Abstract: Usually, a sniffing leak detector must be calibrated for each tracing gas. The calibration comprises ranging of the spectral positions into the mass spectrum and the amplitude height. At least one mass line is determined with a calibrating gas. The mass lines lying between two mass lines and/or between a zero point and a line are determined by interpolation and/or extrapolation. In this manner, a sniffing leak detector can be used for such tracing gases which have not previously been used for calibration purposes.

Abstract: For leak testing, a tracer gas is advanced to the outer wall (11) of the hollow test object (10) while the test object (10) is in an evacuated state. The tracer gas is discharged from a blower device (14) in the form of soap bubbles (21). When contacting the outer wall (11), the soap bubbles will burst, thus forming a cloud (27) of tracer gas immediately on the outer wall (11). By the invention, it is made easier to localize the invisible tracer gas in the ambient air. Further, the tracer gas can be used more effectively so that the costs for performing the testing process are reduced.

Abstract: The leak detector comprises a basic unit that is connected to a probe by a hose. The probe tip is placed against test zones of the test object. In case that test gas escapes from the test object, this is detected by a test gas detector in the base unit. According to the disclosure, a position determining system is provided which comprises a transmitter, a receiver that is disposed inside the probe, and a supply and evaluation unit. Thereby, the presence of the probe tip in the individual test zones is monitored and confirmed.

Abstract: In order to determine leakage on a device, which contains gas that can be condensed, an adsorbent is used through which ambient gas of the object is conducted. The adsorbed gas is desorbed by means of actuating an excitation device and fed to a gas sensor containing a mass spectrometer. In this way, minute amounts of leaking gas can be determined by means of accumulation. The method is in particular suited for use in the serial production of refrigeration machines.

Abstract: A method for forming an ultra-thin membrane for use in a chemical analyzer such as a mass spectrometer includes the step of applying a sacrificial blocking layer onto a porous substrate, applying a semi-permeable membrane layer onto the sacrificial blocking layer, and removing the sacrificial blocking layer following cure of the membrane layer. In a preferred version, at least one of the blocking layer and the membrane layer are applied to the porous support by means of spin coating, though other deposition techniques can be employed.

Abstract: A method for accurately calculating the thickness of deposited thin film layers onto a piezoelectric crystal blank in which dissimilar materials can be utilized, enabling determinations for various applications employing exotic materials. Additionally, the specific acoustic impedance (or equivalent z-ratio) of an unknown deposited material can be determined. The exact analytical solution nearly eliminates thickness errors when several layers of different materials are sequentially deposited on the same monitor quartz crystal.

Abstract: An apparatus for heating a surface to liberate at least one analyte for detection thereof includes a source of energy to irradiate the surface and a collector to collect at least one gas from the surface, the at least one gas being capable of including the a least one liberated analyte. The apparatus further includes a detector linked to the collector to detect the presence of the at least one liberated analyte wherein the detection is used to control the power of the energy source by utilizing feedback relating to at least one condition of the surface.

Abstract: The invention relates to a sniffing leak detector comprising a sniffing line (11) and a feed line (33) that leads to a vacuum pump (16). A distribution point (24) from which a branch line (25) leads to a test gas sensor (15) is provided on the feed line (33). In order for the intermediate pressure (P2) at the distribution point (24) to be independent of feed fluctuations of the vacuum pump (16), a throttle (D2) comprising a supercritically operated orifice (20) is provided between the distribution point (24) and the vacuum pump (16). The pressure drop at the orifice (20) is greater than half the intermediate pressure (P2) at the distribution point (24). The flow at the orifice (20) is thus blocked, wherein the flow (Q) remains constant regardless of changes of the pump pressure (P3). Changes of the intermediate pressure (P2) are thus prevented so that the sensitivity and signal stability of the test gas sensor (15) is unaffected by changes of the pump pressure.

Abstract: A sniffing leak detector which comprises a mass spectrometer, a turbomolecular pump and a forevacuum pump. In case that the sniffing hose with the hand-operated sniffing probe becomes detached from the main device, atmospheric pressure would pass into the gas inlet conduit and disrupt the high vacuum in the mass spectrometer. In order to protect the mass spectrometer and the vacuum pump apparatus, a flow restrictor with an upstream filter is arranged in the gas inlet conduit.

Abstract: To achieve a large measurement range from small up to larger leakage rates, a switchover from normal operation to gross operation occurs. In gross operation, the sucked-in gas flow is separated by different throttles, wherein the throttle that leads to the test gas sensor has a low flow rate. This manner of operation prevents a too large quantity of test gas from reaching the sensor surface and contaminating the sensor. In another alternative, in gross operation the test gas flows only across a part of the sensor surface. The other part is flushed.

Abstract: For refrigeration units, maintenance machines are required that can receive and compress the refrigerant from the refrigeration unit. Furthermore, a vacuum pump is required, which is connected to the emptied lines and pumps out humidity and air. The maintenance machine according to the invention includes a motor that drives a compressor via a freewheel in one rotational direction. The same motor drives a vacuum pump via a second freewheel in the other rotational direction. The maintenance machine, which can perform two different functions, includes only one single motor. The machine is lightweight, so that it can be carried by the maintenance personnel. Furthermore, it is small and can be produced in a cost-effective manner.

Abstract: A hydrogen sensor includes a housing, which is closed off by a membrane that is made of palladium and selectively only pervious to hydrogen. The housing is evacuated and contains a Pirani pressure sensor. The membrane and the Pirani pressure sensor are each attached to a carrier. Both carriers are joined directly next to one another or kept at a distance by a connection piece. The hydrogen sensor has a high sensitivity and a low response time due to the relatively large membrane surface and the low housing volume. It can be produced in a small size and integrated in the handle of a sniffer-type leak indicator.

Abstract: A valve arrangement has an annular housing with valve seat and a two-part valve plate that is rotatable about an axis. The seat is in the form of a disk including two adjacent openings with a web between and the axis is parallel to the web. The two parts of the valve plate are next to each other with their planes parallel and offset in a perpendicular direction. They are connected to each other through one of the openings by a connection piece extending through the one opening. In a closed position for the valve, the valve plate part are respectively positioned on opposite sides of the valve seat and cover and seal the respective openings due to a seal that is between the valve plate parts and the valve seat.

Abstract: A leak detector comprising a base appliance provided with a gas detector, a vacuum pump, and a control device. A sniffer probe is connected to the base appliance. A test leak device containing the supply of test gas is arranged in a separate sub-housing. The sub-housing also contains a temperature sensor, a processor, and a data memory. The processor corrects the measured temperature according to a sample, and modulates the light of a light barrier. The processor is connected to the control device in the base appliance by a data cable.

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.