JP2013053568A - Oil separator and compressor including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator having a good separating efficiency that separates oil from coolant gas by a centrifugal force, and a compressor.SOLUTION: The oil separator, which centrifugally separates oil from a coolant mixed with the oil discharged from a compression mechanism part of a coolant compressor, recirculates the separated oil into the coolant compressor, and discharges the separated coolant outside, is characterized in that a separating pipe part constituted of a discharge part and an intake part keeps the discharge part fitted to an inner wall face of a separator housing, so that an inner diameter of the inner wall face of the separator housing is enlarged within a range from an intake hole central axis position to a part corresponding to an end part of the intake part.

Description

  The present invention relates to an oil separator that separates oil in refrigerant gas by centrifugal force, and a compressor including the oil separator. In particular, the oil is centrifuged from the oil-mixed refrigerant discharged from the compressor mechanism of the refrigerant compressor, the separated oil is recirculated to the refrigerant compressor, and the separated refrigerant is discharged to the outside. The present invention relates to an oil separator and a compressor including the oil separator.

  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.

  There exists patent document 1 as such a prior art. This is to separate the oil from the refrigerant containing oil discharged from the compressor by centrifugal force, but the oil attached to the cylindrical inner wall surface of the separator housing by centrifugal force is wound up by the gas flow near the separation pipe. There has been a problem of being discharged with the refrigerant.

  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.

Japanese Patent No. 4381458

  In the present invention, in view of the above problem, the centrifugal separator that requires centrifugal force reduces the inner diameter of the cylindrical separator housing so as to increase the swirling flow velocity of the refrigerant, and sucks the refrigerant that has turned into a turn flow after separation. The refrigerant suction part (end part of the separation pipe part) includes an oil separator that increases the inner diameter of the separator housing so as to reduce the flow rate of the refrigerant so as to reduce the winding of the oil attached to the wall surface, and the oil separator The compressor provided with this is provided.

  In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that oil is centrifuged from oil-mixed refrigerant discharged from the compression mechanism (57) of the refrigerant compressor, and the separated oil is supplied to the refrigerant compressor. An oil separator that recirculates and discharges the separated refrigerant to the outside, and the oil separator has an oil storage chamber (93) having an oil feed port (87) for recirculation to the refrigerant compressor. ), A suction hole (23) through which the refrigerant discharged from the compression mechanism (57) flows in from the tangential direction of the cylindrical inner wall surface of the separator housing (17), and a gas discharge port (18) for discharging the refrigerant to the outside ) And a separator housing (17) having an opening (17b) communicating with the oil storage chamber (93), and a separation pipe portion (19) comprising a discharge portion (19a) and a suction portion (19b) The discharge portion (19a) is fitted or installed on the inner wall surface of the separator housing (17), communicates with the gas discharge port (18), and the suction portion (19b) has an outer diameter of the separator housing. A separation pipe portion (19) having a cylindrical shape smaller than the inner wall surface inner diameter and having an end portion of the suction portion (19b) opened in the separator housing to the oil storage chamber side from the suction hole (23). The oil separator is characterized in that an inner diameter of the inner wall surface increases in a range from a position of the suction hole (23) central axis to a portion corresponding to the end of the suction portion (19b).

  In order to suppress the re-scattering of oil from the wall surface near the end of the suction part, the inner diameter of the inner wall surface of the separator housing near the end of the suction part is enlarged to reduce the flow velocity. As a result, the oil adhering to the cylindrical inner wall surface of the separator housing is rolled up by the gas flow when being reversed and discharged to the outside, and is not discharged together with the refrigerant, so that the oil peeling due to the swirling flow is reduced, The oil rate can be reduced. Moreover, since the heat exchange efficiency of the heat exchanger is improved by reducing the oil rate, the system efficiency COP can be improved.

  According to a second aspect of the present invention, in the first aspect of the present invention, the inner diameter of the inner wall surface of the separator housing ranges from the position of the central axis of the suction hole (23) to the portion corresponding to the end of the suction portion (19b). It has a two-stage inner diameter. Thereby, the separation efficiency can be improved.

