EP2910875B1

EP2910875B1 - Oil separator

Info

Publication number: EP2910875B1
Application number: EP15153295.9A
Authority: EP
Inventors: Osamu Ogawa; Satoshi Imai
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2014-02-13
Filing date: 2015-01-30
Publication date: 2024-03-06
Anticipated expiration: 2035-01-30
Also published as: KR20150095550A; CN104848615B; CN104848615A; KR102183547B1; EP2910875A1; JP2015166668A; JP6403061B2

Description

BACKGROUND

1. Technical Field

The present invention relates to an oil separator that separates refrigerating machine oil by inertia force and centrifugal force, from a gas phase refrigerant containing the refrigerating machine oil that is discharged from a compressor.

2. Description of the Related Art

A compressor is used for a heat pump cycle of an air conditioner and the like. To lubricate sliding portions of the compressor, refrigerating machine oil is typically used. The refrigerating machine oil circulates through a refrigerant circulating system with a refrigerant flowing through the refrigerant circulating system.
Then, the refrigerating machine oil suctioned from an intake side of the compressor or the refrigerating machine oil stored in a shell container including the compressor is supplied to the sliding portions inside the compressor and used to lubricate the sliding portions. In addition, the refrigerating machine oil is supplied to an operation chamber of the compressor and used to prevent leakage of a vaporized refrigerant by sealing a gap inside the operation chamber.
In the above refrigerant circulating system, if the refrigerant discharged from the compressor contains a large amount of refrigerating machine oil, the refrigerating machine oil tends to attach to an inner wall of a heat transfer pipe of a heat exchanger. The refrigerating machine oil attaching to the inner wall of the heat transfer pipe is a factor that hampers heat transfer in the heat transfer pipe, worsens the heat-transfer efficiency of the heat exchanger, and increases pressure loss.
To avoid such a situation, an oil separator is provided inside the refrigerant circulating system. The oil separator separates the refrigerating machine oil from the refrigerant discharged from the compressor, and returns the refrigerating machine oil to the intake side of the compressor.
Conventionally, as described in Japanese Unexamined Patent Application Publication No. 11-173706 , an oil separator is known which is provided with a refrigerant inlet pipe and a refrigerant outlet pipe in an upper end plate of a pressure container, and is provided with an oil return pipe in a lower end plate of the pressure container.
After a mixture of a gas phase refrigerant and refrigerating machine oil from a compressor flows in trough the refrigerant inlet pipe, the oil separator causes the mixture to collide against a cylindrical inner wall of the pressure container and separates the refrigerating machine oil by inertia force. Then, after the mixture of the gas phase refrigerant and refrigerating machine oil collides against the inner wall, the oil separator causes the mixture to rotate at a high speed along the inner wall and separates the refrigerating machine oil by centrifugal force.
Document JP-H09-210509 discloses an oil separator that separates refrigerating machine oil contained in a gas phase, according to the preamble of claim 1.

SUMMARY

However, there is room for improvement in the oil separator described in Japanese Unexamined Patent Application Publication No. 11-173706 above.
Such an improvement is provided by the oil separator according to claim 1.
One non-limiting and exemplary embodiment provides an improved oil separator according to claim 1.
Additional benefits and advantages of the disclosed embodiments will be apparent from the specification and Figures. The benefits and/or advantages may be individually provided by the various embodiments and features of the specification and drawings disclosure, and need not all be provided in order to obtain one or more of the same.
The oil separator according to the present invention, separates refrigerating machine oil contained in a gas phase refrigerant by inertia force and centrifugal force. The oil separator includes a cylindrical pressure container, a refrigerant inlet pipe that leads the gas phase refrigerant containing the refrigerating machine oil into the cylindrical pressure container, and a refrigerant outlet pipe that discharges the gas phase refrigerant from which the refrigerating machine oil is separated. An angle α between a straight line along the direction of the opening of a delivery port at a tip of the refrigerant inlet pipe introduced into the cylindrical pressure container and a plane perpendicular to the central axis of the cylindrical pressure container satisfies 45° ≤ α < 90°.
The present invention can reduce an influence of variations in the machining accuracy of the refrigerant inlet pipe of the oil separator, enhance an effect of impingement separation and an effect of centrifugal separation for the refrigerating machine oil at the same time, and make a path length of a rotational flow longer than a conventional one.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a refrigerant circuit diagram illustrating an overall configuration of an outdoor unit of an air conditioner according to an embodiment of the present disclosure;
Fig. 2 illustrates an inside of an oil separator according to the present invention, when the oil separator is viewed from the upper direction;
Fig. 3 illustrates the inside of the oil according to the present invention, when the oil separator is viewed from the direction of arrow III in Fig. 2;
Fig. 4 illustrates the inside of the oil according to the present invention, when the oil separator is viewed from the direction of arrow IV in Fig. 2;
Fig. 5 illustrates an influence of a position of a delivery port of a refrigerant inlet pipe on a separation rate of refrigerating machine oil;
Fig. 6 is a streamline diagram illustrating an example of a flow of a gas phase refrigerant; and
Fig. 7 illustrates a configuration of a conventional oil separator.

