JP6782517B2 - Oil separator - Google Patents

Description

The present invention relates to an oil separator for separating lubricating oil from a mixed fluid of refrigerant gas and lubricating oil discharged from a screw compressor of a heat pump.

In the heat pump, the required heating or cooling (freezing) work is performed by circulating the closed circuit while changing the state of the refrigerant compressed by the screw compressor through the condenser, the expansion valve and the evaporator. When ammonia (NH ₃ ) is used as the refrigerant in such a heat pump, insoluble oil is generally used as the lubricating oil supplied to the screw compressor, and this insoluble oil is used in the condenser or evaporator. When it flows into a heat exchanger such as the above, this insoluble oil adheres to the heat transfer surface to lower the heat transfer performance, resulting in a problem that the heat exchange efficiency in the heat exchanger is lowered.

Therefore, an oil separator for separating the lubricating oil from the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor is generally provided between the screw compressor and the condenser of the refrigerant circulation circuit. ing. In particular, when insoluble oil is used as a lubricant, a high-performance oil separator is required.

By the way, as an oil separator, Patent Document 1 proposes a combination of a gravity settling method and a demister method, and Patent Document 2 proposes an oil separator using a demista, a corelesser, and a discharge deflector. ing. Further, Patent Document 3 proposes an oil separator using a centrifugal separation means as an oil separation means.

Here, as an example of the conventional oil separator, the one using the gravity settling method and the corelesser is shown in FIG.

That is, FIG. 7 is a side sectional view showing an example of a conventional oil separator, and the illustrated oil separator 101 includes a horizontally placed cylindrical container-shaped shell 102, and the inside of the shell 102 is It is divided into a first branch chamber S1 and a second branch chamber S2 by a partition wall 103.

The first branch chamber S1 of the shell 102 is provided with a vertical wall 104 erected vertically from the bottom, and a gas inlet 105 opens at the upper part of the first branch chamber S1 to form the first branch chamber S1. An oil outlet 106 is open at the bottom. The gas inlet 105 is connected to the discharge side of the screw compressor (not shown) via the refrigerant pipe 107, and the oil outlet 106 is connected to the inside of the screw compressor via the oil pipe 108.

Further, the corelesser 109 is housed in the second branch chamber S2 of the shell 102 in a horizontal state, and one end in the longitudinal direction (the left end in FIG. 7) is attached to the partition wall 103. The corelesser 109 is a member formed in a cylindrical shape including a microglass fiber, and the inside thereof communicates with the first branch chamber S1 via a circular hole-shaped communication hole 103a formed in the partition wall 103. There is.

A gas outlet 110 is opened at the upper part of the second branch chamber S2 of the shell 102, and an oil return port 111 is opened at the bottom of the second branch chamber S2. The gas outlet 110 is connected to a condenser (not shown) via a refrigerant pipe 112, and the oil return port 111 is connected to the suction side of the screw compressor via the oil pipe 113.

In the oil separator 101 configured as described above, the first branch chamber from the gas inlet 105 in which the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor (not shown) to the refrigerant pipe 107 opens in the shell 102. When flowing into S1, this mixed fluid flows through the first branch chamber S1 toward the end plate 102a to the left in FIG. 7, collides with the end plate 102a and reverses the flow direction, and moves the first branch chamber S1 to the right in FIG. Although it flows at a low speed toward the direction, in this process, the lubricating oil having a specific gravity larger than that of the refrigerant gas is separated from the gas refrigerant by gravity and settles, and the lubricating oil is accumulated at the bottom of the first branch chamber S1.

After that, when the mixed fluid containing a small amount of lubricating oil flows into the inside of the corelesser 109 arranged in the second branch chamber S2 from the communication hole 103a of the partition wall 103, the small amount of lubricating oil contained in this mixed fluid is separated by the corelesser 109. It collects at the bottom of the second branch room S2. Then, the refrigerant gas from which the lubricating oil has been almost completely separated and removed is discharged from the corelesser 109 and introduced into a condenser and an evaporator (not shown) from the gas outlet 110 opened in the shell 102 through the refrigerant pipe 112. .. Therefore, the lubricating oil hardly flows into the condenser and the evaporator, and the deterioration of the heat exchange efficiency between the condenser and the evaporator due to the adhesion of the lubricating oil to the heat transfer surface can be prevented.

Further, the lubricating oil accumulated in the bottom of the first branch chamber S1 of the shell 102 was supplied from the oil outlet 106 through the oil pipe 108 to the bearing portion in the screw compressor (not shown), and accumulated in the bottom of the second branch chamber S2. The lubricating oil is returned from the oil return port 111 through the oil pipe 113 to the screw compressor together with the refrigerant gas, and is used for lubricating and cooling the screw compressor.

