JP2008190723A - Expansion machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion machine, having high power recovery efficiency by achieving increase in expansion volume conformable to the expansion characteristic of a refrigerant. <P>SOLUTION: This expansion machine includes: a shaft 31 having three or more eccentric parts 31a, 31b, 31c; three or more pistons 41, 42, 43 fitted to the eccentric parts 31a, 31b, 31c, respectively and rotated eccentrically; three or more cylinders 21, 22, 23, the inner surfaces of which are cylindrical, which are disposed so that the inner surfaces are partially in contact with the pistons 41, 42, 43; and three or more partition members for partitioning the space formed by the respective pistons 41, 42, 43 and the respective cylinders 21, 22, 23 into a suction part for sucking a refrigerant and a discharge part for discharging the refrigerant, wherein the cylinders 21, 22, 23 are connected to each oter in the longitudinal direction of the shaft 31, and as the refrigerant goes from the upstream side of a refrigerant passage to the upstream side thereof, the space formed by the respective pistons 41, 42, 43 and the respective cylinders 21, 22, 23 is increased in size. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an expander that operates by a high-pressure compressive fluid to generate power, and particularly relates to an expander that replaces a throttle mechanism in a refrigeration cycle and collects expansion power of a refrigerant.

  Conventionally, rotary expanders have been disclosed as expanders used in refrigeration cycles (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  An example of such a conventional expander is shown in FIGS. 13 is a cross-sectional view taken along the line ZZ in FIG. 12, and FIG. 14 is an explanatory diagram for explaining the operation of the expander.

  As shown in FIGS. 12 and 13, the expander is provided in a sealed container 701, a cylinder 702, a shaft 703 having an eccentric portion 703 a, a piston 704 that performs eccentric rotational motion inside the cylinder 702, and a cylinder 702. A vane groove 702a, a vane 705 that reciprocates inside the vane groove 702a, a vane spring 706, an upper bearing member 707 and a lower bearing member 708 that support the shaft 703, a suction pipe 709 that sucks refrigerant, It is comprised from the discharge pipe 710 etc. which discharge a refrigerant | coolant. An expansion chamber 712 partitioned by a vane 705 is formed in a space surrounded by the cylinder 702, the piston 704, the upper bearing member 707, and the lower bearing member 708. The upper bearing member 707 includes a suction space 707a, a suction path 707b, and a suction hole 707c serving as an opening on the expansion chamber 712 side of the suction path 707b. The shaft 703 is provided with an axial path 703b and a radial path 703c. Further, the cylinder 702 is provided with a discharge hole 702 b for discharging the refrigerant from the expansion chamber 712 to the discharge space 720 on the side opposite to the suction hole 707 c with the vane 705 interposed therebetween.

  The operation of such a conventional expander will be described. As shown in FIG. 12, the high-pressure refrigerant flows from the suction pipe 709 through the suction space 707a and the axial path 703b of the shaft 703 into the radial path 703c of the shaft 703. As shown in FIG. 13, the radial path 703 c of the shaft 703 opens only in a certain range of the outer peripheral surface of the shaft 703, and communicates with the suction path 707 b of the upper bearing member 707 as the shaft 703 rotates. Repeatedly discontinue communication. When the radial path 703c and the suction path 707b communicate with each other, the refrigerant is sucked into the expansion chamber 712 from the radial path 703c through the suction path 707b and the suction hole 707c.

  Hereinafter, the operation of the expander will be described using FIGS. 14A to 14D and focusing on the expansion chamber 712. FIG. FIG. 14A shows a state immediately before the start of the suction stroke. When the shaft 703 rotates counterclockwise from this state, the radial path 703c of the shaft 703 and the suction path 707b of the upper bearing member 707 communicate with each other, and a suction stroke for allowing high-pressure refrigerant to flow into the expansion chamber 712 is started. . Further, in the state of FIG. 14B after the shaft 703 rotates counterclockwise, the communication between the radial path 703c of the shaft 703 and the suction path 707b of the upper bearing member 707 is cut off, and the suction stroke is completed. The volume of the expansion chamber 712 at this time becomes the suction volume Vs of the expander. Thereafter, the high-pressure refrigerant sucked into the expansion chamber 712 enters an expansion stroke in which the shaft 703 is rotated in the direction in which the volume of the expansion chamber 712 increases, and the expansion stroke is reduced, and the state shown in FIG. ) State. This state is a state immediately before the expansion chamber 712 communicates with the discharge hole 702b, and the volume of the expansion chamber 712 at this time becomes the discharge volume Vd of the expander. Thereafter, when the shaft 703 rotates slightly, the expansion chamber 712 communicates with the discharge hole 702b and a discharge stroke is started. As the volume of the expansion chamber 712 decreases, the refrigerant is discharged from the discharge hole 702b to the discharge space 720. The low-pressure refrigerant stored in the discharge space 720 is discharged from the discharge pipe 710 to the outside of the expander.

