Instructions for Use
– SCHMIDT
®
Flow sensor SS 20.260
Page 5
The sensor should preferably be installed in horizontally positioned pipes.
A sensor mounted in opposite direction of the flow direction leads to wrong
measuring values (too high).
Due to system characteristics the lower measuring range limit of
the sensor is 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
Always position the sensor head, if possible, in the middle of the
pipe or shaft.
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 state and
low in turbulence 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 disturb-
ances (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