FLOW METER SELECTION SEMINAR

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FLOW METER SELECTION SEMINAR

• Alan Graff
• RL Stone Co
• IC Sales Manager
• Upstate NY New England

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(No Transcript)
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A Leading Supplier of Flowmeters to HVAC
Industrial Marketplace

• Magmeters
• Vortex Swirl
• Turbine
• Thermal Coriolis Mass
• BTU Meter
• Pitot, Wedge
• Orifice Plates, Venturi
• Positive Displacement
• Rotameter, Variable Area

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Define Application Basic Facts

• Flowing Media (Steam, Water, Air, Gas etc)
• Density - pressure and temperature
• Flow Range, minimum to maximum (turndown needed)
• Accuracy how stated? of range or span
• Repeatability
• Straight run requirements available
• Economic Considerations Initial cost,
  maintenance cost operating costs

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Why are we here?

• There is no 1 meter that will meet every
  application
• Every application needs to be looked at
  individually
• We can make some generalizations !!!!!!

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FLOW MEASUREMENT

• HOW MUCH (TOTAL)

• HOW FAST (RATE)

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Flow Through A Pipe
Real World
Idealized
V
V
Pipe
Velocity Profile
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Flow Profile Correlation
Steam Water Heavy Crude
V

• Velocity profile is a predictable function of
  Reynolds number. Fluids with the same Reynolds
  number will have similar velocity profiles.

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General Flow Terminology

• Reynolds Number (RE) A single dimensionless
  parameter formed as the ratio of inertial to
  viscous forces . Magnitude indicates whether
  flow is laminar or turbulent

CharacteristicDimension(D)
Fluid Density(p)
FluidVelocity(V)
Inertia Forces Viscous Forces

RE
Fluid Viscosity (?)
Usually inside pipe diameter.
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Characterization of Fluid Flow

• Types of Flow
• RE lt 2100
• RE gt3000
• Well documented proven fully developed flow
  profiles

Laminar
Transitional
Turbulent
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Volumetric Flowrate (Q)
V
A
Q
Volume Area x Length Volume Flow Area x
Velocity
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Mass Flowrate (m)
QVA
Qp
Mass Flow m
?AV
V
A
Where m Mass Flow Q Volume Flow ? Fluid
Density
m
Mass Volume x Density
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Mass vs Volume Flowmeters

• Why are we concerned?
• How much does it really matter?
• Flow through a 4 line measured in a Averaging
  Pitot

There is a 6 error just by changing density /
temperature slightlycan you meter cope??
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General Flow Terminology

• Factors affecting flowmeter performance
• Process media
• Liquid
• Gas
• Density (Specific Gravity)
• Viscosity
• Pressure

• Temperature
• Velocity

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Flowmeter Performance

• Accuracy
• Repeatability
• Linearity
• Rangeability

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Types of Accuracy

• Rate
• Full Scale
• Span
• Max DP

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Accuracy
Rate The percent accuracy value is constant and
applied to the actual (or indicated) flowrate
Flowrate 1 rate 100 GPM 1 GPM 50 GPM 0.5
GPM 10 GPM .01 GPM
Example
Full Scale The absolute value of error (as
expressed in engineering units)
Flowrate 1 Full Scale Rate 100 GPM 1
GPM 1 50 GPM 1 GPM 2 10 GPM 1 GPM 10
Example
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Accuracy
Percent Error Versus Flow
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Poor Repeatability Means Poor Accuracy
Good Accuracy Means Good Repeatability
Good Repeatability Does Not Necessarily Mean
Good Accuracy
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Volumetric Flowmeters

• DP
• Turbine
• Vortex / Swirl
• Magnetic
• Target
• Ultrasonic
• Displacement
• Note can be inferred mass with compensating
  transmitter

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Differential Pressure Flowmeters
Flow Measurement Principles
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DP Primary Elements
Flow Nozzle
VariousOrifice Configuration
Flow Tube
Venturi Flowmeter
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DP Primary Elements
Averaging Pitot
Accelabar Combined Pitot Venturi
Wedge Element
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Secondary Flow / DP Transmitter

• Differential Pressure / Flow Transmitter
• Square Root Extraction

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DP Flowmeters
DIFFERENTIAL PRESSURE

• ADVANTAGES
• Use On Liquid, Gas, and Steam
• Suitable for Extreme Temperatures and Pressures
• No Moving Parts
• Low Cost
• DISADVANTAGES
• Limited Rangeability
• Effected By Changes In Density, Pressure, and
  Viscosity
• Maintenance Intensive

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Magnetic Flowmeters
Theory of Operation
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Magmeter Requirements

• Process must be a liquid
• Minimum conductivity
• Meter must be full

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Magnetic Flowmeters
MAGNETIC

• ADVANTAGES
• No Moving Parts
• Very Wide Rangeability
• Ideal For Slurries
• Unobstructed Flow Path
• DISADVANTAGES
• Liquid Must Be Conductive
• Physical Pressure and Temperature Limits

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Magnetic Flowmeters
Advantages Over Other Technologies

