Section 7 Maintenance
7-2
ULVAC CRYOGENICS INCORPORATED
Inside the compressor unit, some areas remain hot immediately after the shutdown.
Wait for at least 15 minutes in order to perform maintenance work safely. Failure to
observe this warning may result in severe body injury.
When adjusting helium pressure, it is necessary to perform the work while inside of the
compressor unit is in room temperature. Perform this work after cooling down the
compressor for three hours.
Follow the steps below to replace adsorber
1. Ensure that each equipment and device in cryopump system is safe to replace
adsorber.
2. Turn off the compressor unit by turning OFF the breaker inside the distribution panel at
the equipment side. Make sure that the power is off, and lockout –tagout the breaker
for safety.
3. Disconnect the flexible hoses from the “SUPPLY GAS” and “RETURN GAS”
connectors at the rear panel of the compressor. Observe the disconnecting
requirements below. Refer to “Section 4.3 Connecting and disconnecting helium
flexible hoses” for disconnecting method.
NOTE: When disconnecting flexible hoses from the connectors, use two single-ended
wrenches (bolt width 26mm, 30mm).
4. Remove the nuts of the connectors at the rear panel of the compressor with the
spanner (Figure 7-1).
5. Remove the seven screws of the rear panel with a proper screw driver and remove the
rear panel (Figure 7-2 and 7-3).
6. Disconnect the self-sealing coupling from the adsorber with two spanners. The
coupling is connected to the flexible hose above the bottom plate inside the
compressor chassis (Figure 7-4). See Figure 7-5 for usage of spanners to disconnect
the coupling.
Disconnect the coupling quickly to minimize helium leakage.
7. Remove the bolts that secure the adsorber to the base of the compressor with the
proper spanner (Figure 7-6).
WARNING
Do not disconnect flexible hoses while the cryopump is in low temperature. Doing so
may raise the internal pressure as inside of the refrigerator unit warms up, resulting in
helium leakage by activated safety valve.
CAUTION
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