Description
14
GA03108_002_C1 - 04/2018 - © Leybold
When operating the pump with a frequency converter, then generally the
drive motor of the fan must be operated at the normal mains frequency.
1.1.3 Pressure Balance Line
The RUVAC WSU has an integrated pressure balance line. It links the dis-
charge and intake flanges via a pressure balance valve.
If the pressure differential between the flanges is too large, the valve opens.
Some of the gas which has already been pumped then flows back through
the line to the intake flange.
The valve is weight- and spring-loaded so that it works with both vertical and
horizontal flow of the pump.
In the case of 50/60 Hz operation and due to the pressure balance line, no
additional controlling equipment will be needed to protect the pump against
pressure differences which are too high. The RUVAC WSU pumps can then
be switched on together with a backing pump at atmospheric pressure. Thus
the pumping speed of the pump combination is increased also at high intake
pressures.
Some models are equipped with an ACE shock absorber in the pressure
balance line. In the case of pressure bursts this prevents the valve from
making contact at the cover. This reduces valve noise and increases its dura-
bility.
The pressure balance valve will not protect the pump from thermal over-
load if opened continuously.
NOTICE
Fig. 1.4 Schematic diagram of a Roots pump with pressure balance line
Pressure balance valve
Pressure balance line
