A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that-introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, a pressure reducing element disposed between the refrigerant pipes, an accumulator disposed between the refrigerant pipes at a downstream side of the pressure reducing element and at an upstream side of the high-stage compressor, and an oil discharge pipe. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on a downstream side of the pressure reducing element and an upstream side of the accumulator.

A compressor includes three suction pipes. A first center of a first suction pipe, a second center of a second suction pipe, and a third center of a third suction pipe are positioned at vertices of a triangle. A first distance between the first center and a center of a compressor main body is smaller than a second distance between the second center and the center of the compressor main body and a third distance between the third center and the center of the compressor main body. A second flow path cross section and a third flow path cross section are positioned on opposite sides of a center connection line sandwiched therebetween. The first suction pipe is connected to a suction port which is at an uppermost position among three suction ports provided in a case.

A compressor liquid accumulator and a compressor are provided. The compressor liquid accumulator has a first suction cup and a second suction cup. The surface of the first suction cup, which faces the second suction cup, is provided with a first welding surface. The facing of the second suction cup, which faces the first suction cup, is provided with a second welding surface. The first welding surface and the second welding surface are connected in a welded manner. The first suction cup and the second suction cup define a cavity. The first suction cup is provided with a first extending portion is adjacent to the first welding surface. The first extending portion is located in a part of the cavity defined by the second suction cup.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, and an oil return pipe that returns the oil discharged by the high-stage compressor or the oil in the high-stage compressor to the low-stage compressor. The low-stage compressor has a rotary compression part that compresses the refrigerant, a motor that drives the compression part, and a container housing the compression part and the motor. The motor is disposed above the compression part. The oil return pipe is connected to a space below the motor inside the container.

A compressor of an embodiment includes three suction pipes. A first center of a first suction pipe, a second center of a second suction pipe, and a third center of a third suction pipe are positioned at vertices of a triangle. A first distance between the first center and a center of a compressor main body is smaller than a second distance between the second center and the center of the compressor main body and a third distance between the third center and the center of the compressor main body. The first suction pipe is connected to a first suction port on an uppermost side. A second virtual plane on which a central axis of a main curved pipe part of the second suction pipe is disposed and a third virtual plane on which a central axis of a main curved pipe part of the third suction pipe is disposed are inclined to opposite sides from each other with respect to a first virtual plane on which a central axis of a main curved pipe part of the first suction pipe is disposed.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that-introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, a pressure reducing element disposed between the refrigerant pipes, an accumulator disposed between the refrigerant pipes at a downstream side of the pressure reducing element and at an upstream side of the high-stage compressor, and an oil discharge pipe. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on a downstream side of the pressure reducing element and an upstream side of the accumulator.

A high side compressor system includes a compressor housing, motor, and a compression chamber. The compression chamber is disposed within the compressor housing. An accumulator is fluidly coupled to the compressor housing via a pressure-equalization tube. A pressure-equalization valve is disposed in the pressure-equalization tube. The pressure-equalization valve closes access to the pressure-equalization tube responsive to an electrical current being applied to the pressure-equalization valve. The pressure-equalization valve is electrically coupled to a compression mechanism such that interruption of electrical current to the compression mechanism interrupts electrical current to the pressure-equalization valve thereby opening the pressure-equalization valve.

According to one embodiment, a rotary shaft of a rotary compressor includes a first connection shaft and a second connection shaft. The first connection shaft has a cross-sectional shape including a first outer surface, a second outer surface, and a third outer surface. L1 represents a distance from an intersecting point located on one end side where the first outer surface and the second outer surface intersect each other to the rotation center, L2 represents a distance from an intersecting point located on an other end side where the first outer surface and the second outer surface intersect each other, to the rotation center, and L3 represents a distance from the third outer surface to the rotation center, a relationship of L1>L3L2 is satisfied.

Disclosed are: an accumulator fixing device for a compressor, the device being capable of minimizing the generation of vibration and noise; and an air-conditioning apparatus including the same. The disclosed accumulator fixing device comprises: fixing members fixedly provided to an outer side of a compressor; a first supporting member fixing a portion of the accumulator together with the fixing member while encompassing the circumference thereof; and a second supporting member fixing another portion of the accumulator together with the fixing member while encompassing the same, wherein the first supporting member and the second supporting member are arranged to be spaced from each other by a preset gap.

In embodiments, a compressor includes three suction pipes. A first center of a first suction pipe, a second center of a second suction pipe, and a third center of a third suction pipe are positioned at vertices of a triangle. A first distance between the first center and a center of a compressor main body is smaller than a second distance between the second center and the center of the compressor main body and a third distance between the third center and the center of the compressor main body. A first flow path cross section of the first suction pipe overlaps a center connection line passing through the center of the compressor main body and a center of an accumulator. A second flow path cross section and a third flow path cross section are positioned on opposite sides of the center connection line sandwiched therebetween. The first suction pipe is connected to a suction port which is at an uppermost position among three suction ports provided in a case.