JP2014196855A - Oil separator and refrigeration cycle device outdoor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve oil separation efficiency by suppressing an oil separator from whirling up an oil reservoir, and solving such problems as poor lubrication of a compressor and degradation in heat transfer efficiency of a condenser and an evaporator.SOLUTION: An oil separator 12 separating oil from a refrigerant mixed with the oil comprises: a closed vessel 12a; an inlet tube 12c for introducing the refrigerant into the closed vessel 12a; a branch tube 12d branching a flow of the refrigerant flowing in the oil separator 12 via the inlet tube 12c, causing the refrigerant to flow into the closed vessel 12a from outlet ports Oand O, and generating a swirl flow in the closed vessel 12a; and an outlet tube 12b causing the refrigerant flowing out of the branch tube 12d into the closed vessel 12a to flow out of the closed vessel 12a. One end of the inlet tube 12c is connected to a hole on a side surface of the branch tube 12d, the refrigerant flowing out of the inlet tube 12c collides against a collision surface S in the branch tube 12, a direction of a segment L on the collision surface S extending along a tube axis Aof the branch tube 12d is inclined with respect to a direction of a tube axis Aof the inlet tube 12c.

Description

  The present invention relates to an oil separator that separates oil from a refrigerant mixed with oil, and an outdoor unit of a refrigeration cycle apparatus that includes the oil separator.

  In the refrigeration apparatus and the air conditioner, the lubricating oil for the compressor is gradually discharged from the compressor together with the refrigerant gas. As a result, when the lubricating oil is insufficient, poor lubrication of the compressor occurs. Further, when the lubricating oil reaches the condenser and the evaporator together with the refrigerant, heat transfer there is hindered.

  In order to prevent such a problem, an oil separator that separates the lubricating oil from the refrigerant gas mixed with the lubricating oil and returns the lubricating oil to the compressor is conventionally used. For example, Patent Document 1 discloses an oil separator intended to increase oil separation efficiency.

  FIG. 14 is a diagram showing a configuration of a conventional oil separator disclosed in Patent Document 1. As shown in FIG. The oil separator includes a shell 1, an inflow pipe 2, a discharge pipe 3, and an outflow pipe 4. The shell 1 includes a cylindrical portion and tapered portions above and below the cylindrical portion. The refrigerant gas mixed with the lubricating oil flows in from the inflow pipe 2 and swivels down in the shell 1 while colliding with the inner peripheral surface of the shell 1.

  At that time, the lubricating oil adheres to the inner peripheral surface of the shell 1 and is separated from the refrigerant gas (cyclone effect), and flows down toward the lower portion of the shell 1 by the action of gravity, thereby forming an oil reservoir in the lower portion of the shell 1. The lubricating oil is discharged from a discharge pipe 3 provided at the lower part of the shell 1 and returned to the compressor. On the other hand, the refrigerant gas from which the lubricating oil has been separated flows out from the outflow pipe 4 and is sent to a condenser or an evaporator.

  The end 4a of the outflow pipe 4 is disposed at a distance L1 downward from the center of the inflow pipe 2 and at a distance L2 upward from the lower opening 1a of the shell 1. Here, the distance L <b> 1 or the distance L <b> 2 is set to be five times or more the inner diameter of the inflow pipe 2. Thus, in this oil separator, separation of the lubricating oil and the refrigerant gas is promoted by sufficiently increasing the distance L1 or the distance L2.

JP 2002-61993 A

  However, in the prior art of Patent Document 1 described above, the refrigerant gas swirls and descends as it is in the shell 1 even after the lubricating oil is separated. Therefore, there exists a subject that refrigerant gas collides with the oil level of the oil sump formed in the lower part of the shell 1, and winds up the oil sump by the impact force.

  When the oil sump is wound up, the lubricating oil flows out from the outflow pipe 4, which causes problems such as poor lubrication of the compressor due to lack of lubricating oil and deterioration of heat transfer efficiency in the condenser and evaporator.

  The present invention solves the above-mentioned conventional problems, and improves oil separation efficiency by suppressing the winding of the oil reservoir of the oil separator, poor lubrication of the compressor, and heat transfer efficiency in the condenser and the evaporator. The purpose is to solve problems such as deterioration.

  An oil separator according to the present invention is an oil separator that separates oil from a refrigerant mixed with oil, and includes an airtight container, an inflow pipe that guides the refrigerant into the airtight container, and a refrigerant that flows in through the inflow pipe. Branching the flow, allowing the refrigerant to flow out from the first outlet and the second outlet into the sealed container, generating a swirling flow in the sealed container, and the refrigerant in the sealed container flowing out from the branch pipe An outflow pipe for flowing out of the sealed container, and one end of the inflow pipe is connected to a hole on a side surface of the branch pipe, and the refrigerant flowing out of the inflow pipe collides with a collision surface in the branch pipe, The direction of the line segment on the collision surface extending along the axis is inclined with respect to the pipe axis direction of the inflow pipe.

  Moreover, the outdoor unit of the refrigeration cycle apparatus according to the present invention employs a configuration in which the oil separator is provided.

  According to the present invention, the flow of the refrigerant is branched using the branch pipe, and the impact force when the refrigerant collides with the oil reservoir of the oil separator can be reduced, thereby suppressing the oil reservoir from being rolled up. As a result, oil separation efficiency is improved, and problems such as poor lubrication of the compressor and deterioration of heat transfer efficiency in the condenser or evaporator can be solved.

