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SUGGESTED PUMP INSTALLATION
The following figure shows a suggested pump in-
stallation.
1.
Vacuum chamber
2.
Rough line
3.
Heater jacket
4.
ICE Turbo pump
5.
Heater cable
6.
Pump cable
7.
Pump controller
8.
Gas purge valve
9.
Solid state flowmeter
V1 Gate valve
V2 Rough valve
V3 Dry pump valve
V4 Vent valve
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 mini-
mum 3 minutes from the pump stop signal. Back-
ing pump should be left on for the first 30" of
venting to prevent pressure burst inside the tur-
bopump. A gate valve on the pump inlet is defi-
nitely suggested if dust is known to be present in
the process chamber.
Solid State Flowmeter must be used and the rela-
tive alarm signal on the controller must be inter-
faced on the system to indicate any low purge flow
condition. Proper actions must be taken on the
system when a low purge condition is present.
The special heater jacket should be used if con-
densable materials are known to be present during
the process. The heater jacket working tempera-
ture should be adjusted on the pump control unit
(see controller manual for reference). Ask VARIAN
for proper temperature setting. Heater jacket must
be always on even during start-up and shutdown.
Filtered cooling water should be used in closed cir-
cuitry. Tap water could be used in closed cooling
circuitry in addition of 40% of ethyl glicole. The
electrical conductance of the water must be < 500
µ S/cm. Tap water could be tolerated if its electrical
conductance is lower than 500
Pump and chamber at atmosphere
1.
V1, V2, and V4 closed; V3 open.
Start backing 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.
3.
Rough down to 10
4.
Close V2; open V3.
35
TECHNICAL INFORMATION
NOTES
µ S/cm.
-1
mbar or lower.
87-900-897-01(C)
-1
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