Vaugh school of Agricultural Engineering & Technology

Presentation on

MIXING

Submitted to: - Presented by:-

Er. Dorcus Masih Akash Deep Srivastava

(Assistant professor) M.Tech Food Tech (F.E.)

I.D- 09MTFTFE010

Semester-IIIrd

Sam Higginbottom Institute of Agriculture, Technology & Sciences

(Deemed–to-be-University)

Allahabad

ROTAMETER

“A Rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through to vary, causing some measurable effect”.

History

The first variable area meter with rotating float was invented by Karl Kueppers in Aachen in 1908. This is described in the German patent 215225. Felix Meyer found the first industrial company "Deutsche Rotawerke GmbH" in Aachen recognizing the fundamental importance of this invention. They improved this invention with new shapes of the float and of the glass tube. Kueppers invented the special shape for the inside of the glass tube that realized a symmetrical flow scale. The brand name Rotameter was registered by the British company GEC Rotameter Co, in Crawley, and still exists, having been passed down through the acquisition chain: KDG Instruments, Solartron Mobrey, and Emerson Process Management (Brooks Instrument). Rota with their "Rotamesser" is now owned by Yokogawa Electric Corp.

But there are certain misconceptions regarding the invention of rotameter. Rotameter (Variable Area Meters) are named after ROTA, one of the European inventors of this flow principle in the beginning of the century. ROTA invented the rotating float, which is self-guiding and has less friction in the pipe so that a more precise measurement is possible. The rotameter is popular because it has a linear scale, a relatively long measurement range, and low pressure drop. It is simple to install and maintain.

Implementation

A rotameter consists of a tapered tube, typically made of glass, with a float inside that is pushed up by flow and pulled down by gravity. At a higher flow rate more area (between the float and the tube) is needed to accommodate the flow, so the float rises. Floats are made in many different shapes, with spheres and ellipsoids being the most common. The float is shaped so that it rotates axially as the fluid passes. This allows you to tell if the float is stuck since it will only rotate if it is free. Readings are usually taken at the top of the widest part of the float; the center for an ellipsoid, or the top for a cylinder. Some manufacturers may use a different standard, so it is always best to check the documentation provided with the device.

Note that the "float" does not actually float in the fluid: it has to have a higher density than the fluid, otherwise it will float to the top even if there is no flow.

Another Definition

NSWGR Rotameter

The New South Wales Government Railways constructed in 1903 a device for measuring the length of its lines of railway. That authority named the machine a Rotameter. It consisted of a four-wheel trolley with an additional large fifth wheel which traveled along the running surface of the rail. Its last recorded use was in the 1920s. Rotameter offer a very low cost, easy to install solution to flow measurement. Once considered as only a water or air flow meter, rotameter is now world proven in applications such as industrial gases, viscous/non conductive chemicals, steam and fuels.

Basic Flowmeter Principles How They Work

Flowmeters are used in fluid systems (liquid and gas) to indicate the rate of flow of the fluid. They can also control the rate of flow if they are equipped with a flow control valve.

Rotameters are a particular kind of flowmeter, based on the variable area principle. They provide a simple, precise and economical means of indicating flow rates in fluid systems.

This variable area principle consists of three basic elements: A uniformly tapered flow tube, a float, and a measurement scale. A control valve may be added if flow control is also desired.

In operation, the rotameter is positioned vertically in the fluid system with the smallest diameter end of the tapered flow tube at the bottom. This is the fluid inlet. The float, typically spherical, is located inside the flow tube, and is engineered so that its diameter is nearly identical to the flow tube's inlet diameter.

When fluid —gas or liquid — is introduced into the tube, the float is lifted from its initial position at the inlet, allowing the fluid to pass between it and the tube wall. The greater the flow, the higher the float is raised. The height of the float is directly proportional to the flowrate. With liquids, the float is raised by a combination of the buoyancy of the liquid and the velocity head of the fluid. With gases, buoyancy is negligible, and the float responds to the velocity head alone. As the float raises, more and more fluid flows by the float because the tapered tube's diameter is increasing. The float moves up or down in the tube in proportion to the fluid flowrate and the annular area between the float and the tube wall. The float reaches a stable position in the tube when the upward force exerted by the flowing fluid equals the downward gravitational force exerted by the weight of the float. A change in flowrate upsets this balance of forces. The float then moves up or down, changing the annular area until it again reaches a position where the forces are in equilibrium. To satisfy the force equation, the rotameter float assumes a distinct position for every constant flowrate. Ultimately, a point is reached where the flow area is large enough to allow the entire volume of the fluid to flow past the float. This flow area is called the annular passage. The float is now stationary at that level within the tube, as its weight is being supported by the fluid forces which caused it to rise. This position corresponds to a point on the tube's measurement scale and provides an indication of the fluid's flow rate. This can be easily explained by the fig.1 given below.