  According to a third aspect of the present invention, in the second aspect of the invention, the inner diameter of the inner surface of the separator housing is determined from the inner diameter D1 in a cross section including the central axis of the suction hole (23) and the position of the central axis of the suction hole (23). The relationship with the inner diameter D2 of the cross section changed in the range up to the portion corresponding to the end of the suction portion (19b) is in the range of 1.1 ≦ D2 / D1 ≦ 1.5. Thereby, the separation efficiency can be improved.

According to a fourth aspect of the present invention, in the third aspect of the invention, from the inner diameter D1, the inner diameter D2, and a position corresponding to the end of the suction portion (19b) from a position where the inner diameter D1 changes to the inner diameter D2. The relationship with the distance L2 in the central axis direction of the inner wall surface of
7 ≦ L2 / ((D2−D1) / 2) ≦ 22. Thereby, the separation efficiency can be improved.

  According to a fifth aspect of the present invention, the inner diameter (D1) of the inner wall surface in a cross section including the flow path cross-sectional area A0 of the suction hole (23), the outer diameter of the suction portion (19b), and the central axis of the suction hole (23). A cross-sectional area A1 of the annular space between and the distance L1 in the direction of the central axis of the inner wall surface from the position of the central axis of the suction hole (23) to the position where the inner wall surface inner diameter (D2) has been enlarged. The relationship is in the range of 7 <L1 × (A1 / A0) <110. Thereby, compared with the case of D1 whose inner wall surface inner diameter does not change in two steps, the separation efficiency ratio is improved.

  According to a sixth aspect of the present invention, in the invention according to any one of the second to fifth aspects, the inner diameter of the inner wall surface of the separator housing extends from the central axis position of the suction hole (23) in the central axis direction of the inner wall surface. In the range up to the portion corresponding to the end of the inhalation part (19b), it gradually expands. In this case, since the inner wall surface inner diameter gradually increases while having two steps, the separation efficiency can be further improved.

  A seventh aspect of the present invention is a compressor including the oil separator according to any one of the first to sixth aspects.

  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.

(A) is sectional drawing which shows the oil separator of one Embodiment of this invention, and the compressor to which it is applied, (b) is a cross-sectional view regarding the AA line of (a). (A) is explanatory drawing of the centrifugal oil separator of a prior art, (b) is explanatory drawing of the oil separator of one Embodiment of this invention. It is the graph showing the internal diameter ratio of the cylinder inner wall surface of the oil separator of one embodiment of the present invention, and the effect of the separation efficiency with respect to the step position, (a) is an explanatory diagram of the dimensions, (b) is the internal diameter The relationship between the ratio D2 / D1 and the separation efficiency is shown, and (c) shows the relationship between the inner diameter ratio, the step position and the separation efficiency. It is explanatory drawing of the oil separator which shows other embodiment of this invention. It is the graph showing the separation efficiency ratio which compared the prior art and one Embodiment of this invention.

  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 a method of centrifuging oil from a refrigerant mixed with oil discharged from a compression mechanism portion of a refrigerant compressor, recirculating the separated oil to the refrigerant compressor, and after separation. This is an oil separator that discharges the refrigerant to the outside.
Such an oil separator according to the present embodiment is different in function from a gas-liquid separator (tank) that separates lubricating oil from refrigerant used in a refrigeration cycle. Since the gas-liquid separator in the conventional refrigeration cycle is required to have a function as a tank, the cross-sectional area is large in the tank, and gas-liquid separation is performed under a low flow rate of about 0.1 to 1 m / sec. The

  The oil separator according to the present embodiment performs centrifugal separation by turning at a high speed of about 5 to 10 m / sec in order to pursue high separation efficiency. For this reason, it is an object of the present invention to improve the point that the oil adhering to the cylindrical inner wall surface of the separator housing is rolled up by the gas flow when being reversed and discharged to the outside and discharged together with the refrigerant. That is, it is an object to reduce oil separation at the oil separation portion due to the high-speed swirling flow.

