INFICON T-Guard Leak Detection Sensor - Manual (Page 66)

64
Operation
jina
85
e 5
.fm
Tech
ni
ca
l Ha
nd
bo
ok
(1
11
2)
A7: Measurements are less reproducible if you do not use the green measuring
hoses from INFICON. Hoses with an inside diameter of more than 1 mm cannot
be used.
A8: Measurements are less reproducible if the green hoses have not been inserted
completely into the couplings.
Apply a very thin grease film to the ends of the hoses in order to be able to insert
them completely. You notice this by the hose sliding into the coupling a second
time.
Q: Why does the measured leak rate get smaller and smaller when I do not
purge the chamber in between measurements?
A: Check the chamber for thin slots and small holes. Helium may escape there. This
leads to smaller leakage rates over time.
Remedial measures: Seal your chamber. Use the rubber gaskets for the
chamber lid.
Q: Why does the calibration not work?
A1: Enter the correct chamber volume and adjust the trigger level and the test
leakage rate to the used leakage rate.
If you use diluted helium, you must enter this in the device.
A2: Check all answers to the first question: "Why can the measurements not be
reproduced?"
Q: Why do I receive a warning after confirming the new calibration factor?
A: Your measurement set-up can and should be improved.
Remedial measures: Check the chamber volume, the chamber for slots and
holes, as well as the test leakage rate, the trigger level, the measuring time and
the fan.
Q: Why does the measured leakage rate increase over time?
A1: If the T-Guard has not been used for a long time, the sensor drifts a little
downwards. This drift becomes increasingly smaller, so that the measured
leakage rate may rise a little. The measurement should be stable after two hours.
A2: The test leak could take some time to stabilise.
Remedial measures: Use leaks from INFICON.
A3: The helium and air mixture takes a long time in your test sample.
Remedial measures: Evacuate the test sample as far as possible before filling it
with helium.