An inter-stage coupling for a multi-stage vacuum booster pump may include a first coupling face configured to be received by a first adjacent stage of the multi-stage vacuum pump; a second coupling face configured to be received by a second adjacent stage of the multi-stage vacuum pump; and a recirculator comprising a recirculation inlet aperture formed in the first coupling face, a recirculation outlet aperture formed in the first coupling face, and a recirculation conduit having a recirculation valve configured to selectively fluidly couple the recirculation inlet aperture with the recirculation outlet aperture. In this way, the pressure in a stage can be relieved by fluidly coupling the outlet aperture with the inlet aperture in order to recirculate built-up gas from one part of the first stage pump to another part of the first stage pump in order to reduce the strain on the rotor.

The present invention relates to a redundant vacuum pumping system (300) and a pumping method using this system, comprising a primary roots pump (302), a first pumping sub-system (310) and a second pumping sub-system (320), wherein the first pumping sub-system (310) and the second pumping sub-system (320) are arranged to pump in parallel the gas evacuated by the primary roots pump (302), the first pumping sub-system (310) comprising a first secondary roots pump (311) and a first positive displacement pump (312) and a first valve (313) positioned between the gas discharge outlet (302b) of the primary roots pump (302) and the gas suction inlet (311a) of the first secondary roots pump (311), and the second pumping sub-system (320) comprising a second secondary roots pump (311) and a second positive displacement pump (312) and a second valve (323) positioned between the gas discharge outlet (302b) of the primary roots pump (302) and the gas suction inlet (321a) of the second secondary roots pump (321). According to the invention, the first pumping sub-system (310) and the second pumping sub-system (320) are configured to pump at a same flow rate, and the primary roots pump (302) is configured to be able to pump at a flow rate F equal to the pumping flow rate of the primary pumping sub-system (310) plus the pumping flow rate of the secondary pumping sub-system (320).

The present invention relates to a device (1, 30) for the recirculation of an at least partially gaseous composition containing hydrogen, wherein the device (1, 30) is a dry rotary pump comprising a first rotating shaft (13) and a second rotating shaft (14) driving respectively a first piston with claws (8) and a second piston with claws (9) in rotation in a pumping chamber (2) comprising an inlet orifice (11) and an outlet orifice (10) for the gaseous composition, the first rotating shaft (13) and the second rotating shaft (14) being configured to be driven in rotation by a drive system (17,18) situated in a gear chamber (4), wherein the device (1, 30) comprises a first pair of seals (19) and a second pair of seals (20), each comprising a first shaft seal (19a, 20a) and a second shaft seal (19b, 20b), the first pair of seals (19) being provided around the first rotating shaft (13) and the second pair of seals (20) being provided around the second rotating shaft (14) between the pumping chamber (2) and the gear chamber (4), wherein the device (1, 30) comprises a pressure equalization chamber (25) which is in fluid connection with a gap (24) present between the first shaft seal (19a, 20a) and the second shaft seal (19b, 20b) of the first and of the second pair of seals (19, 20) to regulate the pressure in the gap (24), wherein the gear chamber (4) is in fluid connection with the gap (24), and wherein the pumping chamber (2) is in fluid connection with the first shaft seal (19a) of the first pair of seals (19) and with the first shaft seal (20a) of the second pair of seals (20) by means of a pulsation attenuation chamber (22). The present invention also relates to a fuel cell system (40, 50, 60, 70, 80, 90) comprising a device for recirculation according to the present invention.

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.

A vacuum pump cooler for cooling a pumped fluid in a multistage vacuum pump, the vacuum pump cooler comprising: a plate comprising: a first surface; a second surface opposite to the first surface; and a channel through which a cooling fluid can flow; and one or more fins extending from the second surface of the plate.

Aspects of the present invention relate to a stator component for a pump housing. The stator component has a plurality of fluid inlet channels for conveying fluid to respective pumping chambers. The fluid inlet channels each have an inlet port for conveying fluid into the pumping chamber. A plurality of fluid transfer channels are provided for conveying fluid to a respective one of the fluid inlet channels. The fluid transfer channels each have an inlet for receiving pumped fluid. The stator component is adapted to receive at least one sealing member for inhibiting the conveyance of fluid into an associated one of the pumping chambers. Aspects of the present invention relate to a pump housing, a cover plate and a pump. Aspects of the present invention also relate to a method of converting a stator component.

A leak detector is provided for leak-testing objects that are to be tested by spraying tracer gas, the leak detector including: a detection inlet configured to be connected to an object that is to be tested; a pumping device including a vacuum line connected to the detection inlet, a rough-vacuum pump connected to the vacuum line, and a turbomolecular vacuum pump connected to the vacuum line, a delivery of which is connected to the rough-vacuum pump; and a gas detector connected to the turbomolecular vacuum pump, the pumping device further including an ancillary pump connected to the rough-vacuum pump and being configured to lower an ultimate-vacuum pressure of tracer gas in the rough-vacuum pump. A leak detection method for leak-testing objects that are to be tested by spraying tracer gas is also provided.

A sensor assembly for use in an apparatus comprising at least one moving part and at least one stationary part is provided. The assembly comprises a probe and means for mounting the sensor to a stationary part of the apparatus. The probe comprises a portion of an incomplete circuit which, when completed, produces a signal. In use, when the probe is engaged by a moving part of the apparatus, a signal is produced. A vacuum pump or a compressor pump comprising the sensor and a method for preventing failure of an apparatus are also provided.

An object of the present invention is to provide a dry pump and an exhaust gas treatment method which can improve an effect of inhibiting a reaction product from adhering to the inside of a gas outlet port of the dry pump, a gas exhaust pipe, or the like and can also improve an energy saving effect. To attain the object, the present invention includes the gas exhaust pipe disposed to be connected to the gas outlet port of the dry pump and to a gas inlet port of a detoxification device, and a heat exchanger which heats a diluent gas introduced therein using a heat generated from the dry pump and introduces the heated diluent gas into the gas exhaust pipe to heat a used gas to a temperature of not less than a predetermined value.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.