JAVAC BULLDOG A2L, Safety Instructions & Operation Manual

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5.0 USING THE GAS BALLAST
5.1 The Gas Ballast valve allows a controlled amount of air to enter the compression cycle, diluting
the condensable vapor (i.e. water), then exhausting it out of the compression chamber before it
condenses and accumulates in oil reservoir.
FOR EXAMPLE: In a wet system, the partial pressure of water increases as the pump removes
the air. When the partial pressure of the water vapor of the system gas reaches its Saturation Vapor
Pressure (SVP) during the compression cycle of the pump, it condenses back into a liquid, mixes with
the oil, and the pump WILL NOT achieve vacuum better than the SVP of the water. This is because
the water evapo-rates from the oil on the suction cycle and then re-condenses back into the oil
during the compression cycle. However, if you reduce the partial pressure of the water vapor during
the pump’s compression cycle with a measured and controlled amount of non-condensable gas, the
water vapor WILL NOT reach its SVP during compression and will therefore be discharged from the
pump. The gas ballast allows a controlled amount of atmospheric gas into the compression cycle
of the pump, thus “diluting” the water vapor that is being compressed and exhausting it out of the
compression chamber before it condenses.
5.2 The gas ballast valve can be opened or closed at any time during pump operation after the
operating temperature has been achieved.
5.3 During the evacuation process, the gas ballast will minimize the effect of vapor condensing within
the pump, but it may slightly reduce ultimate vacuum. If ultimate vacuum is required, the gas ballast
may be “closed” during the evacuation process.
5.3 The gas ballast valve is located on the top of the vacuum pump. Normal operating condition is
about 1/4-1/2 turns counter-clockwise, at which a slight “popping” noise occurs. The valve when
shut down must only be finger tight otherwise the precision valve seat may get damaged.
NOTE: Excessive high volumetric pressure pump down may result in residual oil around the gas
ballast valve. This is normal. Clean as necessary.
6.0 SHUT DOWN PROCEDURE
6.1 CLOSE the manifold valve between the pump and the system.
6.2 “OPEN” gas ballast valve for a few minutes before shut down. This allows the pump to purge
condensable vapors.
6.3 Turn power switch OFF.
6.4 If necessary, drain oil while the pump is warm.