Oerlikon Leybold Vacuum 960 862, Operating Instructions Manual

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5 GA02319_002_03 - 07/2007 - © Oerlikon Leybold Vacuum
1 Description
SOGEVAC
®
pumps are designed for pumping of inert gases in the range
of rough vacuum, between atmospheric pressure and end pressure of the
pump.
When removing condensable vapours, a gas ballast valve (or 2) must be
installed.
1.1 Principle of operation
The SOGEVAC
®
SV630 B / SV750 B is a single-stage, oil-sealed rotary vane
pump.
The anti-suckback valve, gas ballast valve, exhaust filters, oil feedback
circuit, oil cooler and thermal switch are integrated functional elements of the
SV630 B. The pump is driven by a foot-mounted motor via four V-belts.
The rotor mounted eccentrically in the pump cylinder has three vanes which
divide the pump chamber into several compartments. The volume of each
changes periodically with the rotation of the rotor.
As a result of enlargement of the pump chamber that is open in the direction
of the intake port, gas is sucked in. The gas passes through the dirt trap
and the open antisuckback valve and enters the pump chamber. As the rotor
rotates further, the vane separates part of the pump chamber from the intake
port. This part of the pump chamber is reduced, and the gas is compressed.
At slightly above atmospheric pressure the gas is expelled from the chamber
via the exhaust valves.
Oil injected into the pump chamber serves to seal, lubricate and cool the
pump.
The oil entrained with the compressed gas is coarsely trapped in the bottom
part of the oil casing. Then fine filtering occurs in the 8 integrated exhaust
filter elements.
The oil trapped in the exhaust filters is returned to the stator via an oil return
line. To prevent gas flowing at atmospheric pressure from the oil reservoir
into the intake port, the oil return line is controlled by a float valve.
The oil cycle of the SOGEVAC
®
SV630 B is maintained by the pressure
difference existing between the oil casing (pressure above atmospheric
pressure) and the intake port (pressure below atmospheric pressure).
Unintentional venting of the vacuum chamber as well as oil suckback when
switching off the pump are prevented by the built-in anti-suckback valve.
Nevertheless, the anti-suckback valve does not guarantee th
e same safety as
one valve.
As an additional failsafe device a thermal switch is incorporated ; it measures
the temperature in the main oil cycle before the oil is injected into the pump
chamber.
Description