D135-10-880C - Description
Page 7
Besides maintaining the pressure in the mass spectrometer the pump system is used to
evacuate the test parts. It is made sure that the pressure in the mass spectrometer is low
enough under all circumstances. The valves V1, V2a, V2b, V4a control the gas flows when
measuring. Valves V3 and V5 are used to vent the system and the Turbo pump, valve V6
controls the gas ballast function of the fore vacuum pump. Valve V7 opens and closes the
internal test leak during calibration.
With the pressure in the test part being lower than ambient pressure sprayed helium (or
Hydrogen as forming gas) can penetrate into the part in case of a leakage. As soon as the
pressure conditions allow it one of the valves to the TMP opens. Now Helium can penetrate
into the mass spectrometer contrary to the pumping direction of the TMP.
To Next Page
Loading...
