Chapter 1. Installing Pipe Nozzles
4 T5 Flare Gas Transducer Installation Guide
1.2.2 Selecting and Marking the Pipe for Nozzle Locations
1. For optimum performance, you should select a location that has at least 20 pipe diameters of straight,
undisturbed flow upstream and 10 pipe diameters of straight, undisturbed flow downstream from the point of
measurement. Undisturbed flow means avoiding sources of turbulence such as flanges, elbows and tees;
avoiding swirl; and avoiding disturbed flow profiles. Never install the flowmeter downstream of control valves,
especially butterfly valves. If you cannot find a proper location, please consult with Panametrics
Flow Application
engineering.
2. Use a center finder device to locate the center of the pipe. “EYEBALLING” IS NOT ADEQUATE FOR ACCURATE FLOW
MEASUREMENT!
3. Lightly punch two marks approximately 16 in. apart on the top of the pipe, running along the center line. The two
nozzle locations will be located between these two center punch marks.
CAUTION! Correct nozzle alignment is critical to the successful operation of the flowmeter.
Therefore, all marking, positioning and welding operations must be carried out with the
utmost attention to accuracy. Unless otherwise stated, dimensional positioning of the
nozzles must be held to a tolerance of 1/16 in. (±1.6 mm) relative to each other and with
respect to the pipe centerline. The angular tolerance must be held to 1
O
. All hole cutting
in process piping must be performed using hot tapping equipment.
WARNING! Be sure to adhere to all applicable safety regulations.
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