JP2011075154A - Heat exchange unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchange unit preventing a leakage of a refrigerant, and achieving an improvement in pressure resistance strength. <P>SOLUTION: In a double pipe type heat exchanger 2 with an inner pipe 6 and an outer pipe 7, a first flow passage 8 and a second flow passage 9 are formed inside and outside the inner pipe 6. A header 3 is connected to the end of the outer pipe 7. The header 3 includes a space part 10 communicated with the second flow passage 9. In the header 3, a through-hole 11, in which the front end part 16 of the inner pipe 6 passes therethrough and comes out of the space part 10, is formed. On the periphery of the through-hole 11 on the outer surface of the header 3, a pipe expansion receiving part 13 is arranged. The pipe expansion receiving part 13 has an inner diameter larger than the outer diameter of the inner pipe 6 inside the space part 10. A part 17 that comes out of the space part 10 through the through-hole 11 in the front end part 16 of the inner pipe 6 is expanded so as to be closely contacted with the inner surface of the pipe expansion receiving part 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat exchange unit including a double tube heat exchanger having an inner tube and an outer tube.

  Conventionally, various heat exchange units have been proposed as economizer heat exchangers used in CO2 supercritical economizer cycles in heat pumps using CO2 refrigerants, etc., but heat exchange units that are particularly low cost and easy to form compactly. For example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-175449), a heat exchange unit in which a double-pipe heat exchanger having an inner tube and an outer tube is attached to a header is used.

  In this heat exchange unit, water (or other refrigerant) is passed through the inner pipe, and the CO2 refrigerant is passed through a plurality of refrigerant passages formed inside the pipe wall of the outer pipe. We are exchanging heat.

  When connecting a double-pipe heat exchanger to the header, insert the end of the outer tube into the header to allow the refrigerant flow path of the outer tube to communicate with the space inside the header, while the end of the inner tube Is connected to the external water pipe. In such a state, leakage of refrigerant or the like is prevented by welding or brazing the joint portion between the double-pipe heat exchanger and the header.

  However, the connection part of such a double-pipe heat exchanger and header has many welding and brazing joining process parts, and there is a risk of leakage of CO2 refrigerant and water from the joining part, and the pressure strength is insufficient. There is a problem of doing.

  An object of the present invention is to provide a heat exchange unit that prevents leakage of a refrigerant and the like and achieves improvement in pressure resistance.

  The heat exchange unit of the first invention includes a heat exchanger and a header. The heat exchanger has an inner tube and an outer tube disposed on the outer periphery of the inner tube, and the inner tube is longer than the outer tube. A first flow path and a second flow path are formed in the heat exchanger. The first flow path extends in the longitudinal direction of the inner tube inside the inner tube. The second flow path extends in the longitudinal direction of the inner tube between the inner tube and the outer tube. The header is connected to the end of the outer tube. The header has a space that communicates with the second flow path. The header is formed with a through hole through which the distal end portion of the inner tube passes and goes out of the space. A pipe expansion receiving portion is provided around the through hole on the outer surface of the header. The tube expansion receiving portion has an inner diameter larger than the outer diameter of the inner tube inside the space portion. Of the distal end portion of the inner tube, the portion that goes out of the space through the through hole is in close contact with the inner surface of the expanded tube receiving portion by being expanded.

  Here, a tube expansion receiving portion is provided around the through hole on the outer surface of the header, and a portion of the inner tube tip portion of the heat exchanger that goes out of the space portion through the through hole is expanded, thereby expanding the tube receiving portion. Since it is in close contact with the inner surface of the part, refrigerant leakage can be prevented at the joint part between the inner pipe and the header and the joint part between the inner pipe and the external connection pipe, and the pressure resistance is improved. Yes.

  The heat exchange unit of the second invention is the heat exchange unit of the first invention, and a connecting tube is inserted from the outside into the expanded portion of the tip portion of the inner tube. The tip portion of the inner tube and the connecting tube, and the tip portion of the inner tube and the pipe expansion receiving portion are collectively welded or brazed together.

