ULTRASOURCE ULTRAVAC 2100, Owner'S Manual

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had sufficient time to return to the oil sump.
NOTE: The oil separated by the exhaust filter
element forms droplets on the outside of the exhaust
filter which collect at a low point in the upper half of
the exhaust box. From there the collected oil is
drained back to the oil sump via an oil check valve
(Pos 275) which opens on R5 RA Model Pumps
when the pump is shut off. It is necessary to shut off
the RA model pumps after every 8 hours of operation
to allow the check valve to open. If the pump is not
shut off after this time period, it is possible to starve
the pump of oil since the oil is not allowed to drain
back into the oil sump and/or oil droplets may be
blown out of the exhaust. If the pump is operating at
high pressure it may be necessary to shut it down
sooner than 8 hours.
On R5 (Standard) RC Model Pumps, the collect-
ed oil is drawn continuously during operation of the
vacuum pump to the inlet flange (Pos 260) via the
oil return line (Pos 290). The oil return line is con-
nected directly to the area of the exhaust box, down-
stream of the exhaust filter, which is at atmospheric
pressure. Therefore, a constant amount of air is
sucked into the pump which is an additional reason
that the R5 Standard Series Pumps do not achieve as
low a vacuum as the R5 Series Super Vacuum
Pumps.
2.2 Gas Ballast
All RA Series pumps are equipped with a gas
ballast valve. The gas ballast valve (Ref. 440) is
located between the inlet port and the exhaust box.
RA Series pumps up to size 100 are equipped with a
permanent gas ballast which cannot be shut off
unless the sintered filter is removed and the orifice
plugged. Larger pumps are equipped with an
adjustable gas ballast valve.
The adjustable gas ballast valve should normal-
ly be left open. Its primary function is to prevent
water vapor from condensing in the pump.
Condensation causes emulsification of the oil, loss
of lubricity, and possible rotor seizure.
2.3 Stopping Pump
To stop the pump, turn off the power. The pump
has a built-in anti-suck-back valve (Ref. 251 thru
255) to prevent the pump from rotating backwards
when it is shut off.
Install an automatic operated valve (such as a
check valve) in front of the pump, if more than one
pump is pumping on the same line or if there is a
sufficient volume of vacuum in the system to cause
the pump oil to be drawn into the piping when that
pump is shut down.
All R5 Series pumps are vented internally to
atmospheric pressure through venting holes which
are next to the exhaust valve assembly.
2.4 Water-Cooled Pumps
Water-cooled pumps are cooled by circulating
the oil through a shell-and-tube type heat exchanger.
The circulation of the pump oil through the shell is
created by vacuum in the pump, but the circulation
of the cooling water through the tubes is thermostat-
ically controlled. The flow rate of the cooling water
is controlled by a thermostatically activated valve
that senses, through a capillary bulb mounted in the
exhaust box, the pump's oil temperature as it is dis-
charged from the compression chamber. The valve
will open at its set point and close at approximately
3°F to 5°F below the set point. The valve set point is
adjustable as follows:
(a) Rotate the valve adjustment screw counter-
clockwise to cause the valve to open at a higher
temperature.
(b) Rotate the valve adjustment screw clockwise
to make the valve open at a lower temperature.
The thermostatic valve can be manually opened
by inserting a screwdriver under each side of the
spring guide and prying the spring and guide upward
away from the valve body.
Caution: Do not use the anti-suck-back valve
as a check or shut-off valve for your vacuum sys-
tem. Do not depend on the anti-suck-back valve
to prevent pump oil from migrating through the
inlet into the system when the pump is shut
down.
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