JP4883028B2 - Expansion machine - Google Patents

Description

  The present invention relates to an expander that recovers energy by the expansion force of a high-pressure fluid, and more particularly to a configuration that prevents an overexpansion phenomenon that causes a decrease in energy recovery efficiency.

  For example, as shown in FIG. 8, the conventional expander includes a cylinder 59 having a cylindrical inner space, an eccentric rotor 61 that performs a revolving motion along the inner peripheral wall of the inner space of the cylinder 59, the cylinder 59, and the A vane 63 that reciprocally slides with the revolution of the eccentric rotor 61 is provided between the eccentric rotor 61 and an expansion chamber 62 is formed in the cylindrical internal space of the cylinder 59. Yes.

  The cylinder 59 is provided with an opening / closing valve 69 and an inflow port 64 for introducing a high-pressure fluid into the expansion chamber 62 and an outflow port 65 for deriving the low-pressure fluid that has expanded from the high-pressure state to the outside. They are connected so as to sandwich them. The eccentric rotor 61 is connected to the power recovery shaft 60 via a crankshaft. When the eccentric rotor 61 performs a revolving motion by the expansion of the high-pressure fluid introduced from the inflow port 64, the eccentric rotor 61 is connected to the power recovery shaft 60 via the crankshaft. The power recovery shaft 60 performs a rotational motion, and this rotational power is used for a generator or the like.

  Along with the revolving motion of the eccentric rotor 61, the expansion chamber 62 formed in the internal space of the cylinder 59 is sequentially switched from the portion that was on the expansion side to the discharge side and the portion that was on the discharge side to the expansion side. The angular range of the suction process and the expansion process of the eccentric rotor 61 is set in advance, and the fluid expansion ratio is constant. The high pressure fluid is introduced into the cylinder in the angular range of the suction process, while the fluid is expanded at a set expansion ratio in the angular range of the expansion process, thereby recovering the rotational power. However, in the refrigeration cycle to which the expander is connected, the high-pressure side pressure and the low-pressure side pressure in the refrigeration cycle fluctuate due to the temperature change of the cooling target and the temperature change of the heat dissipation target. The pressure of the discharged refrigerant will also fluctuate. When the actual expansion ratio of the refrigeration cycle becomes larger than the design expansion ratio of the expander due to changes in operating conditions, a state occurs in which the pressure in the expansion chamber becomes lower than the low-pressure side pressure of the refrigeration cycle. An overexpansion phenomenon will occur. When the overexpansion phenomenon occurs, it is necessary to recover the low-pressure side pressure of the refrigeration cycle, and this causes a problem that the energy recovery efficiency in the expander decreases.

  In order to suppress the occurrence of refrigerant overexpansion, for example, as shown in FIG. 8, the outflow port 65 is connected to an intermediate position in the expansion process of the expansion chamber 62, and an on-off valve 67a and a check valve 68 are provided. Further, a technique is proposed in which a bypass passage 67 is provided so that the on-off valve 67a opens and closes according to the differential pressure between the outflow port 65 and the expansion chamber 62. When overexpansion occurs in the expansion chamber 62 and the pressure in the expansion chamber 62 becomes lower than the pressure in the outflow port 65, the on-off valve 67 a is opened, and the refrigerant flows backward from the outflow port 65 to the expansion chamber 62. As a result, the pressure in the expansion chamber 62 is restored to the low pressure side pressure of the refrigerant circuit to suppress the overexpansion phenomenon. There is also a method of connecting the inflow port 64 and the expansion chamber 62 by a communication passage 66 having an opening / closing mechanism 66a (see Patent Document 1).

