JP2013015069A - Oil separator and compressor having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator enhancing a separating efficiency.SOLUTION: In the oil separator for a compressor, an oil flowing out space is arranged in an outer peripheral surface of an inner peripheral separating cylinder, and a plurality of communication holes communicating to the oil flowing out space are arranged in the inner peripheral separating cylinder. Coolant into which oil is mixed flows into from a flowing in opening arranged in a tangential direction of the cylindrical space part inner wall and the coolant is turned along the cylindrical space part inner wall and the inner peripheral separating cylinder, the oil sticking to the inner peripheral separating cylinder in flows out from the communication holes to the oil flowing out space by a centrifugal force.

Description

  The present invention relates to an oil separator for a compressor, and is effective for use in a heat pump system or the like equipped with a compressor for CO2 refrigerant.

  The compressor used in the refrigeration cycle lubricates the compressor by mixing oil in the refrigerant gas, but part of this lubricating oil is discharged to the refrigeration cycle together with the refrigerant gas. The more lubricating oil discharged into the refrigeration cycle, the lower the system efficiency (also referred to as COP or coefficient of performance) of the refrigeration cycle. In order to suppress oil discharge into the refrigeration cycle, it is known to provide a centrifugal oil separator that separates lubricating oil from refrigerant gas on the discharge side of the compressor, as seen in Patent Document 1. ing.

  In recent years, CO2 (carbon dioxide) has been used as a refrigerant in consideration of environmental problems. However, since the CO2 refrigerant has a smaller density difference from the oil than the conventional 134a refrigerant, the conventional oil separator is not sufficiently centrifuged and the oil separation efficiency is lowered. For this reason, the oil rate in a refrigerating cycle increases, the heat exchange performance in a gas cooler or an evaporator is impaired, and there existed a problem that COP fell. As a characteristic characteristic of the CO2 refrigerant cycle, the heat exchanger efficiency is greatly increased in an environment where the oil rate is low as compared with the conventional refrigerant, and a reduction in the oil rate by further improving the separation efficiency has been demanded.

  The centrifugal oil separator 101 of Patent Document 1 is attached to the following refrigerant compressor. FIG. 1 is a cross-sectional view of a refrigerant compressor provided with the oil separator of Patent Document 1. This refrigerant compressor is a scroll type compressor, and houses an electric motor part 55 and a compression mechanism part 57 in a sealed container 53, compresses refrigerant from an external refrigerant circuit, and is integrated with one end thereof. Oil is separated from the refrigerant compressed by the attached oil separator 101, and the refrigerant is sent to an external refrigerant circuit, while the separated oil is returned to a movable part such as a compression mechanism.

  The airtight container 53 of the refrigerant compressor is formed of a cylindrical first housing 59, a second housing 61, and a third housing 63. The sealed container 53 forms a so-called internal low-pressure container whose pressure is lower than the refrigerant discharge pressure. The compression mechanism 57 includes a movable scroll 69 that revolves by a crank mechanism 67 supported by a main bearing 65, and a fixed scroll 71 that is disposed to face the movable scroll 69. The crank mechanism 67 and the movable scroll 69 are Rotated by the shaft 75 of the electric motor unit 55 supported horizontally by the main bearing 65 and the sub bearing 73.

  The fixed scroll 71 and the movable scroll 69 each have a spiral groove, and a plurality of working chambers 77 formed by the engagement of the grooves reduce the volume, thereby reducing the outermost circumference of the spiral groove of the fixed scroll 71. The refrigerant supplied to the suction chamber communicating with the side is compressed. A discharge chamber 81 communicates with the working chamber 77 of the compression mechanism 57 via a discharge port 79, and one end of the suction pipe 25 of the oil separator 101 is connected to the discharge chamber 81. The other end of the suction pipe 25 is connected to a refrigerant inlet 23 provided in the separation part 13 of the oil separator 101. The separation unit 13 has a bottomed cylindrical separation cylinder 17. A refrigerant discharge part 19 is provided in the upper opening of the separation cylinder 17. The refrigerant discharge portion 19 includes a large diameter portion (upper opening portion) 19a that fits into the upper opening of the separation cylinder 17, and a separation pipe 19b that is a small diameter cylinder formed below the large diameter portion 19a. ing.

