JP2007101041A - Water heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact easy-to-manufacture carbon dioxide refrigerant-water heat exchanger with a comparatively simple structure improving heat exchange performance by increasing a heat transfer surface area without elongating a tube length. <P>SOLUTION: A cylindrical part 13 is provided by using four inner tubes 12a, 12b, 12c, 12d provided with hairpin shaped parts 32a-32d by bending middle portions in a length direction 180 degrees, and by arranging the inner tubes 12a-12d such that straight parts are in close contact with each other on the same circumference. In a cylindrical inner tube group 11, gaps 20 are formed between adjacent hairpin shaped parts 32a-32d by arranging the hairpin shaped parts 32a-32d such that they are respectively deviated in axial directions, and the cylindrical inner tube group 11 is housed in an outer tube 14 with a large diameter and one end 16 sealed, to compose the water heat exchanger 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water heat exchanger for exchanging heat between a heat exchange medium and water, and more particularly to a water heat exchanger for exchanging heat between a refrigerant mainly composed of carbon dioxide gas and water. is there.

  Conventionally, as a heat exchanger for a hot water heater, for example, a double-tube heat transfer tube in which an inner tube is arranged inside an outer tube is used to circulate water in the inner tube, while the inner tube and the outer tube Various types of water heat exchangers have been used in which heat is exchanged between water and the refrigerant by causing the refrigerant to flow in a counterflow in the gap therebetween.

  As a heat exchange medium (refrigerant) used in such a water heat exchanger, a natural refrigerant having a low global warming coefficient is used in place of the conventional chlorofluorocarbon refrigerant from the viewpoint of ozone layer protection and global warming prevention. In recent years, heat exchangers (heat pumps) using this natural refrigerant have been developed. Further, among such natural refrigerants, particularly when carbon dioxide is used, gas conditions of high temperature and high pressure can be obtained, so that it can be heated to 75 ° C. to 90 ° C. only with a single stage heat exchanger. It has a special feature and is attracting particular attention.

  By the way, as shown in Patent Documents 1 to 4, various types of heat exchangers that exchange heat between the refrigerant mainly composed of carbon dioxide and water are proposed. In order to increase the heat exchange efficiency, for example, in Japanese Patent Application Laid-Open No. 2003-214778 (Patent Document 1), along the axial direction of the peripheral wall of the first heat exchange pipe through which the heat exchange liquid flows. A second heat exchange pipe through which a predetermined heat medium flows is disposed, and the first heat exchange pipe and the second heat exchange pipe are brazed and integrated. As a result, the heat of the heat medium flowing in the second heat exchange pipe is efficiently transferred to the heat exchange liquid flowing in the first heat exchange pipe via the brazing material without causing a gap between them. It is clear that what is being heat exchanged To have.

  However, those heat exchangers, for example, those disclosed in Patent Document 1, have a relatively simple structure, so that the size of the heat exchanger can be easily reduced, but the refrigerant as the heat medium is The contact area between the second heat exchange pipe that circulates and the first heat exchange pipe that circulates the water that is the heat exchange liquid is not sufficient, and the second heat exchange pipe that allows the refrigerant to circulate is external. Therefore, the heat dissipation from the pipe is increased and the heat exchange rate is lowered. In addition, since the contact portion between the first heat exchange pipe and the second heat exchange pipe is joined by brazing, it takes time to manufacture and there is a possibility that productivity may be reduced. .

  In addition, the inner tube is inserted concentrically into the outer tube, and the inner tube is used as a water flow path, while the space between the inner tube and the outer pipe is used as a refrigerant flow path. In order to improve the heat exchange performance of the vessel, a method of expanding the heat transfer area by providing spiral grooves and fins on the inner and outer surfaces of the inner tube will be adopted. There is a limit to the performance improvement by the method, so it is necessary to lengthen the tube length for a significant performance improvement, and as a result, the problem that the compactness of the heat exchanger must be sacrificed Met.

