JP2011033239A - Heat transfer pipe, air conditioner and method for manufacturing the heat transfer pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer pipe which improves heat exchange efficiency and has a thin outer pipe, an air conditioner including the heat transfer pipe, and to provide a method for manufacturing the heat transfer pipe. <P>SOLUTION: The heat transfer pipe 1 includes: a first metallic pipe 10 formed of copper or copper alloy; a second metallic pipe 20 arranged outside the first metallic pipe 10 and formed of copper or copper alloy; and fins 12 arranged between the first metallic pipe 10 and the second metallic pipe 20. The first metallic pipe 10 serves as a flowing passage of a first refrigerant, and a space between the outer side of the first metallic pipe 10 and the inner side of the second metallic pipe 20 serves as a flowing passage of a second refrigerant having a pressure lower than that of the first refrigerant. The fins 12 are provided in contact with the outer side of the first metallic pipe 10 and the inner side of the second metallic pipe 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat transfer tube, an air conditioner, and a method for manufacturing a heat transfer tube. In particular, the present invention relates to a heat transfer tube, an air conditioner, and a method for manufacturing a heat transfer tube having a double tube structure including an inner tube and an outer tube.

  Conventionally, a heat exchanging part comprising an outer pipe, an inner pipe provided at intervals in the outer pipe, and a fin provided between the outer pipe and the inner pipe, and both ends of both the inner and outer pipes of the heat exchanging part A heat exchanger having a connector fixed to the portion, wherein the gap between the outer tube and the inner tube of the heat exchange section is a first fluid passage and the inner tube is a second fluid passage The heat exchanging portion has a straight portion, and at the straight portion of the heat exchanging portion, at least one portion of the outer tube is contracted over the entire circumference, and the inner tube is formed by the contraction of the outer tube. A heat exchanger fixed through fins is known (see, for example, Patent Document 1).

  In the heat exchanger described in Patent Document 1, at least one portion of the outer tube is contracted over the entire circumference in the straight portion of the heat exchange unit, and the inner tube is externally connected to the outer tube through fins by the contraction of the outer tube. Since it is fixed to the tube, it is possible to prevent the occurrence of rattling due to vibration and the generation of abnormal noise due to the occurrence of rattling.

JP 2009-41798 A

  However, since the heat exchanger described in Patent Document 1 is at least one portion of the outer tube, that is, only partially contracted, the inner tube is fixed through fins by the contracted portion of the outer tube. Since the part is also partial, there is a limit to improving heat transfer and heat exchange through the surface of the inner tube.

  Therefore, an object of the present invention is to provide a heat transfer tube having a thin outer tube, an air conditioner including the heat transfer tube, and a method for manufacturing the heat transfer tube, while improving heat exchange efficiency. .

  In order to achieve the above object, the present invention provides a first metal tube formed from copper or a copper alloy, a second metal tube disposed outside the first metal tube and formed from copper or a copper alloy, A fin provided between the first metal tube and the second metal tube, the first metal tube being a flow path for the first refrigerant, and between the outside of the first metal tube and the inside of the second metal tube The interval is a flow path of the second refrigerant having a pressure lower than the pressure of the first refrigerant, and the fin is a heat transfer tube provided in contact with the outside of the first metal tube and the inside of the second metal tube. Provided.

  In the heat transfer tube, the fin may be formed in a spiral shape outside the first metal tube.

  The heat transfer tube may further include a groove formed on the outer side of the first metal tube along a direction inclined with respect to the vertical direction of the fin.

  In the heat transfer tube, the fin is preferably integrated with the first metal tube.

  In the heat transfer tube, the first metal tube may have a groove or a corrugate formed inside.

  In the heat transfer tube, the direction in which the first refrigerant should flow and the direction in which the second refrigerant should flow are preferably different from each other.

  Moreover, in order to achieve the said objective, this invention is an air conditioner provided with the main circuit and the bypass circuit, Comprising: The compressor which compresses a refrigerant | coolant, The compressed refrigerant | coolant is cooled, and it becomes a 1st refrigerant | coolant A condenser, a branch section for branching the first refrigerant, and supplying the main circuit and the bypass circuit; and a pressure lower than the pressure of the first refrigerant by expanding the first refrigerant supplied to the bypass circuit. A bypass expansion mechanism that forms the second refrigerant and a supercooler through which the first refrigerant branched into the main circuit passes, and the supercooler passes through the first refrigerant branched into the main circuit A first metal tube formed of copper or a copper alloy, a second metal tube disposed outside the first metal tube and formed of copper or a copper alloy, and between the first metal tube and the second metal tube Between the outer side of the first metal tube and the inner side of the second metal tube. Ri, fins, air conditioner provided in contact with the outer side of the first metal tube and the inside of the second metal tube is provided.

  In the air conditioner, the fins are preferably formed in a spiral shape outside the first metal tube.

