and auto-variable pitch control enable performance over a wide range of duties at high efficiency. Best suited to clean gas environments, but will operate in moderate dust environments if fitted with steel blades. Not suited to ‘dirty’ gases.

MIXED FLOWAs the name suggests combines the features of an axial and a centrifugal fan, although the impeller looks more like fixed bladed axial type. Efficiency can match other types of fan, within its optimum operating envelope. Impeller design is robust and the plate blades are ideal for handling dust laden gases at elevated temperatures. Fan performance is less degraded by erosion or corrosion, and the blades are easily weld repaired.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN CHOICES

Page 42: Howden GlobalMining Australia

40

AUXILIARY AND PORTABLE FANS

AS PART OF OUR COMPREHENSIVE FAN OFFERING TO THE MINING INDUSTRY, HOWDEN HAS A RANGE OF LOW AND MEDIUM PRESSURE/VOLUME MINE AUXILIARY AND IN-LINE JET FANS FOR TAKING FRESH AIR WHERE IT IS NEEDED MOST ON A MINE, THE WORKFACE.

Our auxiliary fans are designed to convey air at flow rates of up to 26m3 per second, and are available in two, and four-pole design configurations.

Four-pole fan technology has been employed to develop a hard-wearing, robust fan that overcomes the drawbacks of traditional auxiliary mine fans. Howden auxiliary fans therefore offer increased bearing life and lubrication intervals and better maintenance performance, lowering fan operating costs and reduced fan inventories result. As standard supply, noise levels are reduced to within 16dB(A) SPL, without the need for silencing equipment. Depending on the customer requirement, our auxiliary and jet fans can be mounted on skids for excellent portability.

Applications:

• Return air ducting

• Brattice wall boosting

• Cooling car forced draught.

ORKFACE.

Brattice wall boosting

Cooling car forced draught.

Page 43: Howden GlobalMining Australia

41

STALL PREVENTION AND MITIGATIONAll high efficiency fans exhibit an aerodynamic stall. As the fan is throttled back i.e. as the system resistance increases a point will be reached where flow separates from the blades and stall occurs.

When a fan is in stall, the blades are shaken. Axial fan blades are only supported at one end, so are inherently flexible, resulting in excessive blade vibration and eventual blade failure at the blade root.

For centrifugal fans the blades are much stiffer and stronger, due to being supported at both ends, so stall is not as severe a problem. The main exception is paddle bladed fans, which, like mixed flow and axial fans, have the blade only supported at one end, so will more readily fail in stall. Regardless of the integrity of the impeller, stall will induce high duct vibration increased noise. It has been known to lead to duct and silencer failure due to weld fatigue.

Stall prevention starts at the fan selection stage:Avoid selecting too large a fan for the application as may result in operation in the undesirable part of the fan curve where stall and surge can occur. Better select a higher class of fan that can be run at a higher speed should the system resistance calculation be in error. On variable pitch axial flow fans, reducing the blade angle and increasing the speed can help avoid stall. An anti-stall impeller casing can be fitted to axial fans on the suction side of the impeller in order to absorb and turn the turbulent airflows produced at the tips of the blades when the fan is operating in the stall area. Alternatively, stall monitoring devices can be fitted close to the blade inlet to register the pressure difference in the airflow. These can be used to send an alarm signal to a control room before the fan stalls or activate a control device which, in connection with variable blades, will automatically get the fan out of the stalling condition.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN STALL

Page 44: Howden GlobalMining Australia

42

COOLING FANS

HOWDEN’S COOLING TOWER AND DRY COOLING FANS ARE SUITABLE FOR USE ON LARGE BOILER HOUSES AT MINES AND ON PROCESS PLANTS.

Whether they are used for wet or dry applications, our well-specified and engineered fans produce a combination of performance and efficiency for the lifetime of project for which they are designed.

Howden cooling fans provide the highest flow of air, and also maximise energy efficiency.

Modern fan selection software is employed to help determine the correct shape and rotational speed of the fan blades necessary to produce more pressure, and therefore a better flow of air, be it for dry or wet cooling.

All fan systems are matched to individual applications. Where Howden cooling fans are prescribed for use in wet or hostile environments in which blades are exposed to aggressive attack by fluorine compounds, a low-porosity material is applied to blade surfaces to improve their durability. These fans have significant advantages over alternative materials used for fan blades, for instance aluminium, which corrodes and pits in environments with exposure to acid water.

Each of our fan types has its own unique characteristics in terms of efficiency, noise levels and areas of use.

E-SERIESThis is a classic straight aerofoil fan with a highly-efficient impeller and/or low noise. This is the most widely-used fan in the range and it is available in three different blade profiles:

• ENF – low noise

• ELF – extra low noise

• ELFA – designed for clockwise rotation in the horizontal or vertical planes.

K SERIESK Series axial fans are designed for use in factory-assembled cooling towers and air-cooled heat exchangers, with superior performance at lowest power consumption and with time-saving features. Fan blades with the innovative Howden-patented

“Aerotip” and the radius-cut inboard edge; have been designed for a high power recovery, providing excellent aerodynamic performance.

SX SERIESHowden SX axial cooling fans are among the best low-noise fans available for use in evaporative cooling systems and ventilation systems where strict fan noise levels apply. Their specially-shaped aerofoil shape is designed for ultra-low noise applications for clockwise rotation in the horizontal or vertical positions.

Z SERIESZ Series axial cooling fans are the latest in axial fan development, being specifically designed to operate at peak efficiency at the most common duty points in field erected cooling towers and air-cooled steam condensers. They include Howden’s innovative, patented “Aerotip” blades which enhance the aerodynamic performance and significantly reduce the “pressure pulse” transmitted to the fan ring.

Page 45: Howden GlobalMining Australia

43

NOISE LEVELS AND MEASUREMENTAt noise levels in excess of 75dB, noise significantly impedes communication, causes stress and can cause permanent measurable hearing damage. However, the acceptable noise level is a compromise between the effect of the noise and the cost of reducing it. Currently in industrial environments 85dBA is seen as the maximum acceptable noise level.

Noise is seen to act over time, so 85dBA is the maximum for an eight-hour day. For shorter times, higher noise levels are acceptable, each halving of the time increasing the acceptable level by 3dB. For a two-hour period an acceptable level would be 91dBA. This can be referred to as 85dBAeq.

The location for measuring industrial noise is 1m from a machine surface. This should be where people are expected to work.

For environmental noise the acceptable levels are much lower. Higher noise is acceptable during the day because the overall background noise is higher and people, being more active, pay less attention to noise. In addition to dBAeq, which is the average over the sampling time, the time variation of environmental noise is important. This is expressed in terms of the percentage of the time the noise is above a certain level. For example dBA10 is the level the noise is above for 10% of the time.

The location for measuring environmental noise is the plant boundary.

ENVIRONMENTAL EFFECTFor machinery the predicted sound pressure levels are with the machine placed in an open environment. This is referred to as free field. It is required because the machine supplier does not know the environment in which the machine would be placed.

The effect of the environment is very important on the sound pressure level. It can affect the sound pressure level by over 10dB. This means that for a fan with a predicted casing breakout sound pressure level of 85dBA the on-site level may be in excess of 95dBA. This is because of:

LOCAL EFFECTSAgainst a wall, the noise has 50% of the original area to escape through giving a 3dB increase in sound pressure. Against a corner, the noise has only 25% of the original area to escape through, giving a 6dB increase in sound pressure.

GLOBAL EFFECTSThis depends on the size of the machine relative to the room it is in and on the sound absorption in the room. A large machine in a small room with hard walls would have a much higher sound pressure level at 1m than the same machine in free field conditions.

Some end users get round this problem by assuming an environmental factor of 5dB, requesting that equipment meets 80dBA free field. In addition to the manner sound propagates in the environment, there are other noise sources. A typical installation has two of the same machines located side by side. This gives a 3dB increase in the sound pressure. Of greater importance to fans is duct breakout noise. Due to the large area of duct in typical applications, this can be the dominant noise source and can give high noise at areas remote from the fan.

MEASURING NOISEThere are two types of instruments for measuring machinery noise. Standard microphones measure sound pressure and are good where the machine’s direct noise is dominant (i.e. no more than 3dB below the total noise). Sound intensity microphones measure the amplitude and direction of sound pressure and are good where the machine’s direct noise is at least significant (i.e. no more than 10dB below the total noise).

The bigger the machine and the more accurate the result required, the longer the test will take.Environmental noise is normally measured at one location with the sound meter left running for between one hour and eight hours to get a statistical measure of the noise.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN NOISE LEVELS

Page 46: Howden GlobalMining Australia

44

ELECTRICAL, INSTRUMENTATION AND CONTROL SYSTEMS

HOWDEN OFFERS TURNKEY ELECTRICAL CONTROL AND AUTOMATION PRODUCTS THAT ARE ENGINEERED FOR THE CUSTOMER’S PROCESS SPECIFICATIONS. WE MANAGE THE COMPLETE AUTOMATION OF LARGE PROJECTS, FROM THE TENDER STAGE, THROUGH TO FINAL COMMISSIONING.

