JP2007032943A - Composite heat exchanger tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite heat exchanger tube capable of reducing a volume occupied by the composite heat exchanger tube while maintaining or improving heat transfer performance. <P>SOLUTION: The composite heat exchanger tube 1 comprises a large diameter tube 2, and a small diameter tube 3 having an outside diameter smaller than an inside diameter of the large diameter tube 2, and provided along a tube axis direction inside the large diameter tube, and an outer passage 7 formed between the large diameter tube 2 and the small diameter tube 3 is a passage of a first heating medium W, and an inside of the small diameter tube 3 is a passage of a second heating medium X. At least a part of a total length of the large diameter tube 2 includes a spiral shaped winding part 9. An even number of stages of the winding parts 9 are superimposed, and are wound so that the large diameter tube 2 on an outermost circumference 9d of the winding part 9 abuts on the large diameter tube 2 on an adjacent circumference 9c adjacent to the outermost circumference 9d. Furthermore, both tube end parts 2a, 2b of the large diameter tube 2 are formed on an innermost circumference 9a of the winding part 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat transfer tube used for a heat exchanger such as a refrigerator, a freezer, a water heater, and floor heating, and more specifically, a heat medium flowing between a large-diameter tube and a small-diameter tube through a tube wall. The present invention relates to a composite heat transfer tube that performs heat exchange.

  In general, as a structure of a composite heat transfer tube for a heat exchanger, a structure having a large-diameter tube and a small-diameter tube inside the large-diameter tube is known. In the combined heat transfer tubes of the refrigerator and freezer heat exchanger, refrigerants such as chlorofluorocarbons and alternative chlorofluorocarbon as a heat medium are caused to flow inside the large-diameter tube and the small-diameter tube, and the refrigerant flows through the large-diameter tube and the small-diameter tube. Heat exchange takes place between them. Further, in the composite heat transfer tube of the heat pump unit for hot water heater, water is flown inside the large-diameter tube, and carbon dioxide or alternative chlorofluorocarbon refrigerant is flowed inside the small-diameter tube. Further, in the composite heat transfer tube of the heat exchanger for floor heating, water such as chlorofluorocarbon or alternative chlorofluorocarbon is caused to flow inside the large-diameter tube and to the inside of the small-diameter tube.

Further, as shown in FIG. 10, in order to improve the heat transfer performance, the large-diameter tube 42 is formed with a spiral winding portion 43 at least part of its entire length, and the winding portion 43 is formed in a plurality of stages. A composite heat transfer tube 41 with an increased heat transfer area has been proposed (see, for example, Patent Document 1).
On the other hand, the volume of the composite heat transfer tube 41 occupying the heat pump unit (heat exchanger) while maintaining or improving the heat transfer performance also in the composite heat transfer tube 41 used for the downsizing of the heat pump unit for the water heater, etc. There is a demand to reduce the size.

In the composite heat transfer tube 41, in order to reduce the volume occupied by the composite heat transfer tube 41, it is necessary to reduce the number of stages of the winding portion 43. However, the reduction in the number of stages of the winding portion 43 shortens the overall length of the large-diameter tube 42 and leads to a decrease in the heat transfer performance of the composite heat transfer tube 41. Therefore, the volume occupied by the composite heat transfer tube 41 can be reduced. could not. Therefore, as shown in FIGS. 11A, 11 </ b> B, and 11 </ b> C, the large-diameter pipe 52 has at least a part of its entire length formed in a spiral winding portion 53. A composite heat transfer tube 51 in which the volume occupied by the composite heat transfer tube 51 is reduced without reducing the overall length of the large diameter tube 52 by overlapping a plurality of stages via the transition portion 56 has been studied.
JP 2001-201275 A (FIGS. 2 and 3)

  However, when the composite heat transfer tube 51 is used in a heat pump unit (heat exchanger) or the like, the composite heat transfer tube 51 is housed in the heat insulating case 15 and used. In the composite heat transfer tube 51 of FIG. 11A, since both tube end portions 52a and 52b of the large-diameter tube 52 are formed on the outermost periphery of the winding portion 53, a large-diameter tube 52 and a small-diameter tube (not shown). The space connecting the pipes (not shown) for supplying the first and second heat medium into the pipe ends 52a and 52b becomes the dead space DS as shown by the dotted line in the heat insulating case 15, The heat insulating case 15 is larger by the space, and the volume of the composite heat transfer tube 51 is also increased. Accordingly, there is a problem that the volume of the composite heat transfer tube 51 occupying the heat pump unit (heat exchanger) cannot be sufficiently reduced while maintaining the heat transfer performance.

  Therefore, the present invention was devised to solve such problems, and its purpose is a composite heat transfer tube capable of reducing the volume occupied by the composite heat transfer tube while maintaining or improving the heat transfer performance. Is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 has a large-diameter tube and an outer diameter smaller than the inner diameter of the large-diameter tube, and is provided along the tube axis direction inside the large-diameter tube. A composite heat transfer tube comprising a small-diameter pipe, wherein an outer flow path between the large-diameter pipe and the small-diameter pipe is a first heat medium flow path, and an inside of the small-diameter pipe is a second heat medium flow path. The large-diameter pipe has at least a part of its entire length formed in a spiral winding portion, the winding portions are stacked in an even number of stages, and the large-diameter tube on the outermost periphery of the winding portion. Is wound so as to be in contact with the large-diameter tube adjacent to the outermost periphery, and both end portions of the large-diameter tube are formed on the innermost periphery of the wound portion. It is constituted as follows.

  According to the above-described configuration, the spirally wound portions are stacked in even stages, and the outermost large-diameter tube of the wound portion is formed so as to abut on the adjacent peripheral large-diameter tube adjacent to the outermost periphery. This increases the length of the composite heat transfer tube that can be stored in the same volume, increases the heat transfer area of the composite heat transfer tube, and stores the composite heat transfer tube in the heat exchanger by storing it in a heat insulating case. In doing so, the volume of the heat insulating case can be reduced. In addition, since both pipe end portions of the large diameter pipe are formed on the innermost circumference of the winding portion, the connection process with the piping for supplying the heat medium is performed inside the winding portion, and the heat insulating case When the composite heat transfer tube is housed in the heat insulating case, a dead space required for connection processing is not formed in the heat insulating case.

Further, in the invention according to claim 2, the winding portion has the large-diameter pipe at each stage abutting against the large-diameter pipe at the adjacent stage, and the large-diameter pipe at each circumference of the winding part. It is configured as a composite heat transfer tube formed so as to be in contact with the adjacent large-diameter tube.
According to the said structure, when accommodating a composite heat exchanger tube in a heat insulation case, a space part is not formed between large diameter pipes, but a dead space is not formed in a heat insulation case by the space part.

Moreover, the invention which concerns on Claim 3 WHEREIN: As for the said winding part, in the plane which the winding shape orthogonally crosses with respect to a winding axis | shaft, it is a composite heat exchanger tube which is an oval shape which has a straight path and a curved path alternately. It is composed.
According to the above configuration, when the winding shape is an oval shape, when the composite heat transfer tube is housed in the heat insulating case and installed in the heat exchanger, the volume of the heat insulating case can be reduced, It is difficult for the heat insulation case to be displaced in the heat exchanger. Moreover, when forming a winding part using a commercially available bending machine, a bending process becomes easy.

