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Two 9-10 mm internal diameter rubber or plastic
tubes from the water supply must be fitted to the
two dedicated nozzles.
NOTE
These tubes must be held on the respective noz-
zles using hose clips to avoid that the tube(s) gets
loose or disconnected during operation.
Cooling may be carried out either through an open
circuit with eventual discharge of the water, or us-
ing a closed circuit cooling system.
The water temperature must be between +10°C
and +35°C, with an inlet pressure between 3 and 5
bar. In any case the water flow must not be less
than 200 l/h.
The customer can alternatively order the 90° bend
water cooling kit, plastic model (969-9348) or me-
tallic model (969-9338).
NOTE
The water electrical conductance must be
µ
s/cm. When the conductance is higher, in closed
water circuit, the use of up to 20% of Ethyl-Glycole
is suggested.
PUMP PURGING AND VENTING
The Turbo-V 2K-G pump is equipped with an inte-
grated purging and venting valve device. Both
valves are fed through a single gas port, with 1/8
NPT thread or Swagelok connector.
Purge and Vent Installation
To install the gas purge and vent line it is neces-
sary to unscrew the purge/vent port cover, and
then connect the gas line.
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 line to
the pump.
The purging device automatically provides 20
sccm when fed with 1 bar (14 psi) absolute (at-
mospheric pressure).
!
CAUTION
To prevent bearing damage, Varian suggests a
minimum purge gas flow rate of 20 sccm (0.33
mbar l/s). This value can be exceeded, according
to the process requirements. Please contact Var-
ian for specific applications.
The purge gas throughput of 20 sccm with the rec-
ommended forepump allows to achieve a high
vacuum pressure in the 10
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.
Close the corrosive gas flow into the system.
2.
Leaving the Turbo-V 2K-G pump and the
backing pump running and the purge gas
flowing, wait for enough time to evacuate the
corrosive gas from the system.
3.
Turn off the Turbopump.
4.
Open the Turbo-V 2K-G vent electro valve up
to the atmospheric pressure in the system.
5.
When the Turbo-V 2K-G pump and the back-
≤
500
ing 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.
1. Purge gas line
2. Pressure regulator
3. Purge and vent port
4. Forevacuum pump
5. Turbopump
6. Water line
94
TECHNICAL INFORMATION
-6
mbar range.
VACUUM TECHNOLOGIES
Purge and vent layout
87-900-968-01(C)
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