  Furthermore, like what is disclosed in Patent Document 2, the flow length and flow velocity are increased by the provision of a heat transfer promoting body, and further heat exchange performance is improved by turbulence, or Patent Document 3, 4 reveals the effect of forming a swirling flow by a twisted tape formed by twisting a flat plate or increasing the contact area between the refrigerant and the refrigerant tube using a large number of fine refrigerant tubes. However, they have a problem that the heat exchange performance from the refrigerant to water is not sufficiently improved because the contact area between the refrigerant and the water to be heat exchanged is not sufficient.

JP 2003-214778 A JP 2001-201275 A Japanese Patent Application Laid-Open No. 2004-257691 JP 2002-122390 A

Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to improve the heat exchange performance by increasing the heat transfer area without increasing the tube length. Another object of the present invention is to provide a water heat exchanger, particularly a CO ₂ water heat exchanger, which is easy to manufacture with a relatively simple structure.

  In the present invention, in order to solve the above-described problems, one end is closed, a large-diameter outer tube through which water to be heat exchanged is circulated, and an intermediate portion is formed into a hairpin shape. The heat exchange medium introduced from one end side is configured by combining a plurality of small inner pipes that are guided to the other end side by changing the flow direction by 180 °. A cylindrical inner tube group in which the hairpin-shaped portion of the inner tube is positioned on the closed end side of the outer tube, and the cylindrical inner tube group closely contacts the straight portion of each inner tube on the same circumference. And at the tip of the cylindrical inner tube group, a gap is formed between the hairpin-shaped portions of the inner tubes, and the cylindrical inner tubes The inside and outside of the group are communicated, and the water to be heat exchanged is passed through the gap inside the outer pipe. The water heat exchanger, characterized in that is adapted to be caused to flow from one to the other of the outer and inner Oite cylindrical inner tube group is for its gist.

  Moreover, according to one of the desirable aspects of the water heat exchanger according to the present invention, the hairpin-shaped portion of each inner tube constituting the cylindrical inner tube group is displaced in the axial direction of the cylindrical portion. According to one of the other desirable embodiments, the straight portion of each inner tube constituting the cylindrical portion of the cylindrical inner tube group is formed on the inlet side of the heat exchange medium. The straight portions and the straight portions on the exit side are arranged so as to be alternately located in the circumferential direction.

  Furthermore, according to one of the preferable aspects of the water heat exchanger according to the present invention, the water to be heat-exchanged is configured to flow from the outside to the inside of the cylindrical inner tube group in the outer tube. Has been.

  Furthermore, according to another preferable aspect of the present invention, a refrigerant mainly composed of carbon dioxide gas is used as the heat exchange medium.

  Thus, according to the water heat exchanger according to the present invention, a plurality of hairpin-shaped inner pipes are combined to bring the outer peripheral surfaces of the straight portions of adjacent inner pipes into contact with each other so that there is no gap. The cylindrical inner tube group arranged in the shape of a tube is arranged in the outer tube having a large diameter, so that the inner peripheral surface of the outer tube and the outer peripheral surface of the cylindrical inner tube group and the cylindrical inner tube are arranged. The passages are formed inside the group so that water can be circulated from one of them to the other, so that the heat transfer area between the refrigerant and water can be increased without increasing the overall pipe length. Therefore, it is possible to effectively increase the heat exchange efficiency of the water heat exchanger by advantageously exchanging heat between the refrigerant and water. It becomes possible.

  Moreover, according to one of the desirable aspects of the water heat exchanger according to the present invention, when combining the straight portions of the plurality of hairpin-shaped inner tubes into a cylindrical body, the axial direction of the cylindrical body At the portion of the end (tip) where multiple hairpin-shaped portions overlap, the inner and outer sides of the tubular body can be inserted only by shifting the hairpin-shaped portion of each inner tube in the axial direction. Since the gap is formed at the tip portion of such a cylindrical body, there is no need to perform special processing for forming the passage, and this advantageously improves the manufacturability of the water heat exchanger. It becomes possible to improve.

