Pumps presentation

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Pumps APPLICATIONS, COMPONENTS, TYPES, WORKING,

Transcript of Pumps presentation

Page 1: Pumps presentation

PumpsAPPLICATIONS, COMPONENTS, TYPES, WORKING,

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http://www.industry.siemens.com/topics/global/en/pumps

What are pumps? A pump is a device that moves fluid i.e. liquids or some time slurries by mechanical action. Pumps can be classified in to three major groups according to the method they use to move the fluid i.e. direct lift, displacement and gravity pumps.

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Applications or uses Pumps are used in almost every home as a domestic water suction device for a daily life use.

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Industrial applications Building Services - pressure boosting, heating installations, fire protection sprinkler systems, drainage, air conditioning

Industry and Water engineering - boiler feed applications, water supply (municipal, industrial), wastewater management, irrigation, sprinkling, drainage and flood protection

The Chemical and Process Industries - paints, chemicals, hydrocarbons, pharmaceuticals, cellulose, petro-chemicals, sugar refining, food and beverage production

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What Is an industrial pump? There are dozens of different industrial applications a several types of industrial pump designs to fit the requirements.

Centrifugal pumps are used often in industrial applications. These pumps use a rotating impeller to accelerate a fluid and increase its pressure. There are dozens of industrial centrifugal pumps including slurry pumps, chopper pumps, sewage pumps, vertical turbine pumps, axial flow pumps and more.

In addition, rotary and reciprocating positive displacement pumps are often used in industrial applications to move fluids at steady flow rates with high pressure. Specifically, screw pumps, progressive cavity pumps, lobe pumps, gear pumps, diaphragm pumps, and peristaltic pumps are considered industrial PD pumps.

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Components Pump is made of two major components

1) motor

The power source of the pump which drives the shaft. AC motors and DC motors are the most common power sources for pumps, but internal combustion engines (ICEs), hydraulic power, and steam power are other possibilities.

2) impeller

A rotating disk with a set of vanes coupled to a shaft. When the impeller rotates, it imparts energy to the fluid to induce flow. Flow characteristics of the pump vary widely based on the impeller design.

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Parts of a pump Housing/casing – The outer shell of the pump which protects most of the components from the outside elements. The casing of the pump should be of materials suitable to withstand the environmental conditions of the application (e.g. submersible pumps should be water and rust corrosion resistant

Shaft – The shaft connects the impeller to the motor/engine that provides power for the pump.

Volute – The inner casing that contains the impeller and collects, discharges, and (sometimes) recirculates the fluid being pumped. The materials used to construct the lining of the pump volute must be compatible with the handled media.

Bearing assembly – The mechanical support that allows continuous rotation of the impeller and is continuously lubricated.

Hub – Device attached to the bearing assembly which is the connecting point for the motor or engine.

Seal – Protects the bearing assembly from being contaminated by the pumped media. Some pump designs are sealless, meaning the pumping mechanism is completely contained within a pressurized volute chamber with static seals (e.g. gaskets or O-rings).

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Additional components Controllers – Used in conjunction with probes and sensors to provide operational information as well as automatic or manual control of different pumping functions.

Fittings and adapters – Parts which connect different system components (pumps, motors, pipe, hose, etc.) to one-another.

Mounting devices – Used to allow pumps to be mounted in different ways, such as on walls, on the ground, or on/near associated stationary equipment.

Pump motor adapters – mounting devices used to connect dissimilar motor and pump bolt configurations.

Probes and sensors – Used to measure liquid level, pressure, temperature, and other important system factors during system operation. Data from probes and sensors are sent to controllers or computers for system analysis or response.

Valves – Used to control flow within different parts of the system, including the pump inlet and outlet.

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Types of Impellers There are basic three types of impellers which are used for different work conditions

1) closed type impeller: open type impellers are used for clean water only. The impeller can clog if you pump solids or "stringy material". It's difficult to clean out these solids from between the shrouds and vanes

2) semi closed type impeller:these types of impellers are used for pumping liquid which may contain some small stringy material.

3) open type impellerthe open type impellers are used for liquid which may contain some solid bodies .The open impeller is less likely to clog with solids, but if it does, it is easy to clean.

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Classification of pumps

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Classification of pumps Pumps are classified in two types

1) Negative displacement pump/centrifugal

2) positive displacement pump

Negative displacement pumps or centrifugal:

A pump that uses an impeller to move water or other fluids.It produce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller.