Jikkai Sho 54-138152 Japanese Unexamined Patent Publication No. 1-2698887 Japanese Unexamined Patent Publication No. 8-309128

However, the oil separators proposed in Patent Documents 1 to 3 have a problem that they are larger than other components of the heat pump, and their transportation costs and material costs are high. For example, in the conventional oil separator 101 shown in FIG. 7, the region where the lubricating oil is separated by the gravity settling motion and the region where the lubricating oil is separated by the corelesser 109 do not overlap each other and are independent along the longitudinal direction. Since the setting is set to, the total length L'of the oil separator 101 becomes long, and the oil separator 101 becomes large.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an oil separator capable of miniaturization while maintaining high oil separation performance.

In order to achieve the above object, the oil separator according to claim 1 is for separating the lubricating oil from the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor of the heat pump.
It is provided with a horizontally placed closed container-shaped outer cylinder shell and a bottomed cylindrical inner cylinder shell inserted into the outer cylinder shell from one end in the longitudinal direction of the outer cylinder shell.
At one end in the longitudinal direction of the outer cylinder shell, a gas inlet is opened in the tangential direction with respect to the annular space between the outer cylinder shell and the inner cylinder shell, and protrudes from the outer cylinder shell of the inner cylinder shell. Open a gas outlet at one end in the longitudinal direction of the part
An oil outlet is opened at the bottom of the outer cylinder shell, and an oil return port is opened at the bottom of a portion of the inner cylinder shell that protrudes from the outer cylinder shell.
It is characterized in that a corelesser is housed and arranged inside the inner cylinder shell.

The invention according to claim 2 is the invention according to claim 1, wherein a plurality of ring-shaped inner rings and outer rings are provided at axial intervals on the inner circumference of the outer cylinder shell and the outer circumference of the inner cylinder shell. It is characterized by being arranged.

The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, a demister is housed and arranged on the upstream side of the corelesser in the flow direction of the mixed fluid inside the inner cylinder shell. ..

The invention according to claim 4 is the invention according to any one of claims 1 to 3.
A wave stop plate is arranged at the bottom of the outer cylinder shell near the gas inlet, and the oil outlet is opened on the other end side in the longitudinal direction away from the gas inlet of the outer cylinder shell. ..

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the gas outlet is opened on the downstream side of the downstream end surface of the corelesser in the flow direction of the mixed fluid. It is characterized by.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the oil outlet is connected to a bearing portion inside the screw compressor via an oil cooler, and the oil return port is opened. It is characterized in that it is directly connected to the suction side of the screw compressor.

According to the first aspect of the present invention, the lubricating oil is separated from the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor through the following first to third steps.

That is, in the first step, the mixed fluid discharged from the screw compressor flows tangentially into the annular space between the outer cylinder shell and the inner cylinder shell from the gas inlet of the oil separator and turns (cyclone motion). Therefore, the lubricating oil having a specific gravity larger than that of the refrigerant gas flows along the inner surface of the outer cylinder shell by centrifugal force. Here, the lubricating oil having a high viscosity drops because its flow velocity decreases due to the frictional resistance on the inner surface of the outer cylinder shell, and the lubricating oil collects at the bottom of the outer cylinder shell, so that the lubricating oil is separated from the refrigerant gas. Lubricant.

In the second step, the lubricating oil that was not separated in the first step moves horizontally in the annular space along with the refrigerant gas, but in the process, the lubricating oil having a higher specific gravity than the refrigerant gas becomes the refrigerant gas due to gravity. The lubricating oil separated from and settled from the refrigerant gas increased in particle size due to collision with the end face (end plate) of the outer cylinder shell and reversal of the flow direction, and separated from the refrigerant gas by the second gravity settling. Lubricating oil is separated from the refrigerant gas because the lubricating oil collects on the bottom of the outer cylinder shell.

In the third step, the mixed fluid passes through the corelesser to separate the fine particles of the lubricating oil that were not separated in the second step.

As described above, since the lubricating oil contained in the mixed fluid is separated through the first to third steps, the oil separation performance of the oil separator is improved.

Further, since the region where the lubricating oil is separated by the gravity settling motion in the first and second steps and the region where the lubricating oil is separated by the corelesser in the third step are arranged so as to overlap in the longitudinal direction, the total length of the oil separator is shortened. Therefore, the miniaturization of the oil separator can be realized.

