Bartec APEX (APC) 07-3704 Series, Operating Instructions Manual

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Product description
APEX / SILAS
Pressurized Cabinet
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3 Product description
General
The Ex p type of protection, referred to as “pressurized enclosure”, is based on
the measure of purging out any explosive gases that are in a closed enclosure
and then generating and maintaining a level of pressure that is higher than that
of the ambient atmosphere. As the pressure inside the enclosure is higher than
the atmospheric pressure, it is not possible at any time for explosive gases to
penetrate the inside of the enclosure. This creates an Ex-free area in which
electrical devices that are not themselves explosion-proof can be mounted and
operated.
The APEX (SILAS) pressurized cabinets described in these operating
instructions function on the principle of “pressurized enclosure with leakage
loss compensation”. Specifically, this means that an overpressure in an
enclosure is maintained by the addition of purging gas to compensate for the
leakage losses from the enclosure. In addition a defined quantity of purging gas
can be introduced also during the operating phase, depending on application;
constant purging.
To ensure that an explosive atmosphere that has penetrated during downtimes
cannot become a hazard, the pressurized cabinet must be flushed with purging
gas (compressed air or inert gas) before commissioning. The quantity depends
on the inspection carried out during initial commissioning. The rate of flow is
measured or determined at the outlet of the pressurized enclosure.
After purging, the Ex p protected application is switched on. Depending on
version of the APEX (SILAS) pressurized cabinet, the activation may take the
following form.

APEX pressurized cabinet type, pxb
Automatic connection via the Ex p control unit or, in the case of larger
switching capacities, via a separately certified switching module or
indirectly from the Ex safe area.

APEX pressurized cabinet type, pyb
Automatic connection via the Ex p control unit or, in the case of larger
switching capacities, via a separately certified switching module or
indirectly from the Ex safe area.
The automatic connection can also be realised by manual connection,
whereby the switching module must be certified separately.

SILAS pressurized cabinet type, pzc
Automatic connection via the Ex p control unit or, in the case of larger
switching capacities, via a separately certified switching module or
indirectly from the Ex safe area.
The automatic connection can also be realised by manual connection,
whereby the switching module must be certified separately.