Abstract: An apparatus to test integrity of a seal of a package. The apparatus includes a height detector detecting a height of the package, a test portion determining the integrity of the seal based upon a position of the test portion as a function of time when contacting the package, and a mover moving the test portion into an initial position of contact with the package based upon the detected height. The test portion includes a test head contacting the package, and the mover includes a servo motor driving the test head, and a ball screw linking the servo motor and the test head.

Abstract: Apparatus and methods for in-line testing of the internal pressure of flexible containers traveling along a production line at high speeds. The apparatus inspects semi-rigid plastic and thin-walled liquid filled containers by analyzing the output from a load cell that indirectly measures the reaction force applied to a container through the intermediary of a load cell roller that, in turn, supports a flexible belt that directly contacts containers while moving them through an inspection station without interrupting the flow of the production line. Containers are contacted only by a flexible portion of a conveyor belt to minimize structural and aesthetic damage to them that might otherwise occur during the inspection process.

Abstract: A containment enclosure system at least a portion of which is double-walled. An exemplary system of the invention provides enhanced leak protection by monitoring the space within the double-walled portion of the containment enclosure system. The system is capable of providing continuous monitoring of the enclosure, collar, penetrations, and/or joints for potential leaks. Containment enclosures of the invention may be used as, used with, or attached to tanks, piping, dispensers, or any other type of storage container including vessels, boxes, spheres or containers of any shape. These containment enclosures may be underground, partially underground, or aboveground. In addition, these containment enclosures may be completely enclosed or enclosed on the bottom and sides with an open or covered top.

Abstract: Systems and methods for detecting and locating leaks in internal pressure vessels. A method generally includes forming a pressurizing cavity external to and adjacent an internal pressure vessel. A pressurized fluid is injected into the pressurizing cavity to cause pressurized fluid to flow from the pressurizing cavity through a leak into the internal pressure vessel. The internal pressure vessel is monitored to detect leakage of pressurized fluid into the internal pressure vessel.

Abstract: The invention relates to a method and device for the determination of the gas permeability of a container, for example, a PET bottle. Said container is enclosed by a sheath, which hermetically seals the container from the environment. The intermediate space, between the container and the sheath, has only a very small volume in comparison to the volume of the container. The determination of the gas permeability is begun by bringing said intermediate space to, for example, atmospheric pressure, whilst the container is filled with a test gas by means of a special feed, until the container is at an overpressure relative to the intermediate space. The pressure in the intermediate space increases by means of the resulting diffusion of the test gas through the wall of the container into said intermediate space. The increase in pressure per unit time is a measure of the permeability of the container.

Abstract: A closure assembly is described which includes a plurality of inflatable seals, a sliding door, and a frame configured to allow said door to slide back and forth therein. The sliding door includes a first portion having an opening therethrough and a second solid portion. The door further include a plurality of grooves, one plurality encircling the opening in the first portion and second plurality encircling the second portion. The inflatable seals are configured to fit into at least one of the grooves encircling each portion. The frame has a middle opening which can be aligned with the first portion of the door for allowing objects to pass through. The frame also has a top opening and a bottom opening which allows changing of the inflatable seals without removing the door from the frame. The assembly provides for a sealing of either portion of the door around the middle opening of the frame.

Abstract: A liquid storage tank and a method of fabricating and testing the liquid storage tank. The tank is collapsible for ease of transportation when not holding a liquid and includes a base portion and a top portion. The base portion has a bottom wall and a frusto-conical sidewall that is sealed to the bottom wall. The top portion is sealed to the sidewall, and has a flexible opening. The opening is linear in the preferred embodiment and is openable to draw liquid from the tank and closable to prevent contaminants from entering the tank. The bottom wall is substantially circular and the top portion includes two substantially semi-circular sections joined and overlapped along the straight edges to form an overlapped region. The sidewall includes generally triangular-shaped sections, and the sections are joined to one another with seams that extend in a slightly helical fashion about the tank. The opening includes a slit in the overlapped region and two L-shaped members.

