INFICON
Installation | 5
T-Guard2_Operating-instructions-jina85en1-13-(2009)
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The measuring line and reference line must be the same length.
• Measuring chamber
The net volume, i.e. the measurement chamber volume minus the volume of the
test object, must be between 0.01 and 10,000 liters. The measurement chamber
should not be bigger than necessary, but the test object may not touch the walls.
Apart from the outside air inlet, the measurement chamber must be leak-proof.
• Fan
The measurement chamber must have at least one fan that blows air at the test
object. If the test object has a leak, the helium that emerges is distributed equally
around the test chamber. It is therefore irrelevant from the point of view of the
measurement result whether the leak is close to the measuring line.
• Test object
The test object should not be placed on the areas that may be leaking.
• Outside air inlet
The inlet for the outside air must be opposite the exhaust air connection. Do not
make the outside air inlet too big. Helium may not escape from the measurement
chamber at this point.
• Reference line
For the best possible reproducible results, supply outside air to the reference
inlets. The same air must be sucked in by the reference line as in the
measurement chamber.
• Fore pump
All vacuum pumps with a gas flow of more than 200 sccm at a basic pressure of
under 50 mbar can be used as a fore pump. INFICON offers a suitable pump as
an accessory.
