JP2020085424A - Oil separator - Google Patents

Abstract

To prevent insufficient discharge of separated oil from an oil return pipe.SOLUTION: There is provided an oil separator separating, from a refrigerant gas discharged from a compressor, oil included in the refrigerant gas. The oil separator comprises: a housing comprising a cylindrical housing boy with vertically extending center axis, an upper end plate connected to an upper part of the housing body, and a reduced portion connected to a lower part of the housing body and formed in such a manner that a cross section orthogonal to the center axis becomes smaller as approaching the lower side; an oil return pipe connected to a lower part of the reduced portion; and a discharge pipe extending vertically through the upper end plate. The oil separator satisfies relationship D1/L≥0.45 where D1 denotes the vertical distance between the lower end of the discharge pipe and the lower end of the housing body and L denotes the vertical distance between the upper end of the upper end plate and the lower end of the reduced portion.SELECTED DRAWING: Figure 2

Description

The present invention relates to an oil separator.

Generally, a refrigeration cycle device having a compressor, a condenser, an expansion valve, and an evaporator and having a refrigerant circuit for circulating a refrigerant is known. The compressor of this refrigeration cycle apparatus accommodates a compression element and oil in a case, and supplies this oil to a bearing portion and a sliding portion of the compression element for lubrication. Since part of the oil is discharged into the refrigerant circuit together with the refrigerant gas, an oil separator that separates the oil from the refrigerant gas is provided on the discharge side of the compressor.

As this type of oil separator, a so-called centrifugal separation type oil separator has been conventionally known (see, for example, Patent Document 1). This oil separator has a refrigerant gas inflow pipe connected tangentially to the inner wall surface of the cylindrical housing, and the refrigerant gas containing oil swirls in the housing, so that the oil adheres to the inner wall surface of the housing. Separated. The separated oil is returned into the case of the compressor through an oil return pipe connected to the lower part of the housing, and the refrigerant gas from which the oil is separated flows through the refrigerant circuit and is returned to the suction side of the compressor again.

JP, 11-173706, A

However, in the invention described in Patent Document 1, the separation efficiency may decrease as the circulation amount of the refrigerant gas increases. Specifically, as the circulation amount of the refrigerant gas increases, the centrifugal force during the swirling motion becomes stronger, and the separated oil is pressed against the inner wall surface of the housing. When the oil is pressed against the inner wall surface of the housing, the oil is not sufficiently discharged to the oil return pipe connected to the bottom of the housing.

It is an object of the present invention to provide an oil separator that can prevent insufficient discharge of oil separated by adhering to the inner wall surface of a housing from an oil return pipe.

According to the first aspect of the present invention, the oil separator is an oil separator that separates the oil contained in the refrigerant gas discharged from the compressor from the refrigerant gas, and has a cylindrical shape whose central axis extends in the vertical direction. A housing body, an upper end plate connected to the upper side of the housing body, and a reduction section connected to the lower side of the housing body and having a cross section orthogonal to the central axis becoming smaller toward the lower side. A housing having a housing, an oil return pipe connected to a lower portion of the reduced portion, and a discharge pipe extending vertically through the upper end plate, and a lower end of the discharge pipe and a lower end of the housing body. Let D1 be the distance in the vertical direction and L be the distance in the vertical direction between the upper end of the upper end plate and the lower end of the reduced portion, then D1/L≧0.45.

According to this structure, since the reduced portion is provided in the lower portion of the housing, it is possible to prevent insufficient discharge of the oil separated by being attached to the inner wall surface of the housing from the oil return pipe. can do.
Further, by defining D1/L≧0.45, it is possible to secure a capacity that functions as an oil separator, and to suppress the oil attached to the inner wall surface of the housing from being discharged through the discharge pipe. it can.

In the oil separator, the reducing portion has a conical shape, and an angle formed by inner surfaces of the reducing portion in a cross section of the reducing portion including a central axis of the reducing portion may be 60° or less. ..

According to such a configuration, the steep slope formed by the inner surface of the reduced portion allows the oil on the inner surface of the reduced portion to easily flow.

In the oil separator, when the outer diameter of the housing is OD, the central axis of the oil return pipe may be arranged outside a circle having a diameter OD/2 centered on the central axis of the housing when viewed from above. ..

According to such a configuration, the oil return pipe is connected so as to be close to the inner wall surface of the housing, so that the oil is easily introduced into the oil return pipe. This makes it possible to prevent insufficient discharge of oil from the oil return pipe.

