JP7430759B2 - Accumulator and refrigeration cycle - Google Patents

Description

The present invention relates to an accumulator and a refrigeration cycle.

Refrigeration equipment often uses an accumulator to perform gas-liquid separation of refrigerant so that liquid refrigerant is not supplied to the compressor.
Patent Document 1 describes an accumulator for a refrigeration device. In Patent Document 1, one accumulator is provided for a plurality of compressors. The accumulator described in Patent Document 1 includes U-shaped tubes each connected to a plurality of compressors. These plurality of U-shaped tubes are housed in one container. In the accumulator of Patent Document 1, a refrigerant is introduced from an inlet pipe connected to the upper part of the container. Among the refrigerants introduced from this inlet pipe, liquid refrigerant moves downward due to its own weight and accumulates at the bottom of the container. On the other hand, the gaseous refrigerant is discharged from the accumulator from the suction port of the U-shaped tube disposed in the upper part of the container through the flow path in the U-shaped tube.

Patent No. 4442384

When the refrigerant is introduced from the inlet pipe connected to the upper part of the container as in the accumulator described in Patent Document 1, the refrigerant in a gas-liquid mixed state that flows from the inlet pipe hits the inner wall surface of the container and the U-shaped pipe. It may collide with the supporting bracket. When the refrigerant collides with the inner wall surface, brackets, etc. in this way, the liquid refrigerant scatters due to its rebound and enters the inside of the U-shaped tube from the suction port of the U-shaped tube, and is then discharged from the accumulator. It may be stored away.

This invention has been made in view of the above circumstances, and provides an accumulator and a refrigeration cycle that can improve the efficiency of gas-liquid separation.

In order to solve the above problems, the following configuration is adopted.
An accumulator according to one aspect of the present invention includes a container having an internal space for separating refrigerant into gas and liquid; a U-shaped tube having a straight tube section in the upper part of the container, and a bent tube section arranged outside the container so as to be folded upward from the lower end of the straight tube section; an inlet pipe provided with an injection port for injecting a refrigerant into the interior of the container, the container has a tubular shape extending in the vertical direction, the through hole is formed at an upper end and a lower end of the container, The straight pipe part is fixed around the through hole in the upper end part and the through hole in the lower end part, respectively, and the U-shaped pipe is fixed at the uppermost part of the downstream side of the bent pipe part and the uppermost part of the straight pipe part. The suction port has a pressure equalizing pipe arranged outside the container , which communicates with the top part arranged outside the container , and the suction port is connected to the center of the injection port and the straight pipe when viewed from the top and bottom. or located on the opposite side of a first imaginary straight line extending in the direction in which the refrigerant is injected from the injection port across a second imaginary straight line passing through the center of the part, or above the injection port in the vertical direction. It is located in

A refrigeration cycle according to one aspect of the present invention includes a circulation line through which a refrigerant flows, the accumulator that separates the refrigerant into gas and liquid, a compressor, a first heat exchanger, a second heat exchanger, and an expansion valve. We are prepared. A compressor compresses the gaseous refrigerant separated by the accumulator. The first heat exchanger is disposed in the circulation line, and exchanges heat between the refrigerant flowing through the circulation line and the first medium to change the phase of the refrigerant. The second heat exchanger is disposed in the circulation line, and exchanges heat between the refrigerant flowing through the circulation line and a second medium to change the phase of the refrigerant. Among the circulation lines between the first heat exchanger and the second heat exchanger, the compressor is disposed in the circulation line where the compressor is not disposed.

According to the above accumulator and refrigeration cycle, the efficiency of gas-liquid separation can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the schematic structure of the refrigeration cycle in embodiment of this invention. FIG. 1 is a perspective view showing a schematic configuration of an accumulator in an embodiment of the invention. FIG. 3 is a vertical cross-sectional view of the upper part of the accumulator in the embodiment of the present invention. FIG. 3 is a horizontal cross-sectional view of the vicinity of the inlet pipe of the accumulator in the embodiment of the present invention.

