WIKA 632.51 Mode D'emploi page 12

2. Safety
Explosive dust/air atmospheres
For dusts, the procedure specified in ISO/IEC 80079-20-2 for determining the
ignition temperature has to be applied. The ignition temperature is determined
separately for dust clouds and dust layers, respectively. For dust layers, the igniti-
on temperature depends on the dust layer thickness per IEC/EN 60079-14.
Ignition temperature
of dust
Dust cloud: T
cloud
FR
Dust layer: T
layer
The permissible maximum medium temperature must not exceed the lowest
determined value, even in case of a malfunction.
Explosive atmosphere consisting of hybrid mixtures
The instruments must not be used in areas in which an atmosphere consisting of
explosive hybrid mixtures (dusts mixed with gases) can occur.
3. Temperature at the installation site
When mounting the instrument it must be ensured that, taking into consideration
the influence of convection and heat radiation, no deviation above or below the
permissible ambient and medium temperatures can occur.
4. Pressurisation
Pressure surges must be avoided at all costs. Open the shut-off valves slowly.
5. Temperature increase through compression warming
Avoid the increasing of warming due to gas-compression. In these cases it may
be necessary to throttle the rate of change of pressure or reduce the permissible
medium temperature.
6. Equipotential bonding
The instruments must be connected to the equipotential bonding of the plant via
the process connection by the end user in the end use application. Avoid use of
electric insulating sealing materials.
7. Handling of materials
Avoid exposing the instrument to any substances or ambient conditions that could
negatively affect the instrument and the materials used. Avoid handling substan-
ces that are liable to spontaneous combustion. For a list of the materials used,
see chapter 3 "Specifications". The materials of wetted parts not listed there (e.g.
Hastelloy) are noted on the dial.
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Maximum permissible surface temperature of the
instrument (for the end application)
< 2/3 T
cloud
< T − 75 K − (reduction depending on the layer thickness)
layer
WIKA mode d'emploi manomètre, type 6 selon ATEX