  Here, since the tip portion of the inner tube and the connecting tube, and the tip portion of the inner tube and the pipe expansion receiving portion are collectively welded or brazed together, they can be joined with good sealing performance. In addition, since the work that has been conventionally performed at two locations can be performed simultaneously, the joining process can be shortened, and the joining work can be performed quickly and reliably.

  A heat exchange unit according to a third aspect of the present invention is the heat exchange unit according to the first or second aspect of the present invention, wherein the end portion of the distal end portion of the inner tube protrudes beyond the distal end of the tube expansion receiving portion.

  Here, since the end portion of the distal end portion of the inner tube protrudes outward from the distal end of the tube expansion receiving portion, welding or brazing is easy.

  The heat exchange unit according to a fourth aspect of the present invention is the heat exchange unit according to the third aspect of the present invention, wherein the length of the portion of the inner tube that goes out of the expanded tube receiving portion is 0.5 to 3 mm.

  Here, since the length of the portion of the inner tube that goes out of the expanded tube receiving portion is 0.5 to 3 mm, it is easier to weld or braze the inner tube.

  A heat exchange unit according to a fifth aspect of the present invention is the heat exchange unit according to any one of the first to fourth aspects of the present invention, wherein the inner diameter of the tube expansion receiving portion is larger than the inner diameter of the through hole.

  Here, since the inner diameter of the tube receiving portion is larger than the inner diameter of the through hole, it is easy to expand the tip portion of the inner tube and constriction easily occurs.

  A heat exchange unit according to a sixth aspect of the present invention is the heat exchange unit according to any one of the first to fifth aspects of the present invention, wherein the tube expansion receiving portion is a thin tube that is thinner than the thickness of the wall around the space portion of the header. It is a shaped part.

  Here, since the pipe expansion receiving portion is a tubular portion having a thickness smaller than the thickness of the wall around the space portion of the header, welding and brazing are facilitated by making the pipe expansion receiving portion thinner.

  A heat exchange unit according to a seventh aspect is the heat exchange unit according to any one of the first to sixth aspects, wherein the heat exchanger is formed by extruding the inner tube and the outer tube integrally. It is manufactured by.

  Here, since the heat exchanger is manufactured by integrating the inner tube and the outer tube and extrusion molding, the heat exchanger can be easily manufactured. In addition, by adopting an extrudable material, it is easy to expand the inner tube.

  According to the first aspect of the present invention, the tip portion of the inner tube of the heat exchanger is expanded and is in close contact with the inner surface of the expanded tube receiving portion. Therefore, the joint portion between the inner tube and the header and the inner tube and the external connection tube The leakage of the refrigerant can be prevented and the pressure resistance can be improved at the joint between the two.

  According to the second invention, bonding can be performed with good sealing properties. And since the operation | work conventionally performed separately at two places can be performed simultaneously, a joining process can be shortened and a joining operation can be performed rapidly and reliably.

  According to the third invention, welding or brazing is easy.

  According to the fourth invention, it is easier to weld or braze the inner tube.

  According to the fifth aspect of the invention, it is easy to expand the tip portion of the inner tube, and constriction is likely to occur.

  According to the sixth aspect of the present invention, welding and brazing are facilitated by thinning the pipe expansion receiving portion.

  According to the seventh invention, the heat exchanger can be easily manufactured. In addition, by adopting an extrudable material, it is easy to expand the inner tube.

Sectional drawing of the heat exchange unit concerning embodiment of this invention. The expansion perspective view in the edge part vicinity of the heat exchanger of FIG. The front view of the edge part of the heat exchanger of FIG. Cross-sectional explanatory drawing which shows the manufacturing process of the heat exchange unit of FIG. Cross-sectional explanatory drawing which shows the manufacturing process of the heat exchange unit of FIG. Cross-sectional explanatory drawing which shows the manufacturing process of the heat exchange unit of FIG. Sectional drawing of the conventional heat exchange unit which is a comparative example of this invention.

