Operation
25
6.5
Switching off and venting
Switching off
After the turbopump is switched off, it must be vented to avoid contamination due to par-
ticles streaming back from the fore-vacuum area.
Close the fore-vacuum line: Switch off the backing pump or close a fore-vacuum
valve.
Switch off the turbopump on the control unit or via remote control.
Venting (possibilities, see below)
For water cooling: Shut off the water supply.
Venting
Manually venting
Open the venting screw (included) in the venting connection of the turbopump about
one turn.
Venting with Pfeiffer Vacuum Venting Valve
Enable venting via the functions of the electronic drive unit.
Settings are possible via the RS-485 by using DCU, HPU or PC.
1)
When mains power is restored the venting procedure is aborted.
Basic information for the rapid venting
Venting of the vacuum chamber in two steps. Ask for details on individual solutions from
Pfeiffer Vacuum.
Vent for 20 seconds at a rate of pressure rise of max. 15 hPa/s.
– The valve cross section for the venting rate of 15 hPa/s must be adapted to the size
of the vacuum chamber.
– For small vacuum chambers, use the Pfeiffer Vacuum venting valve.
Then vent with an additional venting valve of any desired size.
Venting rotation speed
Switch off the pumping station
Mains power failure
1)
50% of the nominal rotation
speed
Venting valve opens for 3600 s (1 h,
works setting)
Venting valve opens for
3600 s (1 h, works setting)