Next, an accumulator and a refrigeration cycle in an embodiment of the present invention will be explained based on the drawings.
FIG. 1 is a configuration diagram showing a schematic configuration of a refrigeration cycle in an embodiment of the present invention.
As shown in FIG. 1, the refrigeration cycle 100 of this embodiment includes a circulation line 10, an accumulator 5, a compressor 60, a first heat exchanger 1, a second heat exchanger 2, an expansion valve 3, A four-way switching valve 4 is provided. The refrigeration cycle 100 of this embodiment can be used, for example, in a refrigeration unit for land transportation (also referred to as a land reflex unit). In the following explanation, a case will be described in which the first heat exchanger 1 normally functions as a condenser and the second heat exchanger 2 functions as an evaporator. The function of the first heat exchanger and the function of the second heat exchanger may be switched.

The circulation line 10 forms a flow path through which the refrigerant R circulates. The circulation line 10 connects the accumulator 5, the compressor 60, the first heat exchanger 1, the expansion valve 3, the second heat exchanger 2, and the four-way switching valve 4.

The accumulator 5 has a function of temporarily storing the refrigerant R and separating the refrigerant R in the liquid phase (hereinafter simply referred to as liquid refrigerant RL) and the refrigerant R in the gas phase (hereinafter simply referred to as gas refrigerant RG). has. This accumulator 5 separates the refrigerant R in a gas-liquid mixed state from the refrigerant inlet 5a into gas and liquid, and discharges the gas refrigerant RG from the refrigerant outlet 5b.

The compressor 60 compresses the gas refrigerant RG discharged from the refrigerant outlet 5b of the accumulator 5. The compressor 60 compresses the gas refrigerant RG that has flowed in from the suction port 65 and discharges it from the discharge port 66 . The gaseous refrigerant RG compressed by the compressor 60 is supplied to the first heat exchanger 1 via the first port 4a and the second port 4b of the four-way switching valve 4.

The first heat exchanger 1 exchanges heat between the compressed gas refrigerant RG and the first medium M1 to change the phase of the gas refrigerant RG. More specifically, since the first heat exchanger 1 normally functions as a condenser, it exchanges heat between the gaseous refrigerant RG compressed by the compressor 60 and the outside air. The first heat exchanger 1 removes heat from the gaseous refrigerant RG that has flowed in from the first refrigerant port 1a, condenses it, and discharges the condensed liquid refrigerant RL from the second refrigerant port 1b.

The expansion valve 3 adiabatically expands the liquid refrigerant RL. More specifically, the expansion valve 3 adiabatically expands the liquid refrigerant RL discharged from the second refrigerant port 1b of the first heat exchanger 1 and sends it to the second heat exchanger 2.

The second heat exchanger 2 exchanges heat between the adiabatically expanded liquid refrigerant RL (refrigerant R) and the second medium M2 to change the phase of the liquid refrigerant RL. More specifically, since the second heat exchanger 2 normally functions as an evaporator, it exchanges heat between the liquid refrigerant RL adiabatically expanded by the expansion valve 3 and the air to be cooled indoors. . The second heat exchanger 2 heats and evaporates the liquid refrigerant RL that has flowed in from the first refrigerant port 2a, and generates a refrigerant R in a gas-liquid mixed state of the evaporated gas refrigerant RG and the unevaporated liquid refrigerant RL. It is discharged from the second refrigerant port 2b. The refrigerant R discharged from the second heat exchanger 2 is supplied to the accumulator 5 via the fourth port 4d and the third port 4c of the four-way switching valve 4.

The four-way switching valve 4 has four ports: a first port 4a, a second port 4b, a third port 4c, and a fourth port 4d. The four-way switching valve 4 is capable of selectively changing the communication state between each port. Specifically, the four-way switching valve 4 of this embodiment can select either the first connection form or the second connection form. The first connection form allows the first port 4a and the second port 4b to communicate with each other, and also allows the third port 4c and the fourth port 4d to communicate with each other. The second connection form allows the second port 4b and the third port 4c to communicate with each other, and also allows the fourth port 4d and the first port 4a to communicate with each other. That is, according to the four-way switching valve 4, by switching between the first connection form and the second connection form, it is possible to reverse the direction of the refrigerant R flowing into the circulation line 10, and as a result, the direction of the refrigerant R flowing in the circulation line 10 can be reversed. The function of the heat exchanger 1 and the function of the second heat exchanger 2 can be interchanged.

