4.0 Site considerations
4.1 Local mounting
The flow transmitter accuracy is affected by the flowcell location in the process piping and on the orientation of the
transducers. Thus, in addition to accessibility for maintenance, adhere to the following installation guidelines:
• Locate the flowcell so that there are at least 10 pipe diameters of straight, undisturbed flow upstream and 5 pipe diameters
of straight, undisturbed flow downstream from the measurement point (see Figure 2 below). Undisturbed flow means
avoiding sources of turbulence in the fluid (e.g., valves, flanges, expansions, elbows, etc.), avoiding swirl, and avoiding
cavitation.
Flow Direction
10D
5D
Figure 2: Minimum straight run pipe requirements
• Locate the transducers on a common axial plane along the pipe. Also, locate them on the side of the pipe instead of on the
top or the bottom, because the top of the pipe tends to accumulate gas and the bottom tends to accumulate sediment.
Either condition will cause unwanted attenuation of the ultrasonic signals. There is no similar restriction with vertical pipes,
as long as the fluid flow is upward to prevent free falling of the fluid or a less than full pipe (see
Figure 3
below).
BAD
Vertical
GOOD
Flow
Dir
ec
tion
Flow
Dir
ec
tion
Flowcell
Flow Direction
GOOD
BAD
Horizontal
Flowcell
Figure 3: Good and bad flowcell/transducer orientations
CAUTION!
Do not place thermal insulation on or around the transducers, the junction boxes, or the meter electronics.
The transducer and junction box act as a heat sink that protects the transducer from high and low
temperatures.
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