Further, according to the second aspect of the present invention, the oil separator is an oil separator that separates oil contained in the refrigerant gas discharged from the compressor from the refrigerant gas, and has a central axis extending in the vertical direction. -Shaped housing body, an upper end plate connected to the upper part of the housing body, and an upper end plate connected to the lower part of the housing body, a housing connected to the bottom of the housing, an oil return pipe, A discharge pipe extending vertically through the upper end plate, and the outer diameter of the housing is OD, the central axis of the oil return pipe is centered on the central axis of the housing when viewed from above. It is located outside the circle of diameter OD/2.

According to such a configuration, the oil return pipe is connected so as to be close to the inner wall surface of the housing, so that the oil is easily introduced into the oil return pipe. This makes it possible to prevent insufficient discharge of oil from the oil return pipe.

The oil separator may include two or more of the oil return pipes, and the oil return pipes may be arranged such that the distance between them is the greatest.

According to such a configuration, since a plurality of oil return pipes are provided, more oil can be introduced into the oil return pipe.

According to the present invention, it is possible to prevent insufficient discharge of the oil separated by adhering to the inner wall surface of the housing from the oil return pipe.

It is a block diagram which shows the refrigerating-cycle apparatus of 1st embodiment of this invention. It is sectional drawing of the oil separator of 1st embodiment of this invention. It is sectional drawing of the oil separator of 2nd embodiment of this invention. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is sectional drawing of the oil separator of 3rd embodiment of this invention. FIG. 6 is a VI-VI sectional view of FIG. 5. It is sectional drawing of the conventional oil separator. It is a graph which shows the experimental result which compared about the oil discharge amount from an oil separator.

[First embodiment]
Hereinafter, the oil separator of the first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram showing a refrigeration cycle apparatus 50 having an oil separator 1 according to the first embodiment of the present invention.
As shown in FIG. 1, the refrigeration cycle apparatus 50 of the present embodiment includes an outdoor unit 52, an indoor unit 53 connected to the outdoor unit 52, and a refrigerant pipe (gas pipe 54 and liquid pipe 55). A refrigerant circuit 51 is provided. If the outdoor units 52 are sequentially connected in parallel, the number of indoor units 53 may be increased.

The outdoor unit 52 includes a compressor 56 that compresses a refrigerant gas introduced through a gas pipe 54, and an oil (refrigerator oil) contained in the refrigerant gas that is discharged from the compressor 56 through a compressor discharge pipe 61. ) Are separated from each other, and a condenser 57 (outdoor heat exchanger) for exchanging heat between the outdoor air and the refrigerant to condense is provided as main components.

The indoor unit 53 includes an evaporator 58 (indoor heat exchanger) that heat-exchanges indoor air and a refrigerant to evaporate, and an expansion valve 59 as main components. The expansion valve 59 is a valve that decompresses the high-temperature, high-pressure liquid refrigerant introduced from the condenser 57 via the liquid pipe 55 into a state in which it is easily evaporated.

The compressor 56 is a machine that compresses the refrigerant gas introduced at a low pressure and discharges it to the oil separator 1. The compressor 56 includes a compression element 64 inside a case 63. The compression element 64 compresses the low pressure refrigerant gas sucked through the gas pipe 54 and discharges the high temperature and high pressure refrigerant gas from the compressor discharge pipe 61.
The compression element 64 is driven by an electric motor section (not shown). The rotation speed of the compression element 64 is adjusted by changing the operating frequency of the electric motor section. In the case 63, oil for lubricating each part (the bearing part and the sliding part) of the compression element 64 is stored.

The oil separator 1 is provided on the downstream side of the compressor 56. The oil separator 1 is a device that separates oil from the refrigerant gas discharged from the compressor discharge pipe 61 by centrifugal force or the like.
As shown in FIG. 2, the oil separator 1 has a housing 2 which is a closed container, and can store the oil separated from the refrigerant gas.

The housing 2 includes a cylindrical housing body 3, an upper end plate 4 connected to the upper end of the housing body 3, and a reduction portion 5 connected to the lower end of the housing body 3. The housing body 3, the upper end plate 4, and the reduction section 5 are integrally formed. The upper end plate 4 is curved outward. A refrigerant gas inflow pipe 7 connected to the compressor discharge pipe 61 is connected to an upper portion of the housing body 3. An oil separator discharge pipe 6 is connected to the upper end plate 4.

