JP2009109102A - Oil separator and refrigerant compressor provided with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil separator separating oil from CO<SB>2</SB>refrigerant in high separation efficiency, and also to provide a refrigerant compressor provided with the separator. <P>SOLUTION: The oil separator 30 includes: a chamber 35 formed by a cylindrical inner wall face 34b; an inlet 32 opened in the inner wall face 34b, and an inflow pipe 31 connected to the inlet 32 and elongated in a substantially tangent direction of the inner wall face 34b. It is also provided with: a separating part 33 separating oil in a coolant by turning the coolant flowing into the chamber 35 from the inlet 32 by centrifugal force, and having a discharge passage 43 discharging remaining coolant after oil separation; and an oil storage part 37 connected to the chamber 35 and storing the separated oil. A value L/ϕD of dividing a distance L from an inlet 42 of the discharge passage to a bottom 34a of the chamber by an inner diameter ϕD of the inner wall face 34b is 2.5 or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oil separator that separates oil (lubricating oil) from a refrigerant that flows through a refrigeration cycle, and a refrigerant compressor that includes the oil separator.

  In general, the oil separator separates oil mixed in the refrigerant from the refrigerant, supplies the oil to the bearings and sliding parts of the compressor of the refrigeration cycle, lubricates them, and discharges them together with the refrigerant gas to the refrigeration cycle. An appropriate amount of oil is prevented to prevent a decrease in the coefficient of performance (COP) of the refrigeration cycle.

As such a conventional oil separator, a so-called centrifugal mechanism is known (for example, see Patent Document 1). This conventional oil separator includes a separation chamber that centrifuges oil from gas compressed on the discharge side of the compression mechanism, an oil storage chamber that stores the separated oil and then supplies it to a bearing portion, and the upper part of the separation chamber And an outlet pipe for discharging the separated refrigerant gas to the refrigeration cycle.
Japanese Patent Laid-Open No. 3-129273

In recent years, it has been demanded to use a CO ₂ refrigerant from the viewpoint of environmental problems. However, since the CO ₂ refrigerant has a characteristic that the density difference from the lubricating oil is small, the oil separator described in Patent Document 1 has sufficient oil separation due to, for example, the oil rolling phenomenon in the separation chamber. There was a problem that it was not done.

  If the oil is not sufficiently separated, the oil rate in the refrigerant discharged to the refrigeration cycle increases, and high heat exchange performance in the heat exchanger cannot be obtained, resulting in a decrease in the coefficient of performance. In contrast, sufficient oil cannot be supplied, and the reliability of the compressor in operation is lowered.

The present invention has been made in view of the above problems, and an object thereof is to provide an oil separator capable of separating oil from a CO ₂ refrigerant with high separation efficiency and a refrigerant compressor including the same.

The present invention employs the following technical means to achieve the above object. The first invention includes a chamber (35) surrounded by an inner wall surface (34b) formed in a cylindrical shape, an inflow port (32) opened to the inner wall surface (34b), and an inflow port (32). An inflow passage (31) extending substantially in the tangential direction of the wall surface (34b) is provided, and the refrigerant flowing into the chamber (35) from the inlet (32) is swirled by centrifugal force along the inner wall surface (34b). The oil mixed in the refrigerant is separated, and further, the separation part (33) having a discharge passage (43) through which the remaining refrigerant separated from the oil is discharged, and the separated oil connected to the chamber (35) And an oil separator (30) provided in a refrigeration cycle (115) in which a refrigerant mainly containing CO ₂ circulates.
The value (L / φD) obtained by dividing the distance L from the inlet (42) of the discharge passage to the bottom (34a) of the chamber by the inner diameter φD of the inner wall surface (34b) is 2.5 or more. Yes.

  According to this invention, the oil separator which can implement | achieve the outstanding oil-separation efficiency by suppressing winding-up of the isolate | separated oil can be provided. Also, by improving the oil separation efficiency, sufficient oil can be stored in the oil storage section, and therefore the compressor can be sufficiently lubricated, and the reliability in operating the compressor can be improved. it can. Moreover, since sufficient oil can be stored in the oil storage part, discharge pulsation can be reduced.

  In addition, a refrigerant compressor provided integrally with the oil separator (30) described in the above invention can be employed. According to the present invention, since the path from the compression mechanism portion to the oil separator is shortened, the pressure loss is reduced and the oil separation efficiency can be increased.