Abstract: A system and method for leak testing a plurality of hermetic electronic packages of the type that have an internal chamber that is isolated from ambient conditions by a seal structure is advantageously designed to be able to calculate the leak rate of each individual device in a manner that is independent of structural manufacturing variances that typically exist within a sampling of such devices. The method preferably involves positioning a plurality of the hermetic electronic packages within a test area, and then stimulating the hermetic electronic packages with a modulated input of energy, such as by varying the ambient pressure about the devices. A property such as the physical position of one portion of a lid of each of the hermetic electronic packages is then sensed. The sensed property is one that is known to change as a first function of the modulated input of energy and also as a second function of pressure conditions within the hermetically sealed internal chamber.

Abstract: Leak testing a closed container with at least one flexible wall area is performed with the method and apparatus wherein a biasing arrangement compresses or expands the container under test. A biasing force is monitored with a force detector applicable to the wall of the container. The force detector generates an electric output first biasing force signal at a first po9int in time which is stored for comparison with the monitored biasing force signal at a second subsequent point in time to generate a different signal as a leak indicative signal. A difference signal is generated at the first point in time from the first force measuring signal stored and the first force measuring signal. This latter difference signal is stored as a zero offset signal which is used to compensate zero offset of the generated difference signal.

Abstract: The present invention provides an apparatus and method for evaluating the integrity of a seal on liquid-filled container. According to one aspect of the invention, the apparatus comprises a tank for containing a liquid solution and a clamp with a first and second member between which the container is engaged. The clamp is positioned with respect to the tank such that a portion of the container properly situated in the clamp will extend into the tank and contact the liquid solution. A ram and cylinder are operatively connected to the clamp to engage the container. A seat is provided to support a portion of the container such that at least a portion of the container supported by the seat will extend into the tank. A drill is provided to pierce a surface of the container to make an opening. The drill is positioned such that the opening can be made while the container is in the clamp and/or the seat such that at least a portion of the container extends into the tank.

Abstract: The invention relates to a method for performing a leak test on a gas generator (1), especially for airbags, according to which: the gas generator (1) is filled with a pressurized gas mixture, among other things, helium; the gas generator (1) filled with the gas mixture is introduced into a test chamber (2); gas is evacuated from the test chamber (2); the amount of helium exiting from a possibly present leak is determined with the aid of a sensor, and; the signal furnished by the sensor is used for determining the tightness/leakage of the gas generator (1). In order to accomplish the goal of performing a cost-effective search for leaks, the invention provides that the gas generator (1) is filled with a gas mixture whose helium proportion is equal to at least 50%.

Abstract: Apparatus and methods for in-line testing of the internal pressure of flexible containers traveling along a production line at high speeds. The apparatus inspects semi-rigid plastic and thin-walled liquid filled containers by analyzing the output from a load cell that indirectly measures the reaction force applied to a container through the intermediary of a load cell roller that, in turn, supports a flexible belt that directly contacts containers while moving them through an inspection station without interrupting the flow of the production line. Containers are contacted only by a flexible portion of a conveyor belt to minimize structural and aesthetic damage to them that might otherwise occur during the inspection process.

Abstract: A method for testing a vacuum package with regard to seal-tightness, the vacuum package is placed with at least one surface section against at least one contact surface of a vacuum device. A vacuum is generated on a side of the contact surface opposite the vacuum package. A parameter indicative of an air flow through the contact surface in a flow direction away from the vacuum package is measured. The parameter is compared with at least one limit value. A first state is assigned to the vacuum package when the parameter surpasses the at least one limit value and a second state is assigned to the vacuum packaged when the parameter drops below the at least one limit value.

Abstract: The present invention relates to a method and assembly for leak detection in a plasma system. The invention can accomplish not only leak detection, but also leak location while maintaining a plasma within the plasma system. Leak detection for the invention is achieved by obtaining spectral data of the plasma at one or more times while maintaining the plasma within the plasma system and comparing the same to predetermined spectral data of air. Upon a determination that air is present within the plasma system, one or more external surfaces of the plasma system are exposed to a test gas and the spectral data of the plasma is analyzed after each exposure to determine if the test gas is present in the system. If the test gas is present, a determination can be made that the particular external surface to which the test gas was applied is a leak location.