  That is, in the above expander, the transition from the suction stroke to the expansion stroke depends on the opening and closing of the inflow timing control means by the communication between the radial path 703 c provided in the shaft 703 and the expansion chamber 712.

  An example in which such an expander is used in a refrigeration cycle is disclosed, and an example in which carbon dioxide that is more effective in preventing global warming than a chlorofluorocarbon refrigerant is used as a refrigerant is disclosed (for example, see Patent Document 4). .

  FIG. 15 is a conceptual diagram of a refrigeration cycle using carbon dioxide as a refrigerant. FIG. 15 (a) is a normal refrigeration cycle, FIG. 15 (b) is a refrigeration cycle using an expander, and FIG. It is a Mollier diagram which shows the relationship between the pressure of a refrigerating cycle, and enthalpy.

  15A includes a compressor 801, a gas cooler 802, an expansion valve 803, and an evaporator 804, and the compressor 801 is driven by a driving element 805 such as a motor. The Mollier diagram in this case corresponds to A-B-C-D in FIG.

  On the other hand, in the refrigeration cycle using the expander shown in FIG. 15B, the expander 806 is used instead of the expansion valve 803 in FIG. 15A, and the shaft of the expander 806 is connected to the compressor via the drive element 805. It is directly connected to the shaft 801. The Mollier diagram in this case is A-B-C-D 'in FIG. 15C, considering that the expansion stroke of the refrigerant in the expander 806 is approximately adiabatic expansion. By adopting such a refrigeration cycle configuration, it is possible to reduce the load on the driving element 805 by assisting the driving of the compressor 801 using the rotational power recovered in the expansion stroke of the refrigerant of the expander 806. it can.

Furthermore, the enthalpy difference of the refrigerant flowing into the evaporator 804 increases at a portion corresponding to DD ′ on the Mollier diagram, and the refrigeration capacity can be improved. In FIG. 15C, a point R is a critical point of carbon dioxide as a refrigerant, and the gas cooler 802 as a radiator operates in a supercritical state where the pressure is higher than that. The refrigerant flows into the expander 806 with the outlet of the gas cooler 802 at point C, and the state changes like CQ'-D ', and the enthalpy difference DD' of the refrigerant is recovered by the expander 806. ing.
JP-A-8-82296 JP-A-8-338356 JP 2003-172244 A JP 2001-153077 A

  In such a conventional expander, when the suction of refrigerant is completed, that is, the suction volume at the start of expansion is Vs, and when the discharge is started, that is, the discharge volume at the end of expansion is Vd, Vs and Vd are respectively controlled in inflow timing. The specific expansion ratio Vd / Vs is determined by the means and the discharge hole. FIG. 16 shows the relationship between pressure and volume with respect to time in the expansion stroke CD ′ of FIG. Here, the pressure in the expansion chamber at the start of the expansion stroke of the refrigerant is Ps, and the pressure in the expansion chamber at the end of the expansion stroke is Pd.

  As shown in FIG. 16A, the conventional expander has a constant expansion ratio (Vd / Vs), and the volume increase rate is sinusoidal. The change in expansion pressure when the refrigerant expands from the supercritical state ideally changes in a single-phase state from the supercritical state to the vicinity of the saturated liquid, as shown by the solid line in FIG. It expands into a gas-liquid two-phase state. However, in reality, a pressure drop due to a phase change delay as shown by the broken line portion occurs in the vicinity of the inflection point pressure Pm.

  That is, as shown in FIG. 15C, since the expansion from the point C in the supercritical state to the saturated liquid point Q ′ is a single-phase expansion, the expansion rate is 10% or less. On the other hand, since the expansion from the saturated liquid point Q ′ to the point D ′ in the gas-liquid two-phase state is a multiphase expansion that expands from a liquid to a gas-liquid two-phase state containing gas and liquid, the expansion rate is about 200%. It also becomes. Therefore, if an attempt is made to expand at the same expansion rate over the entire region of the expansion stroke as in the prior art, as shown in FIG. 16 (b), the pressure drop from the point C to the saturated liquid point Q ' Occurs in a very short time of about 1/20 of the time required for the pressure drop from to D ′. For this reason, in the phase change from liquid to gas starting from the point Q ′, the phase change speed does not catch up with the pressure drop speed, causing a so-called phase change delay, and the pressure drop as shown by the broken line in FIG. Come on. Since the recovery power of the expander is determined by the area of the diagram (PV line) showing the relationship between the pressure and volume of the refrigerant in the expansion stroke, when such a phase change delay occurs, the pressure drop The problem was that the power that could be recovered by the amount decreased.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described conventional problems, and to suppress the occurrence of a phase change delay in the expansion stroke with a simple configuration, and to realize an expander excellent in power recovery efficiency.