As a result, it is possible to reduce the size of the oil separator while maintaining high oil separation performance in the oil separator.

According to the invention of claim 2, the mixed fluid discharged from the screw compressor flows tangentially into the annular space between the outer cylinder shell and the inner cylinder shell from the gas inlet of the oil separator and swirls ( As a result of the cyclone movement), the lubricating oil flows along the inner surface of the outer cylinder shell due to centrifugal force, but the flow of the lubricating oil is blocked by the multiple inner rings arranged on the inner circumference of the outer cylinder shell, so that the inner cylinder shell Fall towards. Then, the lubricating oil that has fallen on the inner cylinder shell flows along the outer surface of the inner cylinder shell along the flow of the mixed fluid, and the flow of the lubricating oil is caused by a plurality of outer rings arranged on the outer circumference of the inner cylinder shell. Since it is dammed, the lubricating oil falls and falls to the bottom inside the outer cylinder shell and is stored. As a result, the lubricating oil is effectively separated from the mixed fluid.

According to the invention of claim 3, the lubricating oil not separated in the second step is first separated from the refrigerant gas by inertial collision in the demister and then separated by the corelesser. Therefore, the lubricating oil in the third step is separated. Separation efficiency is improved. Here, the process of separating the lubricating oil by the demista and the corelesser is the third step.

According to the invention of claim 4, even if the mixed fluid flowing from the gas inlet of the oil separator swirls in the outer cylinder shell, the ripple of the lubricating oil accumulated at the bottom of the outer cylinder shell and the refrigerant gas Since the entrainment in the lubricating oil is suppressed by the wave stop plate, the mixing of the refrigerant gas into the lubricating oil can be prevented. Therefore, it is possible to eliminate the adverse effect on the bearings and the like due to the supply of the lubricating oil mixed with the gas refrigerant to the screw compressor.

In addition, since the oil outlet was opened at a position away from the gas inlet for introducing the mixed fluid that may cause the lubricating oil level to undulate due to the swirling flow, the lubricating oil supplied from the oil outlet to the screw compressor The mixing of the refrigerant gas is prevented.

According to the fifth aspect of the present invention, since the gas outlet provided in the inner cylinder shell is opened on the downstream side of the downstream end face of the corelesser in the flow direction of the mixed fluid, the mixed fluid is vertically formed in the corelesser. It can flow almost uniformly along the line. Further, since the gas outlet and the oil return port are opened in the inner cylinder shell separated from the outer cylinder shell, the processing of the gas outlet into the inner cylinder shell is facilitated.

According to the invention of claim 6, the oil separator is based on the difference (differential pressure) between the internal pressure of the oil separator connected to the discharge side (high pressure side) of the screw compressor and the pressure on the suction side of the screw compressor. Since the differential pressure refueling method that supplies the lubricating oil to the screw compressor is adopted, the power consumption can be kept small and energy saving can be achieved compared to the forced refueling method using a pump.

It is a circuit diagram which shows the basic structure of the heat pump provided with the oil separator which concerns on this invention. It is a side sectional view of the oil separator which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 2 is a cross-sectional view taken along the line BB of FIG. It is a perspective view which shows the internal structure of the oil separator which concerns on Embodiment 1 of this invention. It is a side sectional view of the oil separator which concerns on Embodiment 2 of this invention. It is a side sectional view which shows an example of the conventional oil separator.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

[Heat pump configuration]
FIG. 1 is a circuit diagram showing a basic configuration of a heat pump including an oil separator according to the present invention. As shown in the figure, the heat pump 1 according to the present embodiment is a screw compressor along the flow direction of the refrigerant. 2. A closed-loop refrigerant circulation in which the oil separator 3, the water-cooled condenser 4, the liquid receiver 5, the liquid supply solenoid valve 6, the expansion valve 7, and the evaporator 8 according to the present invention are sequentially connected by the refrigerant pipes 9 to 14. It is composed by forming a circuit. The refrigerant pipe 14 is provided with a pressure sensor (P) 15 and a temperature sensor (T) 16 for detecting the pressure and temperature of the refrigerant flowing through the refrigerant pipe 14, respectively. Here, the pressure sensor (P) 15 and the temperature sensor (T) 16 are electrically connected to the gas superheat degree regulator (SH) 17, and the gas superheat degree regulator (SH) 17 is an electric valve. It is electrically connected to the expansion valve 7. The liquid supply solenoid valve 6 turns ON / OFF the circulation of the refrigerant in the refrigerant circulation circuit by fully opening (ON) / fully closing (OFF). In this embodiment, ammonia (NH ₃ ) is used as the refrigerant.