  In order to achieve the above object, the present invention provides a tube preparation step of preparing a first metal tube made of copper or a copper alloy and a second metal tube made of copper or a copper alloy, and an outer side of the first metal tube. A fin forming step of forming fins, an insertion step of inserting the first metal tube having the fins into the second metal tube, the diameter of the second metal tube is reduced from the outside of the second metal tube, and the tip of the fin is A reduction step of bringing into contact with the inner wall of the second metal tube, and the fin formation step is a heat transfer tube that forms fins having a length within a range in which the first metal tube having the fins can be inserted into the second metal tube. A manufacturing method is provided.

  In the heat transfer tube manufacturing method, in the fin forming step, the fins may be spirally formed outside the first metal tube.

  Moreover, the manufacturing method of the said heat exchanger tube can also prepare the 1st metal pipe by which the groove | channel was formed in the surface at a pipe | tube preparation process.

  In order to achieve the above object, the present invention provides a tube preparation step of preparing a first metal tube made of copper or a copper alloy and a second metal tube made of copper or a copper alloy, and an outer side of the first metal tube. A fin forming step for forming fins, and a press-fitting step for press-fitting the first metal tube having fins into the second metal tube, wherein the outer diameter of the first metal tube having fins is the second metal A method of manufacturing a heat transfer tube is provided that forms fins with a length that is greater than the inner diameter of the tube.

  In the heat transfer tube manufacturing method, in the fin forming step, the fins can be spirally formed outside the first metal tube.

  Moreover, the manufacturing method of the said heat exchanger tube can also prepare the 1st metal pipe by which the groove | channel was formed in the surface at a pipe | tube preparation process.

  In order to achieve the above object, the present invention provides a tube preparation step of preparing a first metal tube made of copper or a copper alloy and a second metal tube made of copper or a copper alloy, and an outer side of the first metal tube. A fin forming step for forming fins, a press-fitting step for press-fitting a first metal tube having fins into the second metal tube, a diameter of the second metal tube is reduced from the outside of the second metal tube, and the tip of the fin is A reduction step of bringing into contact with the inner wall of the second metal tube, and the fin formation step is a heat transfer tube that forms fins having a length within a range in which the first metal tube having the fins can be inserted into the second metal tube. A manufacturing method is provided.

  According to the heat transfer tube, the air conditioner including the heat transfer tube, and the method for manufacturing the heat transfer tube according to the present invention, the heat exchange efficiency can be improved, and the heat transfer tube with the thin outer tube, the heat transfer tube An air conditioner provided with a heat transfer tube manufacturing method can be provided.

It is sectional drawing of the heat exchanger tube which concerns on the 1st Embodiment of this invention. It is a figure which shows the outline | summary of the heat exchange of the heat exchanger tube which concerns on the 1st Embodiment of this invention. It is a figure which shows the flow of manufacture of the heat exchanger tube which concerns on the 1st Embodiment of this invention. It is a figure which shows the flow of manufacture of the heat exchanger tube which concerns on the modification of the 1st Embodiment of this invention. It is a schematic diagram of the partial cross section of the heat exchanger tube which concerns on the 2nd Embodiment of this invention. It is a schematic diagram of a structure of the air conditioner which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the heat exchanger tube which concerns on a comparative example. It is a figure which shows the outline | summary of the mode of the refrigerant | coolant which flows through the heat exchanger tube which concerns on the comparative example 1. FIG. It is a figure which shows the outline | summary of the mode of the refrigerant | coolant which flows through the heat exchanger tube which concerns on the comparative example 2. FIG.

[Summary of First Embodiment]
The heat transfer tube 1 according to the first embodiment of the present invention is a heat transfer tube used in a heat exchanger (that is, an air conditioner), a first metal tube 10 formed of copper or a copper alloy, and a first A second metal tube 20 disposed outside the metal tube 10 and formed of copper or a copper alloy; and a fin 12 provided between the first metal tube 10 and the second metal tube 20. The pipe 10 is a flow path of the first refrigerant 110, and a second pressure having a pressure lower than the pressure of the first refrigerant 110 is between the outside of the first metal pipe 10 and the inside of the second metal pipe 20. This is a flow path of the refrigerant 100, and the fins 12 are provided in contact with the outside of the first metal tube 10 and the inside of the second metal tube 20.

[First Embodiment]
(Outline of heat transfer tube 1)
FIG. 1: shows the outline | summary of the cross section of the heat exchanger tube which concerns on the 1st Embodiment of this invention.

  The heat transfer tube 1 according to the first embodiment includes a first metal tube 10 and a second metal tube 20 having fins 12 formed at predetermined positions on the outer surface 10a. Specifically, the heat transfer tube 1 is provided between the first metal tube 10, the second metal tube 20 disposed outside the first metal tube 10, and the first metal tube 10 and the second metal tube 20. The fin 12 is provided. The first metal pipe 10 is a flow path for the first refrigerant 110, and the pressure between the outside of the first metal pipe 10 and the inside of the second metal pipe 20 is lower than the pressure of the first refrigerant 110. This corresponds to the flow path of the second refrigerant 100. The fins 12 are provided in contact with the outside of the first metal tube 10 (ie, the outer surface 10a) and the inside of the second metal tube 20 (ie, the inner surface 20a). Further, the first metal tube 10 and the second metal tube 20 have a predetermined position (that is, the brazing portion 30) between the vicinity of the end of the first metal tube 10 and the vicinity of the end of the second metal tube 20. Are fixed to each other by being attached.

