Table des Matières
Publicité
17
Technical Information
Pump Used with Corrosive Gases
Pump Used with Corrosive Gases
To prevent damage to the bearings, an inert gas must flow into the pump body
around the upper bearing towards the forevacuum line. To supply the inert
purge gas (e. g. nitrogen) to the pump through the purge port, connect a gas
purge valve between the pressure regulator and the pump.
Adjust the pressure regulator in order to read a gas flow rate of 0.1 to 0.8 mbar
l/s.
To prevent bearing damage, Agilent suggests a minimum purge gas flow rate of
CAUTION!
10 sccm (0.17 mbar l/s). This value can be exceeded, according to the process
requirements. Please contact Agilent for specific applications.
The purge gas throughput with the recommended forepump of 15 m
CFM) allows to achieve a high vacuum pressure in the 10-8 mbar range.
The recommended gas flow maintains a pressure into the pump body higher
than the forevacuum pressure.
The recommended procedure to vent the system and the pump avoiding the
contact between the pump bearings and the corrosive gas is described in the
following points:
1
2
3
4
5
318/328
Close the corrosive gas flow into the system.
Leaving the Turbo-V pump and the backing pump running and the purge
gas flowing, wait for enough time to evacuate the corrosive gas from the
system.
Turn off the Turbopump.
Open the Turbo-V vent port slowly until to reach atmospheric pressure in
the system.
When the Turbo-V pump and the backing pump are stopped and the
system is at at-mospheric pressure, for a better bearing pro-tection it is
advisable to leave the purge gas flowing into the Turbo-V pump, with the
chamber or the Turbo-V vent valve opened, to avoid system overpressures.
If the vent valve can't be kept opened, the backing pump should be left
operating.
TV 551/701 Navigator User Manual / 87-900-934-01 (P)
3
/h (11
Publicité
Chapitres
Table des Matières