Further, as shown in FIG. 1, oil pipes 18 and 19 are led out from the oil separator 3, respectively, and a water-cooled oil cooler 20 is provided in the middle of one oil pipe 18. Then, one oil pipe 18 is connected to a bearing portion (not shown) inside the screw compressor 2 via an oil cooler 20, and the other oil pipe 18 is a refrigerant connected to the suction side of the screw compressor 2. It is directly connected to the pipe 14. In the present embodiment, the lubricating oil used for lubricating and cooling the screw compressor 2 is an alkylbenzene-based oil that is insoluble in the refrigerant (ammonia) and has a low oil vapor pressure in order to reduce oil rise. Oils such as Alkylbenzene) (hereinafter referred to as AB) are used (oil vapor is a gas, so it is difficult to separate oil).

[Oil separator configuration]
<Embodiment 1>
Here, the configuration of the oil filter 3 according to the first embodiment of the present invention will be described below with reference to FIGS. 2 to 5. 2 is a side sectional view of the oil separator according to the first embodiment of the present invention, FIG. 3 is a sectional view taken along line AA of FIG. 2, FIG. 4 is a sectional view taken along line BB of FIG. 2, and FIG. Is a perspective view showing the internal structure of the oil separator.

The oil separator 3 according to the first embodiment of the present invention separates the lubricating oil from the mixed fluid of the high-temperature and high-pressure refrigerant gas and the lubricating oil discharged from the screw compressor 2 shown in FIG. 1 to the refrigerant pipe 9. As shown in FIG. 2, the outer cylinder shell 21 in the shape of a closed container placed horizontally and the outer cylinder shell 21 from one end (right end in FIG. 2) in the longitudinal direction of the outer cylinder shell 21. It is provided with a bottomed cylindrical inner cylinder shell 22 inserted concentrically inside.

One end of the outer cylinder shell 21 in the longitudinal direction (left end in FIG. 2) is closed by an arcuate curved end plate 21a, and the insertion portion of the inner cylinder shell 22 at the other end in the longitudinal direction (right end in FIG. 2) is , Closed by a ring-shaped circular flat plate 23. The gas inlet 24 is tangent to the annular space S1 between the outer cylinder shell 21 and the inner cylinder shell 22 at the upper part of the outer cylinder shell 21 on the side where the inner cylinder shell 22 is inserted (on the right side in FIG. 2). It opens in the direction. As shown in FIG. 3, the gas inlet 24 is connected to the discharge side of the screw compressor 2 shown in FIG. 1 via a refrigerant pipe 9 horizontally connected to the outer cylinder shell 21.

Further, as shown in FIG. 2, an oil outlet 25 is opened at the bottom of the outer cylinder shell 21 and near the end plate 21a away from the gas inlet 24, and the oil outlet 25 is open. It is connected to a bearing portion (not shown) inside the screw compressor 2 via an oil pipe 18 and an oil cooler 20 shown in FIG. Then, as shown in FIG. 2, a wave stop plate 26 made of punching metal is vertically erected at the bottom of the outer cylinder shell 21 near the gas inlet 24.

By the way, as shown in FIGS. 2 and 5, two inner rings 34 having a notch ring shape are arranged on the inner peripheral surface of the outer cylinder shell 21 at predetermined intervals in the axial direction. Here, as shown in FIGS. 2 and 5, when the total length of gravity settling in the annular space S1 is x, the two inner rings 34 are located at locations (x / 3 intervals) that divide the total length of gravity settling x into three equal parts. Have been placed. The lower part of each inner ring 34 is cut out so as not to obstruct the flow of the lubricating oil collected at the bottom of the outer cylinder shell 21 (the notch length is set to about 1/4 of the total length of the inner ring 34). There is). The thickness of each inner ring 34 is set to 1.5 to 6.0 mm, and the height is set to about 1/3 (h / 3) of the gap h between the outer cylinder shell 21 and the inner cylinder shell 22.

On the other hand, in the inner cylinder shell 22, the end portion in the longitudinal direction (the left end portion in FIG. 2) of the portion inserted into the outer cylinder shell 21 is open, and the end portion of the portion protruding in the longitudinal direction from the outer cylinder shell 21. (Right end of FIG. 2) is closed by a blind flange 27. A corelesser 29 is housed and arranged in the inner cylinder shell 22. A ring-shaped partition plate 32 is attached to one end in the longitudinal direction (left end in FIG. 2) of the corelesser 29, and the other end in the longitudinal direction (right end in FIG. 2) of the corelesser 29 is a circle. It is closed by a plate-shaped lid plate 33. The inside of the inner cylinder shell 22 is divided into two spaces S2 and S3 by a partition plate 32.