According to a fourth aspect of the present invention, both the tube end portions are configured as a composite heat transfer tube formed in the same direction.
According to the said structure, the connection process of both pipe | tube edge part and piping etc. which supply a heat carrier becomes easy.

  In the invention according to claim 5, the small-diameter pipe includes an outer pipe and an inner pipe that is coaxially provided inside the outer pipe and has an outer diameter smaller than the inner diameter of the outer pipe. This is configured as a composite heat transfer tube which is a double tube in which a space is formed between the tube and the inner tube.

  According to the above configuration, even if the inner pipe is damaged due to corrosion or the like, the inner pipe is formed by the double pipe in which the space portion is formed between the outer pipe and the inner pipe. And the outer flow path (flow path of the first heat medium) are not in communication with each other, and there is no possibility that foreign matter (oil or the like) of the second heat medium is mixed into the first heat medium. Furthermore, with this double pipe structure, even if the second heat medium leaks due to the damage of the inner pipe, the outer pipe can minimize the sudden damage of the inner pipe, which occurs at this time. By detecting leakage from the space formed between the outer tube and the inner tube at two locations on both ends of the heat transfer tube, the damage state can be examined. Similarly, even when the outer tube surface on the first heat medium side corrodes for some reason and a corrosion hole is formed in the outer tube, leakage from the space formed between the outer tube and the inner tube, The damage status can be examined by detecting at the two ends of the heat transfer tube.

The invention according to claim 6 is configured as a composite heat transfer tube in which the direction in which the first heat medium flows and the direction in which the second heat medium flows are opposed to each other.
According to the above configuration, the heat transfer efficiency between the first heat medium and the second heat medium is improved, and the amount of heat transfer is increased.

The invention according to claim 7 is configured as a composite heat transfer tube in which the first heat medium is water and the second heat medium is a refrigerant.
According to the above configuration, the heat transfer efficiency between the first heat medium and the second heat medium is improved, and the amount of heat transfer is increased.

According to an eighth aspect of the present invention, at least one of the large diameter tube and the small diameter tube is configured as a composite heat transfer tube made of copper or a copper alloy.
According to the above configuration, the heat transfer efficiency between the first heat medium and the second heat medium is improved, and the amount of heat transfer is increased.

  According to the present invention, the winding portions formed in the large-diameter pipe are stacked in an even number of stages so that the outermost large-diameter tube of the winding portion comes into contact with the adjacent large-diameter pipe adjacent to the outermost periphery. In addition, both ends of the large-diameter pipe are formed on the innermost circumference of the winding part, thereby reducing the volume occupied by the composite heat transfer pipe while maintaining or improving the heat transfer performance. Can do. In addition, that the volume of the composite heat transfer tube can be reduced, in other words, the volume of the heat insulating case that houses the composite heat transfer tube can also be reduced, and the heat insulation efficiency can be improved. And the full length of the composite heat exchanger tube accommodated in the heat insulation case of the same volume will become long, and heat transfer performance will improve. Moreover, the volume of the composite heat transfer tube can be further reduced by forming the winding portions so that the large-diameter tubes at the respective stages and the circumferences come into contact with each other.

  In addition, since the winding shape of the winding portion is an oval shape, the volume occupied by the composite heat transfer tube is further reduced in the heat insulation case of a rectangular parallelepiped shape, and the heat insulation case (composite heat transfer tube) in the heat exchanger This improves the installation stability and improves the productivity of composite heat transfer tubes. Furthermore, both pipe end parts of the large diameter pipe are formed in the same direction with respect to the winding axis, thereby further improving the productivity of the composite heat transfer pipe.

  In addition, by configuring the small-diameter tube with a double tube in which a space portion is formed, the leakage of the second heat medium to the first heat medium can be prevented, and the leakage can be detected, so that the safety of the composite heat transfer tube can be improved. Improves.

  In addition, the flow direction of the first heat medium and the second heat medium is opposed to each other, at least one of the large diameter pipe and the small diameter pipe is made of copper or a copper alloy using water as the first heat medium and refrigerant as the second heat medium. By comprising, the heat-transfer performance of a composite heat exchanger tube can be improved further.

  Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a plan view showing the structure of a composite heat transfer tube, FIG. 2 (a) is a cross-sectional view taken along line AA in FIG. 1, (b) is a cross-sectional view taken along line BB in FIG. c) is an enlarged cross-sectional view of the large-diameter pipe, FIG. 3 (a) is a plan view showing another form of the winding portion, and (b) is a cross-sectional view taken along the line CC of FIG. 4 (a) is a plan view showing another form of the winding part, (b) is a schematic view showing a state in which the units are stacked in parallel, and (c) and (d) are in a state where they are stacked in series. FIG. 5A is a cross-sectional view orthogonal to the tube axis of a large-diameter tube of another embodiment of the composite heat transfer tube, FIG. 5B is an enlarged cross-sectional view of the small-diameter tube of FIG. FIG. 7 is a partially broken perspective view showing the configuration of the composite heat transfer tube in which the bundling member and the inner material are arranged, and FIG. Combined heat transfer tubes Indicates, (a) represents a partially broken side view, (b) is an explanatory view schematically showing D-D line cross-sectional view, FIG. 9 is a configuration of a water heater using the composite heat exchanger tube of (a).

  A first embodiment of the composite heat transfer tube of the present invention is shown in FIGS. 1, 2 (a), 2 (b), and (c). As shown in FIG. 1, FIG. 2 (a), (b), (c), the composite heat transfer tube 1 of the present invention has a large diameter tube 2 and an outer diameter smaller than the inner diameter of the large diameter tube 2, A small-diameter pipe 3 provided inside the large-diameter pipe 2, the outer flow path 7 between the large-diameter pipe 2 and the small-diameter pipe 3 is used as a flow path for the first heat medium W, and the inside of the small-diameter pipe 3 is As a flow path for the second heat medium X, at least a part of the entire length of the large-diameter pipe 2 is formed in a spiral winding portion 9, and the winding portion 9 is stacked in an even number of stages, Both tube end portions 2 a and 2 b of the tube 2 are formed on the innermost periphery 9 a of the winding portion 9. Each configuration will be described below.

(Large diameter pipe)
As shown in FIG. 2C, the large diameter pipe 2 is formed by forming an outer flow path 7 between the large diameter pipe 3 and a small diameter pipe 3 to be described later, and the outer flow path 7 is used as a flow path of the first heat medium W. is there. Further, the inner diameter of the large-diameter pipe 2 is larger than the outer diameter of the small-diameter pipe 3 to be described later, and the inner diameter and the pressure resistance sufficient to allow the first heat medium W to flow through the outer flow path 7 are only an example. The outer diameter is preferably 4 to 30 mm, the wall thickness is 0.2 to 2.5 mm, and the length is preferably 100 mm or more. The dimensions of the large diameter pipe 2 are related to the dimensions of the small diameter pipe 3 described later, the dimensions of the heat exchanger 30 (see FIG. 9, hot water heater in the figure) in which the composite heat transfer pipe 1 of the present invention is incorporated, From the viewpoint of heat transfer performance and pressure loss of the composite heat transfer tube 1, the cross-sectional area of the single small diameter tube 3 in the cross section orthogonal to the tube axis, the large diameter tube 2, and the small diameter tube 3 are determined. It is more preferable that the ratio (outer channel cross-sectional area / small-diameter pipe channel cross-sectional area) with the cross-sectional area of the outer channel 7 between the two is set to satisfy the range of 10-50.

