Abstract: In order to functionally test a leak detector (20) that comprises a partial pressure sensor (21), a testing device (30) having a variable volume (33) is connected to the leak detector. Said testing device can be a syringe. By changing the volume (33), the partial pressure of the test gas contained in the ambient air is changed. A test is carried out to check whether the leak detector (20) indicates the change. According to the invention, a vacuum pumping device having mechanical vacuum pumps is not required. The method is suitable for testing vacuum systems that contain a vacuum pumping device that is used in the leak test to generate a required vacuum. The service technician can perform the functional test of the leak detector (20) separately from the system and the vacuum pumping device.

Abstract: A cathode configuration for emission of electrons has a reaction zone connected to an entrance opening for the supply of neutral particles. The opening communicates with the cathode configuration for the ionization of the neutral particles and an ion extraction system communicates with the reaction zone. Ions from the extraction system are sent to a detection system and a mechanism for the evacuation of the mass spectrometer arrangement. The cathode configuration includes a field emission cathode with an emitter surface, wherein at a short distance from this emitter surface, an extraction grid is disposed for the extraction of electrons, which grid substantially covers the emitter surface. The emitter surface encompasses herein at least partially a hollow volume such that a tubular structure is formed.

Abstract: A cathode configuration for emission of electrons has a reaction zone connected to an entrance opening for the supply of neutral particles. The opening communicates with the cathode configuration for the ionization of the neutral particles and an ion extraction system communicates with the reaction zone. Ions from the extraction system are sent to a detection system and a mechanism for the evacuation of the mass spectrometer arrangement. The cathode configuration includes a field emission cathode with an emitter surface, wherein at a short distance from this emitter surface, an extraction grid is disposed for the extraction of electrons, which grid substantially covers the emitter surface. The emitter surface encompasses herein at least partially a hollow volume such that a tubular structure is formed.

Abstract: In the leak detection method, it is provided that a specimen (24) filled with a test gas is positioned in front of a suction opening (11). The suctioned air brushes along the surface of said specimen and takes up test gas in the case of a leak. Said test gas is recognized by a test gas detector (17,17a). According to the invention, full mobility of said specimen (24) is ensured during the testing process such that a test can also be carried out while said specimens are moving past said suction opening.

Abstract: A stack (10) of fuel cells (11) is to be tested for tightness of the fuel cell membranes. For this purpose, a tracer gas is introduced into the fuel feed channel (15) of the stack (10). The fuel discharge channel (16) is either open or it is closed. A carrier gas is fed to the feed air channel. (17) and led through the exhaust air channel (18) to a gas sensor (28) where a determination is made whether the carrier gas contains amounts of tracer gas. A defective fuel cell (11) can be located by introducing a lance comprising a sniffing probe into the corresponding channel (18) and determining the position of the probe.

Abstract: A vacuum pressure measuring device with an electron source has a reaction zone for forming ions by impact ionization, wherein the electron source communicates with the reaction zone via a passage for the electrons. The electron source is surrounded by an insulating housing with a vacuum chamber, and a partition part is designed as a membrane carrier, carrying a nanomembrane at least in one section, the membrane separating the vacuum chamber from the outer region in a gastight manner and being at least partially designed to be electron-permeable. The vacuum chamber has a cathode for the emission of electrons. In the region of and/or on the nanomembrane, an anode arrangement is provided such that electrons are conducted against the nanomembrane and at least partially through it. The nanomembrane abuts the vacuum chamber of the vacuum pressure measuring device.

Abstract: A sniffer leak detector comprising a detector with a quartz window, the window being selectively permeable to a tracer gas. The quartz window is located in a suction chamber that is connected to a vacuum pump. To reduce the response time, a gas guidance plate is situated in the suction chamber, the guidance plate and quartz window together delimiting a narrow gas guidance chamber.

Abstract: The gas sensor has a selectively permeable membrane which is composed of silicon material and is provided with a heating device on the outside. The membrane closes an evacuated housing which contains a pressure sensor. When evacuating the area surrounding the housing, the heat dissipation is changed as a result of the quick change in the total pressure of the surrounding air, with the result that signal drift arises despite temperature regulation of the membrane. The disclosure provides at least one second heating device whose temperature is regulated independently of the first heating device. As a result, the membrane temperature is highly constant even in the case of severely changing total pressure in the housing.

Abstract: The invention relates to a vacuum measuring cell device comprising a vacuum membrane measuring cell (8) having a connecting means (5, 6) arranged thereon for a communicating connection to the medium to be measured, an electronic system (34), which is electrically connected to the vacuum membrane measuring cell (8), and also comprising a heating arrangement (20, 21) for heating the vacuum membrane measuring cell (8) to a predefinable temperature value, wherein the heating arrangement (20, 21) substantially encloses the entire vacuum membrane measuring cell (8) such that said cell forms a thermal container (20). Said container constitutes a thermal body (20a) in the area of the connecting means (5, 6) and connecting means (6) are guided through it, the connecting means thereby being thermally contacted at least in some areas by the thermal body. The thermal container (20a) comprises a heating source (21) for the heating thereof.

Abstract: A flange connection has two pipe ends (1?, 2?, 51?, 52?) on each of which one flange (1, 2, 51, 52) is disposed and which have flange faces (11, 11?, 61, 61?) and a centering ring (33, 34) with an elastomer sealing ring (14) in contact with the ring. Both flanges include a mechanism for the detachable clamping against one another such that the flange faces (11, 11?, 61, 61?) are in contact on the centering ring and thereby are held at a predetermined flange distance (10, 60, D). The elastomer sealing ring (14) is pressed on the flange faces (11, 11?, 61, 61?) in the direction of the pipe axes (15) forming a seal, wherein the centering ring (33, 34) is positioned such that it is at least partially in contact on the periphery of the flanges (1, 2, 51, 52).

