6) Freeze-drying process
After attaching the specimen container, degree of
vacuum rises gradually. Frost formation in white
on the surface of the container is a desirable status
during this processing.
* If granular frost formation is found inside the cold trap,
during freeze drying process, vacuum leakage might
have been occurred. Check the joint between
the specimen container and adaptor.
7) Completion of freeze-drying
As drying process proceeds, frost formation on
the surface of the specimen container begins
to melt. When the surface is dried sufficiently,
turn the vacuum cock with the marking of “VENT”
downward to regain normal pressure inside the
container. And detach the container.
- 25 -
8) Defrost Operation
Press Defrost switch for 3 seconds or more.
Hot gas flows outside the trap to melt the frost
adhered inner walls of cold trap. (Defrost
processing is started.)
At this point, the vacuum pump stops automatically.
When the pump stops, the safety valve (leak valve)
operates to regain normal pressure inside the trap
simultaneously.
* If normal pressure is not regained in the trap, or,
this process is too slow, leak filter may be clogged.
In such case, since it may result in
reverse flow of oil or other equipment failure, replace
the filter referring to Sec. 7-1.3, Leak Filter
Replacement
Turn the cock rightward to
regain normal pressure.
And detach the container.
VENT
VAC.
▽
△
▽
▽
VAC
.
Hold the specimen container with hands
not to drop it after releasing vacuum
CAUTION
Ice formed on the inner walls
of trap begins to melt.
Hot Gas
Trap Barrier
Cooling Part
After the defrosting operation, make sure that
the ice is removed from the cold trap. And
turn off the Defrost switch.
To interrupt defrosting, press Defrost switch for
3 seconds or more.
* As for FDU-1110, when approx. 40 minutes passed
after turning on the Defrost switch, or trap temperature
reaches 40
°
C, the refrigerator is turned off
(automatic stoppage), and the Defrost switch lamp
goes off to notify interruption of defrosting operation.
As for FDU-2110, when approx. 30 minutes passed after
turning on the Defrost switch, or trap temperature
reaches 50
°
C, the same operations as FDU-1110 are
executed.
* Do not execute defrosting operation for
processes other than ice-melting using hot gas.
Be careful of skin burn
CAUTION
Depending on the conditions such as environment
temperature in use and amount of dehumidification,
inner walls of cold trap may have a very high
temperature. Be careful not to touch these walls
during operation of hot gas, and right after
the operation.
Completion of freeze-drying
Frost (Ice)
During freeze-drying
Dried specimen