The figure which shows an example of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The perspective view which shows an example of a structure of the oil separator which concerns on Embodiment 1 of this invention. Cross section of the oil separator shown in FIG. The figure which shows an example of velocity vector distribution of a refrigerant gas flow Diagram showing an example of oil droplet trajectory line Cross section showing another model of oil separator The figure which shows another example of velocity vector distribution of a refrigerant gas flow The figure which shows an example of a structure of the oil separator which inclined the pipe-axis direction of the branch pipe with respect to the horizontal direction The figure which shows an example of a structure of the oil separator in case a branch pipe is a bending pipe Sectional drawing which shows an example of a structure of the oil separator which concerns on Embodiment 2 of this invention. Cross section of the oil separator shown in FIG. Sectional drawing which shows an example of a structure of the oil separator which concerns on Embodiment 3 of this invention. Sectional view of the oil separator shown in FIG. The figure which shows the structure of the conventional oil separator disclosed by patent document 1

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing an example of a refrigeration cycle apparatus 10 according to Embodiment 1 of the present invention. The refrigeration cycle apparatus 10 includes a compressor 11, an oil separator 12, a four-way valve 13, indoor heat exchangers 14a and 14b, an indoor expansion valve 15, an outdoor expansion valve 16, an outdoor heat exchanger 17, an accumulator 18, and a first on-off valve. 19, an oil return pipe 20, a second on-off valve 21, and a capillary 22 are provided. Each of these elements constitutes the refrigerant circuit 23. The refrigerant circuit 23 is filled with a refrigerant such as hydrofluorocarbon or hydrocarbon as a working fluid.

  The compressor 11 compresses a low-temperature and low-pressure refrigerant gas flowing out from an accumulator 18 described later, and converts it into a high-temperature and high-pressure refrigerant gas. The oil separator 12 separates the lubricating oil contained in the refrigerant gas discharged from the compressor 11.

  When the refrigeration cycle apparatus 10 is used for heating (hereinafter referred to as “heating”), the four-way valve 13 causes the refrigerant gas flowing out from the oil separator 12 to flow into the indoor heat exchangers 14a and 14b and The opening and closing of the valve is switched so that the refrigerant gas flowing out from the heat exchanger 17 flows into the accumulator 18.

  On the other hand, when the refrigeration cycle apparatus 10 is used for cooling (hereinafter referred to as “cooling”), the four-way valve 13 allows the refrigerant gas flowing out from the oil separator 12 to flow into the outdoor heat exchanger 17 and The opening and closing of the valve is switched so that the refrigerant gas flowing out of the heat exchangers 14 a and 14 b flows to the accumulator 18.

  The indoor heat exchangers 14 a and 14 b are heat exchangers provided in the indoor unit of the refrigeration cycle apparatus 10. The indoor heat exchangers 14a and 14b have, for example, a fin-and-tube structure. During heating, the high-temperature refrigerant gas that has flowed into the indoor heat exchangers 14a and 14b is condensed by being deprived of heat by the indoor air, and the refrigerant gas is liquefied. At the time of cooling, the low-temperature refrigerant liquid flowing into the indoor heat exchangers 14a and 14b takes heat from the indoor air and evaporates, and the refrigerant liquid is vaporized.

  The indoor expansion valve 15 depressurizes the refrigerant liquid flowing out of the outdoor heat exchanger 17 during cooling, and makes it easier for the refrigerant liquid to evaporate in the indoor heat exchangers 14a and 14b. The outdoor expansion valve 16 depressurizes the refrigerant liquid flowing out from the indoor heat exchangers 14a and 14b during heating, and makes it easier for the refrigerant liquid to evaporate in the outdoor heat exchanger 17.

  The outdoor heat exchanger 17 is a heat exchanger provided in the outdoor unit of the refrigeration cycle apparatus 10. The outdoor heat exchanger 17 has, for example, a fin-and-tube structure. During heating, the low-temperature refrigerant liquid flowing into the outdoor heat exchanger 17 takes the heat of the outside air and evaporates. The resulting refrigerant gas is discharged to the accumulator 18 at the saturation temperature or in a further heated state.

  During cooling, the high-temperature refrigerant gas flowing into the outdoor heat exchanger 17 releases heat to the outside air, and the refrigerant gas is liquefied. The resulting refrigerant liquid is discharged to the indoor heat exchangers 14 a and 14 b via the outdoor expansion valve 16 and the indoor expansion valve 15.

  The accumulator 18 separates refrigerant liquid or oil contained in the refrigerant gas and prevents liquid compression of the compressor 11. The first on-off valve 19 is an on-off valve for draining the liquid accumulated at the bottom of the accumulator 18.

  The oil return pipe 20 is used to return the lubricating oil separated by the oil separator 12 to the compressor 11. The second on-off valve 21 is an on-off valve for removing the lubricating oil accumulated at the bottom of the oil separator 12. The capillary 22 adjusts the flow rate of the lubricating oil when returning the lubricating oil to the compressor 11.

  In addition, when the refrigeration cycle apparatus 10 is used for hot water supply or hot water heating, the same cycle as the cycle during heating is repeated. However, the indoor heat exchangers 14a and 14b are replaced with, for example, a double-pipe heat exchanger that exchanges heat between the refrigerant and water.