  Furthermore, a refrigerant compressor having a compression mechanism part (57) in a low-pressure vessel (53) that forms a low-pressure space therein can be employed. As a result, since the pressure around the compression mechanism is low, the container cannot be used as an oil separator. By providing the oil separator, the reliability can be improved. In addition, by integrating the oil separator with the compressor, the overall size can be reduced.

Moreover, this refrigerant compressor is used for the heat pump cycle for hot water heaters. Therefore, even in a heat pump using a CO ₂ refrigerant, the oil can be sufficiently separated, the COP of the heat pump can be improved, and the lubricity of the high-load sliding portion inherent to CO ₂ can be improved. Can be ensured, and the reliability of the apparatus can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means of embodiment mentioned later.

  Hereinafter, a plurality of modes for carrying out the present invention will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The oil separator 30 according to the present embodiment appropriately adjusts the amount of oil that circulates in the refrigeration cycle by separating oil from the refrigerant mainly composed of CO ₂ in order to suppress a decrease in cooling performance. The oil separated from the refrigerant is used to supply oil (lubricating oil) to the bearings and sliding parts of the compressor.

  This refrigeration cycle is, for example, a heat pump cycle, and can be applied to a water heater or a vehicle air conditioner. In this embodiment, an example in which the oil separator 30 is applied to a heat pump cycle for a hot water heater that heats hot water for supplying water to a bath, a shower, a kitchen, a washroom, and the like will be described later.

  FIG. 1 is a cross-sectional view showing a configuration of an oil separator 30 in which a separation part 33 is arranged in the upper part and an oil storage part 37 is arranged in the lower part. As shown in FIG. 1, the oil separator 30 has a double pipe structure composed of an inner wall surface 34 b that forms a chamber 35 that is a cylindrical inner space of the separation portion 33 and a cylindrical discharge pipe 41.

  The oil separator 30 includes a separation unit 33 that separates oil mixed in the refrigerant by centrifugal force, and an oil storage unit 37 that stores the oil separated by the separation unit 33. The separation part 33 is connected to the discharge part of the compressor 1 by the inflow pipe 31. The discharge passage 43 through which the refrigerant (residual refrigerant) after the oil is separated by the separation unit 33 flows out is connected to another device (for example, a water-refrigerant heat exchanger) in the refrigeration cycle by a pipe. The oil storage part 37 is connected to the compressor 1 by an oil feeding pipe 40 and communicates with a bearing part and a sliding part of the compressor 1.

  The separation unit 33 is a cylindrical container 34, an inflow pipe 31 connected to the cylindrical container 34 on the outer peripheral surface of the upper part of the cylindrical container 34, and a discharge that is fitted into the upper end opening of the cylindrical container 34. A tube 41.

  The chamber 35 formed inside the cylindrical container 34 is surrounded by a cylindrical inner wall surface 34b of the cylindrical container 34, and serves as a separation chamber in which oil is separated from the refrigerant flowing therein. The cylindrical container 34 is formed so that the inner diameter dimension is substantially constant from the upper part to the lower part. The cylindrical container 34 has a chamber bottom 34a at the lower portion, and a communication hole 36 having a small diameter is formed in the chamber bottom 34a. The communication hole 36 is a constricted portion provided in a portion extending from the chamber 35 to the oil storage portion 37, has a cross-sectional area narrower than that of the chamber 35, and oil separated in the chamber 35 accumulates on the surface of the bottom 34a of the chamber. After that, it becomes a road that flows down toward the oil storage section 37.

  The refrigerant injected from the inlet 32 into the chamber 35 passes through the annular space between the outer peripheral surface of the lower small-diameter portion 41a and the inner wall surface 34b of the cylindrical container 34 at the portion where the inlet 32 is disposed at high speed. Turn. The oil having a high specific gravity is attached to the inner wall surface 34b of the cylindrical container 34 by the centrifugal force generated by the high-speed rotation, and the refrigerant and the oil are separated.

  The oil storage part 37 provided in the lower part of the separation part 33 has an oil storage tank 38 which is a bottomed cylindrical box body, and a cylindrical container 34 is connected to the upper part of the oil storage tank 38, and the oil storage tank An oil feed pipe 40 is connected to an oil feed port 38 a that opens to the bottom of the 38. An oil storage chamber 39 in the internal space formed by the oil storage tank 38 communicates with the chamber 35 via the chamber bottom 34a.

