CHAPTER 1 - DESCRIPTION
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1.2 HELITEST DESCRIPTION
The HeliTest set is available in five configurations.
Model 969-3510, consisting of:
•
1 HeliTest basic unit;
•
1 Battery;
•
2 Straps;
•
2 Spare main fuses 1.6 A.
Model 969-3570, consisting of:
•
1 HeliTest basic unit;
•
2 Batteries;
•
2 Straps;
•
1 Ac/Dc converter-battery charger, 100-240 Vac
input (50/60 Hz);
•
1 Power cable (battery to HeliTest);
•
1 Car battery cable;
•
1 Extension probe stick;
•
2 Spare main fuse 1.6 A;
•
1 Travelling case.
Model 969-3575, consisting of:
•
1 HeliTest basic unit;
•
1 Ac/Dc converter battery charger, 100-240 Vac
input (50/60 Hz);
•
2 Spare main fuse 1.6 A.
1.2.1 Theory of operation
The piece to be tested is filled with a helium/air mixture.
The probe is passed over the suspected area, and a
gas sample is continuously sucked through the flexible
extension by the sampling line.
The pump blows the gas sample over a special heated
silica capillary which stops atmospheric gases but
allows Helium to pass through due to its small
molecule. The atmospheric gas is exhausted at the top
of the sensor, while Helium molecules reach the
pressure detector. The electric signal related to Helium
pressure is processed by a dedicated software and
hardware combination allowing a direct read-out of
Helium concentration on the display (refer to fig. 1-2).
Figure 1-2 - Operating principle