Leybold Vakuum Gmbh

Markus Nothhelfer

Rudolf Flosbach

Ingo Seckel

Joachim Klein

A process is disclosed for testing the tightness of a package ( ) containing a packaged object ( ) and in which a test gas is contained; leak testing is performed in such a manner that the packaged object ( ) is introduced into a test chamber formed by two extensible foils ( ) and where the space between the foils ( ), in which the packaged object is contained, is evacuated in such a manner that the foils ( ) can wrap the packaged object ( ); at least in the areas of their surfaces which face the packaged object ( ) and in which the tightness of the package ( ) is to be inspected, the foils ( ) are provided with means ( ) which form a coherent intermediate space ( ) over the areas to be inspected of the package ( ); the intermediate space ( ) is evacuated down to a pressure lower than the pressure within the package ( ); the evacuated intermediate space ( ) is connected to a detector ( ) sensitive to the test gas to determine if test gas escapes outwards through the inspected area of the package ( ).

Process for testing the tightness of packages

A helium supply unit (1) supplies helium from a high pressure storage (21) to fill a test chamber (6) which encloses a sample holder (5) to be examined for leaks by measuring device (2) including a mass spectrometer (3) and a control unit (4). The test gas is recovered after the testing by a pressure difference between a low pressure storage (18) and the test chamber (6). The test chamber is evacuated prior to receipt of the test gas by a vacuum pump (27) and after testing by a vacuum pump (34) for more complete helium recovery. The recovered test gas is then transmitted back to the high pressure storage (21) through a compressor (19), which raises the pressure of the recovered gas to a predetermined pressure, from the low pressure storage (18). The control unit (4) also controls a pure test gas supply (37) and a release valve (44). The concentration of the recovered test gas is measured and, if the concentration is too low, the control unit (4) releases the recovered test gas through valve (44) and admits fresh test gas from the supply (37) into the helium supply unit (1) at a point between the low pressure storage (18) and the compressor (19). In this manner, expensive test gases, such as helium, are recovered and reused.

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Kerpen, Germany

Markus Nothhelfer