KR101128791B1 - gear type compressor - Google Patents

Abstract

The present invention relates to a gear type compressor capable of improving the performance coefficient of a refrigeration system.

To this end, the present invention provides a compressor comprising: a driving unit; a gear type compression unit for compressing the refrigerant introduced from the evaporator by receiving the driving force of the driving unit; and a gear type expansion unit for expanding the refrigerant re- And a gear type compressor is provided.

Gear, compressor, internal gear, external gear, compression, expansion

Description

Gear type compressor

1 is a conceptual diagram showing the construction of a general refrigeration system;

Fig. 2 is a graph showing the P-h diagram of the refrigeration system of Fig. 1

3 is a cross-sectional view showing a configuration of a gear type compressor according to the present invention

Fig. 4A is a cross-sectional view taken along the line I-I in Fig. 3, and shows a cross-sectional view showing the geometrical shape of the internal gear and the external gear of the compression portion

Fig. 4B is a cross-sectional view taken along the line II-II in Fig. 3, and shows a cross-sectional view showing the geometrical shape of the internal gear and the external gear of the expansion portion

5 is a diagram of a refrigeration system to which the gear type compressor of the present invention is applied

6 is a graph comparing the torque change generated in the compressor of the present invention with the torque generated in the conventional compressor

Description of the Related Art [0002]

1: casing 100: suction pipe

110: Power terminal 120: Base plate

2: driving part 200:

210: rotor 220: shaft

3: Compression unit 300: Main bearing                 

300a: Suction port 310: Compression cylinder

320: external gear 320a: tooth groove

330 internal gear 330a teeth

340: compression plate 340a: discharge port

350: compression section suction pipe 360: compression section discharge pipe

4: Expansion part 400: Expansion plate

410: expansion cylinder 420: external gear

420a: Teeth groove 430: Inner gear

430a: Teeth 440: Sub-bearing

440a: Suction port 440b: Discharge port

450: Expansion part suction pipe 460: Expansion part discharge pipe

5: condenser 6: evaporator

The present invention relates to a compressor, and more particularly, to a gear-type compressor.

Generally, a compressor is a machine that receives power from an electric motor or a power generating device such as a turbine and compresses the air, refrigerant or other special gas to increase the pressure of the working fluid. In the air conditioner or the refrigerator It is widely used from general household appliances such as field to plant industry.

On the other hand, such a compressor is classified into a positive displacement compressor and a dynamic compressor or turbo compressor depending on the manner of compression.

Among them, the displacement type compressor widely used in the industrial field has a compression method of increasing the pressure through reduction of the volume. The applied compressors are again classified into reciprocating compressors and rotary compressors.

The reciprocating compressor compresses a working fluid by a piston reciprocating linearly in the cylinder, and has a merit that a high compression efficiency can be obtained with a relatively simple mechanical element. On the other hand, the dimensions and weight of the machine become large, and the reciprocating compressor has a limitation in rotational speed owing to the inertia of the piston, and there is a disadvantage that considerable vibration occurs due to the inertia force.

The rotary compressor compresses the working fluid by a roller which revolves inside the cylinder while being eccentric, and can obtain a high compression efficiency at a low speed as compared with the reciprocating compressor.

However, in order to change the flow rate at a constant rotation speed, the rotary compressor is required to discharge extra air or to throttle the intake air. Also, in order to increase the delivery pressure by the excess air, It becomes difficult.

If the gaps in each part are not very uniform, the compressed gas may leak and fail to exhibit its performance. In the case of abrasion, the performance deteriorates sharply. Therefore, highly precise machining is required. In addition, the bearings are liable to break due to the abrupt load due to the sudden pressure change.

That is, the rotary compressor and the reciprocating compressor have different characteristics and advantages and disadvantages.

On the other hand, a refrigeration cycle is a thermodynamic cycle, which is called a refrigeration cycle when it is intended to extract heat to a cold reservoir by applying work, and a system constituting such a refrigeration cycle is frozen System, which is mainly used in refrigerators, air conditioners, and the like.

1, the refrigeration system includes a compressor 30 for compressing refrigerant at a high temperature and a high pressure, a heat exchanger 30 for taking heat from the refrigerant compressed by the compressor 30 and discharging the refrigerant to the outside, An expansion valve (40) for expanding the pressure of the refrigerant adiabatically expanded from the condenser (50), a refrigerant passing through the expansion valve (40) And an evaporator 60 for evaporating the refrigerant.

2 is a graph showing the Ph diagram of the refrigeration system of FIG. 1, in which a work Wc is received from the outside to compress the refrigerant in the compressor 30 (1 → 4) (2 → 3) through the condenser 50 to the outside.

The refrigerant that has passed through the condenser 50 passes through the expansion device 20 and is thermally expanded (3 → 4). The refrigerant passing through the expansion device passes through the evaporator 60, (4 → 1), and the refrigerant passing through the evaporator 60 flows into the compressor 30 again.

The coefficient of performance (COP) of this refrigeration system is defined as the compressor work Wc for the calorie (Q _H ) absorbed at the low temperature, i.e., the evaporator 60.

Therefore, in order to construct an efficient refrigeration system, it is necessary to construct an efficient compressor together with selection of an appropriate refrigerant.

In recent years, the necessity of alternative refrigerant such as CO 2 has become very important because of the problem that the refrigerant, which is a refrigerant, breaks down the ozone layer. In this case, there is no fear of leakage during compression even when an alternative refrigerant is used, A compressor is required.

It is an object of the present invention to provide a compressor of a new structure capable of improving the coefficient of performance of a refrigeration system different from the conventional compressor structure.

In order to achieve the above object, the present invention provides a refrigerating machine comprising a driving part, a gear type compression part for receiving a driving force of a driving part and compressing a refrigerant introduced from the evaporator, And a gear-type expansion unit for expanding the gear-type compressor.                     

In this case, the driving unit is a motor including a stator and a rotor installed at the center of the stator and rotated when the stator is powered on.

The gear type compression unit includes: a main bearing fixed to a lower side of the motor; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space; An internal gear installed inside the external gear to compress the refrigerant while being engaged with the external gear to receive the driving force of the motor; And a compression plate installed to be connected to the lower portion of the compression cylinder.

Further, the external gear is formed to have more tooth grooves than the number of teeth of the internal gear rotated by being coupled to the motor shaft.

The main bearing is connected to a sub compression suction pipe connected to the main bearing to send the refrigerant to the inside space of the external gear.

A suction port is formed in the main bearing, and a discharge port is formed in the compression plate.

The compression plate is provided with a compression discharge pipe for sending the compressed refrigerant to the condenser.

The gear type expanding portion may include an expansion plate fixed to a lower side of the motor; An annular expansion cylinder provided so as to be connected to the lower portion of the expansion plate; An external gear rotatably disposed in the expansion cylinder inner space; An internal gear installed inside the external gear to expand the refrigerant while being engaged with the external gear to receive the driving force of the motor; And a sub-bearing connected to the lower portion of the expansion cylinder.

Further, an expander suction pipe is installed at one side of the sub bearing to allow the refrigerant passing through the condenser to flow into the expansion cylinder.

In addition, an expander discharge pipe is provided at the other side of the sub-bearing to send the expanded refrigerant to the evaporator.

Further, the sub-bearing is characterized in that a suction port and a discharge port are formed at predetermined positions, respectively.

Further, the external size of the expansion part is formed to be smaller than the external size of the compression part.

According to another aspect of the present invention, there is provided an electronic apparatus comprising: a casing; A driving unit installed inside the casing; A gear type compression unit that receives the driving force of the driving unit and compresses the refrigerant introduced from the evaporator; And a gear type expansion unit for expanding the refrigerant re-sucked through the next condenser discharged from the compression unit.

The driving unit may include a stator mounted on an inner wall of the casing, and a motor installed in the center of the casing to rotate the stator when power is applied thereto.                     

The gear type compression unit includes: a main bearing fixed to a lower side of a motor of the casing; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space; An internal gear installed inside the external gear to compress the refrigerant while being engaged with the external gear to receive the driving force of the motor; And a compression plate installed to be connected to the lower portion of the compression cylinder.

At this time, the external gear is formed to have a tooth groove larger than the number of teeth of the internal gear which is coupled to the motor shaft and rotates.

In addition, a suction pipe for introducing the refrigerant into the casing is installed at one side of the casing.

The main bearing is provided with a sub compression suction pipe connected to the main bearing to send the refrigerant flowing into the casing toward the compression cylinder, and the compressed refrigerant is sent to the condenser And a compression discharge pipe is installed.

A suction port is formed in the main bearing, and a discharge port is formed in the compression plate.

The gear type expansion portion may include an expansion plate installed at a lower portion of the compression plate of the gear type compression portion; An annular expansion cylinder provided so as to be connected to the lower portion of the expansion plate; An external gear rotatably disposed in the expansion cylinder inner space; An internal gear installed inside the outer gear to expand the refrigerant while being engaged with the outer gear by receiving the driving force of the motor; And a sub-bearing connected to the lower portion of the expansion cylinder.

At this time, an expander suction pipe is installed at one side of the sub bearing to allow the refrigerant passing through the condenser to flow into the expansion cylinder.

In addition, an expander discharge pipe is provided at the other side of the sub-bearing to send the expanded refrigerant to the evaporator.

Further, the sub-bearing is provided with a suction port and a discharge port at predetermined positions, respectively.

In addition, the external size of the expansion portion is formed to be smaller than the external size of the compression portion.

The driving unit may be installed outside the casing.

In accordance with another aspect of the present invention, A suction pipe installed on one side of the casing for introducing a refrigerant into the casing; a stator mounted on an inner wall of the casing; and a motor installed in the center of the casing to rotate the stator when power is applied thereto; A main bearing fixed to a lower side of the motor; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space and having a plurality of teeth formed on an inner peripheral surface thereof; An internal gear which is meshed with the inside of the external gear and to which the shaft of the motor is axially coupled; A compression plate installed to be connected to a lower portion of the compression cylinder; A sub compression suction pipe connected to the main bearing to send the refrigerant introduced into the casing into the compression cylinder interior space; A compression discharge pipe installed on the compression plate for sending the compressed refrigerant to the condenser; An expansion plate disposed adjacent to the lower portion of the compression plate; An expansion cylinder installed to be connected to the lower portion of the expansion plate; A sub-bearing disposed adjacent to the lower portion of the expansion cylinder; An expander suction pipe installed at one side of the sub bearing to allow the refrigerant passing through the condenser to flow into the expansion cylinder; And an expander discharge pipe installed on the other side of the sub-bearing to send the expanded refrigerant to the evaporator.

At this time, the external gear is formed to have a tooth groove larger than the number of teeth of the internal gear which is coupled to the motor shaft and rotates.

A suction port is formed in the main bearing, and a discharge port is formed in the compression plate.

Further, the sub-bearing is provided with a suction port and a discharge port at predetermined positions, respectively.

The external dimensions of the sub-bearing, the expansion cylinder, and the expansion plate are formed to be smaller than the external sizes of the main bearing, the compression cylinder, and the compression plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 3 to 6 attached hereto.

3 is a cross-sectional view showing a configuration of a gear type compressor according to the present invention.

4A is a cross-sectional view taken along a line I-I in FIG. 3, and FIG. 4B is a cross-sectional view taken along line II-II in FIG. 3, and is a sectional view showing geometries of an internal gear and an external gear of the compression portion and the expansion portion.

Meanwhile, FIG. 5 is a configuration diagram showing a configuration of a refrigeration system to which the gear type compressor of the present invention is applied.

A gear type compressor of the present invention comprises: a casing (1) having a predetermined space portion therein; A driving unit 2 installed in the casing 1; A gear type compression section (3) for receiving the driving force of the driving section (2) and compressing the refrigerant introduced from the evaporator (6); And a gear type expansion unit (4) for expanding the refrigerant re-sucked through the condenser (5) after being discharged from the compression unit (3).

The driving unit 2 includes a stator 200 mounted on the inner wall of the casing 1 and a rotor 210 installed at the center of the stator 200 to be rotated upon power application to the stator 200 through the power terminal 110, .

The gear type compression unit 3 (i.e., compression unit) includes: a main bearing 300 fixed to a lower side of the motor of the casing 1; An annular compression cylinder 310 installed adjacent to the lower portion of the main bearing 300; An external gear 320 rotatably positioned in the space inside the compression cylinder 310; An internal gear (330) installed inside the external gear (320) to receive the driving force of the motor and to rotate the external gear (320) while rotating the external gear (320); And a compression plate 340 connected to the lower portion of the compression cylinder 310.

At this time, a suction pipe 100 for introducing a refrigerant into the casing 1 is installed at one side of the casing 1.

A base plate 120 for installing a compressor is installed in the lower portion of the casing 1.

The main bearing 300 is connected to the main bearing 300 through a compression cylinder suction pipe connected to the main bearing 300 to send the refrigerant flowing into the casing 1 through the compression cylinder 310 to the inside space of the external gear 320, A compression discharge pipe 360 is installed in the compression plate 340 to send the compressed refrigerant to the condenser 5 side.

At this time, the compression section suction pipe 350 is installed so as to be exposed on the liquid surface of the oil filled in the casing 1.

That is, the oil on the upper and lower portions of the compression unit 3 is not filled separately but is compressed in the vertical direction on the outer circumferential surface of the compression cylinder 310, the main bearing 300 and the compression plate 340 And they communicate with each other through the groove (3g) portion so that they can exchange with each other.

The gear type expanding portion 4 (i.e., the expanding portion) includes an expansion plate 400 installed under the compression plate 340 of the gear type compression portion 3; An annular expansion cylinder 410 installed to be connected to the lower portion of the expansion plate 400; An external gear 420 rotatably disposed in the inner space of the expansion cylinder 410; An inner gear 430 installed inside the outer gear 420 to expand the refrigerant while being meshed with the outer gear 420 by receiving the driving force of the motor; And a sub-bearing (440) installed to be connected to the lower portion of the expansion cylinder (410).

An expander suction pipe 450 is installed at one side of the sub bearing 440 to allow the refrigerant passing through the condenser 5 to flow into the expansion cylinder 410.

An expander discharge pipe 460 is provided at the other side of the sub bearing 440 to send the expanded refrigerant to the evaporator 6 side.

A suction port 300a is formed in the main bearing 300 and a discharge port 340a is formed in the compression plate 340.

The sub-bearing 440 is formed with a suction port 440a and a discharge port 440b at predetermined positions.

On the other hand, the external size of the expanding part 4 is formed to be smaller than the external size of the compression part 3. [

That is, the external sizes of the sub-bearing 440, the expansion cylinder 410 and the expansion plate 400 are smaller than the external sizes of the main bearing 300, the compression cylinder 310, and the compression plate 340 desirable.

Accordingly, the operation of connecting the compression portion discharge pipe 360 to the compression plate 340 constituting the gear type compression portion 3 can be facilitated.

The reason why the external size of the gear type expanding portion 4 can be formed to be smaller than the external size of the compression portion 3 is that the gear size of the expanding portion 4 is smaller than the gear size of the compression portion 3 .

This is because of the difference in specific volume between the refrigerant flowing into the suction port 300a in the compression section 3 and the refrigerant flowing into the suction port 440a in the expansion section 4, Since the volume of the refrigerant flowing into the suction port 440a is small, the mass flow rate of the expansion process and the mass flow rate of the compression process must be equal to each other, the stroke volume of the expansion process must be smaller than the stroke volume of the compression process. This is because the gear size of the expanding portion 4 must be smaller than the gear size of the compression portion 3.

However, the difference in gear size is not directly related to the difference in the external size of the compression cylinder 310 and the expansion cylinder 410.

Hereinafter, the compressor operation of the present invention will be described with reference to FIGS. 3 to 6. FIG.

3 and 5, the refrigerant is compressed in the gear type compression section 3 according to the operation of the drive section 2. Then, the refrigerant compressed in the compression section 3 is condensed in the condenser 3, (5), and the heat is discharged to the outside while passing through the condenser (5).

The refrigerant that has passed through the condenser 5 flows into the expansion portion 4 of the compressor of the present invention through the flow path, and the refrigerant introduced into the expansion portion 4 expands in the process of passing through the expansion portion.

The refrigerant having passed through the expansion part 4 flows into the evaporator 6, and the refrigerant absorbs heat from the outside while passing through the evaporator 6.

The refrigerant having passed through the evaporator 6 flows again into the compression unit 3, and this series of flows is repeated to form a refrigeration cycle.

The compression and expansion actions performed by the compressor of the present invention during the refrigeration cycle will now be described in detail with reference to FIG.

First of all, when power is applied to a motor mounted on the inner wall of the casing 1 and the rotor 210 rotates by electromagnetic interaction with the stator 200, the suction pipe 100 installed at the upper end of the casing 1 the refrigerant flows into the casing 1 through the pipe.

The refrigerant introduced into the casing 1 is sent to the inner space of the outer gear 320 through the sub compression suction pipe 350 connected to the main bearing 300.

The refrigerant that has passed through the compression portion suction pipe 350 flows into the inner space of the outer gear 320 through the suction port 300a of the main bearing 300 communicated with the inner space of the outer gear 320. [

The refrigerant sent to the inner space of the external gear 320 is gradually compressed according to the rotation of the internal gear 330 which is shaft-coupled to the motor shaft 220 and then passes through the discharge port 340a formed in the compression plate 340 Is discharged through a compression unit discharge pipe (360) connected to the discharge port (340a) and sent to the condenser (5).

It is needless to say that the area of the discharge port 340a in the compression section 3 is smaller than the area of the suction port 300a.                     

On the other hand, the refrigerant that has undergone the heat exchange process in the condenser 5 is reintroduced into the gear type expansion portion 4 of the compressor of the present invention.

The refrigerant having undergone the heat exchange in the condenser 5 passes through the expansion part suction pipe 450 connected to one side of the sub bearing 440 and then flows through the suction port 440a of the sub bearing 440 to the external gear 420 And the refrigerant sent to the inner space of the outer gear 420 gradually expands in accordance with the rotation of the inner gear 430 which is shaft-coupled to the motor shaft 220, Is discharged through an expansion part discharge pipe (460) connected to the port (440b) and sent to the evaporator (6).

It is needless to say that the area of the discharge port 440b in the expansion part 4 is formed to be larger than the area of the suction port 440a.

It is preferable that the gear type compression section 3 and the gear type expansion section 4 are installed in one casing 1 as in the previous embodiment, .

The driving unit 2 may also be provided outside the casing 1. The driving unit 2 may be an electric motor that generates a rotational force by electric energy. Anything is possible.

4A is a cross-sectional view taken along the line I-I of FIG. 3, illustrating geometrical shapes of the internal gear 330 and the external gear 320 constituting the compression unit 3. As shown in FIG.

The outer gear 320 is formed to have more tooth grooves 320a than the number of teeth 330a of the inner gear 330 coupled to the motor shaft 220, The center of rotation and the center of rotation of the external gear 320 are eccentrically installed.

The tooth 330a of the inner gear 330 is smaller than the number of tooth grooves 320a of the outer gear 320 and the shape of the teeth 330a is a cycloid curve.

4B is a cross-sectional view taken along the line II-II in FIG. 3, illustrating the geometric shapes of the internal gear 430 and the external gear 420 constituting the expanding portion 4. As shown in FIG. The structures of the internal gear 430 and the external gear 420 of the expanding portion 4 are the same as those of the internal gear 330 and the external gear 320 of the compression portion 3 and only differ in size.

FIG. 6 is a graph comparing the torque change generated in the compressor of the present invention with the torque generated in the conventional compressor. In FIG. 6, the vertical axis represents a torque ratio (Tm) obtained by dividing each torque value T by an average value And the horizontal axis represents the rotation angle.

Referring to this, it can be seen that the amount of change in torque generated when the refrigerant is compressed by the compressor according to the structure of the present invention is significantly smaller than that of the compressor having other structures.

Particularly, in the gear type compressor of the present invention, when the external gears 320 and 420 are rotated together with the internal gears 330 and 430 when the refrigerant is compressed and expanded, the torque is balanced and vibration and noise are reduced.

In the gear type compressor of the present invention, the teeth 330a and 430a formed on the inner gears 330 and 430 and the tooth grooves 320a and 420a on the outer gear 320 and 420 sides , There is an effect that the force transmitted from the internal gear to the external gear is dispersed without being concentrated in any one place.                     

In the gear type compressor of the present invention, the teeth 330a and 430a formed on the internal gears 330 and 430 and the teeth grooves 320a and 420a on the external gears 320 and 420 are engaged with each other That is, the relative speed is small.

Meanwhile, in the gear type compressor of the present invention, the refrigerant to be used can be used as a refrigerant of carbon dioxide.

Carbon dioxide is used as a refrigerant for a long time and is not only toxic but also nonflammable. In addition, the price is low, the source is abundant and does not need to be recovered, it can be dissolved well with lubricating oil, and the amount of cooling per unit capacity is 5 times that of CFC R-22 to reduce the volume for generating the same cooling capacity The compression ratio is also reduced.

Accordingly, when the gear type compressor of the present invention is used, carbon dioxide is used as a refrigerant, so that the above advantages can be fully utilized.

As described above, the present invention can improve the coefficient of performance of the refrigeration system by providing the compressor of the gear type.

According to the present invention, since the refrigerant used in the compressor can be replaced with carbon dioxide, it is possible to realize an environmentally friendly compressor.

That is, carbon dioxide is a refrigerant that has a long operating time, is not only toxic but also nonflammable. In addition, the price is low, the source is abundant and does not need to be recovered, it can be dissolved well with lubricating oil, and the amount of cooling per unit capacity is 5 times that of CFC R-22 to reduce the volume for generating the same cooling capacity The compression ratio is also reduced.

In addition, the gear type compressor of the present invention is advantageous in reducing vibrations and noise during operation of the compressor due to the balance of the force and the torque of the internal gear and the external gear.

Claims (29)

A driving unit; A gear type compression unit that receives the driving force of the driving unit and compresses the refrigerant introduced from the evaporator; And a gear type expansion unit for expanding the refrigerant re-sucked through the next condenser discharged from the compression unit, The driving unit includes a stator and a motor provided in the center of the stator and configured to rotate when the stator is powered on, The gear- A main bearing fixed to a lower side of the motor; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space; An internal gear installed inside the external gear to compress the refrigerant while being engaged with the external gear to receive the driving force of the motor; And a compression plate provided so as to be connected to a lower portion of the compression cylinder, Wherein the main bearing is connected to a sub compression suction pipe connected to the main bearing to send the refrigerant to the inside space of the external gear. delete delete delete delete delete delete delete delete delete delete delete delete delete A casing; A driving unit installed inside the casing; A gear type compression unit that receives the driving force of the driving unit and compresses the refrigerant introduced from the evaporator; And a gear type expansion unit for expanding the refrigerant re-sucked through the next condenser discharged from the compression unit, The driving unit includes a stator mounted on the inner wall of the casing and a rotor provided in the stator center portion and rotated when the stator is powered on, The gear- A main bearing fixed to a lower side of the motor of the casing; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space; An internal gear installed inside the external gear to compress the refrigerant while being engaged with the external gear to receive the driving force of the motor; A compression plate installed to be connected to a lower portion of the compression cylinder; A sub compression suction pipe connected to the main bearing to send the refrigerant introduced into the casing into the compression cylinder interior space; And a compression discharge pipe installed on the compression plate to send the compressed refrigerant toward the condenser. delete delete delete delete delete delete delete delete delete A casing; A suction pipe installed at one side of the casing for introducing refrigerant into the casing; A motor mounted on the inner wall of the casing, and a motor installed in the center of the casing to rotate the stator when power is applied thereto; A main bearing fixed to a lower side of the motor; An annular compression cylinder disposed adjacent to the lower portion of the main bearing; An external gear rotatably disposed in the compression cylinder inner space and having a plurality of teeth formed on an inner peripheral surface thereof; An internal gear which is meshed with the inside of the external gear and to which the shaft of the motor is axially coupled; A compression plate installed to be connected to a lower portion of the compression cylinder; A sub compression suction pipe connected to the main bearing to send the refrigerant introduced into the casing into the compression cylinder interior space; A compression discharge pipe installed on the compression plate for sending the compressed refrigerant to the condenser; An expansion plate disposed adjacent to the lower portion of the compression plate; An expansion cylinder installed to be connected to the lower portion of the expansion plate; A sub-bearing disposed adjacent to the lower portion of the expansion cylinder; An expander suction pipe installed at one side of the sub bearing to allow the refrigerant passing through the condenser to flow into the expansion cylinder; And an expander discharge pipe installed on the other side of the sub-bearing to send the expanded refrigerant to the evaporator. delete delete delete delete

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