  The material of the large-diameter tube 2 is (1) excellent in thermal conductivity, and can efficiently exchange heat between the large-diameter tube 2 and a heat medium flowing inside the small-diameter tube 3 described later. (2) The composite heat transfer tube 1 is Excellent corrosion resistance in various atmospheres used. (3) Formation of spiral winding portion 9 described later, formation of uneven portion 19 (see FIG. 8), and incorporation into heat exchanger (hot water heater) 30 Excellent plastic workability such as bending (having mechanical properties that do not cause cracking or the like by processing), (4) brazing with a pipe for supplying the first heat medium W to the outer flow path 7, soldering It is preferable to satisfy the characteristics such as excellent properties or adhesiveness by an adhesive, and (5) excellent pressure resistance at the pressure at which the composite heat transfer tube 1 is used.

  As a material satisfying these characteristics (1) to (5), copper or a copper alloy widely used as a heat exchanger tube for a heat exchanger such as an air conditioner or a large air conditioner is preferable. Alloy number C1101 defined in JISH3300 More preferred are oxygen-free copper, and phosphorus-deoxidized copper having alloy numbers C1201 and C1220.

  Moreover, it is not necessary to limit only to the said material, When especially heat conductivity and a pressure | voltage resistant strength are required, the copper or copper alloy prescribed | regulated to JISH3300, for example, Fe, P, Ni, Co, Mn, Sn, It is also possible to use a copper alloy not specified in JISH3300 in which one or two or more elements selected from elements such as Si, Mg, Ag, and Al are contained in Cu in a total of several percent or less.

  Further, when particularly corrosion resistance and pressure strength are required, Cu—Ni alloys such as alloy numbers C7060, C7100, and C7150 defined in JISH3300, Ti or Ti alloys, stainless steel, and the like can be used. When weight reduction is required, it is possible to select one having predetermined characteristics from aluminum and aluminum alloys in consideration of characteristics such as corrosion resistance, strength, and workability.

  The pipe constituting the large-diameter pipe 2 may be a seamless pipe produced by rolling and drawing an extruded element pipe, or a welded pipe produced by welding end faces in the width direction of a predetermined width of a strip. Good.

  In general, a smooth tube having a smooth tube inner surface is often used as the large-diameter tube 2. However, when the first heat medium W in the outer flow path 7 is desired to be stirred, a swirl flow is desired, or When it is desired to increase the heat transfer area, an internally grooved tube in which a groove parallel to the tube axis direction or a spiral groove (not shown) is formed on at least a part of the tube inner surface may be used. . For grooving in the large-diameter pipe 2, a rolling method, a rolling method (a rolling roll is used instead of a rolling ball), and a strip (a narrow plate shape) are grooved with a rolling roll. A method such as rounding and welding the ends may be used.

(Small diameter pipe)
As shown in FIG. 2 (c), the small diameter tube 3 has an outer diameter smaller than the inner diameter of the large diameter tube 2, and is provided along the tube axis direction inside the large diameter tube 2. The inside of the small diameter tube 3 is used as a flow path for the second heat medium X. The small-diameter pipes 3 are preferably provided in the range of three to six. Further, as the arrangement of the small-diameter pipes 3 in the large-diameter pipe 2, an arrangement in which the outer flow path 7 is equally divided is preferable. . By arranging the small-diameter pipe 3 in this way, heat transfer from the small-diameter pipe 3 to the outer flow path 7 (large-diameter pipe 2) is improved, and the pressure loss of the first heat medium W is also reduced. However, if heat transfer is improved and the pressure loss is low, the arrangement other than that shown in FIG. The reason why the small diameter pipe 3 is provided in the range of 3 to 6 is that the heat transfer area is not sufficient when the number is 2 or less, and the pressure of the first heat medium W by the small diameter pipe 3 is 7 or more. This is because loss increases.

  The small diameter pipe 3 is provided along the tube axis direction of the large diameter pipe 2 so as to form the outer flow path 7 inside the large diameter pipe 2, and the first heat medium W is required in the outer flow path 7. It is formed in a dimension that allows mass distribution. As an example, the outer diameter is preferably 1 to 8 mm, the wall thickness is 0.2 to 5 mm, and the length is preferably 100 mm or more. Further, as described above, the dimension of the small diameter tube 3 is one small diameter in the cross section perpendicular to the tube axis from the viewpoint of the heat transfer performance of the composite heat transfer tube 1 and the pressure loss of the first heat medium W and the second heat medium X. The ratio of the cross-sectional area of the tube 3 to the cross-sectional area of the outer channel 7 between the large-diameter tube 2 and the small-diameter tube 3 (outer channel cross-sectional area / small-diameter tube channel cross-sectional area) is 10 to 50 It is more preferable to set so as to satisfy the range.

  The material of the small diameter pipe 3 is the same as that selected for the large diameter pipe 2, and the same or different material as the large diameter pipe 2 is appropriately selected.

  Since the pipes constituting the small-diameter pipe 3 are often operated by increasing the internal pressure of the second heat medium X supplied to the inside thereof, the wall thickness with respect to the outer diameter of the pipe is often increased. In many cases, a seamless tube produced by rolling and drawing an extruded element tube is used. The wall thickness of the tube may be determined from the pressure strength calculated based on the operating pressure of the heat exchanger. A welded pipe may be used as long as the pressure resistance satisfies the required value. Further, when it is desired to stir the second heat medium X, to provide a swirling flow, or to increase the heat transfer area in the pipe, an inner grooved pipe may be used in the same manner as the large diameter pipe 2. Good.

(Heat medium)
As the heat medium, water or a refrigerant is used, and it is preferable that the first heat medium W is water and the second heat medium X is a refrigerant because heat transfer efficiency between the heat mediums is good. As the refrigerant, a high-pressure refrigerant is more preferable, and examples thereof include carbon dioxide, hydrofluorocarbon (HFC) refrigerant, and the like, which are appropriately selected in consideration of the use of the heat exchanger in which the composite heat transfer tube 1 is incorporated. In particular, the second heat medium X is preferably carbon dioxide from the viewpoint of the environment, and more preferably, carbon dioxide is used in a supercritical state in terms of excellent thermal efficiency.

  In consideration of performance efficiency (COP) such as a heat pump, the second heat medium X is preferably a hydrofluorocarbon (HFC) refrigerant. The hydrofluorocarbon (HFC) refrigerant is a refrigerant that does not destroy ozone by substituting all the chlorine in the conventionally used chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerant with hydrogen. A typical HFC refrigerant is R410A which is a non-azeotropic refrigerant mixture in which R32 and R125 are mixed. Furthermore, it is more preferable to use the HFC refrigerant in an almost critical state.

  Furthermore, it is preferable that the direction in which the first heat medium W flows and the direction in which the second heat medium X flows are opposed to each other. Thereby, heat transfer from the second heat medium X to the first heat medium W is efficiently performed. However, the flow direction of the second heat medium X and the first heat medium W may be the same direction as long as a sufficient amount of heat transfer is obtained.

