CN111868384B

CN111868384B - Multistage compressor

Info

Publication number: CN111868384B
Application number: CN201980016332.XA
Authority: CN
Inventors: 安嶋贤哲; 岩崎正道; 寺脇宏幸
Original assignee: Fuji Electric Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2018-09-18
Filing date: 2019-09-11
Publication date: 2022-06-03
Anticipated expiration: 2039-09-11
Also published as: EP3842640A4; CN111868384A; EP3842640B1; WO2020059608A1; JP6943345B2; JPWO2020059608A1; EP3842640A1

Abstract

The invention aims to provide a multistage compressor which can integrate a plurality of valves, openings and pipes unique to two-stage compression and realize maintainability and compactness. The method comprises the following steps: a plurality of compression chambers provided in the housing; an intermediate-pressure refrigerant discharge port (123) that discharges an intermediate-pressure refrigerant (RM3) from a low-stage-side compression chamber of the plurality of compression chambers; an intermediate-pressure refrigerant suction port (122) that opens in the same direction as the intermediate-pressure refrigerant discharge port (123) and that sucks intermediate-pressure refrigerant (RM3) to the high-stage sides of the plurality of compression chambers; a high-pressure refrigerant discharge port (124) that opens in the same direction as the intermediate-pressure refrigerant discharge port (123) and discharges the high-pressure refrigerant discharged from the high-stage-side compression chambers of the plurality of compression chambers; and a refrigerant connection cover (117) detachably attached to the casing and forming an intermediate-pressure refrigerant chamber (116) communicating with the intermediate-pressure refrigerant suction port (122) and the intermediate-pressure refrigerant discharge port (123) and including an external intermediate-pressure refrigerant connection introduction port (126) opening to the outside, and a high-pressure refrigerant chamber (117) communicating with the high-pressure refrigerant discharge port (124) and including a high-pressure refrigerant discharge port (125) opening to the outside.

Description

Multistage compressor

Technical Field

The present invention relates to a multistage compressor having a multistage compression mechanism, which can achieve a reduction in size of the apparatus with a simple configuration even when the amount of refrigerant circulating to a low-stage compression mechanism and the amount of refrigerant circulating to a high-stage compression mechanism are different.

Background

Conventionally, there is a multi-stage compressor in which two stages of compression mechanisms are provided in one scroll compressor. For example, patent document 1 describes a scroll compressor in which a land portion is provided to divide a compression chamber of a fixed scroll into two stages, a low-stage compression mechanism on the outer peripheral side and a high-stage compression mechanism on the inner peripheral side are formed by the land portion, and air compressed by the low-stage compression mechanism is introduced into the high-stage compression mechanism.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2004-332556

Disclosure of Invention

Technical problem to be solved by the invention

The scroll compressor of the two-stage compression directly compresses the refrigerant circulation amount compressed in the low-stage compression mechanism in the high-stage compression mechanism. Here, when a scroll compressor of two-stage compression is applied to a compressor of two-stage compression and two-stage expansion cycle, the refrigerant of intermediate pressure expanded in the expansion valve of the high stage is introduced into the compression mechanism of the high stage, and therefore the refrigerant circulation amount introduced into the compression mechanism of the high stage is larger than the refrigerant circulation amount introduced into the compression mechanism of the low stage, and it is difficult to achieve two-stage compression. In order to realize the two-stage compression and two-stage expansion cycle, a pair of scroll compressors including a lower stage scroll compressor and a higher stage scroll compressor is required. Therefore, the scroll compressor of the two-stage compression and two-stage expansion cycle has a large-sized device structure and a complicated piping structure.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a multistage compressor which can integrate a large number of valves, ports, and pipes unique to two-stage compression and which can be maintained and made compact.

Technical scheme for solving technical problem

In order to solve the above technical problems, and achieve the object, a multistage compressor of the present invention includes: a plurality of compression chambers provided in the housing; an intermediate-pressure refrigerant discharge port that discharges an intermediate-pressure refrigerant from a low-stage-side compression chamber of the plurality of compression chambers; an intermediate-pressure refrigerant suction port that opens in the same direction as the intermediate-pressure refrigerant discharge port and sucks the intermediate-pressure refrigerant to the high-stage sides of the plurality of compression chambers; a high-pressure refrigerant discharge port that opens in the same direction as the intermediate-pressure refrigerant discharge port and discharges a high-pressure refrigerant discharged from a high-stage-side compression chamber of the plurality of compression chambers; and a refrigerant connection cover detachably attached to the case and forming an intermediate-pressure refrigerant chamber and a high-pressure refrigerant chamber, the intermediate-pressure refrigerant chamber communicating with the intermediate-pressure refrigerant suction port and the intermediate-pressure refrigerant discharge port and including an external intermediate-pressure refrigerant connection introduction port opened to the outside, the high-pressure refrigerant chamber communicating with the high-pressure refrigerant discharge port and including a high-pressure refrigerant lead-out port opened to the outside.

In the multistage compressor according to the present invention, the casing is formed with a casing intermediate-pressure refrigerant suction port that opens in the same direction as the intermediate-pressure refrigerant discharge port and discharges the intermediate-pressure refrigerant via a seal in the casing, and the intermediate-pressure refrigerant suction port and the external intermediate-pressure refrigerant connection introduction port are connected by a pipe.

In the multistage compressor according to the present invention, a high-pressure relief element is provided in the high-pressure refrigerant chamber of the casing, and the high-pressure relief element communicates the high-stage-side compression chamber with the high-pressure refrigerant chamber when an internal pressure of the high-stage-side compression chamber is equal to or higher than a predetermined value.

In the multistage compressor according to the present invention, in the above-described invention, an intermediate pressure relief element is provided in the intermediate-pressure refrigerant chamber of the casing, and the intermediate pressure relief element communicates the low-stage-side compression chamber with the intermediate-pressure refrigerant chamber when the internal pressure of the low-stage-side compression chamber is equal to or higher than a predetermined value.

In the multistage compressor according to the present invention, a check valve for preventing a backflow from the intermediate-pressure refrigerant discharge port to the compression chamber is provided in the intermediate-pressure refrigerant chamber of the casing.