  In the oil separator 30 having the above configuration, when the distance from the inlet 42 of the discharge passage to the bottom 34a of the chamber is L and the inner diameter of the inner wall surface 34b is φD, a value obtained by dividing L by φD between the two The relationship that (L / φD) is 2.5 or more is satisfied.

Since the CO ₂ refrigerant used in the present embodiment has a higher density than the HFC-134a refrigerant, the density difference from the oil is reduced. Therefore, the difference between the centrifugal force acting on the refrigerant and the oil becomes small, and the separated oil is easily attracted by the refrigerant. Therefore, L / φD needs to be sufficiently increased. At L / φD equivalent to the case where a refrigerant such as HFC-134a is used, separation efficiency is reduced due to oil winding, which causes a decrease in compressor reliability due to insufficient lubrication and a decrease in the coefficient of performance of the refrigeration cycle. It is.

  Therefore, by configuring the separation unit 33 so as to satisfy the above relationship (L / φD ≧ 2.5), sufficient oil separation efficiency can be ensured. The reason for adopting the above relationship will be described below with reference to FIG. FIG. 2 is a graph showing the relationship between L / φD and oil separation efficiency based on data obtained through experiments.

As shown in FIG. 2, the separation efficiency curve of HFC-134a is almost flat when L / φD is 1 or more, whereas the separation efficiency curve of CO ₂ is from 0 to 2 in L / φD. It rises sharply in the process of approaching, and the gradient of rise rises sharply in the vicinity of 2.5, almost flat at 4 and above, and gradually approaches the maximum separation efficiency. From the above experimental results, by configuring the separation unit to satisfy L / φD ≧ 2.5, the oil rate in the CO ₂ refrigeration cycle can be reduced and the system COP can be improved, and the compressor is sufficient. Oil can be supplied to the tank, and the reliability can be improved. Further, sufficient oil can be stored in the oil storage section, and discharge pulsation can be reduced.

  Next, the hot water storage type hot water supply apparatus 111 using the heat pump cycle 115 for the hot water heater to which the oil separator 30 is applied will be described. The hot water storage type hot water supply apparatus 111 mainly includes a hot water storage tank 113, a heat pump cycle 115, and a control device 117.

  The hot water storage tank 113 can retain hot water for hot water supply, and an introduction pipe 121 for introducing tap water into the hot water storage tank 113 is connected to the bottom surface of the hot water storage tank 113. The introduction pipe 121 is provided with a thermistor 123 so that temperature information of tap water flowing through the introduction pipe 121 is output to the control device 117.

  On the other hand, a lead-out pipe 127 for leading out hot water in the hot water storage tank 113 is connected to the uppermost part of the hot water storage tank 113. A tap water supply pipe 129 is connected to the outlet pipe 127, and a mixing valve 131 is disposed at a junction with the water supply pipe 129. Then, by adjusting the mixing ratio of hot water from the hot water storage tank 113 and tap water, hot water of an appropriate temperature is supplied to a shower, a bath, etc. on the downstream side.

  In addition, a cold water outlet 133 is provided at the lower part of the hot water storage tank 113, and a hot water inlet 135 through which hot water flows into the hot water storage tank 113 is provided at the upper part of the hot water storage tank 113. The cold water outlet 133 and the hot water inlet 135 are connected by a circulation circuit 137, and a pump 139 and a water heat exchanger 141 of the heat pump cycle 115 are connected in series to the circulation circuit 137. And the cold water of the hot water storage tank 113 lower part is circulated by the pump 139, is heated with the water heat exchanger 141, and returns to the hot water storage tank 113.

  Further, a plurality of thermistors 143 are arranged in the vertical direction on the outer wall surface of the hot water storage tank 113, and temperature information at each water level in the hot water storage tank 113 is output to the control device 117.

The heat pump cycle 115 is a heating means using CO ₂ as a refrigerant, and an outdoor heat exchanger 151 having an electric compressor 145, a water heat exchanger 141, an expansion valve 147, and a blower 149 is connected by a refrigerant pipe 153 in this order. And constitutes a closed circuit. The electric compressor 145 is connected to an inverter 155 so that the electric power supplied to the electric compressor 145 can be varied. The outdoor heat exchanger 151 is provided with an outside air temperature sensor 157, and outputs temperature information of the outside air flowing into the outdoor heat exchanger 151 to the control device 117.

