SP Scientific Freezemobile Series, Operator'S Manual, Page: 37 / 54

VirTis Freezemobile 25L and 35L Optional Components
Rev 005, 02/12 27
© SP Scientific 2012
To operate a liquid nitrogen trap:
1. Enable the condenser and wait for the system to reach operating
temperature.
2. Remove the plastic cover from the stainless steel vessel and add a small
amount of liquid nitrogen to the center well. If adding liquid nitrogen from a
tank, use adequate ventilation to protect from gaseous vapors.
Note: The liquid nitrogen will expand and bubble when it meets the warm center well.
Wear protective eyewear and gloves to avoid contact with skin.
WARNING! LIQUID NITROGEN CAN CAUSE SEVERE CRYOGENIC BURNS. EXERCISE CAUTION
WHEN HANDLING. WEAR PROTECTIVE GLOVES AND AVOID SKIN CONTACT.
3. Replace cover and wait one minute.
4. Open center well and slowly fill with liquid nitrogen (
i.e.,
2.8 or 5 liters,
depending on capacity).
5. Open valves 1 and 2, and close valve 3 (see diagram).
6. Enable the vacuum and wait until vacuum pressure reaches 100 mT.
7. Trap is now in operation. Liquid Nitrogen evaporates rapidly over time. Check
center well often and refill with liquid nitrogen as needed.
Defrost
Accumulation of condensed vapors can result in a loss of vacuum. This can usually be
remedied by defrosting the trap. To check if the trap requires defrosting, isolate the
trap (close valves 1 and 2 and open valve 3) and break vacuum to the trap by
removing the drain plug from the drain hose (located under the stainless steel vessel).
Lift the center well slightly. If the well cannot be moved easily, defrosting is required.
To defrost your trap:
1. Remove any remaining liquid nitrogen from the center well.
2. Place a container under the trap and remove the drain hose plug.
3. Remove the center well and rinse off any remaining condensate.
Note: Adding hot water to the center well can accelerate melting of condensate.
4. Rinse the interior of the trap. Insert ¾-inch diameter plugs in the vacuum inlet
and outlet ports before rinsing the trap. Water in the vacuum line can cause
poor vacuum and may damage your pump.
5. Dry the trap and reassemble. Remove any plugs from the ports and replace
the drain line plug.
6. Rinse all stainless steel parts with a mild detergent or a solution of baking
soda and warm water after each defrosting to neutralize any acids.
Note: Never allow thawed condensate to remain in the trap.