However, a detection means such as a pressure sensor for detecting a differential pressure between the outflow port 64 and the expansion chamber 62, an on-off valve 67a and a check valve 68, and a control means for appropriately opening and closing the on-off valve 67a are provided. This not only requires a lot of man-hours to manufacture the expander, but also causes an increase in manufacturing cost and, in turn, an increase in manufacturing cost of the refrigeration cycle. Countermeasures were required. Further, the bypass passage 67 becomes a dead volume in the fluid expansion process, which may cause a decrease in expansion efficiency.
JP 2004-190559 A (page 7, FIG. 4)

  In view of the above problems, the present invention accurately eliminates the overexpansion phenomenon with a simple and cost-saving configuration without requiring a pressure sensor, a control means for controlling the pressure sensor, an on-off valve, a check valve, and the like. It aims at providing the expander which can be suppressed.

In order to solve the above problems, the present invention provides a cylinder having an internal space, an upper bearing and a lower bearing sandwiching the upper and lower ends of the cylinder, a crankshaft, and the upper bearing and the lower A shaft pivotally supported by a bearing; a rotor that is loosely fitted to the crankshaft and revolves in the internal space of the cylinder; a vane that defines the internal space; the sealed container and the cylinder; A refrigerant inflow hole through which high-pressure fluid flows in and a refrigerant outflow hole through which low-pressure fluid flows out from the internal space. The high-pressure fluid from the refrigerant inflow hole is expanded in the internal space to cause the rotor to revolve. , In an expander in which the fluid that has been expanded to a low pressure is discharged from the refrigerant outlet hole,
Wherein the upper bearing or the lower bearing, while the one end opening into the inner space and the other end to form the upper communicating groove to overlap on the projection plane as seen from the shaft rotational axis to the refrigerant outlet hole, the cylinder A lower communication groove that is opposed to the upper communication groove and has a communication hole that communicates with the refrigerant outflow hole is formed in the lower communication groove due to a differential pressure between the internal space and the refrigerant outflow hole. It is configured to accommodate a chip seal that operates to open and close the communication hole.

Also, a cylinder having an internal space provided in the sealed container, an upper bearing and a lower bearing that sandwich the upper and lower ends of the cylinder, a shaft that includes a crankshaft and is supported by the upper bearing and the lower bearing, In the internal space of the cylinder that is loosely fitted to the crankshaft, the rotor revolves with one end in contact with the peripheral wall of the internal space, the vane that defines the internal space, the sealed container, and the cylinder, A refrigerant inflow hole through which high pressure fluid flows into the internal space and a refrigerant outflow hole through which low pressure fluid flows out from the internal space. The high pressure fluid from the refrigerant inflow hole is expanded in the internal space to cause the rotor to expand. In an expander that revolves and expands the low-pressure fluid that flows out of the refrigerant outflow hole,
The rotor is provided with a first through hole that is located in the revolving motion direction from the contact point between the rotor and the peripheral wall and is open at one end, and on the rear side of the revolving motion from the contact point between the rotor and the peripheral wall. A second communication hole having one end opened and a groove communicating with the other end of the first communication hole and the other end of the second communication hole on one side of the rotor; The groove is configured to accommodate a tip seal that operates in accordance with a differential pressure between the first series of through holes and the second communication hole.

  Further, at the position where the rotor is driven to revolve toward the refrigerant outflow hole side, the tip seal closes the first communication hole when the pressure of the second communication hole is higher than that of the first communication hole. When the pressure of the second communication hole is lower than that of the first communication hole, the second communication hole and the first communication hole are communicated through a notch provided in the tip seal. It becomes the composition which becomes.

  According to the present invention, the pressure sensor, the control means for controlling the pressure sensor, the on-off valve, the check valve, etc. are not required, and the chip seal made of the resin material is made by the differential pressure between the refrigerant outlet hole side and the low pressure side expansion chamber. By operating, it is possible to provide an expander that can accurately suppress the overexpansion phenomenon with a simple and cost-effective configuration.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the attached drawings.

