6 | Operation
INFICON
48 / 90
T-Guard2_Operating-instructions-jina85en1-13-(2009)
1
Helium concentration
7
Accumulation time
2
Start
8
Second GROSS measurement
3
Helium in environment
9
Second FINE measurement
4
Time
10
Waiting time before purge
5
First GROSS measurement
11
Purge time
6
First FINE measurement
12
Measuring time
GROSS measurement
and FINE
measurement
During the measurement, the switch between GROSS and FINE measurement takes
place automatically. For the GROSS measurement, the sensitivity is limited to protect
the sensor from helium contamination. The sensor measures with the highest
sensitivity for the FINE measurement.
Measurement cycle
The accumulation measurement begins with a GROSS measurement. If, at the
beginning of the measurement, the helium concentration in the measurement chamber
is already higher than the environment by approx. 1000 ppm, the test object has a
large leak. In such a case, the device stops the measurement. The display shows a
leak rate that is a hundred times higher than trigger value 1, or, if used, trigger value 2.
If the test object passes the GROSS measurement, the device switches to FINE
measurement.
The device stops if the helium concentration increases too quickly during the FINE
measurement. The display shows a leak rate that is 5 times higher than trigger value
1, or, if used, trigger value 2.
After the first FINE measurement, a short measurement break follows, in which the
test object can be subjected to higher pressure. Then the second GROSS
measurement takes place. The second GROSS measurement is necessary because a
large leak could have occurred as a result of the additional pressure.
Содержание 540-200
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