Further, a gas outlet 30 is opened at the upper portion of the end portion (right end portion in FIG. 2) of the portion of the inner cylinder shell 22 that protrudes outward from the outer cylinder shell 21, and is inside the lower portion of the gas outlet 30. An oil return port 31 is opened at the bottom of the cylinder shell 22. Here, the gas outlet 30 is located on the downstream side (right side in FIG. 2) of the corelesser 29 on the downstream side end surface (right end surface in FIG. 2) in the flow direction of the mixed fluid in the inner cylinder shell 22 (right direction in FIG. 2). ) Is open. The gas outlet 30 is connected to the water-cooled condenser 4 shown in FIG. 1 via the refrigerant pipe 10, and the oil return port 31 is directly connected to the refrigerant pipe 14 shown in FIG. 1 via the oil pipe 19. ing.

By the way, as shown in FIGS. 2 and 5, two ring-shaped outer rings 35 are arranged on the outer peripheral surface of the inner cylinder shell 22 at predetermined intervals in the axial direction. Here, as shown in FIGS. 2 and 5, the two outer rings 35 are arranged at one end of the inner cylinder shell 22 (the left end in FIG. 2) and at the center of the total length of gravity settling x, and the outer rings 35 of these outer rings 35. The axial spacing is set to x / 2. The thickness of each outer ring 35 is set to 1.5 to 6.0 mm, and the height is set to about 1/3 (h / 3) of the gap h between the outer cylinder shell 21 and the inner cylinder shell 22.

<Embodiment 2>
Next, the configuration of the oil separator 3 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a side sectional view of the oil separator according to the second embodiment of the present invention. In this figure, the same elements as those shown in FIG. 2 are designated by the same reference numerals. The description of the above will be omitted again.

The oil separator 3 according to the present embodiment is characterized in that the demista 28 is housed and arranged on the upstream side of the corelesser 29 in the flow direction of the mixed fluid inside the inner cylinder shell 22, and the other configurations are FIG. This is the same as that according to the first embodiment shown in.

Here, the demista 28 is a separator that removes mist by inertially colliding with a thin wire having a wire diameter of about φ0.12 mm, and its contact surface area is as large as 1,780 m ² / m ³ and the spatial ratio is 94. It is as high as about 5%. Further, the corelesser 29 is a separator formed into a cylindrical shape, and separates the fine particles by, for example, brown (diffusion) movement of oil fine particles between 0.1 μm microglass fibers.

[Action of heat pump and oil separator]
Next, the operations of the heat pump 1 and the oil separator 3 will be described.

When the screw compressor 2 is driven by an electric motor (not shown) which is a drive source, the refrigerant gas sucked from the refrigerant pipe 14 is compressed by the screw compressor 2 (compression stroke), and is lubricated with the high temperature / high pressure refrigerant gas. The mixed fluid with the oil is discharged to the refrigerant pipe 9. Then, this mixed fluid is introduced from the refrigerant pipe 9 into the oil separator 3 to separate the lubricating oil. Specifically, in the oil separator 3 according to the first embodiment shown in FIGS. 2 to 5, the lubricating oil is the next first from the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor 2. ~ Separated through the third step.

That is, in the first step, the mixed fluid discharged from the screw compressor 2 to the refrigerant pipe 9 enters the annular space S1 between the outer cylinder shell 21 and the inner cylinder shell 22 from the gas inlet 24 of the oil separator 3. Since it flows in the tangential direction and swirls (cyclone motion) as shown by arrow a in FIGS. 2 and 3, lubricating oil having a specific gravity larger than that of the refrigerant gas flows along the inner surface of the outer cylinder shell 21 by centrifugal force. .. Here, the lubricating oil having a high viscosity falls because its flow velocity is reduced by the frictional resistance on the inner surface of the outer cylinder shell 21.