  Furthermore, in another desirable aspect of the water heat exchanger according to the present invention, in the inner tube group cylindrical portion formed by the straight portions of the plurality of inner tubes, heat exchange is allowed to circulate in each inner tube. Since the straight portion on the inlet side and the straight portion on the outlet side are alternately arranged in the circumferential direction of the medium, the inner pipe through which the high-temperature refrigerant is circulated does not concentrate on a part. Therefore, heat exchange can be performed uniformly, and heat exchange efficiency can be improved.

  Furthermore, according to one of the preferable embodiments of the water heat exchanger according to the present invention, the tubular portion of the tubular inner tube group is formed from the flow path formed between the tubular inner tube group and the outer tube. The water heated by the high-temperature heat exchange medium circulated in the inner pipe from where the heat exchanged water is allowed to flow toward the inner flow path is formed into a cylindrical shape. By being distributed inside the inner tube group, it is further heated, so that heat can be effectively transferred from the heat exchange medium to water. On the other hand, when passing from the inside to the outside of the cylindrical inner tube group, the water heated by the heat exchange with the refrigerant passes through the flow path outside the cylindrical inner tube group. The amount of heat dissipated outside through the wall of the outer tube increases, and the thermal efficiency decreases.

  In addition, according to another preferred embodiment of the water heat exchanger according to the present invention, water is sufficiently heated by carbon dioxide gas at high temperature and pressure by using a refrigerant mainly composed of carbon dioxide gas as a heat exchange medium. In addition, since the global warming potential is lower than that of conventional chlorofluorocarbon refrigerants, the risk of environmental destruction can be effectively eliminated.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows an embodiment of a water heat exchanger according to the present invention in the form of a cross-sectional view with a part thereof cut away. In this case, the water heat exchanger 10 includes a cylindrical inner tube group 11 formed by combining a plurality of small inner tubes (12a to 12d), and a bottomed cylindrical shape in which one end portion 16 is sealed. Are accommodated in a large-diameter outer tube 14.

  More specifically, the cylindrical inner tube group 11 is composed of four tubes of inner tubes 12a, 12b, 12c, and 12d. The inner pipes 12a to 12d are thin linear transmissions made of a predetermined metal material appropriately selected from copper, copper alloy, or the like according to required heat transfer performance. Each is formed in a form in which hairpin-shaped portions 32a to 32d are provided by using a heat tube and bending it 180 ° at the central portion in the longitudinal direction. Moreover, as shown in FIG. 2 (b), the inner pipes 12a to 12d having such a form are positioned on the same circumference with straight portions located on both sides in the axial direction of the respective hairpin-shaped portions 32a to 32d. Thus, the cylindrical portion 13 of the cylindrical inner tube group 11 is formed by being arranged so as to form a ring as a whole.

  Further, here, as shown in FIG. 2 (a), such inner tubes 12a to 12d are arranged such that adjacent ones thereof are arranged with a phase difference of 45 degrees in the circumferential direction, respectively. In combination, the cylindrical portion 13 of the cylindrical inner tube group 11 is formed, and the hairpin-shaped portions 32a to 32d of the inner tubes 12a to 12d are respectively displaced in the axial direction and arranged. Thus, a gap 20 is formed between adjacent ones of the hairpin shape portions 32a to 32d, for example, between the hairpin shape portion 32a and the hairpin shape portion 32b, and the inside and outside of the tubular inner tube group 11 However, in the front end side part, it communicates by such a gap 20.

  The cylindrical inner tube group 11 formed in this way is formed of a predetermined metal material, and the hairpin-shaped portion 32a is formed in the bottomed cylindrical outer tube 14 whose one end portion 16 is sealed. The gap formed between the inner peripheral surface of the outer tube 14 and the outer peripheral surface of the cylindrical inner tube group 11 by being inserted so as to be on the sealed end portion 16 side on the 32d side. However, it becomes the flow path 26 through which the water to be heat-exchanged is circulated. In addition, such a flow path 26 is between the above-mentioned hairpin shape parts 32a-32d in the flow path 28 formed in the internal space formed inside the cylindrical inner pipe group 11 which consists of the inner pipes 12a-12d. It is made to communicate through the clearance gap 20 formed in this.