The volumetric flow rate in accordance with the tapered tube diamter given by:

One way to change the capacity, or flow range, of a rotameter is to change the float material, and thus its density, while keeping the flow tube and float size constant. Floats which are made from

less dense materials will rise higher in the tube and therefore will yield lower flow capacities for the same diameter flow tube. Floats made from more dense materials will raise less thereby yielding higher flow capacities.

Fig. 1 Schematic representation of rotameter flow

Another way to change the capacity is to change the diameter of the flow tube and the size of the float.

Selecting The Right Flowmeter SizeThere are certain factors which affect the measurement of a fluid's flow rate with a rotameter. The fluid's temperature, pressure and specific gravity all impact gas flow measurements.

Flow capacities (ranges) for the flowmeters for air at standard conditions - 14.7 psa (101.3 KPa Abs) and 70°F (21°C) are described below. Sizing a meter for a gas other than air, or for specific application pressure and/or temperature, requires the determination for the equivalent flow capacity in air at standard conditions. Once determined, the flow capacity tables can be applied directly.

Table 1 provides correction factors for gases other than air at standard conditions. To estimate which flow tube should be purchased when measuring the flow of a gas other than air, multiply the flow rate desired by its factor below to find the air flow equivalent. The flow tube whose range (capacity) covers this flow rate should be the one purchased. Be sure to keep units consistent. Air Equivalent= Gas Flow Rate Desired x Factor. These factors assume standard operating conditions. Temperature 70°F/21°C; pressure 14.7 psa (101.3 K Pa Abs).

Gas Factor   Gas Factor   Gas Factor

Acetylene 0.95 Halocarbon-11 2.18 Hydrogen Chloride

1.13

Air 1.00 Halocarbon-12 2.05 Hydrogen Sulfide 1.08

Ammonia 0.77 Halocarbon-13 1.90 Isobutane 1.42

Argon 1.18 Halocarbon-13B

2.27 Isobutylene 1.39

1-3 Butadiene 1.37 Halocarbon-14 1.74 Methane (Natural Gas)

0.75

Butane 1.42 Halocarbon-21 1.89 Methyl Fluoride 1.09

1-Butene 1.39 Halocarbon-22 1.73 Monomethlamine 1.04

Carbon Dioxide

1.23 Halocarbon-23 1.56 Neon 0.83

Carbon Monoxide

0.98 Halocarbon-113

2.54 Nitrogen 0.98

Chlorine 1.57 Halocarbon-114

2.43 Nitrogen Dioxide 1.60

Cracked Ammonia

0.54 Halocarbon-116

2.18 Nitrous Oxide 1.23

CycloPropane 1.21 Halocarbon-115

2.31 Oxygen 1.05

DiFluoroethane 1.51 Halocarbon-142B

1.86 Propane 1.23

Dimethyl Ether 1.26 Halocarbon-152A

1.51 Propylene 1.21

Ethane 1.02 Helium 0.37 Sulfur Dioxide 1.50

Ethylene 0.98 Hydrogen 0.26 Sulfur Hexafluoride

2.25

Note: Flowmeters calibrated at standard conditions with a valve on the inlet, readings on the tube are correct provided that the outlet pressure is close to atmospheric. When the valve is on the outlet, readings are correct if the inlet gas pressure is equal to the pressure for which the tube was calibrated.

Depending upon the model, a flow-meter's measurement scale can be either direct reading or in reference scale units.

Direct reading tubes are straightforward. The measurement scale on each of these tubes reads actual flow at standard conditions in a choice of English or Metric units.

Reference scale tubes, on the other hand, provide a uniformly calibrated scale in arbitrary millimeter (mm) units. Obtaining actual flow rates with these tubes requires the use of a reference scale flow correlation table (available from Matheson) which relates the mm scale

reading to an actual flow rate. Reference scale tubes are useful when measuring flow rates for gases other than air and/or for non-standard conditions.

Flowmeter Calibration And Services

There are many formulas available, which calculate the flow of a fluid through a variable area flow-meter for which it is not calibrated. Moreover, these equations are used to generate correction factors for correlating other fluid flows to some known calibration, as shown in Table 1.

