JPH09273824A - Air conditioning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a clogging or a malfunction of an electrically-operated expansion valve even when an HFC-base refrigerant and a composite oil as a refrigerator oil are used. SOLUTION: An air conditioning apparatus is constructed by connecting a compressor 28, a four-way valve 27, an outdoor heat exchanger 26, an electrically operated expansion valve 31, an indoor heat exchanger 30, a four way valve 27, an accumulator 29 and a compressor 28 in series. A bridge circuit 21 which is made of check valves is mounted in this air conditioning apparatus so as to restrict the flow direction of a refrigerant which passes through an electrically operated expansion valve 31 to one way irrespective of cooling or heating. Furthermore, the electrically operated expansion valve 31 has a construction which is provided with a needle valve body and the refrigerant is made to flow from the distal end side to the proximal end side of the needle valve body in the expansion valve 31. Accordingly, even when an HFC-base refrigerant in a liquid form and a composite oil in which impurities are dissolved or metal powders are dispersed are used under pressure, an infiltration of the refrigerant and the composite oil into spaces in and around coils, a rotor or a shaft of the electrically operated expansion valve 31 can be prevented so that a clogging or a malfunction of the electrically operated expansion valve 31 can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner which can use a hydrofluorocarbon (abbreviated as HFC) type refrigerant and synthetic oil as refrigerating machine oil.

[0002]

2. Description of the Related Art Conventionally, there is an air conditioner as shown in FIG. This air conditioner includes a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, an electric expansion valve 4, an indoor heat exchanger 5, a four-way switching valve 2, an accumulator 6 and a compressor 1, and a refrigerant pipe. It is configured by connecting with.

In this air conditioner, during cooling, the four-way switching valve 2 is switched as shown by the solid line so that the refrigerant flows as shown by the solid line arrow. The outdoor heat exchanger 3 functions as a condenser, while the indoor heat exchanger 5 functions as an evaporator. On the other hand, during heating, by switching the four-way switching valve 2 as shown by the broken line, the refrigerant flows as shown by the broken line arrow. The indoor heat exchanger 5 functions as a condenser, while the outdoor heat exchanger 3 functions as an evaporator. Therefore, the direction of the refrigerant flowing through the electric expansion valve 4 is opposite to that during cooling and during heating.

FIG. 5 shows an electric expansion valve using a needle valve body as the electric expansion valve 4. This electric expansion valve
A coil 10, a rotor 11 that is driven to rotate by the coil 10 and moves axially by a screw with rotation, and a shaft 12 that has one end coaxially attached to the rotor 11 and moves axially with the rotor 11; It is stored in the casing 13. The tip of the shaft 12 is projected into the chamber 14 that communicates with the joint 18, and the conical needle valve body 17 at the tip of the shaft 12 and the funnel shape provided on the inner peripheral surface of the joint 15 facing the chamber 14 are formed. Valve seat 16
Are configured to face each other. Thus, joint 1
5 or the high-pressure liquid refrigerant flowing in from the joint 18 passes through the gap between the needle valve body 17 and the valve seat 16 to be decompressed. The degree of pressure reduction at that time is adjusted by advancing and retracting the shaft 12 by the rotation of the rotor 11 and changing the size of the gap between the needle valve body 17 and the valve seat 16.

[0005]

However, the above conventional air conditioner has the following problems. That is, as described above, the direction of the refrigerant flowing through the electric expansion valve 4 is opposite to that during cooling and during heating. Therefore, for example, if the refrigerant flows from the joint 15 side into the chamber 14 during heating, the refrigerant flows from the joint 18 side into the chamber 14 during the refrigerant.

By the way, an HFC type refrigerant is used as a substitute for the hydrochlorofluorocarbon (hereinafter abbreviated as HCFC) type refrigerant R22, and a synthetic oil is used as a refrigerating machine oil.
When (ester oil, ether oil, alkylbenzene oil, carbonate oil, etc.) is used, impurities (processing oil, assembly oil, rust preventive oil, cleaning oil, etc. other than refrigerating machine oil) are dissolved due to its strong polarity. easy. Therefore, sludge is easily generated by taking in the metal powder. In particular, when an ester oil is used as the refrigerating machine oil, hydrolysis occurs in the presence of water to generate a carboxylic acid, so that sludge is likely to be generated during copper plating. Then, the sludge thus generated causes the expansion valve to be clogged or malfunction.

