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FLOW METER SELECTION SEMINAR

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Title: FLOW METER SELECTION SEMINAR


1
FLOW METER SELECTION SEMINAR
  • Alan Graff
  • RL Stone Co
  • IC Sales Manager
  • Upstate NY New England

2
(No Transcript)
3
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

4
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

5
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 !!!!!!

6
FLOW MEASUREMENT
  • HOW MUCH (TOTAL)
  • HOW FAST (RATE)

7
Flow Through A Pipe
Real World
Idealized
V
V
Pipe
Velocity Profile
8
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.

9
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.
10
Characterization of Fluid Flow
  • Types of Flow
  • RE lt 2100
  • RE gt3000
  • Well documented proven fully developed flow
    profiles

Laminar
Transitional
Turbulent
11
Volumetric Flowrate (Q)
V
A
Q
Volume Area x Length Volume Flow Area x
Velocity
12
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
13
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??
14
General Flow Terminology
  • Factors affecting flowmeter performance
  • Process media
  • Liquid
  • Gas
  • Density (Specific Gravity)
  • Viscosity
  • Pressure
  • Temperature
  • Velocity

15
Flowmeter Performance
  • Accuracy
  • Repeatability
  • Linearity
  • Rangeability

16
Types of Accuracy
  • Rate
  • Full Scale
  • Span
  • Max DP

17
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
18
Accuracy
Percent Error Versus Flow
19
Poor Repeatability Means Poor Accuracy
Good Accuracy Means Good Repeatability
Good Repeatability Does Not Necessarily Mean
Good Accuracy
20
Volumetric Flowmeters
  • DP
  • Turbine
  • Vortex / Swirl
  • Magnetic
  • Target
  • Ultrasonic
  • Displacement
  • Note can be inferred mass with compensating
    transmitter

21
Differential Pressure Flowmeters
Flow Measurement Principles
22
DP Primary Elements
Flow Nozzle
VariousOrifice Configuration
Flow Tube
Venturi Flowmeter
23
DP Primary Elements
Averaging Pitot
Accelabar Combined Pitot Venturi
Wedge Element
24
Secondary Flow / DP Transmitter
  • Differential Pressure / Flow Transmitter
  • Square Root Extraction

25
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

26
Magnetic Flowmeters
Theory of Operation
27
Magmeter Requirements
  • Process must be a liquid
  • Minimum conductivity
  • Meter must be full

28
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

29
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

30
Vortex Meter

31
Vortex Meter
Principle of Operation
Q V x A
32
Vortex
33
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)

34
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
35
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

36
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

37
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
38
Turbine Meter
39
Turbine Meter
Principle of Operation
Rotor velocity is proportional to fluid velocity
40
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

41
Turbine Meter
Performance Considerations
  • Straight pipe run requirements
  • Process fluid lubricity
  • Reynolds number constraints
  • Viscosity
  • Density
  • Maintenance recalibration

42
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

43
Positive Displacement Flowmeters
44
PD Flowmeters
Types
  • Helical gear
  • Nutating disk
  • Oscillating piston
  • Oval gear
  • Rotary

45
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
46
PD Flowmeters
Advantages
  • Ideal for viscous fluids
  • Custody transfer
  • Batching
  • Minimal straight piping requirements

47
Ultrasonic Flowmeters
Types
  • Doppler
  • Time of flight

48
Ultrasonic FlowmetersPrinciple of Operation
DopplerFlowmeter
49
Ultrasonic FlowmetersPrinciple of Operation
Transit-TimeFlowmeter
50
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

51
Ultrasonic
ULTRASONIC
  • ADVANTAGES
  • No Moving Parts
  • Unobstructed Flow Passage
  • Wide Rangeability
  • DISADVANTAGES
  • For Liquids Only (limited gas)
  • Flow Profile Dependent
  • Errors Due To Deposits

52
Mass Flowmeter
  • Direct Measurement
  • Thermal Dispersion
  • Coriolis

53
Coriolis Mass Flowmeter
54
(No Transcript)
55
Coriolis

56
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

57
Thermal Dispersion
58
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)

59
Piping Considerations
  • Always need a full pipe
  • Proper up / down diameter

60
BTU Monitoring
61
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

62
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
63
The End
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