Agilent Technologies TV 551 Notice De Mode D'emploi page 266

17 Technical Information
Pump Used with Corrosive Gases
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
-8
10
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
266/276
3
/h (11 CFM) allows to achieve a high vacuum pressure in the
mbar range. The recommended gas flow maintains a pressure into
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 atmospheric pressure, for a better bearing
protection 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 SEM Navigator User Manual / 87-900-958-01(G)