Next, an embodiment of the heat exchange unit of the present invention will be described with reference to the drawings.
Embodiment
A heat exchange unit 1 shown in FIG. 1 includes a double-pipe heat exchanger 2 and a header 3. In addition, a first connection pipe 4 and a second connection pipe 5 are connected to the heat exchange unit 1.

  As shown in FIGS. 1 to 3, the heat exchanger 2 has a double tube structure having an inner tube 6 and an outer tube 7 disposed on the outer periphery of the inner tube 6. The inner tube 6 is longer than the outer tube 7.

  In addition, two refrigerant channels, that is, a first channel 8 and a second channel 9 are formed in the heat exchanger 2. The first flow path 8 is formed inside the inner tube 6 so as to extend in the longitudinal direction of the inner tube 6. A plurality of second flow paths 9 are formed in parallel around each other around the inner tube 6 so as to extend in the longitudinal direction of the inner tube 6 between the inner tube 6 and the outer tube 7.

  The heat exchanger 2 is manufactured by integrating the inner tube 6 and the outer tube 7 using a material such as aluminum, and is easy to manufacture.

  In addition, when forming the front-end | tip part 16 of the inner tube | pipe 6 which protrudes from the outer tube | pipe 7, for example, after the inner tube | pipe 6 and the outer tube | pipe 7 are integrated and extrusion-molded, the edge part vicinity of the outer tube | pipe 7 is cut. It is formed by removing the tip portion 16 of the inner pipe 6 by processing.

  As shown in FIG. 1, the header 3 has a space 10 that communicates with the second flow path 9 connected to the end of the outer tube 7. In addition, a through hole 11 is formed in the wall of the header 3 so that the distal end portion 16 of the inner tube 6 passes through the space portion 10. The header 3 is made of, for example, an aluminum alloy.

  Further, around the through hole 11 on the outer surface of the header 3, a tube expansion receiving portion having an inner diameter (D2) larger than the outer diameter of the inner tube 6 inside the space portion 10 (size of the inner diameter D1 or less of the through hole 11). 13 is provided.

  Of the distal end portion 16 of the inner tube 6, a portion 17 that goes out of the space portion 10 through the through hole 11 is in close contact with the inner surface of the tube expansion receiving portion 13 by being expanded. Therefore, at the joint part between the inner pipe 6 and the header 3 and the joint part between the inner pipe 6 and the external first connection pipe 4, a structure in which refrigerant leakage is prevented and the pressure strength is improved. ing.

  Further, in the heat exchange unit 1 of FIG. 1, the first connection pipe 4 is inserted from the outside into the expanded portion 17 at the distal end portion of the inner pipe 6. And between the front-end | tip part 16 of the inner tube 6 and the 1st connection pipe 4, and between the front-end | tip part 16 of the inner tube 6 and the pipe expansion receiving part 13 are collectively welded or brazed together. This welded or brazed portion is indicated at 21 in FIG.

  Further, as shown in FIG. 1, other joint portions are similarly welded or brazed, and specifically, a welded or brazed portion is provided between the header 3 and the outer tube 7 of the heat exchanger 2. 22, and the header 3 and the second connection pipe 5 are joined by a welded or brazed portion 23.

  Further, as shown in FIG. 1, the end portion 16a of the distal end portion 16 of the inner tube 6 protrudes outward from the distal end of the expanded tube receiving portion 13, and the inner tube 6 can be easily welded or brazed. Yes.

  In particular, since the length L1 of the portion 16a of the inner tube 6 that goes out of the tube receiving portion 13 is 0.5 to 3 mm, it is easier to weld or braze the inner tube 6.