Matheson has conducted extensive experiments to determine the accuracy of these mathematical formulas. At best, calculated values estimate flow rates to about ±5% accuracy. If require greater accuracy, it will be necessary to calibrate the flowmeter with the actual gas, or at the particular conditions of temperature/ pressure.

Types of Rotameters-

1. Glass-tube rotameters: With a tapered metering tube made of a borosilicate glass, it is referred to as a “general purpose rotameter”. Because the float is normally visible in the tube, the meter shows the flow rate readings directly on scale graduations on the glass surface.

Low capacity glass tube meters are generally used in purge systems, where they are called are purgemeters.

Glass-tube rotameters are generally used for simple but reliable indication of flow rate with a high level of repeatability. Alarm contacts can be easily added to provide high/or low-flow signals, in which the contact is activated as the flow rate either drops below or rises above the set point.

Float with PTFE Ring avoids glass to metal contact and minimizes possibility of Glass Tube breakage

2. Metal tube rotameters: These devices, also known as armored meters, are designed for applications where the temperature or pressure exceeds the limits of glass tubes. Flow rate is indicated by a pointer on an indicating scale by means of magnet inside the float, magnetically linked to the pointer. Designed for indication only, metal tube meters require no external source of electric power. They may also be specified in applications requiring

remote transmission of the measured flow rate, a feature not generally available with glass tube rotameters.

Metal tube rotameters

3. Plastic tube rotameters: Plastic tube rotameters can be an entirely suitable, a very cost- effective alternative to glass and metal tube meters for a wide variety of fluid measurements. It is made of a single piece of clear acrylic that is practically unbreakable for most industrial-process applications. Often used as a purgemeter, this type is a low cost, reliable solution for most OEM applications.

Plastic tube rotameters

4. Purgemeters: A major class of rotameters. According to the ISA, “a purgemeter is designed to measure small flow rates of liquids and gases used for purging measurement piping”. They facilitate setting and accurately controlling the low flow rates involved. For water, the rate is typically well under 1 gpm and for air it is <2 scfm.

Advantages -

1- Sustained high repeatability: Since the flow rates moves freely in the metering tube without friction, thus attains high repeatability and maintains it over years of service.

2- Wide range ability: A ratio of 10:1 from maximum to minimum flow rate is typical. This means that minimum flow rate as low as 1/10 of the maximum flow rate can be measured without impairing the repeatability.

3- Linear scale: Because area variation is the measure of flow rate, the calibration curve is practically a straight line. This means the meter will be a linear scale. You can therefore read flow rate with the same degree of accuracy throughout the entire range.

4- Low pressure loss: Because the area between the float and the tapered tube increases with flow rate, pressure drop across the float is low and relatively constant. This reduces pumping costs.

5- Readily corrosion proofed: Because of its design simplicity, a rotameter can be economically constructed of highly corrosion-resistant materials. It can therefore measure fluid flows that no other type of meter will handle with continued success.

6- Easy to install and maintain: The inherent simplicity of design makes the rotameter easy to install and maintain. It mounts vertically in the pipe without pipe-taps, connecting lines, seal pots or valves or requirements for a straight run of pipe upstream or downstream as is necessary with a dp transmitter, nor is there a need to keep such parts free of foreign matter.

7- Measure very low flow rates: Liquid flow rates down to 1 m/pm and equally low gas flow rates can be measured.

8- Needs no electric power: The simple indication of flow rate locally requires no connection to an electric power source and hence, make explosion proofing unnecessary where flammable fluids may be present.

9- Easily converted to measure different fluids: A model installed for service on one fluid can be recalibrated to measure another, taking into account its specific characteristics.

Disadvantages-

Due to its use of gravity, a rotameter must always be vertically oriented and right way up, with the fluid flowing upward.

Due to its reliance on the ability of the fluid or gas to displace the float, graduations on a given rotameter will only be accurate for a given substance at a given temperature. The main property of importance is the density of the fluid; however, viscosity may also be significant. Floats are ideally designed to be insensitive to viscosity; however, this is seldom verifiable from manufacturers' specifications. Either separate rotameters for different densities and viscosities may be used, or multiple scales on the same rotameter can be used.

Rotameters normally require the use of glass (or other transparent material), otherwise the user cannot see the float. This limits their use in many industries to benign fluids, such as water.

Rotameters are not easily adapted for reading by machine; although magnetic floats that drive a follower outside the tube are available.