The refrigerant gas inflow pipe 7 is a pipe for introducing the refrigerant gas discharged from the compressor discharge pipe 61 of the compressor 56 into the housing 2. The refrigerant gas inflow pipe 7 extends horizontally in the connection portion with the housing 2.
The refrigerant gas inflow pipe 7 is connected in the tangential direction of the inner wall surface 2a of the housing body 3. In other words, the refrigerant gas inflow pipe 7 is arranged so that the refrigerant gas introduced into the housing 2 is along the inner wall surface 2a of the housing 2. As a result, the refrigerant gas containing the oil mist introduced into the housing 2 from the refrigerant gas inflow pipe 7 swirls in the housing 2. The refrigerant gas swirls in the housing 2, whereby oil adheres to the inner wall surface 2 a of the housing 2 and is separated. The separated oil flows downward due to its own weight.

The oil separator discharge pipe 6 is a pipe for discharging the refrigerant gas, in which the oil is separated in the housing 2, to the outside of the housing 2. The oil separator discharge pipe 6 extends in the vertical direction and penetrates the upper end plate 4. The center axis of the oil separator discharge pipe 6 is preferably aligned with the center axis A1 of the housing body 3. The position of the lower end 6 a of the oil separator discharge pipe 6 is lower than that of the refrigerant gas inflow pipe 7.

An oil return pipe 8 for returning the oil separated in the housing 2 to the compressor 56 (see FIG. 1) is connected to the reduction unit 5. The oil return pipe 8 extends downward and is connected to the compressor 56 via an electromagnetic valve 66 and a capillary pipe 67 (throttle) as shown in FIG.
Since the inside of the housing 2 has a pressure equivalent to the discharge pressure of the compressor 56, the oil separated in the housing 2 is separated into the discharge pressure and the suction pressure of the compressor 56 by opening the solenoid valve 66. Due to the pressure difference of, the pressure is returned into the case 63 of the compressor 56. The high-pressure oil in the housing 2 is depressurized when passing through the capillary tube 67.

The reducing portion 5 is formed so as to gradually reduce its diameter as it goes downward. In other words, the reduced portion 5 has a tapered shape in which the diameter around the central axis gradually decreases as it goes downward.
The contracting portion 5 has a conical shape in which the top portion 5a faces downward, and the lower end 3a of the housing body 3 is connected to the circular end portion 5b of the conical surface. An oil return pipe 8 is connected to the top portion 5a of the reduction unit 5. The reduction section 5 does not need to have a perfect conical shape. The reducing portion 5 does not need to have a linear cross-sectional shape including the central axis, and may have, for example, an outwardly convex curved shape. It is sufficient that the reduction section 5 has a cross section that is gradually orthogonal to the central axis A1 as it goes downward.

In the cross-sectional shape including the central axis A1 of the reduced portion 5 as shown in FIG. 2, the angle θ formed by the inner surfaces of the reduced portion 5 is 60°. The angle θ is preferably 60° or less.
The total length L of the housing 2, that is, the vertical distance L between the upper end of the upper end plate 4 and the lower end 5a of the reduction unit 5 can be 240 mm to 400 mm depending on the specifications of the refrigeration cycle apparatus 50.
The diameter OD of the housing 2 can be 52 mm to 67 mm depending on the specifications of the refrigeration cycle device 50.

The vertical distance D1 between the lower end 6a of the oil separator discharge pipe 6 and the lower end 3a of the housing body 3 is preferably 190 mm or more. In other words, the distance D1 from the lower end 3a of the housing body 3 to the inlet of the oil separator discharge pipe 6 is preferably 190 mm or more.

However, this is not the case when the total length L of the housing 2 is short. It is preferable that the distance D1 and the total length L of the housing 2 satisfy the following mathematical expressions.
D1/L ≧ 0.45

The vertical distance D2 between the central axis A2 of the refrigerant gas inflow pipe 7 and the lower end 6a of the oil separator discharge pipe 6 is preferably 29 mm or more.

According to the above-described embodiment, the refrigerant gas containing the oil swirls in the housing 2, whereby the oil adheres to the inner wall surface 2 a of the housing 2 and is separated. Next, when the oil attached to the inner wall surface 2a reaches the reducing portion 5, the oil slides down the slope of the reducing portion 5 due to the action of gravity and moves downward, and is collected in the oil return pipe 8. As a result, it is possible to prevent insufficient discharge of the oil separated by adhering to the inner wall surface 2a of the housing 2 from the oil return pipe 8.