  FIG. 1 is a refrigerant circuit in which an expander is used, and FIG. 2 is a cross-sectional view of the expander according to the present invention. 3 (A) and 3 (B) are explanatory views schematically showing a cross section of the expander, and FIGS. 4 (A) to 4 (C) are main part cross-sectional views. 5 (A) to 5 (C) are explanatory views showing the operation of the expander, and FIGS. 6 (A) and 6 (B) are explanatory views showing the operation of the bypass path in the first embodiment. is there. FIG. 7 is a sectional view showing a second embodiment.

  The refrigerant circuit 1 including the expander 4 according to the present invention is configured by sequentially connecting a compressor 2, a radiator 3, an expander 4, and a heat absorber 5 as shown in FIG. A carbon dioxide refrigerant as a natural refrigerant circulates in the refrigerant circuit 1. The compressor 2 is composed of a scroll compressor or a rotary compressor, and the radiator 3 and the heat absorber 5 are arranged in parallel with a large number of fins arranged in parallel and the fins. It is comprised with the cross fin type heat exchanger which consists of the meandering-shaped heat exchanger tube made.

  The carbon dioxide refrigerant compressed by the compressor 2 and brought into a supercritical state flows into the radiator 3 and releases heat by the radiator 3. The carbon dioxide refrigerant that has released the heat flows into the expander 4 and expands in the expander 4 to be in a two-phase state composed of a gas phase and a liquid phase. The two-phase carbon dioxide refrigerant absorbs heat by the heat absorber 5 to be in a gas phase state and returns to the compressor 2. The carbon dioxide refrigerant in the expander 4 is configured to rotationally drive a shaft 11 to be described later by the expanding energy, and the rotational power of the shaft 11 is supplied to, for example, a generator connected thereto. It is used to generate electricity. As a result, the expansion energy of the refrigerant is effectively utilized without being discarded.

  As shown in the sectional view of FIG. 2, the expander 4 is made of a thick steel material and has flanges at both ends, and is attached to a cylindrical main case 4b and an upper surface of the main case 4b. An upper cover 4a formed in a dome shape with a flange on the periphery, a lower cover 4c that is attached to the lower surface of the main case 4a, has a flange on the periphery, and has a shaft 11 bearing in the center. The main casing 4b is provided with an expansion mechanism in two upper and lower stages.

  As shown in the cross-sectional view of FIG. 2 and the explanatory diagram of FIG. 3B, the expansion mechanism of the expander 4 includes an upper bearing 6 formed in a mountain shape with a central portion protruding from the bearing, and a circular shape. A first cylinder 9 formed in an annular shape and having an internal space with a circular cross section inside, a cylindrical intermediate plate 7 provided with a bearing, and a second cylinder 10 formed in the same shape as the first cylinder 9. And a lower bearing 8 formed in a shape opposite to the upper bearing 6 in the vertical direction, and a crankshaft 11a is formed by the upper bearing 6, the intermediate plate 7, and the lower bearing 8 at the center thereof. And the shaft 11 provided with the crankshaft 11b in two upper and lower stages is pivotally supported. Further, a lubricating oil supply hole 18 bent in a substantially U shape is formed in the vertical direction at the side of the shaft 11, and the lubricating oil is supplied to the upper bearing 6 by the lubricating oil supply hole 18. And the intermediate plate 7 and the lower bearing 8 are supplied to the bearing.

  As shown in the sectional view of FIG. 3 (A), a thin cylindrical crankshaft 11a that is eccentric from the shaft core of the shaft 11 is formed in the inner space having a circular cross section of the first cylinder 9 and the second cylinder 10. And an annular rotor 12 and a rotor 13 with vanes 12a projecting from the side surfaces thereof slide on the outer peripheral surfaces of the crankshaft 11a and the crankshaft 11b, respectively. Freely fitted.