  An oil return passage 83 is formed below the fixed scroll 71, and an oil feed pipe 33 is connected to one end of the oil return passage 83. The other end of the oil return passage 83 communicates with the sliding interface between the fixed scroll 71 and the movable scroll 69, and a plurality of oil passages are formed from there to other movable portions that need lubrication. . One end of the oil feeding pipe 33 is connected to an oil feeding port 87 provided at the bottom of the oil storage part 85. The oil storage container 89 of the oil storage unit 85 is formed of a third housing 63 and a fourth housing 91.

  The refrigerant supplied through the inflow pipe 25 from the discharge chamber 81 adjacent to the compression mechanism unit 57 is swirled in the annular space 21 of the separation unit 13 to separate the oil 1, and the refrigerant is transferred from the refrigerant discharge unit 19 to the external refrigerant circuit. On the other hand, the oil 1 is caused to flow down to the oil storage chamber 93 from the communication hole 17 b provided in the bottom wall portion 17 a of the separation cylinder 17. The oil stored in the oil storage chamber 93 is returned from the oil supply port 87 to the oil return passage 83 through the oil supply pipe 33 and supplied to a sliding portion such as a sliding surface of the fixed and rotary scroll.

The conventional centrifugal cylinder system as in Patent Document 1 has the following problems.
2A is a front cross-sectional view of a conventional centrifuge cylinder system, FIG. 2B is a cross-sectional view taken along line AA, and FIG. It is explanatory drawing explaining the wall surface adhesion of 1. FIG. As shown in FIGS. 2A to 2C, the oil 1 and the refrigerant flowing in from the inlet 23 that is offset with respect to the separation cylinder 17 are swirled and the dense oil 1 is separated from the inner wall 17 of the separation cylinder 17 by centrifugal force. While falling while rotating while adhering to ', the refrigerant having a low density turns to the inner diameter of the separation pipe and the oil and the refrigerant are separated.

  FIG. 3 is an explanatory diagram analyzing the flow state of the conventional centrifugal cylinder system of FIG. The size of the triangle represents the flow velocity, and the arrow direction represents the direction of flow. As can be seen in this simulation, a strong turn flow is generated in the region (hereinafter referred to as separation pipe lower end region K) in the separation cylinder inner wall 17 'in the vicinity of the lower end portion of the separation pipe 19a. The oil present on the wall surface of K is entrained in the turn flow (the oil adhering to the separation cylinder inner wall 17 'is generated). For this reason, when the separation efficiency exceeds a certain level, no matter how much the centrifugal separation is performed, the oil 1 existing on the wall surface is caught in the turn flow, and the separation efficiency is not improved any more. That is, as seen in FIG. 2 (c), the separation efficiency depends on the amount of oil present on the wall surface of the separation pipe lower end region K.

JP 2009-92060 A

  In view of the above problems, the present invention provides an oil separator in which the separation cylinder has a double structure, conceived that reducing the amount of oil between the separation pipe and the separation cylinder leads to improvement in separation efficiency.

  In order to solve the above-mentioned problems, the invention of claim 1 includes an upper opening (19a) for discharging refrigerant to the outside, a separation cylinder (17) having a cylindrical space (20), and the upper opening. A separation pipe (19b) connected to (19a) and disposed in the cylindrical space portion (20), and an inner peripheral separation tube (19c) formed continuously from the inner wall (17 ′) of the cylindrical space portion And an oil outflow space (22) is provided on the outer peripheral surface of the inner peripheral separation cylinder (19c), and the inner peripheral separation cylinder (19c) A plurality of communication holes (7) communicating with the oil outflow space (22) are provided, and oil is mixed from an inflow port (23) installed in a tangential direction of the inner wall (17 ') of the cylindrical space portion. The inside of the cylindrical space (1 ') And the oil that is swung along the inner peripheral separation cylinder (19c) and attached to the inner peripheral separation cylinder (19c) by centrifugal force flows out from the communication hole (7) into the oil outflow space (22). And an oil separator for a compressor in which the refrigerant from which oil has been separated is discharged from the upper opening (19a) through the separation pipe (19b).