Fig.1 (a) is sectional drawing which shows the oil separator of one Embodiment of this invention, and the compressor to which it is applied, (b) is a cross-sectional view regarding the AA line of (a).
The oil separator according to one embodiment of the present invention is not limited to the refrigerant compressor of FIG. 1, and is not limited to a scroll type compressor, but other types of compressors (rolling piston type, slide vane type, The present invention may be widely applied to a reciprocating type oil separator. The oil separator according to one embodiment of the present invention is not limited to a vertical type, and may be a compressor having a horizontal type. The oil storage section 85 is not limited to the outside of the sealed container 53 but may be applied to a type installed inside. In addition, the oil separator of one embodiment of the present invention improves the separation efficiency not only when the oil separator is applied to a compressor using a CO2 refrigerant but also when other refrigerants are used. The present invention can be applied to an oil separator for a compressor such as a heat pump unit (water heater) such as a chlorofluorocarbon refrigerant CO2 or a vehicle air conditioner.

Hereinafter, a refrigerant compressor to which an oil separator according to an embodiment of the present invention is applied will be described as an example.
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 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 Rotation is performed by the shaft 75 of the electric motor unit 55 that is vertically supported by the main bearing 65 and the sub bearing 73. The motor rotor motor 55 ′ is attached to the shaft 75, and the stator motor 55 ″ is attached to the first housing 59.

  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 (suction chamber not shown) communicating with the side is configured to be compressed. A discharge chamber 81 communicates with the working chamber 77 of the compression mechanism 57 through a discharge hole 79, and one end of an intake pipe 25 of an oil separator is connected to the discharge chamber 81 (not shown). The other end of the suction pipe 25 is connected to a suction hole 23 provided in the separator housing 17 of the oil separator. The separator housing 17 is formed in a cylindrical shape. A gas discharge port 18 is provided in the upper opening of the separator housing 17. The separation pipe portion 19 includes a large-diameter portion (a gas discharge port 18) 19a that is a discharge portion that fits into the upper opening of the separator housing 17, and a suction portion that is formed below the large-diameter portion 19a. And a small diameter portion 19b. The large diameter portion 19a may be formed in the separator housing 17 itself. In this case, the pipe is fitted with the small diameter portion 19b.

One end of the oil feeding pipe 33 is connected to an oil feeding port 87 provided at the bottom of the oil storage chamber 93. The refrigerant is discharged from the compression mechanism 57 to the discharge chamber 81 and supplied to the oil separator through the inflow pipe 25. The suction port 23 is provided in the cylindrical inner wall surface of the separator housing 17, and the refrigerant mixed with oil flows in from the tangential direction of the cylindrical inner wall surface. The oil 1 is separated by rotating in the space (annular space) between the cylindrical inner wall surface of the separator housing 17 and the small diameter portion 19b, and the refrigerant is sent from the gas discharge port 18 to the external refrigerant circuit, while the oil is Then, it flows down to the oil storage chamber 93. The oil stored in the oil storage chamber 93 is returned from the oil supply port 87 to the refrigerant compressor through the oil supply pipe 33 and supplied to a sliding portion such as a sliding surface of the fixed and rotary scroll.
The refrigerant from which the swirling oil 1 is separated in the space between the cylindrical inner wall surface of the separator housing 17 and the small diameter portion 19b is sucked into the separation pipe portion 19 through the small diameter portion 19b, and is piped from the gas discharge port 18 (see FIG. (Not shown).

Next, main features of the oil separator according to one embodiment of the present invention will be described.
FIG. 2A is an explanatory diagram of a conventional centrifugal oil separator, and FIG. 2B is an explanatory diagram of an oil separator according to an embodiment of the present invention.
The prior art in FIG. 2 (a) separates oil by centrifugal force from a refrigerant containing oil discharged from a compressor. The oil having a high specific gravity adheres to the cylindrical inner wall surface of the separator housing by centrifugal force, but the oil film is sheared by the gas flow near the end S of the small diameter portion 19b, and the oil is scattered again. The oil adhering to the inner wall surface K of the separator housing due to centrifugal force is wound up by the gas flow in the vicinity of the small-diameter end S of the separation pipe portion 19 and is discharged to the outside together with the refrigerant. Moreover, if the inner diameter of the cylindrical inner wall surface of the centrifugal separation portion (inner wall surface K) is increased in order to reduce the gas swirling flow rate, the centrifugal force is insufficient and the separation efficiency decreases.

