Polycold Cryochiller Operation
Installation and Operation Manual Operating the Polycold Cryochiller with a Cryobaffle
Brooks Automation
214072 Revision B
6-11
3. The unit automatically goes into Standby when Defrost is complete.
Operating the Polycold Cryochiller with a Cryobaffle
An optically transparent cryobaffle enhances the water vapor pumping speed of the turbomolecular
pumps and an optically opaque cryobaffle minimizes oil backstreaming from oil diffusion pumps. Back-
streaming is the process of hot vapor migrating and condensing on cold surfaces. When an oil diffusion
pump is in operation, the pump oil heats up and hot oil vapor can travel opposite of the pumping direc-
tion and condense on the interior vacuum chamber walls and contaminate the system.
Standby and Cool Modes
1. Switch the unit to Standby using the unit's control panel or remote control.
2. If the compressor switch is turned OFF, turn the switch to ON.
3. When in Standby, the refrigeration unit cools the refrigerant so the unit is ready to go into Cool
mode.
NOTE: If the unit is off for more than 12 hours, it may take up to 30 minutes after going into Standby
to attain complete precooling.
4. Evacuate the vacuum chamber where the cryobaffle is installed to at least 0.01 torr (1.33 Pa).
5. From Standby, select Cool and allow the cryobaffle to cool down.
6. Turn on the high vacuum pump. It is not necessary to wait until the cryobaffle has cooled down.
Defrost Hazard
If large amounts of water are collected during the vacuum cycle,
liquid or ice may drop from the cryocoil during Defrost.
You may need to provide a drip pan or similar device to prevent liq-
uid water from accumulating in an undesirable location
NOTICE
Dual Polycold Cryochiller Defrosting
When defrosting one circuit while the other circuit is in Cool, the temperature of
the circuit in cool may increase.
Review the required temperatures for the affected process to make sure the
warming does not affect the process. If the temperature change is not accept-
able, wait until the completion of the cool process before performing Defrost.
Both circuits may be defrosted at the same time.
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