(Winding part)
As shown in FIG. 1, the large-diameter tube 2 has at least one part of its entire length formed in a spiral winding part 9. The maximum outer diameter OD and minimum inner diameter ID of the winding of the winding portion 9 are the outer diameter, thickness, crystal grain size, mechanical properties (tensile strength, proof stress, large diameter pipe 2 and small diameter pipe (not shown)). For example, when the outer diameter of the large diameter pipe 2 is a constant “n”, the maximum outer diameter OD of the winding portion 9 is large up to about 40 times “n”. Further, the minimum inner diameter ID can be reduced to about 6 times “n”. In addition, the winding direction of the winding part 9 may be either right-handed or left-handed with respect to the winding shaft.

  As shown in FIGS. 1, 2 (a) and 2 (b), the winding portions 9 are stacked in an even number of stages, and both pipe end portions 2 a of the large-diameter pipe 2 that are the start and end of winding of the winding portion 9. 2b is formed in the innermost periphery 9a of the winding part 9. That is, in the first-stage winding portion 9A, the large-diameter pipe 2 is wound from the innermost periphery 9a toward the outermost periphery 9d, and through the transition portion 12, the second-stage winding portion 9B is large. The diameter pipe 2 is wound from the outermost periphery 9d toward the innermost periphery 9a. As described above, the pipe ends 2a and 2b are formed on the innermost circumference 9a, so that the connection of the pipes and the like (not shown) for supplying the heat medium and the pipe ends 2a and 2b is performed on the winding portion 9. Thus, when the composite heat transfer tube 1 is housed in the heat insulation case 15, the dead space DS (see FIG. 11A) required for the connection process is not formed in the heat insulation case 15. Thereby, the volume of the heat insulation case 15 can be reduced. Moreover, it is preferable that both pipe end parts 2a and 2b are formed toward the same direction. By being in the same direction, the connection processing between the pipe end portions 2a, 2b and the piping is facilitated, and the productivity of the composite heat transfer tube is further improved.

  When the number of stages of the winding part 9 is more than two, such as four stages, eight stages, etc., the two-stage winding parts 9A and 9B are regarded as one unit 14 as shown in FIG. Or in series as shown in FIGS. 4 (c) and 4 (d). When stacked in parallel, the pressure loss of the composite heat transfer tube 1 can be suppressed, and when stacked in series, the heat transfer area of the composite heat transfer tube 1 can be increased. . At this time, the connections between the units 14 are made by connecting the pipe ends 2a, 2b of each unit 14 and piping (not shown) directly (brassing etc.) or using connecting pipes etc. (not shown). Alternatively, each unit 14 (winding portions 9A and 9B) may be formed continuously in the full length direction of the large-diameter pipe 2.

  The winding portion 9 is formed such that the large diameter tube 2 of the outermost periphery 9d abuts the large diameter tube 2 of the adjacent periphery 9c adjacent to the outermost periphery 9d. If it does in this way, the winding part 9 will be compactized and the volume which the composite heat exchanger tube 1 occupies will become small. As shown in FIGS. 3A and 3B, in the curved path 11 of the winding portion 9, the large-diameter pipe 2 of each circumference (9a, 9b, 9c, 9d) has an outermost circumference 9d and its outermost circumference. If only the adjacent circumference 9c adjacent to the outer periphery 9d is in contact, the large diameter pipe 2 of the other circumference (9a, 9b, 9c) does not contact the adjacent large diameter pipe 2 and the gap portion 13 may be formed. By forming the gap 13, when the large-diameter pipe 2 is bent to form the wound portion 9, the radius of the curved path 11 becomes the same, and the workability of bending is improved.

  Moreover, it is preferable that the large diameter pipe 2 of each circumference | surroundings (9a, 9b, 9c, 9d) and each step (9A, 9B) of the winding part 9 contact | abuts the adjacent large diameter pipe 2. FIG. Further, it is more preferable that the outer shape of the large-diameter pipe 2 in the cross section perpendicular to the axis of the pipe is an ellipse or a flat circle (not shown). 9 can be reduced. If (vertical diameter <right and left diameter), the height H of the winding portion 9 can be reduced.

  The winding portion 9 preferably has an oval shape having alternately a straight path 10 having a predetermined length and a curved path 11 having a predetermined radius on a plane in which the winding shape is orthogonal to the winding axis. Such an oval winding shape enables the volume of the heat insulating case 15 to be reduced when the composite heat transfer tube 1 is housed in the heat insulating case 15 and installed in the heat exchanger. The positional deviation of the heat insulation case 15 is less likely to occur, and the installation stability is improved. Moreover, when forming the winding part 9 using a commercially available bending machine, a bending process becomes easy and productivity improves.

  The winding shape of the winding portion 9 is not limited to the oval shape in which the curved path 11 in FIG. 1A is formed by a quarter circle, but is an oval shape in which the curved path 11 is formed by a half circle. There may be. Moreover, as shown to Fig.4 (a), the winding shape of the winding part 9 may be circular. And the circular winding part 9 is the minimum inner diameter ID, the maximum outer diameter OD, the number of steps, the transition part 12 of the winding part 9, the contact state between the large diameter pipes 2, and the outer shape of the large diameter pipe 2. The same as the oval winding part 9.

  Next, 2nd Embodiment of the composite heat exchanger tube of this invention is shown to Fig.5 (a). As shown in FIG. 5 (a), the composite heat transfer tube 1a includes a small diameter tube 3 of the composite heat transfer tube 1 of the first embodiment, which is composed of an outer tube 4 and an inner tube 5. And the inside of the inner pipe 5 is used as a flow path for the second heat medium X. Here, the same code | symbol is attached | subjected to the structure same as the composite heat exchanger tube 1 of 1st Embodiment, and description is abbreviate | omitted. Moreover, although not shown in figure, the large diameter pipe 2 is formed in the spiral winding part at least a part of the full length.

(Outer pipe)
The outer tube 4 is provided along the tube axis direction of the large-diameter tube 2 so as to form the outer channel 7 inside the large-diameter tube 2, and the first heat medium W is required for the outer channel 7. It is formed in a dimension that allows mass distribution. As an example, the outer diameter is preferably 1 to 8 mm, the wall thickness is 0.2 to 5 mm, and the length is preferably 100 mm or more. Further, as described above, the dimension of the outer tube 4 is one small diameter in the cross section orthogonal to the tube axis from the viewpoint of the heat transfer performance of the composite heat transfer tube 1 and the pressure loss of the first heat medium W and the second heat medium X. Ratio of the cross-sectional area of the pipe 3 (inner pipe 5) and the cross-sectional area of the outer flow path 7 between the large-diameter pipe 2 and the small-diameter pipe 3 (outer-channel cross-sectional area / small-diameter pipe (inner pipe 5) More preferably, the flow path cross-sectional area is set to satisfy the range of 10-50.

  The same material as that selected for the large-diameter tube 2 is applied as the material of the outer tube 4, and the same or different material as that for the large-diameter tube 2 is appropriately selected.

