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 method of operating an exhaust gas recirculation pump for an internal combustion engine including: providing an EGR pump assembly including an electric motor coupled to a roots device having rotors, the EGR pump operably connected to an internal combustion engine; providing an EGR control unit lined to the EGR pump assembly; providing sensors linked to the EGR control unit; determining if a motor speed is within a predetermined target (step SI), wherein when the motor speed is within the predetermined target then; determining if a motor torque is within a predetermined target (step S2) wherein when the motor torque is within the predetermined target then; determining if a motor temperature is within a predetermined target (step S3) wherein when the motor temperature is within the predetermined target then; maintaining operation of the exhaust gas recirculation pump.

The screw compressor includes a first-stage compressor main body and a second-stage compressor main body for compressing fluid with screw rotors, a motor for driving the first-stage compressor main body and the second-stage compressor main body, and a gear box. The gear box is connected to the first-stage compressor main body, the second-stage compressor main body, and the motor; transmits a driving force of the motor to the screw rotors, and includes a first attachment hole for attaching the first-stage compressor main body and a second attachment hole for attaching the second-stage compressor main body; and is provided with an annular rib surrounding both of the first attachment hole and the second attachment hole. In the screw compressor, the vibration of the natural vibration mode which is most burdensome and should be reduced can be efficiently reduced.

A cooling system is configured to operate in one of three modes, a DX mode of operation when outdoor air is too hot or too humid and the cooling system operates as a normal closed circuit system, a hybrid mode of operation when outside temperatures cool down and the cooling system operates as a partial reduced normal closed circuit system and a free cooling system, and a thermosiphon mode of operation when the outside temperature is below a predetermined temperature and the cooling system operates without the normal closed circuit system. The cooling system includes a scroll compressor unit having a main casing, a scroll compressor supported by the main casing, and a refrigerant pump supported by the main casing. The scroll compressor unit is configured to selectively engage the scroll compressor and the refrigerant pump to achieve one of the DX mode, the hybrid mode, and the thermosiphon mode.

A transmission structure of motor connection of roots pump comprises a shaft sleeve, a motor shaft cavity is opened inside the shaft sleeve, and the inner circle of the motor shaft cavity is concentrically meshed with the excircle of the motor shaft; a fixed bolt mounting cavity is opened on the outer surface of the shaft sleeve, a bolt through-hole is opened in the fixed bolt mounting cavity, the shaft sleeve is fixedly connected with the gear seat through a hexagon bolt, and the gear seat and the shaft sleeve rotate synchronously at the same shaft center; a gear is fixedly connected with the gear seat with a bolt, the gear seat is fixed to the pump shaft through a first keyway under the fitting between the first keyway and a first shaft key, and the pump shaft and the motor shaft are coaxially arranged at the center. The utility model overcomes the disadvantages of the prior art, which is convenient to install without wearing parts, not affected by temperature, pressure and external dust; and the structure is simple with compound seal and oil protection function; and when a motor with a motor shaft is selected, only the diameter and keyway of the motor shaft cavity of the part are required to fit the new motor.

A gas ejection apparatus ejects gas using a compressor that compresses the gas by a rotating body inside a cylinder, and includes a detector and a microcomputer. The detector detects a position of the rotating body inside the cylinder based on positions of gears which are coupled to the rotating body. When the microcomputer receives an ejection instruction, the microcomputer controls intake and exhaust of the compressor according to detection results of the detector, and causes the compressor to wait in an intake completion state upon completion of ejection of the gas that was performed in response to the ejection instruction.

The present disclosure relates to a scroll compressor and its lubricating oil supply system. The lubricating oil supply system includes: an oil passage P.sub.1 formed by a core hole extending longitudinally through the crankshaft; an oil pump, whose oil suction port is immersed in the lubricating oil in the oil pool, and the oil outlet is connected to the oil circuit P.sub.1; an oil passage P.sub.3 located in the gap between the upper end surface of the crankshaft and the lower surface of the orbiting scroll; an oil passage P.sub.4 formed by a longitudinal hole in the crankshaft, the longitudinal hole extending downwards from the upper end surface of the crankshaft; an oil passage P.sub.5 formed by a transverse hole in the crankshaft and a gap between the lower edge of the hub of the orbiting scroll and the upper surface of the upper counterweight, the transverse hole extending transversely from the outer peripheral surface of the upper end of the crankshaft to communicate with the longitudinal hole, the opening of the transverse hole on the outer peripheral surface of the upper end of the crankshaft is aligned with the gap between the lower edge of the hub and the upper surface of the upper counterweight; an oil passage P.sub.6 formed by the gap between the outer peripheral surface of the hub and the upright wall of the upper counterweight, and the gap between the outer peripheral surface of the hub and the inner peripheral surface of the center hole of the housing; and an oil passage P.sub.2 formed by an oil return pipe so that the lubricating oil circulates.

A robot suction hand mountable on an industrial robot and configured to hold a workpiece by suction using a suction unit. The robot suction hand includes: a vacuum pump incorporated in the robot suction hand. The vacuum pump has a housing in which an intake port and an exhaust port are formed, and configured to intermittently take in air from the intake port and intermittently discharge air from the exhaust port. The robot suction hand includes a suction path that communicates with the suction unit and the intake port and a first member made of a porous material. The first member covers the exhaust port.

According to one embodiment, a rotary compressor includes a compression mechanism unit. When H is the length of a middle shaft part, Hp is the length of a bearing hole, Dp is the inner diameter of the bearing hole, Dc is the outer diameter of a crank part, Dm is the outer diameter of the middle journal part, C1 is the axial length of a first chamfered part provided to a middle shaft part-side end edge of the crank part, C2 is the axial length of a second chamfered part, C3 is the axial length of a third chamfered part, and C4 is the axial length. of a fourth chamfered part, Dp is larger than Dc and Dm, and the relationships of [Equation 1] HHp, [Equation 2] H>HpC1C2{square root over ((Dp.sup.2Dc.sup.2))}, and [Equation 2] H>HpC3C4{square root over ((Dp.sup.2Dm.sup.2))} are all satisfied.

A method for decoupling a liquid ring pump component from a liquid ring pump for facilitating maintenance services, the liquid ring pump comprising a housing defining an annular chamber and a shaft passing into the chamber, the component being disposed around the shaft and coupled between the shaft and the housing, the method comprising: coupling, using a first fixing member, a first end of the shaft to the housing thereby to prevent or oppose movement of the shaft relative to the housing in at least a radial direction; and, thereafter, sliding the component along the shaft in a direction along the shaft from the housing towards the first end of the shaft, thereby spacing apart the housing and the component.