In the multistage compressor according to the present invention, in the above-described invention, a check valve for preventing backflow from the high-pressure refrigerant discharge port to a compression chamber is provided in the high-pressure refrigerant chamber of the casing.

Further, a multistage compressor of the present invention in the above invention, the multistage compressor is a scroll compressor including an orbiting scroll and a fixed scroll which constitutes a part of the housing and to which the refrigerant connection cover is mounted.

In the multistage compressor according to the present invention, the volume of the intermediate-pressure refrigerant chamber is made larger than the volume of the high-pressure refrigerant chamber.

In the multistage compressor according to the present invention, the refrigerant connection cover is provided with a notch for positioning.

In the multistage compressor according to the present invention, the multistage compressor according to any one of the above inventions is applied to a heat cycle system in which two-stage compression and two-stage expansion are performed.

Effects of the invention

According to the present invention, many valves, openings, and piping that are unique to two-stage compression can be integrated, and maintainability and compactness can be achieved.

Drawings

Fig. 1 is a circuit diagram showing a schematic configuration of a heat cycle system to which a scroll compressor as a multistage compressor according to an embodiment of the present invention is applied.

Fig. 2 is a P-H diagram of the thermal cycle system shown in fig. 1.

Fig. 3 is a sectional view showing a structure of the scroll compressor.

Fig. 4 is a sectional view taken along line a-a of fig. 3.

Fig. 5 is a sectional view of the fixed scroll and the orbiting scroll shown in fig. 3.

Fig. 6 is a perspective view of the fixed scroll shown in fig. 4 as viewed obliquely from below.

Fig. 7 is a perspective view of the orbiting scroll shown in fig. 4 as viewed from obliquely above.

Fig. 8 is an explanatory diagram for explaining a compression operation of the symmetric scroll compressor.

Fig. 9 is an explanatory diagram for explaining a compression operation of the asymmetric scroll compressor.

Fig. 10 is an explanatory diagram showing a relationship between a position on the involute curve and the angle of extension.

Fig. 11 is a diagram comparing compression operations of the symmetric scroll compressor and the asymmetric scroll compressor.

Fig. 12 is an explanatory diagram for explaining reduction of recompression loss due to a compression operation of the asymmetric scroll compressor.

Fig. 13 is a sectional view showing a state when the orbiting scroll is tilted.

Fig. 14 is an explanatory diagram for explaining a decrease in compression efficiency of the outer compression portion in the state of fig. 13.

Fig. 15 is an explanatory diagram for explaining a decrease in volumetric efficiency of the inner compression portion in the state of fig. 13.

Fig. 16 is a sectional view showing a state in which an annular seal is provided on a distal end surface of an outer wall of a fixed scroll.

FIG. 17 is a sectional view taken along line B-B of the scroll compressor shown in FIG. 3 with an annular seal provided.

Fig. 18 is a cross-sectional view showing a state in which the annular seal is provided on the base plate of the orbiting scroll.

Fig. 19 is a view showing an example of providing a dividing gap in the annular seal.

Fig. 20 is a view showing an example of providing a dividing gap in the annular seal.

Fig. 21 is a view showing an example of a space portion provided in the annular seal.

Fig. 22 is a circuit diagram showing an example of the heat cycle system.

Fig. 23 is a P-H diagram of the thermal cycle system shown in fig. 22.

Fig. 24 is a circuit diagram showing an example of the heat cycle system.

Fig. 25 is a P-H diagram of the thermal cycle system shown in fig. 24.

Fig. 26 is a circuit diagram showing an example of the heat cycle system.

Fig. 27 is a P-H diagram of the thermal cycle system shown in fig. 26.

Fig. 28 is a circuit diagram showing an example of the heat cycle system.

Fig. 29 is a P-H diagram of the thermal cycle system shown in fig. 28.

Fig. 30 is a longitudinal sectional view showing a structure of a scroll compressor according to a fourth embodiment.

Fig. 31 is a perspective view of the scroll compressor shown in fig. 30 as viewed obliquely from the right.

Fig. 32 is a perspective view of the scroll compressor shown in fig. 30 viewed from diagonally left.

Fig. 33 is a perspective view of the refrigerant connection cover shown in fig. 30 as viewed from the back side.

Fig. 34 is a front view of a state in which the refrigerant connection cover is attached.

Fig. 35 is a front view of a state where the refrigerant connection cover is removed.

Detailed Description

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

[ first embodiment ]

(outline of application System)

Fig. 1 is a circuit diagram showing a schematic configuration of a heat cycle system 1 to which a scroll compressor 2 as a multistage compressor according to an embodiment of the present invention is applied. Fig. 2 is a P-H diagram of the heat cycle system 1 shown in fig. 1. The scroll compressor 2 is a two-stage compressor, and is an example of a multi-stage compressor. Further, the heat cycle of the heat cycle system 1 is a two-stage compression two-stage expansion cycle.

The high-stage compression chamber of the scroll compressor 2 generates a high-pressure refrigerant RH in the refrigerant circulation amount GH, and introduces the refrigerant into the condenser 3 (point P2 to point P3 in fig. 2). The high-pressure refrigerant RH is heat-radiated and condensed by the condenser 3, and is further supercooled by the supercooler 4 (point P3 to point P4 in fig. 2). Thereafter, the high-pressure refrigerant RH is decompressed and expanded in the high-stage expansion valve 5 (from point P4 to point P5 in fig. 2) to become an intermediate-pressure refrigerant RM, which is introduced into the gas-liquid separator 6. The vapor in the intermediate-pressure refrigerant RM, i.e., the gaseous intermediate-pressure refrigerant RM1, is introduced into the high-stage-side compression chamber of the scroll compressor 2 (point P2 in fig. 2). On the other hand, the liquid intermediate refrigerant RM2 of the intermediate refrigerant RM is decompressed and expanded (from point P6 to point P7 in fig. 2) in the low-stage expansion valve 7 to become a low-pressure refrigerant RL, which is introduced into the evaporator 8. The evaporator 8 evaporates the low-pressure refrigerant RL (from point P7 to point P1 in fig. 2), and introduces it into the low-stage compression chamber (point P1 in fig. 2) of the scroll compressor 2.