Abstract: A malfunction detection device of a bellows type accumulator for pressurized fluid includes malfunction judgment unit for judging a malfunction of the bellows type accumulator on the basis of a detection output of the pressure sensor. The malfunction judgement unit judges that the malfunction of the seal member generates when the difference between a peak pressure value appeared before a predetermined time is past after the starting of the pressure increase from a value below a predetermined value in the inlet and outlet port and a stable fluid pressure appeared after the appearance of the peak pressure value is not within a predetermined range and/or when the peak pressure value does not appear before the progress of the predetermined time.

Abstract: A system for testing systems which are in turn used to test the leaktightness of a hollow body is suggested.

Abstract: A method and apparatus for determining the hermeticity of a semiconductor package is disclosed. Gas is introduced into the semiconductor package during packaging. Vacuum suction is then applied to the package. If the package has any leaks, the gas within will escape. The package is next scanned using a spectrometer. If the spectrometer does not detect any gas within the package cavity, the package is not hermetically sealed. In an alternate embodiment, the device is packaged first, and then immersed in a pressurized liquid. If the package has a leak, the pressure on the liquid will force liquid into the package cavity. The cavity of a properly sealed package will remain empty and dry. The package is scanned using a spectrometer. If the spectrometer detects liquid within the package, the package is not hermetically sealed.

Abstract: A method and apparatus for determining the hermeticity of a semiconductor package is disclosed. Gas is introduced into the semiconductor package during packaging. Vacuum suction is then applied to the package. If the package has any leaks, the gas within will escape. The package is next scanned using a spectrometer. If the spectrometer does not detect any gas within the package cavity, the package is not hermetically sealed. In an alternate embodiment, the device is packaged first, and then immersed in a pressurized liquid. If the package has a leak, the pressure on the liquid will force liquid into the package cavity. The cavity of a properly sealed package will remain empty and dry. The package is scanned using a spectrometer. If the spectrometer detects liquid within the package, the package is not hermetically sealed.

Abstract: The claims are drawn to a method of detecting seal breakage or incomplete seal formation in a package, said method comprising the steps of: (i) providing said package, prior to sealing, with a strip or ring of an indicator comprising an oxygen scavenging composition which includes a source of labile hydrogen or electrons and at least one reducible organic compound, wherein said strip or ring is located on an internal surface adjacent to where a seal is to be formed, (ii) treating the strip or ring with electromagnetic energy so as to reduce the reducible organic compound to a reduced form which is oxidizable by ground state molecular oxygen regardless of the presence of a transition metal catalyst and such that, when oxidized, there is a detectable change in a characteristic of said composition selected from the group consisting of: colour, fluorescence emission and UV-visible, infrared or near-infrared absorption, (iii) subjecting said package to a sealing process intended to seal the package, and (iv) detec

Abstract: The loss of trace gas to the atmosphere when leak testing heat exchangers is avoided by the use of internal and external containers, with both the trace gas sensor and the coil to be tested being placed within the internal container. The space between the two containers is preferably placed under a vacuum, and the inner and outer containers are fluidly connected to a refrigerant recovery vessel for the accumulation of leaked trace gas. The trace gas can then be returned to the charging system for reuse. The use of extractors can also be made to conduct the flow of leaked trace gas from the containers to the refrigerant recovery vessel. A containment that is also provides to receive and contain any contaminated refrigerant from the two containers.

Abstract: A method and device for testing containers, the method calling for a difference in pressure to be generated between the pressure inside the container and the pressure immediately surrounding the container, the behavior of one of these pressures permitting the gas tightness of the container to be assessed. A pressure value is stored and subsequently compared with one of the pressures, the stored pressure value being stored electronically and compared with at least one value of the output signal from a pressure sensor. The container is housed in an enclosure which is connected to a pressure or suction line, and a pressure-value storage unit, a comparator unit and a pressure sensor are associated with the pressure or suction line.