  The vane 12 a of the rotor 12 is supported so as to be sandwiched between a pair of left and right bushes 20 that are freely fitted in a circular recess of the first cylinder 9 and is supported by the bushes 20. It is free to reciprocate. The bush 20 rotates clockwise or counterclockwise, and the vane 12a reciprocally slides with respect to the bush 20 so that the rotor 12 moves in the inner space of the first cylinder 9 and the crankshaft. While sliding with the outer peripheral surface of 11a, one end of the outer peripheral surface of the rotor 12 is brought into contact with the peripheral wall of the internal space so that revolving motion can be performed. The same applies to the rotor 13. An expansion chamber 19 is formed between the rotor 12 and the peripheral wall of the internal space.

  As shown in the cross-sectional view of FIG. 3A, the main case 4b and the first cylinder 9 are V-shaped so that the refrigerant inlet hole 14 and the refrigerant outlet hole 15 face each other. One end of each of the refrigerant inflow hole 14 and the refrigerant outflow hole 15 is connected to the internal space of the first cylinder 9 so as to sandwich the vane 12a, and the other end is connected to the main case 4b. Are respectively connected to the pipe connectors 14a and 15a provided on the outer peripheral wall. A pipe connector 14a communicating with the refrigerant inflow hole 14 is connected to the radiator 3 side in the refrigerant circuit of FIG. 1, and a pipe connector 15a communicating with the refrigerant outflow hole 15 is connected to the heat absorber 5 side. Connected. An opening / closing valve (not shown) is connected to the refrigerant inflow hole 14 side, and the opening / closing valve is opened within a predetermined angle range of the rotor 12 for sucking the refrigerant into the internal space of the first cylinder 9. It is like that. The configuration of the second cylinder 10 is the same as that of the first cylinder 9.

  As shown by the dotted line in FIG. 3A, the upper bearing 6 and the first cylinder 9 communicate with each other in a rectangular cross section so as to connect the expansion chamber 19 and the refrigerant outflow hole 15 in a curved shape. As shown in the AA sectional view of FIG. 4 (A), the communication portion 21 is provided on the upper communication groove 6a formed on the upper bearing 6 side and on the first cylinder 9 side. The lower communication groove 9a is formed. The lower communication groove 9a is connected to the refrigerant outflow hole 15 formed in the first cylinder 9 by a communication hole 9b formed in the bottom surface, and the communication hole 9a is connected to the lower communication groove 9a. A long chip seal 22 made of a resin material and having elasticity is accommodated so as to close 9b. Further, the lower communication groove 9a is closed on the side of the expansion chamber 19 of the communication hole 21 so that the tip seal 22 does not fall off as shown in the BB cross-sectional view of FIG. FIG. 4C is a schematic diagram of the above configuration, and the upper communication groove 6 a extends to the expansion chamber 19 side and opens the opening 6 b into the expansion chamber 19. The second cylinder 10 side is also formed in the same manner. The communication portion 21 is not limited to the upper bearing 6 and may be formed on the intermediate plate 7 or the lower bearing 8.

  Next, the operation of the refrigerant will be described first. As shown in FIG. 5A, the internal space of the first cylinder 9 is configured such that the expansion chamber 19 is partitioned into a high-pressure side expansion chamber 19a and a low-pressure side expansion chamber 19b by the vane 12a. . The high-pressure side expansion chamber 19a gradually increases in volume due to the flow of high-pressure refrigerant, causing the rotor 12 to revolve counterclockwise, and the crankshaft 11a and the shaft 11 connected thereto are made to react with each other. By rotating clockwise, the refrigerant expands in the low-pressure side expansion chamber 19b to increase the volume, so that the low-pressure state is achieved. The refrigerant having a low pressure in the low pressure side expansion chamber 19b is pressed by the revolving rotor 12 and flows out of the refrigerant outflow hole 15.