The electric compressor 145 of such a heat pump cycle 115 is connected to the oil separator 30 and has a configuration in which a compression mechanism is housed in a low-pressure container, and is the same as the refrigerant compressor 100 of the second embodiment to be described later. It has a configuration. Therefore, oil can be efficiently separated from the CO ₂ refrigerant passing through the electric compressor 145, and the efficiency of the entire heat pump cycle 115 can be improved.

  In this heat pump cycle 115, the refrigerant is heated to high temperature and high pressure by the electric compressor 145 and sent to the water heat exchanger 141, where the cold water (tap water) supplied from the hot water storage tank 113 is heated and boiled to hot water of a predetermined temperature. The hot water is returned to the hot water storage tank 113. The outdoor heat exchanger 151 absorbs heat from the outside air with respect to the refrigerant radiated by the water heat exchanger 141. In a heat pump cycle for a water heater, high-temperature and high-pressure refrigerant exchanges heat with water, which has a larger specific heat than air, so heat exchange performance is improved by oil separation compared to a cycle that exchanges heat with air, such as a car air conditioner. The improved effect is about 4 times greater.

  The control device 117 mainly controls the operation of the electric compressor 145 and the pump 139. The controller 117 receives temperature information from the outside air temperature sensor 157 and temperature information from the thermistors 123 and 143. Further, the temperature and water level information from the plurality of thermistors 143 are input to the control device 117. And based on these information, the electric compressor 145 and the pump 139 are appropriately driven, and hot water of a predetermined temperature and a predetermined amount or more is supplied to the hot water storage tank 113.

As described above, the hot water storage type hot water supply device 111 includes the hot water storage tank 113, the heat pump cycle 115, and the control device 117. The heat pump cycle 115 uses the CO ₂ refrigerant and has the electric compressor 145 having the oil separator 30. In addition, in the heat pump cycle for hot water heaters in particular, the high-temperature and high-pressure refrigerant exchanges heat with water having a large specific heat compared to air, so that the effect of improving the heat exchange performance by oil separation is large. A heat pump using _two refrigerants can be driven with high efficiency, and therefore, an efficient hot water storage hot water supply apparatus can be realized.

  The electric compressor 145 is not limited to the internal low pressure type, and may be another type such as an internal high pressure.

(Second Embodiment)
In the second embodiment, the refrigerant compressor 100 will be described with reference to FIG. The refrigerant compressor 100 is a scroll type compressor, and houses an electric motor portion 55 and a compression mechanism portion 57 in a sealed container 53, compresses refrigerant from an external refrigerant circuit, and is integrated with one end thereof. The oil is separated from the refrigerant compressed by the oil separator 30 attached to the oil separator, and the refrigerant is sent to an external refrigerant circuit, while the separated oil is returned to the movable part such as the compression mechanism 57. . Since the oil separator 30 included in the refrigerant compressor 100 has the same basic configuration as the oil separator 30 described in the first embodiment, the same reference numerals are given to the same components.

  The airtight container 53 of the refrigerant compressor 100 is coupled to a cylindrical first housing 59, a bottomed cylindrical second housing 61 coupled to the left end of the first housing 59, and a right end of the first housing 59. And a third housing 63 having a bottomed cylindrical shape. The sealed container 53 forms a so-called internal low-pressure container in which the pressure therein is lower than the discharge pressure of the refrigerant.

  The compression mechanism portion 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 that is horizontally supported 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 periphery of the spiral groove of the fixed scroll 71. The refrigerant supplied to a suction chamber (not shown) communicating with the side is compressed. A discharge chamber 81 communicates with the working chamber 77 of the compression mechanism 57 through a discharge port 79, and one end of the inflow pipe 31 of the oil separator 30 is connected to the discharge chamber 81. The other end of the inflow pipe 31 is connected to an inlet 32 provided in the separation portion 33 of the oil separator 30.

  An oil return passage 83 is formed on the lower side of the fixed scroll 71 in the figure, and an oil feed pipe 40 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 40 is connected to an oil feeding port 38 a provided at the bottom of the oil storage part 85.

