Abstract: A pump stand (1) has a base plate (2) for mounting thereon a pump (3) and at least one of a control unit (6) and a vacuum controller (7). The pump stand (1) has for this purpose a plurality of push-in or snap-in connections (5) enabling pump components or accessory units, particularly the pump (3) itself, to be simply exchanged. By this means a pump stand (1) of straightforward arrangement ensues, which provides a large number of possibilities for variation and can be simply combined with pumps of different type or different output.

Abstract: A measuring gas pump (1) has a pump chamber (3) closed by means of a working diaphragm (6). The strokes (double-headed arrow 26) are imparted to the working diaphragm (6) by way of a connecting rod or like lifting mechanism (9) from a crank mechanism (10). A heat source (16) is provided in the pump head (15). Provided between the connecting rod head (8) and the crank mechanism (10), there is a heat dissipation barrier (19 and/or 27) with respect to the measuring gas. By means of the measuring gas pump (1), the gas to be delivered thereby can be kept better to the temperature of the gas sampling condition and unwanted condensation of constituents of the gas to be analyzed and falsifications of the measurement result can be avoided or at least significantly reduced.

Abstract: A two-stage positive displacement pump (1) is used in particular to operate in conjunction with a turbomolecular pump (2) that can be placed ahead of it in series. The two-stage positive displacement pump (1) is configured as a hybrid pump (3) that has on the medium-entry side a reciprocating pump (5) with a comparatively large displacement area (6), whereby its piston-cylinder space (7) is sealed off with respect to the crank area (8) by means of a sealing membrane (9). Also as a part of this two-stage positive displacement pump (1) which forms the hybrid pump (3), there is placed in series behind the reciprocating pump (5) a diaphragm pump (10), whose displacement area (11) is noticeably smaller compared to that of the reciprocating pump (5).

Abstract: A diaphragm pump has a first fluid-operated valve which opens when the diaphragm performs a suction stroke and a second fluid-operated valve which opens when the diaphragm performs a compression stroke. The volumetric efficiency of the pump is enhanced by constructing at least one of its valves in such a way that the central portion of a resilient disc-shaped valving element, whose marginal portion bears against a seat when the valve is closed, abuts a supporting surface having a diameter selected in dependency on the diameter of the valving element, the thickness of the valving element and the Shore hardness of the material of the valving element in such a way that the selected frequency of the diaphragm in actual use of the pump induces a resonant frequency of the valving element. This also contributes to a reduction of noise and renders it possible to reduce wear upon the valving element and the adjacent parts of the respective valve.

Abstract: A diaphragm pump wherein the marginal portion of a contoured diaphragm is clamped between the cover and the case of the pump housing and the reinforced central portion of the diaphragm is reciprocated toward and away from the inner side of the cover by the connecting rod of a crank drive. The front side of the diaphragm and the inner side of the cover define a variable-volume pumping chamber which receives a fluid medium by way of an inlet and discharges the aspirated fluid medium by way of an outlet in the cover. The diaphragm has an intermediate portion which connects the central and marginal portions and is provided with an annular flexure zone including an annular protuberance at the rear side of the diaphragm.

Abstract: A diaphragm pump wherein that side of the diaphragm which faces away from the pumping chamber is adjacent a noise intercepting insert. The insert is traversed by the connecting rod of the drive which oscillates the central portion of the diaphragm to draw a fluid into and to expel the drawn fluid from the pumping chamber. A deformable wall of the insert has a marginal portion which is attached to the housing, and this wall is separated from the diaphragm by an elastic distancing cushion of foam rubber or other sound absorbing material. The cushion can constitute a ring or it can consist of a set of projections which are affixed to or integral with the wall and face of the diaphragm. The cushion is compressed between the head of the connecting rod and the wall so that the latter is maintained in stressed condition.