  Since the pipe constituting the outer pipe 4 is often operated by increasing the internal pressure of the inner pipe 5 provided therein, the wall thickness is often increased with respect to the outer diameter of the pipe. In many cases, a seamless tube produced by rolling and drawing a tube is used. The wall thickness of the tube may be determined from the pressure strength calculated based on the operating pressure of the heat exchanger. A welded pipe may be used as long as the pressure resistance satisfies the required value.

  The outer tube 4 has a groove or a spiral shape parallel to the tube axis direction on at least a part of the inner surface of the tube described in the large-diameter tube 2 so that a space 6 is formed between the outer tube 4 and the inner tube 5 described later. It is preferable to use an internally grooved tube in which a groove (not shown) is formed. However, when using a tube having a projection on the outer surface of the tube as the inner tube 5, a smooth tube having a smooth tube inner surface may be used as the outer tube 4.

(Inner pipe)
The inner tube 5 is coaxially provided inside the outer tube 4, has an outer diameter smaller than the inner diameter of the outer tube 4, forms a space 6 between the inner tube 5, and a second inside thereof. The heat medium X is formed in a size that allows a necessary amount to flow. As an example, the outer diameter is preferably 1 to 8 mm, the wall thickness is 0.2 to 5 mm, and the length is preferably 100 mm or more. The flow path cross-sectional area of one small diameter tube 3 in the tube axis orthogonal section, the large diameter tube 2 and The ratio of the cross-sectional area of the outer flow path 7 to the small-diameter pipe 3 (inner pipe 5) (outer-flow-path cross-sectional area / small-diameter pipe (inner pipe 5) flow-path cross-sectional area) satisfies the range of 10-50. It is more preferable to set so. The material of the inner tube 5 is appropriately selected from the same or different material from that of the outer tube 4.

  The pipes constituting the inner pipe 5 have a small cross-sectional area, but since there are many cases where it is desired to increase the flow rate of the second heat medium X flowing through the inner pipe 5, the pipe is often operated with a high internal pressure. Therefore, the wall thickness is often increased with respect to the outer diameter of the pipe, and in general, a seamless pipe produced by rolling and drawing an extruded element pipe is often used. The wall thickness of the tube may be determined from the pressure strength calculated based on the operating pressure of the heat exchanger. A welded pipe may be used as long as the pressure resistance satisfies the required value. In addition, when the pressure of the refrigerant flowing through the inner pipe is high and the temperature is high, the inner pipe and / or the outer pipe are creep-deformed by long-term use, the contact state between the inner pipe and the outer pipe is deteriorated, and the refrigerant (first Heat transfer from the second heat medium X) to the first heat fluid may be hindered. In that case, it is desirable to use a material such as a copper alloy having excellent creep resistance for the inner tube and / or the outer tube.

  In general, a smooth tube having a smooth inner surface is often used as the inner tube 5. However, when the second heat medium X in the tube is to be stirred, a swirl flow is desired, or the heat transfer area in the tube is increased. For example, an internally grooved tube in which a groove parallel to the tube axis direction or a spiral groove (not shown) is formed on at least a part of the tube inner surface may be used.

  As described above, in order to form the space 6 between the inner tube 5 and the outer tube 4 (smooth tube), a tube provided with a protrusion on the outer surface of the tube may be used.

(Space part)
The space 6 has an effect of preventing foreign matters (oil, etc.) from entering the outer flow path 7 (first heat medium W) when the inner pipe 5 is damaged due to corrosion or the like. Since the second heat medium X flowing through the air flows in, the amount of the second heat medium X that has flowed in, for example, carbon dioxide, is measured from the outside to detect the damage (corrosion, etc.) of the inner pipe 5 from the outside. Have the effect of Therefore, the cross-sectional area of the space portion 6 is 0.5 to 3 mm ² is preferred, the second heat medium X is a second heat medium X hardly reach the external flowing into the space 6 is less than 0.5 mm ² It becomes difficult to detect, and if it exceeds 3 mm ² , the contact area between the inner tube 5 and the outer tube 4 becomes small, and the amount of heat transfer from the second heat medium X tends to decrease.

  For example, the space 6 is formed by inserting the inner tube 5 (inner grooved tube or smooth tube) into the outer tube 4 (inner grooved tube) and emptying the inner tube 5 to the outer tube 4 by caulking. Make it. However, the manufacturing method is not limited to the above-described manufacturing method as long as the space portion 6 having an effect of preventing contamination and detecting the damage (corrosion or the like) of the inner tube 5 can be manufactured.

  Next, 3rd Embodiment of the composite heat exchanger tube of this invention is shown in FIG. 6, FIG. As shown in FIGS. 6 and 7, the composite heat transfer tube 1 b obstructs a part of the flow of the first heat medium W in the configuration of the composite heat transfer tube 1, 1 a of the first or second embodiment. The heat transfer promotion member 8 which becomes becomes further provided. Here, the same code | symbol is attached | subjected to the structure same as the composite heat exchanger tube 1, 1a of 1st or 2nd embodiment, and description is abbreviate | omitted. Moreover, although not shown in figure, you may form the uneven | corrugated | grooved part 19 (refer FIG. 8) mentioned later to the large diameter pipe 2. FIG.

(Heat transfer promotion member)
The heat transfer promoting member 8 is disposed in at least a partial region S of the entire length of the outer flow path 7. As the heat transfer promotion member 8, a baffle material 8a, an inner material 8b, a bundling member 8c, a combination of the bundling member 8c and the baffle material 8a shown below, or a bundling member 8c and an inner material 8b are combined. Those are preferred. By arranging the heat transfer promoting member 8 in this way, the flow path length of the first heat medium W is increased and the temperature of the first heat medium W is made uniform due to the generation of turbulent flow. The amount of heat transfer to the first heat medium W is further increased, and the pressure loss of the first heat medium W is also reduced. Further, the region S (length) in which the heat transfer promoting member 8 is arranged is set to a length that does not increase the pressure loss of the first heat medium W flowing through the outer flow path 7, and the inner pipe in the region S is It is preferable to set in consideration of the temperature of the flowing second heat medium X. However, the heat transfer promotion member 8 hinders a part of the flow of the first heat medium W, generates a turbulent flow in the flow of the first heat medium W, and has a large pressure loss of the first heat medium W. As long as it does not, it is not limited to the baffle material 8a, the inner material 8b, the bundling member 8c, or the like.

(Baffle material)
As shown in FIG. 6, the baffle material 8 a includes a plate-shaped blocking portion 17 smaller than an orthogonal cross section orthogonal to the tube axis direction of the large-diameter tube 2 and a small-diameter tube 3 (2 in FIG. 6) provided on the surface thereof. The small-diameter pipe 3 is inserted through the insertion holes 16 and 16 and is arranged in the outer flow path 7 along the tube axis direction of the large-diameter pipe 2. Further, in order to prevent the baffle material 8a from moving due to the flow of the first heat medium W, at least one part of the blocking portion 17 of the baffle material 8a is bonded to the outer surface of the small diameter tube 3 inserted through the insertion holes 16 and 16. It is joined with an agent, wax or the like (not shown).