Rotameter Flowmeter Selection-The things to be checked while selecting a rotameter are:

Minimum and maximum flow rate for the flow meter. Minimum and maximum process temperature. Size of the pipe. Accuracy Having a valve to regulate the flow. Back pressure. The maximum process pressure.

Other types of Rotameters-

1. Liquid Rotameter-Made entirely of PTFE, PFA, and PCTFE, the Model FL-10 liquid flow meter is excellent for high-purity flow measurement applications or use with corrosive liquids. These flowmeters are available with a standard valve to monitor and control flow or without a valve to just monitor flow. Flow meters are individually tested on a Mass Spectrometer Leak Detector and certified to a leak integrity rating of 1 x 10-7 sccs Helium or better.

The specifications of liquid rotameter are as follows:

SPECIFICATIONS

Scales: 0 to 10 markingsAccuracy: ±5% of full scaleMaximum Temperature: 121°C (250°F)Maximum Pressure: 100 psig (6.7 bars)Leak Integrity: Individually, leak tested and certified to a rating of 1 x 10-7 sccs of HeliumMaterials of ConstructionTube Shields: PolycarbonateFlow Tubes: PTFE PFAFloats: PTFEWetted Parts: PTFE end fittings. PCTFE guide rodsDimensions

Low Flow: 144 L x 32 mm O.D. (5-11/16 x 1-1/4")High Flow: 267 L x 51 mm O.D. (10-1/2 x 2")

2. High Accuracy Shielded Rotameter-

These calibrated and correlated rotameters for the laboratory are available with all-plastic shields. The shields confine fluid contact to the FKM or PTFE inserts polypropylene and the glass tube. The polycarbonate shield makes it possible to use the rotameter under pressurized systems or in conditions where glass cannot be exposed. As with the corresponding unshielded rotameters, these units are available in five sizes to cover the full range of flows normally encountered with spherical floats.

3. General Purpose Rotameter-

FL-1300 series rotameters are supplied with an easy-to-read 65 mm (2.6") scale. The FL1400 series features a large, easy-to-read 150 mm (5.9") scale, with correlation charts for air and water flow measurement applications. The integral flow controller (for both the FL-1300 and FL-1400 series) maintains a set flowrate when upstream line pressure varies.

SPECIFICATIONS Metering Tube: Borosilicate glass Float: 316 stainless steel End Fittings: 316 SS (standard) Chrome-plated brass (optional) O-Rings and Tube Packing: FKM-A (316 SS fittings); neoprene (brass fitting) Max. Pressure: 13.8 bar (200 psig) up to 121°C (250°F) Connections: Horizontal female 1.4" NPT

4. High Flow Rotameter-

The FL-400A Series variable area flowmeters are used to measure the flowrate of liquids and gases in a variety of laboratory and industrial applications. These rotameters consist of a cylindrical float moving vertically in a glass tube with a tapered ID. As the flow through the tube increases, the float rises in the tube. By means of the scale on the tube and calibration charts, it is possible to obtain an accurate measurement of flowrate. By using floats of different densities, the maximum measurement range for the flow tube can be varied. The FL-400A Series rotameters are supplied with both glass and 316 SS floats.

5. Variable Area Rotameter-

SHIELDED FOR PRESSURIZED SYSTEMSThese rotameters, have heavy wall, precision-bored borosilicate glass metering tubes and are fully shielded against breakage, with end fittings of brass or stainless steel and aluminum side plates. In front, a clear plastic shield keeps the scale clean and easy-to-read, while an opaque white rear shield provides a background to aid in discerning the float position for accurate readings.

PANEL MOUNTING DESIGNThese rotameters are equipped with horizontal ports with NPT threads for easy panel mounting. The ports have external threads and are equipped with panel retaining nuts. No additional mounting hardware is required. Simply drill two holes 114.3mm (4.5") apart (center to center) for 65mm units or 223.8mm (8 13/16") apart (center to center) for 150mm units. Each hole should be 14.9mm (0.59") in diameter.

NON-RISING STEM NEEDLE VALVEThe 150 mm size flowmeters are also available with non-rising stem type needle valves for special applications. This 15-turn metering valve has superior flow rate control and is particularly well suited for use in chromatography applications. The sliding tapered needle mechanism virtually eliminates sticking or buildup due to foreign matter in the fluid stream, without variations or sawtoothing of the flow rate.

COMPACT 65 MM SCALEThese compact units feature ±10% of full scale accuracy and ±½% of full scale repeatability. They are ideal for applications involving purging, seal oil systems, bearing lubrication, and cooling water flow indication.