  A lid member 18 is attached to the end of the outer cylinder 14 opposite to the sealed end 16 side so as to seal the outer tube 14. And this lid member 18 is attached to and supported by the ends of the cylindrical inner tube group 11 (inner tubes 12a to 12d) opposite to the hairpin-shaped portions 32a to 32d in the axial direction. The outer side and the inner side (flow path 26 and flow path 28) of the inner pipe group 11 are separated so as not to communicate with each other on the lid member 18 side, and intakes on one end side of the inner pipes 12a to 12d are provided. And the outlet on the other end side are respectively connected to an inlet 22a and an outlet 22b provided in the lid member 18, which serve as one assembled inlet and outlet.

  Further, the outer cylinder 14 is provided with a water inlet 24a in the vicinity of the end portion closed by the lid member 18, and is introduced into the outer cylinder 14 (channel 26) from the water inlet 24a. The water thus circulated in the inner pipes 12a to 12d while flowing in the axial direction in the flow path 26 between the outer cylinder 14 and the inner pipes 12a to 12d group from the lid member 18 side to the sealed end 16 side. Heat exchange is performed with a heat transfer medium that is a heat exchange medium, for example, a carbon dioxide refrigerant. Then, the water that has reached the sealed end portion 16 side of the outer tube 14 flows into the cylindrical inner tube group 11, that is, into the flow channel 28 through the gap 20, and the flow channel 28 is moved from the hairpin shape portion 32 side. Heat exchange is further performed with the heat transfer medium that is circulated toward the lid member 18 and circulates in the inner pipes 12a to 12d. Water sufficiently heat-exchanged in this way is supplied from the water intake 24b provided in the lid member 18 so as to conduct the inside of the cylindrical inner tube group 11 by the inner tubes 12a to 12d, that is, the flow path 28 and the outside. It is taken out of the heat exchanger 10. Of course, it is possible to circulate water in the direction opposite to the flow of water, that is, by introducing water from the water intake port 24b and flowing the water to the water inlet port 24a. When the water passes through the outer flow path 26, the amount of heat exchanged from the outer surface of the outer tube 14 is increased, which may deteriorate the thermal efficiency. Therefore, as in the present embodiment, low temperature water can be circulated through the outer flow path 26, and high temperature water can be circulated through the inner flow path 28. It is desirable.

  By the way, such a water heat exchanger 10 is manufactured in the following processes, for example. That is, first, a plurality of linear heat transfer tubes formed of appropriately selected metal materials are used, and the hairpin shape portions 32a to 32d are formed by bending a substantially central portion in the length direction by 180 degrees. Then, hairpin-shaped inner tubes 12a to 12d as shown in FIG. Next, using these inner tubes 12a to 12d (four), as shown in FIG. 3B, the straight portions 30a to 30d are arranged and combined to form a cylindrical shape, and the inner tubes 12a to 12d are combined. A cylindrical inner tube group 11 made of 12d is formed. At this time, preferably, an appropriate core material is used, the inner pipes 12a to 12d are arranged around the core material to form a cylindrical shape, and then drawing is performed from the outside, and such drawing processing is performed. If such a core material is later removed from the inside of the cylinder, the outer peripheral surfaces of the inner pipes 12a to 12d are more effectively brought into contact with each other. When the inner pipes 12a to 12d are combined to form a cylindrical shape in this way, the hairpin-shaped part of the inner pipe displaced in the axial direction and the straight part of another inner pipe intersect with each other. In such an interference location, for example, in the straight portion side or the hairpin shape portion, there is a risk of interference at the location, such a location may bulge to the outside, and a gap may occur in the cylindrical outer wall portion. The inner tube is deformed so as to crush one of the inner tubes or both of the inner tubes, so that the inner tubes are brought into close contact with each other, and a gap is not formed in the outer wall of the cylindrical inner tube group 11. It will be.

