28 Instruction Manual QuickTOC
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ultra
IECEx 12E5119
3 Product
3.5 Explosion Protection Components LAR | PROCESS ANALYSERS AG
3.5 Explosion Protection Components
3.5.1 Overpressure system
The overpressure is established by the control unit F870S (1). The control unit ensures that the analyser
is constantly flushed by an inert gas. Through a proportional valve (2) the casing is constantly filled with
the inert gas to an overpressure rate in order to override all leaks.
At start-up, the control unit starts with a purging sequence to eliminate all potentially explosive gases.
During this sequence, the analyser remains shut down. All dead spaces over 20cm
3
are flushed.
After the successful flushing of the casing, the analyser (4) is switched on by means of interface relays
(3). Only at this point the connection to the consumer level is established.
An error leads to an alarm relay in the control unit.
For service or maintenance by trained staff, a bypass mode (protected by password) in the control unit
is set in place.
Fig. 13: Components of the overpressure system
2
3
4
1
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