  In order to solve the above-described problems, the expander of the present invention has a shaft having three or more eccentric portions, three or more pistons that are fitted to the eccentric portions and rotated eccentrically, and an inner surface is cylindrical. And three or more cylinders arranged so that a part of the inner surface is in contact with the piston, and each space formed by the piston and the cylinder is divided into a suction portion for sucking refrigerant and a discharge portion for discharging refrigerant. And a plurality of partition members, and cylinders are connected in the longitudinal direction of the shaft so that the space on the downstream side of the refrigerant path is larger than the space on the upstream side of the refrigerant path.

  According to such a configuration, the expansion chamber volume increases in accordance with the expansion characteristics of the refrigerant, and an expander with high power recovery efficiency can be realized.

  Further, the cylinder has the same inner diameter and the piston has the same outer diameter, and the cylinder height of the cylinder may be increased from the upstream side to the downstream side of the refrigerant path. The expansion chamber volume can be made variable.

  Furthermore, the cylinder has the same cylindrical height and the piston has the same outer diameter, and the cylinder inner diameter may be increased from the upstream side to the downstream side of the refrigerant path, thereby realizing a small expander. Thus, the expansion chamber volume of the expander can be easily made variable.

  Further, the cylinder has the same inner diameter and the same cylinder height, and the outer diameter of the piston may be reduced from the upstream side to the downstream side of the refrigerant path, and the expansion chamber volume of the expander can be easily made variable. be able to.

  Further, in the expansion chamber formed by the discharge portion of the first cylinder on the most upstream side of the refrigerant path and the suction portion of the second cylinder connected to the first cylinder, the refrigerant is changed from the supercritical state or the liquid state to the saturated liquid line. You may make it expand | swell to the gas-liquid two-phase area | region of the vicinity.

  According to such a configuration, in response to switching between cooling operation and heating operation of the refrigeration cycle, the expansion in the single phase region and the expansion accompanied by the phase change to the gas are separated, and due to the phase change delay An expander that does not cause a pressure drop can be realized.

  According to the expander of the present invention, an increase in the volume of the expansion chamber that matches the expansion characteristics of the refrigerant can be realized, and an expander with high power recovery efficiency can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of an expander according to Embodiment 1 of the present invention. 2 is a cross-sectional view of FIG. 1, FIG. 2 (a) is a cross-sectional view taken along line AA of FIG. 1, FIG. 2 (b) is a cross-sectional view taken along line BB of FIG. Shows a cross-sectional view taken along the line CC of FIG.

  In the expander according to Embodiment 1 of the present invention, an expansion mechanism unit 500 and a power recovery mechanism unit 600 are disposed in the sealed container 1, and the expansion mechanism unit 500 and the power recovery mechanism unit 600 are connected by a shaft 31. It is connected. The shaft 31 is pivotally supported by a lower bearing 82 and an upper bearing 81 fixed to the hermetic container 1, and sucks up the lubricating oil 104 stored in the lower part of the hermetic container 1 by the rotation of the shaft 31, so that the upper bearing 81 The lower bearing 82 and the sliding portion such as the expansion mechanism 500 are lubricated by lubrication. The sealed container 1 is provided with a suction pipe 9 for sucking in the refrigerant to be expanded and a discharge pipe 10 for discharging the expanded refrigerant. The refrigerant sucked into the expansion mechanism unit 500 from the suction pipe 9 is expanded by the expansion mechanism unit 500, then discharged from the discharge pipe 10 to the outside of the sealed container 1, and supplied to the evaporator of the refrigeration cycle. Carbon dioxide is used as the refrigerant.

  When the refrigerant expands in the expansion mechanism unit 500, a rotational force is generated in the shaft 31. The power recovery mechanism unit 600 connected to the shaft 31 constitutes a power generation motor 102 composed of the rotor 100 and the stator 101 to recover the rotational force of the shaft 31 as electric power, and through the sealed terminal 103 provided in the sealed container 1. Supply power to the outside.

  The expansion mechanism 500 includes a plurality of cylinders and a plurality of pistons that rotate eccentrically inside the cylinder. Hereinafter, the details of the configuration of the expansion mechanism unit 500 in the present embodiment will be described with reference to FIGS.

  In the expansion mechanism 500, the third cylinder 23, the second intermediate member 72, the second cylinder 22, the first intermediate member 71, the first cylinder 21, and the upper bearing 81 are sequentially stacked on the lower bearing 82 and fastened. Yes. Further, the shaft 31 includes a first eccentric portion 31 a corresponding to the position of the first cylinder 21, a second eccentric portion 31 b corresponding to the position of the second cylinder 22, and a third eccentric portion corresponding to the position of the third cylinder 23. 31c is provided. A first piston 41 is fitted to the first eccentric portion 31a, a second piston 42 is fitted to the second eccentric portion 31b, and a third piston 43 is fitted to the third eccentric portion 31c. The first eccentric portion 31 a, the second eccentric portion 31 b, and the third eccentric portion 31 c are provided at the same position in the circumferential direction of the shaft 31 and are eccentric from the axis of the shaft 31 by the same amount.

