Brooks On-Board 8, Installation And Maintenance Instructions Manual

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Cryo-Torr 8600 Compressor Operation, Installation and Maintenance Guide
©2013 Brooks Automation Inc. Pub. No. 8040564, Rev. AA, 01/15/13 ECO No. 64541 4-11
All On-Board GLE Cryopumps that are cold must be decontaminated. If
they are cold and not decontaminated, then gases frozen in these On-Board
GLE Cryopumps will re-contaminate the helium gas when they are
warmed up.
Method # 2 Decontamination of Only Cold Cryopumps
If time is critical, then an alternate method of decontamination, using
Method 1 as a basis may be used. This procedure will also remove gaseous
contaminant in the system.
If certain On-Board GLE Cryopumps are warm in Step 1 then they can
remain at room temperature (i.e. over 290K). With the compressor on and
cold On-Board GLE Cryopumps left on, run these “warm” On-Board GLE
Cryopumps for 5 minutes. Running these “warm” On-Board GLE
Cryopumps for a short time will move any concentrated contaminant out of
these coldheads into the compressor. The contaminants will then be carried
to the cold On-Board GLE Cryopumps where they will be frozen.
In this method, the following Steps replace the corresponding Steps in
Method 1:
Step 1 - Method #2
Any On-Board GLE Cryopumps on the same manifold which are running
should have been running below 25K for at least 30 minutes. Any pumps
warmer than 290K should be kept warm. Continue with Step 2 even if any
pump does not cool below 25K (its performance may already be affected
by contamination). Close the high vacuum valves to isolate the On-Board
GLE Cryopumps from the vacuum chamber.
Step 17 - Method #2
Repeat Steps 10 - 16 for each On-Board GLE Cryopump which is not
above 290K.
Method # 3 Grouped Decontamination using Manifold
The time required to decontaminate each On-Board GLE Cryopump in
Method #1 after it is cooled and warmed up is about 30 minutes. If time is
not available to decontaminate each On-Board GLE Cryopump in
sequence, then the alternate is to decontaminate all On-Board GLE
Cryopumps together, i.e.:
Grouped Decontamination . At least one of the
On-Board GLE Cryopumps must be cold. The decontamination is
performed from the compressor side of the common supply and return
manifolds.
In this method the following Steps replace the previous Steps: