Cryomech LNP-40, Инструкция по установке, эксплуатации и текущему обслуживанию

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Routine Maintenance
8-4
CAUTION
Venting more than 5 PSIG (.34 bar) of helium per minute will lead to improper oil
migration within the system. If this condition occurs, factory service will be required.
This procedure should only be used to vent small quantities of helium from an
overcharged system.
1) Make sure the service valve is closed. See Figure 8-2.
2) Attach the small service Aeroquip
®
coupling to the service access port.
3) Open the service valve slowly. Do not vent more than 5 PSIG (.34 bar) of helium per
minute.
4) After venting the helium, close the service valve and remove the service Aeroquip
®
from the service access port.
8.6 Recharge helium
Required tools and equipment:
Quantity Description Comment
1 3/4” Open end wrench
For Aeroquip
®
coupling
1 Service Aeroquip
®
coupling For service access port
1 Vacuum/charging station For adding helium
CAUTION
When adding helium, the helium must be 99.999% pure. Contamination by other
gases will result in the freezing of the contaminant gases in the cold head because
their freezing temperature is much higher than that of helium. Contaminants in the
helium charge will severely degrade the cold head's function and it will require factory
servicing.
Contamination of the helium by other gases is a common cause of premature failure
and, unless resulting from a system failure, is not covered by the warranty.
This procedure should be performed with the helium compressor shut down. Adding
helium is possible whether or not the cold head is attached to the helium compressor.
Both the service access and service valve are connected to the low-pressure manifold of
the helium compressor.
1) Turn the helium compressor off.
2) Use only high purity helium with a minimum purity of 99.999%.
3) Check that the helium source and regulator are capable of pressurizing to the desired
pressure.
4) Make sure the service valve is closed.
5) Attach the service Aeroquip
®
coupling to the service access port.