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Types of negative displacement pumpAxial Propeller:An axial propeller is a common type of pump that essentially consists of a propeller (an axial impeller) in a pipe. The propeller can be driven directly by a sealed motor in the pipe or by electric motor or petrol/diesel engines.

Fluid particles do not change their radial locations since the change in radius at the entry and the exit of the pump is very small. Hence the name "axial" pump.

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Mixed Flow Pump: The Pump which moves fluid by both radial acceleration and lift and exits the impeller somewhere between 0 and 90 degrees from the axial direction. As a consequence mixed-flow pumps operate at higher pressures than axial-flow pumps.

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Positive Displacement Pumps:

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. The positive displacement pump operates by alternating of filling a cavity and then displacing a given volume of liquid. The positive displacement pump delivers a constant volume of liquid for each cycle against varying discharge pressure or head.

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Types of positive displacement pump

Reciprocating pumps:

It moves fluid by reciprocating motion of piston. It is often used where a relatively small quantity of liquid is to be handled and where delivery pressure is quite large. In reciprocating pumps, the chamber in which the liquid is trapped, is a stationary cylinder that contains the piston

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Rotary vane pump A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside of a cavity. As the rotor turns, fluid flows into the enlarging suction chamber until it is sealed off by the vane. The enclosed fluid is then compressed until the outlet valve opens against atmospheric pressure due to pressure difference fluid moves from higher to lower pressure.

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Positive VS Negative Displacement PumpFlow Rate and Pressure Head:

The Centrifugal Pump has varying flow depending on the system pressure or head

The Positive Displacement Pump has more or less a constant flow regardless of the system pressure or head. Positive Displacement pumps generally gives more pressure than Centrifugal Pump's.

Capacity and Viscosity:

In the Centrifugal Pump the flow is reduced when the viscosity is increased

In the Positive Displacement Pump the flow is increased when viscosity is increased

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Mechanical efficiencyChanging the system pressure or head has little or no effect on the flow rate in the Positive Displacement Pump

Changing the system pressure or head has a dramatic effect on the flow rate in the Centrifugal Pump

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Principle of Operations:Centrifugal Pump:

The impeller of such a pump is magnetically coupled with the motor, across a separation wall which is resistant to the fluid pumped. The motor drives a rotor carrying one or several pairs of permanent magnets, and these drag around a second pair of permanent magnets attached to the pump impeller.

Positive Displacement Pump:

The fluid moved by the pump in one cycle (one suction stroke and one discharge stroke) as the piston moves from its farthest left position to its farthest right position and then to farthest left position.

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Pump Efficiency:Pump efficiency is defined as the ratio of the power imparted on the fluid by the pump in relation to the power supplied to drive the pump. Its value is not fixed for a given pump.

Mathematically:

Pump efficiency = power output / power input

Where,

Q= Flow rate.

H= Head.

Pc= Power consumed.

Me= Motor efficiency.

Tl= Transmission loss.

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Advantages And Disadvantages:Advantage of Centrifugal Pumps:

As there is no drive seal so there is no leakage in pump.

There are very less frictional losses.

There in almost no noise.

Centrifugal pump have minimum wear with respect to others.

There is a gap between pump chamber and motor, so there is no heat transfer between them.

Because of the gap between pump chamber and motor, water cannot enter into motor

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Disadvantage of Centrifugal Pump:

Because of the magnetic resistance there is some energy losses.

Unexpected heavy load may cause the coupling to slip.

ferrous particles in liquid are problematic when you are using magnetic drive. This is because particle collect at impeller and cause the stoppage of pump after some time.

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Advantages of Positive Displacement Pump:

In general, positive displacement pumps are ideal for applications where a constant flow is needed.

They create medium to high pressure and are often an excellent way to pump oils and other viscous fluids.

Positive displacement pumps are also extremely useful for applications requiring a combination of low flow and high pressure. For example, to move fluids containing suspended or fragile solids.

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Disadvantages of Positive Displacement Pump:

Principally a source of pressure fluctuations, althoughthere are some that produce far less fluctuations than others.

In general more gland problems.

Dynamic problems with check valves when applicable

In general higher maintenance costs.

Need for safety relieve valve to protect the piping against exceeding the design pressure of the system.

Construction is in general more complex.24

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Any query