  Here, if the length L1 is less than 0.5 mm, the contact area between the portion 16a and the welded or brazed portion becomes small, so that welding or brazing becomes difficult and joint strength and sealability are reduced, On the other hand, if the length L1 exceeds 3 mm, it becomes impossible to weld or braze together with the first connecting pipe 4 and the pipe expansion receiving portion 13. Therefore, if the length L1 is in the range of 0.5 to 3 mm, the inner tube 6 can be easily welded or brazed together with the first connecting tube 4 and the expanded tube receiving portion 13, and the bonding strength and sealing performance are improved. high.

  Moreover, the inner diameter D1 of the pipe expansion receiving portion 13 is larger than the inner diameter D2 of the through hole 11, and the pipe expansion is easy.

Furthermore, as shown in FIG. 4, the tube expansion receiving portion 13 is a tubular portion having a thickness T2 that is thinner than the thickness T1 of the wall 14 around the space portion 10 of the header 3. A portion of the tube expansion receiving portion 13 is partially thin.
<Method for Manufacturing Heat Exchange Unit 1>
Below, the manufacturing method of the heat exchange unit 1 of this embodiment is demonstrated in order of each process shown by FIGS.

  First, as shown in FIGS. 4 to 5, the heat exchanger 2 manufactured by extruding and integrally forming aluminum or the like is inserted into the space 10 inside the header 3. At this time, as shown in FIG. 5, the outer peripheral surface of the outer tube 7 is fitted to the inner wall of the header 3, and a part of the distal end portion 16 of the inner tube 6 passes through the through hole 11 of the header 3. It will be in the state where it goes out of.

  Next, as shown in FIG. 6, the tube expansion head E having a taper Te is press-fitted into a portion 17 of the distal end portion 16 of the inner tube 6 that has come out of the space portion 10 through the through hole 11. Expand the pipe.

  At this time, a portion 17 of the distal end portion 16 of the inner tube 6 that has come out of the space portion 10 through the through hole 11 is in close contact with the inner surface of the tube expansion receiving portion 13 by being expanded.

  In addition, it is preferable to clamp and fix the heat exchanger 2 and the header 3 at the time of pipe expansion.

  Thereafter, as shown in FIG. 1, welding or brazing is performed at three locations.

  First, the heat exchanger 2 and the header 3 are welded or brazed at the welded or brazed portion 22.

  Next, after the first connecting pipe 4 is inserted into the expanded portion 17 of the distal end portion 16 of the inner tube 6, the first connecting tube 4, the portion 17 of the heat exchanger 2, The pipe expansion receiving portions 13 of the header 3 are collectively welded or brazed together.

Finally, as shown in FIG. 1, after the second connecting pipe 5 is inserted into the through hole 12 of the header 3, the second connecting pipe 5 and the header 3 are welded or brazed at the welded or brazed portion 23. Then, the manufacture of the heat exchange unit 1 is completed.
<Comparison with comparative examples>
For example, in a conventional heat exchange unit 101 shown in FIG. 7 as a comparative example of the present invention, a heat exchanger 102 having an inner tube 106 and an outer tube 107 is joined to the header 103, and a distal end portion 116 of the inner tube 106. Of these, the portion 117 that protrudes out of the space 110 from the through hole 111 of the header 103 has a structure in which the connecting pipe 104 is fitted so as to cover the outside of the portion 117 without being expanded. That is, the header 103 does not have a portion corresponding to the tube expansion receiving portion 13 shown in FIG. 1 as shown in FIG. 1, and the tip of the inner tube 106 is not expanded.

In such a structure, the distal end portion 116 of the inner tube 106 and the header 103 are joined by welding or brazing portion 121, and separately, the distal end portion 116 of the inner tube 106 and the first connection tube 104 are joined together. It is necessary to join between them by welding or brazing part 124. For this reason, the joint portion dispersed in two places has poor sealing properties, and the pressure strength may be insufficient. Moreover, it is impossible to perform the joining work quickly and reliably.
<Features>
(1)
In the heat exchange unit 1 of the embodiment, a tube expansion receiving portion 13 having an inner diameter larger than the outer diameter of the inner tube 6 inside the space portion 10 is provided around the through hole 11 on the outer surface of the header 3. And the part 17 which went out of the space part 10 through the through-hole 11 among the front-end | tip parts 16 of the inner tube 6 is closely_contact | adhered to the inner surface of the pipe expansion receiving part 13 by being expanded.