FIG. 2 is a perspective view showing a schematic configuration of an accumulator in an embodiment of the invention. As shown in FIG. 2, the accumulator 5 includes a container 21, a U-shaped tube 22, and an inlet tube 24. The container 21 has an internal space S1 that separates the refrigerant R supplied from the first heat exchanger 1 or the second heat exchanger 2, which functions as an evaporator, into gas and liquid. The container 21 exemplified in this embodiment includes a cylindrical body 21A and two end plate portions 21B that close both ends of the body 21A. This container 21 is arranged, for example, adjacent to the compressor 60, with the axis O1 of the body 21A extending in the vertical direction (more specifically, in the vertical direction). In addition, although this embodiment illustrates the case where the end plate part 21B has a spherical surface, the shape of the end plate part 21B is not limited to this shape.

The U-shaped pipe 22 forms a flow path for discharging the gas refrigerant RG out of the gas-liquid separated refrigerant R. The U-shaped tube 22 includes a straight tube section 26 and a curved tube section 27.
The straight pipe portion 26 is formed into a tubular shape with a circular cross section (in other words, a circular tubular shape) that extends in the vertical direction inside the internal space S1. The straight pipe portion 26 has a suction port 28 at the top that takes in the gas refrigerant RG in the internal space S1. The suction port 28 in this embodiment is formed in an elliptical shape that is elongated in the vertical direction.

The bent pipe portion 27 is formed into a U-shape so as to be folded upward from the lower end of the straight pipe portion 26 . The curved pipe section 27 is arranged outside the container 21, and the straight pipe section 26 passes through the container 21 vertically. The upper and lower parts of the straight pipe section 26 are supported by the container 21, respectively. Specifically, the upper and lower parts of the straight pipe part 26 are each fixed to the periphery of the through hole of the container 21 via a welded part M by brazing or the like. The straight pipe portion 26 is arranged so that its central axis overlaps the axis O1 of the container 21. Note that the upper end of the straight pipe portion 26 is closed.

FIG. 3 is a longitudinal sectional view of the upper part of the accumulator in the embodiment of the invention. FIG. 4 is a horizontal sectional view of the vicinity of the inlet pipe of the accumulator in the embodiment of the present invention.
As shown in FIGS. 3 and 4, the inlet pipe 24 has an injection port 33 that injects the refrigerant R into the interior of the container 21. As shown in FIGS. This injection port 33 is arranged below the suction port 28. In other words, the suction port 28 is arranged above the injection port 33. The inlet pipe 24 in this embodiment is formed into a circular tube shape. The injection port 33 in this embodiment is arranged at the same position (in other words, flush) with the inner wall surface 21i of the container 21 in the radial direction of the body 21A.

As shown in FIG. 4, a straight line extending in the direction in which the refrigerant R is injected from the center of the injection port 33 when viewed from the vertical direction (in other words, the direction in which the axis O1 extends) is defined as a first virtual straight line IL1. Furthermore, a straight line passing through the center of the injection port 33 and the center of the straight pipe portion 26 (in other words, the axis O1) is defined as a second virtual straight line IL2. Then, the first imaginary straight line IL1 in this inlet pipe 24 is inclined with respect to the second imaginary straight line IL2. Note that the closer the first virtual straight line IL1 approaches the inclination angle of the tangent to the container 21 at the position of the injection port 33 in the cross-sectional view of FIG. 4, the more smoothly the refrigerant R injected from the injection port 33 can be turned. becomes.

In this embodiment, a case is illustrated in which the first imaginary straight line IL1 passes through a position where it does not contact the outer circumferential surface 26o of the straight pipe portion 26. By arranging the inlet pipe 24 in this way, the refrigerant R injected from the injection port 33 is directed into the cylindrical internal space formed between the outer peripheral surface 26o of the straight pipe section 26 and the inner wall surface 21i of the container 21. S1 becomes a swirling flow that swirls around the straight pipe portion 26. Note that the diameter of the injection port 33 should just be large enough to obtain the flow velocity necessary for the swirling flow. In the embodiment described above, the case where the diameter of the inlet pipe 24 and the diameter of the injection port 33 are made the same is illustrated, but the diameter of the injection port 33 may be smaller than the diameter of the inlet pipe 24.

The suction port 28 is disposed on the opposite side of the first imaginary straight line IL1 with the second imaginary straight line IL2 in between, when viewed from the direction of the axis O1. The suction port 28 in this embodiment is arranged on a third imaginary straight line IL3 that passes through the axis O1 and an intersection P1 between the first imaginary straight line IL1 and the inner wall surface 21i of the container 21, when viewed from the direction of the axis O1.

