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2.2.1 Removing air from Vessel 1
Once the system has been pressurised, tap A on Vessel 1 can be opened. It is possible
to bubbled helium gas through the sample liquid against the non-return valve, V13. If
this is required, first ensure that valves V5, V7 and V8 are closed. Open valves V10
and V6, finally opening tap B slowly in order to regulate the flow.
To fully evacuate the system and Vessel 1, the sample liquid must be frozen by
raising a dewar of liquid nitrogen around it. When the sample is frozen, a vacuum can
be achieved by switching the pump to its roughing mode and opening valve V1. For a
high vacuum, switch the pump to turbo.
2.2.2 Removing air from Vessel 2
Once the system has been pressurised, tap E on Vessel 2 can be opened. It is possible
to bubbled helium gas through the sample liquid against the non-return valve, V13. If
this is required, first ensure that valves V5, V6 and V8 are closed. Valve V10 can
now be opened and slowly opening V7 allows the gas flow to be regulated.
To fully evacuate the system and Vessel 2, the sample liquid must be frozen by
raising a dewar of liquid nitrogen around it. When the sample is frozen, a vacuum can
be achieved by switching the pump to its roughing mode and opening valve V1. For a
high vacuum, switch the pump to turbo.
2.2.3 Removing air from Vessel 3
Once the system has been pressurised, tap C on Vessel 3 can be opened. It is possible
to bubbled helium gas through the sample liquid against the non-return valve, V13. If
this is required, first ensure that valves V5, V6 and V7 are closed. Valves V10 and
V8 can now be opened and slowly opening tap D allows the gas flow to be regulated.
To fully evacuate the system and Vessel 3, the sample liquid must be frozen by
raising a dewar of liquid nitrogen around it. When the sample is frozen, a vacuum can
be achieved by switching the pump to its roughing mode and opening valve V1. For a
high vacuum, switch the pump to turbo.
2.2.4 Evacuation of the sample cell
Once the system has been purged of oxygen, the sample cell can be evacuated. To do
this, ensure that all the taps on the sample vessels are closed and the pump is switched
to its roughing mode. Open valves V1, V2 and V3 to evacuate the system. Opening
valve V4 will evacuate the sample cell. Switch the pump to turbo mode and leave to
pump for as long as possible. When the sample cell is sufficiently clean, close valves
V1 and V4 and let the system up to atmosphere using helium.
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