Abstract: The present invention relates to a method and system for detecting air leaks in tires and in a tire testing machine. Each of the tires is mounted on the tire testing machine; inflated with an air flow from an inflation system to a first pressure; and maintained at the first pressure by continued supply of air from the inflation system into the tire. The flow of the continued supply of air is measured with a calorimetric flow sensor calibrated to output a sensor signal having a full scale value corresponding to an identical model tire mounted on the tire testing machine with no air leaks in the model tire or the testing machine. The flow of the continued supply of air is compared with an averaged flow for previously measured tires mounted on the tire testing machine with no air leaks in the tires or the testing machine. A control signal indicating an air leak is outputted if the sensor signal is 20% to 80% of the full scale value.

Abstract: A portable containment system includes a glovebox apparatus, a self-contained filter unit, and removable conduits extending therebetween. The glovebox apparatus includes a first module for releasably covering a first sidewall opening. The first module, which has body and flange portions, has a storage position where the body portion is positioned through the first sidewall opening into the glovebox interior and an operative position where the body portion is positioned exterior of the glovebox. The glovebox apparatus includes second modules for releasably covering a second sidewall opening where the second modules are smaller than the first sidewall opening for inserting the second modules into the interior of the glovebox for storage. The filter unit includes a plurality of gas filters, an air pump, and detectors for monitoring the air flow through the system.

Abstract: A conveyor assembly 18 that detects bags that leak. The assembly 18 includes a first conveyor 24 that operates in unison with a second conveyor 29. The conveyors 24 and 29 confine the bags in chambers, with the bags being engaged by pressure assemblies 50 so that the bags that leak are reduced in volume. The bags are engaged at a downstream position and at an upstream position by detection devices 44 that provide a signal indicative of the volume of each bag. These signals are compared to thereby identify bags that leak.

Abstract: A leakage inspection method for a sealed container in which a liquid of a non-electrolyte is contained for judging whether a defect exists in the container, the method comprising the steps of applying an inspection AC voltage through electrodes from an inspection power source unit; detecting an AC current flowing through the container and the contained liquid by means of a current detector; obtaining a digital value corresponding to an absolute value of the instantaneous value of the detected AC current; successively totaling the digital values during a totaling period having a specific relation to the waveform of the AC current whereby the total value of the digital values corresponding to the absolute values of the respective instantaneous values of the AC current is arithmetically operated and judging that the defect exists in the container when the total value as the value to be judged is larger than a setting value.

Abstract: The object of this invention is to provide a leakage-detecting device for sealed packages that is capable of performing detection continuously for all sealed packages when performing leakage detection for sealed packages.

Abstract: 1. Method for testing the tightness of capacitive sensors 2.1. Known methods of seal testing cannot be used because of the extremely small volume of the sensor cavity or on wafer level. Other known methods of seal testing are only possible with high expenditure on safety because, for example, radio isotopes are used. 2.2. Method for testing the tightness of capacitive sensors arranged in a hermetically sealed enclosure, in which the processed sensors are arranged in the form of a wafer, wherein the already sawn wafer bearing the sensors is immersed in a test fluid under defined conditions, the capacitance of each sensor is then measured and compared with the capacitance of reference sensors. 2.3. The invention is especially suitable for testing the tightness of capacitive, hermetically sealed sensors.

Abstract: A system for testing systems which are in turn used to test the leaktightness of a hollow body is suggested.

Abstract: A sealed package's transmission of oxygen, water vapor, carbon dioxide, or other gas or vapor that is of interest because of its potential adverse effects on the package contents is determined indirectly, based upon the package's transmission of a different gas selected as a test gas. Helium is preferred as a test gas. The package's total transmission of the test gas is separated into its components of leakage through the package seals and permeation through the packaging material itself. The package's leakage of the gas of interest is determined based on its leakage of the test gas, in accordance with the molecular weights of the gases.

Abstract: In a method for testing a vacuum package with regard to seal-tightness, the vacuum package is placed with at least one surface section against at least one contact surface of a vacuum device. A vacuum is generated on a side of the contact surface opposite the vacuum package. A parameter indicative of an air flow through the contact surface in a flow direction away from the vacuum package is measured. The parameter is compared with at least one limit value. A first state is assigned to the vacuum package when the parameter surpasses the at least one limit value and a second state is assigned to the vacuum packaged when the parameter drops below the at least one limit value.