Besides automatic electrical control and instrumentation systems for new plants, these systems can also be retrofitted to existing plants, or existing systems can be upgraded.

Howden has extensive experience covering combustion systems, fans, fabric filter plants, dust control, scrubber plants, waste gas extraction systems, automated wire patenting lines, (including lead treatment and galvanising baths) automated aluminium solution treatment and age hardening furnaces, combustion systems for sinter plants, carbon baking furnaces and incinerators.

All electrical and instrumentation projects are executed with a personal touch, regardless of size and value.

MOTOR CONTROL EQUIPMENT Supply, install and engineer Motor Control Equipment (MCCs) for all types and equipment. Capabilities include MV and LV turnkey systems. Containerised systems for remote locations are engineered and supplied as per customer needs.

FIELD CABLINGSupply, install and engineer electrical and instrumentation cabling to local electrical standards, and certificates of compliance testing are submitted by Howden for all installations.

PROGRAMMABLE LOGIC CONTROLLER SYSTEMSHowden’s in-house programmers design Programmable Logic Controller (PLC) software

for the major types and brands of PLC and SCADA systems. PLC panels, complete with PLC systems, are supplied and designed.

FIELD INSTRUMENTATIONFit-for-purpose instrumentation is designed, supplied and installed on all projects as per customer requirement.

Page 47: Howden GlobalMining Australia

45

MATCHING THE FAN TO THE SYSTEMFan performance, which is defined as the possible combinations of flow and pressure that a given fan can produce can be graphed, conventionally with flow on the horizontal and pressure on the vertical axis. The characteristic of the system, which in most cases takes the form of a parabola where pressure is proportional to the square of the flow, can also be drawn on this graph. The point where these two curves intersect is the only one at which the fan can operate with this system. To vary to flow of gas in the system, either the fan characteristic or the system characteristic must be altered.

The fan characteristic can be changed by techniques such as:

• Varying the speed,

• Using an inlet control device such as inlet vane control or by

• Varying the blade angle (axial flow fans).

System changes are most commonly carried out by adjusting dampers or by changing a feature of a system. If the system resistance changes over time, or has been incorrectly calculated then the performance of the fan will change. A higher resistance will result in lower flow, and if high enough could put the fan into stall. A lower resistance will result in greater flow and increased shaft power.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN SYSTEMS

Fan

Stat

ic P

ress

ure

kPa

Volume Flow m3/s

0

0

1

2

3

4

5

6

20 40 60 80 100 120 140 160 180

Fan Operating Point

Fan OutputCharacteristicat 100% Speed

Page 48: Howden GlobalMining Australia

46

COMPRESSORS

HOWDEN HAS A DIVERSE RANGE OF TOP-QUALITY COMPRESSOR PRODUCTS AND SYSTEMS WHICH HAVE BEEN DEVELOPED TO CATER TO DIFFERENT INDUSTRY AND PERFORMANCE REQUIREMENTS.

We are therefore well-placed to support several mine-focused practices, including Underground Coal Gasification (UCG) processes. Here our multi-stage high flow axial compressors are engineered and manufactured to deliver combustion air to injection wells prior to the gasification process.

Howden has also developed a methane gas abatement solution for coal mines, and some gold mines, where we supply gas compressors to return collected high concentration methane gas to the surface at pressures suitable for fuelling internal combustion engines, or for heating and cooling applications.

TURBO COMPRESSORSThe Howden Donkin range of integrally geared, high efficiency single stage turbo compressors has been developed for use in a broad range of process applications.

The integration of overhung high efficiency impeller, precision gears and high stability bearings result in

smooth, minimum power loss transmission. Pressurised oil lubrication with high integrity protection systems ensures maximum availability of equipment.

LOW PRESSURE GAS BOOSTERSThe robust V Series of pressure gas boosters is designed for fuel gases such as landfill gas, coke oven gas, natural gas and propane/air mixtures.These reliable units have a virtually infinite life span.

PISTON GAS COMPRESSORSHowden offers a full range of piston compressors custom designed to process applications. The Burton Corblin range provides pressures up to 350bar, flows to 22,000 sm3/hr and powers to 2.5 MW. These small to medium size compressors have a number of additional features including complete separation of the product from the crankcase, purged packing and double distance pieces for leakage prevention, and lined cylinders for longevity and corrosion resistance.

Thomassen supply large piston compressors with drives up to 25MW for special applications. These compressors can be provided with additional patented features such as the Free Floating piston technology which considerably increases the life of piston rider and compression rings.

ROTARY COMPRESSORSThe Periflow® gas compressor is a rotary regenerative compressor that offers the same performance as low-flow-rate centrifugal compressors, but at a much lower speed and with surge-free operation. It is ideal for applications calling for high pressure and relatively low flow rates.

DIAPHRAGM GAS COMPRESSORSBurton Corblin diaphragm compressors maintain gas purity during compression with no leakage. All gases can be handled, including light or heavy, high purity, rare, toxic, flammable, corrosive, explosive, and radioactive.

Page 49: Howden GlobalMining Australia

47

TWIN SCREW COMPRESSORS PRINCIPLES OF OPERATION Compression is achieved by the intermeshing of two helical rotors contained in a suitable casing. Figures 1–4 give details of the compression cycle. The Howden twin screw compressor is a positive displacement rotary design. As such it has the characteristics and stability of reciprocating compressors but in addition offers particular advantages:

• Reduced physical size

• Fewer moving parts

• Low vibration

• Extended operating life cycle.

OPTIONSOur compressors have a range of design options.

Typical ones are:

• Twin wall construction with sleeve bearings

• Single wall construction with roller bearings

• Slide valve capacity control from 100% to 10% nominal

• Inverter speed control

• Variable volume ratio

• Superfeed

• Oil cooling

• Liquid refrigeration injection

• Specialist sealing systems.

FEATURES AND BENEFITSPositive displacement

• Cannot surge. High compression ratios per stage.

Rotary action

• Vibration free running.

• Extreme reliability & on-line availability.

• Smooth gas flow, low pulsation.

• Lightweight foundations.

Stiff action rotors

• Ability to withstand high pressure differences.

No inlet or outlet valves

• Lower maintenance costs.

Compact size & light weight

• Minimal space and foundation requirement, resulting in low installation costs.

Designed for long periods of continuous running

• Maximum on-line availability.

• Minimal service requirements.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

COMPRESSORS

Page 50: Howden GlobalMining Australia

48

ATTENUATORS

THE HOWDEN FAMILY OF ATTENUATORS OR REACTIVE SILENCERS HAS BEEN DEVELOPED SPECIFICALLY FOR APPLICATIONS WHERE DUST OR MOISTURE AFFECT THE ATTENUATION PROPERTIES OF CONVENTIONAL ABSORPTIVE SILENCERS.

This can lead to the accumulation of dust in the plate perforations and absorptive material, resulting in a rapid deterioration of attenuation performance.

REACTIVE ATTENUATORSOur pure reactive attenuators, based on the Helmholtz resonator principle, are ideally suited for operation in contaminated air and gases, especially where moisture carry-over is a problem.

Within a specifically tuned acoustic chamber, sound waves corresponding to the tuned frequency are reflected out-of-phase with the incoming sound waves, and therefore have a cancelling effect on each other, reducing noise levels.

With its reactive-dissipative attenuators Howden has extended this concept to produce a silencer that attenuates over a wider range of frequencies that have previously restricted the use of these types of silencers.

A series of resonator cavities, tuned to the specific application, attenuates noise over a range of frequencies. Special materials are available for corrosive or high-temperature applications.

Compared to an absorptive silencer, life is extended and maintenance is minimised due to the lack of light gauge perforated plates and absorptive material.

REACTIVE-DISSIPATIVE ATTENUATORSHowden reactive dissipative attenuators extend the concept further by incorporating absorptive fill material within the acoustic chambers to widen the attenuation range of each cell. The fibreglass fill is situated out of the air stream, shielding it from contamination by particulate matter. Contamination of the fibreglass with dust or moisture can be tolerated with only a minimal change in acoustic performance.

