accumulated moisture from draining down the
secondary line towards the pumps. All main
lines should slope away from the receiver tank
and pumps. Any low points in the piping should
be equipped with drains to remove accumulated
moisture and prevent condensation from
entering the pump.
A suitable 5 micron air inlet
fi
lter is provided
with each pump to protect it from incoming
particulates.
A knock-out pot or a drip leg with a drain is
occasionally provided if the gas stream contains
any liquid or vapor that will condense in the
piping. If the system has a knock-out pot or a
drip leg, the knock-out pot or drip leg must be
drained often to prevent liquid from entering
the pump(s).
2.7 Electrically Controlled Intake
Valve Actuator
Each vacuum pump is equipped with an
automatic purge system to
fl
ush any gases
from the pump to prevent condensation as the
pump cools. The purge system incorporates an
electrically controlled automatic isolation valve
for each pump. Therefore, there is no need for
an air supply to operate the actuator(s). Each
electric actuator is pre-wired at the factory
directly to the control panel.
When the power is brought back on to the
vacuum system after a power shortage, the valve
will go to the closed position unless the pump is
running and not in purge.
2.8 Exhaust
Piping
A
fl
exible connector must be installed on each
exhaust port of the vacuum pump before
connecting to the main exhaust line leading
outdoors. Additionally, a drip leg must be
installed at each exhaust port connection to allow
for the draining of any accumulated moisture.
The exhaust line must be piped outside of the
building. To ensure that no restriction of air
fl
ow
will occur, size the piping according to Table
2.2. The outside pipe must be turned down and
screened to prevent contamination, especially if
located on the roof.
Shut-o
ff
valves located on the exhaust discharge
side of the pump(s) are not recommended. If
shut-o
ff
or check valves are installed, special care
must be taken to make sure the pumps cannot
start unless its check valve and any shut-o
ff
valves associated with that pump are open. Any
exhaust discharge valving must be interlocked to
prevent operation of the pump when the valving
is closed. Failure to abide by this instruction will
void the pump warranty.
CAUTION:
Do not allow liquid to back up into the pump
from the exhaust piping.
WARNING:
The vacuum exhaust vent must be located
away from air intakes, doors, and openings
in the buildings to minimize possible
contamination to the facility.
WARNING:
Do not touch the exhaust system when the
pump is, or has recently been, in operation.
The exhaust system temperature can reach
high temperatures. Therefore, it should be
insulated for personnel protection.
WARNING:
Do not use soft solder on the exhaust piping
connections.
Lubricated Rotary Vane Laboratory Vacuum Systems
4107 9021 88.01
2-4