  Next, the configuration of the oil separator 12 according to Embodiment 1 of the present invention will be described. FIG. 2 is a perspective view showing an example of the configuration of the oil separator 12 according to Embodiment 1 of the present invention.

  As shown in FIG. 2, the oil separator 12 includes a sealed container 12a, an outflow pipe 12b, an inflow pipe 12c, a branch pipe 12d, and a discharge pipe 12e. In FIG. 2, the illustration of the wall surface on the near side of the sealed container 12a is omitted so that the inside of the oil separator 12 can be seen.

  The sealed container 12a is a container sealed by welding hemispherical lids on the top and bottom of a cylindrical body. Although the lid is welded to the body here, the lid may be integrally formed with the body without welding.

The outflow pipe 12b is a pipe through which the refrigerant gas from which the lubricating oil is separated flows out of the sealed container 12a. Inlet of the outlet pipe 12b is provided below the outlet O ₂ of the branch pipe 12 to be described later. The inflow pipe 12c is a pipe that is provided through the side surface of the sealed container 12a and guides the refrigerant gas mixed with oil into the sealed container 12a.

In this embodiment, the inflow pipe 12c, the tube axis A ₁ is provided in the sealed container 12 so that the horizontal. Furthermore, the tip of the inflow pipe 12c is connected to the hole on the side surface of the branch pipe 12d in the sealed container 12a. Here, in the example of FIG. 2, the branch pipe 12d also its tube axis A ₂ is connected to the distal end of the inflow pipe 12c so as to be horizontal.

The branch pipe 12d branches the flow of the refrigerant gas flowing in through the inflow pipe 12c, and causes the refrigerant gas to flow out from the outlets O ₁ and O ₂ . The branch pipe 12d causes a swirling flow of the refrigerant gas in the sealed container 12a by causing the refrigerant gas to collide with the inner wall of the sealed container 12a from a substantially horizontal direction.

The refrigerant gas flowing out from the inflow pipe 12c collides with the collision surface S in the branch pipe 12d. Then, the direction of the line segment L on the impact surface S extending along the tube axis A ₂ of the branch pipe 12d is inclined with respect to the tube axis A ₁ of the inlet pipe 12c. This configuration is also shown enlarged in FIG.

Connecting branch pipe 12d In this way the inlet pipe 12c, the refrigerant gas is mixed with a large amount of the lubricating oil flows out from the outlet O ₁ of the branch pipe 12d, the refrigerant gas lubricant is almost separated, It flows out from the outlet O ₂ of the branch pipe 12d. The reason for this will be described in detail later.

Thereby, the flow of the refrigerant gas flowing out from the outlet O ₁ can be weakened. Further, since the lubricant gas flowing out from the outlet O ₂ is substantially separated from the lubricating oil, the refrigerant gas can be discharged out of the sealed container 12a from the outlet pipe 12b at an early stage with a small number of turns. Thereby, the impact at the time of refrigerant gas colliding with the oil sump in the bottom part of the airtight container 12a is relieved, and the oil sump is suppressed.

Incidentally, the direction of the line segment L on the impact surface S, if the angle between the tube axis A ₁ direction of the inlet pipe 12c is 90 degrees, the flow rate of the refrigerant gas flowing out from the outlet O _1, flow The ratio of the flow rate of the refrigerant gas flowing out from the outlet O ₂ is 1: 1. By adjusting the angle, the flow rate ratio of the refrigerant gas flowing out from the outlets O ₁ and O ₂ can be adjusted.

In the example of FIG. 2, as described above, the branch pipe 12d is provided to the tube axis A ₂ is horizontal. Thereby, a swirl flow can be efficiently generated in the sealed container 12a, and separation of the lubricating oil can be promoted.

  The discharge pipe 12e is provided through the bottom of the sealed container 12a, and discharges lubricating oil from the oil reservoir generated at the bottom of the sealed container 12a to the outside of the sealed container 12a. The discharged lubricating oil is returned to the compressor 11. Thereby, since only the separated lubricating oil can be selectively returned to the compressor 11, the performance and reliability of the compressor 11 can be ensured.

  FIG. 2 shows the dimensions of each part of the oil separator 12. This dimension is a dimension of a model of the oil separator 12 used in CFD (Computational Fluid Dynamics) described later.

  In this model, the inner diameter φ of the sealed container 12a is 67.2 mm, and the inner diameter φ of the outflow pipe 12b, the inflow pipe 12c, and the branch pipe 12d is 10.7 mm. The height of the sealed container 12a is 512.4 mm, and the distance from the upper end of the sealed container 12a to the lower end of the inflow pipe 12c having a length of 186 mm is 141 mm. Furthermore, the installation position of the inflow pipe 12c is 77.2 mm from the upper end of the sealed container 12a.

FIG. 3 is a cross-sectional view of the oil separator 12 shown in FIG. As can be seen from FIG. 3, the refrigerant gas flowing out from the inlet pipe 12c collides with the collision surface S of the branch pipe 12d in the tube axis A ₁ direction of the inlet pipe 12c. Then, the direction of the line segment L on the impact surface S along the tube axis A ₂ direction of the branch pipe 12d is inclined with respect to the tube axis A ₁ direction of the inlet pipe 12c. In the example of FIG. 3, the inclination angle α is 30 degrees.