PURE REACTIVE ATTENUATORSFeatures

• Long service life

• Non-fouling design

• Minimum maintenance

• Easy cleaning

• Low pressure drop

• Flexibility of design

• Suitable for high temperatures

• Broad attenuation range

• Available in various materials

Applications

• Mine ventilation

• Induced draught fan systems

• Contaminated gas streams

• Saturated gas streams

• Corrosive gas streams

• High temperatures

• Steam vent systems

Page 51: Howden GlobalMining Australia

49

BASIC ACOUSTICSSound power level is the acoustic energy emitted by a source such as a fan and is typically measured in Watts (W). Sound pressure level is the pressure the acoustic wave generates at a particular point and is typically measured in Pascals (Pa or N/m2). Sound pressure level is a function of the sound power level, distance from the source and of the attenuation between source and measuring point

The human ear is an extremely sensitive instrument and can detect sound pressure levels ranging from 0.0002Pa to 60Pa. The decibel scale has been devised to make the numbers more manageable. Firstly a reference level, W0, is chosen for sound power (10-12W). Any other sound power level is ratioed to the reference value, and to reduce the range of numbers the logarithm to the base 10 is calculated. As this unit, the Bel, is rather large, it is subdivided into tenths, ie decibels, (dB):

Lw = 10 log (W/W0) dB

The sound power generated by a fan (Lw) is proportional to diameter, speed and density as indicated by the following formula:

Lw α 70 log D + 50 log N + 20 log ρ

If a sound source doubles in power the decibel level will increase by 3dB. Similarly, the reference level P0 for sound pressure is 2x10-5Pa and in this case the formula is:

Lp = 20 log (P/P0) dB

If a noise measurement doubles in pressure the decibel level will increase by 6dB.

OCTAVE BANDSA fan generates noise over a wide range of frequencies. It is important to know how the power or pressure level is spread over the range to predict accurately the sound propagation. By convention the frequencies are divided into a specified range of octave bands and the power or pressure in each of the bands is measured or calculated separately. A total sound or pressure level can then be obtained by logarithmically adding together the values in each of the octave bands. Two fans generating the same total power will sound entirely different to a listener if the energy is spread differently over the octave bands. The ‘A weighted’ scale has been devised to simulate the sensitivity of the human ear. Corrections to each octave band are applied and then the resultant levels are totaled logarithmically to give and ‘A weighted’ total in dBA.

ENVIRONMENTAL NOISE REDUCTIONThe propagation of noise from mine ventilation fans and exhaust stacks to nearby residential dwellings will be affected by local meteorological conditions. The intrusive noise level at the noise sensitive receiver will fluctuate due to wind direction and atmospheric temperature gradients. These effects account for significant noise level fluctuations at the receiver. Excursions in predicted noise levels can be in the order of +10dB (over neutral meteorological conditions). Additionally, the acoustic character of tonal noise sources such as vent fans and stacks creates greater annoyance at residences. These tones are related to the Fan Blade Pass frequency and are a focus for efficient silencer design.

Performance testing on absorptive silencers fitted on coal-fired boilers has shown a reduction in attenuation of around 60% after 15,000 hours of operation. Even following costly cleaning, these silencers seldom return to their original performance. A reactive dissipative stack silencer can provide an effective long term performance solution in the contaminated gas stream and can be tuned to focus attenuation on the blade passing tones.

The main section of a reactive dissipative stack silencer are the splitters which comprise a number of chambers, the depth of which are approximately one quarter of the wavelength of the frequency the chamber is designed to attenuate. Sound waves entering these chambers are reflected with a phase change of 180˚ which partially cancel the entering waves.

Absorptive material is fitted to the downstream faces of the elements to broaden the attenuation characteristics. A pure reactive section at the rear of the splitters, designed on the Helmholtz resonator principle, consists of a number of tuned cavities to enhance attenuation at frequencies below 125Hz. With this type of device blade passing tones can be reduced by 30dB.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

ACOUSTICS

Page 52: Howden GlobalMining Australia

50

CENTRIFUGAL BLOWERS

HOWDEN SINGLE AND MULTI-STAGE CENTRIFUGAL BLOWERS SUPPLY LOW VOLUMES OF AIR AT HIGH PRESSURE, PROVIDING A COST EFFECTIVE, HIGHLY RELIABLE AND EFFICIENT, LOW NOISE ALTERNATIVE TO A COMPRESSOR.

TYPE RRO CENTRIFUGAL BLOWERSType RRO single and two stage blowers are machined from solid forgings, and the casings are manufactured from heavy castings to give a strong rigid construction. They are supplied in a wide range of corrosion, abrasion and temperature resistant materials to satisfy specific process conditions, and can also be supplied to API Standards if required.

High efficiency open type radial bladed or backward curved blade impeller designs are available.

Blowers are fitted with inlet inducer vanes, inlet radial vane controls and optional variable vane diffuser controls to operate at very high efficiency over an extremely wider flow range.

The rotor and integral gearbox are engineered together to ensure that all bearing, stress and rotor dynamic considerations are satisfied.

Depending on application requirements, anti-friction bearings or advanced technology tilting pad thrust bearings and tilting pad journal bearings are supplied for the high-speed rotor. The complete unit is composed of blower, gearbox, control panel, drive motor and integral lubrication unit are skid mounted for ease of transport and installation.

TYPE RRC CENTRIFUGAL BLOWERSType RRC multi stage centrifugal blowers are used in the mineral processing and chemical industries. Typical applications include flotation cells, waste water treatment, fluidising blowers and combustion air blowers. Directly coupled to two pole induction motors, they provide a cheaper, more efficient and quieter alternative to positive displacement blowers.

The blowers incorporate fully-fabricated impellers and casings. This allows for an extremely wide range of readily welded materials to be considered for construction.

The impeller inlets and stationary inlet cones are machined to ensure optimum aerodynamic performance, and each impeller stage is provided with a set of inlet control vanes that provide high efficiencies over a wide operating range.

The complete blower assembly and drive motor are carried on a single integral base unit which simplifies transport and installation.

Maintenance is simplified. These units do not require any special skills other than those normally associated with fan maintenance and service.

Page 53: Howden GlobalMining Australia

51

ASSESSMENT OF PLANTThe assessment of compliance of process screw chillers, ice plants and turbo blowers with specification can be difficult. Asking some relevant questions, or considering certain design aspects within an offer, will assist with the assessment process.

Checklist for Process Screw Chiller Technologies

• Is the evaporator and condenser material compatible with the quality of water to be used, and has adequate allowance been made for fouling factors likely in the relevant application?

• Are the pressure vessels manufactured in accordance with recognised codes?

• Does the chiller comply with local refrigeration plant standards?

• Does the compressor have sleeve bearings and a double-wall casing for long service life and low noise levels?

• Does the oil tank have both demisters and coalescing cartridges for optimum oil separation?

• Does the package include dual lube oil systems that permit standby capacity for emergencies or allow for on-line servicing?

Checklist for Ice Plant Technologies

• Ice mass fraction to be specified, which is dependent on the Total Dissolved Solids (TDS) in the feed water, and the concentration in the sump.

• Sump blowdown rate will determine the build-up of TDS and chlorides in the sump.

• Materials of construction for the ice plates will depend on the corrosiveness of the feed water – especially the chloride concentrations.

• Cycle time will depend on the defrost system employed and the mass of material in the ice-making plates.

• Refrigeration compressors’ absorbed power can be reduced by employing refrigerant sub-coolers and/or economisers.

• The ice plant performance coefficient should include the total system, since looking at system components only will reflect misleading efficiencies.

• Is the ice plant contained within an insulated building to reduce heat gain?

• Is the refrigerant used in the system environmentally friendly?

HOWDEN DONKIN TURBO BLOWERS

• What is the duty turndown capacity of the blower to achieve optimum efficiency over the entire operating range?

• Does the gearbox incorporate a split casing design to allow easy access to gears and bearings?

• What fail-safe features are incorporated into the blower lube oil system design?

• Is the blower equipped with a dual oil filter system for on-line servicing?

• Does the blower design guarantee oil free process gas delivery, if required by the application?

• Does the blower come with a fully-automatic PLC based control incorporating anti-surge features and simultaneous “multi-blower installation” control?

HOWDEN PRODUCTS

HOWDEN KNOW HOW

COMPRESSOR ASSESSMENT

Page 54: Howden GlobalMining Australia

52

HARD ICE PLANTS & THERMAL ICE STORAGE

THE DEVELOPMENT OF DEEP-LEVEL MINES TO BEYOND 2000M BELOW THE SHAFT COLLAR, AND A GROWING PRE-OCCUPATION WITH THE COST OF MINE ENERGY, HAS GIVEN IMPETUS TO THE DEVELOPMENT OF HOWDEN’S TURNKEY HARD ICE AND THERMAL ICE STORAGE TECHNOLOGIES.

HARD ICE Howden’s efforts to provide cooling to deep mines where the efficiency of traditional chillers and bulk air coolers is compromised has seen us emerge as the global market leader in the design, build and installation of hard ice plants.

The scope of work typically includes all civil work, ammonia compressor plant, ice makers, cooling towers, ice conveyors and the electrical and control system to deliver hard ice to the mine shaft.

Our plate ice technology can be used with normal mine service water to produce ice with an Ice Mass Fraction (IMF) of up to 98%. Howden oil injected screw compressors are used with environmentally-friendly ammonia refrigerant to provide the ice freezing capacity, and a de-superheated hot gas defrost cycle is used to release the hard ice.

