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

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

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 Real World V V Pipe Velocity Profile

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.

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.

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

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

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

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??

Factors affecting flowmeter performance General Flow Terminology Factors affecting flowmeter performance Process media Liquid Gas Density (Specific Gravity) Viscosity Pressure Temperature Velocity

Flowmeter Performance Accuracy Repeatability Linearity Rangeability

Types of Accuracy % Rate % Full Scale % Span % Max DP

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:

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

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

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

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

Differential Pressure / Flow Transmitter Square Root Extraction Secondary Flow / DP Transmitter Differential Pressure / Flow Transmitter Square Root Extraction

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

Process must be a liquid Minimum conductivity Meter must be full Magmeter Requirements Process must be a liquid Minimum conductivity Meter must be full

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 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 = V x A

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 Deswirler Sensor Backflow r = local radius VA = axial velocity of flow VT = angular velocity of flow p = static pressure

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

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 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

Turbine Meter

Turbine Meter Principle of Operation Rotor velocity is proportional to fluid velocity

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

Performance Considerations Turbine Meter Performance Considerations 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

Types Helical gear Nutating disk Oscillating piston Oval gear Rotary PD Flowmeters Types Helical gear Nutating disk Oscillating piston Oval gear Rotary

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

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

Ultrasonic Flowmeters Types Doppler Time of flight

Ultrasonic Flowmeters Principle of Operation Doppler Flowmeter

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

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

Ultrasonic ULTRASONIC ADVANTAGES No Moving Parts Unobstructed Flow Passage Wide Rangeability 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 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

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