Abstract: The helium sensor comprises a housing that encloses a detection chamber. A side of the housing is closed by a permeable wall that is selective for helium. In the detection chamber, there is located an ion getter pump comprising an anode, a cathode and a magnetic field. The cathode, or a cathode leg is made of beryllium. Beryllium has a low atomic mass, whereby the likewise light-weight helium ions can be better incorporated into the cathode material.

Abstract: The leakage search assembly has a main device which contains a vacuum pump and a test gas sensor, and a hand-held sniffing probe. Capillary lines which connect the sniffing probe to the basic assembly contain valves by means of which these lines can be selectively opened. In a leakage search mode, the capillary line having the larger cross section is open. This results in leaks also being found from a greater distance. The dead time before response of the test gas sensor is shortened. Once a leak has been located, the assembly is switched to the leakage rate measurement mode, in which only the capillary line with the smaller cross section is open. This results in quantitative determination of the leakage rate with high accuracy and high stability.

Abstract: Method for producing a vacuum measuring cell having a pressure transducer diaphragm with housing plates sealed on opposite sides to form reference and measuring vacuum chambers. An opening in one plate communicates with the measuring vacuum chamber and has a sealed connection for joining to medium to be measured. The diaphragm and plates are aluminum oxide ceramic and at least one of the seals is aluminum with a thickness of 0.5 ?m to 30 ?m. The ceramic parts are pressed together at increased temperature of 600° C. to 680° C. in a process gas atmosphere including a reducing gas, during a time of 30 to 90 minutes, and subsequently a tempering step is carried out in a second process gas atmosphere including oxygen, tempering taking place at a temperature of 450° C. to 575° C. such that the metallic aluminum is oxidized into aluminum oxide.

Abstract: A sniffing leak detector which comprises a first suction line in a sniffing probe, the line leading to a main device, is provided with a larger second suction line through which gas is sucked in from the sniffing tip by a gas delivery pump. By connecting the second suction line, the distance sensitivity is increased. By disconnecting the second suction line, on the other hand, the sensitivity is increased. Thus, it is possible to first search for leaks by use of a high gas throughput and subsequently exactly determine the leaks under the quantitative aspect by use of a reduced flow.

Abstract: In leak detection, the signal generated by a test gas is superposed by interferences which fade as the vacuum generation in a container proceeds. Depending on the negative slope of the volume signal (MS), a lower indication limit (AG) is calculated. Upon activation of a zero function, the volume signal (MS) is not reduced to zero but only to the level of the indication limit (AG). Any exceeding of the indication limit is identified as a leak. Thus, the maximum sensitivity of the leak detection is guaranteed at any time.

Abstract: A selective gas sensor is for determining the presence of a test gas, for example, helium includes an evacuated housing, sealed by a selectively gas-permeable membrane. The membrane is part of a sight glass, whereby the glass pane is provided with a hole, sealed by the membrane made from a silicon material. The frame of the membrane wall is connected to the housing by means of a high-vacuum soft-metal seal. The housing can also form one of the electrodes of the gas pressure sensor.

Abstract: A cold cathode pressure sensor has gastight housing, an anode and a cathode arranged in the housing, and a radiation source directed to the cathode for igniting a cold cathode discharge. The housing has a test gas inlet and is at least partly made of glass. The radiation source is arranged outside the housing and irradiates the cathode through the housing glass. The radiation source substantially emits a radiation of a wavelength of more than 400 nm and less than 1,400 nm.

Abstract: The leak detector includes a basic device which includes a vacuum pump, a test gas sensor, and a hand-held sniffing probe. The sniffing probe is connected with the basic device via a flexible hose line which includes capillary tubes. At least two capillary tubes are provided, which are adapted to be opened via valves. Thus different capillary cross sections can be rendered operative. The dead time between the entry of the test gas into the sniffing probe and the detection by the test gas sensor can be changed and/or selected. Thus, even the smallest detectable leak rate can be changed and/or selected. The leak detector can be adapted to different requirements by the user without the need for exchanging the hose line. Further, it is possible to equip different leak detectors of the same device family with the same hose lines.

Abstract: A vacuum measuring cell with a membrane between two planar housing parts has a first housing part forming a reference vacuum volume and the second housing part forming a measuring vacuum volume with a connection for the medium to be measured and a mechanism for measuring the membrane deflection. The membrane surface exposed to the medium to be measured is a structured surface.

Abstract: For evaluation of a measured parameter with a measuring cell having a cavity which generates for light an optical path length difference changing corresponding to the variation of the measured parameter, the method includes: introducing light from a white light source with the aid of an optical waveguide via a coupler (3) disposed in the path of the optical waveguide into the cavity, coupling out at least a portion of the light reflected back into the optical waveguide from the cavity with the aid of the coupler and conducting this reflected light to an optical spectrometer, determining the optical spectrum of the reflected light in the spectrometer and generating a spectrometer signal, conducting the spectrometer signal to a computing unit, wherein the spectrometer signal is directly converted through the computing unit to an interferogram and from its intensity progression the location of the particular extremal amplitude value is determined and this particular location represents directly the particular va