WIKA 70-8xx - Manual (Page 8)

GB
8
11472988.02 04/2013 GB/D/F/E
WIKA operating instructions expansion thermometer, model 70
3. Specifications
Specifications with micro switch without micro switch
Nominal size in mm 100 63, 100, 160
Measuring principle Bourdon tube system
Filling medium Xylol, silicone oil or syltherm Xylol or silicone oil
Capillary entry lower mount or back mount
Case Stainless steel
Indication accuracy Class 2
Scale range -100 ... +400 °C
Measuring line Ø 2 mm, stainless steel 1.4571
Length of the measuring line Max. 10 m
Contact max. 2 micro switches (adjustable/fixed)
Load data 5 A, AC 48 V
The instruments do not provide for incorporated overcurrent
protectors. In order to prevent the contacts from welding through
overload, suitable protection systems must be implemented by
the operator.
Setting range from 10 % to 90 % of the full scale value
Fixed, factory set to customer specification
Standard switch differential < 2 % of measuring range
Electrical connection via cable terminal box
Ingress protection
per EN 60529 / IEC 529
IP 44 IP 65
For further specifications, see WIKA data sheet TV 28.01 or TM 81.01 and the order
documentation.
4. Design and function
4.1 Description
The liquid-filled, closed measuring system consists of a temperature sensor, a capillary
and a Bourdon tube. The volume change as a consequence of the heat applied to the
temperature sensor, and thus the pressure change in the closed system, is transmitted
through the capillary to the Bourdon tube and then indicated on the dial by the angular
deflection of the pointer shaft.
Temperature measuring instruments with micro switch (temperature controllers)
The switching disc (cam disc) connected to the pointer shaft actuates the switching
operation on the micro switch when the switch point is reached.
3. Specifications / 4. Design and function