Thereafter, the low-stage compression chamber of the scroll compressor 2 compresses the introduced low-pressure refrigerant RL into the intermediate-pressure refrigerant RM 3. The high-stage side compression chamber of the scroll compressor 2 compresses the intermediate-pressure refrigerants RM1, RM3 into the high-pressure refrigerant RH. Therefore, the liquid refrigerant circulation amount GL separated by the gas-liquid separator 6 is introduced into the lower stage compression chamber of the scroll compressor 2. On the other hand, the refrigerant circulation amount GH obtained by adding the gaseous refrigerant circulation amount GM separated by the gas-liquid separator 6 and the refrigerant circulation amount GL introduced from the low-stage compression chamber is introduced into the high-stage compression chamber of the scroll compressor 2. That is, the amount of refrigerant circulated to the high-stage compression chamber is larger than the amount of refrigerant circulated to the low-stage compression chamber.

(scroll compressor)

Fig. 3 is a sectional view showing the structure of the scroll compressor 2. Further, fig. 4 is a sectional view taken along line a-a shown in fig. 3. Further, fig. 5 is a sectional view of the fixed scroll 11 and the orbiting scroll 12 shown in fig. 3. Fig. 6 is a perspective view of the fixed scroll 11 shown in fig. 4, viewed obliquely from below. Fig. 7 is a perspective view of orbiting scroll 12 shown in fig. 4, viewed obliquely from above.

The fixed scroll 11 and the orbiting scroll 12 form an outer compression unit 40 described later that functions as a low-pressure compression chamber and an inner compression unit 41 described later that functions as a high-pressure compression chamber, and perform two-stage compression. As shown in fig. 3, a fixed scroll 11 and an orbiting scroll 12 are provided in a casing 10 formed by

casings

10a, 10 b. Two-stage compression is performed by orbiting the orbiting scroll 12 around the fixed scroll 11 in the orbiting direction AL. The crank shaft 13 transmits a rotational force from an unillustrated orbiting drive source to the orbiting scroll 12. The thrust bearing 14 axially supports the rotation of the orbiting scroll 12 in the thrust direction. An intermediate pressure chamber 16 and a high pressure chamber 17 are formed in the housing 10. In addition, a balance weight 15 is provided on the crank shaft 13 for obtaining rotational balance with respect to the revolving motion of the orbiting scroll 12.

The low-pressure refrigerant suction pipe L1 is a pipe for introducing the low-pressure refrigerant RL into the outer compression portion 40. The intermediate-pressure refrigerant suction pipe L2 is a pipe for introducing the intermediate-pressure refrigerant RM1 into the intermediate pressure chamber 16. The high-pressure refrigerant discharge pipe L3 is a pipe for discharging the high-pressure refrigerant RH discharged from the inner compression portion 41 through the discharge valve 18 and the high-pressure chamber 17 to the outside of the casing 10.

(two-stage compression mechanism)

As shown in fig. 4 to 7, the fixed scroll 11 has a fixed scroll plate-like wrap 11b erected on a base plate 11 a. Orbiting scroll 12 has orbiting scroll-shaped wrap 12b erected on base plate 12 a. The fixed scroll 11 and the orbiting scroll 12 form an outer compression portion 40 and an inner compression portion 41 by meshing a tip of a fixed scroll wrap 11b and a tip of an orbiting scroll wrap 12b with each other. Further, inside the outer compression part 40 and the inner compression part 41, compression chambers are formed outside and inside the orbiting scroll 12, and the refrigerant in the compression chambers is compressed by moving the compression chambers toward the center side while reducing the volume of the compression chambers by orbiting the orbiting scroll 12.

As shown in fig. 4, a partition wall 20 connecting adjacent fixed scroll-shaped wraps 11b is provided to partition the compression chamber between a winding start position PA on the center side and a winding end position PB on the outer side of the fixed scroll-shaped wrap 11 b. In addition, the orbiting scroll plate wrap 12b is formed with a cut region E (see fig. 7) at a position corresponding to the partition wall 20 so as not to interfere with the partition wall 20 with the orbiting motion of the orbiting scroll 12. The outer compression part 40 and the inner compression part 41 are formed by the partition wall 20. As shown in fig. 5 to 7, by forming the cut region E, the orbiting scroll wrap 12b includes an orbiting scroll wrap 32 that orbits within the outer compression part 40 and an orbiting scroll wrap 33 that orbits within the inner compression part 41. Further, the fixed scroll plate-like wrap 11b has a fixed scroll plate-like wrap 30 forming the outer compression portion 40 by the partition wall 20 and a fixed scroll plate-like wrap 31 forming the inner compression portion 41.

A low-pressure refrigerant suction port 21 is formed at a winding completion position outside the orbiting scroll wrap 32 of the outer compression part 40, and the low-pressure refrigerant suction port 21 is connected to a low-pressure refrigerant suction pipe L1. Further, an intermediate-pressure refrigerant discharge port 23 is formed at a winding start position of the orbiting scroll wrap 32 of the outer compression portion 40, and the intermediate-pressure refrigerant discharge port 23 discharges the intermediate-pressure refrigerant RM3 compressed in the outer compression portion 40 to the intermediate pressure chamber 16. Further, an intermediate-pressure refrigerant suction port 22 that communicates with the intermediate pressure chamber 16 and sucks the intermediate-pressure refrigerants RM1 and RM3 is formed at a winding completion position outside the orbiting scroll wrap 33 of the inner compression portion 41. Further, a high-pressure refrigerant discharge port 24 is formed at the winding start position, i.e., the center, inside the orbiting scroll wrap 33 of the inner compression portion 41. The high-pressure refrigerant discharge port 24 communicates with the high-pressure chamber 17 via the discharge valve 18, and discharges the high-pressure refrigerant RH compressed by the inner compression unit 41 to the outside via the high-pressure refrigerant discharge pipe L3.