  On the other hand, in the oil separator according to the embodiment of the present invention shown in FIG. 2B, paying attention to the re-scattering of oil from the wall surface in the vicinity of the end S of the small diameter portion 19b, the end of the small diameter portion 19b. Only in the vicinity of S, the inner diameter of the inner wall surface of the cylinder is enlarged and the flow velocity is lowered. Specifically, as shown in FIG. 2B, the inner diameters of the cylindrical inner walls of the centrifugal separation unit 17 'and the flow velocity reduction unit 17' 'are configured to be stepped.

FIG. 3 is a graph showing the effect of the separation efficiency on the inner diameter ratio of the cylindrical inner wall surface of the oil separator and the uneven position of the oil separator according to the embodiment of the present invention, (a) is an explanatory diagram of the dimensions, ) Is experimental data showing the relationship between the inner diameter ratio D2 / D1 and the separation efficiency, and (c) is experimental data showing the relationship between the inner diameter ratio, the step position and the separation efficiency.
Here, D <b> 1 is an inner diameter in a cross section including the center of the suction hole 23 in the inner wall surface inner diameter of the separator housing 17. D2 is the inner diameter of the cross section changed in the range from the center of the suction hole 23 to the portion S corresponding to the end of the small diameter portion 19b, that is, the cylindrical inner wall surface of the enlarged flow velocity reduction portion 17 ″ in the case of FIG. The inner diameter. The graph of FIG. 3 shows the separation efficiency in the case of the CO2 refrigerant, but substantially the same result can be obtained with the refrigerant in other cases. In addition, the outer diameter of the small diameter part 19b of the separation pipe part is about 0.6 to 0.7D1.

As shown in the result of FIG. 3, the inner diameter of the inner wall surface of the separator housing 17 changed in the range from the inner diameter D1 in the cross section including the center of the suction hole 23 to the portion corresponding to the end of the small diameter portion 19b from the center of the suction hole 23. In the range of 1.1 ≦ D2 / D1 ≦ 1.5 in relation to the inner diameter D2 of the cross section, extremely good separation efficiency is shown.
In addition, the relationship between the inner diameter D1, the inner diameter D2, and the distance L2 in the direction of the central axis of the inner wall surface from the position where the inner diameter D1 changed to the inner diameter D2 to the portion corresponding to the end of the small diameter portion 19b,
In the range of 7 ≦ L2 / ((D2−D1) / 2) ≦ 22, extremely good separation efficiency is shown. From this experimental result, when the target value of the oil separation efficiency is 99%, D2 / D1 needs to be in the range of 1.1 to 1.5, and L2 / ((D2-D1) / 2) is 7 to It is necessary to be within a range of 22 (note that the hatched portions in FIGS. 3B and 3C indicate a 99% region).

  Furthermore, the flow path cross-sectional area A0 of the suction hole 23 is defined as the flow path cross-sectional area A1 between the outer diameter of the small diameter portion 19b and the inner wall surface inner diameter D1 in the cross section including the central axis of the suction hole 23. When the distance L1 in the central axis direction of the inner wall surface from the shaft position to the position where the inner wall surface inner diameter D2 is changed to the enlarged inner wall surface diameter D2, the relationship is shown in the range of 7 <L1 × (A1 / A0) <110. As shown in FIG. 4, the separation efficiency ratio is improved. Here, the separation efficiency ratio in FIG. 4 is the ratio of the present embodiment compared to the case of D1 where the inner wall surface inner diameter does not change in two steps. The separation efficiency is a percentage of (Min−Mout) / Min, where Min is the amount of oil flowing in from the suction hole 23 and Mout is the amount of oil flowing out from the gas discharge port 18.

The effect of the oil separator according to one embodiment of the present invention over the prior art of FIG. 2A is that, as described above, extremely good separation efficiency can be obtained (both inner diameters D1 are the same). In the shape of the prior art, the oil separation efficiency is 97.5%, whereas in one embodiment of the present invention, the efficiency is improved to 99.5%. If this is seen by oil discharge amount, it will be reduced from 2.5% to 0.5%, and the discharge amount will be reduced by 80%. The system oil rate can be reduced in a CO ₂ heat pump unit (CO ₂ water heater) equipped with the oil separator of one embodiment of the present invention. Since the heat exchange efficiency of the heat exchanger is improved by reducing the system oil rate, the system COP (coefficient of performance) can be improved.

