Emerson Vilter PLC, Руководство по эксплуатации

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Section 2 • Operational Descriptions
Blower Package PLC Operation Manual •Vilter/Emerson • 35391BLP
GAS SCRUBBERS
A gas scrubber (or knockout drum) is a vessel with a vane
pack and/or coalescing elements installed to remove
moisture and other contaminants from the gas stream.
Gas scrubbers may be installed on the suction side or
discharge side of a blower package (if an aftercooler is
used, the scrubber is installed downstream of the after-
cooler). A condensate pump or solenoid valve drains ac-
cumulated moisture from the vessel.
Gas scrubbers include the following devices:
• Pressure transducers on the inlet and outlet of the
vessel – used to measure pressure drop across the
demister pad or coalescing elements to help deter-
mine when to clean or replace.
• Level switches to monitor the condensate level:
• LSH (High Level) – when liquid level reaches the
LSH level switch, an alarm is annunciated on the
blower HMI.
• LSHH (High High Level) – when liquid level reaches
the LSHH level switch, an alarm or trip is annunci-
ated on the blower HMI. The alarm or trip action
is con
fi gurable depending on the site and location
of the vessel. If trip action is selected, the blower
will shut down if the LSHH is activated. Typically
the purpose of the LSHH is to alarm or shut down
the blower package to prevent bringing liquid into
the blower suction.
• LSLL (Low Low Level) – when liquid level drops
below the LSLL level switch, an alarm or trip is an-
nunciated on the blower HMI. The alarm or trip
action is con
fi gurable depending on the site and
location of the vessel. If trip action is selected,
the blower will shut down if the LSLL is activated.
Typically the purpose of the LSLL is to detect if the
liquid seal is lost to prevent introducing gas into
the condensate drain system.
• Condensate Drain System:
• A drain pump or solenoid valve will turn on when
the liquid level in the scrubber reaches the “Cutin”
level switch.
• The drain pump or solenoid valve will turn off
when the liquid level in the scrubber drops to the
“Cutout” level switch.
• Dual pumps may be used. Selection of Pump A or
B is made in the Con fi guration screen.