| 摘要 |
Many hollow bodies such as cast parts, etc., have to be tested for impermeability in industry. The differential pressure method with compressed air is mainly used for this. Parts which are not sealed are assorted, again placed under pressure and are dipped into a bath in order to localise the leaks. If a fluorinated hydrocarbon gas, as used in refrigeration technology, is used instead of compressed air, leaks can be detected both by pressure drop and also externally by means of an electrical sensor. This sensor acts in connection with a microprocessor, on which the leakage rate can be preset. In this manner the leaks can be detected in mass production without interruption of the testing process. The special feature of the impermeability test device is that the fluorinated hydrocarbon gas is sucked out of the hollow body after the test process, compressed in a compressor and then liquefied in a condenser. The liquid refrigerant can then be again supplied in gas form via an evaporator to the new hollow body to be tested. Various possibilities exist for the embodiment of the evaporator and compressor, and are described in more detail in the patent application. In this manner, no fluorinated hydrocarbon gas reaches the atmosphere, with the exception of traces which emerge from the leaking point on the parts. These small quantities are out of the testing region ... Original abstract incomplete.
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