(First metal tube 10)
The first metal tube 10 is formed in a substantially cylindrical shape in a portion excluding the fins 12. The first metal tube 10 is formed of a material that is excellent in heat transfer, workability, and pressure resistance and can be brazed. Specifically, the first metal tube 10 is formed from copper or a copper alloy. And the 1st metal tube 10 has the fin 12 in the outer side of the 1st metal tube 10, ie, the outer surface 10a. The fin 12 extends in a direction perpendicular to the longitudinal direction of the first metal tube 10, away from the tube axis of the first metal tube 10, and is provided in a spiral shape. Moreover, although the 1st metal tube 10 can have the smooth inner surface 10b, in order to improve the heat transfer characteristic of the heat exchanger tube 1, the inner surface groove | channel 16 as a groove | channel or a corrugate is further provided in the inner surface 10b. Can also have.

(Fin 12)
The fins 12 are formed to extend from the outer surface 10a of the first metal tube 10 toward the inner surface 20a of the second metal tube 20. The fin 12 has a bent portion 12b in the vicinity of the inner surface 20a, and the tip 12a of the fin 12 is provided in contact with the inner surface 20a of the second metal tube 20a. That is, the tip 12a of the fin 12 and the inner surface 20a are in contact with each other at the contact portion 14 having a predetermined length. Further, since the fin 12 is formed by processing the outside of the first metal tube 10, the fin 12 and the first metal tube 10 are integrated. The fins 12 can be formed in the vicinity of both end portions of the first metal tube 10, that is, in the region excluding the region corresponding to the brazing portion 30.

(Second metal pipe 20)
The second metal tube 20 is formed to have an introduction port into which the second refrigerant 100 is introduced and a discharge port from which the second refrigerant 100 is discharged, and has a substantially cylindrical shape. The second metal tube 20 is formed of a material that is excellent in heat transfer, workability, and pressure resistance and can be brazed, like the first metal tube 10. Specifically, the second metal tube 20 can be formed from copper or a copper alloy. The second metal tube 20 can also be formed with a thickness that is thinner than the thickness of the first metal tube 10.

(Refrigerant flow)
The direction in which the first refrigerant 110 flowing through the first metal tube 10 should flow and the direction in which the second refrigerant 100 flowing through the second metal tube 20 should flow are different from each other. That is, the first refrigerant 110 flows in the first metal tube 10 in a predetermined direction. On the other hand, a gap portion between the outer surface 10a of the first metal tube 10 and the inner surface 20a of the second metal tube 20 (Note that, since this gap portion is annular in the cross section, it will be referred to as “annular portion” in the following description. The second refrigerant 100 flows in the opposite direction of the flow of the first refrigerant 110.

(About heat exchange of heat transfer tube 1)
FIG. 2 shows an outline of heat exchange of the heat transfer tubes according to the first embodiment of the present invention.

  In the heat transfer tube 1 according to the first embodiment, the first refrigerant 110 (that is, the mainstream refrigerant) flows through the first metal tube 10. The annular portion between the outer surface 10a of the first metal tube 10 and the inner surface 20a of the second metal tube 20 has a second refrigerant 100 (that is, bypass) having a lower temperature and lower pressure than the first refrigerant 110. Circulating refrigerant). When the first refrigerant 110 having a higher temperature and higher pressure than the second refrigerant 100 is circulated in the first metal tube 10 and the second refrigerant 100 having a lower temperature and lower pressure than the first refrigerant 110 is circulated through the annular portion. The liquid second refrigerant 100 flows in a predetermined region “A” in the vicinity of the outer surface 10 a of the first metal tube 10. The liquid second refrigerant 100 also flows in a predetermined region “C” in the vicinity of the inner surface 20 a of the second metal tube 20. On the other hand, the gaseous second refrigerant 100 flows in a region “B” between the region “A” and the region “C”.

  Here, the liquid second refrigerant 100 flowing in the region “A” can cool the first refrigerant 110 flowing in the first metal tube 10. Further, as shown in FIG. 2, the tip 12a of the fin 12 contacts the inner surface 20a with a contact portion 14. That is, since the outer surface 10a and the inner surface 20a are connected via the fins 12 in the first embodiment, the liquid second refrigerant 100 flowing in the region “C” is placed on the side surface 14a of the fins 12. And moves toward the region “A” like the refrigerant flow 120 shown in FIG. 2. That is, in the heat transfer tube 1 according to the first embodiment, the second refrigerant 100 in the region “C” is transmitted through the side surface 14a of the fin 12 and is higher in the region “C” than the second refrigerant 100 flowing in the region “C”. It merges with the second refrigerant 100 flowing through “A”. Therefore, the second refrigerant 100 flowing through the region “C” can also directly contact the outer surface 10a of the first metal tube 10 and contribute to heat exchange.