  Thereby, the oil adhering to the inner wall of the inner peripheral separation cylinder can be discharged to the oil outflow space by the communication hole provided in the inner peripheral separation cylinder. And the oil adhering to the inner wall of the inner peripheral separation cylinder can be reduced in the amount of oil spilled around the turn flow and discharged to the outside, and the separation efficiency can be remarkably improved.

  According to a second aspect of the present invention, in the first aspect of the present invention, at least the communication hole is located closer to the inlet (23) than the inner peripheral separation cylinder (19c) corresponding to the lower end of the separation pipe (19b). A plurality of (7) are provided. Thereby, the oil adhering to the inner wall of the inner peripheral separation cylinder can be efficiently discharged to the oil outflow space.

  The invention of claim 3 is characterized in that, in the invention of claim 2, a total area of the plurality of communication holes (7) provided is smaller than a passage sectional area of the inflow port (23). Thereby, it is possible to prevent the refrigerant gas from being discharged into the oil outflow space and preventing the oil from adhering to the inner wall of the inner peripheral separation cylinder from flowing out.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the total area of the plurality of communicating holes (7) is an annular space between the separation pipe (19b) and the inner peripheral separation cylinder (19c). With respect to the passage cross-sectional area (flow direction cross section) of (21), the area ratio is larger than 0 and smaller than 0.35. Thereby, only oil can be made to flow in without much refrigerant gas flowing into oil outflow space.

  A fifth aspect of the present invention is a compressor comprising the compressor oil separator according to any one of the first to fourth aspects. The same effect as in claim 1 is produced.

According to a sixth aspect of the present invention, in the compressor according to the fifth aspect, a CO ₂ refrigerant is used. In a compressor using a CO2 refrigerant, centrifugal separation can be sufficiently performed with an oil separator, and oil separation efficiency can be improved.

  In addition, the code | symbol attached | subjected above is an example which shows a corresponding relationship with the specific embodiment as described in embodiment mentioned later.

It is sectional drawing of the refrigerant compressor provided with the oil separator of patent document 1. (A) is front sectional drawing of the conventional centrifuge cylinder system, (b) is a cross-sectional view regarding the AA line, (c) is a wall surface of oil in the conventional centrifuge cylinder system. It is explanatory drawing explaining adhesion. It is explanatory drawing which analyzed the state of the flow of the conventional centrifuge cylinder system of Fig.2 (a). (A) is sectional drawing which shows the oil separator of one Embodiment of this invention, (b) is a cross-sectional view regarding the BB line of (a), (c) is an inner peripheral separation cylinder. It is a perspective view of 19c. It is a graph which shows the relationship between the area ratio of the communicating hole with respect to the annular space 21 of the communicating hole 7, and separation efficiency.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. About each embodiment, the same code | symbol is attached | subjected to the part of the same structure, and the description is abbreviate | omitted. Parts having the same configuration in each embodiment with respect to the prior art are similarly denoted by the same reference numerals and description thereof is omitted.

  An oil separator according to an embodiment of the present invention is also attached to a refrigerant compressor similar to that of Patent Document 1. The oil separator according to an embodiment of the present invention is not limited to the refrigerant compressor disclosed in Patent Document 1, and is not limited to a scroll compressor, but may be other types of compressors (rolling piston type, slide vane type). The reciprocating type oil separator may be widely applied. The oil separator according to an embodiment of the present invention is not limited to a horizontal type, and may be a compressor having a vertical type. The oil storage part 85 is not limited to the inside of the sealed container 53 but may be applied to a type installed outside. The oil separator according to one embodiment of the present invention is significantly improved in separation efficiency in an oil separator applied to a compressor using a CO2 refrigerant. However, even when other refrigerants are used, the oil separator is separated. Efficiency is improved.