Thus, the flow of the lubricating oil along the inner surface of the outer cylinder shell 21 is blocked by the two inner rings 34 arranged on the inner circumference of the outer cylinder shell 21, so that the lubricating oil is supplied to the inner cylinder shell 22. Fall towards. Then, the lubricating oil that has fallen on the inner cylinder shell 22 flows along the outer surface of the inner cylinder shell 22 along the flow of the mixed fluid in the direction of arrow b in FIG. 2, and the flow of the lubricating oil is the inner cylinder shell 22. Since the lubricating oil is blocked by the two outer rings 35 arranged on the outer periphery of the inner cylinder shell 22, the lubricating oil falls from the outer surface of the inner cylinder shell 22 and falls to the bottom inside the outer cylinder shell 21 and is stored. As a result, the lubricating oil is effectively separated from the mixed fluid. In this first step, 95% or more of the lubricating oil is separated from the gas refrigerant. Incidentally, while the density ρg of the refrigerant gas (NH ₃ gas) is 9.45kg / ^{m 3,} the density ρo of the lubricating oil (PAG) shows a large value of 880 kg / ^{m 3.}

In the second step, the lubricating oil having a particle size of φ2 mm or less, which was not separated in the first step, accompanies the gas refrigerant and walks in the annular space S1 toward the end plate 21a of the outer cylinder shell 21 with the arrow b in FIG. As shown, it moves horizontally, but in the process, lubricating oil having a particle size of φ100 μm or more, which has a larger specific gravity than the gas refrigerant, separates from the gas refrigerant at the gravity settling length x1. That is, the mixed fluid flowing in the direction of arrow b in FIG. 2 collides with the end plate 21a, and the fine oil particle size grows large due to the action of the reversal of the flow direction and the surface tension of the lubricating oil, and the lubricating oil having a particle size of φ150 μm or more. Separates from the refrigerant gas at the gravity settling length x2, separates from the refrigerant gas by gravity and setstles, and the lubricating oil is separated from the refrigerant gas because it collects at the bottom of the outer cylinder shell 21.

In the third step, the mixed fluid from which a part of the lubricating oil is separated in the step 2 is introduced into the corelesser 29 from the space S2 in the inner cylinder shell 22, and the corelesser 29 is shown by an arrow d in FIG. The fine particles of the lubricating oil, which flow through the space S3 but were not separated in step 2, are separated by the corelesser 29.

As described above, since the lubricating oil contained in the mixed fluid is separated through the first to third steps, the oil separation performance of the oil separator 3 is improved.

Next, the separation of the lubricating oil in the oil separator 3 according to the second embodiment shown in FIG. 6 will be described.

Also in the oil separator 3 according to the second embodiment shown in FIG. 6, the lubricating oil contained in the mixed fluid in steps 1 and 2 is similar to the oil separator 3 according to the first embodiment shown in FIGS. Part of is separated.

Thus, in the oil separator 3 according to the second embodiment, in the third step, the mixed fluid flowing in the direction of arrow b in FIG. 6 collides with the end plate 21a and the flow direction is reversed, and this mixed fluid is shown in FIG. When introduced into the demister 28 as shown by the arrow c in 6, the lubricating oil having a particle size of φ3 to 100 μm is separated from the refrigerant gas by the inertial collision at the demister 28.

Then, the mixed fluid that has passed through the demista 28 is introduced into the corelesser 29 from the space S2 in the inner cylinder shell 22, passes through the corelesser 29 and flows into the space S3 as shown by an arrow d in FIG. The fine particles of the lubricating oil having a particle size of φ0.1 to 3 μm, which were not separated by the demista 28, are separated by the corelesser 29.

Therefore, in the oil separator 3 according to the second embodiment, the lubricating oil that was not separated in the second step is first separated from the refrigerant by the inertial collision at the demista 28, and then separated by the corelesser 29. The separation efficiency of the lubricating oil in the step is improved.

As described above, since the lubricating oil contained in the mixed fluid is separated through the first to third steps, the oil separation performance of the oil separator 3 is improved.

Further, in the oil separator 3 according to the first embodiment shown in FIGS. 2 to 5, the region where the lubricating oil is separated by the gravity settling motion in the first and second steps and the lubricating oil by the corelesser 29 in the third step. In the oil separator 3 according to the second embodiment shown in FIG. 6, the regions to be separated are arranged so as to overlap with each other in the longitudinal direction, and the regions for separating the lubricating oil by the gravity settling motion in the first and second steps. In the third step, since the region where the lubricating oil is separated by the demista 28 and the corelesser 29 is arranged so as to overlap in the longitudinal direction, the total length L of the oil separator 3 is shortened and the size of the oil separator 3 is reduced. be able to. For example, in the conventional oil separator 101 shown in FIG. 7, the gravity settling length x'is 1,890 mm and the total length L'is 3,500 mm, whereas the oil separator 3 according to the first and second embodiments of the present embodiment 3 The gravity settling length x1 is 1,000 mm, and the total length L of the oil separator 3 is about 1,650 mm, which is less than 1/2 of the total length L'(= 3,500 mm) of the conventional oil separator 101 shown in FIG. We were able to achieve miniaturization.