• No moving parts
• No pressure drop
• Flowrate independent of viscosity, temperature,
  and density
• Minimum upstream piping requirements
• Electronics interchangeable without regard to
  size
• Measure dirty liquids with solids
• Measure highly corrosive fluids
• Very large turndown
• Linear output

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Vortex Meter

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Vortex Meter
Principle of Operation
Q V x A
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Vortex
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Vortex / Swirlmeter
VORTEX / SWIRLMETER

• ADVANTAGES
• No Moving Parts
• For Liquid, Gas, or Steam
• Uneffected by Pressure, Temperature, or Density
  Changes.
• Wide Rangeability
• DISADVANTAGES
• Span Limitations Due to Viscosity
• Flow Profile Sensitive (Vortex)

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Swirlmeter
Principle of Operation
Preamplifier
Housing
Deswirler
Sensor
Swirler
Backflow
r local radius VA axial velocity of
flow VT angular velocity of flow p static
pressure
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Swirlmeters

• Benefits
• High Accuracy 0.50 of Rate
• No Moving Parts
• Minimal Upstream Piping
• Measures Low Flows
• Versatile
• Electronics can be used for Diagnostics
• Works with Entrained Liquids

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Swirlmeter
Cut-Away View

• Technical Data
• Measures liquids, gases and steam
• Available integral, remote, or flow computer
  electronics
• Accuracy 0.50 rate
• Sizes 0.75" thru 16.0"
• Minimal upstream piping req.
• Flow as low as 1 GPM
• Excellent in light gas applications

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Installation Length
Swirlmeter
Vortex 4
Swirlmeter
Processcontrol valve
5 D
1 D
50 D
5 D
90 elbow
3 D
1 D
25 D
5 D
min. 1.8 D
Reduction
3 D
1 D
15 D
5 D
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Turbine Meter
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Turbine Meter
Principle of Operation
Rotor velocity is proportional to fluid velocity
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Turbine Meter

• High accuracy (.5 of rate)
• High rangeability (up to 501)
• Compact design
• Fast response time
• Broad range of sizes
• Clean water applications only
• NIST Traceable Factory Calibration
• Low cost, Easy to install
• In and out of line, under pressure

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Turbine Meter
Performance Considerations

• Straight pipe run requirements
• Process fluid lubricity
• Reynolds number constraints
• Viscosity
• Density
• Maintenance recalibration

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Turbine Flowmeters
TURBINE

• ADVANTAGES
• High Accuracy
• Suitable for Extreme Temperatures and Pressures
• Can Be Used On Gas or Liquid
• DISADVANTAGES
• Only For Low Viscosities
• Moving Parts
• Sensitive to Flow Profile

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Positive Displacement Flowmeters
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PD Flowmeters
Types

• Helical gear
• Nutating disk
• Oscillating piston
• Oval gear
• Rotary

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Positive Displacement Meter
Typical Principle of Operation
Schematic of a rotary-vane flowmeter
Schematic of a nutating-disk meter
Schematic of a lobed-impeller flowmeter
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PD Flowmeters
Advantages

• Ideal for viscous fluids
• Custody transfer
• Batching
• Minimal straight piping requirements

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Ultrasonic Flowmeters
Types

• Doppler
• Time of flight

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Ultrasonic FlowmetersPrinciple of Operation
DopplerFlowmeter
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Ultrasonic FlowmetersPrinciple of Operation
Transit-TimeFlowmeter
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Ultrasonic Flowmeters
Performance Considerations

• Reynolds number constraints
• Entrained gas or particles for doppler
• Clean liquids for time of flight
• Installed without process shut down
• Straight upstream piping requirements

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Ultrasonic
ULTRASONIC

• ADVANTAGES
• No Moving Parts
• Unobstructed Flow Passage
• Wide Rangeability
• DISADVANTAGES
• For Liquids Only (limited gas)
• Flow Profile Dependent
• Errors Due To Deposits

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Mass Flowmeter

• Direct Measurement
• Thermal Dispersion
• Coriolis

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Coriolis Mass Flowmeter
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Coriolis

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Coriolis
CORIOLIS

• ADVANTAGES
• Direct Mass Measurement
• High Accuracy
• Additional Density Measurement
• Uneffected By Flow Profile
• DISADVANTAGES
• High Purchase Price
• High Installation Cost
• Size Limitations
• Vibration Sensitive

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Thermal Dispersion
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Thermal Dispersion Mass Flowmeter

• Gas application only
• Relatively inexpensive
• Easy to install and remove under pressure
• Accuracy 0.5
• Turndown, 1001
• Capable of monitoring extremely low flows
• True mass flow meter (compensates for
  temperature/pressure)

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Piping Considerations

• Always need a full pipe
• Proper up / down diameter

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BTU Monitoring
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Summary Each Application is Different

• Flowing Media (eg Steam, Water, Air, Gas etc)
• Density - pressure and temperature
• Flow Range, minimum to maximum (turndown needed)
• Accuracy how stated? of range or span
• Repeatability
• Straight run requirements available
• Maintenance and reliability

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General HVAC Recommendations
Steam Accelabar or Swirl Chilled or Hot Water
Hot Tap Insert Turbine Natural Gas or Air
Thermal Dispersion Fuel Oil Coriolis or Wedge
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The End