Transcript FLOW METER SELECTION SEMINAR

FLOW METER SELECTION
SEMINAR
Alan Graff
RL Stone Co
I&C Sales Manager
Upstate NY & New England
RL Stone Co. New England
Corporate Office: 115 Ainsley Drive, Syracuse, NY 13210 • Tel: 888-404-8882 • Fax: 315-479-5402 www.rl-stone.com
Process/HVAC Products and Solutions
Armstrong Steam and Condensate Group: Traps, Liquid Drainers, Steam
Distribution & Condensate Return Manifolds, Air Vents, Strainers, Wireless
Trap Monitors, Spargers, Separators
Armstrong Humidification Group (Vermont only): Direct Steam, Ionic Bed
Electric, Gas-Fired, Steam to-Steam, Evaporative Cooling Fogging, Unfired Steam Generators
Armstrong Condensate Management Group: Mechanical & Electrical
Condensate Pumps and Packages, Flash Tanks, Condensate Coolers
Armstrong Heat Transfer Group: Unit Heaters, Door Heaters and Make-Up
Air Heaters, Heavy-Duty Steam and Hot Water Coils, Replacement Coils,
DuraMix VIFB Coils, Fumigation Heat Treat Systems
Armstrong Hot Water Group: Instantaneous Hot Water Heaters, Direct
Fired Gas High Efficiency Hot Water Heaters, Thermostatic Mixing Valves, “The
Brain” & MEGAMIX Digital Electronic Mixing Center, Steam & Hot Water Hose
and Mixing Valve Stations
Armstrong Pressure Temperature Control Group: PRV’s, Pneumatic and
Electric Industrial Control Valves, Temperature Regulators, Radiator Control
Valves
Armstrong Service Group: Steam System Optimization, Contracting:
Installation Construction, Engineering Audits and Steam Surveys, Heat Treat
Audits
Cataract Steel
Compressed Air, Gas & Heat Transfer Products, Industrial Heat
Exchangers, Pressure Vessels, Air Receivers
New and Replacement Steam, Water and DX Coils, Remote Condensers,
Fluid Coolers, Evaporative Coolers
Diversified Heat
Transfer
Heat Transfer Equipment, Shell and Tube Heat Exchangers, Plate and
Frame Heat Exchangers, Steam and Hot Water Generators
Refrigerant Leak Detection Monitoring Systems
Thermacor
Process
Pre-Insulated Above and Below Ground Piping Systems,
Containment Piping, High Temperature Polyisocyanurate
Foam, Pressure Testable Joints, ERM Leak Detection
TMI, Inc
Strip Doors, Air Doors, Screens and Curtains, Modular Enclosures,
Clear and Colored Flexible PVC Film, Noise Control Products
Flow Sensors & Instrumentation, Accelabar Zero Straight Run
Flow Meter, Utility Flow Metering Systems
Gauges: Pressure, Vacuum, Digital and Analog Indicators, Mini and
Industrial Diaphragm Seals, Pressure Transducers, AccessoriesPressure Snubbers, Gauge Cocks, Needle Valves, Siphons, Pete’s Plugs,
Bimetal Thermometers and Temperature Transmitters
R. L. Stone Services
Design Build, Installation, On-Site Seminars and Training, Energy
Audits, Steam Trap Surveys, Control Panels, SCADA System
A Leading Supplier of Flowmeters
to HVAC & Industrial Marketplace
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Magmeters
Vortex & Swirl
Turbine
Thermal & Coriolis Mass
BTU Meter
Pitot, Wedge
Orifice Plates, Venturi
Positive Displacement
Rotameter, Variable Area
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
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 !!!!!!
FLOW MEASUREMENT
•HOW MUCH (TOTAL)
• HOW FAST (RATE)
Flow Through A Pipe
Idealized
V
Real World
V
Pipe
Velocity Profile
Flow Profile Correlation
V
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Steam
Water
Heavy Crude
Velocity profile is a predictable function of Reynolds
number. Fluids with the same Reynolds number will have
similar velocity profiles.
General Flow Terminology
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Reynolds Number (RE)– A single dimensionless
parameter formed as the ratio of inertial to
viscous forces . Magnitude indicates whether
flow is laminar or turbulent
RE=
Inertia Forces
Viscous Forces
=
Fluid
Density
(p)
Fluid
Velocity
(V)
Characteristic
Dimension*
(D)
Fluid Viscosity ()
* Usually inside pipe diameter.
