WIKA TR25 Betriebsanleitung Seite 20

7. Information on mounting and operation in hazardous areas
7.3 Temperature carry-over from the process
A heat backflow from the process that exceeds the operating temperature of the transmitter
(digital display) or housing is not permissible and must be prevented by installing suitable
heat insulation or a neck tube of suitable length.
EN
Increasing the separation of the connection components and hot surfaces
The neck distance (N) is defined as the distance between the lower edge of the connection
head (or the housing) to the heat-emitting surface. The temperature to be expected at the
lower edge of the connection head or housing is, at most, 80 °C. The conditions for built-in
transmitters or displays must be observed. If required, the neck length must be increased
accordingly.
To help select the minimum neck length, the following standard values have been
determined.
Maximum temperature of the
medium
100 °C
135 °C
200 °C
> 200 °C ≤ 450 °C
WARNING!
For reasons of work safety and saving of resources, hot surfaces should be
protected against accidental touch and energy loss by means of insulation.
20
Recommendation for
dimension N
-
20 mm
50 mm
100 mm
WIKA operating instructions model TR25 (Ex i)
Recommendation for
dimension X
-
20 mm
50 mm
100 mm