  FIG. 3 also shows the dimensions of each part of the oil separator 12. This dimension is also the dimension of the model of the oil separator 12 used in the numerical fluid analysis described later, as in FIG.

That is, in this model, the tube axis _{A 1} of the inlet pipe 12c, is set to 13.7mm the distance between the center of the outlet pipe 12b. Further, the tube axis _{A 1} of the inlet pipe 12c, an intersection between the tube axis _{A 2} of the branch pipe 12d to is P, are the intersection P, and the distance between the center of the outlet pipe 12b and 19.4mm .

Further, the length of the branch pipe 12d is 40 mm, and the distances from the inner wall of the closed vessel 12a of the outlets O ₁ and O ₂ are both 7.9 mm. Further, as described above, the direction of the line segment L on the impact surface S of the branch pipe 12d is assumed to be inclined at an angle of 30 degrees with respect to the tube axis A ₁ direction of the inlet pipe 12c.

Connecting the inlet pipe 12c as described above and the branch pipe 12d, the refrigerant gas lubricant is substantially separated to flow from the outlet O ₂ of the branch pipe 12d. Next, this phenomenon will be described in detail.

Refrigerant gas lubricant is mixed, the pressure loss gradient during flowing from the inflow pipe 12c and to the outlet O ₂ side of the branch pipe 12d, the refrigerant gas lubricant is mixed, the inlet pipe 12c of the branch pipe 12d It becomes larger than the pressure loss gradient when flowing into the outlet O ₁ side. Here, the “pressure loss gradient” means a pressure gradient based on the pressure loss.

  In general, when a gas-liquid two-phase flow containing a gas-phase fluid and a liquid-phase fluid branches in two directions having different pressure-loss gradients, the gas-phase fluid and the gas-phase fluid flow toward the side with the larger pressure-loss gradient. It can be said that the phase fluid is likely to flow in.

  This is because the pressure loss of the gas phase fluid is larger than the pressure loss of the liquid phase fluid, assuming the same flow path and the same flow rate. When the pressure loss gradient is different in bi-directional branching, in order to maintain the pressure loss balance in each direction, a large amount of gas phase fluid flows on the side where the pressure loss gradient is large and the liquid phase fluid is on the side where the pressure loss gradient is small Will flow in a lot.

  Regarding such a phenomenon, Asano et al. Conducted a diversion experiment of an air-water-gas-liquid two-phase flow using a plurality of Y-shaped branch pipes having different branch angles, and reported the results (Y-shaped branch). Study on Phase Separation Characteristics of Gas-Liquid Two-Phase Flow with a Tube (1st Report), Transactions of the Japan Society of Mechanical Engineers (B), Vol. 67, No. 654, 350-355).

  In this diversion experiment, Asano et al. Confirmed that the phase separation performance improved as θ was decreased within the range of the branching angle θ (corresponding to the inclination angle α in FIG. 3) = 30 to 90 degrees. Yes. This result is consistent with the fact that the smaller the branch angle θ of the Y-shaped branch pipe, the easier the liquid phase having a large inertial force goes straight. Further, there is a tendency that a large amount of gas phase fluid flows on the side where the pressure loss gradient is large, and a large amount of liquid phase fluid flows on the side where the pressure loss gradient is small.

Further, since an inertial force larger than the inertial force acting on the gas-phase refrigerant gas acts on the liquid-phase lubricating oil, the lubricating oil flows from the outlet O ₁ more than the outlet O ₂ of the branch pipe 12d. It can be said that it is easy to leak.

Thus, by using the branch pipe 12d, it is possible to more outflow of lubricant oil from the outlet O ₁ of the branch pipe 12d, from the outlet O ₂ is possible to flow out the refrigerant gas advanced separation of lubricating oil it can.

  FIG. 4 is a diagram illustrating an example of a velocity vector distribution of the refrigerant gas flow. This distribution is calculated by numerical fluid analysis using the model of the oil separator 12 whose dimensions are shown in FIGS.

In the refrigeration cycle apparatus 10 as shown in FIG. 1, when an operation equivalent to 16 horsepower is performed, the pressure of the refrigerant gas flowing into the oil separator 12 is 3.0 MPa and the temperature is Celsius based on the result of the actual machine test. 88.5 degrees, the flow rate is considered to be about 3.1 × 10 ⁻³ m ³ / s. Therefore, such a condition is given as an analysis condition at the inlet of the inflow pipe 12c. Further, 0 MPa was set as the analysis condition at the outlet of the outflow pipe 12b.

Furthermore, R410A was adopted as the refrigerant, and the physical property value of R410A was used in the numerical fluid analysis. Specifically, a density of 90.6 kg / m ³ , a constant pressure specific heat of 1.232 kJ / kgK, and a viscosity coefficient of 17.0 μkg / m-s were used.

Further, PVE (Polyvinyl Ether) oil is adopted as the lubricating oil, and the physical property values of the PVE oil are used in the numerical fluid analysis. Specifically, a value of 936.9 kg / m ³ was used as the density. The discharge amount of the lubricating oil was 9.2 × 10 ⁻⁴ kg / s.

From FIG. 4, it can be seen that the refrigerant gas flows out not only from the outlet O ₁ of the branch pipe 12 d but also from the outlet O ₂ . According to the analysis result, the flow rate of the refrigerant gas flowing out from the outlet O ₁ is about 2.8 × 10 ⁻³ m ³ / s, and the flow rate of the refrigerant gas flowing out from the outlet O ₂ is about 0.3 ×. 10 ⁻³ m ³ / s. That is, the flow rate of the refrigerant gas flowing out from the outlet O _1, the flow rate ratio of the refrigerant gas flowing out from the outlet O ₂ 9: 1.

