The application relates to a positive displacement pump shaft bearing assembly that comprises a shaft having a shaft lodging and a shaft rotational axis. The assembly further comprises a housing having a housing lodging and one rolling element that is located between said lodgings. The rolling element comprises a rolling element centre point that coincides with the shaft rotational axis.

The application relates to a positive displacement pump shaft bearing assembly that comprises a shaft having a shaft lodging and a shaft rotational axis. The assembly further comprises a housing having a housing lodging and one rolling element that is located between said lodgings. The rolling element comprises a rolling element centre point that coincides with the shaft rotational axis.

An apparatus and a system for application of pressure to a fluid, as well as a corresponding use. The apparatus includes an introduction port for introducing the fluid into the apparatus; a cooling apparatus port and an outlet port; a controllable first valve device having an adjustable first opening pressure value; a second valve device having a second opening pressure value; a controllable third valve device having an adjustable third opening pressure value; the first valve device and the third valve device being automatically controllable for simultaneous application to the fluid of the first predefinable pressure value for output at the outlet port and of the second predefinable pressure value for output at the cooling apparatus port.

The invention relates to a rotary lobe pump including a pump housing with a pump chamber, an inlet opening and an outlet opening. A first multi-lobed rotary piston is rotably mounted around a first axis in the pump chamber. A second multi-lobed rotary piston is rotably mounted around a second axis in the pump chamber and meshes with the first rotary piston. The first and second rotary pistons are rotated by a drive unit to create a fluid flow from the inlet opening to the outlet opening. The drive unit includes a first electric drive motor mechanically coupled with the first rotary piston and a second electric drive motor mechanically coupled with the second rotary piston.

The invention relates to a rotary lobe pump including a pump housing with a pump chamber, an inlet opening and an outlet opening. A first multi-lobed rotary piston is rotably mounted around a first axis in the pump chamber. A second multi-lobed rotary piston is rotably mounted around a second axis in the pump chamber and meshes with the first rotary piston. The first and second rotary pistons are rotated by a drive unit to create a fluid flow from the inlet opening to the outlet opening. The drive unit includes a first electric drive motor mechanically coupled with the first rotary piston and a second electric drive motor mechanically coupled with the second rotary piston.

A method of machining, with a formed tool, a first rotor and a second rotor with mutually complementary meshing threads involves rotating a first workpiece about a longitudinal axis of the workpiece. The tool makes one or more passes along the longitudinal axis of the workpiece as the workpiece rotates so as to remove material, thereby forming the flanks of each helix of the first rotor's thread. The value of at least one of the parameters that collectively define the relative position and relative movement of the workpiece and formed tool is varied during each pass so as to vary the lead of the thread. The above steps are repeated for a second workpiece, thereby forming the second rotor. Adjustments are made to at least one of said parameters during one or more of the passes in order to maintain mutually complementary shapes of the threads of the rotors.

A method of machining, with a formed tool, a first rotor and a second rotor with mutually complementary meshing threads involves rotating a first workpiece about a longitudinal axis of the workpiece. The tool makes one or more passes along the longitudinal axis of the workpiece as the workpiece rotates so as to remove material, thereby forming the flanks of each helix of the first rotor's thread. The value of at least one of the parameters that collectively define the relative position and relative movement of the workpiece and formed tool is varied during each pass so as to vary the lead of the thread. The above steps are repeated for a second workpiece, thereby forming the second rotor. Adjustments are made to at least one of said parameters during one or more of the passes in order to maintain mutually complementary shapes of the threads of the rotors.

A gas compressor includes at least two first and second discharge ports (45a, 45b) which are provided at an upstream side in a rotation direction of a rotor (50) along a peripheral direction of an inner peripheral surface 40a of a cylinder (40) with respect to a closest area (proximity part (48)) where the inner peripheral surface (40a) of the cylinder (40) and an outer peripheral surface (50a) of the rotor (50) are closest in a range of one revolution of a rotation shaft (51) and configured to discharge the refrigerant gas compressed in compression chambers (43). Of the first and second discharge ports (45a, 45b), on only the first discharge port (45a) closest to the proximity part (48), a cutout groove portion (47) is provided at a downstream-side edge portion of the first discharge port (45a) in the rotation direction of the rotor (50).

A gas compressor includes at least two first and second discharge ports (45a, 45b) which are provided at an upstream side in a rotation direction of a rotor (50) along a peripheral direction of an inner peripheral surface 40a of a cylinder (40) with respect to a closest area (proximity part (48)) where the inner peripheral surface (40a) of the cylinder (40) and an outer peripheral surface (50a) of the rotor (50) are closest in a range of one revolution of a rotation shaft (51) and configured to discharge the refrigerant gas compressed in compression chambers (43). Of the first and second discharge ports (45a, 45b), on only the first discharge port (45a) closest to the proximity part (48), a cutout groove portion (47) is provided at a downstream-side edge portion of the first discharge port (45a) in the rotation direction of the rotor (50).

A closing cover integrally includes a cover main body, and a ventilation cap body. The ventilation cap body has a connecting portion that is integrally connected to the cover main body, and at least one ventilation passage hole that is disposed in the connecting portion to perpendicularly extend, and has a depth smaller than a plate thickness of the cover main body. A ventilation recessed portion is formed at a location that is positioned on an inner surface of the ventilation cap body of the closing cover. An inner wall surface defining the ventilation recessed portion is formed in such a shape that a deep side of the ventilation passage hole is opened to the inner wall surface defining the ventilation recessed portion to form a ventilation passage. A ventilation filter is installed on an inner opening portion of the ventilation recessed portion.