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 scroll compressor includes fixed and movable scrolls defining a compression chamber, and a crankshaft. The movable scroll at least partially covers a discharge port formed in the fixed scroll to change a communication area that is a portion of a total area of the discharge port that contributes to communication with the compression chamber. First to third rotation angle positions become larger in order. As the crankshaft rotates from the first to second rotation angle position the communication area increases at a first rate. In the first rotation angle position the compression chamber and the discharge port start communicating with each other. The second rotation angle position is a preliminary discharge interval angle. As the crankshaft rotates from the second to third rotation angle position the communication area increases at a second rate. The second rate of increase is greater than the first rate of increase.

A heat exchange system for a surgical instrument includes a valve, a load, and a load conduit extending between the valve and the load. The load conduit delivers fluid from the valve to the load. The heat exchange system also includes an exhaust conduit that directs the fluid away from the valve. A portion of the load conduit is positioned so as to thermally transfer heat to a portion of the exhaust conduit.

A pump and method for pumping a gas are disclosed. The pump comprises a rotor and a stator. At least one of the rotor or stator comprises at least one liquid opening configured for fluid communication with a liquid source. The liquid opening is configured such that in response to a driving force exerted on liquid from the liquid source a stream of liquid is output from the opening, the stream of liquid forming a liquid blade between the rotor and the stator, gas confined by said stator, said rotor and said liquid blade being driven through said pump from a gas inlet towards a gas outlet.

A compressor system includes a screw compressor and a controller. The screw compressor includes a slide valve selectively actuatable between a first position and a second position to facilitate modulating a capacity of the screw compressor between fully-loaded and fully-unloaded. The controller is communicably coupled to the slide valve. The controller is configured to receive a chilled fluid temperature setpoint for a fluid in heat transfer communication with a refrigerant of the refrigeration circuit; receive temperature data indicative of a chilled fluid temperature of the fluid; determine a difference between the chilled fluid temperature and the chilled fluid temperature setpoint; and provide one of a load command and an unload command to the slide valve based the difference between the chilled fluid temperature and the chilled fluid temperature setpoint. According to an embodiment, the controller does not receive feedback from the screw compressor regarding a position of the slide valve.

A scroll compressor includes: a compression mechanism unit 3 that includes a fixed scroll 31 and an orbiting scroll 32; a crank shaft 6 that causes the orbiting scroll 32 to orbit about the fixed scroll 31; a slider 71 that is provided between the orbiting scroll 32 and the crank shaft 6 and that includes tubular portions 711 and 712 and a flange portion 713 projecting from the outer circumferential surface between one end and the other end of the tubular portions 711 and 712; and a balance weight 72 that is fitted to the slider 71 and that includes a ring-like portion 721 having a portion of the inner surface facing the flange portion 713, a weight portion 722 having an inner surface facing the tubular portion 711 or 712 closer to the one end side U than the flange portion 713, and a projection 723 projecting from the inner circumferential surface of the ring-like portion 721 and having an inner surface facing the tubular portion 711 or 712 closer to the other end side L than the flange portion 713.

A scroll compressor includes a casing, a low-pressure space and a compression mechanism. The compression mechanism includes fixed and movable scrolls, a fluid chamber including first and second compression chambers, and an adjustment mechanism. The fluid chamber has different discharge start points between the first and second compression chambers. An oil inflow groove is formed in one sliding surface, and an oil relief passage is formed in the other sliding surface. The oil relief passage includes a communication portion that communicates with the oil inflow groove in a predetermined angular range, lubricating oil flowing from the oil inflow groove into the low-pressure space through the communication portion. The predetermined angular range is from a position between a discharge start point of the first compression chamber and a discharge start point of the second compression chamber to a position after the discharge start of the second compression chamber.

A compressor includes a first throttle portion that receives a refrigerant at an intermediate pressure from an injection pipe of a refrigerant circuit, an enlarged flow path portion that receives the refrigerant from the first throttle portion, a second throttle portion that receives the refrigerant from the enlarged flow path portion, and a compression element. The compression element includes a compression chamber that receives the refrigerant from the second throttle portion. The first throttle portion has a flow path cross-sectional area that is narrower than both a flow path cross-sectional area of the injection pipe and a flow path cross-sectional area of the enlarged flow path portion. The second throttle portion has a flow path cross-sectional area that is narrower than the flow path cross-sectional area of the enlarged flow path portion.

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 compressor includes a compression mechanism that compresses low-pressure refrigerant in a compression chamber into high-pressure refrigerant, and an injection pipe arranged to supply intermediate-pressure refrigerant to the compression chamber. A valve assembly is disposable between the compression chamber and the injection pipe. The valve assembly includes an opening forming member that forms an opening, a valve body and a spring member. The valve body moves in accordance with differences between pressure of the refrigerant supplied from the injection pipe and pressure of the refrigerant in the middle of compression in the compression chamber. The valve body blocks the opening when the valve body has moved from a compression chamber side to an injection pipe side. The spring member is disposed on the injection pipe side of the opening. The spring member applies force in a direction of the injection pipe to the valve body.