Abstract: A multi-stage vacuum pump may include a sealing arrangement for sealing between the stator components of the pump. The end seals of the arrangement comprise an annular portion for sealing between end stator components and shell components and axial portions which extend from the annular portion and together with separate axial seals seal between the shell components.

Abstract: A method is described for treating a gas stream comprising fluorine (F2) gas. In a preferred embodiment, the method comprises adding water vapor to a gas stream and conveying the gas stream and water vapor to a reaction chamber containing a heated bed of material to react with F2 to form an inorganic fluoride while inhibiting formation of CF4 within the reaction chamber, and at least partially evacuating the reaction chamber so that the gas stream is conveyed to and from the reaction chamber at sub-atmospheric pressure.

Abstract: 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.

Abstract: In order to increase the operable range of a DC plasma torch in an abatement apparatus, the apparatus comprises a power control configured for controlling the power of the plasma torch by selective control of the plasma source gas flow regulator

Abstract: Apparatus and a method are provided for inhibiting the propagation of a flame front that is ignited by a pumping mechanism which draws a waste stream from a process chamber. The apparatus comprises a foreline for conveying the waste stream which is drawn from the process chamber to the pumping mechanism. The foreline comprises an isolation valve for selectively isolating the pumping mechanism from the process chamber and a bypass positioned around the isolation valve. The apparatus further comprises a controller for actuating the isolation valve. The controller is configured to cause the isolation valve to be closed when the waste stream is initially drawn from the process chamber. During which time the waste stream is conveyed to the pumping mechanism via the bypass, the bypass comprises means for inhibiting propagation of a flame front therethrough.

Abstract: The present invention relates to a vacuum pumping system (10) which comprises: a vacuum pumping mechanism (12) and a motor (14) for driving the vacuum pumping mechanism. Means (16) are provided for determining a cumulative load on the vacuum pumping system over time by monitoring a characteristic of the motor over that time. Means (18) are also provided for activating a maintenance activity on the system when the cumulative load exceeds a predetermined amount.

Abstract: A microwave plasma reactor (10) comprises a reactor chamber, a microwave resonant cavity (14) located within the reactor chamber, a waveguide (16) for conveying microwave radiation to the resonant cavity, the waveguide having a convergent tapered portion, means for forming an electromagnetic standing wave within the resonant cavity from the microwave radiation for initiating and sustaining a plasma within the resonant cavity, the resonant cavity having a gas inlet and a gas outlet, and conduit means extending from the gas outlet for containing a plasma conveyed from the resonant cavity with a gas flowing from the gas inlet to the gas outlet.

Abstract: In order to minimize the amount of contaminants that pass through a pump, or that are allowed to accumulate therein, a sub-atmospheric pressure gas scrubber suitable for use upstream of a vacuum pump is provided. The gas scrubber comprising a vessel and means for forming a spray of cleaning solvent within the vessel, the vessel comprising an inlet and an outlet for the gas to be cleaned at sub atmospheric pressure, the inlet and outlet being arranged to cause the gas to be cleaned to pass through the spray of cleaning solvent, the means for forming a spray comprising a cleaning solvent inlet connected to at least one spray nozzle and a cleaning solvent outlet through which used solvent can be pumped from the vessel using a pump, wherein the pump is arranged to recirculate the used solvent back to the cleaning solvent inlet.

Abstract: A differentially pumped vacuum system includes first, second and third chambers, and a pumping arrangement for evacuating the chambers. The pumping arrangement includes a compound pump having a first inlet connected to an outlet from the first chamber, a second inlet connected to an outlet from the second chamber, a first pumping section and a second pumping section downstream from the first pumping section, the sections being arranged such that fluid entering the compound pump from the first inlet passes through the first and second pumping sections and fluid entering the compound pump from the second inlet passes through, of said sections, only the second section. The pumping arrangement further includes a booster pump connected to an outlet from the third chamber, and a backing pump connected to the exhaust from the booster pump. Fluid exhaust from the compound pump can be conveyed to either the booster pump or the backing pump as required.

Abstract: A differentially pumped mass spectrometer system comprises a mass spectrometer having first and second pressure chambers through which, during use, ions are conveyed along a path. A pump assembly for differentially evacuating the chambers is attached to the mass spectrometer. The pump assembly comprises a housing attached to the mass spectrometer and a cartridge inserted into the housing. The cartridge has a plurality of inlets each for receiving fluid from a respective pressure chamber and a pumping mechanism for differentially pumping fluid from the chambers. The cartridge is inserted into the housing such that the pumping mechanism is inclined relative to the ion path, but with the cartridge protruding into the mass spectrometer to such an extent that at least one of the inlets at least partially protrudes into its respective chamber without crossing the ion path.

