Cold operation problems
CryoProbe User Manual BRUKER 81 (107)
VT gas interrupt 7.6.8
CAUTION: Never allow the VT gas to be interrupted or switched O
FF while the
CryoProbe is cold! If a VT gas interrupt occurs: eject the sample immediately!
A VT gas interrupt may not be evident until an ‘overheat’ error of the VT heater oc-
curs or the lock drops - which can be too late for sample solvents with a high melt-
ing point like water or benzene. Even if an automatic ‘emergency warm-up’ of the
CryoProbe System were initiated, it would be too slow to prevent these samples
from freezing.
Cooling water leakage 7.6.9
This section applies only if a water-cooled He Compressor is used.
If a closed-cycle water chiller is used: determine the cause of leakage before refill-
ing the chiller.
If a water leak cannot be sealed during operation, the CryoProbe must be warmed
up.
If the cooling water supply is interrupted or drops such that the heat cannot be
removed anymore, the He Compressor and the CryoCooling Unit will stop after a
while and perform a passive emergency warm-up. Upon return of the cooling wa-
ter, press
COOL DOWN to continue cold operation or WARM UP to terminate.
He leakage 7.6.10
WARNING: A leak in a pressurized gas system indicates a potential hazard. Be-
fore you do anything to fix the problem: Put on protective glasses and gloves! See
also "Pressurized cold helium gas cycle" on page 9
.
If a He loss exceeds the equivalent of about one recharge/week, the CryoControl-
ler will stop the system automatically.
He steel-cylinder empty 7.6.11
CAUTION: The He steel-cylinder cannot be exchanged while the CryoProbe is in
cold operation because the He system would be inevitably contaminated by air.
For the same reason, do not try to recharge He at the He Compressor back while
the system is in cold operation.
Warm-up the CryoProbe and proceed according to "NOTE: The ‘Elapsed Time’
and the ‘Main pressure’ as of Table 6.2. cannot be recorded in the automatic
logfile. Thus, your log-book and the logfile will contain important comple-
mentary information." on page 66.
Pneumatic gas pressure too low 7.6.12
If the pneumatic gas pressure drops to below the minimum specified value, the
correct operation of the valves is no longer assured. If an undefined valve config-
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