As shown in FIG. 5A, the high-pressure refrigerant flowing out of the radiator 3 flows into the high-pressure side expansion chamber 19a from the refrigerant inflow hole 14 through the pipe connector 14a. At this time, during the revolving motion of the rotor 12, the angle range of the rotor 12 in the inflow process in which the high-pressure refrigerant is supplied into the cylinder 9 is determined in advance, and is cut off when a certain amount flows. Yes. As shown in FIG. 5B, the high-pressure refrigerant that has flowed into the high-pressure side expansion chamber 19a drives the rotor 12 to revolve counterclockwise at a high pressure. The crankshaft 11a loosely fitted on the inner peripheral surface of the rotor 12 rotates while sliding with the inner peripheral surface of the rotor 12, and the shaft 11 connected thereto is rotated counterclockwise. It has become. Further, the high-pressure side expansion chamber 19a having an increased volume moves to the low-pressure side expansion chamber 19b as the rotor 12 revolves, and the refrigerant that has expanded to a low pressure is shown in FIG. It flows in the refrigerant | coolant outflow hole 15 from the outflow hole 15a which is located in the vicinity of the vane 12a and becomes the end point side of an expansion process, and flows out outside through this. Further, as described above, one end of the shaft 11 is connected to a generator or the like, and when the shaft 11 is driven to rotate, the generator or the like performs a power generation action, thereby expanding the expansion energy of the refrigerant. The tip seal 22 housed in the lower communication groove 9a of the first cylinder 9 can be effectively recovered without being discarded, as shown in FIG. The communication hole 9 b communicated with the refrigerant outflow hole 15 by being pressed by the bottom surface of the lower communication groove 9 a is closed. This is because when the pressure P1 of the low-pressure side expansion chamber 19b is higher than the pressure P2 on the refrigerant outflow hole 15 side, the differential pressure is about 1/4 turn from the outflow hole 15a of the refrigerant outflow hole 15. By opening the tip seal 22 from the opening 6b located on the rear side via the upper communication groove 21 and pressing the tip seal 22 against the bottom surface of the lower communication groove 9a.

  When the refrigerant expansion ratio in the refrigerant circuit 1 becomes larger than the design expansion ratio of the expander 4 due to changes in the operating environment or operating conditions, the pressure P1 in the low-pressure side expansion chamber 19b becomes the pressure on the refrigerant outflow hole 15 side. A state of lower than P2 occurs, so-called an overexpansion phenomenon occurs in the expander 4, thereby causing a problem that energy recovery efficiency is lowered. When the overexpansion phenomenon occurs, as shown in FIG. 6 (B), the differential pressure between the pressure P2 on the refrigerant outflow hole 15 side and the pressure P1 on the low pressure side expansion chamber 19b passes through the communication hole 9b. The tip seal 22 is placed on the tip seal 22 so as to be separated from the bottom surface of the lower communication groove 9a.

  When the chip seal 22 is separated from the bottom surface of the lower communication groove 9a, the refrigerant on the refrigerant outflow hole 15 side passes through the communication hole 9b and the upper communication groove 21 as shown by an arrow in FIG. The low pressure side expansion chamber 19b flows backward from the opening 6b located on the starting point side to recover the pressure in the low pressure side expansion chamber 19b. Thereby, the pressure of the low pressure side expansion chamber 19b and the refrigerant | coolant outflow hole 15 side can be balanced, and an overexpansion phenomenon can be suppressed. When the pressure in the low pressure side expansion chamber 19b is restored, the tip seal 22 again closes the communication hole 9b.

  Next, a second embodiment will be described. In the second embodiment, as shown in FIG. 7A, a groove 24 is formed in an arc shape on one side of the rotor 23, and the longitudinal and lateral dimensions of the cross section of the groove 24 are smaller than the groove 24. A lengthy chip seal 25 is accommodated. Further, the rotor 23 has a first through hole 24 a having one end opened to the low pressure side expansion chamber 19 b located in the revolving motion direction from the contact point with the peripheral wall of the cylinder 9 so as to be orthogonal to the inner wall surface of the cylinder 9. Further, as shown in FIG. 7C, the rotor 23 includes a high-pressure side expansion chamber located on the rear side of the revolving motion from the contact point between the rotor 23 and the peripheral wall of the cylinder 9. One end is opened to 19a, and the 2nd communicating hole 24b formed in the L-shaped section is provided, and the other end of these 1st communicating hole 24a and the 2nd communicating hole 24b is the both ends of the above-mentioned groove 24, respectively. It communicates with the department. Further, as shown in FIG. 7D, a notch 25a is formed in a substantially triangular shape at a portion of the tip seal 25 corresponding to the position of the second communication hole 24b. When the phenomenon occurs, the refrigerant in the low pressure side expansion chamber 19b flows into the high pressure side expansion chamber 19a through the notch 25a.