Hereinafter, the oil separator of one embodiment of the present invention will be described as being attached to a refrigerant compressor similar to that of Patent Document 1.
4A is a cross-sectional view showing an oil separator according to an embodiment of the present invention, FIG. 4B is a cross-sectional view taken along line BB in FIG. 4A, and FIG. It is a perspective view of the separation cylinder 19c.

The separation cylinder 17 includes an upper opening 19 a that discharges the refrigerant to the outside and a cylindrical space 20. The upper end of the separation pipe 19b is fitted and fixed to the partition portion 17 '' that partitions the upper opening 19a and the cylindrical space portion 20 of the separation cylinder 17, and the lower end side of the separation pipe 19b is illustrated in FIG. As shown to 4 (a), it installs in the cylindrical space part 20 so that it may protrude. The central axis of the cylindrical space portion 20 and the central axis of the separation pipe 19b coincide. In addition, you may comprise the upper opening part 19a and the isolation | separation pipe 19b with a reduced diameter pipe | tube like FIG.
An inner peripheral separation cylinder 19c is installed continuously to the cylindrical space inner wall 17 ', and an oil outflow space 22 is provided on the outer peripheral surface of the inner peripheral separation cylinder 19c. An annular space 21 is formed between the outer peripheral surface of the separation pipe 19b and the cylindrical space portion inner wall 17 ′ and the inner peripheral separation cylinder 19c.

  The high-pressure refrigerant compressed from the discharge port 79 of the compression mechanism 57 flows into the cylindrical space 20 of the separation cylinder 17 from the inlet 23 via the suction pipe 25. The oil 1 and the refrigerant flowing from the inlet 23 that is offset with respect to the separation cylinder 17 are swirled in the annular space 21 to become a swirling flow, and the dense oil 1 is attached to the inner wall 17 ′ of the cylindrical space portion by centrifugal force. While turning, it falls downward, and the low-density refrigerant turns to the inner diameter of the separation pipe 19b to separate the oil and the refrigerant. The refrigerant from which the oil 1 has been separated passes through the separation pipe 19b and is sent out from the upper opening 19a to an external refrigerant circuit.

The separation cylinder 17 is structurally different from the conventional centrifugal separation cylinder system in the following points.
An inner peripheral separation cylinder 19c is provided continuously to the inner wall 17 ′ of the cylindrical space portion, and a cylindrical oil outflow space 22 is provided behind the inner peripheral separation cylinder 19c. The inner peripheral separation cylinder 19c is provided with a plurality of communication holes 7 in the lower end region K of the separation pipe. As shown in FIG. 4 (a), as an example, two rows of holes at 90 ° intervals in four directions are arranged above the lower end of the separation pipe 19b, and one row is arranged slightly below the lower end of the separation pipe.

As for the size and number of the communication holes 7, since not only oil but also refrigerant gas flows in if the number is large and the number is large, at least the total area of the communication holes 7 above the lower end of the separation pipe 19b is the inflow port. The passage area S or less is good. Thereby, it is possible to prevent the refrigerant gas from flowing into the oil outflow space 22 too much. Although the communication hole 7 is a hole, it may have a slit-like shape, and the holes and slits may be arranged in a staggered pattern. At least a plurality of communication holes 7 are provided on the inflow port 23 side from the portion of the inner peripheral separation cylinder 19c corresponding to the lower end portion of the separation pipe 19b.
Furthermore, from an experimental investigation of the relationship between the total area of the communication holes 7 and the separation efficiency, the total area of the communication holes 7 is larger than 0 in area ratio with respect to the axially downward channel cross-sectional area of the annular space 21, When it is smaller than 0.35, the separation efficiency is improved, and the effect is greatest when the area ratio is about 0.2 (see FIG. 5). Within this range, an effect is obtained because only the oil can flow in without causing a large amount of refrigerant gas to flow into the oil outflow space 22.

