WIKA 73 - Manual (Page 13)

GB
11591367.02 05/2012 GB/D/F/E
WIKA operating instructions models 73, 74 (ATEX) 13
■ If possible, the entire length of the stem should be exposed to the
temperature being measured. However, at least the length of the
active part that corresponds to the length of the gas expansion
vessel (active length).
■ In pipelines or other measuring points, the temperature probe must
be angled as far towards the flow as possible.
■ Errors in thermal conduction occur if the area where the
temperature is to be measured is so small, that the mass of the
temperature probe acts as thermal capacity. Errors in thermal
conduction may also occur if the immersion depth is insufficient, if
the mounting fittings are connected to a good thermal conductor
(metal plate or similar) and there is a considerable difference
in temperature between the measuring and mounting element
temperatures.
■ Mount the indicator case free from vibration. If necessary, it is
possible to isolate the instrument from the mounting point by
installing a flexible connection line between the measuring point
and the thermometer and mounting the instrument on a suitable
bracket.
If this is not possible, the following limit values must not be exceeded:
Dry gauges: Frequency range < 150 Hz
Acceleration < 0.7 g (7 m/s 2 )
Liquid-filled gauges: Frequency range < 150 Hz
Acceleration < 2 g (20 m/s 2 )
6. Commissioning, operation
After mounting, set the compensating valve (if
available) from CLOSE to OPEN.