In this way, since the distal end portion 16 of the inner tube 6 is in close contact with the header 3 by being expanded, the joint portion between the inner tube 6 and the header 3 and the inner tube 6 and the external first connecting tube 4 are arranged. The leakage of the refrigerant can be prevented and the pressure resistance is improved at the joint between the two.
(2)
Further, in this embodiment, the portion of the inner tube 6 at the end of the double-tube heat exchanger 2 extruded with aluminum is less than the header 3, and the outer tube 6 is outside the inner tube 6. Since the strength of the exiting portion is maintained by the first connecting pipe 4, the lack of pressure strength can be solved.
(3)
Further, in the heat exchange unit 1 of the embodiment, the first connecting pipe 4 is inserted from the outside into the expanded portion 17 at the distal end portion of the inner pipe 6. And between the front-end | tip part 16 of the inner tube 6, and the 1st connection pipe 4, and between the front-end | tip part 16 of the inner tube 6, and the pipe expansion receiving part 13, it is the site | part of the welding or brazing part 21 collectively. , Welded or brazed.

  As described above, the three portions of the tip portion 16 of the inner tube 6, the first connection tube 4, and the pipe expansion receiving portion 13 can be welded or brazed at the same time so that they can be joined with good sealing performance. In addition, since the work that has been conventionally performed at two locations can be performed simultaneously, the joining process can be shortened, and the joining work can be performed quickly and reliably.

Moreover, when visually confirming from the outside after joining, since the two joining locations can be easily confirmed from one direction, it is possible to prevent joining failure due to refrigerant leakage.
(4)
Furthermore, in the heat exchange unit 1 of the embodiment, the end portion 16a of the distal end portion 16 of the inner tube 6 protrudes more outward than the distal end of the expanded tube receiving portion 13, so that it is easy to braze the inner tube 6 or the like. ing.
(5)
In particular, in the heat exchange unit 1 of the embodiment, since the length of the portion 16a of the inner tube 6 that goes out of the tube receiving portion 13 is 0.5 to 3 mm, the inner tube 6 is welded or brazed. Is easier. That is, if the length L1 is in the range of 0.5 to 3 mm, the inner tube 6 can be easily welded or brazed together with the first connecting tube 4 and the expanded tube receiving portion 13, and the bonding strength and sealing performance are high. high.
(6)
Further, in the heat exchange unit 1 of the embodiment, the inner diameter D1 of the tube expansion receiving portion 13 is larger than the inner diameter D2 of the through hole 11, so that the distal end portion 16 of the inner tube 6 can be easily expanded and constriction easily occurs. ing.
(7)
Furthermore, in the heat exchange unit 1 of the embodiment, the tube expansion receiving portion 13 is a cylindrical portion having a thickness T2 that is thinner than the thickness T1 of the wall 14 around the space portion 10 of the header 3 (see FIG. 4). Such a shape facilitates welding and brazing by reducing the thickness of the pipe expansion receiving portion 13.

In addition, even if the pipe expansion receiving part 13 is formed into a thin cylindrical shape, the first connecting pipe 4 is inserted into the pipe expansion receiving part 13 and the strength is maintained.
(8)
Moreover, in the heat exchange unit 1 of the embodiment, the heat exchanger 2 is manufactured by integrating and molding the inner tube 6 and the outer tube 7 using a material such as aluminum.