Further, in the example of FIG. 4, the presence of the inlet pipe 12c, and the swirling flow of the refrigerant gas flowing out from the outlet O _1, and the swirling flow of the refrigerant gas flowing out from the outlet O ₂ does not conflict between the swirling flow Interference is suppressed. Therefore, the lubricating oil is smoothly separated from the refrigerant gas by the centrifugal force.

Furthermore, the DPM (Discrete Phase Model) analysis determines the ratio of the lubricating oil mixed in the refrigerant gas in the form of oil droplets from the outlet O ₁ and outlet O _{2 of} the branch pipe 12d. confirmed.

The oil droplets having a diameter exceeding 10 μm are largely out of the outlet O ₂ and are out of the outlet O ₁ because the influence of inertia force is large. Therefore, in the DPM analysis, the trajectory of an oil droplet having a diameter of 5 μm carried by mixing with the refrigerant gas from the inflow pipe 12b was traced. Oil droplets of this size are considered to flow along the flow of the refrigerant gas because the influence of inertia force is weak.

FIG. 5 is a diagram illustrating an example of a trajectory line of oil droplets. As a result of DPM analysis, when the number of oil droplets flowing out from the outlet O ₁ and the number of oil droplets flowing out from the outlet O ₂ were measured, the ratio of the numbers was 9: 1.

Thus, it can be seen that even oil droplets having a diameter of 5 μm almost flow out from the outlet O ₁ and hardly flow out from the outlet O ₂ . This result almost coincides with the result observed by the experiment. Therefore, by generating the swirling flow in the refrigerant gas flowing out from the outlet O _2, it can be easily removed oil droplets from the refrigerant gas.

  FIG. 6 is a cross-sectional view showing another model of the oil separator 12. The difference from the model shown in FIG. 3 is that the inclination angle α is 45 degrees. In this model, the outflow pipe 12b is bent in the sealed container 12a.

That is, in this model, although the inlet part of the outflow pipe 12b in the sealed container 12a is at the center of the sealed container 12a as in the model of FIG. 3, the outlet part 12b _out from which the outflow pipe 12b exits from the sealed container 12a is 3 is different from the model shown in FIG. 3 in a position shifted from the center of the sealed container 12a. In the cross-sectional view of FIG. 6, the position of the outlet portion 12b _out is shown for reference.

Specifically, in this model, the tube axis A ₁ of the inlet pipe 12c, is set to 9.7mm distance between the center of the inlet portion of the outlet pipe 12b. The distance between the center of the inlet portion of the intersection between the tube axis A ₁ of the inlet pipe 12c to the tube axis A ₂ of the branch pipe 12d and the intersection point P in the case of a P outlet pipe 12b, the length of the branch pipe 12d, and the distance from the inner wall of the sealed container 12a of the outlet _O 1, _{O 2} is the same as in FIG.

  The result of the numerical fluid analysis similar to that shown in FIG. 4 using the model of the oil separator 12 whose dimensions are shown in FIG. 6 is shown below. FIG. 7 is a diagram illustrating another example of the velocity vector distribution of the refrigerant gas flow. Analysis conditions in the numerical analysis of FIG. 7 are the same as those of FIG.

Also in FIG. 7, it can be seen that the refrigerant gas flows out not only from the outlet O ₁ of the branch pipe 12 d but also from the outlet O ₂ . According to the analysis result, the flow rate of the refrigerant gas flowing out from the outlet O ₁ is about 2.6 × 10 ⁻³ m ³ / s, and the flow rate of the refrigerant gas flowing out from the outlet O ₂ is about 0.5 ×. 10 ⁻³ m ³ / s. That is, the ratio of the flow rate of the refrigerant gas flowing out from the outlet O ₁ and the flow rate of the refrigerant gas flowing out from the outlet O ₂ is 8: 2.

Further, in the model of FIG. 6, as in the case shown in FIG. 5, when the trajectory of the oil droplet having a diameter of 5 μm was traced by DPM analysis, most of the oil droplet having a diameter of 5 μm did not flow out from the outlet O ₂ . It was found that the gas flowed out from the outlet O ₁ .

Thus, according to this embodiment, by using a branch pipe 12d branches the flow of the refrigerant gas, it is possible to weaken the flow of the refrigerant gas flowing out from the outlet O _1. Further, since the lubricant gas flowing out from the outlet O ₂ is substantially separated from the lubricating oil, the refrigerant gas can be discharged out of the sealed container 12a from the outlet pipe 12b at an early stage with a small number of turns.

  Thereby, the impact at the time of refrigerant gas colliding with the oil sump in the bottom part of the airtight container 12a is relieved, and the oil sump is suppressed. As a result, oil separation efficiency is improved, and problems such as poor lubrication of the compressor and deterioration of heat transfer efficiency in the condenser and evaporator are eliminated.

  4 and 7, the case where the inclination angles α shown in FIGS. 3 and 6 are 30 degrees and 45 degrees, respectively, has been described. However, the present invention is not limited to these, and the inclination angle α is an acute angle, that is, from 0 degrees. If it is large and less than 90 degrees, the above effects can be obtained.