As a result of the above, according to the present invention, it is possible to obtain the effect that the oil separator 3 can be miniaturized while maintaining high oil separation performance.

By the way, the lubricating oil collected at the bottom of the outer cylinder shell 21 of the oil separator 3 flows from the oil outlet 25 to the oil pipe 18 as shown by the arrow f in FIGS. 2 and 6, and in the process, the oil cooler 20 After being cooled by, it is supplied to a bearing portion (not shown) in the screw compressor 2 and provided for lubrication. Further, the lubricating oil accumulated at the bottom of the inner cylinder shell 22 flows from the oil return port 31 to the oil pipe 19 as shown by the arrow g in FIGS. 2 and 6, and flows from the oil pipe 19 to the refrigerant pipe 14. It is introduced, is sucked by the screw compressor 2 together with the refrigerant gas flowing there, returns to the oil separator 3, and collects at the bottom of the outer cylinder shell 21 of the oil separator 3.

Here, in the present embodiment, oil is separated by the difference (differential pressure) between the internal pressure of the oil separator 2 connected to the discharge side (high pressure side) of the screw compressor 2 and the pressure on the suction side of the screw compressor 2. Since the differential pressure refueling method for supplying the lubricating oil from the vessel 3 to the screw compressor 2 is adopted, it is possible to obtain the effect that the power consumption can be suppressed to be smaller and the energy saving can be achieved as compared with the forced refueling method using the oil pump.

Thus, in the present embodiment, even if the mixed fluid flowing into the outer cylinder shell 21 from the gas inlet 24 of the oil separator 3 swirls in the outer cylinder shell 21, the bottom portion in the outer cylinder shell 21 is reached. Since the waviness of the accumulated lubricating oil is suppressed by the wave stop plate 26, it is possible to prevent the refrigerant gas from being mixed into the lubricating oil. Therefore, it is possible to eliminate the adverse effect on the bearings and the like due to the supply of the lubricating oil mixed with the gas refrigerant to the screw compressor 2.

Further, since the oil outlet 25 is opened at a position away from the gas inlet 24 for introducing the mixed fluid that may cause the lubricating oil level to undulate due to the swirling flow, the oil outlet 25 is supplied to the screw compressor 2. It is possible to prevent the refrigerant from being mixed into the lubricating oil.

Further, in the present embodiment, the gas outlet 30 provided in the inner cylinder shell 22 is located downstream of the downstream end surface (right end surface of FIGS. 2 and 6) of the corelesser 29 in the flow direction of the mixed fluid (FIGS. 2 and 6). Since the opening is made on the right side of FIG. 6), the mixed fluid can flow substantially uniformly along the longitudinal direction in the corelesser 29. Further, since the gas outlet 30 and the oil return port 31 are opened at the inner cylinder shell 22 separated from the outer cylinder shell 21, it is easy to process the gas outlet 30 and the oil return port 31 into the inner cylinder shell 22. The effect of becoming a gas can also be obtained.

Thus, the high-temperature and high-pressure refrigerant gas after the lubricating oil is separated by the oil separator 3 as described above is inside the inner cylinder shell 22 as shown by arrows e in FIGS. 2, 4 and 6. It is introduced into the water-cooled condenser 4 shown in FIG. 1 from the space S3 of the above through the refrigerant pipe 10, and the latent heat of condensation is released to the cooling water flowing through the water-cooled condenser 4 to liquefy it (condensation stroke). Here, the lubricating oil contained in the mixed fluid is separated from the refrigerant gas and removed by the oil separator 3 according to the present invention as described above, and only the refrigerant gas is introduced into the water-cooled condenser 4 for lubrication. The oil does not adhere to the heat transfer surface of the water-cooled condenser 4 and cause a decrease in heat exchange efficiency. As a result, the refrigerant gas in the water-cooled condenser 4 is efficiently liquefied. When the heat pump 1 is operated as a heater, heating is performed by the latent heat of condensation released from the water-cooled condenser 4.

Then, the high-pressure refrigerant liquid liquefied by the water-cooled condenser 4 as described above is sent to the liquid receiver 5 through the refrigerant pipe 11 and stored, and a part of the high-pressure refrigerant liquid is opened with the refrigerant pipe 12 ( It flows to the expansion valve 7 via the liquid supply solenoid valve 6 and the refrigerant pipe 13 in the ON) state, and adiabatic expansion (equal enthalpy expansion) is performed by the expansion valve 7 (expansion stroke).