As shown in FIG. 2, the U-shaped pipe 22 in this embodiment has a pressure equalizing pipe 35 that connects the uppermost part of the downstream side of the curved pipe part 27 and the uppermost part of the straight pipe part 26. This pressure equalizing pipe 35 is formed to have a smaller diameter than the U-shaped pipe 22. This pressure equalization pipe 35 prevents a pressure difference from occurring between the internal space S1 of the container 21 and the outlet of the U-shaped pipe 22 even after the refrigeration cycle 100 is stopped.
Further, the straight pipe portion 26 in this embodiment has an oil return hole 36 at the lowest part within the container 21. The oil return hole 36 is capable of introducing a liquid refrigerant RL containing lubricating oil stored in the lower part of the container 21 into the U-shaped tube 22 .

In this embodiment, the straight pipe portion 26 passes through the container 21 in the vertical direction. Therefore, the upper and lower parts of the straight tube section 26 are supported by the container 21. Therefore, it is possible to omit the bracket required when all the U-shaped tubes 22 are arranged inside the container.
Therefore, it is possible to suppress the liquid refrigerant RL from entering the suction port 28 due to the refrigerant R colliding with the bracket supporting the U-shaped tube and scattering.

In this embodiment, the first imaginary straight line IL1 is further inclined with respect to the second imaginary straight line IL2 when viewed from the axis O1 direction. Therefore, the refrigerant R injected from the injection port 33 swirls around the straight pipe portion 26. Due to the centrifugal force caused by this swirling and the density difference between the gas refrigerant RG and the liquid refrigerant RL, the liquid refrigerant RL swirls on the outside of the gas refrigerant RG and adheres to the inner wall surface 21i of the container 21, and the inside of the container 21 is caused by gravity. It flows down along the wall surface 21i.

In this embodiment, the curved pipe section 27 is arranged outside the container 21, and only the straight pipe section 26 is arranged inside the container 21. Therefore, the center of rotation of the refrigerant R becomes a straight line extending in the vertical direction. Therefore, compared to the case where the curved tube section 27 is arranged inside the container 21, it is possible to suppress the rotation of the refrigerant R from being inhibited by the bracket or the curved tube section 27.
Therefore, it is possible to improve the efficiency of gas-liquid separation.

In this embodiment, the body portion 21A of the container 21 is further formed to have a circular cross section, and the straight tube portion 26 is also formed to have a circular tube shape. The inner wall surface 21i of the trunk portion 21A and the outer circumferential surface 26o of the straight pipe portion 26 are arranged on concentric circles centered on the axis O1. Therefore, the flow path around the straight pipe portion 26 through which the swirling flow flows has a constant flow path width in the circumferential direction. Furthermore, since the body portion 21A is formed to have a circular cross section and the straight tube portion 26 is formed to have a circular tube shape, no corners or the like are formed in the flow path.
Therefore, it becomes possible to swirl the refrigerant R smoothly, and the efficiency of gas-liquid separation can be further improved.

In this embodiment, the suction port 28 is further arranged on the opposite side of the first imaginary straight line IL1 across the second imaginary straight line IL2. Therefore, the refrigerant R does not collide with the container 21 or the straight pipe portion 26 near the suction port 28. When the refrigerant R collides with the inner wall surface 21i of the container 21, the colliding surface of the refrigerant R and the suction port 28 are not arranged to face each other. Therefore, even if the refrigerant R injected from the injection port 33 collides with the inner wall surface 21i of the container 21 or the outer circumferential surface 26o of the straight pipe section 26 and scatters, the liquid refrigerant RL flows from the suction port 28 into the inside of the straight pipe section 26. can be prevented from directly entering the

In this embodiment, the suction port 28 is further arranged above the injection port 33 in the direction of the axis O1. Therefore, even if the refrigerant R injected from the injection port 33 collides with the inner wall surface 21i of the container 21 or the outer circumferential surface 26o of the straight pipe section 26 and scatters, it will immediately head downward due to gravity, so that the collision position of the refrigerant R is lower than the collision position. It is possible to suppress liquid refrigerant from entering the inside of the straight pipe portion from the suction port 28 disposed above.

The refrigeration cycle 100 of this embodiment includes the accumulator 5 configured as described above. Therefore, the efficiency of gas-liquid separation of the refrigerant R by the accumulator 5 can be improved. Therefore, the supply of liquid refrigerant RL to the compressor 60 can be suppressed without increasing the size of the accumulator 5, and the reliability of the refrigeration cycle 100 can be improved.