  The baffle material 8a is made of ceramic, copper, stainless steel or the like that does not corrode or contaminate the first heat medium W by the first heat medium W (for example, water), and the shape thereof is defective as shown in FIG. It is circular and it is preferable that the area of the plate surface involved in obstruction of the first heat medium W of the obstruction part 17 is 20 to 80% with respect to the cross section of the outer flow path 7 perpendicular to the tube axis. If it is less than 20%, the disturbing property of the first heat medium W becomes too low and the frequency of occurrence of turbulence tends to be low, and if it exceeds 80%, the disturbing property of the first heat medium W becomes too high. 1 The pressure loss of the heat medium W tends to increase. Moreover, although the baffle material 8a has described the example in which the plate | board surface of the obstruction | occlusion part 17 orthogonally crosses with respect to the pipe axis of the small diameter pipe 3 in FIG. It may be tilted forward or backward (not shown). Further, the disturbing portion 17 may be configured to reduce the flow resistance of the first heat medium W by forming one or more through holes (not shown).

  As shown in FIG. 6, the arrangement of a plurality of baffle members 8a, 8a,... Arranged along the tube axis direction of the large-diameter pipe 2 is an outer flow that is disturbed by the respective disturbing portions 17, 17. The path 7 is preferably different between adjacent baffle members 8a. Thereby, the part which accept | permits the flow of the 1st heat medium W will differ for every baffle material 8a, 8a ..., and it is 1st in the area | region S where several baffle material 8a, 8a ... was arrange | positioned. The flow of the heat medium W becomes complicated (spiral shape in FIG. 6), the flow path length is further increased, and turbulent flow is easily generated. If turbulent flow occurs and the pressure loss of the first heat medium W does not increase, a baffle material other than that shown in FIG. 6 may be used.

  In addition, when the second heat medium X is carbon dioxide, the plurality of baffle materials 8a, 8a,... Satisfy a permissible range of 20 to 80 ° C. in which the local heat transfer coefficient of carbon dioxide is maximized. It is preferable to arrange in the outer flow path 7 corresponding to S. And the setting of such area | region S is performed using the temperature of the carbon dioxide measured beforehand over the full length of the inner tube | pipe. And the pressure of a carbon dioxide is normally utilized in the range of 8-11 Mpa, However, It changes with systems of the heat exchanger in which the composite heat exchanger tube 1a is integrated. By setting the region S in this way, the baffle materials 8a, 8a,... Are arranged in a region where the heat transfer coefficient of the second heat medium X (carbon dioxide) is large, and the second heat medium X (dioxide dioxide). Heat transfer from carbon) to the first heat medium W (water) is efficiently performed, and the amount of heat transfer from the second heat medium X (carbon dioxide) to the first heat medium W (water) is further increased.

(Inner material)
As shown in FIGS. 7A, 7B, and 7C, the inner member 8b includes a main body portion 18 that extends along the tube axis direction of the large-diameter tube 2, and is interposed between the plurality of small-diameter tubes 3. It is interposed and is arranged coaxially with the large diameter pipe 2. In addition, at least a part of the inner material 8b is joined to the outer surface of the small diameter tube 3 with an adhesive, brazing, or the like so that the inner material 8b does not move due to the flow of the first heat medium W (not shown). ).

  The inner material 8b is made of ceramic, copper, stainless steel or the like which does not corrode or contaminate the first heat medium W by the first heat medium W (for example, water), and the shape thereof is shown in FIGS. 7B and 7C. As shown, a rod-like body or a tubular body is preferable, and a tubular body is more preferable in consideration of a decrease in pressure loss. Moreover, although not shown in figure, a spherical body (a spherical shape includes an elliptical sphere) may be sufficient. And it is preferable that the cross-sectional area in the pipe axis orthogonal cross section of the inner material 8b is designed to be 20 to 80% with respect to the cross-sectional area of the outer flow path 7. If it is less than 20%, the disturbing property of the first heat medium W becomes too low and the frequency of occurrence of turbulence tends to be low, and if it exceeds 80%, the disturbing property of the first heat medium W becomes too high. 1 The pressure loss of the heat medium W tends to increase.

  Similar to the baffle material 8a, the inner material 8b is an outer side corresponding to a region S that satisfies an allowable range of a temperature range of 20 to 80 ° C. in which the local heat transfer coefficient of the second heat medium X is maximized in actual operation. It is preferable to arrange in the flow path 7. In addition, the inner material 8b may have a length in the tube axis direction of the main body 18 that is not limited to the entire length of the region S but may be shorter than the entire length of the region S. In the case of the inner member 8b having a short length of the main body portion 18, a plurality of regions are arranged over the region S at a predetermined interval.

(Bundled member)
As shown in FIG. 7 (a), the bundling member 8c is inscribed in the plurality of small diameter pipes 3 and bundles the plurality of small diameter pipes 3, and has a predetermined distance S3 in the tube axis direction of the large diameter pipe 2. It is arranged in plural. The bundling member 8c is made of ceramic, copper, stainless steel or the like that does not corrode or contaminate the first heat medium W by the first heat medium W (for example, water), and the form is preferably a ring shown in FIG. . However, although not shown, as long as it has a function of bundling the small-diameter pipes 3, a C-ring having a deficient portion in a part of the ring, or a form in which a wire is wound in a ring shape may be used. Further, the bundled state of the small diameter tubes 3 shows a strong bundled state in which the small diameter tubes 3 are in contact with each other in FIG. 7A, but if the bundle member 8 c is inscribed in the small diameter tube 3, It may be in a weakly bundled state in which a space is formed between them. Furthermore, the distance S3 of the bundling member 8c is preferably 60 to 600 mm. If the distance is less than 60 mm, it is difficult to manufacture the composite heat transfer tube 1b, and if it exceeds 600 mm, turbulent flow is unlikely to occur in the first heat medium W.

  Like the baffle material 8a or the inner material 8b, the bundling member 8c is a region S that satisfies an allowable range of 20 to 80 ° C. in which the local heat transfer coefficient of the second heat medium X is maximized in actual operation. It is preferable to arrange in the outer flow path 7 corresponding to.

(Combination of bundling member and baffle material or inner material)
The heat transfer promoting member 8 is configured by the plurality of bundling members 8c and the baffle material 8a (see FIG. 6) provided between the bundling members 8c, or provided between the plurality of bundling members 8c and the bundling members 8c. And an inner member 8b interposed between the plurality of small-diameter pipes 3.

  As shown in FIG. 7A, when the heat transfer promoting member 8 is composed of a bundling member 8c and an inner material 8b, the distance S3 between the bundling member 8c and the bundling member 8c is 60 to 600 mm, and the inner material The distance S4 between 8b and the inner material 8b is preferably 60 to 600 mm, and the distance S5 between the bundling member 8c and the inner material 8b is preferably 30 to 300 mm. When the distance (S3, S4, S5) is less than the range, it is difficult to manufacture the composite heat transfer tube 1b. When the distance (S3, S4, S5) is more than the range, turbulence is hardly generated in the first heat medium W. Further, the outer diameter of the inner material 8b is preferably equal to or smaller than the outer diameter of the small diameter tube 3. When the outer diameter of the inner material 8b is larger than the outer diameter of the small diameter tube 3, the pressure loss increases and it becomes difficult to dispose the inner material 8b between the plurality of small diameter tubes 3. Furthermore, as shown in FIGS. 7B and 7C, the length S2 of the inner member 8b is preferably 1 to 50 mm. If the length S2 is less than 1 mm, the strength of the inner material 8b is insufficient, making it difficult to manufacture the composite heat transfer tube 1b, and if it exceeds 50 mm, turbulence is unlikely to occur in the first heat medium W.