Here, since the refrigerant circulation amount of the suction inner compression portion 41 is larger than the refrigerant circulation amount of the suction outer compression portion 40, as shown in fig. 5, the height h2 of the fixed scroll plate-like wrap 31 and the orbiting scroll plate-like wrap 33 forming the inner compression portion 41 is made higher than the height h1 of the fixed scroll plate-like wrap 30 and the orbiting scroll plate-like wrap 32 forming the outer compression portion 40. The height h1, h2 can be adjusted to make the compression volume of the inner compression part 41 larger than that of the outer compression part 40. Thus, even if the intermediate-pressure refrigerant expanded in the high-stage expansion valve is introduced into the high-stage compression mechanism and the refrigerant circulation amount introduced into the high-stage compression mechanism is larger than the refrigerant circulation amount introduced into the low-stage compression mechanism, the apparatus can be downsized with a simple configuration.

As shown in fig. 5, tip seals 51 and 52 are provided on the tip side of the fixed scroll wrap 11b and the tip side of the orbiting scroll wrap 12b, respectively, to prevent the refrigerant from leaking between the outside and the inside of the fixed scroll wrap 11b and the refrigerant from leaking between the outside and the inside of the orbiting scroll wrap 12b when compressed by the outer compression part 40 and the inner compression part 41.

[ second embodiment ]

(application of asymmetric scroll compressor configuration)

As shown in fig. 8, in the scroll compressor 2 according to the second embodiment, the winding end position PB10 of the fixed scroll 11 and the winding end position PB11 of the orbiting scroll 12 are arranged symmetrically with respect to the center (the position of the high-pressure refrigerant discharge port 24).

Therefore, as shown in fig. 8 (a), in the outer compression portion 40, the low-pressure refrigerant RL initially forms a first inner compression chamber 60-1 inside the orbiting scroll 12 and a first outer compression chamber 61-1 outside the orbiting scroll 12. On the other hand, after one revolution (360 °) of the orbiting scroll 12, the first inner compression chamber 60-1 becomes the second inner compression chamber 60-2 to be compressed, and the first outer compression chamber 61-1 becomes the second outer compression chamber 61-2 to be compressed. That is, the first inner compression room 60-1 and the first outer compression room 61-1 show the state before one rotation of the second inner compression room 60-2 and the second outer compression room 61-2, respectively.

Fig. 8 (b) is a state in which the orbiting scroll 12 has been orbiting by the communication angle θ a by which the second inner compression chamber 60-2 communicates with the intermediate-pressure refrigerant discharge port 23, from the state of fig. 8 (a). In this case, the intermediate-pressure refrigerant of the second inner compression chamber 60-2 is communicated with the intermediate-pressure refrigerant discharge port 23 and discharged while communicating with the first outer compression chamber 61-1 as indicated by arrow a1, causing the compressed intermediate-pressure refrigerant of the second inner compression chamber 60-2, which is relatively higher in pressure than the first outer compression chamber 61-1, to leak toward the first outer compression chamber 61-1. As a result, recompression loss occurs, and the compression efficiency is lowered.

Therefore, as shown in fig. 9, the winding end position PB20 of the fixed scroll 11 and the winding end position PB21 of the orbiting scroll 12 are preferably disposed asymmetrically with respect to the center (the position of the high-pressure refrigerant discharge port 24). Here, as shown in fig. 9, in the asymmetric scroll compressor, the winding end position PB10 of the fixed scroll 11 of the symmetric scroll compressor is extended so that the extension angle θ a from the winding end position PB10 is in the range of 0 ° < θ a ≦ 180 °. In fig. 9, a winding end position PB20 at which the extension angle θ a is 180 ° is set.

Here, each inner wall and each outer wall of the fixed scroll 11 and the orbiting scroll 12 form an involute curve LI. The involute curve LI is a plane curve whose normal is always tangent to a constant circle (base circle C). As shown in fig. 10, when the extension angle of the involute curve LI is θ (°) and the radius of the base circle C is R, the position PB (θ) on the involute curve LI is { PBx (θ), and PBy (θ) } is expressed by the following equation.

PBx(θ)＝R{cosθ+(θ×π/180)sinθ}

PBy(θ)＝R{sinθ-(θ×π/180)cosθ}

Therefore, when the stretching angle at the winding end position PB10 is θ 1 and the stretching angle at the winding end position PB20 is θ 2, the stretching angle θ a becomes θ a — θ 2 — θ 1. In other words, the winding end position PB20 extends from the winding end position PB10 by an amount corresponding to the extension angle θ a.

Fig. 9 is an asymmetric scroll compressor in which the winding end position PB20 of the fixed scroll 11 and the winding end position PB21 of the orbiting scroll 12 are arranged at the same angular position with respect to the symmetric scroll compressor shown in fig. 8 (a). In the configuration of the asymmetric scroll compressor described above, when the first inner compression chamber 60-1 and the first outer compression chamber 61-1 shown in fig. 8 (a) are formed, the outer compression chamber 61-0 before half rotation is already formed. The outer compression chamber 61-0 becomes the first outer compression chamber 61-1 after one rotation. That is, when the first inner compression chamber 60-1 is formed, the first outer compression chamber 61-1 has been compressed from a half period ago. Therefore, when the communication angle θ a shown in fig. 8 (b) is set, the pressure of the first outer compression chamber 61-1 is substantially the same as the pressure of the second inner compression chamber 60-2, and the amount of leakage of the intermediate-pressure refrigerant compressed in the second inner compression chamber 60-2 into the first outer compression chamber 61-1 is reduced. As a result, the recompression loss can be reduced, and the reduction in compression efficiency can be prevented.

Fig. 11 is a graph comparing pressure changes in the inner compression chamber and the outer compression chamber and a pressure difference at the communication angle θ a when the symmetric scroll compressor shown in fig. 8 and the asymmetric scroll compressor shown in fig. 9 are used. Characteristic curves L60-1, L60-2, L61-0, L61-1 and L61-2 show pressure changes in the first inner compression chamber 60-1, the second inner compression chamber 60-2, the outer compression chamber 61-0, the first outer compression chamber 61-1 and the second outer compression chamber 61-2, respectively. As shown in fig. 11b, in the asymmetric scroll compressor, since the outer compression chamber 61-0 serving as the first outer compression chamber 61-1 is compressed from the time of the rotation angle θ 1 before one rotation at the rotation angle of 0 °, the pressure in the first outer compression chamber 61-1 (rotation angle 0 °) is increased, and the pressure difference PR2 at the communication angle θ a is smaller by the pressure difference Δ PR than the pressure difference PR1 of the symmetric scroll compressor shown in fig. 11 a.