Further, the distance D1 from the lower end 3a of the housing body 3 to the inlet of the oil separator discharge pipe 6 and the total length L of the housing 2 are defined as D1/L≧0.45, whereby a capacity that functions as the oil separator 1 is secured. At the same time, it is possible to suppress the oil attached to the inner wall surface 2a of the housing 2 from being discharged through the discharge pipe.

Further, the reducing portion 5 has a conical shape, and the angle formed by the inner surfaces of the reducing portion 5 is set to 60° or less, whereby the slope formed by the inner surface of the reducing portion 5 becomes steep. Thereby, the oil on the inner surface of the reduction unit 5 can be made to flow easily.
Further, since the position of the lower end 6a of the oil separator discharge pipe 6 is lower than that of the refrigerant gas inflow pipe 7, it is possible to secure a distance in which the refrigerant gas swirls in the housing 2 and effectively separate the oil. You can

[Second embodiment]
Hereinafter, the oil separator 1B of the second embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, differences from the above-described first embodiment will be mainly described, and description of similar parts will be omitted.
As shown in FIG. 3, the oil return pipe 8B of the oil separator 1B of this embodiment is not on the central axis A1 of the housing 2. The oil return pipe 8B extends along the outer peripheral surface of the housing body 3. In other words, the oil return pipe 8B is connected as far as possible from the central axis A1 of the housing 2 and the central axis A3 of the oil return pipe 8B is close to the inner wall surface 2a of the housing 2. There is.

As shown in FIG. 4, when the outer diameter of the housing 2 is OD, the center axis A3 of the oil return pipe 8B of the present embodiment has a diameter OD/2 centered on the center axis A1 of the housing 2B when viewed from above. It is located outside the circle.

The reduced portion 5B of the present embodiment is formed so that the cross section orthogonal to the central axis A1 gradually becomes smaller as it goes downward. The reduced portion 5B is formed such that the cross-sectional shape orthogonal to the central axis A1 matches the housing main body 3 at the connection portion with the housing main body 3 and the oil return pipe 8B at the connection portion with the oil return pipe 8B. ing.

According to the above-described embodiment, similarly to the oil separator 1 of the first embodiment, the housing 2B is provided with the reduced portion 5B, and the oil return pipe 8B is connected so as to be close to the inner wall surface 2a of the housing 2B. By doing so, it is possible to prevent insufficient discharge of the oil separated by adhering to the inner wall surface 2a of the housing 2 from the oil return pipe 8B.

[Third embodiment]
Hereinafter, an oil separator 1C according to a third embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, differences from the above-described first embodiment will be mainly described, and description of similar parts will be omitted.
As shown in FIG. 4, the housing 2C of the oil separator 1C of the present embodiment includes a lower end plate 10 (bottom portion) connected to the lower end 3a of the housing body 3 as an alternative to the reduced portion. The lower end plate 10 has a disc shape.

The oil separator 1C of the present embodiment has two oil return pipes 8C. Each oil return pipe 8C is connected to a position as far as possible from the central axis A1 of the housing 2C. In other words, each oil return pipe 8C is connected so as to be as close as possible to the inner wall surface 2a of the housing 2C when viewed from above.

As shown in FIG. 6, the center axis A4 of each oil return pipe 8C is a circle having a diameter OD/2 centered on the center axis A1 of the housing 2C when viewed from above, where OD is the outer diameter of the housing 2C. Is located outside of. The two oil return pipes 8C are arranged so that the distance between the two oil return pipes 8C is as large as possible.

According to the above-described embodiment, the refrigerant gas containing oil swirls in the housing 2C, whereby the oil adheres to the inner wall surface 2a of the housing 2C and is separated. Next, when the oil attached to the inner wall surface 2a reaches the lower end plate 10, the oil is introduced into the oil return pipe 8 connected so as to be close to the inner wall surface 2a of the housing 2C. As a result, it is possible to prevent the oil separated by adhering to the inner wall surface 2a of the housing 2C from being insufficiently discharged from the oil return pipe 8C.

Further, the oil separator 1C has two oil return pipes 8C, and the respective oil return pipes 8C are arranged such that the distance between them is the largest, so that more oil can be transferred to the oil return pipe 8C. Can be introduced.