  Further, the fin 12 connects the outer surface 10a of the first metal tube 10 and the inner surface 20a of the second metal tube, and the surface of the fin 12 and the second refrigerant 100 are in contact with each other, so there is no fin 12. Compared to the case, the contact area between the second refrigerant 100 and the surface of the first metal tube 10 increases. Furthermore, since the fin 12 is formed from copper or a copper alloy having a high thermal conductivity, the fin 12 itself contributes to the improvement of the heat exchange efficiency.

[Summary of Manufacturing Method of Heat Transfer Tube 1]
In the manufacturing method of the heat exchanger tube 1 used for a heat exchanger, the pipe | tube preparation process which prepares the 1st metal pipe 10 which consists of copper or a copper alloy, and the 2nd metal pipe 20 which consists of copper or a copper alloy, and a 1st metal pipe A fin forming step of forming the fins 12 on the outer side of the first metal tube, an insertion step of inserting the first metal tube 10 having the fins 12 into the second metal tube 20, and the second metal tube 20 from the outer side of the second metal tube 20. A reduction step of reducing the tube diameter and bringing the tip 12a of the fin 12 into contact with the inner wall of the second metal tube 20. The fin formation step inserts the first metal tube 10 having the fin 12 into the second metal tube 20. The fin of the length of the range which can do is formed.

(Method for manufacturing heat transfer tube 1)
FIG. 3 shows an example of the flow of manufacturing the heat transfer tube according to the first embodiment of the present invention.

  First, the first metal tube 10 and the second metal tube 20 are prepared (tube preparation process: step 10, hereinafter, step is referred to as “S”). As an example, when the first metal tube 10 after the fin 12 is formed is inserted into the second metal tube 20, the tip 12a of the fin 12 does not contact the inner surface 20a of the second metal tube 20, or A second metal tube 20 having an inner diameter large enough to be inserted without resistance even if the tips 12a of the fins 12 are in contact with each other is prepared.

  Next, the fins 12 are formed outside the first metal tube 10 (fin formation step: S20). Specifically, the helical fin 12 is formed by cutting (for example, raising) the outer surface 10a of the first metal tube 10. Here, the fin 12 has a length within a range in which the first metal tube 10 having the fin 12 can be inserted into the second metal tube 20 (that is, the outer surface 10a of the first metal tube 10 in an insertion step described later). To the tip 12a of the fin 12).

  In the fin forming step, the fins 12 can be formed using a lathe, for example. That is, first, a notch having a predetermined depth is formed in the outer surface 10 a of the first metal tube 10. Next, a predetermined cutting tool is brought into contact with the cut formed in the outer surface 10a of the first metal tube 10, and the cutting tool is laterally fed while rotating the first metal tube 10 to cut the outer surface 10a. Fins 12 are formed. The fins 12 having a predetermined shape and a predetermined length can be formed by adjusting the cutting edge shape, cutting angle, cutting depth, and the like of the cutting tool.

  Subsequently, the first metal tube 10 having the fins 12 is inserted into the second metal tube 20 (insertion step: S30). Next, the diameter of the second metal tube 20 is reduced from the outside of the second metal tube 20 in which the first metal tube 10 is inserted (reduction process: S40). By this reduction process, the tips 12 a of the fins 12 come into contact with the inner surface 20 a that is the inner wall of the second metal tube 20. The reduction process can be continuously performed from the vicinity of one end of the second metal tube 20 to the vicinity of the other end. Further, the end of the first metal tube 10 and the end of the second metal tube 20 are brazed (brazing step: S50). Through the above steps, the heat transfer tube 1 according to the present embodiment is manufactured. Note that a brazing step can also be performed before the reduction step. That is, after the relative position of the first metal tube 10 with respect to the second metal tube 20 is determined by the brazing process, the reduction process can be performed.

(Modification of manufacturing method of heat transfer tube 1)
FIG. 4 shows an example of the flow of manufacturing the heat transfer tube according to the modification of the first embodiment of the present invention.

  The manufacturing method of the heat transfer tube 1 according to the modification of the first embodiment is the same as that of the first embodiment except that the method includes a tube preparation step, a fin formation step, a press-fitting step, and a brazing step. The same process as the manufacturing method of the heat exchanger tube 1 is provided. Therefore, a detailed description is omitted except for differences.

  In the method for manufacturing the heat transfer tube 1 according to the modification of the first embodiment, after the tube preparation step (S10) and the fin formation step (S20), the first metal tube 10 having the fins 12 is secondly formed. A press-fitting step of press-fitting into the metal tube 20 is provided (S35). Here, in the fin formation step, the outer diameter of the first metal tube 10 having the fins 12 (that is, from the tip 12a of the one fin 12 to the center of the first metal tube 10 as a symmetry point, A fin 12 having a length such that the distance to the tip 12a of another fin 12 provided at a symmetrical position or a substantially symmetrical position is larger than the inner diameter of the second metal tube 20 is formed. Therefore, by press-fitting the first metal tube 10 having the fins 12 into the second metal tube 20, the first metal tube 10 is inserted into the second metal tube 20 while the tips of the fins 12 are bent. As a result, the tips 12 a of the fins 12 come into contact with the inner surface 20 a of the second metal tube 20.