  In the present embodiment, the inner diameters of the cylinders of the first cylinder 21, the second cylinder 22, and the third cylinder 23 are the same, and the cylinder volumes are made different by making the cylinder heights different. Further, the outer diameters of the pistons fitted to the eccentric portions are the same for the first piston 41, the second piston 42, and the third piston 43. Therefore, the space volume formed by each cylinder volume and the piston is made different depending on the cylinder height of each cylinder. Therefore, the high-pressure refrigerant sucked into the expander from the suction pipe 9 is sucked into the first cylinder 21 of the expansion mechanism unit 500, and then converted into the low-pressure refrigerant via the second cylinder 22 and the third cylinder 23. It expands and is discharged from the discharge pipe 10.

  Next, details of the configuration in each cylinder will be described. The upper bearing 81 located at the upper part of the first cylinder 21 is provided with a first suction hole 21a communicating with the suction pipe 9 and opens into the cylinder of the first cylinder 21 as shown in FIG. . As shown in FIGS. 1 and 3, the first intermediate member 71 located in the lower part of the first cylinder 21 is provided with a first discharge hole 21 b that opens into the cylinder of the first cylinder 21. Therefore, the first cylinder 21 is configured such that the upper and lower ends are sandwiched between the upper bearing 81 and the first intermediate member 71.

  As shown in FIG. 2 (a), the cylindrical inner surface of the first cylinder 21 is arranged so that a part of the outer peripheral surface of the first piston 41 fitted to the first eccentric portion 31a of the shaft 31 is in contact with it. The first piston 41 rotates eccentrically while contacting the inner surface of the cylinder by the rotation of the shaft 31. Further, a space formed by the cylinder of the first cylinder 21 and the first piston 41 is formed between the first suction hole 21a and the first discharge hole 21b, and the first suction part 121a and the first discharge part 121b. The 1st vane 51 partitioned off into is arrange | positioned as a partition member. The vane groove provided in the first cylinder 21 is configured such that the first vane 51 reciprocates according to the eccentric rotation of the first piston 41 while the tip end portion is in contact with the outer peripheral surface of the first piston 41 that rotates eccentrically. It is inserted into 21 d and pressed by the vane spring 61.

  The configurations of the second cylinder 22 and the third cylinder 23 are the same as those of the first cylinder 21. As shown in FIG. 1, the second cylinder 22 is configured to be sandwiched between a first intermediate member 71 located at the upper part and a second intermediate member 72 located at the lower part. As shown in FIG. 2B, the first intermediate member 71 is provided with a second suction hole 22a that opens into the cylinder of the second cylinder 22, and the second intermediate member 72 is provided with a second discharge hole 22b. An opening is provided in the cylinder of the cylinder 22. Therefore, a passage is formed in the first intermediate member 71 so that the second suction hole 22 a communicates with the first discharge hole 21 b that opens in the cylinder of the first cylinder 21. A part of the outer peripheral surface of the second piston 42 fitted to the second eccentric portion 31 b of the shaft 31 is in contact with the cylindrical inner surface of the second cylinder 22, and the second piston 42 is rotated by the rotation of the shaft 31. It is designed to rotate eccentrically while contacting the inner surface of the cylinder. Further, a space formed by the cylinder of the second cylinder 22 and the second piston 42 is formed between the second suction hole 22a and the second discharge hole 22b, and the second suction part 122a and the second discharge part 122b. A second vane 52 that divides into two is arranged as a partition member. The second vane 52 has a vane groove provided in the second cylinder 22 so as to reciprocate according to the eccentric rotation of the second piston 42 while the tip end portion is in contact with the outer peripheral surface of the second piston 42 that rotates eccentrically. It is inserted into 22 d and pressed by the vane spring 62.

  Next, the configuration of the third cylinder 23 will be described. As shown in FIG. 1, the third cylinder 23 is sandwiched between a second intermediate member 72 located at the upper part and a lower bearing 82 located at the lower part. A third suction hole 23 a is provided in the second intermediate member 72 so as to open in the cylinder of the third cylinder 23, and a third discharge hole 23 b is provided in the lower bearing 82 so as to open in the cylinder of the third cylinder 23. Yes. Therefore, a passage is formed in the second intermediate member 72 so that the third suction hole 23 a communicates with the second discharge hole 22 b opened in the cylinder of the second cylinder 22. Further, the third discharge hole 23 b communicates with the space in the sealed container 1 and is discharged from the discharge pipe 10 to the outside.

  As shown in FIG. 2 (c), the cylindrical inner surface of the third cylinder 23 is provided with a part of the outer peripheral surface of the third piston 43 fitted to the third eccentric portion 31c of the shaft 31, The rotation of the shaft 31 causes the third piston 43 to rotate eccentrically while contacting the cylindrical inner surface. Further, a space formed by the cylinder of the third cylinder 23 and the third piston 43 is formed between the third suction hole 23a and the third discharge hole 23b, and the third suction part 123a and the third discharge part 123b. A third vane 53 is divided as a partition member. The third vane 53 has a vane groove provided in the third cylinder 23 so as to reciprocate according to the eccentric rotation of the third piston 43 while the tip end portion is in contact with the outer peripheral surface of the third piston 43 rotating eccentrically. 23d and pressed by the vane spring 63.

