11
4.2. Switching The Pump ON And OFF
When operating the pump gets hot.
The pump can be switched ON and OFF in any pressure
range. On switching off, the built-in high vacuum safety valve
to the vacuum plant closes automatically and vents the pump.
Minimum start-up temperature, in compliance with German
Industrial Standard DIN 28 426: + 12 °C.
On switching OFF (intake pressure < 750 mbar) the built-in
high vacuum safety valve to the vacuum chamber closes
automatically and the pump is vented.
4.3. Operating The Pump With Gas Ballast
If condensable vapors are pumped off, the pump must always
be operated with gas ballast. If the condensation exceeds the
water vapor capacity of the pump, a condenser should be
connected upstream. If no condenser is connected, the
condensate produced due to the difference in temperature
between the pump housing and pump body must be drained
at drain plug 43. The condensate produced inside the pump
can be observed at sight glass 44 as a rising operating fluid
level.
4.3.1. Standard Model
Gas ballast valve 45 is fitted with a sliding sleeve which, when
pushed towards the pump, opens the valve and when pushed
away from the pump, shuts the valve. Intermediate settings
are not possible.
4.3.2 Corrosive Gas Model
Gas ballast valve 45 is fitted with a dosing device and a
flushing gas connection. It has a sliding sleeve which opens
the valve when pushed towards the pump and shuts the valve
when pushed away from the pump. The dosing device is
closed when the groove in the dosing screw is in the horizon-
tal position; in the vertical position the dosing device is fully
open. A flow meter enables any intermediate gas volume
setting between fully open and fully closed to be made.
Flushing gas must be connected when
operating corrosive gas version pumps. The gas
ballast valve must be open. Flushing gas
pressure may not exceed 1.5 bar. Our
specialists would be pleased to give advice
regarding the type and volume of flushing gas required.
Gas ballast valve standard model
28 Support stand
45 Gas ballast valve with sliding sleeve
182 Pressure gauge
182 45
28
When the pump is at operating temperature, the pressure
gauge 182 indicates a operating fluid pressure between 0.8
and 2.5 bar. At a cold start (approx. 12°C), the pressure in the
pressure gauge may rise up to max. 6 bar. When the pump
temperature rises, the pressure drops to normal.
With operating medium F5, the pressure of the pump at
working temperature is set between 3 and 5 bar. When cold
starting, pressure rises upto 15 bar.
In continuous operation the level of operating fluid must be
checked daily at the sight glass 44 and the pressure at
pressure gauge 182.
To Next Page