In another embodiment of the present invention, the inner diameter of the inner wall surface of the separator housing is gradually gradually increased as a whole from the center of the suction hole 23 to the portion corresponding to the end of the small diameter portion 19b in the central axis direction of the inner wall surface. You may make it expand to. Alternatively, the inner diameter may be gradually increased in each of the two steps. Moreover, the oil separator of the embodiment of the present invention can be applied to various compressors.
As another embodiment of the present invention, as shown in FIG. 4, a pipe portion having a constant diameter may be used as the separation pipe portion of the oil separator.

DESCRIPTION OF SYMBOLS 17 Separator housing 17b Opening part 18 Gas discharge port 19 Separation pipe part 19a Discharge part, large diameter part 19b Suction part, small diameter part 23 Suction hole 57 Compression mechanism part 87 Oil supply port 93 Oil storage chamber

Claims (7)

The oil is centrifuged from the oil-mixed refrigerant discharged from the compression mechanism section (57) of the refrigerant compressor, and the separated oil is recirculated to the refrigerant compressor, and the separated refrigerant is discharged to the outside. An oil separator, wherein the oil separator is
An oil storage chamber (93) having an oil supply port (87) for recirculation to the refrigerant compressor;
A suction hole (23) through which the refrigerant discharged from the compression mechanism (57) flows in from a tangential direction of the cylindrical inner wall surface of the separator housing (17), a gas discharge port (18) for discharging the refrigerant to the outside, and A separator housing (17) having an opening (17b) communicating with the oil storage chamber (93);
A separation pipe part (19) composed of a discharge part (19a) and a suction part (19b), the discharge part (19a) being fitted or installed on the inner wall surface of the separator housing (17), The suction port (18) communicates with the discharge port (18) so that the outer diameter of the suction portion (19b) is smaller than the inner diameter of the inner wall surface of the separator housing, and the end portion of the suction portion (19b) is within the separator housing. A separation pipe part (19) opened to the oil storage chamber side,
An oil separator characterized in that the inner diameter of the inner wall surface of the separator housing expands in a range from the position of the central axis of the suction hole (23) to a portion corresponding to the end of the suction portion (19b).   The inner diameter of the inner wall surface of the separator housing has a two-stage inner diameter in a range from the central axis position of the suction hole (23) to a portion corresponding to the end of the suction portion (19b). The oil separator according to 1. In the inner diameter of the inner wall of the separator housing, an inner diameter D1 in a cross section including the central axis of the suction hole (23) and a range from the position of the central axis of the suction hole (23) to a portion corresponding to the end of the suction part (19b) The relationship with the inner diameter D2 of the cross section changed by
1.1 ≦ D2 / D1 ≦ 1.5
The oil separator according to claim 2, wherein the oil separator is in the range. Relationship between the inner diameter D1, the inner diameter D2, and the distance L2 in the central axis direction of the inner wall surface from the position changed from the inner diameter D1 to the inner diameter D2 to the portion corresponding to the end of the suction portion (19b) But,
7 ≦ L2 / ((D2-D1) / 2) ≦ 22
The oil separator according to claim 3, wherein the oil separator is in the range. The cross-sectional area A0 of the suction hole (23),
A channel cross-sectional area A1 of an annular space between the outer diameter of the suction portion (19b) and the inner wall surface inner diameter (D1) in a section including the central axis of the suction hole (23);
The relationship with the distance L1 in the direction of the central axis of the inner wall surface from the position of the central axis of the suction hole (23) to the position where the inner wall surface inner diameter (D2) is increased.
7 <L1 × (A1 / A0) <110
The oil separator according to any one of claims 2 to 4, wherein the oil separator is in the range.   The inner diameter of the inner wall surface of the separator housing gradually increases in the direction of the central axis of the inner wall surface from the position of the central axis of the suction hole (23) to the portion corresponding to the end of the suction section (19b). The oil separator according to any one of claims 2 to 5, wherein:   A compressor comprising the oil separator according to any one of claims 1 to 6.