Instructions for Use
– SCHMIDT
®
Flow Sensor SS 20.700
Page 7
For measurements in media with overpressure, appropriate
safety measures must be taken to prevent unintended discard-
ing of the sensor.
The pressure-tight mounting, the fastening of the screw pipe
connection and the discarding protection must be checked be-
fore pressure is applied. These tightness checks must be re-
peated at reasonable intervals.
The components of the pressure protection kit (bolt, chain and
bracket) have to be checked regularly for integrity.
Thermal boundary conditions
In the case of medium temperatures that
don’t correspond to the permis-
sible operating temperature of the electronics, cross-talk of the tempera-
ture into the electronics housing must be prevented by a thermal decou-
pling section of the sensor tube having a free-standing length of at least
50 mm (see Figure 3-1) or by means of other suitable measures.
Figure 3-1
The permissible operating temperature range of the electronics
must not be exceeded by crosstalk of the medium temperature on
the sensor housing.
Flow characteristics
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 laminar
4
state,
i.e. quiet and low in turbulence. The corresponding measures depend on
the system properties (pipe, chamber, etc.) which are described in the fol-
lowing subchapters for different mounting variants.
Correct measurements require a (laminar) flow, low in turbulence.
4
The term “laminar” means here an air flow, low in turbulence (not according to its physical
definition saying that the Reynolds number is < 2300).
> 50 mm
2
