An exemplary embodiment of the present disclosure provides an intake device including: an annular flow path which is formed in a circular housing; an inlet part which is installed at one side of the housing and guides an inflow of a fluid into the flow path; a outlet part which is installed at the other side of the housing and guides a discharge of the fluid which flows into the inlet part and passes through the flow path; a piston which is disposed in the flow path, and rotates along the flow path so as to compress the fluid introduced through the inlet part; and an opening and closing unit which is installed in the flow path between the inlet part and the outlet part, includes a plurality of opening and closing members, and elastic members which are installed between the plurality of opening and closing members and the flow path so as to support the plurality of opening and closing members, respectively, and opens and closes the flow path by pressing the piston, in which when the pressing of the piston is released, the plurality of opening and closing members closes the flow path by pressing force of the fluid which presses outer circumferential surfaces of the plurality of opening and closing members in a direction in which the flow path is closed, and by elastic force of the elastic member.

A scroll compressor is provided that may include a casing including a rotational shaft, a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space, a first scroll that is revolved by rotation of the rotational shaft, a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers, a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole, a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, and an elastic member disposed between the floating plate and the discharge cover to provide an elastic force to the floating plate.

A multi-stage expansion device having bypass capabilities and a variable speed drive is disclosed. In one example, the multi-stage expansion device has a housing within which a first stage, a second stage, and a third stage are housed. The housing may also be configured with internal working fluid passageways to direct a working fluid from the first stage to the second stage and/or from the second stage to the third stage. Each of the stages may include a pair of non-contacting rotors that are mechanically connected to each other and to a power output device such that energy extracted from the working fluid is converted to mechanical work at the output device. In one example, a bypass line is provided to bypass working fluid around the first stage and a bypass line is provided to bypass working fluid around the second stage.

Scroll expander including a bypass passage and a bypass valve configured to open and close the bypass passage without significantly increasing the length in the shaft direction of the scroll expander. Scroll expander 23 includes suction port 513 which allows a high-pressure flow of a working fluid to enter and guides the entering flow of the working fluid into an expansion chamber. Discharge port 523 allows the working fluid expanded to a lower pressure in the expansion chamber to flow out. Bypass passage 27 communicates suction port 513 with the discharge port 523 while bypassing the expansion chamber. Bypass valve 28 is configured to open and close bypass passage 27. Suction port 513, bypass passage 27 and a bypass valve attaching portion 514 for attaching the bypass valve 28 are formed in a base plate of the fixed scroll 51.

Scroll expander including a bypass passage and a bypass valve configured to open and close the bypass passage without significantly increasing the length in the shaft direction of the scroll expander. Scroll expander 23 includes suction port 513 which allows a high-pressure flow of a working fluid to enter and guides the entering flow of the working fluid into an expansion chamber. Discharge port 523 allows the working fluid expanded to a lower pressure in the expansion chamber to flow out. Bypass passage 27 communicates suction port 513 with the discharge port 523 while bypassing the expansion chamber. Bypass valve 28 is configured to open and close bypass passage 27. Suction port 513, bypass passage 27 and a bypass valve attaching portion 514 for attaching the bypass valve 28 are formed in a base plate of the fixed scroll 51.

An exemplary embodiment of the present disclosure provides an intake device including: an annular flow path which is formed in a circular housing; an inlet part which is installed at one side of the housing and guides an inflow of a fluid into the flow path; a outlet part which is installed at the other side of the housing and guides a discharge of the fluid which flows into the inlet part and passes through the flow path; a piston which is disposed in the flow path, and rotates along the flow path so as to compress the fluid introduced through the inlet part; and an opening and closing unit which is installed in the flow path between the inlet part and the outlet part, includes a plurality of opening and closing members, and elastic members which are installed between the plurality of opening and closing members and the flow path so as to support the plurality of opening and closing members, respectively, and opens and closes the flow path by pressing the piston, in which when the pressing of the piston is released, the plurality of opening and closing members closes the flow path by pressing force of the fluid which presses outer circumferential surfaces of the plurality of opening and closing members in a direction in which the flow path is closed, and by elastic force of the elastic member.