WIKA TR10-A - Handbuch (Seite 14)

3345267.12 01/2014 GB/D
14 WIKA operating instructions RTD and TC, intrinsically safe designs (Ex i)
GB
4. Design and function
4.1 Description
These thermometers (resistance thermometers and thermocouples) detect temperatures in
processes. Depending on their design, these thermometers are suitable for low, medium and
high process requirements in hazardous areas.
Insulated measuring point
The model TRxx or model TCxx thermometers consist of a welded tube, a mineral-insulated
sheathed cable or ceramic-insulated thermal wires (in which the temperature sensor is located,
embedded in a ceramic powder), a temperature-resistant sealing compound, cement compound
or a thermal transfer paste.
Alternatives:
The measuring insert or the cable probe can also be provided in a tubular form. In this case, the
sensor is located in a welded tube and embedded in a ceramic powder, heat-conducting paste or
in a sealing compound suitable for this purpose.
The measuring insert for high-temperature thermocouples can also be assembled from thermal
wires insulated with ceramic rods or ceramic beads. The ceramic tube is cemented into a metallic
support tube using a temperature-resistant cement.
Thermocouples, non-insulated (grounded)
For special applications, for example surface temperature measurements, the sensors are in
direct contact with the protective sleeve, or the measuring points of thermocouples are welded to
the bottom (see chapter 7.1.1 “Special conditions of use (X conditions)”).
4. Design and function
Measuring point insulated (ungrounded) Measuring point not insulated (grounded)
Thermocouple Thermocouple Measuring point Measuring point
Sheath Sheath
AI203 powder
MI line
V-Pad welded with
filler
V-Pad version, model TC59-V
Measuring point not insulated