DETAILED DESCRIPTION

The inventor has conducted a thorough study of the conventional oil separator and has obtained the following knowledge.
In the oil separator described in Japanese Unexamined Patent Application Publication No. 11-173706 above, the refrigerant inlet pipe is introduced through the upper end plate of the pressure container. A delivery port of the refrigerant inlet pipe is curved, and the direction of the opening of the delivery port is faced toward a portion of the inner wall of the oil separator slightly below the delivery port. A gas phase refrigerant delivered from the delivery port collides against the inner wall of the pressure container and rotates within the pressure container.
However, there are variations in the machining accuracy with which the delivery port of the refrigerant inlet pipe is curved. Therefore, such an oil separator has a problem in that there are individual differences in the direction of a rotational flow of the gas phase refrigerant inside the pressure container.
Such an oil separator has another problem in that it is difficult to improve an effect of impingement separation and an effect of centrifugal separation for refrigerating machine oil at the same time. Fig. 7 illustrates a configuration of a conventional oil separator 1. Fig. 7 is a cross sectional view of the oil separator 1 including a cylindrical pressure container 20 when the oil separator 1 is cut by a plane perpendicular to the central axis of the pressure container 20.
The oil separator 1 includes the pressure container 20, a refrigerant inlet pipe 11, and a refrigerant outlet pipe 14. As described above, the direction of the opening of a delivery port 13 is faced toward a portion of the inner wall of the oil separator 1 slightly below the delivery port 13.
In Fig. 7, it is desirable that a distance X is large to some extent and a distance Y is small. The distances X and Y are distances from the delivery port 13 to the inner wall of the oil separator 1 in the direction of the opening and in a direction perpendicular to the direction of the opening, respectively.
If the distance X is made larger, because a flow of the gas phase refrigerant flowing into the pressure container 20 through the delivery port 13 is diffused, the refrigerating machine oil attaches to the inner wall easily. Therefore, a high effect of impingement separation by inertia force is obtained.
If the distance Y is made smaller, when the gas phase refrigerant rotates along the inner wall and the refrigerating machine oil is separated by centrifugal force, the time required for the refrigerating machine oil to reach the inner wall is shortened. Therefore, a high effect of centrifugal separation by centrifugal force is obtained.
However, in the above oil separator 1, there is a tradeoff relationship between making the distance X larger and making the distance Y smaller. That is, even if a position of the delivery port 13 is adjusted within a horizontal plane, when the distance X is made larger, the distance Y is also made larger; and conversely, when the distance Y is made smaller, the distance X is also made smaller. It is therefore difficult to enhance an effect of impingement separation and an effect of centrifugal separation at the same time.
Moreover, in the oil separator 1, because the direction of the opening of the delivery port 13 is faced toward a portion of the inner wall of the oil separator 1 slightly below the delivery port 13, the rotational flow of the gas phase refrigerant reaches a bottom part of the pressure container 20 quickly and the path length of the rotational flow is shortened. Therefore, the refrigerating machine oil may not be separated sufficiently.
The inventor has thus conceived the following oil separator.
The oil separator of the present invention separates refrigerating machine oil contained in a gas phase refrigerant. The oil separator includes a cylindrical pressure container, a refrigerant inlet pipe that leads the gas phase refrigerant containing the refrigerating machine oil into the cylindrical pressure container, and a refrigerant outlet pipe that discharges the gas phase refrigerant from which the refrigerating machine oil is separated. An angle α between a straight line along the direction of the opening of a delivery port at a tip of the refrigerant inlet pipe introduced into the cylindrical pressure container and a plane perpendicular to the central axis of the cylindrical pressure container satisfies 45° ≤ α < 90°.
This prevents the direction of the opening of the delivery port from facing further downward than a horizontal direction due to variations in the machining accuracy of the refrigerant inlet pipe of the oil separator. Because the direction of the opening of the delivery port faces upward, a rotational flow going through an upper part of the cylindrical pressure container is generated, and the path length of the gas phase refrigerant is longer than was previously possible. When the direction of the opening of the delivery port faces upward and the angle α is adjusted, it becomes possible to adjust the distance X illustrated in Fig. 7 within a vertical plane, and it becomes possible to make the distance X larger while making the distance Y smaller. When 45° ≤ α is satisfied, the direction of the opening of the delivery port comes closer to a ceiling surface of the cylindrical pressure container or faces the ceiling surface, and the distance X can be made still larger. That is, it becomes possible to enhance an effect of impingement separation and an effect of centrifugal separation for the refrigerating machine oil at the same time.