As a result, as shown in fig. 12, the recompression loss S2 of the asymmetric scroll compressor is smaller than the recompression loss S1 of the symmetric scroll compressor.

The structure of the asymmetric scroll compressor is not limited to the two-stage compression and two-stage expansion cycle described in the first embodiment, and may be applied to a two-stage compression and one-stage expansion cycle. Specifically, the height h2 of the fixed scroll plate-like wrap 31 and the orbiting scroll plate-like wrap 33 forming the inner compression part 41 may be made higher than the height h1 of the fixed scroll plate-like wrap 30 and the orbiting scroll plate-like wrap 32 forming the outer compression part 40.

[ third embodiment ]

(mechanism for preventing leakage of refrigerant)

Within the housing 10, an intermediate pressure chamber 16 has an intermediate pressure PM. When the pressure in the casing 10 is set to the intermediate pressure PM, the intermediate pressure PM is applied to the back surface of the orbiting scroll 12, so that the thrust load of the orbiting scroll 12 can be reduced, and the reliability of the scroll compressor 2 can be improved due to reduction of mechanical loss and suppression of friction of the thrust bearing 14.

However, as shown in fig. 13, since the orbiting scroll plate wrap 12b of the orbiting scroll 12 receives a load in the radial direction a2, the orbiting scroll 12 may be in a state of orbiting by orbital revolution with a slight inclination. In this case, a gap d is formed between the tip surface of the outer peripheral portion of the fixed scroll 11 on the orbiting scroll 12 side and the upper surface of the base plate 12a of the orbiting scroll 12. When the gap d is formed, the intermediate-pressure refrigerant RM in the intermediate pressure chamber 16 leaks to the outer compression portion 40 where the low-pressure refrigerant RL is compressed. The leakage of the intermediate-pressure refrigerant RM to the outer compression portion 40 reduces the compression efficiency of the outer compression portion 40.

As shown in fig. 14, the compression efficiency of the outer compression portion 40 decreases because the pressure of the outer compression portion 40 increases due to the increase in the intermediate pressure refrigerant RM of the outer compression portion 40, and the compression power increases by the amount of the region E10. Further, as shown in fig. 15, since the intermediate-pressure refrigerant having a higher temperature than the low-pressure refrigerant in the outer compression portion 40 leaks to the outer compression portion 40, the low-pressure refrigerant is heated as indicated by an arrow a10, and the intermediate-pressure refrigerant compressed in the outer compression portion 40 becomes higher in temperature than the ideal intermediate-pressure refrigerant as indicated by an arrow a 11. When the high-temperature intermediate-pressure refrigerant is introduced into the inner compression portion 41, the density of the intermediate-pressure refrigerant in the inner compression portion 41 decreases, and therefore the volumetric efficiency of the inner compression portion 41 decreases.

Therefore, in the third embodiment, as shown in fig. 13, an outer wall 11c having an コ -shaped axial cross section of the orbiting scroll 12 is formed on the fixed scroll 11, and an annular seal is provided on a sliding surface between a tip end surface of the outer wall 11c and the base plate 12a of the orbiting scroll 12. In fig. 16 and 17, the annular seal 70 is provided on the front end surface side of the outer wall 11 c.

As shown in fig. 18, the annular seal 70 may be provided on the base plate 12a side of the orbiting scroll 12. The shape of the annular seal 70 is not limited to a circular shape, and may be an elliptical shape, a polygonal shape, or the like depending on the use mode.

(thermal expansion absorbing part of annular seal)

The annular seal 70 is made of, for example, resin or metal. However, the annular seal 70 thermally expands due to a temperature increase accompanying the operation of the scroll compressor 2. In particular, the annular seal 70 has a longer circumferential length than the width and thickness, and is restrained in the groove by being extended in the circumferential direction during thermal expansion, so that thermal stress is generated, and there is a possibility that biting may occur due to axial deformation, and breakage may occur.

Therefore, the annular seal 70 is preferably provided with a thermal expansion absorbing portion that absorbs thermal expansion during thermal expansion. For example, as shown in fig. 19, a part of the annular seal 70 is provided with a split gap 71 as an amount of relief at the time of thermal expansion. The divided gap 71 in fig. 19 is inclined with respect to the axial direction of the orbiting scroll 12. Here, the circumferential width d10 of the dividing gap 71 is a value corresponding to the amount of thermal expansion during thermal expansion. Since the divided gaps 71 are restricted by the grooves, a plurality of divided gaps are preferably provided in the circumferential direction. By providing the dividing gap 71, it is possible to avoid biting at the time of thermal expansion and to reliably block refrigerant leakage.

As shown in fig. 20, a split gap 72 may be provided instead of the split gap 71. The dividing gap 72 is inclined with respect to the circumferential direction of the orbiting scroll 12 or the fixed scroll 11. Here, the circumferential width d20 of the dividing gap 72 is a value corresponding to the amount of thermal expansion during thermal expansion. Since the divided gaps 72 are restricted by the grooves, a plurality of the divided gaps are preferably provided in the circumferential direction. By providing the dividing gap 72, it is possible to avoid biting at the time of thermal expansion and to reliably block refrigerant leakage.

As shown in fig. 21, one or more space portions 73 may be provided between the outer peripheral surface 70a and the inner peripheral surface 70b of the annular seal 70 and formed in a region excluding the outer peripheral surface 70a and the inner peripheral surface 70b, without providing the dividing

gaps

71 and 72. The space portion 73 is crushed during thermal expansion to absorb the thermal expansion, thereby suppressing deformation of the outer shape of the annular seal 70, and more reliably blocking refrigerant leakage than an annular seal having a dividing gap.