  In yet another modification of the method for manufacturing the heat transfer tube 1 according to the first embodiment, both the press-fitting step and the reduction step can be provided. That is, after the first metal tube 10 having the fins 12 is press-fitted into the second metal tube 20 (press-in step), the diameter of the second metal tube 20 is reduced from the outside of the second metal tube 20 (reduction step). You can also. By providing both the press-fitting step and the reduction step, the tips 12a of the plurality of fins 12 can be reliably brought into contact with the inner surface 20a of the second metal tube 20.

(Effects of the first embodiment)
According to the heat transfer tube 1 according to the first embodiment, since the helical fins 12 are provided on the outer surface 10a of the first metal tube 10, the second refrigerant 100 and the surface of the first metal tube 10 As the contact area increases, the heat transfer area can be increased. Since the fin 12 is in contact with the inner surface 20a of the second metal tube 20, heat can be transferred between the inner surface 20a of the second metal tube 20 and the fin 12, and the second metal tube 20 The inner surface 20a can also be used as a heat transfer surface. Thereby, the heat transfer tube 1 according to the present embodiment improves the heat exchange efficiency compared to the case where the fins 12 are not provided and the case where the tips 12a of the fins 12 are not in contact with the inner surface 20a of the second metal tube 20. Can be made. Therefore, the size of the heat transfer tube 1 (that is, the supercooler) can be reduced.

  Moreover, since the heat exchanger tube 1 which concerns on 1st Embodiment can flow the low voltage | pressure 2nd refrigerant | coolant 100 to a cyclic | annular part, the pressure which concerns on the 2nd metal tube 20 can be reduced, and 2nd metal The thickness of the tube 20 can be made thinner than the thickness of the first metal tube 10. Thereby, while being able to reduce the size of the heat exchanger tube 1, the weight of the heat exchanger tube 1 can be reduced.

  Furthermore, in the heat transfer tube 1 according to the first embodiment, since the tips 12a of the fins 12 are in contact with the inner surface 20a of the second metal tube 20, the second refrigerant 100 that has flowed into the annular portion is transferred. The heat tube 1 can move from one end to the other end along the spiral formed by the fins 12. Thereby, since the 2nd refrigerant | coolant 100 which flowed into the cyclic | annular part does not carry out a backflow etc., heat exchange efficiency can be improved.

[Second Embodiment]
FIG. 5 shows an outline of a partial cross section of a heat transfer tube according to the second embodiment of the present invention.

  Unlike the heat transfer tube 1 according to the first embodiment, the heat transfer tube according to the second embodiment is different from the heat transfer tube 1 according to the first embodiment except that a groove 18 is further formed in the first metal tube 10. The heat transfer tube 1 according to the above has substantially the same function and configuration. Therefore, a detailed description is omitted except for differences.

  In the heat transfer tube according to the second embodiment, a spiral groove 18 is formed on the surface of the first metal tube 10. A convex portion 18 a is formed on the inner surface 10 b of the first metal tube 10 at a position corresponding to the groove 18.

  The groove 18 can be manufactured as follows, for example. First, a metal tube having a smooth surface is prepared as the first metal tube 10 in the tube preparation step. Next, the said metal pipe is set to a rolling apparatus provided with the rolling roll which has a ring-shaped protrusion. Then, a rolling roll inclined at a predetermined angle with respect to the tube axis of the metal tube is brought into contact with the metal tube, or a fin 12 formed later (for example, fins are formed on the outer surface of the metal tube). In this case, assuming a direction in which the fin before the press-fitting process extends with respect to the outer surface, a rolling roll inclined so as to have a predetermined angle with respect to the extending direction is brought into contact with the metal tube. Next, the rolling roll is rotated while rotating the metal tube, and the groove 18 is formed on the surface of the metal tube by moving the rolling roll along the longitudinal direction of the metal tube. Along with the formation of the groove 18, a convex portion 18 a is formed on the inner surface 10 b corresponding to the groove 18.

  After manufacturing the first metal tube 10 having the grooves 18 in this way, the second embodiment is performed through a fin forming step, an insertion step and / or a press-fitting step, a reduction step, and a brazing step. The heat exchanger tube which concerns on a form can be manufactured. In the second embodiment, the order of the reduction process and the brazing process can be reversed as in the first embodiment. Since the heat transfer tube according to the second embodiment includes the spiral groove 18 on the surface of the first metal tube 10, the second refrigerant 100 in the annular portion is disposed not only in the circumferential direction of the tube but also in the tube axis direction. Can be moved along. Thereby, the heat exchanger tube according to the second embodiment can further improve the heat exchange efficiency.