The ice is transported underground in HDPE pipes and is utilised in underground melting dams, with the very cold water being distributed to the various cooling stations with resulting enhanced thermal

performance of underground Bulk Air Coolers (BACs) and spot coolers.

The overall cooling system energy efficiency of a hard ice plant exceeds that of a chilled service water cooling system; primarily due to the saving in return water pumping energy (hard ice has a cooling capacity four times greater than water, resulting in a large reduction in return water to be pumped back to the surface). The reduction in required pumping capacity also reduces distribution infrastructure and shaft space requirements.

THERMAL ICE STORAGEHowden can supply ice-making technology with which either “ice water” or “solid ice” is produced as required during any specific 24-hour period, making major power and demand savings possible when it is used in combination with good water management systems.

The water management philosophy, including ice melting, storage, and ice and ice water blending, can be structured to allow the entire mine

refrigeration plant (excluding the pumping of the chilled water) to be stopped during a power peak demand period per week.

Our plant will run at maximum load at all times thus delivering complete efficiency. As the system is designed as a standalone operation, it will not reduce dam storage volumes, and can operate even if the main cooling plant is out of operation. Minimal additional pumping costs are required.

Safety is an integral part to the design. All the icemakers are above water level and can be individually isolated, thus ensuring the system is safe. Icemakers are also grouped in modules which can be isolated if necessary, for both safety and service reasons.

Our plant typically consists of an ammonia screw compressor and modular ice water maker, but could also include submerged coils for hard ice production. A typical modular size plant is designed to deliver about 5MWR per unit.

Page 55: Howden GlobalMining Australia

53

FAN BID ASSESSMENTBids received from a number of suppliers can seem, at first sight, to be indistinguishable. Asking a number of simple questions can help to ensure that the fan bids all comply with the specification.

LAYOUT

• Does the fan inlet and discharge cross-section match the ductwork, or must a transition piece be supplied?

• If there is a bend in the ductwork close to the fan discharge it may significantly affect the fan performance. Has that been factored in?

DUTY AND PERFORMANCE

• The upstream ducting layout may affect the fan performance. Has this been assessed?

• Has the same definition of fan pressure been used? ‘Fan total pressure’, ‘fan static pressure’ and ‘static pressure rise’ are all different quantities.

• What is the margin between motor name-plate rating and fan absorbed power? If it is too small there may be insufficient safety margin. If it is too large it may indicate that the supplier is unsure of the fan’s performance.

There are a number of different ways in which fan efficiency can be specified, so it is better to assess fans on the basis of shaft power.

• Is there enough reserve between the operating point and the fan peak pressure point to allow some increases in fan system resistance?

• Is the fan operating in parallel with another one or more? If so can the fans start up with all the others running?

• Is the performance based on an international standard?

FAN SELECTION

• Is the blade shape suitable for the application?

• Does the erosion protection, if used, match the dust type and quantity in the air or gas stream.

• Inlet control – Are the vanes in the eye of the fan, where they control flow more efficiently, or in the inlet box where they will wear less if there is a significant amount of dust in the air or gas stream.

• Has the manufacturer supplied a fan of this size and speed before?

• Fans which operate at very high temperatures may require special materials with acceptable creep rupture properties.

• Has the predicted number of stop/starts been factored into the mechanical design?

• Fan speed. In dusty conditions too high a speed may reduce fan life considerably.

• What is the margin between running and first critical speed of the impeller

• Has the support and foundation stiffness been factored into the critical speed calculation?

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN BIDS

Page 56: Howden GlobalMining Australia

54

DUST COLLECTION AND FLUE GAS CLEANING

HOWDEN BOASTS A SELECTION OF DRY DUST COLLECTION AND SCRUBBER TECHNOLOGIES WHICH CAN BE EMPLOYED AS SPECIFIED BY THE CUSTOMER.

Most of our gas cleaning systems are supplied on a turnkey basis, and include design and detail engineering, supply and manufacture, electrical control and instrumentation, plant erection, commissioning and handover to the customer.

Howden’s engineers also provide technical advice and support on the technologies and systems needed for individual applications. Whichever solution is selected, our gas cleaning systems are designed to meet the most stringent requirements:

• Compliance with relevant environmental legislation

• Cost effective, efficient solutions

• Minimal space requirements

• Low maintenance

• Energy efficient

• Minimal water requirements.

DRY DUST COLLECTORSHowden can supply mechanical dust collectors or fabric filter solutions, depending on the application requirement.

MECHANICAL DUST COLLECTORSMechanical cyclone collectors represent the most simple and economical method of dry dust collection, and we can offer the mechanical collector best suited to the customer’s operation.

Howden mechanical cyclones and multi-cyclones are designed to deliver high and medium efficiencies,

depending on the application for which they are employed.

In step with modern outlet emission requirements, our mechanical collectors are used primarily as pre-collectors before secondary collectors, for instance electrostatic precipitators, or before fans in forced draught systems.

FABRIC FILTER PLANTOur fabric filter plant is suitable for application requirements where emissions below 10mg/m3 are required. Two bag filter technologies are offered, either high pressure reverse pulse jet, or low pressure reverse flow.

Reverse pulse filter technology is particularly appropriate to applications where space for the plant is limited, for instance installations between the boiler and outlet stack of an existing plant. Cleaning of our reverse flow designs is by means of a high-volume pulse through a rotating manifold, which enables a better release of the dust cake, for lower cleaning frequency and longer bag life.

The reverse pulse jet filter offers high performance and a low operating cost, making it a popular choice in many demanding industrial applications.

SCRUBBERSHowden’s wet, dry, and semi-dry scrubbing solutions are proven options for gaseous emission and particulate control, and are suitable for use on high-temperature applications.

A choice of wet scrubbers is available – the highly-efficient Venturi design, and the lower energy Cyclonic scrubber.

VENTURI SCRUBBERSVenturi scrubbers have a particulate collection efficiency of up to 99%. They are suitable for high-temperature processes and applications with a pressure drop of up to 30kPa.

Howden’s Venturi scrubbers are especially good for simultaneous gaseous and particulate pollutant removal when scaling is a problem, and where there is a high concentration of dust in the inlet stream.

CYCLONIC SCRUBBERSThese scrubbers have a lower power requirement for removing particulates and gases from the flue gas stream. They are suitable for pressure drops of up to 2.5kPa.

DRY SCRUBBINGDry injection in conjunction with fabric filtration is an economical, reliable choice for removing low levels of SO

2 and tars in suspension.

GAS COOLINGHowden also offers a range of gas cooling solutions, including dilution air, high temperature quench, radiant and forced draught cooling. These are supplied as turnkey solutions to customer specification.

Page 57: Howden GlobalMining Australia

55

BASIC FAN DESIGN AND EFFICIENCYFan design is both an art and a science. Our skilled and experienced engineers are dedicated to carefully analysing and solving each industry’s specialised needs. When designing efficient impellers, most manufacturers start out by testing a series of impellers with the aim of producing a set of aerodynamic shapes that:

• Cover the required pressure/volume envelope

• Develop a good efficiency across as wide a zone as possible

• Are not sensitive to small geometrical changes

• Preferably have a non-overloading power curve (where the impeller design permits)

• Are relatively easy to manufacture with a minimum cost (probably the most important to the manufacturer).

Although it is relatively easy to design an impeller to satisfy a particular pressure/volume duty, it is difficult to achieve this with a high efficiency while making it cost-effective to manufacture. This means that one manufacturer’s fan may satisfy the duty requirements with a much higher efficiency than another manufacturer’s. The way to save energy when using fans appears simple – use more efficient fans. However, it is not that straightforward. Modern higher efficiency motors have a relatively flat efficiency curve with load, and improving the motor efficiency means improving the efficiency over the whole operating field. The same does not apply to fans – the efficiency curve is far from constant and there can be a difference of 30% between peak and low efficiency in the fan’s working range. In addition, the energy use of similar fans performing the same duty, but from different manufacturers, can vary by up to 30%. It is therefore important to select a fan that is operating as near to its peak efficiency as possible.

Fan specifications should stipulate the use of both a high efficiency fan and a higher efficiency motor to achieve maximum energy savings during the operational life of the equipment. When selecting a fan and specifying a fan installation, it is also important to consider whole life costs. These consist of the initial cost of the fan, energy costs, plant life expectancy, the cost of maintenance and other operational issues, and disposal costs.

MINIMISING MAINTENANCEMaintenance is required for fans, even if they are balanced and operating faultlessly, maintenance is required. For all larger fans this will include assessing the impeller structural integrity (inspection for cracks, excessive erosion or corrosion), checking and changing the oil.