  3A and 3B are diagrams showing the configuration of the first intermediate member 71, in which FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along the line D-D in FIG. FIG. 4 is a view showing the configuration of the second intermediate member 72, FIG. 4 (a) is a plan view, and FIG. 4 (b) is a cross-sectional view taken along the line EE of FIG. 4 (a).

  As shown in FIG. 3, the first communication passage 90 that connects the first discharge hole 21 b on the first cylinder 21 side and the second suction hole 22 a on the second cylinder 22 side provided in the first intermediate member 71 includes: The first intermediate member 71 is formed in an oblique direction. As shown in FIG. 4, the second communication passage 91 connecting the second discharge hole 22 b on the second cylinder 22 side and the third suction hole 23 a on the third cylinder 23 provided in the second intermediate member 72. Is formed in the second intermediate member 72 in an oblique direction.

  The operation of the expander of the present embodiment configured as described above will be described with reference to FIGS. FIG. 5 shows an operation state in the first cylinder 21 and the second cylinder 22 with respect to the rotation angle of the shaft 31, and FIG. 6 shows an operation state in the third cylinder 23 in the same manner. FIG. 7 shows the expansion characteristics of the expander according to Embodiment 1 of the present invention. FIG. 7A shows the relationship between the rotation angle of the shaft 31 and the expansion volume, and FIG. 7B shows the relationship between the rotation angle of the shaft 31 and the expansion pressure.

  The refrigerant sucked into the expander passes through the refrigerant path in the order of the first cylinder 21, the second cylinder 22, and the third cylinder 23. In the present embodiment, the first discharge portion 121b of the first cylinder 21 and the second suction portion 122a of the second cylinder 22 connected by the first communication passage 90 of the first intermediate member 71 shown in FIG. An expansion chamber is formed, and the second discharge part 122b of the second cylinder 22 and the third suction part 123a of the third cylinder 23 connected by the second communication passage 91 of the second intermediate member 72 shown in FIG. A second expansion chamber is formed.

  The supercritical high-pressure refrigerant of carbon dioxide flowing in from the suction pipe 9 attached to the sealed container 1 passes through the inflow passage (not shown) provided in the upper bearing 81 through the first suction hole 21a to the first cylinder 21. Flow into. The shaft 31 rotates counterclockwise from the position of the rotation angle 0 ° shown in FIG. 5A and the suction stroke to the first suction portion 121a is started, and the rotation angle 270 ° shown in FIG. After one revolution, the inhalation stroke is completed. At this time, as shown in FIG. 7, the first discharge part 121b filled with the supercritical refrigerant has the volume Vs1 and the suction pressure Ps.

  Thereafter, the refrigerant in the first discharge part 121b communicates with the first discharge hole 21b when the shaft 31 passes a rotation angle of 360 °, and from the first communication passage 90 provided in the first intermediate member 71 to the second cylinder 22 side. The second suction hole 22a communicates with the second suction part 122a. The refrigerant sucked into the second suction part 122a is communicated with the second discharge hole 22b after the shaft 31 is further rotated by 360 °, and from the second communication passage 91 provided in the second intermediate member 72 to the third cylinder 23. It communicates with the third suction part 123a through the third suction hole 23a on the side. Then, when the shaft 31 further rotates 360 °, the shaft 31 is discharged from the third discharge portion 123b via the third discharge hole 23b.

  In the first embodiment of the present invention, the height of the first cylinder 21 is 8 mm, the height of the second cylinder 22 is 8.8 mm, and the height of the third cylinder 23 is 20 mm. Assuming that the volume at the time when suction is completed in the first cylinder 21 is Vs1, the volume at the time when suction is completed in the second cylinder 22 is Vs2, and the volume at the time when suction is completed in the third cylinder 23 is Vs3, Vs1: Vs2: Vs3 = 1: 1.1: 2.5. Therefore, since the volume of the first expansion chamber is the sum of the first discharge portion 121b and the second suction portion 122a as described above, the expansion ratio (Vs2 / Vs1) of the first expansion chamber that expands from Vs1 to Vs2 is 1.1. On the other hand, since the volume of the second expansion chamber is the sum of the second discharge portion 122b and the third suction portion 123a, the expansion ratio (Vs3 / Vs2) of the second expansion chamber expanding from Vs2 to Vs3 is about 2.3. It becomes. Normally, when an expander is used in a refrigeration cycle using carbon dioxide as a refrigerant, it expands from a supercritical state to a gas-liquid two-phase region through a saturated liquid, but the expansion ratio from the supercritical state to the saturated liquid is Even if the use of the refrigeration cycle such as air conditioner and various temperature conditions in them are taken into consideration, it is less than 1.1. Therefore, by making such a cylinder height, it is possible to expand from the supercritical fluid to the gas-liquid two-phase region slightly exceeding the saturated liquid in the first expansion chamber.