Embodiments of the present disclosure will now be described with reference to the drawings.
Fig. 1 is a refrigerant circuit diagram illustrating an overall configuration of an outdoor unit 100 of an air conditioner according to an embodiment of the present disclosure. The outdoor unit 100 illustrated in Fig. 1 is an example of an air conditioner to which an oil separator 10 according to the present invention is applicable, and a range of application of the oil separator 10 is not limited to such an air conditioner.
The outdoor unit 100 includes a variable capacity compressor (DC inverter compressor) 30, the oil separator 10, an outdoor heat exchanger 31, an expansion valve 32, a four-way valve 33, a receiver tank 34, and an accumulator 35.
A suction pipe 41 extending through the accumulator 35 is connected to a suction opening of the compressor 30. A discharge pipe 42A is connected to a discharge opening of the compressor 30. The discharge pipe 42A is connected to the oil separator 10, and a discharge pipe 42B extending through the oil separator 10 is connected to the four-way valve 33.
The four-way valve 33 communicates one end of the outdoor heat exchanger 31 with the discharge pipe 42B or communicates one end of the outdoor heat exchanger 31 with a duct 43 linking to the suction pipe 41 of the compressor 30. Further, the four-way valve 33 communicates the discharge pipe 42B extending through the oil separator 10 with a gas pipe 46 or communicates the duct 43 linking through the accumulator 35 to the suction pipe 41 of the compressor 30 with the gas pipe 46.
The other end of the outdoor heat exchanger 31 is connected to the expansion valves 32 and the receiver tank 34, and further connected through a refrigerant pipe 44 to a liquid tube 45.
An oil return pipe 47 is connected to the oil separator 10; the oil return pipe 47 returns refrigerating machine oil stored in the oil separator 10 to the suction pipe 41 of the compressor 30.
The above refrigerating machine oil is lubricating oil for the compressor 30 contained in a gas phase refrigerant discharged from the compressor 30. The oil separator 10 separates the refrigerating machine oil from the refrigerant discharged from the compressor 30, returns the separated refrigerating machine oil to a suction side of the compressor 30, and supplies the gas phase refrigerant from which the refrigerating machine oil is removed to the four-way valve 33.
The outdoor unit 100 is connected through the liquid tube 45 and the gas pipe 46 to an indoor unit (not illustrated). The air conditioner in the embodiment is configured such that a refrigerant is circulated between the outdoor unit 100 and the indoor unit and the four-way valve 33 is switched, thereby enabling cooling operation or air-heating operation.
The oil separator 10 used for the air conditioner will next be described. Fig. 2 illustrates an inside of the oil separator 10 when the oil separator 10 is viewed from the upper direction. Fig. 3 illustrates the inside of the oil separator 10 when the oil separator 10 is viewed from the direction of arrow III in Fig. 2. Fig. 4 illustrates the inside of the oil separator 10 when the oil separator 10 is viewed from the direction of arrow IV in Fig. 2.
As illustrated in Figs. 2, 3, and 4, the oil separator 10 includes a pressure container (oil separator main body) 20, which is a cylindrical sealed container. The pressure container 20 is configured with a container upper section 21, a container lower section 22, and a container barrel section 29.
The container upper section 21 and the container barrel section 29 are joined, and the container lower section 22 and the container barrel section 29 are joined, by welding or the like. The openings are sealed with each other. An upper end plate 23 is formed on an upper surface of the container upper section 21 in an integrated manner. A lower end plate 24 is formed on a lower surface of the container lower section 22 in an integrated manner.
The upper end plate 23 is provided with a refrigerant inlet pipe 11 and a refrigerant outlet pipe 14. Figs. 2, 3, and 4 illustrate not only outer walls of the refrigerant inlet pipe 11 and the refrigerant outlet pipe 14, but also their inner walls.
The discharge pipe 42A extending from the discharge opening of the compressor 30 is connected to the refrigerant inlet pipe 11. The gas phase refrigerant that is discharged from the compressor 30 and contains the refrigerating machine oil is led into the pressure container 20 by the refrigerant inlet pipe 11.
The discharge pipe 42B linking to the four-way valve 33 is connected to the refrigerant outlet pipe 14. The gas phase refrigerant from which the refrigerating machine oil is separated is discharged to the outside of the pressure container 20 by the refrigerant outlet pipe 14.
The lower end plate 24 is provided with an oil outlet pipe 25. The oil outlet pipe 25 is connected to the oil return pipe 47. The refrigerating machine oil in the pressure container 20 is discharged to the outside of the pressure container 20 by the oil outlet pipe 25.
