Roughing Operation; Pump And Chamber At Atmosphere; Pump Under Vacuum, Chamber At Atmosphere (Chamber Cleaning); Suggested Pump Installation - Varian Turbo-V 2000 ICE Instructions For Use Manual

Roughing Operation

Roughing of the vacuum chamber should be per-
formed through a separate line and not through
the Turbopump.
Typical roughing sequences are detailed in the fol-
lowing paragraphs (see the above figure).
NOTES
• Gas Purge must be always on. Even during the
pump start-up or shutdown, supply pressure on
gas purge valve must be > 1 bar (15 psig).
• Venting of the pump must be performed in
minimum 3 minutes from the pump stop signal.
Backing pump should be left on for the first 30"
of venting to prevent pressure burst inside the
turbopump. A gate valve on the pump inlet is
definitely suggested if dust is known to be pre-
sent in the process chamber.
• Solid State Flowmeter must be used and the
relative alarm signal on the controller must be
interfaced on the system to indicate any low
purge flow condition. Proper actions must be
taken on the system when a low purge condi-
tion is present.
• The special heater jacket should be used if
condensable materials are known to be present
during the process. The heater jacket working
temperature should be adjusted on the pump
control unit (see controller manual for refer-
ence). Ask VARIAN for proper temperature set-
ting. Heater jacket must be always on even
during start-up and shutdown.
• Filtered cooling water should be used in closed
circuitry. Tap water could be used in closed
cooling circuitry in addition of 40% of ethyl gli-
cole. The electrical conductance of the water
µ
S/cm. Tap water could be tol-
must be < 500
erated if its electrical conductance is lower than
µ
500 S/cm.

Pump and chamber at atmosphere

1. V1, V2, and V4 closed; V3 open. Start back-
ing chamber and Turbo at the same time.
2. When Turbo at Normal operation close V3,
open V2 and rough the chamber up to 10
mbar or lower.
3. Close V2; open V3.
4. Open V1 and Start process.
Pump under vacuum, chamber at atmosphere
(chamber cleaning)
1. V1, V2 and V4 closed; V3 opened.
Turbopump is in Normal operation.
2. V3 closed; V2 open.
-1
3. Rough down to 10
4. Close V2; open V3.
mbar or lower.

Suggested Pump Installation

1. Turbo-V controller
2. Vent valve
3. Vacuum pump shut-off valve (optional)
4. System vent valve (optional)
5. Vacuum chamber
6. Ionisation gauge
7. Fore-vacuum pump connecting flange
8. Oil mist eliminator
9. Fore-vacuum pump with internal one-way
valve
10. Fore-vacuum pump control relay
11. Connection for water cooling
-1
12. Roughing line with valve (optional)
13. Turbopump
14. Flexible connection
15. Solid state flowmeter
16. Gas purge valve (integrated into the pump)
17. Heating jacket
34
TECHNICAL INFORMATION
87-900-915-01(E)