6
4.3 Intermittent Operations
To prolong the life of diaphragm pumps, intermittent
operations can be selected with lesser gas throughputs of
< 0.18 mbar l/s. This means that, dependent on the turbo
pump power take-up, the backing pump will be switched on
and off. Turbo pump power take-up is dependent on the fore-
vacuum pressure and gas throughput.
– By comparing the power take-up with an upper and a
lower limit value, the relative switch-on duration with
lesser gas throughputs can be reduced to approx. 1 to 60%
– To avoid too frequent switching on, the buffer volume in
the fore-vacuum line should amount to
<
0.5 liter from
approx. 0.018 mbar l/s.
Possible intermittent operations variations are shown in the
following diagram:
Connection of Diaphragm Vacuum Pump with with relay box on TC 600 for intermittent operations
roughing pump
MVP series
Relaybox
PM 041 937 GT
4. Operations
4.1. Important Information
Before starting, ensure that impermissibly high
pressures cannot build up on the pressure side.
Interchanging the connections causes
dangerous excess pressure levels.
The pumps should only start, when the pressu-
re difference is max. 1 bar between admission and exhaust,
because the motor will be blocked and damage.
When the pump is running, surfaces and motor
casing become hot.
WARNING
CAUTION
4.2 Switching ON/OFF The Pump
The pump can be switched on and off at all times.
Prevent internal condensation, transfer of
liquids or dust. The diaphragm and valves will
be damaged, if liquids are pumped in significant
amount over lengthy periods!
If the pump is subjected to condensates it
should be allowed to run for a few minutes
under atmospheric pressure before switching
off.
CAUTION