AXIAL AUTO VARIABLE PITCHInspection of impeller, bearings, shaft seals and control system. Refurbish as necessary. Replacement of main bearings, blade support bearings, hydraulic actuator and AVP thrust blocks. This will not be required at every outage as the operating life of each of these components will vary depending on the fan speed and duty. The Variax® Axial Fan has a number of features to minimise outage time for maintenance and to allow extended operation. Each individual blade is balanced and the blades can be replaced on site without rebalancing of the complete rotor. The diffuser is mounted on travel rails and is displaceable. Blade replacement is possible through an inspection cover in the impeller casing, and impeller overhauls can be made without dismantling the fan casing.

The blade bearings use oversize balls to create a larger contact surface and the greater load-carrying capability extends bearing life.

CENTRIFUGALInspection of impeller, bearings, shaft seals and control system. Refurbish as necessary.

MIXED FLOWInspection of impeller, bearings, shaft seals and control system. Refurbish as necessary.

For providing easy access when inspecting the impeller and main bearing assembly. The impeller can be inspected from inside the fan, and there is an access door to the inner tube of the fan diffuser end.

Service intervals can be increased to between 4 and 6 years.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN MAINTENANCE

Page 58: Howden GlobalMining Australia

56

CHILLERS

HOWDEN OFFERS TURNKEY AMMONIA CHILLER PLANT INSTALLATIONS, INCLUDING CIVILS WORK, PERIPHERAL PLANT, AND ELECTRICAL AND CONTROL SYSTEMS, FOR MINE COOLING REQUIREMENTS.

Our chiller plants are custom designed to the specifications of each client and can be adapted to the requirements of individual country or jurisdictional requirements.

Howden chillers are based on the Howden WRV range of screw compressors, of which more than 20 000 are in service worldwide. They are employed in conjunction with proven type heat exchangers, pressure vessels and cooling towers. All pressure components are built and certified to relevant statutory and industry codes.

Output control is typically Programmable Logic Controller (PLC) based and integrated with the overall mine cooling requirement to optimise system efficiencies.

Howden chiller plants are designed and developed in-house, and packaged units are based on simplified refrigeration processes, thereby eliminating the need for economisers or gearboxes for duties up to 9,5MW(R). No refrigerant pumps or refrigerant

pump-out facilities are required and the refrigeration process design eliminates the possibility of the corrosion of the internal components of the plant.

Typical ammonia water chiller performance data for mine cooling applications, based on an evaporating temperature of -1,5˚C and a condensing temperature of 30˚C, are:

Ammonia is an efficient natural refrigerant with zero Global Warming Potential (GWP) and long-term availability.

For enhanced safety, Howden ammonia chiller plants are built to strict industry and statutory codes to ensure plant safety. Plant design is such that safety relief valves should not discharge under any condition, except possibly fire. The ammonia leakage detection and emergency shut-down process is automated, and each plant is sectionalised so that only part of the ammonia charge is safely released via scrubbers in the event of catastrophic failure.

BULK AIR COOLERS Howden can supply large horizontal bulk air coolers (BACs), with capacities of up to 15MWR, for pre-cooling mine downcast air. Our unique counter-flow design results in a higher thermal efficiency and smaller footprint than conventional cross-flow designs.

Refrigeration Cap kW(R)

Absorbed Power kW(E)

321/193 4900 850

321/220 5800 990

365/165 6100 1110

365/193 7200 1300

510/165 8500 1430

510/193 9500 1600

Page 59: Howden GlobalMining Australia

57

UPGRADING FANS:INCREASING OUTPUTThroughout the life of a plant it is possible that a fan will be required to compensate for a change in operating conditions, perhaps because of a need to increase process output (greater flow) or due to changes in the plant layout (greater pressure drop).

Increased output will mean increased absorbed power and unless the original driver has substantial design margins built in, it may have to be replaced with a higher rated machine. Noise generated by the uprated fan will also increase, roughly in proportion the increase in shaft power.

INCREASE THE FAN SPEEDIncreasing fan speed is a very effective way of improving fan output. It is however only possible to increase output in this way if the impeller can accept the higher stresses. Finite Element Analysis will be able to assess the basic strength of the impeller and its residual life operating under the new conditions.

GEARBOX/BELT DRIVEIf the fan already has a gearbox or belt drive installed, then it is a relatively simple matter to replace the gearbox internals, or the pulleys with a ratio which produces the desired fan speed. Otherwise a gearbox or belt drive will need to be installed, provided sufficient space is available.

HIGHER SPEED MOTORA new electric motor running at one pole-speed higher than the existing one will provide a step in output. This will probably be excessive. However the fan can be throttled back by the fan control system to provide the desired output.

MODIFY THE SYSTEMReducing the pressure drop in the system could balance the addition of extra pressure drop elsewhere or allow a fan to produce a compensatory

increase in flow. A particularly important area is the ducting immediately upstream of the fan inlet. A layout which induces spin in the gas flow, or biases the flow to one side of the inlet can reduce the fan output considerably.

TIP THE BLADES (CENTRIFUGAL FANS ONLY)A modification to the blade tips can increase the pressure generated by a centrifugal fan. This can be achieved either by increasing the length of the blade (tipping) or by changing the shape of the blade at the fan outer diameter (wedging). As impeller stresses will be increased due to the extra load, a thorough inspection of the fan and analysis of its strength must be carried out before any modifications are made.

REPLACE THE ROTOR (CENTRIFUGAL FANS)Replacing the rotor with a new one designed for the new operating conditions can be a cost effective method of changing output. There is a limit imposed by the casing on the maximum size of impeller which can be accepted. Modifications to the casing ‘cut-off’ and to the inlet cones will almost certainly be required.

REPLACE THE ROTOR (AXIAL FANS)Within the bounds of the fan tip diameter, a new impeller can be fitted to an axial fan with a different size of hub. A larger hub will increase the pressure that the fan generates.

INSTALL A NEW FANIn instances involving a substantial increase in output a new fan may be the only option. Whilst expensive, the through life cost analysis will indicate if the benefits are worthwhile. The space available may dictate that a centrifugal fan can only be replaced by a centrifugal fan. Although it may be possible to replace an axial fan with a mixed flow fan and vice versa.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN INCREASING OUTPUT

Page 60: Howden GlobalMining Australia

58

PORTABLE COOLING PLANT

HOWDEN OFFERS CUSTOM-DESIGNED MINE AIR COOLING PACKAGES READY FOR INSTALLATION, EITHER AS UNDERGROUND OR SURFACE UNITS.

Each Howden screw compressor is supplied as a skid-mounted package, precisely tailored to the requirements of each customer and application, and including a compressor, compressor driver, oil separator, condenser and evaporator.

Plant configurations allow for many variations in design, including single or multiple compressors, electric motor or gas engine drivers, air or water-cooled condensers and plate, kettle, shell and tube, or shell and plate evaporators. The process chosen will optimise the capital and power cost within the design parameters.

Howden’s mine air cooling packages are equipped with the required components and systems, ready for rapid connection on site.

A complete turnkey service is offered, starting with initial consultation, commissioning and extending to full aftermarket care.

Page 61: Howden GlobalMining Australia

59

FAN PRESSURESThe pressure rise across a fan can be defined in a number of ways.

The most useful definition is Fan Total Pressure which is the difference between the total pressure at the fan outlet and the total pressure at the fan inlet. This is Fan Pressure as defined in ISO 5801 for the conditions found in most systems applications (M<0.15).

Fan Static Pressure is also used. This is the Fan Total Pressure less the fan discharge velocity pressure. Historically this has been used when the fan is the last component in the system and the fan supplier will control the velocity pressure discharged.

The fan pressure can also be defined as Static Pressure Rise. This is the difference between the static pressure at the fan discharge and the static pressure at the fan inlet. For this definition to be of any use the system designer must know what these areas are as different fan suppliers offer different geometries for fan inlet and discharge ductwork. The required Static Pressure Rise will need adjustment to compensate for any mismatch between the fan inlet and discharge areas and the proposed system ductwork.

The total pressure at any point in a flow system is the sum of the static and velocity pressures. This fact must be kept in mind whenever static pressures are specified as any change in flow area will affect the velocity and hence the static pressure component. For this reason the use of Fan Static Pressure or Static Pressure Rise should be discouraged as both are dependent on the flow passage areas and can lead to misunderstandings regarding the required fan duty.

VIBRATION MEASUREMENTFan vibration can be measured using either:

SEISMIC INSTRUMENTSThese are instruments that measure the vibration relative to the ground. They are the accelerometers and velocity transducers among others, and can be seen attached to bearing housings, or

PROXIMITY PROBESThese are used for measuring the shaft vibration relative to the housing. Vibration levels for new machines, alarm and trip can be obtained from the manufacturer, and all alarm and trip levels should not be more than the standards specify.

