Operating Instructions for film dessicators
NOTE FIRST: On no account allow a throughput of air into the system with the pump running. This may be done by not closing taps or not sealing the dessicator doors properly. The pump is designed to run continually, but not with a large airflow, which will result in damage.
Each chamber should have a cartridge of zeolite dessicant in the base.
TO REMOVE/REPLACE A FILM CASSETTE
Use the chamber marked "open next".
Isolate the pump from the chamber by twisting red knob at the top of the chamber clockwise while pushing it down.
Open the side air inlet (silver tap) of the chamber allowing it to reach atmospheric pressure.
Remove the chamber door and take a delivery box of cassettes from the rear of the chamber, placing the new, undessiccated film to the front of the chamber.
Secure the chamber door (check that the O ring and plate are free of grit) by screwing on, gradually and alternately at least two of the black knobs, ensuring that the plate is flush with the chamber.Close (clockwise) the silver air intake to the right hand side of this chamber.
BEFORE opening the chamber to the pump, TEMPORARILY isolate the other chamber, by closing the red valve on the other chamber. DO NOT FORGET to re-open it once the vacuum is re-established, otherwise the films will not be pumped.
To open the first chamber to the pump, turn the red knob anticlockwise while pulling it up.
Switch on the gauge readout next to the turbo-frequency controller and press TM1 to read the pressure in the dessicator open to the pump. This should, if no leaks are present read approx. 10-2 mbar. Once this is reached, open the second dessicator to the pump via the red knob. Switch off the gauge once you are sure everything is sealed. If you need to open both chambers, it will take longer to establish a good vacuum, because of the large pumping volume.
Move the "open next" sign to the dessicator that was not opened, checking to make sure that the valves to both chambers are open.
Leave the film to dessicate for at least 24 h.