Cool-down problems
CryoProbe Installation BRUKER 65 (93)
Reduce pressure at He Compressor
The He pressure in operation is regulated by the CryoCooling unit in full automa-
tion and no adjustment should be necessary.
To reduce the He pressure at the He Compressor before starting, see its opera-
tion manual which is delivered with the CryoPlatform.
Periodic hiss is missing 5.3.4
Symptom:
Cool-down is started, the He Compressor runs but the characteristic
periodic sound from the CryoCooling Unit is missing.
Possible cause:
The plate inside the ColdHead is either in the wrong position or it
is blocked. This may happen, when the pressure on the Return is higher than on
the Supply due to interchanging the order of connecting the two Flexlines.
Corrective action:
A higher pressure has to be built up on the supply line of the
ColdHead. Drive at the He Compressor front must be Off.
step action
1.1 Disconnect the S
UPPLY and then the RETURN Flexline from the Cryo-
Cooling Unit.
1.2 Close all valves. (Notice that V4 and V8 are normally open!)
1.3 Open V7 and V8 to relief the pressure of the R
ETURN.
1.4 Close V7 and V8
1.5 Adjust now the pressure of the He gas supply with the pressure regula-
tor to 17 bar. If the pressure is too high open V5 and V9 and relieve it by
opening V8 for a short time.
1.6 Close all valves
1.7 Now switch O
N the DRIVE of the ColdHead (which is located on the
back side of the He compressor) and open V7 and V8. Then open and
close V6 several times for a few seconds. With this action the pressure
on the S
UPPLY will be higher than the pressure of the RETURN.
1.8 Repeat the last step up to five times. As soon as the characteristic hiss
sound is heard, switch O
FF the DRIVE of the ColdHead and close all
valves and re-establish the original configuration.
If the periodic hiss cannot be heard, the valve might be blocked and
needs to be handled as described in the next steps.
1.9 Close all valves (V4 and V8 are normally open!).
Connect the large DumpTool to the S
UPPLY of the ColdHead.
Open its relief valve compleatly!
1.10 Open V5, V7 and V9
1.11 Switch on the O
N the DRIVE of the ColdHead (which is located on the
back side of the He compressor)
To Next Page
Loading...
Need help?
General