The third embodiment can also be applied to a general scroll compressor other than the scroll compressor of two-stage compression shown in the first embodiment. For example, it can be applied to a scroll compressor of one-stage compression.

(example of application of thermal cycle)

In the first to third embodiments, the heat cycle system shown in fig. 1 and 2 is shown as an example of a heat cycle system using a two-stage compression and two-stage expansion cycle. However, the scroll compressor 2 shown in the first to third embodiments may be applied to a heat cycle system other than the heat cycle system shown in fig. 1 and 2.

For example, as shown in fig. 22 and 23, the subcooler 4 may be removed from the heat cycle system 1 shown in fig. 1.

As shown in fig. 24 and 25, in the heat cycle system of fig. 22 and 23, an internal heat exchanger 9 may be provided, and the internal heat exchanger 9 may exchange heat between the intermediate-pressure refrigerant RM2 separated by the gas-liquid separator 6 and the low-pressure refrigerant RL led out from the evaporator 8.

As shown in fig. 26 and 27, the heat cycle system of fig. 1 and 2 may be provided with an internal heat exchanger 9a, and the internal heat exchanger 9a may exchange heat between the high-pressure refrigerant RH before being introduced into the high-stage expansion valve 5 and the low-pressure refrigerant RL led out from the evaporator 8.

As shown in fig. 28 and 29, the gas-liquid separator 6 of the heat cycle system 1 shown in fig. 1 is removed, the high-pressure refrigerant RH discharged from the subcooler 4 is branched at a branch point PS, one of the branched high-pressure refrigerants RH is introduced into the intermediate expansion valve 5a and is decompressed and expanded, and the internal heat exchanger 9b that exchanges heat between the decompressed and expanded intermediate-pressure refrigerant and the other high-pressure refrigerant that is not decompressed and expanded is provided. The internal heat exchanger 9b heats the intermediate-pressure refrigerant subjected to pressure reduction and expansion using the heat of the other high-pressure refrigerant that has not been subjected to pressure reduction and expansion. The intermediate-pressure refrigerant is directly introduced into the high-stage side compression chamber of the scroll compressor 2. On the other hand, the high-pressure refrigerant that has passed through the internal heat exchanger 9b and has not been subjected to decompression expansion is introduced into the low-stage expansion valve 7, is subjected to decompression expansion, and becomes an intermediate-pressure refrigerant.

[ fourth embodiment ]

Next, a fourth embodiment will be described. Fig. 30 is a longitudinal sectional view showing the structure of the scroll compressor 102 according to the fourth embodiment. Fig. 31 is a perspective view of the scroll compressor 102 shown in fig. 30, as viewed obliquely from the right. Fig. 32 is a perspective view of the scroll compressor 102 shown in fig. 30 viewed from diagonally left. Fig. 33 is a perspective view of the refrigerant connection cover 100 shown in fig. 30 as viewed from the back side (Y direction). Fig. 34 is a front view of a state where the refrigerant connection cover 100 is attached. Fig. 35 is a front view of a state where the refrigerant connection cover 100 is attached.

In the first to third embodiments, the casing 10a forming the intermediate pressure chamber 16 and the high pressure chamber 17 covers the rear surface of the outside of the fixed scroll 11 and is connected to the casing 10 b. In contrast, as shown in fig. 30 to 35, in the fourth embodiment, the refrigerant connection cover 100 that forms the intermediate-pressure refrigerant chamber 116 and the high-pressure refrigerant chamber 117 is directly attached to the back surface of the fixed scroll 11 facing outward (Y direction), the intermediate-pressure refrigerant chamber 116 sucks the intermediate-pressure refrigerant RM1, RM3 and discharges the intermediate-pressure refrigerant RM4 obtained by merging the intermediate-pressure refrigerants RM1, RM3, and the high-pressure refrigerant chamber 117 sucks and discharges the high-pressure refrigerant RH. Further, an intermediate-pressure refrigerant chamber 116 and a high-pressure refrigerant chamber 117 formed between the refrigerant connection cover 100 and the fixed scroll 11 are sealed by O-rings or the like, respectively. The thrust bearing mechanism 114 includes three thrust bearing mechanisms and a rotation suppressing mechanism for the orbiting scroll 12, and is provided on the XZ plane. The refrigerant connection cap 100 is detachably mounted to the housing 10.

By directly attaching the refrigerant connection cover 100 to the fixed scroll 11, the refrigerant connection cover 100 can be detached independently of the housing 10 (housing 10c) constituted by the

housings

10c and 10d without being affected by the housing 10c, and maintenance and compactness can be achieved. As shown in fig. 30, the housing 10c is fixed to the fixed scroll 11, and the fixed scroll 11 constitutes a part of the housing 10. Further, since the refrigerant connection cover 100 does not need to have a function of a housing, many valves, openings, and piping peculiar to the two-stage compression can be integrated.

The intermediate-pressure refrigerant chamber 116 is formed such that the recess 105 on the fixed scroll 11 side and the recess 106 on the refrigerant connection cover 100 side face each other. Similarly, the high-pressure refrigerant chamber 117 is formed such that the recess 107 on the fixed scroll 11 side and the recess 108 on the refrigerant connection cover 100 side face each other. Further, the intermediate-pressure refrigerant compartment 116 and the high-pressure refrigerant compartment 117 are partitioned by a partition wall 101.

The recess 105 is formed with: an intermediate-pressure refrigerant discharge port 123 corresponding to the intermediate-pressure refrigerant discharge port 23 communicating with the outer compression portion 40, an intermediate-pressure refrigerant suction port 122 corresponding to the intermediate-pressure refrigerant suction port 22 communicating with the inner compression portion 41, and an outlet opening 151 communicating with the intermediate-pressure spill port 141 of the outer compression portion 40. On the other hand, an external intermediate-pressure refrigerant connection introduction port 126 is formed in the recess 106, and the external intermediate-pressure refrigerant connection introduction port 126 takes in the gaseous intermediate-pressure refrigerant RM1 taken in from the external gas-liquid separator 6.

