Abstract: The invention relates to a single flow friction vacuum pump (1) with a housing (4, 5) in which an inlet (2), the active pumping surfaces (8, 9) and a drive motor (11) are arranged axially behind each other; in order to effectively air-cool the pump, it is proposed that its housing walls be equipped with air intake and air discharge openings and that a fan (23) be integrated in its housing (4, 5). (Drawing FIG.

Abstract: A process for operating a dry-compression vacuum pump with at least one pump chamber and at least one rotor driven by an electric motor, and to a vacuum pump suitable for this operating process. To reduce operational shutdowns for maintenance purposes without any risk to the pump, it is proposed that application-specific phenomena leading to deviations from the normal operating status or their effects be monitored and, after a predetermined deviation quantity has been attained at which operation of the vacuum pump could be adversely affected in future, steps be taken to remove the causes thereof.

Abstract: A sealing system for an essentially vertical shaft includes an active sealing element disposed between a first structural part rotating with the shaft and a second structural part stationary on a housing. A wall of the housing separates an upper oil-free volume from a lower volume containing oil. The oil flows through the sealing system through a gap formed by the first structural part and a third structural part stationary on the housing. The active sealing element is preferably a threaded shaft seal. In another embodiment, the active sealing element is a combination of a primary contact seal and a threaded shaft seal. The oil flow removes heat generated by the rotating system.

Abstract: A penning type gauge head with an electrode system comprising an anode and a cathode disposed in the magnetic field of a permanent magnet, including an ignition aid for the electrode system. In order to provide rapid and reliable ignition, the ignition aid consists of a least one metal strip attached on the anode, and the free end of the ignition aid extends in the direction toward the cathode.

Abstract: The invention relates to a countercurrent sniffing leak detector (1) with a mass spectrometer (3) as the detector, with a high-vacuum pump (4) or high-vacuum pump stage (14) through which flows a test gas in countercurrent, with a sniffing hose (7) connected to the outlet side of the high-vacuum pump, respectively high-vacuum pump stage, and with a choke maintaining the pressure difference between the atmospheric pressure in the inlet region (8) of the sniffing hose (7) and the pressure in its outlet region (9); to improve the sensitivity and response time it is suggested that at least one segment of the sniffing hose (7), preferably the entire sniffing hose (7), is dimensioned such that the desired choking is achieved.

Abstract: A test gas leakage detection assembly (1) includes an inlet (2), a detector (3) in the form of a mass spectrometer, a first friction pump stage (5) which is driven in counter-flow, a second friction pump stage (7). The assembly further includes an intermediate connection (6) between the first and second friction pump stages, a pre-vacuum pump (8), a first connection line (13) which can be shut off between the leakage detector inlet (2) and the inlet side (9) of the pre-vacuum pump (8), and a second connection line (15) which can be shut off between the leakage detector inlet (2) and the intermediate connection (6). In order to detect leaks without using oil, the pre-vacuum pump (8) is a diaphragm pump. In order to shorten the response time, it is advantageous if the conductance of the second connection line (15) between the inlet (2) of the leakage detection assembly (1) and the intermediate inlet (6) is adjustable.

Abstract: A leak detection device includes a high vacuum pump implemented as a friction vacuum pump with two further vacuum pumps operating against atmospheric pressure. The further vacuum pumps are dry-sealing pumps in order to avoid hydrocarbon contaminations in a region of a test sample or a test chamber.

Abstract: This invention concerns a method of operating a cryogenic cooling device (1) with a cylinder (4, 5) in which a piston (6, 7) reciprocates and with a gas drive (8, 9) which produces the motion of the piston. In order to reduce the vibrations which occur during operation, the invention proposes that the gas drive (8, 9) is controlled in such a way that the piston (6, 7) is only accelerated for part of the stroke.

Abstract: The invention pertains to a vacuum pump (1) with a closable line (63, 102) through which gas ballast can be fed into the pump chamber (8, 9); to eliminate the danger that a recipient hooked up to the vacuum pump may be charged with air in the event of a pump failure, the invention proposes that the line be equipped with a control valve (59, 60, 61; 98, 99; 109, 110) to regulate the gas ballast feed as a function of operating conditions, such that the line is closed in the event of a pump failure.

Abstract: The invention relates to a vacuumtight connection between an (inner) channel (3) opening into the surface of the housing (2) of an appliance, pump or the like, the opening (4) of which is fitted with a sealing surface (5), and an (outer) line (6) having a flange (7) with a sealing surface (8) at the end to be connected to the channel (4); in order to make the connection compact and user-friendly, it is proposed that sealing surface (5) on the housing side and surrounding the opening (4) of the channel (3) be in the region of the housing surface and that, for the vacuumtight connection joint between the flange (7) of the outer line (6) and the housing surface, a securing plate (10) be used which lies on the edge of the flange (7) away from the housing (2) once the connection has been made. (drawing FIG.

Abstract: In a mask (7) for covering the outer marginal area of a disk-shaped substrate surface during a coating process, for example a vacuum sputtering or vapor depositing process, the mask (7) is made of an elastic material in the form of a planar plate with an essentially circular opening. To center and lock it onto the substrate (1) an inwardly extending annular flange is provided which assumes the actual masking function and extends in a plane parallel to the plane of the plate. The substrate (1) is laid on this flange and retained by projections extending radially inward. Prior to positioning the substrate it is bowed axially to spread apart the projections.