The container lower section 22 of the pressure container 20 is provided with two leg portions 26. The upper end part of each leg portion 26 is joined to a peripheral surface of the container lower section 22 by welding or the like. The lower end part of each leg portion 26 is bent so as to be parallel with a contact surface (bottom plate of the outdoor unit 100). That is, the leg portions 26 are formed in a substantially L shape.
The pressure container 20 is configured to be longitudinally mounted with a spacing from the contact surface while standing with the leg portions 26. Two leg portions 26 are assumed here, but three or more leg portions 26 may be used.
The refrigerant inlet pipe 11 and the refrigerant outlet pipe 14 are provided substantially parallel with a central axis AX of the cylindrical pressure container 20 and penetrate the upper end plate 23 substantially vertically. The refrigerant inlet pipe 11 is introduced through the upper end plate 23 at a position deviated from a center C of the pressure container 20. On the other hand, the refrigerant outlet pipe 14 is introduced through the upper end plate 23 at the position of the center C of the pressure container 20.
In the upper end plate 23, through- holes 27 and 28 are formed through which the refrigerant inlet pipe 11 and the refrigerant outlet pipe 14 are introduced, respectively. The refrigerant inlet pipe 11 and the refrigerant outlet pipe 14 are introduced through the through- holes 27 and 28, respectively, and the entire peripheries of the refrigerant inlet pipe 11 and the refrigerant outlet pipe 14 are sealed by brazing.
The refrigerant inlet pipe 11 has a curved portion 12. The refrigerant inlet pipe 11, which penetrates the upper end plate 23 and extends into the pressure container 20 substantially vertically, is curved in a U shape within the pressure container 20, so that the direction of the opening of the delivery port 13 that delivers the gas phase refrigerant faces upward. The direction of the opening may also be referred to as the direction in which the gas phase refrigerant flows out of the delivery port 13.
Specifically, the refrigerant inlet pipe 11 is formed such that an angle α between a straight line along the direction of the opening of the delivery port 13 and a plane H perpendicular to the central axis AX of the pressure container 20 falls within a range of 45° ≤ α < 90°.
For example, Fig. 3 illustrates a case in which the direction of the opening of the delivery port 13 is faced toward a curved portion of the upper end plate 23 of the pressure container 20. In this case, the gas phase refrigerant delivered from the delivery port 13 collides against the curved portion of the pressure container 20. Then, a flow of the gas phase refrigerant is separated to a flow F1 moving further upward and a flow F2 moving further downward in the pressure container 20.
When the angle α is greater than or equal to 45°, the flow F1 is dominant over the flow F2. For the flow F1, the path length for an outflow from the refrigerant outlet pipe 14 is longer than that for the flow F2, and therefore more refrigerating machine oil can be separated.
Further, when the angle α is greater than or equal to 45°, the vertical component of velocity of the gas phase refrigerant delivered from the delivery port 13 is greater than or equal to the horizontal component of velocity of the gas phase refrigerant. Therefore, when the gas phase refrigerant collides against a side face inner wall of the pressure container 20, the gas phase refrigerant is efficiently directed further upward in the pressure container 20. Moreover, loss of kinetic energy of the flow of the gas phase refrigerant is suppressed.
In addition, because the angle α is a value within the above range, when the curved portion 12 is formed in the refrigerant inlet pipe 11, the gas phase refrigerant collides against the inner wall at the outward side of the curved portion 12. This also enables separation of the refrigerating machine oil from the gas phase refrigerant.
Thus, in the oil separator 10, the refrigerant inlet pipe 11 is formed such that the angle α falls within a range of 45° ≤ α < 90°.
A reticulated member such as a mesh filter may be provided inside the refrigerant inlet pipe 11 at the upstream side of the curved portion 12. This enables the reticulated member to separate the refrigerating machine oil from the gas phase refrigerant to some extent, and the oil separation efficiency of the entire oil separator 10 can be further improved.
In addition, it is desirable that the refrigerant inlet pipe 11 is placed at a position where a distance x from the inner wall of the pressure container 20 to the center position of the delivery port 13 satisfies a relationship of D/2 ≤ x ≤ 1.6D. In this relationship, D is an inner diameter of the refrigerant inlet pipe 11.
Fig. 5 illustrates an influence of the position of the delivery port 13 of the refrigerant inlet pipe 11 on a separation rate of refrigerating machine oil. In the graph in Fig. 5, the vertical axis represents the refrigerating machine oil separation rate, and the horizontal axis represents a ratio of the distance x to an inner diameter L of the pressure container 20. Moreover, D in Fig. 5 is the inner diameter of the refrigerant inlet pipe 11. This result was obtained by Monte Carlo simulation.
