Edwards Limited

Michael Henry North

Neil Turner

Malcolm William Gray

Phillip North

David Alan Turrell

Timothy Charles Draper

Tristan Richard Ghislain Davenne

At least a part of a stator for a vacuum pump, comprising: a plurality of walls defining therebetween at least a part of a pumping chamber; a channel formed within one or more of the walls of the plurality of walls, the channel comprising a first opening at a first end of the channel and a second opening at a second end of the channel, the first opening being an opening in an internal surface of the one or more of the walls and being in fluid communication with the pumping chamber; and a pressure relief valve disposed within the channel.

Stator for a vacuum pump

A twin-shaft pump comprising: a pumping chamber; two rotatable shafts each mounted on bearings is disclosed. Each of the two rotatable shafts comprises at least one rotor element, the rotor elements being within the pumping chamber and the two rotatable shafts extending beyond the pumping chamber to a support member. The support member comprises mounting means for mounting the bearings at a predetermined distance from each other, the predetermined distance defining a distance between the two shafts. A thermal break between the pumping chamber and the support member is provided for impeding thermal conductivity between the pumping chamber and the support member, such that the pumping chamber and support member can be maintained at different temperatures. The support member and the rotor elements are formed of different materials, a coefficient of thermal expansion of a material forming the support member being higher than a coefficient of thermal expansion of a material forming the rotor elements.

Twin-shaft pumps with thermal breaks

A rotor for a multi-stage vacuum pump, a multi-stage vacuum pump and a method. The rotor comprises: a plurality of rotary vanes, the plurality of rotary vanes being axially displaced and coaxially aligned; a pair of end shafts, each end shaft extending from opposing axial ends of the plurality of rotary vanes; and an inter-vane shaft extending between adjacent rotary vanes of the plurality of rotary vanes, the inter-vane shaft having a diameter which is greater than that of the end shafts. In this way, the inter-vane shaft provided between each rotary vane may have an increased diameter, which improves the stiffness of the shaft and changes the modal frequency of the rotor. Such a change in the modal frequency is typically sufficient to improve its operation.

Multi-stage vacuum booster pump rotor

A pump cooling system may include a cooling body configured to be fitted to a pump housing to receive heat from the pump housing via a heat conducting path between the cooling body and pump housing. The cooling body may have a passage through which, in use, a cooling fluid is passed to conduct heat away from the cooling body. The pump cooling system includes a cooling control mechanism configured to provide a gap in the heat conducting path at pump operating temperatures below a predefined temperature so heat conduction from the pump housing to the cooling body is interrupted.

Pump cooling systems

A screw pump includes a stator having a fluid inlet and a fluid outlet, the stator housing first and second externally threaded, tapered rotors mounted on respective shafts and adapted for counter-rotation within the stator to compress fluid passing from the fluid inlet to the fluid outlet, wherein the threads have a pitch that increases towards the fluid outlet.

Screw pump having varying pitches

A rotor for a screw vacuum pump has a threaded body in which a central cavity is formed. A coolant is supplied to the cavity from a supply line provided in a shaft attached to the body. A coolant flow guide, which may be either separate from or at least partially integral with the shaft, is located within the cavity. The flow guide has an outer surface adjacent, preferably in contact with, the body to enable heat to the transferred from the rotor to the guide. The guide also has an inner surface defining a bore, and defines at least in part a plurality of axially extending slots radially spaced from and in fluid communication with the bore. In use, coolant flows into the cavity through the bore of the guide, and out from the cavity through the axially extending slots, extracting heat from the guide as it flows both into and out form the cavity. The discharged coolant is conveyed form the slots into a discharge line located within the shaft.

Growing community of inventors

Redhill, United Kingdom

Michael Henry North