page 39 of 91 USB-QFLCII-14804/0
WARNING
If the flap blade is closed during operation due to an explosion, a signal is sent to
the monitoring panel and an emergency shutdown is initiated!
If a signal is received from the closed-position sensor at the monitoring panel
during operation, an immediate emergency shutdown must take place through
the monitoring panel!
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Monitoring during sys
tem start A vacuum is created during fan start-up which keeps the flap blade open. The
time interval prior to flap blade opening depends on various system
parameters. Since the flap blade opens with a time delay after the system start-
up, the monitoring of the closed-position sensor with a "0" signal may only
occur after a time delay. If time-delayed evaluation during system start-up does
not occur, a malfunction and emergency shutdown would take place! To avoid
these malfunction messages during start-up, it is necessary to implement a
time-delayed evaluation of the closed-position sensor at the monitoring panel.
WARNING
Time-delayed evaluation of the closed-position sensor may only occur
at system start-up!
If a time-delayed evaluation of the closed-position sensor were to occur during
system operation, there is the possibility that an explosion could be detected too
late and an immediate emergency shutdown could not take place.
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4.4.3 Wear and tear sensor requirements
The intrinsically safe wear and tear sensor requires the use of an approved
switch ampli
fier (see Section 11, External Documents,Technical Data Switch Amplifier).
Wear and tear sensor
signal If the wear and tear sensor indicates too much erosion, a corresponding
malfunction signal should be displayed at the monitoring panel. The system
can continue operation until the next scheduled shutdown and an emergency
shutdown is not necessary.
If the system is shut off after a wear and tear signal malfunction
message, you must thoroughly inspect the inlet isolation device for wear
and tear. The flap blade, wear and tear sensor and all other worn parts
must be replaced or the entire inlet isolation device should be replaced,
depending on condition. Repairs or replacement should only be
completed by authorized professionals.
Prior to start-up again, the wear and tear sensor must be replaced!
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