  Thereafter, the lid member 18 is attached to the end side where the openings of the inner pipes 12a to 12d are collected on the side opposite to the hairpin shape part 32a to 32d side of the cylindrical inner pipe group 11 in the axial direction. Of the openings of the inner pipes 12a to 12d, the opening on the heat transfer medium take-in side and the opening on the heat transfer medium take-out side are gathered together to form a lid. They are connected to an inlet 22a and an outlet 22b provided in the member 18 (see FIG. 3C).

  In this way, the cylindrical inner tube group 11 attached to the lid member 18 is sealed in the outer tube 14 in which one end portion 16 is integrally sealed, and the hairpin-shaped portions 32a to 32d are sealed. The outer tube is inserted so as to be on the end portion 16 side, and the opening portion on the opposite side to the sealing end portion 16 side of the outer tube 14 is attached so as to cover with the lid member 18. 14 is sealed, and the water heat exchanger 10 is completed as shown in FIG.

  Thus, according to the water heat exchanger 10 according to the present invention, the hairpin-shaped portions 32a to 32d are provided in the inner tubes 12a to 12d through which the heat transfer medium is circulated, and the flow direction of the heat transfer medium is changed. The cylindrical inner tube group 11 formed by a plurality of the inner pins 12a to 12d having such a hairpin shape is rotated 180 degrees so that the hairpin shape portions 32a to 32d side becomes the sealed end portion 16 side. The water which is inserted into the outer tube 14 and exchanges heat in the outer tube 14 flows into the flow path 26 formed between the inner peripheral surface of the outer tube 14 and the outer peripheral surface of the cylindrical inner tube group 11. In addition, since it also passes through the flow path 28 inside the cylindrical inner tube group 11, the heat transfer medium circulated through the inner tubes 12 a to 12 d and the water to be heat-exchanged are exchanged. Increase the length of the outer tube 14 through which the water can flow through the heat transfer area. Rukoto no advantage can allowed to increase, than Te, the heat exchange efficiency between the water and the heat exchange medium (refrigerant) is become possible allowed to effectively improve. And since a high heat exchange efficiency can be exhibited without increasing the tube length of the outer tube 14 in this way, a more compact water heat exchanger can be obtained.

  Furthermore, in such a water heat exchanger 10, the inner tubes 12a to 12d, which are simply heat-transfer tubes having a hairpin shape, are combined so that their straight portions 30a to 30d have a tubular shape, and the tubular inner tube The group 11 and the cylindrical inner tube group 11 are accommodated in the outer tube 14 and formed into a relatively simple structure, so that the productivity is effectively improved. It can also be done.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the above embodiment, four inner pipes 12a to 12d are combined in a state where adjacent inner pipes are rotated and moved 45 degrees in the circumferential direction as shown in FIG. Although the cylindrical portion 13 is formed by 30a to 30d, as shown in FIGS. 4 (a) to (c), inner tubes 34a and 34b and two inner tubes 34a and 34b formed by combining two inner tubes each having a hairpin shape. The pipes 34c and 34d may be rotated 90 degrees in the circumferential direction to form a cylindrical shape by the group of the inner pipes 34a to 34d. Thus, in the case where the inner pipes 34a to 34d are combined to form a cylindrical shape, the flow direction of the refrigerant (heat transfer medium) is, for example, one of the straight portions 34aa and 34ba of the inner pipes 34a to 34d. , 34ca, 34da are the refrigerant going side (refrigerant entry side), the other straight portions 34ab, 34bb, 34cb, 34db are the refrigerant return side (refrigerant exit side), and the direction in which the refrigerant flows is adjacent. Since the matching inner pipes are alternately arranged, the inner pipes through which the high-temperature refrigerant is circulated do not concentrate on a part of the cylindrical wall of the cylindrical body by the inner pipes 34a to 34d group, Since uniform heat exchange can be performed between water and the refrigerant, heat exchange efficiency can be further improved.