In the above embodiment, the direction of the tube axis A ₂ of the branch pipe 12d is set to the horizontal direction, it is also possible to tilt the direction of the tube axis A ₂ with respect to the horizontal direction.

Figure 8 is a diagram showing an example of the configuration of the oil separator 12 which is inclined in the direction of tube axis A ₂ of the branch pipe 12d with respect to the horizontal direction. In this case, as described above, from the outlet O ₁ of the branch pipe 12d, the refrigerant gas lubricant are mixed many flows, the refrigerant gas lubricant is substantially separated flows out from the outlet O _2.

For this reason, in this configuration, the outlet O ₁ is directed upward from the horizontal direction so that the refrigerant gas flows out upward from the horizontal from the outlet O ₁ . Accordingly, the refrigerant gas flowing out from the outlet O ₁ is time to pivot in a sealed container 12a can be lengthened, and it becomes possible to sufficiently separate the lubricating oil from the refrigerant gas.

Here, since the flow of the refrigerant gas flowing out from the outlet O ₁ is fast, the upward flow of the refrigerant gas is formed near the inner wall surface of the sealed container 12a as shown in FIG. At that time, the refrigerant gas flowing out from the outlet O ₁ swirls, and the lubricating oil collides with and adheres to the inner wall surface of the sealed container 12a. As a result, the lubricating oil is separated from the refrigerant gas. The separated lubricating oil gradually moves below the sealed container 12a due to the influence of gravity to form an oil reservoir.

On the other hand, the refrigerant gas that has reached the upper part of the sealed container 12a while turning forms a downward flow in the central portion of the sealed container 12a. Therefore, there is little interference with the flow of the refrigerant gas flowing out from the outlets O ₁ and O ₂ , and the swirling flow of the refrigerant gas is not greatly affected.

  Further, as shown in FIG. 8, the refrigerant gas descending from the upper part of the sealed container 12a forms a swirling flow even in the lower part of the branch pipe 12d. Thereby, the lubricating oil mixed with the refrigerant gas collides and adheres to the inner wall surface of the sealed container 12a and is separated from the refrigerant gas. Thereafter, the refrigerant gas from which the lubricating oil has been separated forms an upward flow in the central portion of the sealed container 12a. Then, the refrigerant gas flows out from the outflow pipe 12b.

The refrigerant gas flowing out from the outlet O ₂ of the branch pipe 12d, by the action of the branch pipe 12d, it is progressing separation of the lubricating oil. Therefore, this refrigerant gas flows out from the outflow pipe 12b early while separating the slightly mixed lubricating oil by swirling.

Thus, by making the outflow of the refrigerant gas from the outlet O ₁ upward from the horizontal direction, the number of times the refrigerant gas swirling with a large amount of lubricating oil can be increased, and the oil separation performance is improved. Can be achieved.

  2 to 8, the branch pipe 12d is assumed to be a straight pipe. By making the branch pipe 12d a straight pipe, the shape thereof can be simplified, so that there is an advantage that a quality error at the time of mass production is reduced and a desired effect can be stably obtained. However, the shape of the branch pipe 12d is not limited to this, and may be, for example, a bent pipe having a bent portion.

FIG. 9 is a diagram showing an example of the configuration of the oil separator 12 when the branch pipe 12d is a bent pipe. As shown in FIG. 9, the refrigerant gas flowing out from the inflow pipe 12c collides with the collision surface S in the branch pipe 12d. Then, the direction of the line segment L on the impact surface S extending along the tube axis A ₂ of the branch pipe 12d is inclined with respect to the tube axis A ₁ of the inlet pipe 12c.

Here, in the example of FIG. 9, the outlet O ₂ of the branch pipe 12 d is provided more on the inner peripheral side than the outlet O ₁ in the circular cross section of the sealed container 12 a. With such a configuration, the swirling flow of the refrigerant gas that flows out from the outlet O ₁ and contains a large amount of lubricating oil, and the refrigerant gas that flows out of the outlet O _{2 and} from which the lubricating oil is substantially separated. Interference with the swirling flow can be suppressed.

Or simply flow out, the length from the connection portion between the inflow pipe 12c to the outlet O _2, by less than the length from the connection portion to the outlet O _1, from both the outlet O _1, O ₂ The interference between the swirling flows of the refrigerant gas may be suppressed.

In the above embodiment, the inner diameter of the branch pipe 12d is, the case has been described where is constant along the direction of the tube axis A ₂ of the branch pipe 12d, the inner diameter varies along the direction of the tube axis A ₂ It is good to do. For example, the inner wall surface of the branch pipe 12d may be tapered.

(Embodiment 2)
In the first embodiment, the inflow pipe 12c is provided in the horizontal direction, but the inflow pipe 12c may be provided in the vertical direction. In the present embodiment, a case where the inflow pipe 12c is provided in the vertical direction will be described.

  FIG. 10 is a cross-sectional view showing an example of the configuration of the oil separator 12 according to Embodiment 2 of the present invention. The oil separator 12 includes an airtight container 12a, an outflow pipe 12b, an inflow pipe 12c, a branch pipe 12d, a discharge pipe 12e, and an oil trap 12f.

