Panametrics C-ET, Installation Manual

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4 Model C-ET Installation Guide
1.3.1 Choosing an Installation Location
1. Locate the transducer measurement point at least 3 ft (1 m) from any butt welds or flanges, ideally in the center
of a 20 diameters of straight run of pipe. Keep appropriate clearance on either side of the pipe for easy
transducer installation:
•
6 in. (15 cm) if you are not using a junction box, or
•
9 in. (23 cm) if you are using a junction box.
Note: To guarantee the specified accuracy of the flowmeter there is no substitute for straight run and
fully-developed flow profile. However, if straight run is not available, the transducer location should be in a
position such that the acoustic signal travels through the full distribution of the under-developed flow profile
for best repeatability.
2. Choose a location that has at least 10 pipe diameters of straight, undisturbed flow upstream and 5 pipe
diameters downstream from the measurement point. Providing undisturbed flow means avoiding sources of
turbulence such as flanges, elbows and tees; avoiding swirl; and avoiding disturbed flow profiles. Never install the
flowmeter directly downstream of control valves, especially butterfly valves. If you cannot find an ideal location,
use a downstream location of straight run in excess of 5 pipe diameters.
3. Place the transducers as close as possible to the horizontal plane. Locate the transducers on opposite sides of
the pipe 180
o
apart, ideally at the 3 and 9 o’clock positions. Do not place transducers on the top or bottom of the
pipe.
Figure 3: Transducer Locations
4. The following is a guide for the recommended wall thickness in which to install the C-ET transducers. The C-ET
transducer cannot be installed on wall thicknesses between 0.27 in (6.86 mm) and 0.33 in (8.38 mm). On page 5
and page 6 are two charts showing typical pipe sizes.
Transducer
Pipe
Signal Path
End View