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 dry-type primary vacuum pump includes an injection device to distribute a purging gas in the pumping stages. The injection device includes: a first pressure sensor arranged on a common portion of the distributor, a second pressure sensor arranged on each branch of the distributor, and a control unit to generate a pulse width modulation command signal for the control of the regulation valves independently of one another as a function of the pressure measurement differences between the first pressure sensor and the second pressure sensors.

An apparatus for applying a vacuum during a surgical procedure can include a vacuum pump assembly having a port, a first housing, a second housing, a first silencer or tubular magnet and a second silencer. The first housing can define a first cavity receiving the vacuum pump assembly therein. A portion of the first housing can be formed by a portion of the port. The second housing can define a second cavity receiving the first housing therein. A portion of the second housing can be formed by a second portion of the port. The first silencer or tubular magnet can be coupled to the first housing and can have a longitudinal extent along a longitudinal axis. The first silencer or tubular magnet can extend from the first housing within the second cavity. The second silencer can be coupled to the second housing and can have a longitudinal extent along a longitudinal axis. The second silencer can extend from the second housing within second cavity.

The present disclosure provides a product removal apparatus, a treatment system, and a product removal method that can sufficiently remove the products deposited inside a vacuum pump and also suppress corrosion of the base material of the vacuum pump. The product removal apparatus of the present disclosure includes: a sensor for measuring the temperature of the inside of a vacuum pump, the thickness of a film of a product in a flow path in the vacuum pump, or the vibration frequency of the vacuum pump; a gas supplier for supplying a gas containing hydrogen halide, fluorine, chlorine, chlorine trifluoride, or fluorine radicals to the vacuum pump; and a control device. The control device controls the gas supplier so that the supply of the gas to the vacuum pump is stopped depending on a rate of temperature increase calculated from the temperature measured by the sensor, the film thickness, or the vibration frequency.

A pump includes a first housing part defining a first portion of a bore extending within the first housing part and shaped to receive a rotor; and a second housing part defining a second portion of the bore extending within the second housing part and shaped to receive the rotor. The first housing part has a first face abutable against an opposing second face of the second housing part to position the first portion of the bore with the second portion of the bore to receive the rotor. The first portion of the bore has a first circular cross-section portion centered along the first face and the second portion of the bore having a second circular cross-section portion centered, within the second housing part, at a distance from the second face.

The present invention relates to a pumping system to generate a vacuum (SP), comprising a main vacuum pump which is a claw pump (3) having a gas suction inlet (2) connected to a vacuum chamber (1) and a gas discharge outlet (4) leading into a gas evacuation conduit (5) in the direction of a gas exhaust outlet (8) outside the pumping system. The pumping system comprises a non-return valve (6) positioned between the gas discharge outlet (4) and the gas exhaust outlet (8), and an auxiliary vacuum pump (7) connected in parallel to the non-return valve. In a pumping method by means of this pumping system (SP), the main vacuum pump (3) is started up in order to pump the gases contained in the vacuum chamber (1) and to discharge these gases through its gas discharge outlet (4), simultaneously to which the auxiliary vacuum pump (7) is started up. Moreover the auxiliary vacuum pump (7) continues to pump all the while that the main vacuum pump (3) pumps the gases contained in the vacuum chamber (1) and/or all the while that the main vacuum pump (3) maintains a defined pressure in the vacuum chamber (1).

A positive displacement pump has a casing with a central body and two closing lids, the central body being provided with two cylindrical communicating chambers, one suction pipe and one discharge pipe, and two rotors revolvingly mounted in the chambers of the central body and supported by shafts revolvingly mounted in the closing lids. The two rotors include a male rotor having only protuberances, not cavities, and a female rotor having only cavities, not teeth or protuberances.

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.