Thus, the heat exchanger 2 can be easily manufactured by extrusion-molding and manufacturing the heat exchanger 2 using a material such as aluminum. In addition, by adopting an extrudable material, it is easy to expand the inner tube 6.
<Modification>
(A)
In the heat exchange unit 1 of the embodiment, the cylindrical tube receiving portion 13 is thinner and smaller in outer shape than the header 3, but the present invention is not limited to this, and is the same as the thickness of the header 3. You may use the pipe expansion receiving part 13 of the wall thickness of a grade or more.

  The present invention can be applied to various heat exchange units as long as the heat exchange unit includes a double-pipe heat exchanger having an inner tube and an outer tube.

  For example, the present invention can be suitably applied to a heat exchange unit used as a heat exchanger of an economizer circuit for improving the efficiency of a CO 2 refrigeration cycle for an air conditioner / water heater.

  Moreover, it can be suitably applied to a heat exchange unit used as a liquid gas heat exchanger (internal heat exchanger) for improving the efficiency of the CO 2 refrigeration cycle.

  Furthermore, the present invention can also be suitably applied to a liquid gas heat exchanger for HFC, a cascade heat exchanger for HFC-CO2 or HFC-HFC. In this case, the high temperature side fluid is condensed, but the present invention may be used to remove the condensed liquid from the heat transfer surface.

  Further, the present invention can also be suitably applied to a heat exchanger for water-refrigerant heat exchange that is used by circulating water inside and refrigerant outside.

DESCRIPTION OF SYMBOLS 1 Heat exchange unit 2 Heat exchanger 3 Header 6 Inner pipe 7 Outer pipe 10 Space part 11 Through-hole 13 Pipe expansion receiving part 16 Tip part 17 Parts 21, 22, and 23 which went out of the space part Welding or brazing part

JP 2008-175449 A

Claims (7)

A heat exchanger (2) having an inner tube (6) and an outer tube (7) disposed on the outer periphery of the inner tube (6), wherein the inner tube (6) is the outer tube (7). A first flow path (8) extending in the longitudinal direction of the inner pipe (6) is formed inside the inner pipe (6), and is formed between the inner pipe (6) and the outer pipe (7). A heat exchanger (2) formed with a second flow path (9) extending in the longitudinal direction of the inner pipe (6),
A header (3) connected to an end of the outer pipe (7), having a space (10) communicating with the second flow path (9), and a tip portion of the inner pipe (6) A header (3) formed with a through hole (11) through which (16) passes and goes out of the space (10);
Around the through hole (11) on the outer surface of the header (3), there is provided a tube expansion receiving portion (13) having an inner diameter larger than the outer diameter of the inner tube (6) inside the space portion (10). And
Of the distal end portion (16) of the inner tube (6), the portion (17) that goes out of the space portion (10) through the through-hole (11) is expanded, whereby the expanded tube receiving portion (13). )
Heat exchange unit (1). A connecting pipe (4) is inserted from the outside into the expanded part of the tip part (16) of the inner pipe (6),
Between the tip portion (16) of the inner tube (6) and the connecting tube (4) and between the tip portion (16) of the inner tube (6) and the tube expansion receiving portion (13) Simultaneously welded or brazed,
The heat exchange unit (1) according to claim 1. An end portion of the distal end portion (16) of the inner tube (6) protrudes outward from a distal end of the tube expansion receiving portion (13).
The heat exchange unit (1) according to claim 1 or 2. Of the inner tube (6), the length (L1) of the portion (16a) that has gone out of the tube expansion receiving portion (13) is 0.5 to 3 mm.
The heat exchange unit (1) according to claim 3. The inner diameter of the tube expansion receiving part (13) is larger than the inner diameter of the through hole (11).
The heat exchange unit (1) according to any one of claims 1 to 4. The tube expansion receiving portion (13) is a tubular portion having a wall thickness that is thinner than the thickness of the wall around the space portion (10) of the header (3).
The heat exchange unit (1) according to any one of claims 1 to 5. The heat exchanger (2) is manufactured by integrating and molding the inner pipe (6) and the outer pipe (7).
The heat exchange unit (1) according to any one of claims 1 to 6.

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