  As shown in FIG. 7A, the first expansion chamber formed by the first discharge part 121b and the second suction part 122a enters an expansion stroke in which the shaft 31 is rotated and expanded and depressurized while increasing the volume. And the volume of the 1st discharge part 121b becomes zero in the state where the rotation angle of the shaft 31 is 720 degrees, and it expand | swells to the volume Vs2 of the 2nd discharge part 122b. At this time, the pressure in the first expansion chamber (second suction part 122a) is Pm. In this process, the first stage expansion step is performed. That is, in the first expansion chamber, a gentle expansion with an expansion ratio of only 1.1 can be realized.

  Therefore, when carbon dioxide is used as a refrigerant, expansion with a small expansion ratio can be realized from a high-pressure supercritical state to a saturated liquid or a gas-liquid two-phase region exceeding the saturated liquid line. Therefore, it is possible to suppress the pressure drop that occurs when the phase change speed in the gas-liquid two-phase region does not catch up with the pressure drop speed.

  The refrigerant of the second discharge part 122b communicates with the second discharge hole 22b when the rotation angle of the shaft 31 exceeds 720 °, and the third cylinder 23 via the second communication path 91 provided in the second intermediate member 72. The third suction hole 23 a communicates with the third suction portion 123 a of the third cylinder 23. Then, as shown in FIG. 7A, the second expansion chamber formed by the second discharge part 122b and the third suction part 123a enters an expansion stroke in which the shaft 31 is rotated and expanded and depressurized while increasing the volume. . Furthermore, in the state of 1080 ° in which the shaft 31 rotates once, the volume of the second discharge part 122b becomes zero and expands to the volume Vs3 of the third discharge part 123b. At this time, the pressure of the third suction portion 123a serving as the second expansion chamber is reduced to Pd. In this process, a second stage expansion process is performed, and a large volume expansion with an expansion ratio of about 2.3 from the vicinity of the saturated liquid to the gas-liquid two-phase state is performed, so that efficient expansion suitable for the refrigerant characteristics is achieved. Done.

  Thereafter, the refrigerant passes through the third discharge hole 23 b, is discharged into the sealed container 1 through a discharge path (not shown) provided in the lower bearing 82, and is further discharged out of the discharge pipe 10. That is, according to the expander having the three-stage configuration of the first cylinder 21, the second cylinder 22, and the third cylinder 23 as in the first embodiment of the present invention, the refrigerant sucked into the expander is 1 of the shaft 31. It is sucked into the first cylinder 21 at the rotation and expanded in the first expansion chamber at the second rotation. The third expansion chamber expands in the second expansion chamber, and the expansion stroke and the discharge stroke of the refrigerant sucked into the expander are completed by rotating the shaft 31 three times.

  As is apparent from the above operation, the present invention does not require a suction timing mechanism or the like to the expansion chamber, and can continuously suck the refrigerant into the expander and discharge the refrigerant from the expander. An expander capable of a continuously stable expansion operation can be realized. In particular, by making the expansion stroke multistage, it is possible to obtain an expansion volume that is optimal for the phase change of the refrigerant that occurs during the expansion process. Therefore, the rapid phase change of the refrigerant in the expansion process can be suppressed, the expansion energy can be efficiently recovered, and an expander with high power recovery efficiency can be realized.

  Furthermore, the expansion rate in the first expansion chamber is reduced, and the expansion is from a high-pressure supercritical state to a saturated liquid or a gas-liquid two-phase region slightly exceeding the saturated liquid line. Therefore, at least in a region including a region where the pressure drop with respect to the expansion rate from point C to point Q ′ in FIG. Therefore, the phase change speed can sufficiently catch up with the pressure drop speed, and the reduction of the recovered power due to the pressure drop due to the phase change delay can be surely prevented, thereby realizing a highly efficient expander.

  As shown in FIG. 1, in Embodiment 1 of the present invention, the first cylinder 21, the second cylinder 22, and the third cylinder 23 are sequentially arranged from the top so that the refrigerant path goes from the top to the bottom of the expander. It is arranged. According to such a configuration, the liquid refrigerant having a high density drops in the first communication passage 90 provided in the first intermediate member 71 and the second communication passage 91 provided in the second intermediate member 72 by gravity. When the liquid refrigerant having a high density stays in each communication path serving as a dead space in the expander, the expansion efficiency of the expander is reduced. However, according to the first embodiment of the present invention, such a phenomenon is prevented and the expansion efficiency is reduced. A high expander can be realized more reliably.