At this time, the inventor has a difference in the amount of sludge adhered depending on the flow direction depending on the structure of the electric expansion valve, such as an electric expansion valve using a needle valve element. For example, it was found from the results of various experiments that the electric expansion valve does not become clogged or malfunction even if an HFC-based refrigerant and synthetic oil are used.

The mechanism by which the amount of sludge adhered differs depending on the flow direction in the electric expansion valve using the needle valve element is as follows.

As described above, the impurities dissolved in the refrigerant / synthetic oil together with the refrigerant / synthetic oil cause the electric expansion valve 4 to operate.
Pass through. At that time, during heating, the high-pressure liquid refrigerant / synthetic oil from the condenser flows into the chamber 14 from the joint 15 side. In this case, as shown in FIG. 6, the impurities adhere to the upper portion 20 of the needle valve body 17 at the tip of the shaft 12 due to the reattachment phenomenon of the fluid flow, and take in the metal powder in the refrigerant. However, the needle valve body 17 and the valve seat 1
Since the gap with 6 is narrow and has an orifice shape, the flow velocity is increased. Therefore, a strong shearing force of the fluid acts on the adhering impurities and the metal powder, and the impurities incorporating the metal powder do not grow and accumulate.

On the other hand, during cooling, the high-pressure liquid refrigerant / synthetic oil from the condenser flows into the chamber 14 from the joint 18 side. In this case, as shown in FIG. 7, the high-pressure liquid refrigerant / synthetic oil in which the impurities are dissolved or the metal powder is dispersed enters the casing 13 by the pressure, and the coil 1
0, the rotor 11, the shaft 12, and the like. Then, in the case of the stop state or the pressure equalizing state, the pressure is reduced, and further, the coil 10 is heated by the heat generation to evaporate the refrigerant and the refrigerating machine oil. As a result, the above impurities dissolved in the refrigerant / synthetic oil and the dispersed metal powder are
0, between the rotor 11, the shaft 12, etc., and on the surface of the needle valve body 17. Then, the precipitated impurities take in the metal powder to generate sludge. Thus, the needle valve body 17 and the valve seat 16 are
That is, the gap between the shaft 12 and the shaft 12 is clogged, and the shaft 12 malfunctions.

Therefore, an object of the present invention is to provide an air conditioner in which the electric expansion valve does not become clogged or malfunction when an HFC type refrigerant and a synthetic oil as a refrigerating machine oil are used.

[0012]

In order to achieve the above object, the air conditioner of the invention according to claim 1 has a four-way switching valve
The outdoor heat exchanger, the electric expansion valve, and the indoor heat exchanger are sequentially connected by a refrigerant pipe, the four-way switching valve and the discharge port of the compressor are connected by a refrigerant pipe, and the four-way switching valve and the compressor are connected. In an air conditioner formed by connecting an inflow port with a refrigerant pipe, the electric expansion valve is provided with a rectifying circuit that regulates the direction of the refrigerant passing through the electric expansion valve in one direction regardless of whether the refrigerant is being cooled or heated. It has a structure in which the amount of sludge adhered when the refrigerant flows in one direction is smaller than the amount when the refrigerant flows in the other direction, and the direction of refrigerant flow is regulated in the one direction by the rectification circuit. It is characterized by

According to the above construction, the high-pressure liquid refrigerant from the condenser flows through the electric expansion valve in the direction in which the amount of sludge adhered is small irrespective of whether it is cooling or heating, due to the action of the rectifying circuit. As a result, the amount of sludge attached to the electric expansion valve is small, and the cooling operation or the heating operation can be performed without clogging or malfunction of the electric expansion valve.

The invention according to claim 2 is the air conditioner according to the invention according to claim 1, wherein the rectifier circuit is configured so that the direction of only the refrigerant passing through the electric expansion valve is set regardless of whether the direction is cooling or heating. An air conditioner characterized by being specified in the direction.

According to a third aspect of the present invention, in the air conditioner of the first aspect of the invention, the electric expansion valve has a needle valve body, and the flow direction of the refrigerant is the needle by the rectifying circuit. It is characterized in that the valve body is defined from the tip side to the root side.

