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 Size

There 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 1.13
Chloride
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- 2.27 Isobutylene 1.39
13B
1-3 Butadiene 1.37 Halocarbon-14 1.74 Methane (Natural 0.75
Gas)
Butane 1.42 Halocarbon-21 1.89 Methyl Fluoride 1.09
1-Butene 1.39 Halocarbon-22 1.73 Monomethlamine 1.04
Carbon 1.23 Halocarbon-23 1.56 Neon 0.83
Dioxide
Carbon 0.98 Halocarbon- 2.54 Nitrogen 0.98
Monoxide 113
Chlorine 1.57 Halocarbon- 2.43 Nitrogen Dioxide 1.60
114
Cracked 0.54 Halocarbon- 2.18 Nitrous Oxide 1.23
Ammonia 116
CycloPropane 1.21 Halocarbon- 2.31 Oxygen 1.05
115
DiFluoroethane 1.51 Halocarbon- 1.86 Propane 1.23
142B
Dimethyl Ether 1.26 Halocarbon- 1.51 Propylene 1.21
152A
Ethane 1.02 Helium 0.37 Sulfur Dioxide 1.50
Ethylene 0.98 Hydrogen 0.26 Sulfur 2.25
Hexafluoride

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 markings
Accuracy: ±5% of full scale
Maximum 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 Helium
Materials of Construction
Tube Shields: Polycarbonate
Flow Tubes: PTFE PFA
Floats: PTFE
Wetted Parts: PTFE end fittings. PCTFE guide rods
Dimensions
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 SYSTEMS

These 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 DESIGN

These 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 VALVE

The 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 SCALE
These 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 SCALE

OMEGA'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.

APPLICATIONS
Variable 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 CONTROL
Control 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 PARTS
Standard 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 SPECIFICATIONS
The 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:

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

7. BY Pass Rotameter-

Operating Principle:

 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/s 2 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 Fuel
ScienceDaily (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

 
Score Phase Condition

Line Size: Mostly  Gas   Clean 

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.
 Liquid   Clean 
  Turndown Ratio: 10 ~ 100 : 1
   Open Channel 

Top of Page
 Gas   Dirty 

Pros and Cons  Liquid   Corrosive  

   Dirty 

  • Pros:  Steam   Saturated 

  - Very low initial :set

Recommended
up cost
: Limited applicability
  - 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