Abstract: A sensor unit including a measuring cell with a section-wise heat-conducting surface, a housing in which the measuring cell for the most part is contained, and an access channel to the measuring cell. The sensor unit includes a cavity that is confined for the most part by an outer surface of the measuring cell and by a wall of the housing facing towards the surface of the measuring cell. The cavity is closed in itself.

Abstract: The invention relates to a method for determining the rate of leakage on a non-rigid specimen, wherein the specimen is introduced to a film chamber which can be evacuated, having at least one wall region made of a flexible material and the pressure in the film chamber is reduced outside of the specimen. The pressure gradient within the film chamber outside of the specimen is measured. In order to increase the accuracy of the leak detection, an outer over-pressure is exerted on the flexible wall region during pressure measurement which exceeds the pressure in the film chamber and outside of the specimen and the pressure inside the specimen.

Abstract: A sniffer leak detector includes a mass spectrometer for analyzing hydrogen or helium, a turbomolecular pump which is connected with said mass spectrometer and whose outlet is connected with a prevacuum pump, and a sniffer probe which includes a plurality of intake lines and is connected with said inlet of said turbomolecular pump, wherein a vacuum pump includes at least three stages whose inlet stage defines said prevacuum pump and is connected with said outlet of said turbomolecular pump via a blocked throttle, wherein, between adjacent stages of said vacuum pump, an intermediate inlet each is provided, wherein each intermediate inlet is connected with a different intake line of said sniffer probe and at least one of the intake lines as a suction line is connected with said inlet of said turbomolecular pump for obtaining different gas flows.

Abstract: A method for calibrating a test chamber, which encloses an interior volume (20), is designed as a film chamber (12) comprising at least one flexible wall region (14, 16), and is connected in a gas-conducting way to a pressure sensor (30), to a vacuum pump (26), and via a calibration valve (34) to a calibration chamber (36) enclosing a calibration volume (37), comprising the following steps: evacuating the film chamber (12); measuring the pressure difference inside of the film chamber (12); after the evacuation has been completed, connecting the calibration volume (37) in a gas-conducting manner to the interior volume (20) of the film chamber (12) while measuring the pressure change, wherein the pressure in the calibration chamber (36) is greater than the pressure in the film chamber (12) before the connection to the film chamber (12). A corresponding device is likewise disclosed.

Abstract: A method for testing the sealing tightness of a specimen, containing a gas, in a film chamber made from flexible material. The film chamber is evacuated by a vacuum pump and the gas flow flowing out of the film chamber and generated by the vacuum pump is measured during the evacuation and is examined with respect to a possible leak of the specimen.

Abstract: A double-acting refrigerant compressor includes a piston freely guided on two cylinder portions arranged opposite to each other and being immobile relative to each other. The piston includes a flow channel extending internally through the piston. Each cylinder portion and the piston include, along the flow channel, respectively at least one back-check valve. The back-check valves are arranged in such a manner that their flow directions are unidirectional.

Abstract: A method for performing a leak-tightness test on a test object (16) in a foil chamber (10) which has at least one flexible wall region (12, 14), having the steps: using a gas or gas constituent contained in the test object as test gas for the leak-tightness test, introducing the test object into the foil chamber, evacuating the foil chamber to a pressure lower than the test gas pressure within the test object and than atmospheric pressure, introducing a carrier gas into the foil chamber into the region outside the test object, and measuring the test gas concentration of the gas mixture that forms in the foil chamber in the region outside the test object.

Abstract: A method for testing a leak detector by using a leak detection device having a test leak and which is provided with a cavity that can be filled with gas, including the following steps: a) filling the cavity with ambient air up to an interior pressure in the interior of cavity that corresponds to ambient atmospheric pressure, b) establishing an exterior pressure in the area surrounding the leak detection device that is lower than the interior pressure, c) measuring the leakage rate of the air flowing through the test leak from the interior to the exterior of the leak detection device, and d) establishing an atmosphere consisting of ambient air with ambient atmospheric pressure as exterior pressure in the area surrounding the leak detection device.

Abstract: The invention relates to a leak detector comprising a first sensor for detecting a gas component (helium) in a gas taken in. Because the sensor is susceptible to saturation or contamination, a second sensor is provided. The sensor is a thermal conductivity sensor. The thermal conductivity sensor has a lower detection sensitivity, yet, at a high concentration of the gas component, it does not risk being contaminated. The two sensors together allow for a large detection range, from extremely sensitive measurements to instances with high concentrations of the gas components as those which can occur with gross leaks.

Abstract: A testing device includes a test gas container, which is provided with a test leak for producing a test gas flow at a predefined leakage rate. The test leak includes at least one capillary tube, which connects the interior of the test gas container to the outer surroundings of the test gas container in a gas-conducting manner. The test gas container is at least partially made of a flexible material.