  Next, the operation will be described. When the refrigerant pressure in the high-pressure side expansion chamber 19a is higher than that in the low-pressure side expansion chamber 19b, the differential pressure is shown in FIG. 7C through the first through hole 24b. 25, the tip seal 25 is pressed toward the second communication hole 24a as shown in FIG. In this state, the second communication hole 24a is blocked.

  When an overexpanding phenomenon occurs at the position where the rotor 23 revolves toward the refrigerant outflow hole 15 and the refrigerant pressure in the high pressure side expansion chamber 19a is lower than that in the low pressure side expansion chamber 19b, As shown in FIG. 7 (E), the differential pressure is applied to the tip seal 25 through the first series of through holes 24a, and the tip seal 25 is moved to the second seal as shown in FIG. 7 (F). Press toward the communication hole 24b. The refrigerant gas that has pressed the tip seal 25 toward the second communication hole 24b flows back to the high-pressure side expansion chamber 19a through the notch 25a and the second communication hole 24b formed in the tip seal 25. Thus, the pressure in the high-pressure side expansion chamber 19a is recovered, and the overexpansion phenomenon is suppressed.

  As described above, the upper communication groove 21 is formed on the upper bearing 6 side, the lower communication groove 9a is formed on the first cylinder 9 side, and the upper communication groove 21 and the lower communication groove 9a are The expansion chamber 19 and the refrigerant outflow hole 15 are connected in a curved shape, a communication hole 9b communicating with the refrigerant outflow hole 15 is formed in the lower communication groove 9a, and the lower communication groove 9a By storing a long chip seal 22 made of a resin material and having elasticity so as to close the communication hole 9b, when an overexpansion phenomenon occurs, the refrigerant outflow hole 15 side and the low pressure side expansion chamber 19b A differential pressure is applied to the tip seal 22 to separate the tip seal 22 from the bottom surface of the lower communication groove 9a. When the tip seal 22 is separated from the bottom surface of the lower communication groove 9a, the refrigerant on the refrigerant outflow hole 15 side flows back to the low-pressure side expansion chamber 19b, thereby recovering the pressure in the low-pressure side expansion chamber 19b. The expansion phenomenon can be accurately suppressed. The same applies to the second cylinder 10 side. Further, as described in the second embodiment, when the chip seal 25 is accommodated in the groove 24 formed in the rotor 23 and an overexpansion phenomenon occurs, the low pressure side expansion chamber 19b is connected to the second communication hole 26b side. By allowing the refrigerant to flow backward, the overexpansion phenomenon can be suppressed.

  The tip seal 22 made of a resin material is accommodated in the lower communication groove 9a without the need for a pressure sensor, an electromagnetic on-off valve, a control unit for controlling these, and a backflow valve, and the refrigerant outflow hole 15 side. By operating with the differential pressure of the low-pressure side expansion chamber 19b, an expander that can accurately suppress the overexpansion phenomenon with a simple and cost-saving configuration can be provided.