(Embodiment 2)
FIG. 8 is a longitudinal sectional view of the expander according to Embodiment 2 of the present invention. 9 is a cross-sectional view of FIG. 8, FIG. 9 (a) is a cross-sectional view taken along the line AA of FIG. 8, FIG. 9 (b) is a cross-sectional view taken along the line BB of FIG. The CC sectional view taken on the line of FIG.

  The expander according to the second embodiment of the present invention has the same basic configuration as the expander described in the first embodiment, and the same reference numerals are given to the same components. This embodiment is different from the first embodiment in the following points.

  In the first embodiment, the volume formed in each cylinder is varied by changing the height of each cylinder. However, in the present embodiment, the volume formed in each cylinder is varied as follows. Yes.

  As shown in FIGS. 8 and 9, the expander in the present embodiment includes a first vane 51, a second vane 52, and a third vane provided in the first cylinder 21, the second cylinder 22, and the third cylinder 23, respectively. The position of the vane 53 or the position of the first eccentric portion 31a, the second eccentric portion 31b, and the third eccentric portion 31c provided in the shaft 31 in the circumferential direction of the shaft 31 is the same as that in the first embodiment. Furthermore, the heights of the first cylinder 21, the second cylinder 22, and the third cylinder 23 are the same. However, the inner diameters of the first cylinder 21, the second cylinder 22, and the third cylinder 23, the amount of eccentricity of the first eccentric portion 31a, the second eccentric portion 31b, and the third eccentric portion 31c with respect to the axis of the shaft 31, and the first The outer diameters of the first piston 41, the second piston 42, and the third piston 43 are made different, and the volumes formed by the cylinders and the pistons are made different.

  That is, as in the first embodiment, the volume at the time when suction is completed in the first cylinder 21 is Vs1, the volume at the time when suction is completed in the second cylinder 22 is Vs2, and the volume is sucked in the third cylinder 23. The above dimensions are determined so that the volume at the time of completion is Vs3, and Vs1: Vs2: Vs3 = 1: 1.1: 2.5.

  Specifically, in the present embodiment, the heights of the first cylinder 21, the second cylinder 22, and the third cylinder 23 are constant, and the inner diameter D1 of the first cylinder 21, the inner diameter D2 of the second cylinder 22, and the first The eccentric amount E1 of the first eccentric portion 31a and the eccentric amount E2 of the second eccentric portion 31b are made the same, and the outer diameter Dp2 of the second piston 42 is made smaller than the outer diameter Dp1 of the first piston 41. On the other hand, in the third cylinder 23, the inner diameter D3, the eccentric amount E3 of the third eccentric portion 31c, and the outer diameter Dp3 of the third piston 43 are made larger than the dimensions of the respective components of the second cylinder 22. Yes. These dimensions are determined so as to have a ratio of Vs1: Vs2: Vs3 = 1: 1.1: 2.5.

  FIG. 10 is a cross-sectional view of each cylinder of the expander in another example of the second embodiment of the present invention, which is a more specific example of the second embodiment. In the present embodiment, the heights of the first cylinder 21, the second cylinder 22, and the third cylinder 23 are made the same, and the outer diameters of the first piston 41, the second piston 42, and the third piston 43 are made the same, By changing the inner diameter of each cylinder, the aforementioned volume is set to a ratio of Vs1: Vs2: Vs3 = 1: 1.1: 2.5. Specifically, each component is the same as in FIG. 8 and FIG. 9, the cylinder height is the same, the outer diameter of each piston is Dp1 = Dp2 = Dp3, and the inner diameter of each cylinder is D1 <D2 <D3. Yes. Further, as shown in FIG. 10, since the same shaft 31 is used and the outer diameter of each piston is the same and the inner diameter of each cylinder is changed, the eccentric amount of each eccentric portion is E1 <E2 <E3.

  FIG. 11 is a cross-sectional view of each cylinder of the expander in another example of Embodiment 2 of the present invention. In the present embodiment, the first cylinder 21, the second cylinder 22, and the third cylinder 23 have the same height and the same inner diameter, and the first piston 41, the second piston 42, and the third piston 43 are outside the same. By changing the diameter, the above-described volume is set to a ratio of Vs1: Vs2: Vs3 = 1: 1.1: 2.5. Specifically, each component is the same as in FIGS. 8 and 9, the cylinder height is the same, the inner diameter of each cylinder is D1 = D2 = D3, and the outer diameter of each piston is Dp1> Dp2> Dp3. Yes. Further, the eccentric amounts E1, E2, and E3 of the respective eccentric portions are adjusted so as to ensure an optimum clearance between the piston and the cylinder that are appropriately adjusted.

  Since the operation of the expander in the present embodiment configured as described above is the same as that of the first embodiment, description thereof is omitted. In addition, since the operation in the expansion process of the expander in the present embodiment is the same as that in the first embodiment, it is natural that the same effect is exhibited. However, according to the present embodiment, each cylinder Or since each piston etc. can be processed from the raw material of the same thickness, processing productivity improves, Furthermore, the whole height of an expander can be made small and a compact compact expander can be implement | achieved.