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.

Abstract: The invention provides an efficient inspection method for inspecting a hermetically sealed package for pinholes, in which when a hermetically sealed package whose contents such as electrically conductive fluid or food are covered with an electrically insulating film is inspected for pinholes by using a high voltage, the inspection can be achieved with an extremely simple procedure while fully preventing occurrence of misoperations due to the atmosphere such as humidity during the inspection. In a hermetically sealed package in which contents 1 such as electrically conductive fluid are covered with an electrically insulating film 2, an electrical conductor 4 derived from a voltage output terminal of a DC high voltage power supply 6 is put into contact with or proximity to a side face portion 31 of the hermetically sealed package, by which the contents 1 in the hermetically sealed package 3 are electrified.

Abstract: The invention relates to a method for the integral leak detection on test samples with relatively thin walls, in which the test sample (1) comprising the test gas is tested for leaks in a test chamber; in order to test whether or not test samples are properly filled with test gas, it is proposed that for checking the test gas concentration in the test samples (1), the test gas concentration in at least one of the test samples (1) is measured thereby that its wall (2) is provided with a leak (4), and that with this test sample (1) a leak detection process is carried out.

Abstract: Leak testing a closed container with at least one flexible wall area is performed with the method and apparatus wherein a biasing arrangement compresses or expands the container under test. A biasing force is monitored with a force detector applicable to the wall of the container. The force detector generates an electric output first biasing force signal at a first po9int in time which is stored for comparison with the monitored biasing force signal at a second subsequent point in time to generate a different signal as a leak indicative signal. A difference signal is generated at the first point in time from the first force measuring signal stored and the first force measuring signal. This latter difference signal is stored as a zero offset signal which is used to compensate zero offset of the generated difference signal.

Abstract: The invention is relative to a leaktight chamber (3) in which a liquid having electrical characteristics, preferably a conductive liquid, is introduced into a leaktight volume (33) between the cover (5) and the tank (4), and in that a value of electric quantities is measured which varies with the reduction of the liquid contained in the volume (33). In such a way the leaktightness is continually checked.

Abstract: A method for operating a film leak detector (1) which includes two films (5, 6) each stretched in a frame (3, 4), which, with a test sample (79) emplaced, delimit a test chamber (80). The detector is equipped with two vacuum pumps (13, 30), in which first the test chamber (80) is evacuated and, after the evacuation operation, a leak detection operation takes place. In order to avoid test gas pollution and impurities during the first phase of the evacuation of the test chamber (80), only one (13) of the two vacuum pumps is operated and during the leak detection operation only the second vacuum pump (30) is operated.

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.

Abstract: A machine 10 to test bags 11 to detect faulty bags 11a. The machine 10 includes a probe assembly 23 including a belt 27 which supports a plurality of probes 31. More particularly the bags 11 are engaged by probe portions 33, with displacement of the probe portions 33 providing data for a CPU controller 24 enabling the detection of faulty bags 11a. Faulty bags 11a are then ejected from the conveyor 13 by bag ejector 21.

Abstract: An apparatus for testing a waterproof state of a sub insertion portion of a grommet provided in eccentric with a main insertion portion. The apparatus is provided with an enclosure for sealably enclosing an end portion of the sub insertion portion, an air feeder for feeding air for testing to a space in which the sub insertion portion is sealably accommodated, and a judging apparatus for judging whether the sub insertion portion is in a good waterproof state based on a status of the air fed from the air feeder.

Abstract: Leak testing a closed container with at least one flexible wall area is performed with the method and apparatus wherein a biasing arrangement compresses or expands the container under test. A biasing force is monitored with a force detector applicable to the wall of the container. The force detector generates an electric output first biasing force signal at a first point in time which is stored for comparison with the monitored biasing force signal at a second subsequent point in time to generate a different signal as a leak indicative signal. A difference signal is generated at the first point in time from the first force measuring signal stored and the first force measuring signal. This latter difference signal is stored as a zero offset signal which is used to compensate zero offset of the generated difference signal.