Fig. 5 shows that as the ratio x/L becomes smaller, the refrigerating machine oil separation rate becomes larger. This is because when the gas phase refrigerant rotates along the inner wall and the refrigerating machine oil is separated by centrifugal force, the closer the delivery port 13 to the inner wall of the pressure container 20, the shorter the time for refrigerating machine oil to reach the inner wall and the more easily the refrigerating machine oil is captured on the inner wall.
The refrigerating machine oil separation rate indicates the maximum value 100% when the distance x is D/2 (the ratio x/L is 7.3). This is a case in which the refrigerant inlet pipe 11 is in contact with the inner wall of the pressure container 20. The separation rate required for the oil separator 10 according to the specifications is a value greater than or equal to 85%. This separation rate is achieved when the distance x is smaller than or equal to 1.6D (the ratio x/L is 23.0). Accordingly, a range of D/2 ≤ x ≤ 1.6D is set.
The refrigerating machine oil is separated from the gas phase refrigerant, mainly when the gas phase refrigerant passes through the curved portion 12 of the refrigerant inlet pipe 11, when the gas phase refrigerant flowing out of the refrigerant inlet pipe 11 collides against the upper end plate 23, and when the gas phase refrigerant rotates within the pressure container 20.
In the oil separator 10, when the gas phase refrigerant passes through the curved portion 12 of the refrigerant inlet pipe 11, about 20% of the refrigerating machine oil contained in the gas phase refrigerant is separated. It is assumed that when the gas phase refrigerant collides against the upper end plate 23 and then the gas phase refrigerant rotates within the pressure container 20, about 80% of the refrigerating machine oil that has not been removed in the curved portion 12 is separated.
In this case, the separation rate of the entire oil separator 10 is about 85%. The above lower limit value of 85% for the separation rate according to the specifications has been determined based on these factors.
It is desirable that the direction of the opening of the delivery port 13 of the refrigerant inlet pipe 11 is not parallel with a surface normal direction of the inner wall of the pressure container 20 in the direction of the opening. If the direction of the opening of the delivery port 13 is parallel with the surface normal direction of the inner wall of the pressure container 20 in the direction of the opening, the gas phase refrigerant delivered from the delivery port 13 collides against the inner wall from the vertical direction, causing larger loss of kinetic energy of the gas phase refrigerant.
However, if the direction of the opening of the delivery port 13 is not parallel with the surface normal direction of the inner wall of the pressure container 20 in the direction of the opening, the gas phase refrigerant delivered from the delivery port 13 flows while deviating in a direction other than the delivery port 13. As a result, a high-speed rotational flow can be generated without loss of kinetic energy.
On the other hand, the refrigerant outlet pipe 14 penetrates the center C of the upper end plate 23 and a tip 15 of the refrigerant outlet pipe 14 extends further downward than the delivery port 13 of the refrigerant inlet pipe 11. The direction of the opening of the tip 15 is a vertically downward direction. In this way, the refrigerant outlet pipe 14 is placed so as not to interfere with the refrigerant inlet pipe 11.
The operation of the oil separator 10 will next be described. The gas phase refrigerant discharged from the compressor 30 is led into the pressure container 20 of the oil separator 10 through the discharge pipe 42A and the refrigerant inlet pipe 11. As described above, the gas phase refrigerant contains refrigerating machine oil.
The curved portion 12 of the refrigerant inlet pipe 11 is curved such that a high-temperature gas phase refrigerant discharged from the compressor 30 is delivered along an inner peripheral surface of the pressure container 20. Therefore, the gas phase refrigerant delivered from the delivery port 13 of the refrigerant inlet pipe 11 becomes a collision flow colliding against the upper end plate 23, and then becomes a flow rotating hard along the inner peripheral surface of the pressure container 20.
The refrigerating machine oil contained in the gas phase refrigerant that has become the collision flow has a higher density than the gas phase refrigerant, and therefore is separated from the gas phase refrigerant by inertia force upon collision against the container wall. Still-unseparated refrigerating machine oil scatters in an outside radius direction of the pressure container 20 and is separated from the gas phase refrigerant by centrifugal force generated from rotation of the gas phase refrigerant.
As described above, the refrigerant inlet pipe 11 is formed such that the angle α falls within a range of 45° ≤ α < 90°. In this case, the collision flow of the gas phase refrigerant collides against a ceiling surface of the upper end plate 23, and a rotational flow is generated from the ceiling surface. Therefore, because the height of the pressure container 20 can be used to make the path length of the rotational flow longer, the refrigerating machine oil separation rate can be improved.