Eddy current probes are being applied to fans and are applied to blowers. They are the only means of correctly monitoring machines where the bearing oil film is much softer than the support. Hence they are predominantly used for machines operating above 3000rpm. In addition, such probes are sensitive to local shaft effects such as out of roundness or even different electrical properties. These effects are known as mechanical or electrical run-out and must be taken into account by the vibration systems electronic system in an attempt to cancel their influence. As such shaft proximity vibration probes should be treated with caution when applied to fans running below 1500rpm.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

FAN PRESSURE

Page 62: Howden GlobalMining Australia

60

FURNACES AND INDUSTRIAL COMBUSTION

HOWDEN MARKETS A WIDE RANGE OF INDUSTRIAL FURNACES AND BURNERS WHICH ARE SUPPLIED AS TURNKEY PACKAGES DESIGNED TO THE CUSTOMER’S REQUIREMENT.

INDUSTRIAL FURNACESOur industrial furnaces can be supported by all types of firing – gas, oil or electricity – and can be supplied as complete systems for general plant requirements, dependent on the application and customer specification.

INDUSTRIAL COMBUSTIONBurners suitable for different customer-specified applications are produced. These include:

Kiln Burners – these systems number among the most fuel–efficient burners of their type available, and can be designed to fire oil, coal, gas, wood waste, producer gas or combination fuel.

Producer Gas/Solid Fuel Burner Systems – low calorific value gas or any combustible fines can be used to replace more traditional fuels. We engineer total systems for producer gas, blast furnace gas, agricultural waste fines and sawdust, as well as pulverised coal.

Air Heaters – Hot gas generation systems for thermal driers or any application requiring process heat.

HOWDEN KNOW HOW

ROTARY AIR HEATER BIDS

ASSESSING HEATER BIDSWhen assessing heater bids there are key items that need to be addressed: layout, duty, selection, performance.

LAYOUTEnsure that the inlet and exit flow profiles maximise heater performance and ensure good mixing of outlet gas. A vertical shaft arrangement is preferred in order to reduce cyclic stress. Give consideration to the need for more frequent replacement of cold end elements. Horizontal replacement eliminates the need to remove intermediate and hot-end baskets.

DUTYThere must always be a reasonable temperature difference between hot and cold streams for heat transfer to take place, thus the maximum temperature of the air leaving the preheater is limited by the temperatures of the air and gas

entering it. Typically there should be about 20-25˚C difference between gas in and air out temperatures.

SELECTIONHowden has a large number of element profiles, with different characteristics, available for use in air preheaters. The most appropriate elements are selected from an optimised range for each and every application.

Generally it is necessary to control the primary air temperature to suit varying coals and to control the metal temperature at the cold end of the preheater to keep corrosion and fouling within acceptable limits.

PERFORMANCEAir leakage can be calculated from either the difference in gas mass flow entering and leaving the preheater, or from the difference between diluted and undiluted gas temperatures. Many air preheater

designs develop leakage drift, where air leakage increases substantially over a period of time. Margins have to be added to the draught fan duties to account for this. The advanced VN sealing system supplied by Howden does not exhibit leakage drift, resulting in lower fan margins and reduced capital cost.

ROTATING HOOD AIR PREHEATERSThe rotary hood air heater is an alternative to the Ljungström design. The rotor (stator) is stationary and the ducts (hoods) rotate to create the alternative air and gas flows. This requires a multitude of sealing and movable parts that are prone to wear and damage unlike the Ljungström design does not need contact seals between the rotating and stationary parts, resulting in lower leakage and maintenance.

The rotary design can maintain low leakage but requires short, frequent skilled maintenance and replacement spares. Howden companies

Page 63: Howden GlobalMining Australia

61

HOWDEN PRODUCTS

FURNACE OFF-GASRECOVERY PLANT

HOWDEN SUPPLY TURNKEY FURNACE OFF-GAS RECOVERY SYSTEMS FOR PURPOSES OF ENERGY RECOVERY AND GAS SYSTEM PRESSURE BOOSTING.

The main purpose of an off-gas recovery and distribution system is to capture off-gas from smelter furnaces and to distribute the off-gas to various users on the plant. The gas from the furnace is collected at low pressure and boosted for supply to the various users at their specified required flows and pressures.

Our off-gas distribution system utilises liquid ring compressors to increase the pressure to the desired user requirement, where it is used as an alternative to fuel gas and electric power, thereby reducing operating costs. User burners are equipped to accommodate either fuel gas or furnace off-gas. Typical applications are the pre-heaters at each furnace, slag treatment plant

burners, metal treatment burners, or any other plant burners equipped with dual gas burners.

Due to the potential hazards associated with carbon monoxide (CO gas), plant design and control philosophies include safety devices and operational checks and procedures recommended for safe plant operation.

manufactured several dozen of these large rotating hood heaters, and if a total replacement to a modern Howden Ljungström air preheater is impossible Howden has the skills and expertise do actively service, supply spares, upgrade and provide all “solutions” engineering.

WHEN TO REPLACE ELEMENTSThe decision to replace elements is generally based on a visual inspection, which involves identifying:

• Relaxation of elements

• Decrease in thickness

• Overall corrosion and surface loss.

However, as most plants have limited access to inspect the heater element condition, once evidence of material loss is seen, accelerating deterioration will follow, this should be taken

seriously and plans made to replace the baskets at the next outage window, even if there might be some extra operation hours left.

Deterioration of the elements generally follows the following pattern:

Firstly the element plates reduce in material thickness. Thereafter the profile loses its structural strength that in turn allows deformation of the element profile and consequently loosens the original basket compression. The loose plates vibrate continuously, due to air and gas passing and soot blowing, which then causes fatigue and consequently breakouts of large element plate pieces. The breakout process continuously accelerates which causes more severe vibration to the point of total basket disintegration.

In addition, cold end baskets often suffer severe corrosion, which causes, material thinning, cold spot

blockage, fouling and uneven material loss areas.

The subsequently uneven flow and heat exchange causes reduced thermal efficiency and high flow volume through low-pressure resistant areas and low flow volume through high-pressure resistant areas.

Consequently upper element layers and the surrounding rotor housing and seals experience premature accelerated high spot erosion and vibration damage and other upper layer areas suffer from accelerated cold spot corrosion which creeps upwards.

In general, boiler operation can adapt to gradual heater thermal efficiency changes within some limits with the consequence of efficiency reduction.

However, accelerated hot-end damage rapidly exceeds the limits.

Page 64: Howden GlobalMining Australia

62

ROTARY HEAT EXCHANGERS

HOWDEN IS ABLE TO APPLY MORE THAN 80 YEARS’ OF EXPERIENCE IN AIR PREHEATER DESIGN AND MANUFACTURE TO BOILER APPLICATIONS RANGING FROM LARGE 500 TON UNITS TO SMALL 5 TON PACKAGES.

This enables us to customise air preheater solutions for mines and process plant needing to generate their own power. The result is a compact, cost-effective and reliable solution for heat recovery and, where necessary, flue gas desulphurisation systems.

The design principle of the Howden rotary air preheater is to allow hot gas to pass through a matrix composed of multiple metals plates (elements). The hot gas, usually at a temperature of 350˚C, passes across the surface of the metallic elements, raising the temperature very rapidly. As the rotor turns slowly, typically at one revolution per minute, the heated elements are transferred into the airside. Here cold air flows between the spaces formed by the element plates, extracting significant amounts of heat and raising the air temperature to 300˚C.

The vast quantity of heat transfer elements required is of a special form which promotes turbulence in the gas and air streams to maximise heat transfer without encouraging pressure drop in the air and gas stream.

We have developed a large range of elements, with differing thermal and pressure drop characteristics to match the application. Proprietary Howden sealing elements are used to separate the air and gas streams.

When handling large quantities of hot gas and cold air, this type of heat exchanger is the most efficient and compact available. The reason is that both surfaces of the element plates are used for heat transfer simultaneously, with the same plates, or heat transfer surfaces, being used in both the gas and air side of the rotary air preheater, which improves boiler efficiency by up to 10%.

Page 65: Howden GlobalMining Australia

63

ROTARY REGENERATIVE VS RECUPERATIVEThere are two main types of preheaters in boilers and steam generators – recuperative and regenerative.

For power plants and similar applications, a rotary regenerative heater will always be significantly smaller and lighter than a recuperator. The reason for this is simple. With a rotary regenerative type, both sides of the heat-transfer plates are used for active heat-transfer (either heat in or out), and the same plates are used in both sides of the heater. With a recuperator, only one side of the tube surface is used for the heat input, with the other side only being used for heat output. This means that a recuperator requires significantly more surface area than a rotary heater.

In addition, a rotary regenerative type, where the thermal energy is stored within the mass of the heat-transfer plates, build-up of dust on the surfaces will have a minimal effect on the heater’s thermal performance. This is due to the fact that the dust has mass and will also store thermal energy in much the same way that the metal in the heat-transfer plate will store energy.