  In the first embodiment and the second embodiment described above, the case where there are three cylinders has been described. However, the number of cylinders is not limited to three. That is, by further increasing the number of cylinders and, for example, further increasing the number of stages of the second expansion chamber shown in FIG. 7, it is possible to achieve an optimal expansion process depending on the refrigerant state when the refrigerant expands, It is also possible to finely control the expansion process up to the liquid line or the expansion process near the saturated liquid line.

  In the first embodiment and the second embodiment described above, the refrigerant is described as carbon dioxide. However, the present invention is applied to the case where the refrigerant is flon or the like and is expanded from a liquid single phase to a gas-liquid two phase through a saturated liquid. Needless to say, the same effect can be obtained.

  The expander of the present invention is useful as a power recovery means by recovering the expansion energy of the refrigerant in the refrigeration cycle, and is also useful as a means for recovering power from a compressible fluid other than the refrigeration cycle.

The longitudinal cross-sectional view of the expander in Embodiment 1 of this invention Cross-sectional view of each cylinder of the expander according to Embodiment 1 of the present invention The figure which shows the 1st intermediate member of the expander in Embodiment 1 of this invention The figure which shows the 2nd intermediate member of the expander in Embodiment 1 of this invention Sectional drawing of the 1st cylinder and the 2nd cylinder which show operation | movement of the expander in Embodiment 1 of this invention Sectional drawing of the 3rd cylinder which shows operation | movement of the expander in Embodiment 1 of this invention. (A) The figure which shows the relationship between the rotation angle of the shaft in Embodiment 1 of this invention, and an expansion volume (b) The figure which shows the relationship between the rotation angle of the shaft in Embodiment 1 of this invention, and expansion pressure The longitudinal cross-sectional view of the expander in Embodiment 2 of this invention Cross-sectional view of each cylinder of the expander in Embodiment 2 of the present invention Cross-sectional view of each cylinder of the expander in another example of Embodiment 2 of the present invention Cross-sectional view of each cylinder of the expander in another example of Embodiment 2 of the present invention Vertical section of a conventional expander ZZ line sectional view of FIG. Sectional view of a cylinder showing the operation of a conventional expander (A) Conceptual diagram of a conventional refrigeration cycle (b) Conceptual diagram of a refrigeration cycle using a conventional expander (c) Mollier diagram showing the relationship between pressure and enthalpy Characteristic diagram showing volume and pressure change with time of conventional expander

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 9 Suction pipe 10 Discharge pipe 21 1st cylinder 21a 1st suction hole 21b 1st discharge hole 21d, 22d, 23d Vane groove 22 2nd cylinder 22a 2nd suction hole 22b 2nd discharge hole 23 3rd cylinder 23a 1st 3 suction hole 23b 3rd discharge hole 31 shaft 31a 1st eccentric part 31b 2nd eccentric part 31c 3rd eccentric part 41 1st piston 42 2nd piston 43 3rd piston 51 1st vane 52 2nd vane 53 3rd vane 61 , 62, 63 Vane spring 71 First intermediate member 72 Second intermediate member 81 Upper bearing 82 Lower bearing 90 First communication path 91 Second communication path 100 Rotor 101 Stator 102 Generator motor 103 Sealed terminal 104 Lubricating oil 121a First suction portion 121b 1st discharge part 122a 2nd suction part 122b 2nd discharge part 123a 3rd suction | inhalation Part 123b third discharge part 500 expansion mechanism part 600 power recovery mechanism part

Claims (5)

A shaft having three or more eccentric parts;
Three or more pistons that rotate eccentrically with each of the eccentric parts;
Three or more cylinders, the inner surface of which is cylindrical and disposed so that a part of the inner surface is in contact with the piston;
Comprising three or more partition members that partition each space formed by the piston and the cylinder into a suction portion that sucks refrigerant and a discharge portion that discharges the refrigerant;
Connecting the cylinder in the longitudinal direction of the shaft;
An expander characterized in that the space on the downstream side of the refrigerant path is larger than the space on the upstream side of the refrigerant path. The cylinder has the same inner diameter and the piston has the same outer diameter, and the cylinder height of the cylinder increases as it goes from the upstream side to the downstream side of the refrigerant path.
The expander according to claim 1. The cylinders have the same cylindrical height and the pistons have the same outer diameter, and the inner diameter of the cylinder is increased from the upstream side to the downstream side of the refrigerant path.
The expander according to claim 1. The cylinder has the same inner diameter and the same cylinder height, and the outer diameter of the piston is reduced from the upstream side to the downstream side of the refrigerant path,
The expander according to claim 1. In the expansion chamber formed by the discharge part of the first cylinder on the most upstream side of the refrigerant path and the suction part of the second cylinder connected to the first cylinder, the refrigerant is changed from the supercritical state or liquid state to the vicinity of the saturated liquid line. It is characterized by expanding to the gas-liquid two-phase region,
The expander according to any one of claims 1 to 4.

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