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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 Heat Transfer Equipment, Shell and Tube Heat Exchangers, Plate and Transfer Frame Heat Exchangers, Steam and Hot Water Generators
Refrigerant Leak Detection Monitoring Systems
Thermacor Pre-Insulated Above and Below Ground Piping Systems, Process Containment Piping, High Temperature Polyisocyanurate
Foam, Pressure Testable J oints, 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, Accessories-Pressure 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 A Leading Supplier of Flowmeters to HVAC & Industrial MarketplaceHVAC & Industrial Marketplace
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 !!!!!!
•HOW MUCH (TOTAL)
• HOW FAST (RATE)
FLOW MEASUREMENT
Flow Through A PipeFlow Through A Pipe
Real WorldIdealized
Pipe Velocity Profile
VV
Flow Profile CorrelationFlow Profile Correlation
Velocity profile is a predictable function of Reynolds number. Fluids with the same Reynolds number will have similar velocity profiles.
SteamWaterHeavy Crude
V
General Flow TerminologyGeneral 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 Viscosity ()RE=
FluidDensity
(p)
FluidVelocity
(V)Inertia Forces
Viscous Forces
* Usually inside pipe diameter.
Characterization of Fluid FlowCharacterization of Fluid Flow
Types of Flow RE < 2100
RE >3000
*** Well documented & proven fully developed flow profiles
Transitional
Turbulent ***
Laminar
Volumetric Flowrate (Q)Volumetric Flowrate (Q)
Volume = Area x LengthVolume Flow = Area x
Velocity
VA
Q
Mass Flowrate (m)Mass Flowrate (m)
Where m = Mass FlowQ = Volume Flow = Fluid Density
= AV
Mass = Volume x Density
Mass Flow m = Qp
VA
m
Q=VA
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 TerminologyGeneral Flow Terminology
Factors affecting flowmeter performance Process media
– Liquid– Gas
Density (Specific Gravity) Viscosity Pressure
Temperature Velocity
Flowmeter PerformanceFlowmeter Performance
Accuracy Repeatability Linearity Rangeability
Types of AccuracyTypes of Accuracy
% Rate % Full
Scale % Span % Max DP
AccuracyAccuracy
% Rate The percent accuracy value is constant and applied to the actual (or indicated) flowrate
Example:
Flowrate ±1% rate100 GPM ±1 GPM50 GPM ±0.5 GPM10 GPM ±.01 GPM
% Full Scale The absolute value of error (as expressed in engineering units) Flowrate ±1% Full Scale %
Rate100 GPM ±1 GPM ±1%50 GPM ±1 GPM ±2%10 GPM ±1 GPM ±10%
Example:
AccuracyAccuracy
Percent Error Versus Flow
Poor Repeatability Means Poor Accuracy
Good Accuracy Means Good Repeatability
Good Repeatability Does Not Necessarily Mean Good Accuracy
Volumetric Flowmeters
• DP• Turbine• Vortex / Swirl• Magnetic• Target• Ultrasonic• Displacement
• Note: can be inferred mass with compensating transmitter
Differential Pressure FlowmetersDifferential Pressure Flowmeters
Flow Measurement Principles
PQ = K
ORIFICE PLATE(or FLOW TUBE) VENA
CONTRACTA
MANOMETER(or DP TRANSMITTER)h
Direction of Flow
DP Primary ElementsDP Primary Elements
VariousOrificeConfiguration
FlowNozzle
VenturiFlowmeter
FlowTube
DP Primary ElementsDP Primary Elements
Averaging Pitot
Accelabar – Combined Pitot & Venturi
Wedge Element
DP FlowmetersDP Flowmeters
DIFFERENTIAL PRESSUREADVANTAGES
• 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 FlowmetersMagnetic Flowmeters
Theory of Operation
Magmeter RequirementsMagmeter Requirements
Process must be a liquid
Minimum conductivity
Meter must be full
Magnetic FlowmetersMagnetic Flowmeters
MAGNETICADVANTAGES
• No Moving Parts
• Very Wide Rangeability
• Ideal For Slurries
• Unobstructed Flow Path
DISADVANTAGES
• Liquid Must Be Conductive
• Physical Pressure and Temperature Limits
Magnetic FlowmetersMagnetic Flowmeters
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
Advantages Over Other Technologies
Vortex Meter Vortex Meter
Vortex MeterVortex Meter
Principle of Operation
Q = V x A
VortexVortex
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)
VORTEX / SWIRLMETER
SwirlmeterSwirlmeter
Principle of OperationPreamplifier
Swirler Sensor Deswirler
r = local radiusVA = axial velocity of flowVT = angular velocity of flowp = static pressure
Backflow
Housing
SwirlmetersSwirlmeters
BenefitsBenefits
• 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
SwirlmeterSwirlmeter
Cut-Away ViewTechnical 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 LengthInstallation Length
Swirlmeter
15 D 5 D
25 D 5 D
50 D 5 D
Vortex 4Swirlmeter
90° elbow
Processcontrol valve
Reduction
3 D 1 D
3 D 1 D
5 D 1 D
min. 1.8 D
Turbine MeterTurbine Meter
Turbine MeterTurbine Meter
Principle of Operation
Rotor velocity is proportional to fluid velocity
Turbine MeterTurbine Meter
High accuracy (.5% of rate) High rangeability (up to 50:1) Compact design Fast response time Broad range of sizes Clean water applications onlyClean water applications only NIST Traceable Factory CalibrationNIST Traceable Factory Calibration Low cost, Easy to installLow cost, Easy to install In and out of line, under pressureIn and out of line, under pressure
Turbine MeterTurbine Meter
Straight pipe run requirements Process fluid lubricity Reynolds number constraints
ViscosityDensity
Maintenance & recalibration
Performance Considerations
Turbine FlowmetersTurbine Flowmeters
TURBINEADVANTAGES
• 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 FlowmetersPositive Displacement Flowmeters
PD FlowmetersPD Flowmeters
Helical gear Nutating disk Oscillating
piston Oval gear Rotary
Types
Positive Displacement MeterPositive 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 FlowmetersPD Flowmeters
Ideal for viscous fluids Custody transfer Batching Minimal straight piping
requirements
Advantages
Ultrasonic FlowmetersUltrasonic Flowmeters
Doppler Time of
flight
Types
DopplerFlowmeter
Ultrasonic FlowmetersUltrasonic FlowmetersPrinciple of OperationPrinciple of Operation
Ultrasonic FlowmetersUltrasonic FlowmetersPrinciple of OperationPrinciple of Operation
Transit-TimeFlowmeter
Ultrasonic FlowmetersUltrasonic Flowmeters
Reynolds number constraints Entrained gas or particles for
doppler Clean liquids for time of flight Installed without process shut
down Straight upstream piping
requirements
Performance Considerations
UltrasonicUltrasonic
ULTRASONICADVANTAGES
• No Moving Parts
• Unobstructed Flow Passage
• Wide Rangeability
DISADVANTAGES
• For Liquids Only (limited gas)
• Flow Profile Dependent
• Errors Due To Deposits
V
Mass Flowmeter
Direct Measurement
• Thermal Dispersion• Coriolis
Coriolis Mass FlowmeterCoriolis Mass Flowmeter
CoriolisCoriolis
CoriolisCoriolis
CORIOLISADVANTAGES
• 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
• 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 DifferentSummary – 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