Abstract: A pivot arm (3) is rotatable about an axis for delivering and removing a flat workpiece (24) into and out of the area of the lock (19) of an evacuable coating chamber (26). The pivot arm (3) is provided at its distal end with the retaining bolt (12) which is perpendicular to the plane (20) of the lock opening (19) and attached to a central part of a flexible diaphragm. The diaphragm is substantially parallel to the sealing surface of a workpiece carrier (16) and is fixed around its outer radial edge to the workpiece carrier so that the workpiece carrier (16) is able to tilt slightly during its vertical closing motion.

Abstract: In a moisture sensor (1), the effective sensor field (4) is formed by two sensor elements (8a, 8b,) having interdigitating parallel tracks. These sensor elements consist of layers of a metal nitride compound, especially a chromium-nitrogen compound, deposited by means of magnetron cathode sputtering or glow discharge onto a dielectric substrate (2), the metal nitride layers being deposited onto the substrate surface which has first been cleaned by ion sputtering. These sensor element layers (8a, 8b) have a high hardness of about 2,000 on the Vickers scale, as a result of which the sensor elements (8a, 8b) are highly resistant to abrasive wear such as that caused by windshield wipers or scratching from ice. The moisture sensor can be produced with a low electrical surface resistivity of <100 ohms.quadrature. and is chemically stable with respect to environmental effects such as salt water and/or windshield cleaning fluids.

Abstract: A search gas detector for leak detection instruments includes a gas inlet, a vacuum pump, and an apparatus by which the presence of a search gas is recorded. The vacuum pump is able to pump all reactive gases and the search gas recording apparatus is able to detect enrichments of the search gas. More preferably, the gas inlet is effective for permitting only the search gas to pass therethrough, the detector having a pair of chambers, the first to which the gas inlet and search gas apparatus are connected, and the second to which the vacuum pump is connected. The two chambers are interconnected by a constrictive line with the first chamber having a relatively large volume in relation to the second chamber.

Abstract: A measurement amplifier has an integrator circuit (2) and a reference current source (33) which supplies a reference current to the input of the integrator when the voltage set at the output of the integrator (2) exceeds or falls below a reference voltage. In addition, a differentiator, for example, is provided which receives the output voltage of the integrator (2) and supplies an output signal which is proportional to the variation in time of the output voltage of the integrator. The output voltage of the differentiator is proportional to the input current to be measured by the measurement amplifier. The measurement amplifier allows very weak input currents to be rapidly and accurately detected.

Abstract: A rotating head (11) for crystal pulling systems (1) according to Czochralski has a reference platform (16) which is able to rotate around a vertical rotation axis (A--A) with a vertical feed-through opening (25) for a pulling cable (13) that can be wound up and a drive assembly (23) for driving a shaft (22). A winding drum (15) with a helical winding groove (29) for the pulling cable is located on this shaft in a fixed manner so it cannot rotate, but can be moved axially. In order to avoid abrasion and contamination and to accurately guide the cable (13), a helical guiding element (30) with the same pitch as the winding groove is located on the shaft (22) at a location remote from the vertical rotation axis (A--A). This guiding element is able to rotate with the shaft. The guiding element works together with a guiding nut (31) in such a way that the part of the cable (13) which faces tangentially away from the winding drum (15) is directly guided in the vertical rotation axis (A--A).

Abstract: The invention pertains to an oil-sealed vacuum pump (1) with a pump chamber (8, 9), with a rotor 3 rotatively mounted therein, with a bearing piece (13) delimiting the pump chamber on the drive side and with a passage (35) in the bearing piece (13) which contains a coupling piece (37) used to interlock the rotor (3) with the shaft (36) of the drive motor (4) and a sealing ring (55) to seal off the coupling piece from the passage (35) in the bearing piece (13). To simplify manufacture of the pump, the invention proposes that the interlocking connections between rotor (3) and coupling piece (37) as well as coupling piece (37) and shaft (36) are effected from the faces, and that the coupling piece (37) is a support for a rotor (46) for an oil pump (45, 46), the pump chamber (45) of which is formed in the end plate (13).

Abstract: The invention relates to a rotationally symmetrical.sup.1 magnetic bearing cell (1) with a rotor (2) arranged to rotate about the central axis (10) of the cell (1) and having a shaft (4) and at least two axially magnetised permanent magnetic rings (5, 6, 30) fitted an axial distance apart on the shaft and with a stator (3) having pole components (12, 13, 16, 17) and two annular coils (14, 15) associated with the rotor end faces; to improve the radial rigidity without increasing active control complexity, it is proposed that pole components (26, 27, 38) of magnetically conductive material be provided for the peripheral regions of the two axially outer permanent magnet rings (5, 6 or 5, 30) to direct the magnetic flux generated by the annular coils (14, 15) into two substantially independent magnetic flux circuits (28, 29)..sup.1 Translator's: note The German text reads "aufgebautet". This is grammatically not correct. Instead the German text should read "aufgebaute".

Abstract: A process for operating a dry-compression vacuum pump with at least one pump chamber and at least one rotor driven by an electric motor, and to a vacuum pump suitable for this operating process. To reduce operational shutdowns for maintenance purposes without any risk to the pump, it is proposed that application-specific phenomena leading to deviations from the normal operating status or their effects be monitored and, after a predetermined deviation quantity has been attained at which operation of the vacuum pump could be adversely affected in future, steps be taken to remove the causes thereof.

Abstract: A leak detector (1) suitable for detecting leakage with a test gas connection (2), a test gas detector (3), a gas pump (4) and a test gas line (5) extending between the test gas connection (2) and the gas pump (4) and connected to the inlet (6) of the test gas detector (3) via a blockable branch; in order to shorten the response time, it is proposed that the line (7, 8) connecting the test gas line (5) to the inlet region (6) of the test gas detector be such that, during measurement, all of the gas flowing in the test gas line (5) essentially enters the inlet region (6) of the test gas detector (3).