Sierra InnovaMass 240i Series, Инструкция по эксплуатации, Страница: 19 / 115

19
Connect isolation
valve and test for
leaks
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Purge pipe
Figure 4. Hot Tap Sequence
Flow Meter Insertion
The sensor head must be properly positioned in the pipe. For this reason
, it is important that
insertion length calculations are carefully followed. A sensor probe inserted at the wrong depth in
the pipe will result in inaccurate readings.
Insertion flow meters are applicable to pipes 2-inches and larger. For pipe sizes ten inches and
smaller, the centerline of the meter’s sensing head is located at the pipe’s centerline. For pipe sizes
larger than ten inches, the centerline of the sensing head is located in the pipe’s cross section five
inches from the inner wall of the pipe; i.e., its “wetted” depth from the wall to the centerline of the
sensing head is five inches.
Standard Probe length, S, of the stem is 33.5 inches (850.9 mm).
Compact Probe length is 16.5 inches (419.1 mm).
Use the Correct Insertion Formula
Depending on your flow meter’s process connection, use the applicable insertion length formula
and installation procedure as follows:

Flow meters with a compression type connection (NPT or flanged) follow the instructions
beginning on page 19.

Flow meters with a packing gland type connection (NPT or flanged) follow the instructions
beginning on page 21.
An insertion tool must be used for any installation where a flow meter is
inserted under pressure greater than 50 psig.