EASY-TO-READ 150 MM SCALEOMEGA's larger units feature 5% accuracy and ¼% repeatability. The scale has more divisions for higher accuracy, is easier to read, and causes less eye fatigue.

APPLICATIONSVariable area rotameters can be used in many applications, including industrial and laboratory situations. Some common uses include carrier gas flow and fuel flow in chromatography and coolant flow indication.

FLOW CONTROLControl the flow rate with the standard built-in control valve. Also available, as an option, is an integral flow controller. In addition, 150 mm scale units are available with the unique non-rising stem type needle valve.

WETTED PARTSStandard floats are 316 stainless steel, glass, and carboloy. Other wetted parts include the glass

mtering tube, PTFE float stops, brass, aluminum, or 316 SS end fittings, and Buna (with brass or aluminum construction) or FKM-A (with 316 SS construction) O-rings.

RATINGS AND SPECIFICATIONSThe maximum operating pressure is 13.8 bar (200 psig), at temperatures up to 121°C (250°F). The minimum flow rate at the rated accuracy is 10% of the maximum flow rate. All connections are 1/8" female NPT threaded.

6. ACRYLIC Rotameter -

Operating Principle:

ACRYLIC Rotameter is basically a variable area flow meter. The differential pressure across the annulus area is constant and the Flow rate is measured as a function of the position of annulus area. This area is displayed as the position of the ‘Float’ in terms of flow rate on the scale.

Standard features:

7. BY Pass Rotameter-

Operating Principle:

Easy to Maintain and replace

Suitable for in line installation

Heavy Duty Design With Full Visibility

Solid Acrylic Block

Accuracy : +/- 2% of full scale

Test Presure - 10 Kg / cm²

Measuring span - 1:10

Linear scale

Ranges between - 1-10 LPM to 1500-15000 LPM

Differential pressure ‘P’ is created in the main Flow by providing an Orifice plate in the main pipeline.

Because of this ‘P’ a branch of flow moves through By-Pass line provided across the orifice plate from up stream side to down stream side of the Orifice Plate.

Additional Range Orifice plate is provided in the By-Pass line which is designed such that flow through range Orifice plate flows in proportion with the flow through main orifice plate.

Hence by measuring the flow from By Pass line we can estimate the flow from Main Pipe line.

Standard features:

Easy to Maintain

On - Line Installation

Most Economical, Low Cost

Pipe Size - 40 NB to 300 NB

For High Flow - 8M / Hr. To 1500M / Hr.

Two tone powder coated excellent finish

No threads, No leakage, Avoids corrossions

Rangeability - 1:10 , 2 : 10

Heavy duty design with maximum visibility

Various options for material of construction of wetted parts

Overview-

Rotameter:

A rotameter is mounted vertically with the narrow end at the bottom and the tube tappers into a wider top. The flow comes from the bottom and pushes the float inside the rotameter up to a point that the weight of the float is in balance with the force exerted by the flow. The annular area between the float and the tube wall is then related to the volume flow rate.

As long as the fluid speed is substantially subsonic (V < mach 0.3), the incompressible Bernoulli's equation applies.

where g is the gravity acceleration constant (9.81 m/s2 or 32.2 ft/s2), V is the velocity of the fluid, and z is the height above an arbitrary datum. C remains constant along any streamline in the flow, but varies from streamline to streamline. If the flow is irrotational, then C has the same value for all streamlines.

Applying this equation to a streamline traveling up the axis of the vertical tube gives,

where subscript a represents the position right below the float, b is the balanced point of the float, usually the top of the float, V is the flow velocity, p is pressure, and is the density. A shorter form of the above equationi is

where hf is the hight of the float or the distance from the bottom to the indicator of the float that depends on the float design.

From continuity, the volume flow rate at a is the same as the volume flow rate at b, i.e.,

, which implies

Please note that is the annular area between the float and the tube wall, not the whole cross section area at b.

Hence, the velocity Vb can be substituted out of the Bernoulli's equation to give,

The pressure drop is mostly resulting from the weight of the float

Where, the subscript f represents the float, Vf is the volume, Af is the cross section area, and

f is the density of the float.

Solving for the volumetric flow rate Q, we have

Ideal, inviscid fluids would obey the above equation. The small amount of energy converted into heat within viscous boundary layers tends to somewhat lower the actual velocity of real fluids. A discharge coefficient C is typically introduced to account for the viscosity of fluids,

C is found to depend on the Reynolds Number of the flow.

