1. FLOW METER SELECTION SEMINAR
Alan Graff
RL Stone Co
I&C Sales Manager
Upstate NY & New England

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
Idealized
Real World 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. Characteristic Dimension* (D)
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
Fluid
Density (p)
Fluid Velocity (V)
Characteristic Dimension* (D)
Inertia Forces
Viscous Forces
RE= =
Fluid Viscosity ()
* Usually inside pipe diameter.

10. Types of Flow Characterization of Fluid Flow RE < 2100 RE >3000
*** Well documented & proven fully developed flow profiles
Laminar
Transitional
Turbulent ***

11. Volume Flow = Area x Velocity
Volumetric Flowrate (Q) V A Q
Volume = Area x Length
Volume Flow = Area x Velocity

12. Mass Flowrate (m) V A m Q=VA Mass Flow m = Qp = AV
Where m = Mass Flow
Q = Volume Flow
 = Fluid Density
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
Flow Rate
1000 cfm
Pressure
5 psi
Temperature
100 F
70 F
DP in WC
12.181
11.532
There is a 6% error just by changing density / temperature slightly…can you meter cope??

14. Factors affecting flowmeter performance
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 FlowmetersDP
Turbine
Vortex / Swirl
Magnetic
Target
Ultrasonic
Displacement
Note: can be inferred mass with compensating transmitter

21. Differential Pressure Flowmeters
Flow Measurement Principles P 
Q = K
ORIFICE PLATE (or FLOW TUBE)
VENA CONTRACTA
MANOMETER (or DP TRANSMITTER) h
Direction of Flow

22. DP Primary Elements Flow Various Orifice Nozzle Configuration Flow
Tube
Venturi
Flowmeter

23. DP Primary Elements Averaging Pitot
Accelabar – Combined Pitot & Venturi
Wedge Element

24. Differential Pressure / Flow Transmitter Square Root Extraction
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. Process must be a liquid Minimum conductivity Meter must be full
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
Backflow
r = local radius
VA = axial velocity of flow
VT = angular velocity of flow
p = static pressure

35. Benefits Swirlmeters 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 Swirlmeter Vortex 4
Process control 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 50:1)
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. Performance Considerations
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. Types Helical gear Nutating disk Oscillating piston Oval gear Rotary
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. Ideal for viscous fluids Custody transfer Batching
PD Flowmeters
Advantages
Ideal for viscous fluids
Custody transfer
Batching
Minimal straight piping requirements

47. Ultrasonic Flowmeters
Types
Doppler
Time of flight

48. Ultrasonic Flowmeters Principle of Operation
Doppler Flowmeter

49. Transit-Time Flowmeter
Ultrasonic Flowmeters Principle of Operation
Transit-Time Flowmeter

50. Performance Considerations
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

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, 100:1
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