  As described above, when the inner member 8b is disposed between the bundling members 8c, the plurality of small-diameter tubes 3 are sunk by the bundling of the small-diameter tubes 3 by the bundling members 8c, and the inner member 8b is interposed between the small-diameter tubes 3. Fixed. Further, by inserting the inner material 8 b between the small diameter tubes 3, the plurality of small diameter tubes 3 inscribed in the bundle member 8 c are expanded, and the bundle members 8 c are fixed to the small diameter tube 3. And in order to strengthen fixation to the small diameter pipe | tube 3 of the bundle member 8c and the inner material 8b, it is preferable that the inner material 8b is arrange | positioned in the center vicinity between the bundle members 8c.

  Further, when the heat transfer promoting member 8 is composed of the bundling member 8c and the baffle material 8a, it is preferable to be the same as the inner material 8b, although not shown. Here, it is preferable to arrange a predetermined number of baffle members 8a in a region of 1 to 50 mm between the bundling members 8c. If the area is less than 1 mm, turbulent flow is unlikely to occur in the first heat medium W, and if the area exceeds 50 mm, the pressure loss tends to increase.

  Next, FIG. 8 shows a fourth embodiment of the composite heat transfer tube of the present invention. As shown in FIG. 8, the composite heat transfer tube 1 c is formed with the concavo-convex portion 19 in the large-diameter tube 2 of the composite heat transfer tube 1 of the first or second embodiment in at least a partial region S of the entire length. . Here, the same code | symbol is attached | subjected to the structure same as the composite heat exchanger tube 1, 1a of 1st or 2nd embodiment, and description is abbreviate | omitted. Moreover, although not shown in figure, you may arrange | position the above-mentioned heat-transfer promotion member 8 (refer FIG. 6, FIG. 7) in the outer side flow path 7. FIG.

(Uneven portion)
The concavo-convex portion 19 is preferably formed, for example, by processing the large-diameter tube 2 into a corrugated shape so that the height h of the convex portion is 0.5 to 2 mm and the pitch p of the convex portion is 5 to 20 mm. When the portion (height h and pitch p) is less than the above range, the uneven portion 19 is difficult to be formed, and when the convex portion exceeds the range, the pressure loss of the first heat medium W tends to increase. Moreover, the uneven | corrugated | grooved part 19 is the large diameter pipe corresponding to the area | region S where the temperature of the 2nd heat medium X which flows through the inside of an inner pipe satisfies the tolerance | permissible_range of 20-80 degreeC similarly to the said heat transfer promotion member 8. 2 is preferable. And the form of the uneven | corrugated | grooved part 19 is not limited to the said corrugated shape, if a turbulent flow generate | occur | produces in the 1st heat medium W in the outer side flow path 7, and a pressure loss does not become large, For example, said pipe inner surface An internally grooved tube in which a groove parallel to the tube axis direction or a spiral groove is formed in at least a part of the tube.

  Next, the example which used one of the composite heat exchanger tubes of this invention for the heat pump for water heaters is demonstrated. FIG. 9 shows an example in which the heat pump unit 24 is used in the water heater 30. The composite heat transfer tubes 1, 1a, 1b, 1c of the present invention can be used in the heat exchange portion of the heat pump unit 24. Water (first heat medium) is circulated through the large diameter tube 2 of the composite heat transfer tube 1, and carbon dioxide refrigerant (second heat medium) is circulated through the small diameter tube 3. The carbon dioxide refrigerant (second heat medium) absorbs atmospheric heat in the evaporator 25, is then compressed by the compressor 26, and is sent to the small-diameter tubes 3 of the composite heat transfer tubes 1, 1a, 1b, and 1c as a high-temperature and high-pressure fluid. It is done. The composite heat transfer tubes 1, 1 a, 1 b, 1 c exchange heat with the water (first heat medium) in the large-diameter tube 2 to form a low-temperature fluid, which is sent to the expansion valve 27. It expands by the expansion valve 27 and absorbs heat again by the evaporator 25. On the other hand, the low-temperature water (first heat medium) supplied from the hot water storage tank 28 (tank 29) by the pump P enters the large-diameter pipe 2 of the composite heat transfer pipes 1, 1a, 1b, 1c and comes into contact with the small-diameter pipe 3. As a result, it is heated to return to the hot water storage tank 28 (tank 29) as high-temperature water (first heat medium). Thus, since the composite heat exchanger tubes 1, 1a, 1b, and 1c of the present invention have excellent heat transfer performance, they are preferably used in the heat exchange portion of the carbon dioxide refrigerant heat pump hot water heater 30.

Examples of the present invention will be specifically described below.
As Examples 1 and 2, four small-diameter pipes 3 (see FIG. 5A) are provided in the large-diameter pipe 2 along the pipe axis direction, and FIG. 1 (winding shape 1: Example 1), FIG. 3 (a) (winding shape 2: Example 2) A composite heat transfer tube 1a in which a spiral winding portion 9 was formed on a large-diameter tube 2 was produced. Each configuration is as follows.

(1) Large-diameter pipe As the large-diameter pipe 2, a smooth pipe having an outer diameter of 12.7 mm, an inner diameter of 10.9 mm, and an overall length of 6700 m made of phosphorus deoxidized copper having an alloy number of C1220 defined in JISH3300 was used.
(2) Small-diameter pipe As shown in FIG. 5 (a), as the small-diameter pipe 3, the outer pipe 4 is inserted by inserting the inner pipe 5 (smooth pipe) into the outer pipe 4 (inner grooved pipe) and emptying it. The inner tube 5 was caulked, and a double tube in which a space 6 (tube axis orthogonal cross-sectional area: 0.97 mm ² ) was formed between the outer tube 4 and the inner tube 5 was used. In addition, as shown to Fig.5 (a), the four small diameter pipe | tubes 3 have been arrange | positioned so that the outer side flow path 7 inside the large diameter pipe | tube 2 may be divided | segmented equally. Also, the outer tube 4 and the inner tube 4 are arranged so that the ratio of the cross-sectional area of one small-diameter tube 3 to the cross-sectional area of the outer channel 7 (outer channel / small-diameter tube) in the tube axis orthogonal section is about 15. Tube 5 was set up.
(Outer pipe)
As the outer tube 4, an internally grooved tube having an outer diameter of 4.0 mm, an inner diameter of 3.0 mm, and a total length of 6700 m made of phosphorous deoxidized copper having an alloy number of C1220 specified in JISH3300 was used. As the groove shape, the number of grooves is 40, the groove lead angle (angle formed by the outer tube axis and the groove) is 0 °, the height of the fin formed between the grooves is 0.2 mm, the peak angle of the fin is 20 °, the fin pitch is 0 .23 mm.
(Inner pipe)
As the inner pipe 5, a smooth pipe having an outer diameter of 3.0 mm, an inner diameter of 2.0 mm, and a total length of 6700 m made of phosphorus deoxidized copper having an alloy number of C1220 defined in JISH3300 was used.

(3) Winding portion The large-diameter tube 2 has a spiral shape with a maximum outer diameter OD186.2 mm and a minimum inner diameter ID 84.6 mm as shown in FIG. 1 (winding shape 1) and FIG. 3 (a) (winding shape 2). The winding part 9 was formed in two layers. The height H of the winding part 9 was 25.7 mm.