For a given design, the cross section areas Aa(z) and Ab(z) of the rotameter are functions of the hight z, and the geometry (hf, Af, Vf) and the density ( f) of the float are also known. If the density of the fluid is measured and the readout of the position (z) of the float in the rotameter is available, the volume flow rate Q can be calculated from this formula:

The mass flow rate can be easily found by multiplying Q with the fluid density ,

References

1. How Far is That? The Story of the NSWGR Rotameter Australian Railway History, September, 2007 pp333-343

Overview

Orange Peels, Newspapers May Lead to Cheaper, Cleaner Ethanol FuelScienceDaily (Feb. 21, 2010) — Scientists may have just made the breakthrough of a lifetime, turning discarded fruit peels and other throwaways into cheap, clean fuel to power the world's vehicles.

University of Central Florida professor Henry Daniell has developed a groundbreaking way to produce ethanol from waste products such as orange peels and newspapers. His approach is greener and less expensive than the current methods available to run vehicles on cleaner fuel -- and his goal is to relegate gasoline to a secondary fuel.

Daniell's breakthrough can be applied to several non-food products throughout the United States, including sugarcane, switchgrass and straw.

"This could be a turning point where vehicles could use this fuel as the norm for protecting our air and environment for future generations," he said.

Daniell's technique -- developed with U.S. Department of Agriculture funding -- uses plant-derived enzyme cocktails to break down orange peels and other waste materials into sugar, which is then fermented into ethanol.

Corn starch now is fermented and converted into ethanol. But ethanol derived from corn produces more greenhouse gas emissions than gasoline does. Ethanol created using Daniell's approach produces much lower greenhouse gas emissions than gasoline or electricity.

There's also an abundance of waste products that could be used without reducing the world's food supply or driving up food prices. In Florida alone, discarded orange peels could create about 200 million gallons of ethanol each year, Daniell said.

More research is needed before Daniell's findings, published this month in Plant Biotechnology Journal, can move from his laboratory to the market. But other scientists conducting research in biofuels describe the early results as promising.

"Dr. Henry Daniell's team's success in producing a combination of several cell wall degrading enzymes in plants using chloroplast transgenesis is a great achievement," said Mariam Sticklen, a professor of crop and soil sciences at Michigan State University. In 2008, she received international media attention for her research looking at an enzyme in a cow's stomach that could help turn corn plants into fuel.

Daniell said no company in the world can produce cellulosic ethanol -- ethanol that comes from

wood or the non-edible parts of plants.

Depending on the waste product used, a specific combination or "cocktail" of more than 10 enzymes is needed to change the biomass into sugar and eventually ethanol. Orange peels need more of the pectinase enzyme, while wood waste requires more of the xylanase enzyme. All of the enzymes Daniell's team uses are found in nature, created by a range of microbial species, including bacteria and fungi.

Daniell's team cloned genes from wood-rotting fungi or bacteria and produced enzymes in tobacco plants. Producing these enzymes in tobacco instead of manufacturing synthetic versions could reduce the cost of production by a thousand times, which should significantly reduce the cost of making ethanol, Daniell said.

Tobacco was chosen as an ideal system for enzyme production for several reasons. It is not a food crop, it produces large amounts of energy per acre and an alternate use could potentially decrease its use for smoking.

Daniell's team includes Dheeraj Verma, Anderson Kanagaraj, Shuangxia Jin, Nameirakpam Singh and Pappachan E. Kolattukudy in the Burnett School of Biomedical Sciences at UCF's College of Medicine. Genes for the pectinase enzyme were cloned in Kolattukudy's laboratory.

Flowmeter rotameter

Rotameter Glasstube rotameter FBC-acrylic rotametr

Common Specifications

Common specifications for commercially available variable area flowmeters are listed below:

 

Fluid Phase: Please refer to flowmeter selection for specific sub-categories

 Line Size: Mostly used in lines size 100 mm (4 inch) and below, but may go up to

2000 mm (80 inch) in line size or even for open channels.

  Turndown Ratio: 10 ~ 100 : 1

Top of Page

Score Phase Condition

 Gas   Clean 

 Liquid   Clean 

   Open Channel 

 Gas   Dirty 

 Liquid   Corrosive  

   Dirty 

 Steam   Saturated 

: Recommended

: Limited applicability

Pros and Cons

  • Pros:

  - Very low initial set up cost

  - Simple, robust

  - Low, nearly constant, pressure drop

  • Cons:

  - Moderate accuracy at best

  - Not suitable for low flow rate

  - Some variable area flowmeters can not be used in non/low gravity environments

  - Rotameters must be mounted vertically