  The oil separator 30 described in the present embodiment is a member in which the oil storage container 89 of the oil storage section 85 closes the right end of the sealed container 53 of the refrigerant compressor 100 with respect to the oil separator 30 described in the first embodiment. The third housing 63 is different from the third housing 63 in that it is formed from a substantially disk-shaped fourth housing 91 joined to a stepped portion formed at the end of the third housing 63. In connection with this, the cylindrical container 34 of the separation portion 33 is coupled through the upper portion of the third housing 63.

  The oil separator 30 of the refrigerant compressor 100 operates in the same manner as the oil separator 30 of the first embodiment, and the refrigerant supplied from the discharge chamber 81 adjacent to the compression mechanism 57 through the inflow pipe 31 is swirled in the chamber 35. Thus, the oil is separated and the refrigerant is sent out from the discharge passage 43 to the system side, while the oil flows down from the communication hole 36 to the oil storage chamber 93. The oil stored in the oil storage chamber 93 is returned to the oil return passage 83 from the oil supply port 38 a through the oil supply pipe 40 and supplied to the sliding portion such as the sliding interface between the fixed scroll 71 and the movable scroll 69.

Thus, in this refrigerant compressor 100, by integrating the oil separator 30 with the compressor, the path from the compression mechanism 57 to the oil separator 30 is shortened, so that the pressure loss is reduced, Oil separation efficiency can be increased, and the overall size can be reduced. Further, the oil separator 30 can sufficiently separate the oil from the discharged refrigerant even if it is a CO ₂ refrigerant, and thus can improve the COP. Moreover, since oil can be sufficiently supplied to the refrigerant compressor 100, the reliability of the refrigerant compressor can be improved.

Although the refrigerant compressor 100 is a scroll type compressor, the refrigerant compressor 100 is not limited to this, and may be another type of refrigerant compressor such as a swash plate type compressor.

It is sectional drawing which shows the structure of the oil separator 30 in 1st Embodiment of this invention. 4 is a graph showing the relationship between L / φD and oil separation efficiency in the oil separator 30 by experimental data. 3 is a schematic diagram showing a configuration of a hot water storage type hot water supply apparatus having a refrigerant compressor provided with an oil separator 30. FIG. It is sectional drawing which shows the structure of the refrigerant compressor in 2nd Embodiment of this invention.

Explanation of symbols

30 ... Oil separator 31 ... Inflow pipe (inflow passage)
32 ... Inlet 33 ... Separation part 34a ... Bottom of chamber 34b ... Inner wall surface 35 ... Chamber 37, 85 ... Oil storage part 42 ... Inlet of discharge passage 43 ... Discharge passage 53 ... Sealed container (low pressure container)
57 ... Compression mechanism 93 ... Oil storage chamber 100 ... Refrigerant compressor 115 ... Heat pump cycle (refrigeration cycle)
145 ... Electric compressor (refrigerant compressor)

Claims (5)

A chamber (35) surrounded by an inner wall surface (34b) formed in a cylindrical shape, an inlet (32) opened to the inner wall surface (34b), and the inner wall surface (34b) connected to the inlet (32) ) Of the refrigerant flowing into the chamber (35) from the inlet (32) by the centrifugal force along the inner wall surface (34b). To separate the oil mixed in the refrigerant,
Further, a separation part (33) having a discharge passage (43) through which the remaining refrigerant separated from the oil is discharged, and an oil storage part (37, 85) connected to the chamber (35) and storing the separated oil. And an oil separator (30) provided in a refrigeration cycle (115) in which a refrigerant mainly composed of CO ₂ circulates,
A value (L / φD) obtained by dividing the distance L from the inlet (42) of the discharge passage to the bottom (34a) of the chamber by the inner diameter φD of the inner wall surface (34b) is 2.5 or more. Oil separator characterized by.   A refrigerant compressor comprising the oil separator (30) according to claim 1 integrally.   The refrigerant compressor according to claim 2, wherein a compression mechanism (57) is provided in a low-pressure vessel (53) that forms a low-pressure space therein.   The refrigerant compressor according to claim 3, wherein an oil storage section (85) in the oil separator (30) is integrally provided.   The refrigerant compressor according to any one of claims 2 to 4, wherein the refrigerant compressor is used in a heat pump cycle (115) for a water heater.

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