  Further, the number of such inner pipes is not limited to four shown in the above-described embodiment, but may be combined with five, six, or more pipes as shown in FIG. 5 and FIG. It is of course possible to form a group and form a cylindrical shape with the inner tube group.

  For example, as shown in FIGS. 5 (a) and 5 (b), five inner pipes 36a to 36e are arranged so that adjacent inner pipes are spirally shaped so that the hairpin-shaped parts (bending parts) are spiral. In the straight portion, a cylindrical body is formed by a group of inner pipes 36a to 36e by being combined so as to be rotated and positioned by a predetermined angle in the circumferential direction, or as shown in FIGS. 6 (a) and 6 (b). The six inner pipes 38a to 38f are combined in the same manner as in FIG. 5 so that the adjacent inner pipes are rotated by 30 degrees in the circumferential direction of the cylindrical body. May be formed.

  Further, as shown in FIGS. 7A and 7B, the six inner pipes 38a to 38f are combined with two inner pipes, and rotated in the circumferential direction by 60 degrees respectively. By combining them, it is possible to form a cylindrical inner tube group. When the inner pipes 38a to 38f have such a combination, the flow direction of the refrigerant is alternately arranged between the adjacent inner pipes in the same manner as that shown in FIG. 4 described above. Therefore, the heat exchange rate can be advantageously improved.

  In addition, how to combine these inner pipes 12a to 12d (34a to 34d, 36a to 36e, 38a to 38f) is appropriately selected and used according to manufacturability and required heat exchange performance. .

  Furthermore, one end 16 of the outer tube 14 may be closed by a removable lid member in addition to the one integrally sealed with the outer tube 14 as in the above-described embodiment. As described above, when the water heat exchanger 10 is used by sealing with a removable lid member, silica or the like contained in the water to be heat exchanged (tap water, etc.) is deposited, and the scale When this occurs, the lid member can be removed and easily removed and cleaned from the outer tube 14, and the maintainability of the water heat exchanger 10 can be advantageously improved.

  In the above-described embodiment, a simple circular cross-sectional shape heat transfer tube is used as the inner tube through which the heat exchange medium is circulated. However, in the present invention, in addition to such a heat transfer tube, there are various types of heat transfer tubes. Any known heat transfer tube can be used. For example, you may employ | adopt the heat exchanger tube which has a leak detection function which is clarified by Unexamined-Japanese-Patent No. 2005-69620. This is because a leakage detection tube having a large number of grooves formed on the inner peripheral surface is extrapolated to the refrigerant tube, the refrigerant tube is expanded or the leakage detection tube is contracted, and the outer peripheral surface of the refrigerant tube and the leakage detection tube are A large number of leak detection grooves are formed between the leak detection pipe and the refrigerant pipe in close contact with the peripheral surface, and leak detection sensors provided outside are connected to the leak detection grooves. The heat transfer medium or water leaked from the pipe or the outer pipe leaks to the outside through the leak detection groove and is detected by the leak detection sensor. By using a heat transfer tube having such a leakage detection function, it is possible to effectively avoid adverse effects on the human body when the heat transfer medium leaks into water that is subjected to heat exchange. .

  Further, as shown in FIG. 3 of Japanese Patent Application Laid-Open No. 2005-90811, a number of grooves are formed on the inner peripheral surface of the inner tube, and fins are formed between the grooves. As shown in FIG. 5 of Japanese Patent Laid-Open No. 11-23180, the heat transfer promotion was promoted by inserting a spirally twisted strip-shaped tape inside the heat transfer tube. Of course, it is also possible to use a heat transfer tube. By adopting such a heat transfer tube, it is possible to further improve the heat exchange efficiency.

  In addition, although not enumerated one by one, the present invention is carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the present invention.