If the refrigerant inlet pipe 11 is machined such that the direction of the opening of the delivery port 13 of the refrigerant inlet pipe 11 is a horizontal direction, the delivery port 13 may face further downward than the horizontal direction to some extent due to variations in the machining accuracy. In this case, there is a possibility that a rotational flow of the gas phase refrigerant delivered from the delivery port 13 also faces downward, the path length of the rotational flow of the gas phase refrigerant is insufficient, and the refrigerating machine oil is not separated sufficiently.
In contrast, in the oil separator 10, the direction of the opening of the delivery port 13 of the refrigerant inlet pipe 11 faces further upward than the horizontal direction and the angle α is a value within a range of 45° ≤ α < 90°. Therefore, because it is possible to prevent the direction of the opening of the delivery port 13 from facing further downward than the horizontal direction due to variations in the machining accuracy, the path length of the rotational flow of the gas phase refrigerant is longer than was previously possible, and the refrigerating machine oil separation rate can be improved.
Moreover, in the oil separator 10, the delivery port 13 of the refrigerant inlet pipe 11 can be close to the inner wall of the pressure container 20. Therefore, centrifugal force generated from a rotational flow enables reduction in the time before particles of the refrigerating machine oil move to the inner wall of the pressure container 20 and are captured on the inner wall. Accordingly, the refrigerating machine oil separation rate can be further improved.
If the refrigerant inlet pipe 11 is placed in contact with the inner wall of the pressure container 20, it is desirable to weld the refrigerant inlet pipe 11 and the pressure container 20. Accordingly, occurrence of vibrations can be suppressed.
In addition, in the oil separator 10, it is possible to keep a sufficient distance between the opening face of the delivery port 13 of the refrigerant inlet pipe 11 and the ceiling surface of the upper end plate 23. Accordingly, it is possible to diffuse the gas phase refrigerant delivered from the delivery port 13 of the refrigerant inlet pipe 11 before the gas phase refrigerant reaches the ceiling surface of the upper end plate 23.
As a result, it is possible to widen a range in which the gas phase refrigerant collides against the ceiling surface of the upper end plate 23, allowing a significant improvement in an effect of capturing the particles of the refrigerating machine oil on the ceiling surface of the upper end plate 23.
Inside the pressure container 20, the refrigerating machine oil separated from the gas phase refrigerant by centrifugal force falls under its own weight and is stored in the container lower section 22 of the pressure container 20. Then, the refrigerating machine oil is led out of the oil outlet pipe 25 provided in the bottom part of the pressure container 20 to the outside of the pressure container 20 and returned to the suction opening of the compressor 30 via the oil return pipe 47.
On the other hand, the gas phase refrigerant from which the refrigerating machine oil is separated inside the pressure container 20 is stored in a space higher than the liquid level of the refrigerating machine oil stored in the container lower section 22 of the pressure container 20. Then, the gas phase refrigerant enters the refrigerant outlet pipe 14 and is supplied to the four-way valve 33 through the discharge pipe 42B.
The refrigerant outlet pipe 14 is placed at the center of the pressure container 20, and does not disturb a flow rotating along the inner peripheral surface of the pressure container 20. Because the tip 15 of the refrigerant outlet pipe 14 is placed at the center of the flow rotating along the inner peripheral surface of the pressure container 20, it is possible to prevent scattered refrigerating machine oil from being led out of the tip 15, and it is possible to direct, to the discharge pipe 42B, the gas phase refrigerant from which most of the refrigerating machine oil is removed.
Fig. 6 is a streamline diagram illustrating an example of a flow of the gas phase refrigerant. The streamline diagram was obtained as a result of numerical simulation.
As illustrated in Fig. 6, the gas phase refrigerant flowing out of the refrigerant inlet pipe 11 collides against the ceiling surface of the oil separator 10. Then, the gas phase refrigerant falls within the oil separator 10 while rotating, and rises again. In this process, the refrigerating machine oil is separated from the gas phase refrigerant, and the gas phase refrigerant from which the refrigerating machine oil is separated flows out of the oil separator 10 through the refrigerant outlet pipe 14.
In the above embodiments, the refrigerant inlet pipe 11 is introduced into the pressure container 20 through the upper end plate 23. The refrigerant inlet pipe 11 may be introduced into the pressure container 20 through the side wall or the lower part (lower end plate 24) of the pressure container 20, provided that the angle α between a straight line along the direction of the opening of the delivery port 13 and a plane perpendicular to the central axis of the pressure container 20 satisfies 45° ≤ α < 90° : such an oil separator is not within the scope of the present invention.