The refrigerant liquid whose pressure has decreased due to the adiabatic expansion is introduced into the evaporator 8, and in this evaporator 8, the low-pressure liquid refrigerant takes the latent heat of evaporation from the surroundings and evaporates (vaporizes) (evaporation stroke). Here, since only the liquid refrigerant containing no lubricating oil is introduced into the evaporator 8, the lubricating oil does not adhere to the heat transfer surface of the evaporator 8 and cause a decrease in heat exchange efficiency. As a result, the liquid refrigerant is efficiently evaporated (vaporized) in the evaporator 8. When the heat pump 1 is operated as a cooler (refrigerator), the required cooling (freezing) is performed by the latent heat of vaporization taken from the surroundings by the evaporator 8.

Then, the low-pressure refrigerant gas evaporated in the evaporator 8 as described above is separated by the oil separator 3 and sucked into the screw compressor 2 through the refrigerant pipe 14 together with the lubricating oil supplied from the oil pipe 19. The screw compressor 2 compresses the oil again, and thereafter, the series of operations described above are repeated to continuously operate the heat pump 1. The pressure and temperature of the gas refrigerant vaporized by the evaporator 8 are detected by the pressure sensor (P) 15 and the temperature sensor (T) 16, respectively, and these detection signals are sent to the gas superheat degree regulator (SH) 17. Will be sent. Then, the gas superheat degree regulator (SH) 17 adjusts the opening degree of the expansion valve 7 based on the received detection signal, and adjusts the superheat degree of the refrigerant gas supplied from the refrigerant pipe 14 to the screw compressor 2. Adjust to.

1 Heat pump 2 Screw compressor 3 Oil separator 4 Water-cooled condenser 5 Recipient 6 Liquid supply solenoid valve 7 Expansion valve 8 Evaporator 9-14 Refrigerant piping 15 Pressure sensor (P)
16 Temperature sensor (T)
17 Gas superheat regulator 18, 19 Oil piping 20 Oil cooler 21 Outer cylinder shell 21a Outer cylinder shell end plate 22 Inner cylinder shell 23 Circular flat plate 24 Gas inlet 25 Oil outlet 26 Wave stop plate 27 Blind flange 28 Demista 29 Coaressa 30 Gas Outlet 31 Oil return port 32 Barrier plate 33 Lid plate 34 Inner ring 35 Outer ring L Overall length of oil separator S1 Circular space S2 Front of corelesser in inner cylinder shell (upstream side of corelesser) S3 After corelesser in inner cylinder shell (downstream side of corelesser) ) Space x Gravity settling total length of annular space x1 Gravity settling length of ring space x2 Gravity settling length in front of the corelesser (upstream side of the corelesser) in the inner cylinder shell

Claims (6)

It is for separating the lubricating oil from the mixed fluid of the refrigerant gas and the lubricating oil discharged from the screw compressor of the heat pump.
It is provided with a horizontally placed closed container-shaped outer cylinder shell and a bottomed cylindrical inner cylinder shell inserted into the outer cylinder shell from one end in the longitudinal direction of the outer cylinder shell.
At one end in the longitudinal direction of the outer cylinder shell, a gas inlet is opened in the tangential direction with respect to the annular space between the outer cylinder shell and the inner cylinder shell, and protrudes from the outer cylinder shell of the inner cylinder shell. Open a gas outlet at one end in the longitudinal direction of the part
An oil outlet is opened at the bottom of the outer cylinder shell, and an oil return port is opened at the bottom of a portion of the inner cylinder shell that protrudes from the outer cylinder shell.
An oil separator characterized in that a corelesser is housed and arranged inside the inner cylinder shell. The oil separator according to claim 1, wherein a plurality of ring-shaped inner rings and outer rings are arranged at intervals in the axial direction on the inner circumference of the outer cylinder shell and the outer circumference of the inner cylinder shell. The oil separator according to claim 1 or 2, wherein the demister is housed and arranged on the upstream side of the corelesser in the flow direction of the mixed fluid inside the inner cylinder shell. A wave stop plate is arranged at the bottom of the outer cylinder shell near the gas inlet, and the oil outlet is opened on the other end side in the longitudinal direction away from the gas inlet of the outer cylinder shell. The oil separator according to any one of claims 1 to 3. The oil separator according to any one of claims 1 to 4, wherein the gas outlet is opened to the downstream side of the downstream end surface of the corelesser in the flow direction of the mixed fluid. Any of claims 1 to 5, wherein the oil outlet is connected to a bearing portion inside the screw compressor via an oil cooler, and the oil return port is directly connected to the suction side of the screw compressor. Oil separator described in Crab.

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