According to the above construction, the high-pressure liquid refrigerant from the condenser is supplied from the tip end side of the needle valve element of the electric expansion valve by the action of the rectifying circuit regardless of whether it is cooling or heating, and the needle valve is used. It flows toward the base of the body. As a result, the high-pressure liquid refrigerant in which the impurities are dissolved or the metal powder is dispersed does not infiltrate into the drive section of the electric expansion valve. In this way, sludge is not generated due to precipitation of impurities and metal powder that have entered the drive part of the electric expansion valve due to decompression, and the cooling operation or the heating operation can be performed without clogging or malfunction of the electric expansion valve.

The invention according to claim 4 is the air conditioner of the invention according to claim 1, wherein the rectifying circuit comprises:
It is characterized by using a check valve bridge circuit.

The invention according to claim 5 is the air conditioner according to claim 1, characterized in that the refrigerant is an HFC type refrigerant. According to the above configuration, even if impurities are dissolved in the high-pressure liquid refrigerant from the condenser due to the strong polarity of the HFC-based refrigerant used, the impurities are dissolved or the metal powder is dispersed. The high-pressure HFC-based liquid refrigerant does not enter the drive section of the electric expansion valve.

The invention according to claim 6 is the air conditioner according to claim 5, wherein the HFC-based refrigerant is a single refrigerant of R410A and R407C, a mixed refrigerant of R33 and R125, and R33 and R134a. And a mixed refrigerant of R32, R125, and R134a.

The invention according to claim 7 is characterized in that, in the air conditioner of the invention according to claim 5, synthetic oil is used as refrigerating machine oil. According to the above configuration, impurities such as processing oil, assembly oil, rust preventive oil, cleaning oil, etc. dissolved by the high pressure HFC liquid refrigerant / synthetic oil from the condenser and the high pressure liquid refrigerant / synthetic oil dispersed in the above The metal powder that does not enter the drive unit of the electric expansion valve.

The invention according to claim 8 is the air conditioner according to the invention according to claim 7, wherein the synthetic oil is any one of ester oil, ether oil, alkylbenzene oil, carbonate oil and fluoro oil. Or ether oil,
It is characterized by being a mixed oil containing at least one of alkylbenzene oil, carbonate oil and fluorine oil.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. <First Embodiment> FIG. 1 is a refrigerant circuit diagram in an air conditioner of the present embodiment. This air conditioner is provided between two adjacent check valves 22 and 23 in a check valve bridge circuit 21 formed by annularly connecting four check valves 22 ,. , The outdoor heat exchanger 26, the four-way switching valve 27, the compressor 28, the accumulator 29, the four-way switching valve 27, the indoor heat exchanger 30, and the two adjacent check valve bridge circuits 21. The check valves 24 and 25 are sequentially connected. The check valve bridge circuit 21 is configured by connecting the adjacent check valves 22 and 25 and the check valves 23 and 24 via the electric expansion valve 31.

In the above structure, during cooling, the four-way switching valve 27 is switched as shown by a solid line so that the refrigerant flow path is changed from the compressor 28 to the four-way switching valve 27 to the outdoor heat exchanger 26 to the check valve. 22 → electric expansion valve 31 → check valve 24 →
Indoor heat exchanger 30 → four-way switching valve 27 → accumulator 2
9 → Compressor 28. That is, the refrigerant flows as indicated by the solid arrow.

On the other hand, at the time of heating, by switching the four-way switching valve 27 as shown by the broken line, the refrigerant flow path is as follows: compressor 28 → four-way switching valve 27 → indoor heat exchanger 30 →
The check valve 25 → the electric expansion valve 31 → the check valve 23 → the outdoor heat exchanger 26 → the four-way switching valve 27 → the accumulator 29 → the compressor 28. That is, the refrigerant flows as indicated by the dashed arrow. As a result, the direction of the refrigerant flowing through the electric expansion valve 31 is
The direction is the same regardless of whether it is cooling or heating.

As shown in FIG. 2, the electric expansion valve 31 has a structure using a needle valve element as in the electric expansion valve 4 shown in FIG. Then, the valve seat 38 in FIG.
The side joint 37 is connected between the adjacent check valves 22 and 25 in the check valve bridge circuit 21 via a refrigerant pipe.
On the other hand, the joint 40 is connected between the adjacent check valves 23 and 24 in the check valve bridge circuit 21 via a refrigerant pipe. Therefore, the electric expansion valve 31 is allowed to flow into the chamber 36 from the joint 37 side irrespective of whether it is cooling or heating.

