Section 6 | |
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6.1.2 SELECTING THE RIGHT FLOW TUBE
Select the appropriate body material: Consider liquid compatibility, operating temperature, and pres- sure. These must never exceed the rating of the flow tube. Consult installation drawings to determine appropriate fittings for coupling the flow tube into your piping.
Select the appropriate size: Try to match as closely as possible the diameters of the pipe and the flow tube. This will reduce or eliminate the potential for a noticeable pressure drop. In addition, the operating flow range must fall within the indicated specifications.
Flow Tube Pressure and Temperature Ratings
Material | Temperature Range | Max. Pressure |
CPVC | 0°F to 200°F | 150 psig (10.3 bar)* |
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Kynar PVDF | 0°F to 275°F | 150 psig (10.3 bar)* |
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Teflon PFA | 0°F to 250°F | 100 psig (7.0 bar)* |
316 SS (size 1) | 5200 psig (350 bar)* | |
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316 SS (size 2) | 4200 psig (240 bar)* |
*Maximum specifications may be reduced depending on the liquid and operating temperature.
Flow Tube Material, Size & Flow Range Ratings
Material | Size | Flow Range |
CPVC | 1 | 0 to 5 GPM (0 to 20 LPM) |
CPVC | 2 | 0 to 25 GPM (0 to 95 LPM) |
PVDF | 1 | 0 to 5 GPM (0 to 20 LPM) |
PVDF | 2 | 0 to 25 GPM (0 to 95 LPM) |
PFA | 1 | 0 to 5 GPM (0 to 20 LPM) |
PFA | 2 | 0 to 16 GPM (0 to 60 LPM) |
316 SS | 1 | 0 to 10 GPM (0 to 40 LPM) |
316 SS | 2 | 0 to 30 GPM (0 to 115 LPM) |
6.1.3 FLOW TUBE MOUNTING LOCATION
Consider the following guidelines when choosing a Flow Tube mounting location.
a.The flow tube must be mounted horizontally, with its inlet and outlet facing upward. This minimizes the possibility of trapped air bubbles that could interfere with transducer signals.
b.For the best flow profile, locate the flow tube downstream from the center of the longest available straight run. Make sure to locate the inlet upstream relative to the outlet.
c.DO NOT select a location immediately downstream from:
•A throttling valve or other source of cavitation.
•A mixing tank or other device that could aerate the liquid.
•The discharge of a positive displacement pump.
