The present invention relates to a rotor for a vacuum pump 150 having a roots pumping mechanism, the rotor comprising at least two hollow lobes 160, 162, 164, 166, each lobe having an outer wall 208 which defines a lobe profile, a hollow cavity 210 generally inward of the outer wall, and at least one strengthening rib 226 located in the cavity to resist stress on the lobes generated during rotation.

A rotary positive displacement device comprises a housing having low and high pressure ports; first and second rotors each having a frusto-spherical outer surface, an axial surface, a shaft and a rotational axis. The axial surfaces comprise a teardrop surface and an involute surface together defining a lobe and a corresponding valley. High and low pressure openings each extend between the first and second rotors and the corresponding high and low pressure ports. The first and second rotors intermesh so that the at least two chambers are separated by the axial surfaces of the first and second rotors, each chamber having a variable volume as the first and second rotors rotate about their respective rotational axes. A lower edge of the high pressure opening is positioned along an outer diameter of the outer surface of the second rotor and between the second rotor shaft and the first rotor valley.

A stator for a pump, in particular for a rotary piston pump or an eccentric screw pump, having a base body, wherein the base body surrounds a pumping area for a rotor arrangement of the pump, includes a support body and a running body, and the running body configures a running surface for at least partial contact with the rotor arrangement of the pump, wherein the support body and the running body includes a common material and wherein a material density of the material of the support body and a material density of the material of the running body are configured differently from one another, so that a different elasticity and/or a different hardness of the material is achieved in the support body and in the running body by means of the differently configured material densities. Furthermore, the invention relates to a method for producing such a stator.

A roots pump comprising: a rotary shaft; a rotor having a hole-forming surface that forms an insertion hole, and a first bearing and a second bearing. Each of the first bearing and the second bearing includes an inner ring and an outer ring. The rotary shaft is press-fitted in the inner ring of the first bearing, and fitted in the inner ring of the second bearing with a clearance between the rotary shaft and the inner ring of the second bearing. An edge portion of the hole-forming surface adjacent to the first bearing serves as a press-fitting portion in which the rotary shaft is press-fitted, and at least an edge portion of the hole-forming surface adjacent to the second bearing serves as a clearance-fitting portion in which the rotary shaft is fitted with a clearance between the rotary shaft and the clearance-fitting portion.

Designs for multiple segment lobe pumps are shown. The designs include pumps using rotors having two lobes to a plurality of lobes and segments that include two segments to a plurality of segments. Designs for both vertical, or straight walled conventional lobed rotors, as well as helical lobe rotors are shown. The designs are applicable to a variety of rotors and number of segments. In one particular case the designs enable a three lobe helical pump. Designs are also shown for separation plates used between the multiple segments. The separation float between the pairs of lobes in a segment and can also have a fixed position between the lobes by inclusion of end pieces that enable clamping of the separation plates in position.

In a rotating pump having at least one driven conveying element which is arranged in a product space, flowed through by the product to be conveyed, and is driven by means of a shaft which protrudes into the product space from the outside, the shaft being sealed with respect to a wall of the product space, the seal is configured as a slide ring seal to be mounted on the product side with an outer positively locking positional securing means.

The invention relates to a rotary lobe pump for conveying a fluid medium containing solids, comprising an inlet and an outlet for the medium being conveyed, and further comprising a pump casing and two rotary lobes arranged in said pump casing and having intermeshing rotary lobe vanes. According to the invention, the pump casing has two opposite casing half-shells which seal the pump casing fluid-tightly. The casing half-shells are double-walled.

A method of treating, tuning, assembling, and/or overhauling a twin rotor device (200, 1200) includes applying a coating material (102) on an internal set of working surfaces (218, 222, 224, 226, 228, 1218, 1222, 1224, 1226, 1228) of the twin rotor device when at least partially assembled. The coating may be factory or field applied to a new or used twin rotor device. The working surfaces may be uncoated or previously coated and may be built-up as the coating material forms a coating (206, 1206) on at least some of the working surfaces. Manufacturing variations of a pair of rotors (220, 1220) and a housing (210, 1210) may be compensated by the coating. One or more performance characteristics of the twin rotor device may be improved by the coating, and variation between a series of twin rotor device may be reduced or substantially eliminated. The coating may reduce internal leakage and increase volumetric efficiency of the twin rotor device. The twin rotor device may be a supercharger 200, a screw compressor 1200, or other twin rotor device.

The present teachings generally include a rotor assembly having a plurality of rotor sheets or layers mounted to a shaft, and methods of construction for a rotor assembly. Each rotor sheet or layer in the assembly may be provided with a central opening extending between the first and second sides through which the shaft extends. In one aspect, the rotor sheets or layers can be provided with a plurality of lobes extending away from the central opening, wherein each of the lobes can have a lobe opening extending through the thickness of the sheets or layers. In one example, the rotor sheets or layers can be rotationally stacked to form a helical rotor. In one example, the rotor sheets are formed from a pre-cured composite material and are bonded together with an adhesive.

A rotary piston pump with at least two double- or multi-lobe rotary pistons rotating in opposite directions, the drive shafts whereof include seals, wherein the seals are constituted as slip ring seals or lip seals or stuffing-box seals, which in each case are disposed on the shaft shoulder belonging to the respective rotary piston, and one slip ring per seal is provided with a locking device, which includes a large number of fixing positions. The seals are pushed onto a tubular shoulder of the rotary piston, the rotary piston is introduced into the pump housing, the securing element is connected to the slip ring seal in a form-fit manner by rotation of the rotary piston and the shaft shoulder is then rigidly connected to the drive shaft.