The refrigerants used here are R22 and R4.
It is a mixed refrigerant with 10 A, and the refrigerating machine oil is the above synthetic oil. Therefore, impurities such as processing oil, assembly oil, rust preventive oil or cleaning oil are easily dissolved, and sludge is easily generated by taking in metal powder.

However, as shown in FIG. 2, in the air conditioner of the present embodiment, the high pressure liquid refrigerant from the condenser is used.
/ Synthetic oil is a joint 37 regardless of whether it is cooling or heating.
From the side (that is, from the tip side of the needle valve body 39) the chamber 3
Flow into 6. Therefore, as shown in FIG. 2, a high-pressure liquid refrigerant in which the above impurities are dissolved or metal powder is dispersed.
/ Synthetic oil is the coil 32 or rotor 33 of the electric expansion valve 31.
It does not enter between the shafts 34 and the like. At that time, as in the case shown in FIG. 6, the impurities adhere to the upper part of the needle valve body 39 at the tip of the shaft 34 and take in the metal powder due to the re-adhesion phenomenon of the fluid flow. Since the gap between the valve seat 38 and the valve seat 38 is narrow and has an orifice shape, a strong shearing force of the fluid acts on the attached impurities and the metal powder, and the impurities containing the metal powder grow and accumulate. There is no such thing. Further, the low-pressure two-phase refrigerant / synthetic oil that has passed through the gap between the needle valve element 39 and the valve seat 38 and has been decompressed is positively placed between the coil 32, the rotor 33, the shaft 34, etc. because of its low pressure. It doesn't get in. Therefore, the impurities and metal powder deposited by the depressurization are carried by the low-pressure two-phase refrigerant / synthetic oil flow from the joint 40 toward the evaporator.

As described above, in the present embodiment, the compressor 28, the four-way switching valve 27, the outdoor heat exchanger 26, the electric expansion valve 31, the indoor heat exchanger 30, the four-way switching valve 27, the accumulator 29 and The check valve bridge circuit 21 as the rectifying circuit is provided in the air conditioner in which the compressors 28 are sequentially connected so that the direction of the refrigerant passing through the electric expansion valve 31 is one direction. Further, a needle valve is used as the electric expansion valve 31, and the downward direction of the electric expansion valve 31 is set to the needle valve body 3
9 is defined from the tip side to the root side. Therefore,
When an HFC type refrigerant is used as the refrigerant and the synthetic oil is used as the refrigerating machine oil, the high pressure liquid refrigerant from the condenser /
The synthetic oil does not enter between the coil 32, the rotor 33, the shaft 34, etc. in the electric expansion valve 31, together with the dissolved impurities or the dispersed metal powder.
That is, by the pressure reducing action of the electric expansion valve 31,
The impurities and the metal powder do not deposit between the coil 32, the rotor 33, the shaft 34, etc. to form sludge.

That is, according to the air conditioner of the present embodiment, HF is used as an alternative refrigerant to the HCFC refrigerant.
It is possible to prevent clogging or malfunction of the electric expansion valve that occurs when a C-based refrigerant and a synthetic oil as refrigerating machine oil are used.

<Second Embodiment> FIG. 3 is a refrigerant circuit diagram in the air conditioner of the present embodiment. In this air conditioner, another check valve bridge circuit is provided in the air conditioner shown in FIG. First check valve bridge circuit 51,
The four-way switching valve 57, the compressor 58, the accumulator 59, the indoor heat exchanger 60, and the electric expansion valve 61 are the check valve bridge circuit 21, the four-way switching valve 2 in the air conditioner shown in FIG.
7, compressor 28, accumulator 29, indoor heat exchanger 30
And, the electric expansion valve 31 is connected in the same manner and functions in the same manner. Further, the electric expansion valve 61 has a structure using a needle valve body as shown in FIG. 2, and the joint 37 on the valve seat 38 side is provided with an adjacent check valve in the first check valve bridge circuit 51. 52 and 55 while connecting the joint 40 to the adjacent check valve 5 in the first check valve bridge circuit 51.
It is connected between 3,54.