As shown in fig. 30 to 32, intermediate-pressure refrigerant RM1 is introduced into casing 10d from outer intermediate-pressure refrigerant suction port 130 together with oil, and reaches casing intermediate-pressure refrigerant suction port 131 via the seal in casing 10. The intermediate shell refrigerant suction port 131 and the external intermediate refrigerant connection introduction port 126 are connected by an intermediate pipe LM. Therefore, the intermediate-pressure refrigerant RM1 sucked in from the shell intermediate-pressure refrigerant suction port 131 is introduced into the intermediate-pressure refrigerant chamber 116 through the external intermediate-pressure refrigerant connection introduction port 126. The intermediate pipe LM is a pipe for introducing the gas-phase intermediate refrigerant RM1 separated in the gas-liquid separator 6 into the intermediate refrigerant chamber 116 (see fig. 1), and is a pipe for passing a part of the intermediate refrigerant RM through the casing 10.

The intermediate-pressure refrigerant RM1 introduced into the intermediate-pressure refrigerant chamber 116 and the intermediate-pressure refrigerant RM3 discharged from the intermediate-pressure refrigerant discharge port 123 merge in the intermediate-pressure refrigerant chamber 116, and are discharged as the intermediate-pressure refrigerant RM4 from the intermediate-pressure refrigerant suction port 122 to the inner compression portion 41.

Further, the fixed scroll 11 is provided with a low-pressure refrigerant suction port 121 corresponding to the low-pressure refrigerant suction port 21, and the low-pressure refrigerant RL is sucked into the outer compression portion 40 through the low-pressure refrigerant suction port 121.

On the other hand, the recess 107 is formed with a high-pressure refrigerant discharge port 124 corresponding to the high-pressure refrigerant discharge port 24 and an outlet opening 152 communicating with the high-pressure spill hole 142 of the outer compression portion 40. In addition, a high-pressure refrigerant outlet 125 for discharging the high-pressure refrigerant RH in the high-pressure refrigerant chamber 117 to the outside is formed in the recess 108.

Further, a check valve V1 for preventing the backflow of the intermediate pressure refrigerant RM3 from the intermediate pressure refrigerant discharge port 123 to the outer compression part 40 is provided in the recess 105 of the intermediate pressure refrigerant chamber 116. In addition, a check valve V2 is provided in the recess 107 of the high-pressure refrigerant chamber 117, and this check valve V2 prevents the high-pressure refrigerant RH from flowing back from the high-pressure refrigerant discharge port 124 to the inner compression portion 41.

Further, an intermediate pressure relief valve V11 as an intermediate pressure relief element is provided in the recess 105 of the intermediate pressure refrigerant chamber 116 at the outlet opening 151 of the intermediate pressure relief hole 141 (see fig. 6 and 35) so as to suppress the refrigerant pressure in the outer compression portion 40 to the first predetermined pressure or less. In the recess 107 of the high-pressure refrigerant chamber 117, a high-pressure relief valve V12 as a high-pressure relief element is provided at the outlet opening 152 of the high-pressure relief hole 142 (see fig. 6 and 35) so as to suppress the refrigerant pressure in the inner compression portion 41 to a second predetermined pressure or lower.

An intermediate-pressure refrigerant discharge port 123, an intermediate-pressure refrigerant suction port 122, and a high-pressure refrigerant discharge port 124 are formed on the casing 10 side, and an intermediate-pressure refrigerant chamber 116 and a high-pressure refrigerant chamber 117 are formed by attaching a refrigerant connection cover 100 including an external intermediate-pressure refrigerant connection introduction port 126 and a high-pressure refrigerant discharge port 125 to the casing 10.

Further, the intermediate-pressure refrigerant suction port 122, the intermediate-pressure refrigerant discharge port 123, and the external intermediate-pressure refrigerant connection introduction port 126 communicate with the intermediate-pressure refrigerant chamber 116, and the high-pressure refrigerant discharge port 124 and the high-pressure refrigerant discharge port 125 communicate with the high-pressure refrigerant chamber 117. The intermediate-pressure refrigerant suction port 122 and the high-pressure refrigerant discharge port 124 are opened in the same direction as the intermediate-pressure refrigerant discharge port 123. The casing intermediate-pressure refrigerant suction port 131 opens in the same direction as the intermediate-pressure refrigerant discharge port 123, and discharges the intermediate-pressure refrigerant via the seal in the casing 10.

In addition, when the refrigerant connection cover 100 is removed, the above-described intermediate pressure relief valve V11, high pressure relief valve V12, check valve V1, and check valve V2 appear on the surface of the casing 10, and therefore, maintainability can be improved.

Here, the volume of the intermediate-pressure refrigerant chamber 116 is larger than the volume of the high-pressure refrigerant chamber 117. That is, since the intermediate-pressure refrigerants RM1, RM3, RM4 have a lower density and are more likely to cause pressure loss than the high-pressure refrigerant RH, the volume of the intermediate-pressure refrigerant chamber 116 is increased to reduce the pressure loss.

In fig. 30 to 35, the depth d1 of the intermediate-pressure refrigerant chamber 116 is made equal to the depth d2 of the high-pressure refrigerant chamber 117, and the cross-sectional area of the intermediate-pressure refrigerant chamber 116 is made larger than the cross-sectional area of the high-pressure refrigerant chamber 117, whereby the volume of the intermediate-pressure refrigerant chamber 116 is increased. Further, without being limited thereto, the volume of the intermediate-pressure refrigerant chamber 116 may be increased by making the depth d1 of the intermediate-pressure refrigerant chamber 116 deeper than the depth d2 of the high-pressure refrigerant chamber 117. In this case, since the pressure of the intermediate-pressure refrigerant is lower than the pressure of the high-pressure refrigerant, the thickness of the refrigerant connection cover 100 around the intermediate-pressure refrigerant chamber 116 can be reduced, and the depth d2 can be easily increased.

Further, when the volume of the intermediate-pressure refrigerant chamber 116 or the high-pressure refrigerant chamber 117 is changed, the volume of the intermediate-pressure refrigerant chamber 116 or the high-pressure refrigerant chamber 117 can be changed without changing the structure on the casing 10 side by controlling the volume (depth) of the recess 106 or the recess 108 formed on the refrigerant connection cover 100 side.