Abstract: A pumping system includes a pumping mechanism, a motor for driving the pumping mechanism, a device for supplying power of a variable frequency to the motor, a control device for setting a maximum value for a current in the motor, and a device for supplying to the control device data indicative of the temperature of gas exhaust from the pumping mechanism and a temperature of the stator of the pumping mechanism, wherein the control device is configured to use the received data to adjust the maximum value during operation of the pumping system.

Abstract: In some examples, a scroll pump 10 may include two scrolls, which are co-operable for pumping fluid from an inlet to an outlet on relative orbiting motion of the scrolls. Each scroll may include a respective scroll base from which a respective scroll wall extends generally axially towards the base of the opposing scroll. At least a first portion of one or each of the respective scroll walls has formed in an axial end face thereof a plurality of pockets distributed along the first portion for disrupting leakage of fluid from a high pressure side of the scroll wall to a low pressure side of the scroll wall.

Abstract: The present invention relates to a scroll pump with two scrolls that are co-operable for pumping fluid from an inlet to an outlet on relative orbiting motion of the scrolls. Each scroll comprises a scroll base from which a scroll wall extends generally axially towards the base of the opposing scroll. A gas conduit having an inlet at a first location of the pumping channel and an outlet at a second location of the pumping channel allows over-compression at the first location of the pumping channel to be exhausted to the second location of the pumping channel. A one-way valve located in the gas conduit allows the passage of gas through the conduit from the conduit inlet to the conduit outlet when a predetermined pressure differential between the first and second locations of the pumping channel is generated during roughing when the scroll inlet is at or close to atmosphere.

Abstract: First and second pump stages provide a flow-path from an inlet to the outlet (30), the flow-path being arranged so that molecules entering the first inlet (26) pass to the outlet through the first (120) and second (122) pump stage, and so that molecules entering the second inlet (28) pass to the outlet through an inter-stage volume (121) and second pump stage (122); wherein the first (120) and second (122) pump stages each comprise a turbo-molecular sub-stage (120a, 122a) and a molecular drag sub-stage (120b, 122b).

Abstract: A vacuum pumping arrangement comprises a turbomolecular pumping mechanism and a molecular drag pumping mechanism connected in series. A rotor of the molecular drag pumping mechanism is supported by the rotor blades of the turbomolecular pumping mechanism.

Abstract: A method and apparatus for reducing undesirable noise generated by a vacuum pumping system. The vacuum system operates to reduce the pressure in a chamber to a first pressure value. The system then detects that the pressure at the vacuum pump system's inlet is about to change to a second higher pressure and, in response, the speed of a booster pump in the vacuum pump system is reduced below the rated speed for the pump. When the pressure at the vacuum pump's inlet is above the second pressure, the speed of the booster pump is increased to the rated speed. Thus, the booster pump is slowed down prior the pump system becoming exposed to a rapid increase in inlet pressure.

Abstract: The invention provides a mass spectrometer system (10) comprising a mass spectrometer (12) comprising a plurality of mass spectrometer stages (16, 18, 20, 44) in fluid communication from a low vacuum stage (16) to a higher vacuum stage (44). A split flow multi-stage pump (14) evacuates the mass spectrometer stages. The pump comprises a pump envelope (28) in which a plurality of pumping stages (20, 32, 34) are supported for rotation about an axis X generally parallel to the direction of flow in the mass spectrometer stages for pumping fluid from a main pump inlet (36) to a main pump outlet (38). At least part of a higher vacuum stage (44) is located within the pump envelope at the main pump inlet.

Abstract: A multistage vacuum pump includes a stator housing a multistage rotor assembly, each stage having intermeshing Roots rotor components, wherein the tip radius of the rotor components at an inlet stage of the pump is larger than the tip radius of the rotor components at an exhaust stage of the pump, wherein a meshing clearance between the rotor components at the inlet stage of the pump is greater than a meshing clearance between the rotor components at the exhaust stage of the pump.

Abstract: Combined booster and primary pump arrangements can be bulky and require separate supplies of purge gas and cooling water. In order to overcome this problem invention provides a vacuum pump in which two or more pumping mechanisms, i.e. the booster pump and main pump, are housed in the same stator. The invention further provides a vacuum pump stator comprising at least two operatively interconnected cavities, wherein at least two of the cavities each comprise at least one rotor-receiving portion shaped to receive two or more at least partially intermeshing rotors, and wherein an axis of a rotor-receiving portion of a first one of the cavities is offset with respect to an axis of a rotor-receiving portion of a second one of the cavities.

Abstract: Apparatus is described for treating an effluent gas stream from a semiconductor manufacturing process tool. The apparatus comprises a plasma torch for generating a glow discharge from an inert, ionisable gas. The gas stream is conveyed to the glow discharge to ignite a plasma. A source of electromagnetic radiation supplies electromagnetic radiation to the effluent gas stream to sustain the plasma. The apparatus is particularly suitable for treating perfluorinated and hydroflurocarbon compounds in the effluent gas stream.