In the present embodiment, four check valves 6
A second check valve bridge circuit 62, which is formed by annularly connecting the check valves 3 to 66, is interposed between the four-way switching valve 57 and the first check valve bridge circuit 51. At that time, two adjacent check valves 63, 64 in the second check valve bridge circuit 62 are provided.
Is connected to the four-way switching valve 57, while two adjacent check valves 65 and 66 are connected between two adjacent check valves 52 and 53 in the first check valve bridge circuit 51. ing. The adjacent check valves 63, 66 and the check valves 64, 65 of the second check valve bridge circuit 62 are connected via the outdoor heat exchanger 67.

In the above structure, during cooling, the four-way switching valve 57 is switched as shown by the solid line so that the flow path of the refrigerant flows from the compressor 58 to the four-way switching valve 57 to the check valve 6.
3-> outdoor heat exchanger 67-> check valve 65-> check valve 52-> electric expansion valve 61-> check valve 54-> indoor heat exchanger 60-> four-way switching valve 57-> accumulator 59-> compressor 58. That is, the refrigerant flows as indicated by the solid arrow.

On the other hand, at the time of heating, by switching the four-way switching valve 57 as shown by the broken line, the refrigerant flow path is as follows: compressor 58 → four-way switching valve 57 → indoor heat exchanger 60 →
Check valve 55-> electric expansion valve 61-> check valve 53-> check valve 66
→ Outdoor heat exchanger 67 → Check valve 64 → Four-way switching valve 57 → Accumulator 59 → Compressor 58. That is, the refrigerant flows as indicated by the dashed arrow. As a result, the electric expansion valve 6
The direction of the refrigerant flowing through 1 and the outdoor heat exchanger 67 is the same direction during cooling and during heating.

Here, as shown in FIG. 2, the electric expansion valve 61 has a structure using a needle valve element as in the electric expansion valve 4 shown in FIG. The refrigerant used is the HFC-based non-azeotropic refrigerant R407C, and the refrigerating machine oil is the above synthetic oil. Therefore, the above impurities are easily dissolved and sludge is easily generated by incorporating the metal powder. However, as described above, the downward direction of the electric expansion valve 61 is defined to be from the joint 37 on the valve seat 38 side to the other joint 40 (that is, from the tip end side of the needle valve body 39 to the root side).
Therefore, as shown in FIG. 2, the high-pressure liquid refrigerant / synthetic oil in which the impurities are dissolved or the metal powder is dispersed becomes the coil 32, the rotor 33, or the shaft 34 of the electric expansion valve 61.
There is no way to get in between. Also, as mentioned above,
The impurities and the metal powder attached to the upper portion of the needle valve body 39 do not grow and accumulate due to the action of the strong shearing force of the fluid. That is, according to the air conditioner of the present embodiment, it is possible to prevent clogging or malfunction of the electric expansion valve due to sludge that occurs when an HFC-based refrigerant and synthetic oil as refrigerating machine oil are used.

The direction of the refrigerant flowing through the outdoor heat exchanger 67 is the same direction during cooling and during heating. Therefore, the heat exchange by the outdoor heat exchanger 67 can be changed to the heat exchange by the counterflow, and the air conditioning capacity when using the non-azeotropic refrigerant can be increased and the coefficient of performance can be improved.

Thus, in the present embodiment, the compressor 58, the four-way switching valve 57, the outdoor heat exchanger 67, the electric expansion valve 61, the indoor heat exchanger 60, the four-way switching valve 57, the accumulator 59 and The first check valve bridge circuit 5 as the rectifying circuit is added to the air conditioner in which the compressor 58 is sequentially connected.
The first and second check valve bridge circuits 62 are provided so that the direction of the refrigerant passing through the electric expansion valve 61 and the outdoor heat exchanger 67 is one direction. Further, a needle valve body is used as the electric expansion valve 61, and the direction of the refrigerant passing through the electric expansion valve 61 is defined from the tip side of the needle valve body 39 to the root side. Therefore, when an HFC type refrigerant is used as the refrigerant and the synthetic oil is used as the refrigerating machine oil, impurities and dispersed metal powder dissolved in the high pressure liquid refrigerant / synthetic oil from the condenser are The coil 32 of the electric expansion valve 61, the rotor 33, and the shaft 3 together with the high-pressure liquid refrigerant / synthetic oil.
It does not enter between the 4th magnitude.

