HELIX CTI-CRYOGENICS CRYO-TORR 100 Installation, Operation And Servicing Instructions page 37

b. Depressurize the cold head by slowly opening
the ball valve and allowing the helium to bleed
out slowly. Do not reduce the pressure to less
than 30 psig or the cold head may be further
contaminated.
c. Perform flushing steps a and b three more times.
d. Pressurize the cold head to the static charge
pressure of 245-250 psig (l690-1725 kPa)
and run the cold head drive motor for 10 to 30
seconds by actuating the controller
ON/OFF
switch.
e. Perform steps b through d three more times for
a total of20 flushes and a total of 4 drive-motor
runs.
9. Verify that the cold head is pressurized to the static
charge pressure of 245-250 psig (1690-1725 kPa).
10. Disconnect the maintenance manifold from the
helium-gas return and helium-gas supply lines.
11. Reconnect the helium-gas return and helium-gas
supply lines to the return and supply connectors
at the rear of the compressor. The cryopump is
now ready for operation.
7.5.2 Compressor
Decontamination Procedures
The procedure to decontaminate a compressor is similar
to the above procedure with certain exceptions.
• There is no need to operate the cryopump before
decontaminating the compressor.
• The maintenance manifold and flex lines will be
connected to the supply and return fittings on
the compressor.
7-5/7-6
-CRYOGENICS
HELIX TECHNOLOGY CORPORATION
1.
Depressurize the compressor (ifpressllrized)
SLOWLY
to 30 psig by opening the ball valve
on the maintenance manifold and allowing the
helium to bleed out.
2. Charge the compressor slowly to approximately
250 psig (1725 kPa) by opening the 1/8-inch valve
on the maintenance manifold.
3. Run the compressor for about 30 seconds.
4.
Repeat steps 1 and 2, one more time.
5. Disconnect the maintenance manifold from the
helium-gas return and helium-gas supply lines.
6. Reconnect the helium-gas return and helium-gas
supply lines to the return and supply connectors on
the cold head. The compressor is now ready for
operation.
For Your Information --
After connecting the compressor to the cryopump,
and operating the system for a period of time, it may
be necessary to decontaminate the cryopump as some
residual contamination from the compressor may be-
come trapped in the cold head.
If
the entire system
were reduced to zero psig (a broken flex line for
example), then the cryopump and compressor would
have to be decontaminated according to the decon-
tamination procedure section, beginning on page 7-4.