As has been described above, as an oil separator provided in the first embodiment of the present disclosure, the oil separator 10 separates refrigerating machine oil contained in a gas phase refrigerant. The oil separator 10 includes the cylindrical pressure container 20, the refrigerant inlet pipe 11 that leads the gas phase refrigerant containing the refrigerating machine oil into the pressure container 20, and the refrigerant outlet pipe 14 that discharges the gas phase refrigerant from which the refrigerating machine oil is separated. The angle α between a straight line along the direction of the opening of the delivery port 13 at a tip of the refrigerant inlet pipe 11 introduced into the pressure container 20 and a plane perpendicular to the central axis of the pressure container 20 satisfies 45° < α < 90°.
In this configuration, not within the scope of the present invention, the gas phase refrigerant flows out of the refrigerant inlet pipe 11 obliquely upward and collides against the pressure container 20, and a high rate of gas phase refrigerant reaches the ceiling of the pressure container 20. Then, the gas phase refrigerant flows downward from the ceiling of the pressure container 20 while rotating.
Thus, even if there are variations in the machining accuracy of the refrigerant inlet pipe 11, the gas phase refrigerant does not flow out of the refrigerant inlet pipe 11 directly downward, and an influence of the variations in the machining accuracy is reduced. It is possible to enhance an effect of impingement separation and an effect of centrifugal separation for the refrigerating machine oil at the same time, and it is also possible to make a path length of a rotational flow longer than was previously possible.
The second embodiment of the present disclosure provides an oil separator in which, in the first embodiment, when D is the inner diameter of the refrigerant inlet pipe 11, the distance x from the inner wall of the pressure container 20 to the center position of the delivery port 13 of the refrigerant inlet pipe 11 satisfies a relationship of D/2 ≤ x ≤ 1.6D. In this configuration, because it is possible to shorten the time for the refrigerating machine oil to reach the inner wall, the oil separation rate can be improved significantly.
The third embodiment of the present disclosure provides an oil separator in which, in the first or second embodiment, the direction of the opening of the delivery port 13 of the refrigerant inlet pipe 11 is not parallel with the surface normal direction of the inner wall of the pressure container 20 in the direction of the opening. In this configuration, because the gas phase refrigerant delivered from the delivery port 13 flows while deviating in a direction other than the delivery port 13, loss of kinetic energy can be suppressed, and as a result, a high-speed rotational flow can be generated.
The fourth embodiment of the present disclosure provides an oil separator in which, in any one of the first to third embodiments, the direction of the opening of the delivery port 13 is faced toward a curved portion of the upper end plate 23 of the pressure container 20. In this configuration, the gas phase refrigerant can be smoothly directed upward in the pressure container 20, and loss of kinetic energy of the gas phase refrigerant can be suppressed.
The fifth embodiment of the present disclosure provides an oil separator in which, in any one of the first to fourth embodiments, the refrigerant inlet pipe 11 has the curved portion 12, and a reticulated member is provided inside the refrigerant inlet pipe 11 at the upstream side of the curved portion 12. In this configuration, the reticulated member can be used to separate the refrigerating machine oil from the gas phase refrigerant to some extent, and the oil separation efficiency can be further improved.
The sixth embodiment of the present disclosure assumes that, in any one of the first to fifth embodiments, the refrigerant outlet pipe 14 is connected to the pressure container 20 on the central axis AX of the pressure container 20, and the refrigerant inlet pipe 11 is connected to the pressure container 20 at a position deviated from the central axis AX of the pressure container 20. In this configuration, it is possible to prevent a disturbance in a flow rotating along the inner peripheral surface of the pressure container 20, and it is possible to prevent scattered refrigerating machine oil from being led out of the refrigerant outlet pipe 14.
The above embodiments are merely examples of specific aspects to which the present disclosure is applied, and do not limit the present disclosure. That is, the present disclosure may be implemented in aspects other than the above embodiments.
For example, in the above embodiments, the description has been made of a case in which the oil separator 10 is used for an air conditioner that includes one inverter compressor 30, but this is not a limitation; the oil separator 10 may be used for an air conditioner that includes a plurality of inverter compressors and constant-speed compressors. In addition, the oil separator 10 may also be used for a gas heat pump air conditioner.
The oil separator according to the present disclosure is useful as an oil separator that separates refrigerating machine oil contained in a gas phase refrigerant.