(Winding shape 1: Example 1)
The radius of the quarter circle of the curved path 11 on each circumference (9a, 9b, 9c, 9d) of the winding portion 9 is 40 mm, 52.7 mm, 65.4 mm, 78.1 mm from the innermost circumference 9a to the outermost circumference 9d. It was connected in a straight line 10 with a long side length of 300 mm, a short side length of 30 mm, and a 42.7 mm length, and wound so that the large-diameter tubes 2 of each circumference were in contact with each other. Further, the large-diameter pipes 2 of the respective stages (9A, 9B) of the winding part 9 are brought into contact with each other, and both pipe end portions 2a, 2b of the large-diameter pipe 2 are located inside the inner part (the innermost circumference 9a). Formed.

(Winding shape 2: Example 2)
The radius of the quarter circle of the curved path 11 of the winding portion 9 is the outermost periphery 9d, the adjacent periphery 9c is 52.7 mm, 65.4 mm, and the other periphery is 40 mm, and the length of the long side portion is 338.1 mm. , 312.7 mm, 325.4 mm, 300 mm, and short side lengths 68.1 mm, 42.7 mm, and 80.8 mm, 55.4 mm, 30 mm, and a straight path 10, the outermost periphery 9d and its It wound so that the large diameter pipe | tubes 2 of the adjacent periphery 9c contact | abutted, and the clearance gap part 13 might be formed between the large diameter pipe | tubes 2 of the other periphery. Further, the large-diameter pipes 2 of the respective stages (9A, 9B) of the winding part 9 are brought into contact with each other, and both pipe end portions 2a, 2b of the large-diameter pipe 2 are located inside the inner part (the innermost circumference 9a). Formed.

  Further, as Comparative Example 1, a composite heat transfer tube 51 in which a spiral winding part 53 as shown in FIG. 11A (winding shape 3) was formed was produced. And it was made to be the same as that of the composite heat exchanger tube (winding shape 1) 1a of Example 1 except having formed both the pipe end parts 52a and 52b of the large diameter pipe | tube 52 in the outermost periphery (outer side) of the winding part 53. FIG. In addition, the length of the short side part of the straight path 10 of the winding part 53 will be 30 mm and 17.3 mm.

  Using the produced composite heat transfer tubes 1a and 51 (Examples 1 and 2 and Comparative Example 1), a heat insulating case 15 for housing each composite heat transfer tube 1a and 51 is prepared, and the area of each heat insulating case 15 is measured. did. Here, the clearances of the composite heat transfer tubes 1a and 51 in the heat insulating case 15 are all the same. Table 1 shows the area ratio of the heat insulating case 15 of Examples 1 and 2 when the area of the heat insulating case 15 of the composite heat transfer tube 51 (Comparative Example 1) is 100.

  As shown in Table 1, the heat insulation case 15 of Examples 1 and 2 has a smaller area than the heat insulation case 15 of Comparative Example 1. Therefore, it was confirmed that the composite heat transfer tube 1a of Examples 1 and 2 has a smaller volume occupied by the composite heat transfer tube 1a than the composite heat transfer tube 51 of Comparative Example 1.

It is a top view which shows the structure of the composite heat exchanger tube which concerns on this invention. (A) is the sectional view on the AA line of FIG. 1, (b) is the sectional view on the BB line, the description of the small diameter pipe is omitted, and (c) is an enlarged sectional view of the large diameter pipe. (A) is a top view which shows the other form of a winding part, (b) is CC sectional view taken on the line of (a), and description of a small diameter pipe is abbreviate | omitted. (A) is a top view which shows the other form of a winding part, (b) is a schematic diagram which shows the state which accumulated the unit in parallel, (c), (d) is a schematic diagram which shows the state accumulated in series is there. (A) is a pipe axis orthogonal cross-sectional view of a large-diameter pipe of another embodiment of the composite heat transfer pipe, and (b) is an enlarged cross-sectional view of the small-diameter pipe of (a). It is a partially broken perspective view which shows the structure of the composite heat exchanger tube with which the baffle material is arrange | positioned. It is a partially broken perspective view which shows the structure of the composite heat exchanger tube with which the bundle member and the inner material are arrange | positioned. The composite heat exchanger tube in which the uneven | corrugated | grooved part was formed is shown, (a) is a partially broken side view, (b) is the DD sectional view taken on the line of (a). It is explanatory drawing which shows typically the structure of the water heater using a composite heat exchanger tube. It is a perspective view which shows the structure of the conventional composite heat exchanger tube. (A) is a top view which shows the structure of the conventional composite heat exchanger tube, (b) is the EE sectional view taken on the line of (a), (c) is the FF sectional view taken on the line of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite heat exchanger tube 2 Large diameter pipe 2a, 2b Pipe end part 3 Small diameter pipe 7 Outer flow path 9 Winding part 9a circumference (innermost circumference)
9b, 9c circumference (adjacent circumference)
9d circumference (outermost circumference)
X 2nd heat medium W 1st heat medium

Claims (8)

A large-diameter pipe, and an outer diameter smaller than the inner diameter of the large-diameter pipe, and a small-diameter pipe provided along the pipe axis direction inside the large-diameter pipe
A composite heat transfer tube having an outer flow path formed between the large-diameter pipe and the small-diameter pipe as a first heat medium flow path, and an inside of the small-diameter pipe as a second heat medium flow path,
The large-diameter pipe is formed in a spiral winding part at least a part of its entire length,
The winding part is stacked in an even number of stages, and the large-diameter pipe on the outermost periphery of the winding part is wound so as to abut on the large-diameter pipe on the adjacent circumference adjacent to the outermost periphery, and the A composite heat transfer tube characterized in that both end portions of the large-diameter tube are formed on the innermost periphery of the winding portion.   The winding portion has the large-diameter tube at each stage in contact with the large-diameter tube at the adjacent stage, and the large-diameter tube at each circumference of the winding portion contacts the large-diameter tube at the adjacent circumference. The composite heat transfer tube according to claim 1, wherein the composite heat transfer tube is formed as follows.   The said winding part is an oval shape which has a straight path and a curved path alternately in the plane where the winding shape orthogonally crosses with respect to a winding axis | shaft. Composite heat transfer tube.   The composite heat transfer tube according to any one of claims 1 to 3, wherein the both tube end portions are formed in the same direction.   The small-diameter pipe is composed of an outer pipe and an inner pipe provided coaxially inside the outer pipe and having an outer diameter smaller than the inner diameter of the outer pipe, and a space between the outer pipe and the inner pipe. The composite heat transfer tube according to any one of claims 1 to 4, wherein the composite heat transfer tube is a double tube in which a portion is formed.   The composite heat transfer tube according to any one of claims 1 to 5, wherein a direction in which the first heat medium flows and a direction in which the second heat medium flows are opposed to each other.   The composite heat transfer tube according to any one of claims 1 to 6, wherein the first heat medium is water, and the second heat medium is a refrigerant.   The composite heat transfer tube according to any one of claims 1 to 7, wherein at least one of the large-diameter tube and the small-diameter tube is made of copper or a copper alloy.

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