Abstract: The invention relates to a test gas leakage detection apparatus (1) comprising a test chamber (2) and supply and measuring devices such as fore-pumps and high-vacuum pumps, test gas detectors, electronic components, etc. In order to construct an apparatus of this type in a manner which is simple and which does not restrict mobility, the invention provides that the test chamber (2) and the supply and measuring devices are combined to form a modular unit, and that the test chamber (2) is supported on a housing (3) in which the supply and measuring devices are accommodated. In addition, air cooling devices are assigned to thermally critical components of the supply and measuring devices.

Abstract: An improved method for detecting leaks in a sealed package or container, where the contents of the container includes at least one liquid component, is disclosed. First the container to be tested is placed in a vacuum chamber which is in turn sealed. A vacuum is then applied to the vacuum chamber to lower the pressure, within the chamber, to a pressure that is below the vapor pressure of the liquid component in the container being tested. The vacuum source is then isolated from the chamber. The presence and severity of any package leak is detected by monitoring the increase of pressure in the vacuum chamber as a leak indicative signal whereby a relatively steady increase in pressure over time is indicative of “leaking” unrelated to the package under test and wherein relatively uneven increases of pressure, over time ,is indicative of boiling liquid and therefore a leak in at least one test specimen.

Abstract: A laser displacement transducer mounted on an X-Y table below a vacuum chamber with a bottom glass window measures displacement in flexible surfaces of sealed packages to test for leakage. Sealed packages, including multi-chamber packages are positioned precisely in a grid pattern by rapid loading and unloading of the top of the vacuum chamber mounted on top of a console to permit using the device with an assembly line. Leaking cavities and packages are instantaneously identified by comparison of the measured displacement with programmed information about displacement and the results displayed on a screen. Leaking packages are discarded and well sealed packages are returned to the assembly line.

Abstract: A method and apparatus for testing seals of packages or containers incorporating gas permeable materials wherein the packages are placed between opposing components of a vacuum test chamber such that the seals of the packages are open to a pressure testing system. A flexible bladder backed by a foam material or pressurized fluid seal the gas permeable material afterwhich at least a partial vacuum is drawn to create pressure differential between interior sealed spaces of the packages and the exterior of the package seals. In some embodiments, flexible bladders are provided to initially seal opposite surfaces of packages having opposite gas permeable material covering layers.

Abstract: 1.

Abstract: A fixture for testing a sealed container for possible leakage, having a removable cover and a silicon gel gasket affixed to the undersurface of the cover, and having a lower housing with a cavity for receiving the sealed container, the container top surface being isolated from the rest of the container surfaces by the silicon gel gasket.

Abstract: An apparatus to test integrity of a seal of a package. The apparatus includes a height detector detecting a height of the package, a test portion determining the integrity of the seal based upon a position of the test portion as a function of time when contacting the package, and a mover moving the test portion into an initial position of contact with the package based upon the detected height. The test portion includes a test head contacting the package, and the mover includes a servo motor driving the test head, and a ball screw linking the servo motor and the test head.

Abstract: To test the tightness and/or the correct closure of containers which are transported on a conveyor, the containers succeeding each other at brief time intervals and the containers being sealed by attachment of a closure, a characteristic dependent on the internal pressure (internal-pressure characteristic) of the container is measured. Upon attachment of the closures to the containers, the internal-pressure characteristic or parameters of the closures or containers, knowledge which is necessary to measure the characteristic depending on the internal pressure, are recorded. The containers are marked no later than when the closure is attached in a way which permits the values recorded upon attachment of the closures to be allocated to the respective container.

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.

Abstract: Leak testing a closed container with at least one flexible wall area is performed with the method and apparatus wherein a biasing arrangement compresses or expands the container under test. A biasing force is monitored with a force detector applicable to the wall of the container. The force detector generates an electric output first biasing force signal at a first point in time which is stored for comparison with the monitored biasing force signal at a second subsequent point in time to generate a different signal as a leak indicative signal. A difference signal is generated at the first point in time from the first force measuring signal stored and the first force measuring signal. This latter difference signal is stored as a zero offset signal which is used to compensate zero offset of the generated difference signal.