Dust protected leak testing device inlet valve - contains suction tube with constriction and porous ceramic stopper bead

摘要

A leak testing device valve head with a test gas suction tube is designed to avoid loss of operation due to the ingestion of dust and resultant clogging. It is a thin, robust and reliable valve assembly. The inlet opening of the suction tube is covered with a porous ceramic material in bead form. The suction tube (5), pref. of high-grade steel, has a restriction (10) near the inlet forming a flow impedance behind which a low pressure suitable for mass spectrometer operation is formed. The suction tube and porous bead are mounted inside a further tube.