With a tubular recuperator, the heat transfer is by conduction from the outside of the tube to the inside. That means that the heat transfer will take place through any dust layer before it can flow across the tube wall. In this type of heater the dust will be an additional resistance to heat transfer.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

ROTARY AIR HEATERS

Hot Air Hot AirHot Gas Hot Gas

Cold Air Cold AirCooled Gas Cooled Gas

Regenerative Recuperative

HeatTransfer

HeatTransfer

Heating Elementphysically moved

from air to gas

Heating elementphysically moved

from gas to air

EXAMPLES OF PACKAGE HEATERS

Page 66: Howden GlobalMining Australia

64

DUST SCRUBBERS

ENGART DUST SCRUBBERS NUMBER AMONG THE LEADING DUST COLLECTION SYSTEMS IN THE COAL MINING INDUSTRY AND IN OTHER ENVIRONMENTS WHERE AIRBORNE DUST IS A RISK TO HEALTH AND SAFETY.

The range offers an excellent combination of compact, robust design and economy. Engart can be mounted on a continuous miner underground, or in a ducted system on the surface for controlling dust at transfer points, coal silos or railcar tipping points.

Dust-laden air is drawn into the dust extractor and mixed with water at the impeller and in the chamber. The dust/air/water mixture is then drawn around the motor and then caught in a steel woven mesh which is continually washed by a multi-nozzle spray bank. The sludge is pumped away and dust-free air is exhausted.

Our products are sold and supported by experienced sales engineers who understand their products and are qualified to specify, install and service our Engart systems at site.

Whatever the task, Engart dust scrubbers attain unsurpassed levels of performance levels. Dust capture and scrubbing efficiencies of 99% of total dust are achieved.

Engart dust scrubbers have:

• High collection efficiencies

• Energy efficiency

• Low maintenance costs

• Robust construction

• Ease of operation

• A safe, flame-proof electric motor out of the air stream

• An anti-spark impeller track.

Page 67: Howden GlobalMining Australia

65

SELECTING THE CORRECT ELEMENTThe satisfactory performance of both rotary air heaters and gas heaters is greatly dependent upon the selection and use of the most appropriate design profile of heat transfer element for the chosen application.

Any particular element profile may appear to have an excellent combination of performance parameters. However the mechanical and dimensional integrity of the element pack must be maintained at the required level during manufacture, installation and subsequent operation. Otherwise, any element looseness would result in rapid fatigue damage to the pack, while uneven element spacing may compromise the element fouling characteristics.

Thermal and pressure drop performance have similar levels of importance. On-going element development activities invariably involve a continuous search for an element profile that produces either:

• The same thermal performance for a lower pressure drop or

• A better thermal performance for the same pressure drop and/or

• The achievement of either of the above objectives while using less total surface (i.e. at minimum weight and hence cost).

Such detailed differences between element geometries have been thoroughly researched and applied by Howden.

It is paramount to minimise the clean plate pressure drop in order to achieve either the lowest fan power (for new installations), or the maximum fan margin (for retrofits on existing installations). The next most important pressure drop parameter is the fouling resistance of the element. This may be considered to be the rate at which fouling and pressure drop drift might be expected to occur for any given set of adverse operating conditions. The final most important factor is the ease of cleaning of the profile

– both by means of conventional soot blowing and high pressure water washing.

With regards to thermal performance, the factor of primary importance is inevitably the ability to achieve the required thermal performance using the selected element profiles.

While original equipment might readily be designed to meet a given thermal performance with any selected combination of elements simply by making the heater deeper or larger, with retrofits in an existing heater, it can be even more important to try to achieve the maximum thermal performance within the existing volume of the heater. This is why the maximum thermal performance (for a given volume) is the next selection criterion. While this is a parameter or requirement that inevitably must be considered in any selection of original equipment or retrofit, in many cases, the retrofit of a combination of higher performance elements in an older unit can make this requirement slightly less stringent.

Equally in many installations it is also important that there is a suitable element metal temperature distribution through the depth of the rotor to minimise any dew point condensation phenomena straddling across two tiers of elements.

Minimum weight represents the least considered technical requirement, but from a commercial viewpoint, the element weight has a direct impact on cost, and must therefore always be considered.

Howden offers unrivalled advice in element selection, particularly where operating conditions have changed since the original elements were supplied, and can recommend alternatives to assist in optimising plant operation.

It is important to note that copied and wrongly manufactured element plates may very inefficient and/or and sensitive to blockage and fouling.

HOWDEN PRODUCTS

HOWDEN KNOW HOW

ROTARY AIR HEATER ELEMENTS

Mechanical &Dimensional

IntegrityMinimum

Pressure Drop(Clean Plate)

FoulingResistance

Ease ofCleaning

MinimumWeight(Cost)

SuitableElement MetalTemperatureDistribution

Maximum ThermalPerformance

(For given volume)

RequiredThermal

Performance

THER

MA

LFa

ctor

s of

dec

reas

ing

imp

orta

nce

PRESSU

RE D

RO

PFactors of d

ecreasing imp

ortance

OptimisedElementProfile

Page 68: Howden GlobalMining Australia

66

Page 69: Howden GlobalMining Australia

67

INDIVIDUALLY TAILORED SERVICES LIFETIME SUPPORT FOR ALL PRODUCTS

IN THIS SECTION

Howden Legacy Brands 68

Howden Mining Products Capabilities 70

Turnkey Installations 72

Lifetime Maintenance 74

Page 70: Howden GlobalMining Australia

68

WESTINGH OUSE FANSHOWDEN FANS

HOWDEN LEGACY BRANDS

AEREX® FANS

AERODYNE FANS

DONKIN BLOWERS

GODFREY BLOWERSHOWDEN SIROCCO FANS & HEATERS

JOY FANS

PHOENIX FANS

VENTILATEURS NEU FANS

VARIAX® FANS

CARTER FANS

VOITH FANS

BURTON CORBLIN COMPRESSORS

DAVIDSON® FANS

ENGART FANS

HOWDEN PROCESS COMPR ESSORS

MAJAX FANS

PITSTOCK FANS

TURBOWERKE MEISSEN FANS

VENTILATOREN SIROCCO FANS

BERRY FANSBUFFALO® FANS

JAMES HOWDEN (BELOW) WAS NOT ONLY AN INNOVATOR AND INVENTOR WHO REVOLUTIONISED THE WAY THE WORLD THOUGHT ABOUT GENERATING POWER, HE WAS ALSO AN INTERNATIONAL BUSINESSMAN WHO FORGED NEW RELATIONSHIPS AND PARTNERSHIPS WITH LIKE MINDED ENGINEERS AND BUSINESSMEN AROUND THE WORLD.

As early as the 1920s his negotiations with A/B Ljungströms Angeturbin (ALA) resulted in the formation of a joint venture company – Howden Ljungström Preheaters (Land) Limited based in Glasgow and Wellsville.

This company developed and manufactured the rotary air preheater which remains a prevalent technology in air and gas handling, and a key product in the Howden portfolio. James Howden & Co Ltd also licensed the screw compressor from SRM in Sweden and became the first company to commercialise the technology.

This international vision has been part of Howden’s strength over the last 160 years and throughout this time we have created, partnered, developed and acquired many well-known technologies, companies and/or brands in air & gas handling.

Customers who own legacy branded products can rely on Howden to provide comprehensive and professional sales and service support throughout the life of the equipment.

Page 71: Howden GlobalMining Australia

69

WESTINGH OUSE FANS GREEN FANS®

HOWDEN FANS

INDIVIDUALLY TAILORED SERVICES

CANADIAN BLOWER

BUFFALO FORGE®

AMERICAN BLOWER®

FANTECNIC FANS

GODFREY BLOWERSHOWDEN SIROCCO FANS & HEATERS

JOY GREEN FANS

WOLF FANS

MEISSEN FANS

SIROCCO® FANS

STURTEVANT® FANS

JAMES HOWDEN FANS

AIRTECH FANS

DONKIN FANS

WHEELER FANS

HOWDEN PROCESS COMPR ESSORS

POWERMAX FANS

SHELDON FANS

TAILARES SANCHEZ LUENGO (TSL) ELEMENTS

NEU FANS

Howden® is a registered trademark of Howden Group Ltd. All rights reserved.

Variax® is a registered trademark of Howden Denmark. All rights reserved.

Sturtevant®, Green Fans®, Buffalo® Fans, Davidson®, Sirocco®, Buffalo Forge®, Aerex®, and American Blower® are registered trademarks of Howden North America Inc. All rights reserved.

All other trademarks are the property of their respective owners.

Page 72: Howden GlobalMining Australia

70

HOWDEN MINING PRODUCTS CAPABILITIES

HOWDEN HAS A WORLDWIDE FOOTPRINT THAT ENABLES THE COMPANY TO SUPPORT MINING CUSTOMERS WHEREVER THEY ARE LOCATED ON THE GLOBE.

All aspects of the value chain are catered for in a well-balanced mix starting at the engineering concept and stretching to the supply and support of the finished product.

