Models 947, 948 and 960 Leak Detectors Operations and Service Manual
4-10
4.2.3 Liquid Nitrogen Cold Trap (Models 948/960 only)
The trap should be refilled with liquid nitrogen (LN
2
) as needed. A typical time frame for
refilling is every 14 hours, depending on usage. During normal usage of the 948/960
Platform leak detector, water vapor and other contaminants build up on the surface of the
nitrogen trap.
To clean the cold trap:
1. Shut down the machine completely.
2. After approximately 30 minutes, slowly open the vent valve on the top of the Liquid
Nitrogen trap to vent the trap.
3. Don protective gear, such as
loose
fitting
gloves and eye or face shield,
and remove the
cold trap.
WARNING
Liquid nitrogen causes burns upon contact.
4. Clean the trap with soap and water only after it has warmed up to room temperature.
5. Rinse it well and dry it completely inside and out using a lint free cloth.
CAUTION
The outside of the cold trap must be completely dry or ice will
form and can be dragged into sensitive equipment when the
leak detector is turned on.
6. Once the trap is clean, replace it in the 948/960, and close the vent valve on the top of
the Liquid Nitrogen trap.
7. To re-establish operation, carefully refill the trap with LN
2
, using the safety procedure
above, and follow normal startup procedures for Models 948/960.
Summary of Contents for 948
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