Method for leak testing and leak testing apparatus
OwnerMartin Lehmanninventor
Life of this patent
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Abstract
For leak testing closed containers (9) which are filled with a filling product containing at least one liquid component the container is introduced in a test cavity (1) which is evacuated at least down to vapour pressure of that liquid component. The pressure in the surrounding of the container (9) and thus within test cavity (1) is monitored. Monitoring is performed by a vacuum pressure sensor (7), whereas lowering pressure surrounding the container (9) is performed by a vacuum pump (5). Leakage is detected by monitoring a pressure change in the surrounding of the container which is due to evaporation of liquid emerging from a leak and being evaporated in the low pressure surrounding.
Claims47
A method for producing a closed and filled container comprising:
- filling a container with a material comprising at least one liquid component;
- sealingly closing the container;
- and
- leak testing the container, wherein the leak testing includes
- applying a pressure difference across at least a part of a wall of the container, which part is to be leak tested, by evacuating the surrounding of the container to a pressure value at least according to vapor pressure of the at least one liquid component;
- monitoring the pressure in the surrounding as a leak indicative signal;
- comparing a signal derived from the pressure monitored with a dynamic threshold value for identifying leak condition of the container and enabling a further signal derived from the pressure monitored to be averaged with similar further signals of other containers previously tested as unleaky if the identifying of the container now under test reveals an unleaky container and further deriving the threshold value from the result of the averaging.
Dependencies are inferred from the claim text.