In a screw compressor, a lobe of a lobe profile of a female rotor includes: a first contour line defining a leading flank; a second contour line defining a trailing flank; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile, when a first angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, a second angle formed by two line segments linking the second rotation center and both ends of the second contour line, and a third angle formed by two line segments linking the second rotation center and both ends of the third contour line, the third angle is greater on the delivery side in the axial direction, and the first angle is smaller on the delivery side in the axial direction.

In a screw compressor, a lobe of a lobe profile of a female rotor includes: a first contour line defining a leading flank; a second contour line defining a trailing flank; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile, when a first angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, a second angle formed by two line segments linking the second rotation center and both ends of the second contour line, and a third angle formed by two line segments linking the second rotation center and both ends of the third contour line, the third angle is greater on the delivery side in the axial direction, and the first angle is smaller on the delivery side in the axial direction.

The disclosure provides a gear pump rotor assembly that includes a rotor body, a rotor head having a plurality of gear teeth and being connected to the rotor body, at least one connector extending between the rotor body and the rotor head, at least one radial deformation control member that extends into at least one gear tooth of the rotor head and reduces the radial deformation of the rotor head relative to the rotor body when a change in temperature causes radial deformation of the rotor body and rotor head.

A multistage pump body comprises a first pumping chamber (20) and a second pumping chamber (21). A connecting duct (26a) puts an outlet (27) of the first pumping chamber (20) into communication with an inlet (28) of the second pumping chamber (21). A leak-tight conduit (40) is provided for the circulation of a cooling liquid. The connecting duct (26a) is a lateral duct of the multistage pump body. A heat-conducting wall (33) partially delimits the connecting duct (26a) and has an external surface (34) on the outside. At least a portion of the connecting duct (26a) passes between this external surface (34) of the heat-conducting wall (33) and the leak-tight conduit (40).

A multistage pump body comprises a first pumping chamber (20) and a second pumping chamber (21). A connecting duct (26a) puts an outlet (27) of the first pumping chamber (20) into communication with an inlet (28) of the second pumping chamber (21). A leak-tight conduit (40) is provided for the circulation of a cooling liquid. The connecting duct (26a) is a lateral duct of the multistage pump body. A heat-conducting wall (33) partially delimits the connecting duct (26a) and has an external surface (34) on the outside. At least a portion of the connecting duct (26a) passes between this external surface (34) of the heat-conducting wall (33) and the leak-tight conduit (40).

A gas compressor includes a compression mechanism, a separator tank that introduces lubricating oil to be supplied to the compression mechanism and a mixed fluid of a working fluid and lubricating oil discharged from the compression mechanism and separates the lubricating oil. An oil cooler cools the lubricating oil from the separator tank. An oil circulation path supplies cooled lubricating oil to the compression mechanism. The gas compressor includes a suction temperature sensor that detects suction temperature of the working fluid, a discharge pressure sensor that detects discharge pressure of the compressed working fluid, a rotation speed sensor that detects rotation speed of the motor. A lubricating oil state estimation unit estimates the temperature of the lubricating oil based on the detected suction temperature, discharge pressure, and rotation speed of the motor. The lubricating oil state estimation unit uses this result to estimate the deterioration state of the lubricating oil.

A gas compressor includes a compression mechanism, a separator tank that introduces lubricating oil to be supplied to the compression mechanism and a mixed fluid of a working fluid and lubricating oil discharged from the compression mechanism and separates the lubricating oil. An oil cooler cools the lubricating oil from the separator tank. An oil circulation path supplies cooled lubricating oil to the compression mechanism. The gas compressor includes a suction temperature sensor that detects suction temperature of the working fluid, a discharge pressure sensor that detects discharge pressure of the compressed working fluid, a rotation speed sensor that detects rotation speed of the motor. A lubricating oil state estimation unit estimates the temperature of the lubricating oil based on the detected suction temperature, discharge pressure, and rotation speed of the motor. The lubricating oil state estimation unit uses this result to estimate the deterioration state of the lubricating oil.

Exhaust gas recirculation pump (30) for an internal combustion engine that includes an electric motor (32) disposed within a housing (36). A Roots device (38) is coupled to the electric motor (32) and includes a housing (40) defining an internal volume (42) in which rotors (44) are disposed and are connected to the electric motor (32). The electric motor housing (36) includes a coolant path (48) formed therein which extends from a coolant inlet (58) to a coolant outlet (78), both coupled to an engine coolant circulation system. The housing includes an oil path (108) formed therein. The oil path includes an oil inlet (110) extending to at least one oil outlet (112). The oil inlet and outlet are coupled to an engine oil circulation system wherein the oil path (108) lubricates bearings (100) and a transmission assembly (46) of the exhaust gas recirculation pump (30).

Exhaust gas recirculation pump (30) for an internal combustion engine that includes an electric motor (32) disposed within a housing (36). A Roots device (38) is coupled to the electric motor (32) and includes a housing (40) defining an internal volume (42) in which rotors (44) are disposed and are connected to the electric motor (32). The electric motor housing (36) includes a coolant path (48) formed therein which extends from a coolant inlet (58) to a coolant outlet (78), both coupled to an engine coolant circulation system. The housing includes an oil path (108) formed therein. The oil path includes an oil inlet (110) extending to at least one oil outlet (112). The oil inlet and outlet are coupled to an engine oil circulation system wherein the oil path (108) lubricates bearings (100) and a transmission assembly (46) of the exhaust gas recirculation pump (30).

A rotary device includes a first rotor rotatable about a first axis and having at its periphery a recess bounded by a curved surface, and a second rotor counter-rotatable to the first rotor about a second axis, parallel to the first axis, and having a radial lobe bounded by a curved surface, the first and second rotors being coupled for intermeshing rotation, wherein the first and second rotors of each section intermesh in such a manner that on rotation thereof, a transient chamber of variable volume is defined, the transient chamber having a progressively increasing or decreasing volume between the recess and lobe surfaces, the transient chamber being at least in part defined by the surfaces of the lobe and the recess; the ratio of the maximum radius of the lobe rotor and the maximum radius of the recess rotor being greater than 1.