It is a refrigerant circuit in which the expander according to the present invention is used. 1 is a cross-sectional view of an expander according to the present invention. (A), (B) is explanatory drawing which shows the cross section of the expander. (A)-(C) are principal part sectional drawing and a schematic diagram of a communicating hole. (A)-(C) are explanatory drawings which show expansion operation | movement of the expander. (A)-(B) is explanatory drawing which shows operation | movement of a bypass path. It is sectional drawing which shows a 2nd Example. It is explanatory drawing which shows the overexpansion suppression means of the conventional expander.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerant circuit 2 Compressor 3 Radiator 4 Expander 4a Upper cover 4b Main case 4c Lower cover 5 Heat absorber 6 Upper bearing 6a Upper communication groove 6b Opening 7 Intermediate plate 8 Lower bearing 9 First cylinder 9a Lower communication groove 9b Communication hole 10 Second cylinder 11 Shaft 11a, 11b Crankshaft 12 Rotor 12a Vane 13 Rotor 14 Refrigerant inflow hole 14a Piping connector 15 Refrigerant outflow hole 15a Piping connector 16 Refrigerant inflow hole 17 Refrigerant outflow hole 18 Lubricating oil supply hole 19 Expansion chamber 19a High pressure side expansion chamber 19b Low pressure side expansion chamber 20 Bush 21 Communication portion 22 Tip seal 23 Rotor 24 Groove 24a First serial hole 24b Second communication hole 25 Tip seal 25a Notch

Claims (3)

A cylinder having an internal space, an upper bearing and a lower bearing sandwiching the upper and lower ends of the cylinder, a shaft provided with a crankshaft and supported by the upper bearing and the lower bearing, and the crank A rotor that is loosely fitted on a shaft and revolves in the internal space of the cylinder; a vane that defines the internal space; a refrigerant inflow hole that passes through the sealed container and the cylinder and allows high-pressure fluid to flow into the internal space; and A refrigerant outflow hole for allowing a low-pressure fluid to flow out from the internal space, the high-pressure fluid from the refrigerant inflow hole is expanded in the internal space to revolve the rotor, and the expanded and low-pressure fluid is converted into the refrigerant In the expander that flows out from the outflow hole,
Wherein the upper bearing or the lower bearing, while the one end opening into the inner space and the other end to form the upper communicating groove to overlap on the projection plane as seen from the shaft rotational axis to the refrigerant outlet hole, the cylinder A lower communication groove that is opposed to the upper communication groove and has a communication hole that communicates with the refrigerant outflow hole is formed in the lower communication groove due to a differential pressure between the internal space and the refrigerant outflow hole. An expander comprising a chip seal that operates to open and close the communication hole. A cylinder having an internal space, an upper bearing and a lower bearing sandwiching the upper and lower ends of the cylinder, a shaft provided with a crankshaft and supported by the upper bearing and the lower bearing, and the crank A rotor that is loosely fitted to a shaft and revolves in an internal space of the cylinder with one end in contact with a peripheral wall of the internal space, a vane that partitions the internal space, the sealed container, and the cylinder, and passes through the internal space. A refrigerant inflow hole through which high-pressure fluid flows into the space and a refrigerant outflow hole through which low-pressure fluid flows out from the internal space. The high-pressure fluid from the refrigerant inflow hole is expanded in the internal space to revolve the rotor. In the expander which is caused to flow out from the refrigerant outflow hole, the expanded and low pressure fluid,
The rotor is provided with a first through hole that is located in the revolving motion direction from the contact point between the rotor and the peripheral wall and is open at one end, and on the rear side of the revolving motion from the contact point between the rotor and the peripheral wall. A second communication hole having one end opened and a groove communicating with the other end of the first communication hole and the other end of the second communication hole on one side of the rotor; An expander comprising: a chip seal that operates in accordance with a differential pressure between the first communication hole and the second communication hole.   In the position where the rotor is driven to revolve toward the refrigerant outflow hole side, the tip seal closes the first communication hole when the pressure of the second communication hole is higher than the first communication hole, When the pressure of the second communication hole is lower than that of the first communication hole, the second communication hole and the first communication hole are communicated through a notch provided in the chip seal. The expander according to claim 2.

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