(Other variations)
This invention is not limited to the embodiments described above, but includes various modifications to the embodiments described above without departing from the spirit of the invention. That is, the specific shapes, configurations, etc. mentioned in the embodiments are merely examples, and can be changed as appropriate.
For example, in the embodiment described above, the case where the suction port 28 is formed in an ellipse has been described. However, the shape of the suction port 28 is not limited to an ellipse, and may be other shapes such as a circle, an oval, or a rectangle.

In the above-described embodiment, the case where the cross-sectional shapes perpendicular to the axis O of the straight pipe portion 26 and the body portion 21A of the container 21 are both circular. However, the cross-sectional shapes of the straight pipe portion 26 and the body portion 21A are not limited to circular shapes. For example, it may have a polygonal shape.

In the embodiment described above, a case has been described in which the central axis of the straight pipe portion 26 is arranged on the axis O, but the present invention is not limited to this configuration.

In the embodiment described above, the injection port 33 is arranged at the same position as the inner wall surface 21i of the container 21 in the radial direction of the body 21A. However, the injection port 33 may be arranged so as to protrude further inward in the radial direction than the inner wall surface 21i of the container 21.

1...First heat exchanger 1a...First refrigerant port 1b...Second refrigerant port 2...Second heat exchanger 2a...First refrigerant port 2b...Second refrigerant port 3...Expansion valve 4...Four-way switching valve 4a...Second refrigerant port 1 port 4b...Second port 4c...Third port 4d...Fourth port 5...Accumulator 5a...Refrigerant inlet 5b...Refrigerant outlet 10...Circulation line 21...Container 21A...Body part 21B...End plate part 21i...Inner wall surface 22...U Shape tube 24...Inlet pipe 26...Straight pipe part 26o...Outer circumferential surface 27...Bent pipe part 28...Suction port 33...Injection port 35...Pressure equalization pipe 36...Oil return hole 60...Compressor 65...Suction port 66...Discharge port 100... Refrigeration cycle IL1...first virtual straight line IL2...second virtual straight line IL3...third virtual straight line

Claims (5)

a container having an internal space for separating refrigerant into gas and liquid;
a straight pipe portion that vertically penetrates the container through a through hole in the container and has a suction port at the top of the internal space for taking in a gaseous refrigerant; and a lower end of the straight pipe portion that is disposed outside the container. a U-shaped pipe having a bent pipe part formed to be folded upward from the part;
an inlet pipe equipped with an injection port for injecting refrigerant into the interior of the container;
Equipped with
The container has a tubular shape extending in the vertical direction,
The through hole is formed at an upper end and a lower end of the container,
The straight pipe portion is fixed around the through hole in the upper end portion and the through hole in the lower end portion, respectively,
The U-shaped pipe communicates the uppermost part of the curved pipe part on the downstream side and the uppermost part of the straight pipe part located outside the container , and connects the pressure equalizing pipe located outside the container. have ,
The suction port is
When viewed from above and below, disposed on the opposite side of a first imaginary straight line extending in a direction in which the refrigerant is injected from the injection port, across a second imaginary straight line passing through the center of the injection port and the center of the straight pipe portion. or is located above the injection port in the vertical direction
accumulator. The accumulator according to claim 1, wherein the straight pipe portion is fixed around the through hole via a welded portion. The container is
A cylindrical body,
two end plate parts that close both ends of the body part,
The accumulator according to claim 1 or 2, wherein the through hole is formed in the end plate. The container is
A body portion having an axis extending in the vertical direction and having an inner wall surface having a circular cross section centered on the axis,
The accumulator according to claim 1 or 2, wherein the straight tube portion is formed in a circular tube shape centered on the axis. A circulation line through which refrigerant flows,
The accumulator according to any one of claims 1 to 4 , which separates the refrigerant into gas and liquid.
a compressor that compresses the gaseous refrigerant separated by the accumulator;
a first heat exchanger that is disposed in the circulation line and exchanges heat between the refrigerant flowing through the circulation line and a first medium to change the phase of the refrigerant;
a second heat exchanger that is disposed in the circulation line and exchanges heat between the refrigerant flowing through the circulation line and a second medium to change the phase of the refrigerant;
an expansion valve disposed in the circulation line between the first heat exchanger and the second heat exchanger on the side where the compressor is not disposed;
A refrigeration cycle equipped with

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