The Boc Group, Inc.

Michael Henry North

Nigel Paul Schofield

David John Goodwin

A scroll compressor which comprises a scroll assembly comprising two scroll walls, and a drive for causing a relative orbiting motion between the scroll walls for compressing fluid on two fluid flow paths between an inlet and an exhaust of the scroll assembly. A first fluid flow path is formed between a wall surfaces of the scroll walls and a second fluid flow path is formed between another facing wall surfaces of the scroll walls. A first ambient clearance Ais selected between the first two facing surfaces, and a second ambient clearance Ais selected between the second two facing surfaces, and where the first and the second ambient clearances are selected independently from each other. Independent selection permits each ambient clearance to be designed according to its own performance requirements, to take into account thermal expansion and manufacturing tolerances.

Scroll compressor

A vacuum pump having a screw mechanism and comprising two externally threaded rotors mounted on respective shafts in a pump body and adapted for counter-rotation therein with intermeshing of the rotor threads with close tolerances between the threads and internal surfaces of the pump body in order that gas may be pumped from a pump inlet to a pump outlet by action of the rotor threads, the root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction from the pump inlet to the pump outlet, and wherein the pitch of the rotor threads decreases in a direction from the pump inlet to the pump outlet.

Vacuum pumps

A screw pump has two parallel shafts mounted in a pump body, each shaft thereon and each rotor has at least one helical vane or thread. When the helical vanes or threads inter mesh causing a fluid to be pumped from an inlet towards an outlet of the pump. The bearings associated with each shaft are being positioned in cavities within the first and second rotors which are sealed at their ends closest to the pump inlet. A thermal shield is provided between the bearing arrangements and the internal cavity surfaces.

Screw pump having a thermal shield

A screw pump provided with a first shaft and spaced therefrom and parallel thereto a second shaft mounted in a pump body. A first rotor is mounted on the first shaft and a second rotor mounted on the second shaft. Each of the first and second rotors having formed on an outer surface thereof one or more one helical vanes or threads intermeshing together so that rotary movement of the shafts will cause a fluid to be pumped. A first bearing arrangement is associated with the first shaft and a second bearing arrangement is associated with the second shaft. A bearing carrier is provided for each bearing arrangement and mounted within the pump body so as to be independent from each other.

Screw pumps

A vacuum pump incorporating a screw mechanism section and comprising two externally threaded rotors mounted on respective shafts in a pump body. The externally threaded rotors are adapted for counter-rotation in a first chamber within the pump body with intermeshing of the rotor threads in order to pump gas from a pump inlet by action of the rotors. The root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction from pump inlet and in which the gas is pumped. The two externally threaded rotors are positioned in the pump body by means of shaft bearings located inside cavities in the rotors. The cavities are sealed at the ends closest to the pump inlet.

A compound vacuum pump incorporating a screw mechanism section. The screw mechanism section comprising two externally threaded rotors mounted on respective shafts in a pump body. The rotors are adapted for counter-rotation in a first chamber within the pump body with intermeshing of the rotor threads to pump gas by action of the rotors. The root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction taken from pump inlet and in which the gas is pumped. The pump additionally incorporates a roots mechanism section comprising two roots-type profile rotors also mounted on the respective shafts and adapted for counter-rotation in a second chamber within the pump body situated at an inlet end of the pump.

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Reigate, United Kingdom

Michael Henry North