  As shown in FIG. 11, which will be described later, the outflow pipe 12b is provided at the upper center of the sealed container 12a. The cross-sectional view of FIG. 10 is a view when the sealed container 12a is cut along a vertical plane passing through the center. FIG. 10 shows a state where the inflow pipe 12c is provided on the other side of the outflow pipe 12b. Further, the shape of the inside (inner wall surface) of the inflow pipe 12c and the branch pipe 12d is also shown.

  The sealed container 12a, the outflow pipe 12b, and the discharge pipe 12e shown in FIG. 10 are the same as the closed container 12a, the outflow pipe 12b, and the discharge pipe 12e shown in FIG. Also, the inflow pipe 12c is provided in the vertical direction, unlike the case of FIG.

Also in the case of FIG. 10, the refrigerant gas flowing out from the inflow pipe 12c collides with the collision surface S in the branch pipe 12d. Then, the direction of the line segment L on the impact surface S extending along the tube axis A ₂ of the branch pipe 12d is inclined with respect to the tube axis A ₁ of the inlet pipe 12c.

By using such a branch pipe 12d, the refrigerant gas is mixed with a large amount of the lubricating oil flows out from the outlet O ₁ of the branch pipe 12d, the refrigerant gas lubricant is almost separated, the branch pipe 12d It made to flow out from the outlet O _2.

Thereby, the flow of the refrigerant gas flowing out from the outlet O ₁ can be weakened. Further, since the lubricant gas flowing out from the outlet O ₂ is substantially separated from the lubricating oil, the refrigerant gas can be discharged out of the sealed container 12a from the outlet pipe 12b at an early stage with a small number of turns. Thereby, the impact at the time of refrigerant gas colliding with the oil sump in the bottom part of the airtight container 12a is relieved, and the oil sump is suppressed.

In particular, in the configuration shown in FIG. 10, the outlet O ₂ of the branch pipe 12 d is directed upward from the horizontal direction, and the refrigerant gas flows out from the outlet O ₂ upward from the horizontal. The inlet of the outlet pipe 12b is provided at an upper portion of the outlet O ₂ of the branch pipe 12d. Thereby, before the refrigerant gas from which the lubricating oil is separated is mixed with the lubricating oil again, the refrigerant gas can be flowed out of the sealed container 12a.

In addition, the refrigerant gas flows downward at the outlet O ₁ of the branch pipe 12d, whereas the refrigerant gas flows upward at the outlet O ₂ . Therefore, it is possible to prevent the swirling flow caused by the refrigerant gas flowing out from the outlet O ₁ and the swirling flow caused by the refrigerant gas flowing out from the outlet O ₂ from colliding and weakening the momentum of the swirling flow.

  Returning to the description of FIG. 10, the oil capturing unit 12 f captures mist-like lubricating oil having a fine particle diameter from the refrigerant gas mixed with the lubricating oil, and allows the refrigerant gas from which the lubricating oil is separated to pass therethrough. The oil capturing part 12f is configured by, for example, a metal mesh. Here, the oil capturing part 12f is provided away from the inflow port of the outflow pipe 12b, but may be attached to the inflow port of the outflow pipe 12b.

  Thereby, since the lubricating oil that could not be separated is separated from the refrigerant gas, the refrigerant gas mixed with the lubricating oil can be prevented from flowing out from the outflow pipe 12b as it is, and the oil separation efficiency can be further improved. it can.

  FIG. 11 is a cross-sectional view of the oil separator 12 shown in FIG. As shown in FIG. 11, the inflow pipe 12c and the branch pipe 12d are provided at positions shifted from the center of the circular cross section of the sealed container 12a.

With such a configuration, a swirling flow of the refrigerant gas flowing out from the outlets O ₁ and O ₂ of the branch pipe 12d is generated, and the refrigerant gas collides with the sealed container 12a, thereby being mixed with the refrigerant gas. The lubricating oil that is present is separated from the refrigerant gas.

(Embodiment 3)
In the first and second embodiments, a space that flows refrigerant from the outlet O ₁ of the branch pipe 12d, while the outlet O ₂ and space in which the refrigerant flows out is in communication, so as to partition these spaces May be. In the present embodiment, a case where a partition portion that partitions both the spaces is provided will be described.

  FIG. 12 is a cross-sectional view showing an example of the configuration of the oil separator 12 according to Embodiment 3 of the present invention. The oil separator 12 includes a sealed container 12a, an outflow pipe 12b, an inflow pipe 12c, a branch pipe 12d, a discharge pipe 12e, an oil catching part 12f, and a partitioning part 12g.

  As will be described later with reference to FIG. 13, the inflow pipe 12c and the branch pipe 12d are provided on the back side of the outflow pipe 12b. In addition, in FIG. 12, about the inflow pipe 12c and the branch pipe 12d, the shape of the inside (inner wall surface) is also shown.

  The sealed container 12a, the outflow pipe 12b, the inflow pipe 12c, the branch pipe 12d, the discharge pipe 12e, and the oil trap 12f shown in FIG. 12 are the same as the sealed container 12a, the outflow pipe 12b, the inflow pipe 12c, and the branch pipe 12d shown in FIG. The exhaust pipe 12e and the oil capturing part 12f are the same.

Partition unit 12g, a space where refrigerant flows out from the outlet O ₁ of the branch pipe 12d, the refrigerant from the outlet O ₂ is a plate-like member separates the space for the outflow. The partition 12g extends in the vertical direction of the sealed container 12a. In addition, the space on both sides of the partition 12g between the upper part (between the upper end of the partition 12g and the lid of the sealed container 12a) and the lower part (between the lower end of the partition 12g and the bottom of the sealed container 12a) of the sealed container 12a. Communicate.

