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Plug the IEC electrical power socket wired into the level meter into the solenoid valve.
The Cryojet will not give maximum stability unless the pressure in the dewar remains very
close to atmospheric pressure. The autofill system is supplied with a restriction in the fill
hose to prevent the pressure in the dewar rising. If you observe an unacceptable
fluctuation in temperature when the fill starts, then set the ball valve on your supply
dewar only partly open, to restrict the flow of liquid and gas when the solenoid valve
opens. If the temperature fluctuations are negligible but the fill is unacceptably slow,
then you may wish to remove or reduce the restriction. To do this, remove the fill hose
from the dewar, and unscrew the stainless steel compression fitting from the end of the
hose. The restrictor is a plastic plug with three holes, glued inside this fitting. You can
either drill a larger hole in this plug, or request a new plug with no restrictor from your
Oxford Instruments sales representative.
Note:
This will increase the temperature fluctuation caused by filling.
The autofill is ready for use. If the Cryojet dewar is below the FILL level, it will start to fill.
8.2
The Solenoid Valve
The valve is closed when no power is supplied to it. When the solenoid valve is energised
(open) for a long period it will become very hot. This is a safe operating temperature.
Normal valve operation is indicated by a sharp click. Sluggish operation indicates that
cleaning of the core assembly is required.
The valve can be opened by plugging it directly into the mains electricity supply, using a
suitable cable. The hose can then be used without the level meter, to transfer nitrogen
under manual control.