Further, the notch 140 provided in the refrigerant connection cover 100 is used for positioning when the refrigerant connection cover 100 is attached.

In addition, when heating is performed using the condenser 3, the heat cycle system is a heat pump system, and when cooling is performed using the evaporator 8, the heat cycle system is a normal refrigeration system.

The scroll compressor 2 is a two-stage compressor having the outer compression part 40 and the inner compression part 41, but is not limited thereto and may be a multi-stage compressor.

(symbol description)

1 Heat cycle System

2. 102 scroll compressor

3 condenser

4 subcooler

5 high-stage expansion valve

5a intermediate expansion valve

6 gas-liquid separator

7 low-stage expansion valve

8 evaporator

9. 9a, 9b internal heat exchanger

10. 10a, 10b, 10c, 10d housing

11 fixed scroll

11a, 12a substrate

11b fixed scroll plate-shaped scroll lap

11c outer wall

12 orbiting scroll

12b orbiting scroll plate scroll wrap

13 crankshaft

14 thrust bearing

15 balance weight

16 middle pressure chamber

17 high pressure chamber

18 discharge valve

20 dividing wall

21. 121 low-pressure refrigerant suction inlet

22. 122 middle-pressure refrigerant suction inlet (middle-pressure refrigerant outlet)

23. 123 intermediate pressure refrigerant outlet (intermediate pressure refrigerant inlet)

24. 124 high pressure refrigerant discharge port (high pressure refrigerant introduction port)

30. 31 fixed scroll plate-like wrap

32. 33 orbiting scroll plate scroll wrap

40 outer compression part

41 inner compression part

51. 52 tip seal

60-1 first inner compression chamber

60-12 second inner side compression chamber

61-0 outer compression chamber

61-1 first outside compression chamber

61-2 second outer compression chamber

70 annular seal

70a outer peripheral surface

70b inner peripheral surface

71. 72 division gap

73 space part

100 refrigerant connection cover

101 partition wall

105 to 108 recesses

116 intermediate pressure refrigerant chamber

117 high pressure refrigerant chamber

114 thrust bearing mechanism

125 high-pressure refrigerant outlet

126 external middle pressure refrigerant connection leading-in port

130 outer intermediate pressure refrigerant suction inlet

131 casing middle pressure refrigerant suction inlet

141 middle pressure overflow hole

142 high pressure overflow hole

151. 152 outlet opening

Direction of rotation of AL

d clearance

E cut region

GH. Circulating amount of GL or GM refrigerant

L1 low-pressure refrigerant suction pipe

L2 intermediate pressure refrigerant suction pipe

L3 high-pressure refrigerant discharge pipe

LM intermediate pipe

V1, V2 check valve

V11 middle pressure overflow valve (middle pressure overflow element)

V12 high pressure overflow valve (high pressure overflow element)

Angle of theta A connectivity

Claims

1. A multi-stage compressor comprising:

a plurality of compression chambers provided in the housing;

an intermediate-pressure refrigerant discharge port that discharges an intermediate-pressure refrigerant from a low-stage-side compression chamber of the plurality of compression chambers;

an intermediate-pressure refrigerant suction port that opens in the same direction as the intermediate-pressure refrigerant discharge port and that sucks the intermediate-pressure refrigerant into a high-stage-side compression chamber of the plurality of compression chambers;

a high-pressure refrigerant discharge port that opens in the same direction as the intermediate-pressure refrigerant discharge port and discharges a high-pressure refrigerant discharged from the high-stage-side compression chambers of the plurality of compression chambers; and

a refrigerant connection cover detachably mounted to a fixed scroll constituting a part of the casing, and forming an intermediate-pressure refrigerant chamber communicating with the intermediate-pressure refrigerant suction port and the intermediate-pressure refrigerant discharge port and including an external intermediate-pressure refrigerant connection introduction port opened to the outside, and a high-pressure refrigerant chamber communicating with the high-pressure refrigerant discharge port and including a high-pressure refrigerant lead-out port opened to the outside.

2. The multi-stage compressor of claim 1,

a shell intermediate-pressure refrigerant suction port that opens in the same direction as the intermediate-pressure refrigerant discharge port is formed in the shell, intermediate-pressure refrigerant is discharged via a seal in the shell,

the shell intermediate-pressure refrigerant suction port and the external intermediate-pressure refrigerant connection introduction port are connected by a pipe.

3. The multi-stage compressor of claim 1,

a high-pressure relief element is provided in the high-pressure refrigerant chamber of the casing, and the high-pressure relief element communicates the high-stage-side compression chamber with the high-pressure refrigerant chamber when the internal pressure of the high-stage-side compression chamber is equal to or higher than a predetermined value.

4. The multi-stage compressor of claim 1,

an intermediate pressure relief element is provided in the intermediate-pressure refrigerant chamber of the casing, and the intermediate pressure relief element communicates the low-stage-side compression chamber with the intermediate-pressure refrigerant chamber when the internal pressure of the low-stage-side compression chamber is equal to or higher than a predetermined value.

5. The multi-stage compressor of claim 1,

a check valve for preventing backflow from the intermediate-pressure refrigerant discharge port to the low-stage-side compression chamber is provided in the intermediate-pressure refrigerant chamber of the casing.

6. The multi-stage compressor of claim 1,

a check valve for preventing backflow from the high-pressure refrigerant discharge port to the high-stage-side compression chamber is provided in the high-pressure refrigerant chamber of the housing.

7. The multi-stage compressor of claim 1,

the multi-stage compressor is a scroll compressor including an orbiting scroll and a fixed scroll,

the fixed scroll constitutes a part of the casing, and is mounted with the refrigerant connection cap.

8. The multi-stage compressor of claim 1,

the volume of the intermediate-pressure refrigerant chamber is larger than the volume of the high-pressure refrigerant chamber.

9. The multi-stage compressor of claim 1,

the refrigerant connection cover is provided with a notch for positioning.

10. A multi-stage compressor is composed of a compressor body with multiple stages,

use of a multistage compressor according to any one of claims 1 to 9 in a two-stage compression two-stage expansion heat cycle system.