Instructions for Use SS 20.260
Page 5
The lower measuring range limit is according to the system
requirements 0.2 m/s.
At lower flow velocities (< 2 m/s) the measured medium tem-
perature is too high.
The center of the chamber head is the actual measuring point of the flow
measurement and must be placed in the flow as advantageous as possi-
ble, for example in the middle of a pipe (see Figure 1). Therefore this
point is also used for specification of probe length L (see Figure 2).
Figure 1
Positioning in a pipe
In closed systems the sensor head must be located in the
cen-
ter of the pipe
.
Installation with low disturbance
Local turbulences of the medium can cause distortion of measurement
results. Therefore, appropriate mounting conditions must be guaranteed
to ensure that the gas flow is supplied to the sensor in a quiet and low in
turbulence state in order to maintain the accuracy specified (see chapter
).
Correct measurements require quiet flow, as low-turbulence as
possible.
An undisturbed flow profile can be achieved if a sufficiently long distance
in front of (run-in distance) and behind (run-out distance) the sensor in-
stallation site (see Figure 2) is held absolutely straight and without dis-
turbances (such as edges, seams, bends etc.). It is also necessary to
pay attention to the design of the run-out distance because disturbances
also generate turbulences
against
the flow direction.
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Flow
Direction of measurement