Disclosed is a pump system for a semiconductor chamber includes a housing having a front chamber and a rear chamber, a roots-type rotor provided to the front chamber of the housing, a screw-type rotor provided to the rear chamber, a shaft member coupled through the roots-type rotor and the screw-type rotor, and a driving motor provided to the outside of the housing in such a way as to be axially connected to the shaft member to provide power for driving the rotors. A fluid pipe is provided to the outside of the housing to connect the front chamber and the rear chamber. The fluid pipe is provided with a heater and/or a cooler to heat or cool the fluid flowing through the fluid pipe.

A system includes a compressor configured to compress a vapor, or a vapor and liquid mixture, and a first rotor of the compressor disposed on a first shaft, where the first rotor includes a first plurality of pockets in a first body portion to form a first semi-hollow internal volume or a plurality of flanks and/or a first plurality of flutes on a first external surface of the first rotor, where the plurality of flanks or the first plurality of flutes comprises a first pitch to form first variable leads.

A compressor design includes a male rotor (10) having one or more helical lobes (12) and a female rotor (14) having one or more helical grooves (16). The male rotor is mounted on a first shaft and the female rotor is mounted on a second shaft. The male rotor is positioned in a first section of a chamber and the female rotor is positioned in a second section of the chamber. Fluid enters the chamber at an inlet, and when the rotors are driven, the lobes of the male rotor fit into the grooves of the female rotor, causing compression and movement of the fluid towards an outlet or discharge end where the compressed fluid is discharged. The configuration of the lobe and groove helix, the lobe and groove profile, and the outer diameter of the rotors can be varied in different combinations to form different rotors.

The invention relates to a rotary piston pump comprising a housing with a housing interior, an inlet opening, and an outlet opening; a first rotary piston which is mounted within the housing interior in a rotational manner about a first rotational axis; and a second rotary piston which is mounted within the housing interior in a rotational manner about a second rotational axis. The first rotary piston and the second rotary piston engage into each other in a region between the first and the second axis and displace liquid. The first rotary piston has a frame assembly which comprises multiple mutually spaced plates and is at least partly filled and enveloped with a polymer material.

In an oil-cooled screw compressor, a tooth crest arc of a fixed width is provided to the tooth crest of a male tooth profile, and simultaneously a tooth bottom arc is provided to the tooth bottom of a female tooth profile. Due to the actions thereof, the operation chamber immediately before disappearing exists only in a bottom half region from a line that connects the centers of the male and female tooth profiles, and the opening area relative to the volume of the operation chamber can be increased. As a result, the discharge of oil becomes smooth and energy loss is reduced.

A positive displacement device that converts energy, namely positive displacement compressors that rotate in a single rotational direction to displace working fluid contained in operating chambers. The device described herein is particularity advantageous for the ability to achieve high compression ratios in combination with high discharge pressure and high volumetric throughput in a single stage.

A method for repairing a worn portion in an inner diameter surface of a bore of a cast iron part is disclosed. The inner diameter surface of the bore may have an original surface geometry prior to wear. The method may comprise forming a crescent-shaped pocket in the inner diameter surface of the bore to remove the worn portion, installing an insert in the crescent-shaped pocket, and post-machining the insert to form a crescent-shaped insert that is flush with the original surface geometry of the bore inner surface diameter.

A motor-driven Roots pump includes a housing, a drive shaft and a driven shaft that have axial lines parallel with each other, and a gear chamber. The housing includes a first partition that has a first defining surface, a second partition having a second defining surface, and a relief recess. An addendum circle of the drive gear and an addendum circle of the driven gear intersect with each other at a first intersection point. A plane that includes both the axial lines is defined as an imaginary plane. The first intersection point is located on a side of the imaginary plane on which the drive gear and the driven gear start meshing with each other. An opening of the relief recess is opposed to the first intersection point and is arranged in a region on a side of the imaginary plane on which the first intersection point is located.

The present disclosure provides a method for modifying performance of a rotor profile by adjusting meshing line segments, including the following steps: step 1, dividing a meshing line of a bilateral profile into eight functional segments; step 2, constructing each functional segment by using a cubic NURBS curve; and step 3, locally adjusting the functional segments of the meshing line by adjusting control points or weight factors of the NURBS curve, and observing corresponding changes of the rotor profile so as to adjust corresponding geometrical parameters. The design means is flexible and convenient, the change of the profile is controlled by adjusting the free curve, and the meshing line is locally adjusted in combination with the corresponding relationship between the meshing line and the rotor profile to observe the corresponding change trends, particularly the changes in leak triangle, contact line length, inter-tooth area and area utilization coefficient, of the male and female rotor profile, so that the design efficiency of the rotor profile of a twin-rotor screw compressor is improved, and the defect in the prior art that the rotor profile cannot be locally modified is avoided.

Volumetric compressor (1) for collection and/or treatment equipment of material in liquid, solid, dusty or muddy form. The compressor (1) comprises an operative chamber (50), defining a suction section and an exhaust section of a first fluid, a first header (61) and a second header (62), which delimit said chamber (50) on opposite parts along a longitudinal axis (101). The compressor further comprises at least two rotors (80, 80) with lobes (81, 81) housed in the chamber (50), each rotor (80, 80) rotating about a rotation axis (108, 108) substantially parallel to said longitudinal axis (101). The lobes of each rotor develop according to a helical profile. Furthermore, each of the headers (61,62) defines at least one injection opening (71, 71,72,72) communicating with a feeding device (150) of a second fluid.