That is, according to the air conditioner of the present embodiment, it is possible to prevent clogging or malfunction of the electric expansion valve due to sludge that occurs when an HFC-based refrigerant and synthetic oil as refrigerating machine oil are used. Further, the direction of the refrigerant flowing through the outdoor heat exchanger 67 is set to be the same regardless of whether it is cooling or heating, and the counterflow makes it possible to enhance the air conditioning capacity when a non-azeotropic refrigerant is used to improve the coefficient of performance. it can.

That is, according to each of the above embodiments, the HF
Improves the reliability of air conditioners that use C-based refrigerants,
This makes it possible to use an HFC refrigerant as an alternative refrigerant to the CFC refrigerant R22.

In each of the above embodiments, the check valve bridge circuit is used as the rectifier circuit that regulates the direction of the refrigerant passing through the electric expansion valve and the outdoor heat exchanger.
It is not limited to this. Further, as an example of the electric expansion valve having a structure in which the amount of sludge adhered when the refrigerant flows in one direction is smaller than the amount of sludge adhered when the refrigerant flows in the other direction, an electric expansion valve using a needle valve element is used. Shows. However, the present invention is not limited to this.

In each of the above embodiments, the HF
R410A and R407C are used as C-based refrigerants, but R33, R125, R134a, R407C, R410
A, R410B and the like may be used alone or may be appropriately mixed and used. Needless to say, each of the above air conditioners has the same effect even when an HCFC-based refrigerant is used as the refrigerant. Further, as the synthetic oil, any one of ester oil, ether oil, alkylbenzene oil, carbonate oil and fluorine oil, or a mixture containing at least one of ether oil, alkylbenzene oil, carbonate oil and fluorine oil. Oil can be used.

[0041]

As is clear from the above, in the air conditioner of the invention according to claim 1, the amount of sludge adhered by the rectifying circuit is maintained regardless of whether the direction of the refrigerant passing through the electric expansion valve is cooling or heating. Since the amount of sludge adhered to the electric expansion valve is reduced, the clogging and malfunction of the electric expansion valve can be prevented.

That is, according to the present invention, the reliability of the electric expansion valve is improved, and the HFC refrigerant can be used as a substitute refrigerant for the HCFC refrigerant R22.

Further, the rectifier circuit in the air conditioner according to the second aspect of the present invention regulates the direction of only the refrigerant passing through the electric expansion valve to one direction regardless of whether it is during cooling or heating. It is possible to accurately improve the reliability of the electric expansion valve by defining the direction of only the refrigerant that passes through the electric expansion valve.

Further, the electric expansion valve in the air conditioner of the invention according to claim 3 has a needle valve body, and the flow-down direction of the refrigerant is regulated by the rectifying circuit from the tip side of the needle valve body to the root side. Therefore, the high-pressure liquid refrigerant from the condenser can flow from the tip side to the root side of the needle valve element in the electric expansion valve regardless of whether it is cooling or heating. Therefore, it is possible to prevent the high-pressure liquid refrigerant, in which the impurities are dissolved or the metal powder is dispersed, from entering the drive unit of the electric expansion valve. As a result, sludge is not generated in the drive unit of the electric expansion valve due to deposition of the impurities and metal powder that have infiltrated into the drive unit of the electric expansion valve due to decompression, and clogging or operation of the electric expansion valve is prevented. Defects can be prevented.

Further, in the air conditioner of the invention according to claim 4, since the check valve bridge circuit is used as the rectifying circuit which defines the downflow direction of the electric expansion valve, a simple circuit using the check valve is used. The downward direction of the electric expansion valve can be defined.

Further, in the air conditioner of the invention according to claim 5, an HFC type refrigerant is used as the refrigerant, and the downward direction of the electric expansion valve is regulated from the tip side to the root side of the needle valve element. As a result, the reliability of the electric expansion valve is improved, so that it is possible to provide a highly reliable air conditioner using a refrigerant that replaces the HCFC refrigerant.

Further, according to the air conditioner of the invention as claimed in claim 6, R410A and R4 are used as the HFC refrigerant.
07C simple substance refrigerant, mixed refrigerant of R33 and R125, R
Refrigerant mixed with 33 and R134a, R32, R125 and R
The reliability when any one of the mixed refrigerants with 134a is used can be improved.