〔Experimental result〕
Next, of the two oil return pipes 8C of the oil separator 1 of the first embodiment, the oil separator 1C of the third embodiment, and the oil separator 1C of the third embodiment, one oil return pipe 8C is sealed. An experimental result comparing the stopped mode (referred to as a modified example of the third embodiment) and the conventional oil separator 100 shown in FIG. 7 will be described.

In FIG. 8, the horizontal axis represents the rotation speed (rpm) of the compressor 56, the vertical axis represents the oil discharge amount from the oil separator 1 (liter/hour), and the oil discharge amount from the compressor 56 (kg/hour). It is a graph which shows an experimental result. Here, the amount of oil discharged from the oil separator 1 is the amount of oil discharged from the oil separator discharge pipe 6 together with the refrigerant gas.

As can be seen from the graph of FIG. 8, the oil discharge amount from the compressor 56 increases as the rotation speed of the compressor 56 increases.
The amount of oil discharged from the conventional oil separator 100 rapidly increases when the rotation speed of the compressor 56 exceeds 100 rpm. In the conventional oil separator 100, a large amount of oil is discharged downstream together with the refrigerant gas through the oil separator discharge pipe 6 without sufficiently discharging the oil from the oil return pipe 108.

On the other hand, in the first embodiment, the third embodiment, and the modified examples of the third embodiment, the oil discharge amount from the oil separator 1 did not increase even when the rotation speed of the compressor 56 exceeded 100 rpm. That is, even when the rotation speed of the compressor 56 was increased, the oil separation efficiency was not reduced.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the oil separator 1C of the third embodiment, two oil return pipes 8C are provided, but the number is not limited to this, and three or more oil return pipes 8C are arranged near the inner wall surface 2a of the housing 2C. You may.
In the above embodiment, the housing body 3 has a cylindrical shape, but may have a tubular shape, for example, an octagonal tubular shape.

1, 1B, 1C Oil separator 2, 2B, 2C Housing 2a Inner wall surface 3 Housing body 4 Upper end plate 5, 5B Reduction section 6 Oil separator Discharge pipe (Discharge pipe)
7 Refrigerant gas inflow pipe 8, 8B, 8C Oil return pipe 10 Lower end plate (bottom)
50 Refrigeration cycle device 51 Refrigerant circuit 52 Outdoor unit 53 Indoor unit 54 Gas pipe 55 Liquid pipe 56 Compressor 57 Condenser 58 Evaporator 59 Expansion valve 60 Suction pipe 61 Compressor discharge pipe 63 Case 64 Compression element 66 Electromagnetic valve 67 Capillary pipe A1, A2, A3, A4

Claims (5)

An oil separator for separating oil contained in a refrigerant gas discharged from a compressor from the refrigerant gas,
A cylindrical housing body whose central axis extends in the vertical direction,
An upper end plate connected above the housing body,
A housing connected to the lower part of the housing body, and having a reduction part formed so that a cross section orthogonal to the central axis becomes smaller as it goes downward.
An oil return pipe connected to the lower portion of the reduction unit,
A discharge pipe extending vertically through the upper end plate,
The vertical distance between the lower end of the discharge pipe and the lower end of the housing body is D1,
When the vertical distance between the upper end of the upper end plate and the lower end of the reduced portion is L,
D1/L ≧ 0.45
Is an oil separator. The reduction portion has a conical shape,
The oil separator according to claim 1, wherein in a cross section of the reduced portion including the central axis of the reduced portion, an angle formed by inner surfaces of the reduced portion is 60° or less. When the outer diameter of the housing is OD, the central axis of the oil return pipe is arranged outside a circle having a diameter OD/2 centered on the central axis of the housing when viewed from above. Item 3. The oil separator according to item 2. An oil separator for separating oil contained in a refrigerant gas discharged from a compressor from the refrigerant gas,
A cylindrical housing body whose central axis extends in the vertical direction,
An upper end plate connected above the housing body,
A housing having an upper end plate connected below the housing body;
An oil return pipe connected to the bottom of the housing,
A discharge pipe extending vertically through the upper end plate,
When the outer diameter of the housing is OD, the central axis of the oil return pipe is arranged outside a circle having a diameter OD/2 centered on the central axis of the housing when viewed from above. The oil separator according to claim 4, wherein the oil separator has two or more oil return pipes, and the respective oil return pipes are arranged such that a distance between them is greatest.

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