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.

A gas treatment device treats, at atmospheric pressure, the gases pumped by at least one rough pumping device. The gas treatment device includes a treatment chamber and at least one discharge pipe to connect a discharge of the at least one rough pumping device to an inlet of the treatment chamber. The gas treatment device further includes at least one auxiliary pumping device to lower the pressure in the at least one discharge pipe, situated less than 1 meter from the inlet of the treatment chamber, such as less than 50 cm.

A rough-vacuum pump of dry type includes a duct formed in the stator and of which an inlet orifice is intended to be connected to at least one source of purge gas and of which at least one outlet orifice communicates with the last pumping stage communicating with the delivery and a device for injecting a heated purge gas including a heating device to at least partly heat the purge gas injected into the duct to a temperature higher than 40° C.

A device is provided for pumping fluid from a wellbore up to surface. The device includes a stator unit, a rotor unit run within the stator unit on a rod string, the rotor unit and the stator unit engaging with one another to form an annular space therebetween for passage of fluid. An upstream check valve on the rod string uphole of the rotor unit is moveable from an open position in which fluid is passable through the annular space, and a closed position in which fluid passage through the annular space is prevented. A hollow rod section extends through the rod string in fluid communication with the annular space both downstream and upstream of the upstream check valve, for entry of fluid into a downhole end of the hollow rod section, passage of fluid upstream therefrom and exit of fluids from an uphole end of the hollow rod section, back into the annular space. A method is further provided for pumping fluid from a wellbore after shutdown.

A vacuum line and method for controlling a vacuum line in which an auxiliary pumping device and a diluent gas injection device are controlled according to a first operating mode in which the pressure prevailing in the discharge pipe is maintained at less than or equal to 20,000 Pa or according to a second operating mode in which the pressure prevailing in the discharge pipe is greater than 20,000 Pa, and the injection of a diluent gas into the stream of the pumped gases is controlled, downstream of an intake of the rough pumping device, such as into the discharge pipe and/or into the rough pumping device and/or into the auxiliary pumping device by the diluent gas injection device in the second operating mode.

A device evacuates a chamber and purifies the gas extracted from said chamber of any foreign substances. The device comprises a dry-condensing vacuum pump having an input connected to the chamber to be evacuated and is suitable for maintaining the input pressure at a constant level at the output despite variable conditions. An intermediate line which connects to the output of the dry-condensing vacuum pump and a liquid ring vacuum pump, the input of which is connected to the intermediate line, are additionally provided. A corresponding method makes it possible to purify the gas of any foreign substances reliably and effectively.

A stator for a helical gear device includes a first section having first helically convoluted chamber with a set of radially inwardly extending lobes and a second section adjacent to the first section. The second section includes a stack of cutter disks. Each cutter disk includes a front surface, a rear surface, an interior surface defining a central opening extending from the front surface to the rear surface, a forward cutting edge, and a rearward cutting edge. The interior surface forms a same number of lobes for the central opening as the set of radially inwardly extending lobes in the first section. Each cutter disk is aligned along a common centerline, and each cutter disk is rotated slightly relative to each other to form a second helically convoluted chamber with a same pitch as the first helically convoluted chamber. The second helically convoluted chamber exposes, to materials passing through, portions of the forward cutting edge or the rearward cutting edge of each cutter disk.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

A roots rotor for removing dust coagulum and droplets comprises a rotor body, which rotates inside the roots pump case. Both ends of the rotor body are sealing surfaces, which are meshed with the inner wall of the roots pump case. The rotor slot scraping cavities are arranged on both sides of the sealing surface. The side of the rotor slot scraping cavity close to the sealing surface is set as the scraper surface, which forms a sharp edge with the sealing surface. A guide surface is arranged on the surface of the rotor body, and the guide surface is located on the side of the rotor slot scraping cavity away from the sealing surface. The utility model overcomes the disadvantages of the prior art, and the attachment can be scraped off and gathered into the rotor slot scraping groove through the action of the scraper surface; and with the rotation of the rotor body, the particles and dust can be easily dropped outside the exhaust port of the pump; thus to achieve to avoid the accumulation of dust, coagulum and other incompressible medium in the process gas on the wall of the pump case.

A device evacuates a chamber and purifies the gas extracted from said chamber of any foreign substances. The device comprises a dry-condensing vacuum pump having an input connected to the chamber to be evacuated and is suitable for maintaining the input pressure at a constant level at the output despite variable conditions. An intermediate line which connects to the output of the dry-condensing vacuum pump and a liquid ring vacuum pump, the input of which is connected to the intermediate line, are additionally provided. A corresponding method makes it possible to purify the gas of any foreign substances reliably and effectively.