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.

A shunt pulsation trap for a positive-displacement gas-transfer machine having a gas transfer chamber with an intake port and a discharge port and having at least one positive-displacement drive device (such as two cooperating rotors) defining a compression region of the transfer chamber. The trap includes a pulsation-trap chamber arranged for parallel fluid flow with the machine transfer chamber. The trap has a first (e.g., inlet) port in communication with the compression region of the transfer chamber (e.g., at least one lobe span away or totally isolated from the transfer-chamber intake port), a second (e.g., discharge) port in communication with the discharge port of the transfer chamber, and at least one pulsation dampener in the pulsation-trap chamber. In this way, the shunt pulsation trap traps and attenuates gas pulsations before discharge from the machinery transfer chamber, thereby reducing induced NVH and improving machinery efficiency.

A supercharger includes a main housing, a front cover coupled to the main housing and having an inner portion received within the main housing, a drive coupling assembly arranged between an input shaft and a rotor shaft, and a coupling sleeve disposed about the drive coupling.

A rotor for a multi-stage vacuum pump, a multi-stage vacuum pump and a method. The rotor comprises: a plurality of rotary vanes, the plurality of rotary vanes being axially displaced and coaxially aligned; a pair of end shafts, each end shaft extending from opposing axial ends of the plurality of rotary vanes; and an inter-vane shaft extending between adjacent rotary vanes of the plurality of rotary vanes, the inter-vane shaft having a diameter which is greater than that of the end shafts. In this way, the inter-vane shaft provided between each rotary vane may have an increased diameter, which improves the stiffness of the shaft and changes the modal frequency of the rotor. Such a change in the modal frequency is typically sufficient to improve its operation.

A segmented rotor assembly built from individual rotor segments is presented. In one aspect, the segmented rotor assembly is defined by a plurality of lobes extending between a first lobe end and a second lobe end. Each lobe is constructed from a pair of identically shaped lobe segments mated to each other. Each lobe segment is provided with a helical twist extending between a first segment end and a second segment end. The constructed lobes can then be mated to each other to create a wholly formed rotor.

Method for treating outlet air in a pneumatic waste conveying system, in which the outlet air is at least partly the conveying air to be used in waste conveying. In the method in a first phase additional air is brought into the body of conveying air in the partial-vacuum generator of the pneumatic waste conveying system before the output aperture of the partial-vacuum generator, and that in the method in a second phase additional air is brought into the body of outlet air as a consequence of the suction effect brought about by the outlet air in such a way that the outlet air and the additional air mix with each other at least partly. The invention also relates to an apparatus.

A two-stage rotary compressor for gas, in particular air. The compressor comprises a bottom plate and a head enclosing between them two compression stages. The compressor is characterized in that an interconnection device is arranged between the two compression stages, said device being suited to establish a communication “in series” or “in parallel”, to be selected by the manufacturer, between said two compression stages.

A dry vacuum pump is provided, including two shafts, respectively supporting at least one pumping rotor being configured to synchronously rotate in reverse in order to convey a gas to be pumped from an intake of the dry vacuum pump to an outlet; and a synchronous motor configured to rotate one shaft of the two shafts, the synchronous motor including a rotor coupled to the shaft, a first stator with windings arranged around the rotor, and at least one second stator with windings arranged around the rotor, the windings of the stators being configured to be supplied individually or simultaneously in order to adapt a power of the synchronous motor to a pumping load. A method for controlling a synchronous motor of a vacuum pump is also provided.

A pumping installation includes at least one first positive-displacement machine and one second positive-displacement machine, as well as a control module, in which installation a gas is evacuated from an enclosed volume by means of the first positive-displacement machine and/or the second positive-displacement machine. The pumping installation includes at least one control valve controlled by the control module and a pressure sensor for sensing the value of the pressure at the outlet of the first positive-displacement machine and/or a temperature sensor for sensing the value of the temperature at the outlet of the first positive-displacement machine in order to control the flow of gas between the enclosed volume and the outlet of the pumping installation.

A pumping system is provided, including a rough-vacuum pump; a Roots vacuum pump including a pumping stage having a stator inside which two Roots rotors are configured to rotate synchronously in opposite directions to drive a gas to be pumped between an inlet orifice and an outlet orifice; and a pipeline connecting the outlet orifice to an intake of the rough-vacuum pump, a shortest distance between an edge of the outlet orifice and each of the Roots rotors in the pumping stage being less than 3 cm, and the outlet orifice being situated at the end of an upstream tube of the pipeline that passes into the pumping stage.