[Summary of Third Embodiment]
In the air conditioner 2 including the main circuit 3 and the bypass circuit 4, the air conditioner 2 according to the third embodiment is a first compressor that cools the compressed refrigerant and the compressor 40 that compresses the refrigerant. The condenser 50 that is used as the refrigerant 110, the branch section 70 that branches the first refrigerant 110 and supplies it to the main circuit 3 and the bypass circuit 4, and the first refrigerant 110 that is supplied to the bypass circuit 4 is expanded. A bypass expansion mechanism 82 for forming the second refrigerant 100 having a pressure lower than the pressure of the first refrigerant 110, and a supercooler through which the first refrigerant 110 branched into the main circuit 3 passes. The cooler is formed of copper or a copper alloy that is formed from copper or a copper alloy through which the first refrigerant 110 branched to the main circuit 3 passes, and is formed from the copper or copper alloy that is disposed outside the first metal tube 10. Second metal tube 20, first metal tube 10 and second metal tube 2 The second refrigerant 100 passes between the outside of the first metal tube 10 and the inside of the second metal tube 20, and the fin 12 is connected to the first metal tube 10. In contact with the outside of the second metal tube 20 and the inside of the second metal tube 20.

[Third Embodiment]
FIG. 6 shows an outline of the configuration of an air conditioner according to the third embodiment of the present invention.

  The air conditioner 2 according to the third embodiment includes a main circuit 3 and a bypass circuit 4. The main circuit 3 includes a compressor 40 that compresses a gaseous refrigerant, a condenser 50 that cools the compressed refrigerant to form a liquid first refrigerant 110, and a double tube as a subcooler. Type heat transfer tube 1, main expansion mechanism 80 that expands the refrigerant, evaporator 60 that evaporates the liquid, four-way switching valve 72 that switches the path of the refrigerant, and accumulator 90 that serves as a gas-liquid separator. . Further, the bypass circuit 4 includes a bypass expansion mechanism 82 provided in a path branched from the main circuit 3 between the condenser 50 and the heat transfer tube 1 in the branch portion 70, and the vicinity of the inlet of the accumulator 90 through the heat transfer tube 1. A path to the junction 74 is provided. The bypass circuit 4 and the main circuit 3 merge at the merge unit 74. The heat transfer tube 1 according to the first embodiment or the heat transfer tube according to the second embodiment is used as a supercooler for the heat transfer tube 1 provided in the air conditioner 2.

  The refrigerant discharged from the compressor 40 is supplied to the condenser 50 via the four-way switching valve 72. The refrigerant supplied to the condenser 50 is condensed in the condenser 50. The refrigerant condensed in the condenser 50 is divided into a main flow refrigerant (that is, the first refrigerant 110) flowing in the main circuit 3 and a bypass flow refrigerant (that is, the second refrigerant 100) flowing in the bypass circuit 4 in the branching section 70. Branch to The mainstream refrigerant flows into the heat transfer tube 1 and is supercooled by heat exchange with the bypass flow refrigerant in a state where the heat transfer tube 1 passes through a bypass expansion mechanism 82 (for example, an expansion valve) and is decompressed. . Then, the subcooled mainstream refrigerant is supplied to the expansion mechanism unit 80. The expansion mechanism 80 decompresses the mainstream refrigerant by expanding it. Next, the decompressed mainstream refrigerant is evaporated in the evaporator 60, passes through the accumulator 90 via the four-way switching valve 72, and is supplied to the compressor 40.

  On the other hand, the bypass flow refrigerant is supplied to the heat transfer tube 1 after being depressurized by the bypass expansion mechanism 82. And the bypass flow refrigerant | coolant supplied to the heat exchanger tube 1 evaporates by heat exchange with the mainstream refrigerant | coolant in the heat exchanger tube 1 (namely, vaporizes). Thereafter, the bypass-flow refrigerant merges with the main-stream refrigerant at the merge section 74 and is supplied to the compressor 40 via the accumulator 90.

  As the heat transfer tube according to the example, a heat transfer tube corresponding to the heat transfer tube 1 according to the first embodiment was manufactured. That is, before manufacturing a heat transfer tube as a supercooler as the first metal tube 10 (that is, before being inserted into the second metal tube 20), the outer diameter of the fin 12 is 14 mm and the height of the fin 12 is 1.9 mm. A first metal tube 10 having a fin 12 pitch of 1.6 mm and a tube thickness of 1.09 mm was produced. On the other hand, a copper tube having an outer diameter of 14.59 mm and a wall thickness of 0.49 mm was prepared as the second metal tube 20. A heat transfer tube according to the example was manufactured from the first metal tube 10 and the second metal tube 20.

  In the heat transfer tube according to the example, the length in the tube axis direction of the contact portion 14 between the tip 12a of the fin 12 and the inner surface 20a of the second metal tube 20 was 0.2 mm. Thereby, the height of the fin 12 of the heat transfer tube according to the embodiment was 1.7 mm, which is 0.2 mm lower than the height before the first metal tube 10 is inserted into the second metal tube 20. . A spiral inner groove 16 is provided on the inner surface of the first metal tube 10 for the purpose of improving heat transfer characteristics. The main flow refrigerant flows in the first metal tube 10 of the heat transfer tube according to the embodiment, and the bypass flow refrigerant flows between the first metal tube 10 and the second metal tube, that is, in the annular portion. And the heat exchanger tube which concerns on an Example and the heat exchanger tube which concerns on the comparative example demonstrated below were compared.