Our core research and consultancy arm is based at our headquarters in Renfrew in the United Kingdom. These facilities are staffed by specialists in disciplines such as creep analysis, advanced acoustics and Computational Flow Dynamics (CFD). Efficient, modern communication brings this sophisticated technical consultancy service to other Howden companies, and to Howden customers, ensuring they always have access to optimised, efficient, durable equipment and solutions for the mining and mine-related industries.

We have companies in 17 countries on six continents; providing superior engineering and manufacturing, backed by a comprehensive network of operational, sales and service personnel, all in close proximity to virtually all the world’s major metals and minerals deposits. Through these companies our customers are able to access our market-leading technologies, and comprehensive local knowledge and insight from our experienced engineers and site service personnel. Wherever a new mine or plant is located, Howden invariably delivers the best possible solution to site, no matter how remote the location. Rapid local support is also available for sophisticated solutions on which 24/7 production schedules are dependent.

This worldwide network ensures that multi-national resources companies can be confident that Howden will remain their single, consistent and reliable global supplier of mine and mine-related engineered solutions; anywhere in the world their operations are located.

Howden’s global reach and applications experience over a wide range of products enable us to provide packaged solutions for any mission critical customer specification.

Page 73: Howden GlobalMining Australia

71

INDIVIDUALLY TAILORED SERVICES

Renfrew, Glasgow

New Philadelphia

Howden North America Inc.

Howden UK (Group headquaters)

Sao PauloHowden South America

Johannesburg

Howden Africa Holdings

BeijingHowden Hua

Moscow

SydneyHowden Australia

HaryanaHowden Air & Gas India Pvt. Ltd

HeidenheimHowden Ventilatoren

Howden LLC

HOWDEN’S MINING FOCUSED BUSINESS LOCATIONSHowden has engineers with extensive expertise of local customer requirements in each of the key global mining markets:

• Australia and South East Asia

• China

• Europe/Russia (FSU)

• India, Central Asia and Middle East

• North America

• South America

• Africa.

Page 74: Howden GlobalMining Australia

72

TURNKEY INSTALLATIONS

HOWDEN’S PROJECTS INVOLVEMENT STRETCHES BEYOND THE DESIGN AND MANUFACTURE OF WORLD-CLASS PLANT AND EQUIPMENT. WE OFFER A TURNKEY SERVICE THAT TAKES A PROJECT FROM CONCEPTUALISATION, THROUGH DESIGN AND MANUFACTURE, TO INSTALLATION AND COMMISSIONING.

The comprehensive Howden package includes customised engineering, manufacture, project management, supply, service solution engineering and site management service, to the satisfaction of the customer and local regulatory authorities.

ENGINEERINGSophisticated computer programs are used to examine multiple solutions for each application. Where required, feasibility studies, including commercial evaluations, are completed. Howden’s experienced professional mechanical and structural engineers use modern design techniques and systems such as Finite Element Analysis (FEA), Computer Aided Design (CAD) and Computational Fluid Dynamics (CFD) that ensure that all our products

perform to the highest specifications. The end result is custom-engineered products for each application, tested at specialised facilities using either full-size systems or scale models. We also have equipment for stress, acoustic and vibration measurement, and on-site performance testing can be conducted to internationally recognised standards.

MANUFACTURINGHowden equipment is manufactured to world class standards in its own factories, or at third party supplier facilities. Our factories are staffed by experienced teams with access to a decades-long institutional knowledge base that provides us with the capability to produce products with a proven track record. Procedures developed specifically to

suit the Howden product range are used to optimise efficiency and performance.

Established suppliers with proven quality records are registered on the Howden approved vendor list and their performance is regularly reviewed. Our sub-contractors are selected on the basis of their ability to deliver a quality product or service on time.

PROJECT CAPABILITYThe Howden project capability includes the supply of complete end-to-end solutions. This includes civil works and associated buildings, ductwork, main drive motors, electrical switchboards and control panels, instrumentation and condition monitoring. Major rehabilitation works are engineered and managed.

Page 75: Howden GlobalMining Australia

73

INDIVIDUALLY TAILORED SERVICES

OUR TURNKEY SERVICE INCLUDES:

• Site surveys, inspection and plant evaluation

• Planning and scheduling using the latest computer techniques

• Engineering, design, and drafting

• Procurement

• Negotiation and control of sub-contracts

• Manufacture, testing and supply of equipment

• Where appropriate, re-work of existing equipment

• Site management and supervision of erection and commissioning

• Plant noise level evaluations and solutions

• Performance testing and upgrading

• Failure investigation

• Fan system variable speed conversion evaluation and design

• Improvement in fan and blower reliability.

Page 76: Howden GlobalMining Australia

74

LIFETIME MAINTENANCE

OUR COMMITMENT TO SUSTAINABLE CUSTOMER SERVICE EXCELLENCE HAS BECOME PART OF OUR CORPORATE CULTURE. THIS EXTENDS TO SUPPORT FOR OUR EQUIPMENT THROUGHOUT ITS LIFETIME AT SITE AND REPRESENTS MORE THAN ONCE-OFF MAINTENANCE; EXTENDING TO INCORPORATE TOTAL PLANT MAINTENANCE OWNERSHIP AND, WHERE NECESSARY, ON-LINE ROUTINE MAINTENANCE WHERE DEDICATED TEAMS ARE PERMANENTLY PLACED ON SITE.

LIFETIME MAINTENANCE

• Planned routine and preventative maintenance

• Monthly check and cleaning/adjusting

• Minor overhauls

• Major overhauls (every five years)

UNPLANNED MAINTENANCE

• Emergency breakdown with a 24 hour response availability

• Overhaul at longer off-load periods on an 24 hour/round the clock basis

• Dynamic balance and laser alignment

• Off-site maintenance

• Overhaul equipment

SPARES SUPPLY

• Supply of all planned (routine or preventative) fan spares

• Supply of emergency spares

• Stock management of spares off or/and on site

SITE SERVICES

All Howden equipment and systems have operating lives of between 20 and 40 years, and beyond. Equipment in service for extended periods of time gets worn out, requiring refurbishment. In addition, over time systems and requirements change, meaning that existing equipment often needs to be made more efficient and productive.

We recognise this need, and constantly endeavour to upgrade our installed base of equipment to keep pace with evolving customer requirements and specifications. We offer our customers the option of:

• Re-builds to original specification and upgrade of any air and gas movement equipment to the equivalent of the latest technology

• Upgrade for different output and changed gas medium

• Performance upgrades

• Turnkey supply of design, material, site management, site installation

• Site surveys, inspection and plant evaluation

• Performance and function tests and the relevant problem solution/implementation.

Page 77: Howden GlobalMining Australia

INDIVIDUALLY TAILORED SERVICES

75

Page 78: Howden GlobalMining Australia

Howden Australia Unit 23, 38-46 South StreetRydalmereNSW 2116Australia Tel: + 61 2 8844 9100Fax: + 61 2 8844 9101E-mail: [email protected]

Howden Africa1a Booysens RoadBooysens 2091PO Box 9501Johannesburg 2000South Africa Tel: +27 11 240 4000 Fax: +27 11 493 0545Email: [email protected]

Howden Ventilatoren Stubentalstraße 44D-89518 HeidenheimGermanyTel: +49 7321 3520Fax: +49 7321 35230Email: [email protected]

Howden HuaSuite 12B01 Jinyu MansionNo. 129 Xuanwumen XidajieXicheng DistrictBeijing 100031, ChinaTel: +86 10 66419988Fax: +86 10 66410071Email: [email protected]

Howden LLC 127030 Russia,Moscow,Novoslobodskaya Str., 21Tel: +7 495 933 70 79Fax: + 7 495 933 70 79Email: [email protected]

Howden Air & Gas India Pvt. Ltd201 Centrum Plaza Building,Golf Course Road,Sector 53,Gurgaon, Haryana122002IndiaTel: + 91 124 424 1901Fax: + 91 124 4241902Email: [email protected]

Howden North America Inc. New Philadelphia Division338 South Broadway St.New Philadelphia, OH 44663Tel: +1 330-308-7000Toll Free: +1 800-431-4880Fax: +1 330-339-8210Email: [email protected]

Howden South AmericaAv. Osvaldo Berto, 475CEP 13255-405Distrito Industrial Alfredo RelaItatiba - SP - BrasilTel: +55 11 4487-6250E-mail: [email protected]

©Howden Group Limited. All rights reserved. 2013Howden and the flying H logo are registered trade marks belonging to Howden Group Limited.

ENGINEERING EXCELLENCE WORLDWIDE

Focusing on its global expertise in mining and primary processing plant, Howden delivers first class technology, project management and customersupport. Wherever our customers are located, a Howden office is close athand. With engineering, manufacturing and sales offices throughout theworld, we understand and satisfy local market needs.

www.howden.com

MINING FOCUSED BUSINESSES