It is explanatory drawing which notches and shows a part about an example of the water heat exchanger according to this invention. It is explanatory drawing which shows the cross section of the water heat exchanger shown by FIG. 1, Comprising: (a) is AA sectional drawing in FIG. 1, (b) is BB sectional drawing in FIG. Each is shown. It is explanatory drawing which shows an example of the assembly process of the water heat exchanger shown by FIG. 1 in steps, Comprising: (a)-(d) has each schematically shown the one process. It shows about another example of the water heat exchanger according to this invention, Comprising: (a) is partial explanatory drawing shown in a longitudinal cross section, (b) is a cross section which shows CC cross section in (a). It is explanatory drawing, (c) is sectional explanatory drawing which shows the DD cross section in (a). It is explanatory drawing which shows the cross section at the time of combining five inner pipes as another example of the water heat exchanger according to this invention, Comprising: (a) is a hairpin of an inner pipe group from the sealing side of an outer cylinder. It is cross-sectional explanatory drawing which looked at the shape part (bending part), (b) is cross-sectional explanatory drawing which shows the cross section cut | disconnected in the approximate center site | part of the length direction of the water heat exchanger. It is explanatory drawing which shows the cross section at the time of combining six inner pipes as another example of the water heat exchanger according to this invention, (a) is a bending part of an inner pipe group from the sealing side of an outer cylinder. It is a cross-sectional explanatory drawing which looked at (b), and (b) is a cross-sectional explanatory drawing which shows the cross section cut | disconnected in the approximate center part of the length direction of the water heat exchanger. As another example of the water heat exchanger according to the present invention, FIG. 6 shows a modified example of the combination of the inner pipes of the water heat exchanger, and FIG. 6 (a) corresponds to FIG. 6 (a). FIG. 6B is a cross-sectional explanatory diagram at a position corresponding to FIG. 6B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Water heat exchanger 11 Cylindrical inner pipe group 12a, 12b, 12c, 12d Inner pipe 13 Cylindrical part 14 Outer pipe 16 Sealed end part 18 Lid member 20 Crevice 22a Inlet 22b Inlet 24a Inlet 24b Inlet 26 Channel 28 Channel 30a, 30b, 30c, 30d Straight part 32a, 32b, 32c, 32d Hairpin shape part

Claims (5)

One end is closed and a large-diameter outer tube through which water to be heat-exchanged is circulated, and an intermediate portion is formed into a hairpin shape, and the heat exchange medium introduced from one end side has a flow direction of 180. ° It is configured by combining a plurality of small inner pipes that are converted and guided to the other end side, and the hairpin-shaped part of each inner pipe is positioned on the closed end side of the outer pipe in the outer pipe A cylindrical inner tube group, and the cylindrical inner tube group has a cylindrical portion formed by closely arranging the straight portions of the inner tubes on the same circumference, At the tip of the cylindrical inner tube group, a gap is formed between the hairpin-shaped portions of each inner tube, and the inside and outside of the cylindrical inner tube group communicate with each other. Circulates from one of the outside and inside of the cylindrical inner tube group to the other in the outer tube. Water heat exchanger, characterized in that is adapted to be fit.   The water heat exchanger according to claim 1, wherein the gap is formed by shifting a hairpin-shaped portion of each inner tube constituting the cylindrical inner tube group in an axial direction of the cylindrical portion.   The straight portions of the inner tubes constituting the cylindrical portion of the cylindrical inner tube group are arranged so that the straight portion on the inlet side and the straight portion on the outlet side of the heat exchange medium are alternately positioned in the circumferential direction. The water heat exchanger according to claim 1 or 2.   The water according to any one of claims 1 to 3, wherein the water to be heat-exchanged is configured to circulate from the outside to the inside of the cylindrical inner tube group in the outer tube. Heat exchanger. The water heat exchanger according to any one of claims 1 to 4, wherein the heat exchange medium is a refrigerant mainly composed of carbon dioxide gas.

Images