(Comparative example)
FIG. 7 shows an outline of a cross section of a heat transfer tube according to a comparative example. 8 shows an outline of the state of the refrigerant flowing through the heat transfer tube according to Comparative Example 1, and FIG. 9 shows an outline of the state of the refrigerant flowing through the heat transfer tube according to Comparative Example 2.

  As shown in FIG. 7, the heat transfer tube 5 including the first metal tube 11 that does not have the fins 12 was manufactured as the heat transfer tube 5 according to the comparative example. The heat transfer tube 5 has substantially the same function and configuration as the heat transfer tube according to the embodiment except that the first metal tube 11 does not have the fins 12 on the outer surface 10a. However, the thickness of the second metal tube 20 of the heat transfer tube 5 according to the comparative example 1 has a thickness (that is, 0.84 mm) thicker than the thickness of the first metal tube 10 of the heat transfer tube according to the example. Formed. The heat transfer tubes according to Comparative Example 1 and Comparative Example 2 are both the same as the heat transfer tube 5 according to the Comparative Example, and the difference between the heat transfer tube according to Comparative Example 1 and the heat transfer tube according to Comparative Example 2 is the first The refrigerant flowing through the metal tube is different from the refrigerant flowing through the second metal tube.

  First, referring to FIG. In the heat transfer tube according to Comparative Example 1, the first metal tube 11 is used as the first refrigerant 110, and a refrigerant having a lower temperature and lower pressure than the second refrigerant 100 is allowed to flow. On the other hand, between the first metal tube 11 and the second metal tube 20, the second refrigerant 100 having a higher temperature and higher pressure than the first refrigerant 110 is allowed to flow. In this case, the liquid first refrigerant 110 flows in the region “E” in the vicinity of the inner surface of the first metal tube 11, and the high-temperature and high-pressure second refrigerant 100 in the annular portion can be cooled. On the other hand, the gaseous first refrigerant 110 flows in the region “D” of the central portion of the first metal tube 11. That is, the low-temperature side refrigerant, specifically, the first refrigerant 110 flowing in the first metal tube 11 moves in the first metal tube 11 in a two-layer structure of liquid and gas.

  The first refrigerant 110 evaporates by receiving heat from the second refrigerant 100 and stores latent heat. In this case, since the high-temperature, high-pressure second refrigerant 100 flows through the annular portion, the thickness of the second metal tube 20 has a thickness greater than a predetermined thickness for the purpose of improving pressure resistance. And is required to be formed. That is, in Comparative Example 1, the thickness of the second metal tube 20 must be increased.

  On the other hand, in the heat transfer tube according to Comparative Example 2 shown in FIG. That is, a refrigerant having a higher temperature and a higher pressure than the second refrigerant 100 is allowed to flow inside the first metal tube 11 as the first refrigerant 110. On the other hand, the second refrigerant 100 having a lower temperature and lower pressure than the first refrigerant 110 is passed through the annular portion. In this case, the liquid second refrigerant flows in the region “F” in the vicinity of the first metal tube 11. Further, the liquid second refrigerant also flows in the region “H” in the vicinity of the inner surface of the second metal tube 20. Then, the gaseous second refrigerant flows in the region “G” between the region “F” and the region “H”. In the heat transfer tube 5 according to Comparative Example 2, since the first metal tube 11 does not have the fins 12, the liquid second refrigerant flowing through the region “H” near the inner surface of the second metal tube 20 is There is no contact with the first metal tube 11. That is, in Comparative Example 2, the heat exchange efficiency is lowered due to the absence of the fins 12.

(Characteristics of heat transfer tube according to the embodiment)
The heat transfer tube according to the embodiment includes fins 12. Thereby, the heat transfer area outside the first metal tube 10 of the heat transfer tube according to the example increased about 4.4 times compared to the heat transfer tube 5 according to the comparative example. Moreover, since the inner surface 20a of the second metal tube 20 and the outer surface 10a of the first metal tube 10 are thermally connected via the fins 12, the inner surface 20a of the second metal tube 20 is also used as a heat transfer surface. Can be used. Thereby, the heat transfer area of the outer surface 10a of the first metal tube 10 of the heat transfer tube according to the example increased by about 4.9 times compared to the heat transfer tube 5 according to the comparative example. Therefore, the heat transfer area of the first metal tube 10 of the heat transfer tube according to the embodiment is significantly increased as compared with the comparative example, and the heat transfer of the inner surface 20a of the second metal tube 20 is also promoted. Exchange efficiency can be improved and the size of the heat transfer tube can be reduced.

  Further, the bypass flow refrigerant (that is, the second refrigerant 100) had a pressure of about 59% of that of the main flow refrigerant (that is, the first refrigerant 110). Therefore, instead of flowing the main flow refrigerant into the annular portion as in the heat transfer tube according to Comparative Example 1, the pressure applied to the second metal tube 20 is reduced to about 41 by flowing the bypass flow refrigerant as in the embodiment. % Could be reduced. Thereby, the thickness of the second metal tube 20 of the heat transfer tube according to the embodiment can be reduced from 0.84 mm to 0.49 mm of the thickness of the second metal tube 20 of the heat transfer tube 5 according to Comparative Example 1. It was.

