Schmidt SS 20.501, Instructions For Use Manual

Page: 21 / 48

Seite 21
Installation information
Determination of the place of installation
To reach the accuracy specified in the data sheets, the sensor has to be posi-
tioned in a straight conduit and at a place with undisturbed flow profile. An undis-
turbed flow profile can be achieved if a sufficiently long distance in front of the
sensor (run-in distance) and behind the sensor (run-out distance) is held abso-
lutely straight and without disturbances (such as edges, seams, bends, etc.).
The design of the run-out distance is also important, since disturbances act not
only
in the direction of the air flow but also lead to turbulence opposite to the
flow direction.
L = Total length of the measuring distance,
L1 = length of the run-in distance,
L2 = length of the run-out distance,
D = diameter of the measuring distance
The following table shows the necessary straight conduit lengths as a function of
each disturbance.