Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A rotary pump, preferably a vacuum pump, featuring: a delivery space including an inlet on a low-pressure side and an outlet on a high-pressure side of the pump; a rotor which is arranged in the delivery space and delivers a fluid from the inlet into the delivery space to the outlet from the delivery space; at least one housing part which delineates the delivery space at least axially; and a drive shaft which is connected in drive terms to the rotor; including at least one sealing element which is connected, secured against shifting and/or rotating, to the drive shaft and/or rotor and forms a radial sealing gap with the housing part.

Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A scroll fluid machine that attenuates the bending stress applied to the base of a wall body having an inclined section. The scroll fluid machine is provided with a wall body inclined section in which the distance between the facing surfaces of an end plate of a fixed scroll and an end plate of a rotating scroll that face each other continuously decreases from the outer circumferential side toward the inner circumferential side. A mesh clearance that is a gap between wall bodies formed when the wall bodies mesh with each other is larger on the outer circumferential side of the inclined section than on the inner circumferential side of the inclined section. The mesh clearance is made larger by drawing the wall surface of a wall body further back toward the central side of the wall body in the thickness direction than the original wall surface profile thereof.

A dry vacuum pump may include a stator which defines an internal chamber in which a rotor is rotationally mounted. A sensor is mounted to the stator and has an output connected to a processing circuit arranged to analyse the output of the sensor to determine the absolute distance between a point on the surface of the rotor and internal stator surface. The rotor to stator clearance can thus be accurately determined in real time during operation of the pump, so that the pump performance can be optimised over its serviceable life.

A fixed scroll wrap (52) includes a fixed spiral portion (57) having a spiral shape and a fixed arcuate portion (58) having an arcuate shape. A movable scroll wrap (62) includes a movable spiral portion (67) having a spiral shape and a movable arcuate portion (68) having an arcuate shape. An arcuate portion side surface clearance (GA) is defined by the fixed arcuate portion (58) and one of the movable spiral portion (67) and the movable arcuate portion (68), or is defined by the movable arcuate portion (68) and one of the fixed spiral portion (57) and the fixed arcuate portion (58). A spiral portion side surface clearance (GI) is defined by the fixed spiral portion (57) and the movable spiral portion (67). The arcuate portion side surface clearance (GA) is larger than the spiral portion side surface clearance (GI).

In a scroll compressor (1) provided with a fixed scroll (3) and an orbiting scroll (5), an inclined portion is provided in which the inter-facing surface distance (L) between an end plate (3a) and an end plate (5a) that face each other decreases continuously from the outer peripheral side towards the inner peripheral side. The inclined portion is configured from wall inclined portions (3b1, 5b1) in which the height of a wall (3b, 5b) decreases continuously from the outer peripheral side towards the inner peripheral side, and end plate inclined portions (3a1, 5a1) in which a tooth bottom surface is inclined in accordance with the incline of the wall inclined portions (3b1, 5b1). The inclined portion is provided across a range of no less than 180 around the center of the spiral.

A Rotary Claw Pump with at least one pair of intermeshing rotors has the same shape within a tolerance of 3% of the radii from edges to rotational centers. A convex portion of the claws has a nominal uniform rate of radius change with angle of rotation. There may be multiple stages wherein the thickness of each successive rotor pair maintains profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. A discharge port is at least partially uncovered at any position of rotation from where intermeshing claw rotor tips are closest to where they are most distant. The discharge port is at least partially connected with a region connected with the rotor tips of both claws during rotation. The discharge port limits pressure increase in the region.

An oil pump, in particular an electric or electromotive auxiliary pump for a motor vehicle, having a housing having an inlet on the admission side and an outlet on the pressure side, in addition to a pump rotor which is inserted in the housing such that it can rotate about an axis, and having at least one rotor part, a flexible housing component which is in the form of an elastic press plate and which extends over the cross-sectional surface of the pump rotor. The flexible pressure plate is maintained, in an advantageous manner, in the edge area of the second housing parts.

The present invention provides a method of ceasing rotation of a rotor of a vacuum pump. The method comprises the steps of rotating the rotor at an intermediate RPM, at which there is substantially no probability of the rotor clashing with the stator, for a dwell time sufficient for the vacuum pump to be at or below a threshold temperature, and subsequently coasting down the rotation of the rotor until cessation of rotation.