As described above, from the outlet O ₁ of the branch pipe 12d refrigerant gas mixed with lubricating oil flows out, refrigerant gas lubricant is substantially separated flows out from the outlet O _2. By providing the partitioning portion 12g in such a case, the refrigerant gas flowing out from the outlet O ₁ of the branch pipe 12d, and the refrigerant gas flowing out from the outlet O ₂ that is commingled is suppressed. As a result, the refrigerant gas flowing out from the outlet O ₂ flows out from the outflow pipe 12b without being mixed with the lubricating oil again, so that the oil separation efficiency can be improved.

Further, a gap at the top of the sealed container 12a, by communicating the both sides of the space of the partition part 12g, the refrigerant gas flowing out from the outlet O ₂ of the branch pipe 12d, to be smoothly flow out from the outlet pipe 12b it can. Furthermore, by providing a gap in the lower part of the sealed container 12a and communicating the spaces on both sides of the partition portion 12g, the oil separated in both spaces can be smoothly discharged from the single discharge pipe 12e.

  In the example of FIG. 12, the space is communicated by making a gap above and below the partition 12g, but the upper and lower portions of the partition 12g provided without a gap from the upper end to the lower end of the sealed container 12a. It is good also as providing a communicating hole and making space communicate.

  FIG. 13 is a cross-sectional view of the oil separator 12 shown in FIG. As shown in FIG. 13, the inflow pipe 12c and the branch pipe 12d are provided at positions shifted from the center of the circular cross section of the sealed container 12a.

With such a configuration, a swirling flow of the refrigerant gas flowing out from the outlets O ₁ and O ₂ of the branch pipe 12d is generated, and the refrigerant gas collides with the sealed container 12a, thereby being mixed with the refrigerant gas. The lubricating oil that is present is separated from the refrigerant gas.

  12 and 13 show the case where the inflow pipe 12c is provided in the vertical direction, the partition portion 12g may be provided similarly when the inflow pipe 12c is provided in the horizontal direction.

  The oil separator according to the present invention is suitable for use in devices such as an air conditioner, a water heater, and a hot water heater.

DESCRIPTION OF SYMBOLS 1 Shell 1a Shell lower opening part 2 Inflow pipe 3 Outlet pipe 4 Outflow pipe 4a End part of outflow pipe 10 Refrigeration cycle apparatus 11 Compressor 12 Oil separator 12a Sealed container 12b Outflow pipe 12c Inflow pipe 12d Branch pipe 12e Exhaust pipe 12f Oil capture part 12g Partition part 13 Four-way valve 14a, 14b Indoor heat exchanger 15 Indoor expansion valve 16 Outdoor expansion valve 17 Outdoor heat exchanger 18 Accumulator 19 First on-off valve 20 Oil return pipe 21 Second on-off valve 22 Capillary 23 Refrigerant circuit

Claims (8)

An oil separator for separating the oil from the refrigerant mixed with the oil,
A sealed container;
An inflow pipe for guiding the refrigerant into the sealed container;
A branch pipe that branches the flow of the refrigerant flowing in via the inflow pipe, causes the refrigerant to flow into the sealed container from the first outlet and the second outlet, and generates a swirling flow in the sealed container; ,
An outflow pipe that causes the refrigerant in the sealed container that has flowed out of the branch pipe to flow out of the sealed container, and
One end of the inflow pipe is connected to a hole in a side surface of the branch pipe, and the refrigerant flowing out of the inflow pipe collides with a collision surface in the branch pipe and extends along the tube axis of the branch pipe The direction of the upper line segment is an oil separator inclined with respect to the tube axis direction of the inflow pipe.   The oil separator according to claim 1, wherein the branch pipe is a straight pipe and branches the flow of the refrigerant in directions opposite to each other.   The second outlet is on the side of the branch pipe on the side where the tube axis direction of the inlet pipe and the direction of the line segment on the collision surface form an acute angle, and the second outlet is the refrigerant. 3. The oil separator according to claim 1, wherein the oil separator is made to flow downward from a horizontal plane, and an inlet of the outlet pipe is provided at a lower portion of the second outlet.   The second outlet is on the side of the branch pipe on the side where the tube axis direction of the inlet pipe and the direction of the line segment on the collision surface form an acute angle, and the second outlet is the refrigerant. 3. The oil separator according to claim 1, wherein the oil separator is made to flow upward from a horizontal plane, and an inlet of the outlet pipe is provided at an upper portion of the second outlet.   A partition that partitions a space from which the refrigerant flows out from the first outlet and a space from which the refrigerant flows out from the second outlet; the partition extends in a vertical direction; The oil separator according to any one of claims 1 to 4, wherein spaces on both sides of the partition portion communicate with each other between an upper portion and a lower portion.   The oil according to any one of claims 1 to 5, further comprising an oil capturing portion that captures the oil and allows the refrigerant to pass between the second outflow port and the inflow port of the outflow pipe. Separator.   The oil separator according to any one of claims 1 to 6, further comprising a discharge pipe for discharging oil separated from the refrigerant to the outside of the closed container at a bottom portion of the closed container.   An outdoor unit of a refrigeration cycle apparatus comprising the oil separator according to any one of claims 1 to 7.

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