Further, in the air conditioner of the invention according to claim 7, when synthetic oil is used as the refrigerating machine oil, the processing oil dissolved in the high pressure HFC liquid refrigerant / synthetic oil due to the presence of the synthetic oil. Therefore, HFC refrigerant / synthetic oil is used by preventing impurities such as assembly oil, rust preventive oil or cleaning oil and dispersed metal powder from entering the drive part of the electric expansion valve to generate sludge. The reliability of the electric expansion valve at the time can be improved.

Further, in the air conditioner of the invention according to claim 8, as the synthetic oil, any one of ester oil, ether oil, alkylbenzene oil, carbonate oil and fluorine oil, or ether oil, alkylbenzene oil, Reliability can be improved when a mixed oil containing at least one of a carbonate oil and a fluorine oil is used.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment of an air conditioner of the present invention.

FIG. 2 is a diagram showing a structure of an electric expansion valve in FIG.

FIG. 3 is a refrigerant circuit diagram showing an embodiment different from FIG.

FIG. 4 is a refrigerant circuit diagram in a conventional air conditioner.

5 is a diagram showing the structure of the electric expansion valve in FIG.

6 is an explanatory view of a state of the electric expansion valve shown in FIG. 5 during heating.

7 is an explanatory view of a state of the electric expansion valve shown in FIG. 5 during cooling.

[Explanation of symbols]

21, 51, 62 ... Check valve bridge circuit, 22-25, 5
2 to 55, 63 to 66 ... Check valve, 26, 67 ... Outdoor heat exchanger, 27, 57 ... Four-way switching valve, 28, 58 ... Compressor, 30, 60 ... Indoor heat exchanger, 3
1,61 ... Electric expansion valve, 32 ... Coil, 33
… Rotor, 34… Shaft, 35
… Casing, 39… Needle valve body,
37, 40 ... Joint, 38 ... Valve seat.

Claims (8)

[Claims] 1. A four-way switching valve (27, 57), an outdoor heat exchanger
(26,67), the electric expansion valve (31,61) and the indoor heat exchanger (30,60) are sequentially connected by a refrigerant pipe,
(27, 57) and the discharge port of the compressor (28, 58) are connected by a refrigerant pipe, and the four-way switching valve (27, 57) and the compressor (2
In the air conditioner in which the inlet of (8,58) is connected by a refrigerant pipe, the direction of the refrigerant passing through the electric expansion valve (31,61) is regulated in one direction regardless of whether it is cooling or heating. Along with the circuit, the electric expansion valve (31, 61) has a structure in which the amount of sludge adhered when the refrigerant flows in one direction is smaller than the amount of sludge adhered when the refrigerant flows in the other direction. An air conditioner characterized in that the flow-down direction of the refrigerant is defined in the one direction by the rectifying circuit. 2. The air conditioner according to claim 1, wherein the rectifying circuit defines the direction of only the refrigerant passing through the electric expansion valve (31, 61) as one direction regardless of whether it is in cooling or heating. An air conditioner that is characterized by 3. The air conditioner according to claim 1, wherein the electric expansion valve (31, 61) has a needle valve body (39), and the flow direction of the refrigerant is the needle valve by the rectification circuit. An air conditioner characterized in that the body (39) is defined from the tip side to the root side. 4. The air conditioner according to claim 1, wherein the rectifier circuit is a check valve bridge circuit (21, 51).
An air conditioner characterized by using. 5. The air conditioner according to claim 1, wherein the refrigerant is a hydrofluorocarbon-based refrigerant. 6. The air conditioner according to claim 5, wherein the hydrofluorocarbon-based refrigerant is R410A.
And a single refrigerant of R407C, a mixed refrigerant of R33 and R125, a mixed refrigerant of R33 and R134a, R32 and R
An air conditioner characterized by being one of a mixed refrigerant of 125 and R134a. 7. The air conditioner according to claim 5, wherein synthetic oil is used as refrigerating machine oil. 8. The air conditioner according to claim 7, wherein the synthetic oil is any one of ester oil, ether oil, alkylbenzene oil, carbonate oil and fluoro oil, or ether oil, alkylbenzene oil, carbonate. An air conditioner, which is a mixed oil containing at least one of oil and fluorine oil.