A screw compressor has a slide valve movement mechanism having a cylinder provided in a casing body, a piston partitioning an interior of the cylinder into a first chamber and a second chamber, and a communication flow passage through which the second chamber communicates with a low-pressure space. The cylinder is provided with a first inflow hole, a second inflow hole, and a third inflow hole, the first chamber communicating with a high-pressure space through the first inflow hole, the second chamber communicating with the low-pressure space through the second inflow hole and the communication flow passage, the second chamber communicating with the high-pressure space through the third inflow hole. The third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position at which the piston moves toward the second chamber and stops.

A screw compressor has a slide valve movement mechanism that includes a cylinder provided in a casing body, a piston partitioning an interior of the cylinder into a first chamber and a second chamber, and a communication flow passage through which the second chamber communicates with a low-pressure space. The cylinder includes a first inflow hole, a second inflow hole, and a third inflow hole. The first chamber communicates with a high-pressure space through the first inflow hole, the second chamber communicates with the low-pressure space through the second inflow hole and the communication flow passage, and the second chamber communicates with the high-pressure space through the third inflow hole. The third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position at which the piston moves toward the second chamber and stops.

A driving structure of a three-axis multi-stage Roots pump comprises a pump body, wherein a gear end cover is mounted at one side of the pump body, an air outlet end moving bearing air sealing unit is mounted on the other side of the pump body, and the bearing end cover is mounted on the pump at the side of the pump body; a driving axis, a first driven axis and a second driven axis are further provided inside the pump body, and the driving axis is connected with the first driven axis and the second driven axis through the gear, respectively; and both ends of the driving axis, the first driven axis and the second driven axis are movably connected to an air inlet end gear mechanical seal driving unit and an air outlet end moving bearing air sealing unit, respectively. The present invention overcomes the deficiencies of the prior art, a fixed bearing limiting unit not only plays a radial supporting role, strengthens the rigidity of an independent axis, but also reduces the diameter of the axis, and at the same time, evenly distributes to the two axial ends in the axial deformation process, avoiding deformation in a single direction, reducing the amount of displacement by nearly half, and also improving the sealing efficiency of the system.

A fluid machine includes a first rotor having a first rotor first working portion and a first rotor second working portion, a second rotor having a second rotor first working portion configured to mesh with the first rotor first working portion and a second rotor second working portion configured to mesh with the first rotor second working portion and rotate independently from the second rotor first working portion.

A centrifugal-separation type oil separator includes a cylindrical separator body, and an inflow pipe arranged to introduce a fluid including an oil into the separator body. The inflow pipe includes a curved portion. A peripheral wall of the separator body and the inflow pipe include a common portion common to each other.

This patent discloses thrust vectoring ignition chamber engine. Thrust vectoring ignition chamber used in this engine is an annular cylinder having nozzles mounted in a way such that during fuel suction phase they are sealed and during ignition of fuel they are unsealed so that hot jets of ignited fuel escaping through nozzles cause coupled rotatory motion on the ignition chamber. Engine uses cam operated suitably modified 3-screw compressor for suction and compression of fuel and therefore do not require piston mechanism. Flywheel mounted on extension of ignition chamber functions as output of the engine. Each half rotation of flywheel completes three phases namely fuel/air suction, compression and combustion. Thus this engine fires for every half revolution and therefore can give improved power boost.

A multi-stage rotary piston pump comprising two shafts in a housing, which support multiple rotary pistons. Corresponding rotary pistons form a respective rotary piston pair, wherein multiple rotary piston pairs are provided which form a respective pump stage. Neighboring pump stages are each connected to one another via connection channels. The multi-stage rotary piston pump also comprises a pump inlet that is connected to the first pump stage, as well as a pump outlet that is connected to the last pump stage. The built-in volume ratio is at least 15, so that high pumping capacities of at least 1500 m.sup.3/h can be achieved.

A driving structure of a three-axis multi-stage Roots pump comprises a pump body, wherein a gear end cover is mounted at one side of the pump body, an air outlet end moving bearing air sealing unit is mounted on the other side of the pump body, and the bearing end cover is mounted on the pump at the side of the pump body; a driving axis, a first driven axis and a second driven axis are further provided inside the pump body, and the driving axis is connected with the first driven axis and the second driven axis through the gear, respectively; and both ends of the driving axis, the first driven axis and the second driven axis are movably connected to an air inlet end gear mechanical seal driving unit and an air outlet end moving bearing air sealing unit, respectively. The present invention overcomes the deficiencies of the prior art, a fixed bearing limiting unit not only plays a radial supporting role, strengthens the rigidity of an independent axis, but also reduces the diameter of the axis, and at the same time, evenly distributes to the two axial ends in the axial deformation process, avoiding deformation in a single direction, reducing the amount of displacement by nearly half, and also improving the sealing efficiency of the system.

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.

A screw compressor for a heating, ventilation, and air conditioning (HVAC) system. The screw compressor includes a housing having an inlet end and an outlet end for refrigerant to pass into and out of the housing. A motor is within the housing. A plurality of screw sets are arranged about the motor. The screw sets receive refrigerant entering through the inlet, compress the refrigerant between meshed rotors of the plurality of screw sets, and direct refrigerant out of the housing through the outlet end of the housing.