Abstract: A simplified device for voltage supply of the cathode of a mass spectrometer comprises a push-pull transformer, wherein, apart from the normal rectifier diodes (7, 9), a controlled rectifier (8, 10) is provided. The gate of the first transistor (8) is connected to the second output (30), and the gate of the second transistor (10) is connected to the first output (32) of the transformer. A voltage supply device, consisting of at least one voltage multiplier, is connected via capacitors (13, 14, 15) to the output of the transformer and feeds, amongst others, the emission current measurement device.

Abstract: Vacuum pressure of a gas in a compartment (1) is measured. The vacuum pressure is established by a pump arrangement (3,5) with a pulsating pumping effect (g(t)). The shape of the resulting pulsation of the pressure (p(t)) in compartment (1) is exploited (15) as an indication of the operation status of the pump arrangement (3,5).

Abstract: The invention relates to a leak detector comprising a first sensor for detecting a gas component (helium) in a gas taken in. Because the sensor is susceptible to saturation or contamination, a second sensor is provided. The sensor is a thermal conductivity sensor. The thermal conductivity sensor has a lower detection sensitivity, yet, at a high concentration of the gas component, it does not risk being contaminated. The two sensors together allow for a large detection range, from extremely sensitive measurements to instances with high concentrations of the gas components as those which can occur with gross leaks.

Abstract: A sensor unit including a measuring cell with a section-wise heat-conducting surface, a housing in which the measuring cell for the most part is contained, and an access channel to the measuring cell. The sensor unit includes a cavity that is confined for the most part by an outer surface of the measuring cell and by a wall of the housing facing towards the surface of the measuring cell. The cavity is closed in itself.

Abstract: The leak detection appliance has a test inlet to which a test chamber containing the test specimen can be connected. A high-vacuum pump produces a high vacuum in a test gas detector. A backing pump contains two pump stages. In order to evacuate the test chamber, the pump stages are operated in parallel mode, with their suction capabilities being added. When the necessary vacuum has been achieved, the pump stages are operated in series in order to produce the necessary high vacuum which is required for high detection sensitivity on the test gas detector.

Abstract: An ionization vacuum measuring cell comprises an anode (3A) and a cathode (4K) in a measuring chamber (107). The measuring chamber (107) is arranged in a housing (101) which has a vacuum-tight feedthrough (103) for a connection rod (104) of the cathode (4K) towards the outside. The measuring chamber (107) holds the rod (104) in a feedthrough (109) which is electrically insulating only. The measuring chamber (107) in the housing (101) can be exchanged by a releasable plug connection (106).

Abstract: The invention relates to the use of an indicator for testing the tightness of water conducting components in a housing which is either mixed into the water or released upon contacting water drops or generated from a generative material upon contact with water. According to the invention, the presence of the indicator in gaseous or vaporous form is detected by a sensor.

Abstract: A fast method for determining molecular mass using mass spectrometry has the following steps: specifying a first adjusting value (M1) of the mass spectrometer, recording the associated signal amplitude (A1), specifying a second adjusting value (M2) which is different to the first, measuring the associated second signal amplitude (A2), specifying a third adjusting value (M3) which is different to the first (M1) and the second (M2) adjusting value, measuring the associated third signal amplitude (A3), determining a quadratic function containing the measured amplitude values as y-values and the specified adjusting values as x-values, determining the maximum of the quadratic function, wherein the searched adjusting value is determined from the x-value of the maximum.

Abstract: The invention relates to a method for determining the rate of leakage on a non-rigid specimen, wherein the specimen is introduced to a film chamber which can be evacuated, having at least one wall region made of a flexible material and the pressure in the film chamber is reduced outside of the specimen. The pressure gradient within the film chamber outside of the specimen is measured. In order to increase the accuracy of the leak detection, an outer over-pressure is exerted on the flexible wall region during pressure measurement which exceeds the pressure in the film chamber and outside of the specimen and the pressure inside the specimen.

Abstract: An ionization vacuum measuring cell has: a) an evacuatable housing (10) with a measuring connection (8) for the vacuum to be measured, b) a first outer and a second inner electrode (3, 4) which are coaxially arranged in an interspaced manner with a common axis (7), whereby a measuring chamber (20) is formed between the two electrodes, the measuring chamber communicating with the measuring connection (8), c) a voltage source (16) which is connected to the electrodes (3, 4), d) a current measuring mechanism (17) for analyzing a discharge current generated between the electrodes (3, 4), and e) at least one permanent magnet ring (1) which surrounds the coaxial electrode (3, 4) arrangement, has a magnetizing direction (13) directed radially to the axis, and has a soft-magnetic yoke (2) that surrounds the permanent magnet ring (1).