Separation by the oil separator according to one embodiment of the present invention is performed as follows.
From the inflow port 23, inflowing refrigerant and oil swirl in the annular space 21 between the separation pipe 19b and the inner circumferential separation cylinder 19c, and the oil adheres to the inner wall of the inner circumferential separation cylinder 19c by centrifugal force. Then, oil flows out from the communication hole 7 provided in the inner peripheral separation cylinder 19c to the outer oil outflow space 22 by the action of centrifugal force. At the time when the swirling flow reaches the lower end region K of the separation pipe from the inlet 23, the amount of oil adhering to the wall surface of the inner peripheral separation cylinder 19c is reduced as compared with the case without the communication hole 7 due to the outflow action by the communication hole 7. To do. The outflow action by the communication hole 7 is promoted by the action of the centrifugal flow centrifugal force.
Therefore, the oil attached to the inner wall of the inner peripheral separation cylinder 19c is wound in the turn flow, and the amount of oil flowing out from the upper opening 19a through the separation pipe 19b can be reduced. It can be significantly improved.

Thereafter, the oil falls from the oil outflow space 22 toward the bottom portion 17a of the cylindrical space portion 20, stays in the bottom portion 17a, and then flows down from the outlet port 17b to the oil storage portion 93.
A centrifugal oil separator that omits the separation pipe and is simplified is also known, but even in that case, the concept of the present invention is naturally applicable, and at an appropriate position (at least upstream of the position where the turn flow is generated). ) If the communication hole is installed, the same effect can be obtained.

7 communication hole 17 'cylindrical wall inner wall 19a upper opening 19b separation pipe 19c inner circumference separation cylinder 20 cylindrical space 21 annular space 22 oil outflow space 23 inlet

Claims (6)

An upper opening (19a) that discharges the refrigerant to the outside, a separation cylinder (17) having a cylindrical space (20), and the cylindrical space (20) connected to the upper opening (19a). An oil separator for a compressor comprising a separation pipe (19b) disposed in the inner space (17 ') and an inner peripheral separation cylinder (19c) formed continuously on the inner wall (17') of the cylindrical space,
An oil outflow space (22) is provided on an outer peripheral surface of the inner peripheral separation cylinder (19c), and a plurality of communication holes communicating with the oil outflow space (22) are provided in the inner peripheral separation cylinder (19c). (7) is provided,
From the inlet (23) installed in the tangential direction of the cylindrical space inner wall (17 '), an oil-mixed refrigerant is introduced to separate the cylindrical space inner wall (17') and the inner circumference. The oil swirled along the cylinder (19c) and attached to the inner circumferential separation cylinder (19c) by centrifugal force is allowed to flow out from the communication hole (7) to the oil outflow space (22) and the oil is separated. An oil separator for a compressor in which the refrigerant passes through the separation pipe (19b) and is discharged to the outside from the upper opening (19a).   A plurality of the communication holes (7) are provided on the inflow port (23) side at least from the portion of the inner peripheral separation cylinder (19c) corresponding to the lower end of the separation pipe (19b). The oil separator for compressors according to claim 1.   The oil separator for a compressor according to claim 2, wherein a total area of the plurality of communication holes (7) provided is smaller than a passage cross-sectional area of the inlet (23).   The total area of the plurality of communication holes (7) provided is an area ratio with respect to the cross-sectional area of the annular space (21) between the separation pipe (19b) and the inner peripheral separation cylinder (19c). 4. The oil separator for a compressor according to claim 3, wherein the oil separator is larger than 0 and smaller than 0.35.   A compressor comprising the oil separator for a compressor according to claim 1.   6. The compressor according to claim 5, wherein a CO2 refrigerant is used.