Claims

An oil separator (10) that separates refrigerating machine oil contained in a gas phase refrigerant by inertia force and centrifugal force, comprising:
a cylindrical pressure container (20) comprising an upper end plate (23) having a curved portion;

a refrigerant inlet pipe (11) that leads the gas phase refrigerant containing the refrigerating machine oil into the cylindrical pressure container, the refrigerant inlet pipe having a delivery port (13), wherein the direction of the opening of the delivery port (13) is faced toward the curved portion of the upper end plate (23) of the cylindrical pressure container (20); and

a refrigerant outlet pipe (14) that discharges the gas phase refrigerant from which the refrigerating machine oil is separated,

wherein an angle α between a straight line along a direction of an opening of a delivery port (13) at a tip of the refrigerant inlet pipe (11) introduced into the cylindrical pressure container (20) and a plane perpendicular to a central axis of the cylindrical pressure container satisfies 45° ≤ α < 90°,

wherein the refrigerant inlet pipe (11) and the refrigerant outlet pipe (14) are provided substantially parallel with a central axis (AX) of the cylindrical pressure container (20) and penetrate the upper end plate (23) substantially vertically,

wherein the refrigerant inlet pipe (11) penetrates the upper end plate (23) at a position deviated from a center (C) of the upper end plate (23),

wherein the refrigerant inlet pipe (11) has a curved portion curved in a U shape within the pressure container (20), so that the direction of the opening of the delivery port (13) faces upward,

characterized in that

an oil outlet pipe (25) is provided in a lower end plate (24) of the pressure container (20), and

the refrigerant outlet pipe (14) penetrates the center (C) of the upper end plate (23), and

a tip (15) of the refrigerant outlet pipe (14) extends further downward than the delivery port (13) of the refrigerant inlet pipe (11) and the direction of the opening of the tip (15) is a vertically downward direction.
The oil separator according to claim 1,
wherein when D is an inner diameter of the refrigerant inlet pipe (11), a distance x from an inner wall of the cylindrical pressure container (20) to a center position of the delivery port (139) satisfies a relationship of D/2 ≤ x ≤ 1.6D.
The oil separator according to claim 1,
wherein the direction of the opening of the delivery port is not parallel with a surface normal direction of the inner wall of the cylindrical pressure container (20) in the direction of the opening (13).
The oil separator according to claim 1,
wherein the refrigerant inlet pipe (11) has a curved portion (12), and a reticulated member is provided inside the refrigerant inlet pipe at an upstream side of the curved portion (12).
The oil separator according to claim 1,
wherein the refrigerant outlet pipe (14) is connected to the cylindrical pressure container (20) on the central axis of the cylindrical pressure container, and the refrigerant inlet pipe (11) is connected to the cylindrical pressure container at a position deviated from the central axis of the cylindrical pressure container.