  While the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

DESCRIPTION OF SYMBOLS 1 Heat transfer tube 2 Air conditioner 3 Main circuit 4 Bypass circuit 5 Heat transfer tube 10 1st metal tube 10a Outer surface 10b Inner surface 11 1st metal tube 11a Outer surface 12 Fin 12a Tip 12b Bending part 14 Contact part 14a Side surface 16 Inner surface groove 18 groove 18a convex portion 20 second metal tube 20a inner surface 30 brazing portion 40 compressor 50 condenser 60 evaporator 70 branching portion 72 four-way switching valve 74 confluence portion 80 main expansion mechanism portion 82 bypass expansion mechanism portion 90 accumulator 100 Second refrigerant 110 First refrigerant 120 Flow of refrigerant

Claims (15)

A first metal tube formed from copper or a copper alloy;
A second metal tube disposed outside the first metal tube and formed of copper or a copper alloy;
A fin provided between the first metal tube and the second metal tube;
The first metal pipe is a flow path of the first refrigerant;
Between the outside of the first metal tube and the inside of the second metal tube is a flow path of the second refrigerant having a pressure lower than the pressure of the first refrigerant,
The fin is a heat transfer tube provided in contact with the outside of the first metal tube and the inside of the second metal tube.   The heat transfer tube according to claim 1, wherein the fin is formed in a spiral shape outside the first metal tube.   The heat transfer tube according to claim 2, further comprising a groove formed on an outer side of the first metal tube along a direction inclined with respect to a vertical direction of the fin.   The heat transfer tube according to claim 3, wherein the fin is integrated with the first metal tube.   The heat transfer tube according to claim 4, wherein the first metal tube has a groove or a corrugate formed inside.   The heat transfer tube according to claim 5, wherein a direction in which the first refrigerant should flow and a direction in which the second refrigerant should flow are different from each other. An air conditioner comprising a main circuit and a bypass circuit,
A compressor for compressing the refrigerant;
A condenser that cools the compressed refrigerant into a first refrigerant;
A branch part for branching the first refrigerant and supplying the first refrigerant to the main circuit and the bypass circuit;
A bypass expansion mechanism that expands the first refrigerant supplied to the bypass circuit to form a second refrigerant having a pressure lower than the pressure of the first refrigerant;
A subcooler for passing the first refrigerant branched into the main circuit,
The subcooler is
A first metal pipe formed from copper or a copper alloy that passes the first refrigerant branched into the main circuit;
A second metal tube disposed outside the first metal tube and formed of copper or a copper alloy;
A fin provided between the first metal tube and the second metal tube;
Between the outside of the first metal tube and the inside of the second metal tube, the second refrigerant passes,
The fin is an air conditioner provided in contact with an outer side of the first metal tube and an inner side of the second metal tube.   The air conditioner according to claim 7, wherein the fin is formed in a spiral shape outside the first metal tube. A pipe preparation step of preparing a first metal pipe made of copper or a copper alloy and a second metal pipe made of copper or a copper alloy;
Forming a fin on the outside of the first metal tube;
An insertion step of inserting the first metal tube having the fins into the second metal tube;
Reducing the diameter of the second metal tube from the outside of the second metal tube, and bringing the tip of the fin into contact with the inner wall of the second metal tube,
The said fin formation process is a manufacturing method of the heat exchanger tube which forms the said fin of the length of the range which can insert the said 1st metal tube which has the said fin in the said 2nd metal tube.   The said fin formation process is a manufacturing method of the heat exchanger tube of Claim 9 which forms the said fin in the outer side of the said 1st metal tube helically.   The said pipe | tube preparation process is a manufacturing method of the heat exchanger tube of Claim 10 which prepares the said 1st metal pipe by which the groove | channel was formed in the surface. A pipe preparation step of preparing a first metal pipe made of copper or a copper alloy and a second metal pipe made of copper or a copper alloy;
Forming a fin on the outside of the first metal tube;
A press-fitting step of press-fitting the first metal pipe having the fins into the second metal pipe,
The said fin formation process is a manufacturing method of the heat exchanger tube which forms the said fin of the length from which the outer diameter of the said 1st metal tube which has the said fin becomes larger than the internal diameter of the said 2nd metal tube.   The heat transfer tube manufacturing method according to claim 12, wherein in the fin forming step, the fins are spirally formed outside the first metal tube.   The said pipe | tube preparation process is a manufacturing method of the heat exchanger tube of Claim 13 which prepares the said 1st metal pipe in which the groove | channel was formed in the surface. A pipe preparation step of preparing a first metal pipe made of copper or a copper alloy and a second metal pipe made of copper or a copper alloy;
Forming a fin on the outside of the first metal tube;
A press-fitting step of press-fitting the first metal pipe having the fins into the second metal pipe;
Reducing the diameter of the second metal tube from the outside of the second metal tube, and bringing the tip of the fin into contact with the inner wall of the second metal tube,
The said fin formation process is a manufacturing method of the heat exchanger tube which forms the said fin of the length of the range which can insert the said 1st metal tube which has the said fin in the said 2nd metal tube.

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