Characterization of Fluid Flow
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Types of Flow
RE < 2100
Laminar
Transitional
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RE >3000
Turbulent ***
*** Well documented & proven fully
developed flow profiles
Volumetric Flowrate (Q)
V
A
Q
Volume = Area x Length
Volume Flow = Area x Velocity
Mass Flowrate (m)
Q=VA
Mass Flow m =
Qp
= AV
V
A
m
Where
m
Q

= Mass Flow
= Volume Flow
= Fluid Density
Mass = Volume x Density
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
1000 cfm
Pressure
5 psi
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??
General Flow Terminology
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Factors affecting flowmeter performance
 Process
– Liquid
– Gas
 Density
media
 Temperature
 Velocity
(Specific Gravity)
 Viscosity
 Pressure
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
±1 GPM
Example: 100 GPM
50 GPM
±0.5 GPM
10 GPM
±.01 GPM
% Full Scale The absolute value of error (as expressed in
engineering units)
Flowrate
Example: 100 GPM
50 GPM
10 GPM
±1% Full Scale
±1 GPM
±1 GPM
±1 GPM
% Rate
±1%
±2%
±10%
Accuracy
Percent Error Versus Flow
Poor Repeatability Means
Poor Accuracy
Good Accuracy Means
Good Repeatability
Good Repeatability Does Not
Necessarily Mean Good Accuracy
Volumetric Flowmeters
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DP
Turbine
Vortex / Swirl
Magnetic
Target
Ultrasonic
Displacement
• Note: can be inferred mass with compensating transmitter
Differential Pressure Flowmeters
Flow Measurement Principles
Q=K
ORIFICE PLATE
(or FLOW TUBE)
VENA
CONTRACTA
Direction of Flow
h
MANOMETER
(or DP TRANSMITTER)
P
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DP Primary Elements
Various
Orifice
Configuration
Flow
Tube
Flow
Nozzle
Venturi
Flowmeter
DP Primary Elements
Averaging Pitot
Accelabar – Combined
Pitot & Venturi
Wedge Element
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
Magnetic Flowmeters
Theory of Operation
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
Magnetic Flowmeters
Advantages Over Other Technologies
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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
Vortex Meter
Vortex Meter
Principle of Operation
Q=VxA
Vortex
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)
Swirlmeter
Principle of Operation
Preamplifier
Housing
Swirler
Sensor Deswirler
Backflow
r
VA
VT
p
=
=
=
=
local radius
axial velocity of flow
angular velocity of flow
static pressure
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
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
Installation Length
Swirlmeter
Swirlmeter
Vortex 4
Process
control valve
5D
1D
3D
1D
50 D
5D
25 D
5D
15 D
5D
90° elbow
min. 1.8 D
Reduction
3D
1D
Turbine Meter
Turbine Meter
Principle of Operation
Rotor velocity is proportional to fluid velocity
Turbine Meter
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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
Turbine Meter
Performance Considerations
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Straight pipe run requirements
Process fluid lubricity
Reynolds number constraints
 Viscosity
 Density
Maintenance & recalibration
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
Positive Displacement Flowmeters
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
nutating-disk meter
Schematic of a
rotary-vane flowmeter
Schematic of a
lobed-impeller flowmeter
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 Flowmeters
Principle of Operation
Doppler
Flowmeter
Ultrasonic Flowmeters
Principle of Operation
Transit-Time
Flowmeter
Ultrasonic Flowmeters
Performance Considerations
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Reynolds number constraints
Entrained gas or particles for doppler
Clean liquids for time of flight
Installed without process shut down
Straight upstream piping
requirements
Ultrasonic
ULTRASONIC
ADVANTAGES
• No Moving Parts
• Unobstructed Flow Passage
• Wide Rangeability
V
DISADVANTAGES
• For Liquids Only (limited gas)
• Flow Profile Dependent
• Errors Due To Deposits
Mass Flowmeter
Direct Measurement
• Thermal Dispersion
• Coriolis
Coriolis Mass Flowmeter
Coriolis
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
Thermal Dispersion
Thermal Dispersion Mass Flowmeter
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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)
Piping Considerations
• Always need a full pipe
• Proper up / down diameter
BTU Monitoring
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
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