heat exchanger

Abstract

To achieve compactness of a heat exchanger having a spirally wound coil portion. [Solution] The heat exchanger (10) comprises at least a first double pipe (11) and a second double pipe (12) in which an inner pipe (2) and an outer pipe (1) are double-arranged. The first double pipe (11) has a first coil portion (21) wound in a spiral shape, and the first coil portion (21) is formed so as to expand from one end side to the other end side in the axial direction. The second double pipe (12) has a second coil portion (22) wound in a spiral shape, and the second coil portion (22) is formed so as to expand from one end side to the other end side in the axial direction. The second coil portion (22) expands in the same direction as the first coil portion (21), and is positioned inside the first coil portion (21) with one end of the second coil portion (22) shifted toward the other end side of the first coil portion (21) relative to one end of the first coil portion (21). In each of the first double pipe (11) and second double pipe (12), heat exchange takes place between the fluid flowing in the inner pipe (2) and the fluid flowing between the outer pipe (1) and the inner pipe (2).

Description

[Technical Field]

[0001] The present invention relates to a heat exchanger or the like having a spirally wound coil portion. [Background technology]

[0002] Heat exchangers having a spirally wound coil portion have been known for some time. Patent Document 1 describes an exhaust heat recovery system that performs heat exchange using a heat transfer tube having first to fourth heat transfer portions formed in approximately the same shape as a conical spiral, as this type of heat exchanger. In this exhaust heat recovery system, the conical spiral portion of the heat transfer tube is disposed within a casing that constitutes part of a chimney structure for discharging exhaust gas from a combustion engine such as a boiler. The heat transfer tube is configured so that a liquid flows through it, and the liquid exchanges heat with the exhaust gas flowing within the casing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3176771 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional heat exchangers, one fluid that exchanges heat flows through a casing, and the casing houses a coil of a heat transfer tube through which the other fluid flows. The casing must be large enough to accommodate the multiple coils. Furthermore, the cross-sectional flow areas of the inlet and outlet of the casing are large, and the connections between the inlet and outlet are also relatively large. This can result in a large heat exchanger.

[0005] The present invention has been made in view of the above circumstances, and has an object to realize a compact heat exchanger having a spirally wound coil portion. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a first invention is a heat exchanger comprising at least a first double pipe and a second double pipe, each having an inner pipe and an outer pipe in a double configuration, wherein the first double pipe has a first coil portion wound in a spiral shape, and the first coil portion is formed so as to expand from one end side to the other end side in its axial direction, and the second double pipe has a second coil portion wound in a spiral shape, and the second coil portion is formed so as to expand from one end side to the other end side in its axial direction, and the second coil portion expands in the same direction as the first coil portion, and is positioned inside the first coil portion with one end of the second coil portion shifted toward the other end side of the first coil portion relative to one end of the first coil portion, and in each of the first double pipe and the second double pipe, heat exchange occurs between a fluid flowing through the inner pipe and a fluid flowing between the outer pipe and the inner pipe. is.

[0007] In a second aspect of the present invention, in the first aspect, in each of the first coil portion and the second coil portion, adjacent winding portions of one turn in the axial direction are spaced apart from each other.

[0008] A third aspect of the present invention is the first aspect of the present invention, wherein each of the first coil portion and the second coil portion has one turn adjacent to each other in the axial direction as a winding portion, The first turn of the second coil portion at one end thereof contacts from the inside with the second turn and subsequent turns from one end of the first coil portion.

[0009] The fourth invention is the first invention, further comprising an outer pipe collector pipe connected to one end of each of the first double pipe and the second double pipe, the outer pipe collector pipe communicating with the flow path between the outer pipe and the inner pipe and through which the inner pipe passes.

[0010] The fifth invention is the fourth invention, further comprising an inner pipe collector connected to one end of each of the first double pipe and the second double pipe so as to communicate with a flow path of an inner pipe that penetrates the outer pipe collector and protrudes from the outer surface of the outer pipe collector.

[0011] A sixth aspect of the present invention is the coil winding coil according to the first aspect of the present invention, wherein a spiral spacer is provided between the outer tube and the inner tube in each of the first coil portion and the second coil portion. [Effects of the Invention]

[0012] The present invention provides a heat exchanger including at least a first double-pipe and a second double-pipe. Each double-pipe has a spirally wound coil portion that expands from one end toward the other end in the axial direction. The second coil portion of the second double-pipe expands in the same direction as the first coil portion of the first double-pipe and is disposed inside the first coil portion, with one end of the second coil portion shifted toward the other end of the first coil portion relative to one end of the first coil portion. In other words, at least a portion of the second coil portion is disposed inside the first coil portion. This reduces the space occupied by the first and second coil portions. Furthermore, in each double-pipe, heat is exchanged between a fluid flowing through the inner pipe and a fluid flowing between the outer and inner pipes. Therefore, unlike conventional heat exchangers, a casing large enough to accommodate the first and second coil portions is not required. According to the present invention, a compact heat exchanger having a spirally wound coil portion can be realized. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a heat exchanger according to an embodiment. [Figure 2] FIG. 2 is a top view of the heat exchanger according to the embodiment, illustrating a partial cross section of a double pipe. [Figure 3] FIG. 3 is a perspective view of a straight portion of a double pipe in a heat exchanger according to an embodiment, with the outer pipe omitted. [Figure 4] FIG. 4 is a perspective view of one double pipe constituting the heat exchanger according to the embodiment. [Figure 5]Figure 5A is a cross-sectional view of an outer pipe collecting pipe and an inner pipe collecting pipe provided for one end side pipe section in a heat exchanger according to an embodiment, when a fluid is heated; Figure 5B is a cross-sectional view of an outer pipe collecting pipe and an inner pipe collecting pipe provided for the other end side pipe section in a heat exchanger, when a fluid is heated; Figure 5C is a cross-sectional view of an outer pipe collecting pipe and an inner pipe collecting pipe provided for one end side pipe section, when a fluid is cooled; and Figure 5B is a cross-sectional view of an outer pipe collecting pipe and an inner pipe collecting pipe provided for the other end side pipe section, when a fluid is cooled. [Figure 6] FIG. 6 is a schematic vertical cross-sectional view of the heat exchanger for explaining the arrangement of the coil portion. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are merely examples of the present invention and are not intended to limit the scope of the present invention, its applications, or its uses.

[0015] This embodiment is a heat exchanger 10 equipped with a plurality of double pipes that are independent of each other. The heat exchanger 10 shown in Fig. 1 is equipped with a first double pipe 11, a second double pipe 12, a third double pipe 13, a fourth double pipe 14, and a fifth double pipe 15. The number of double pipes in the heat exchanger 10 is not particularly limited as long as it is two or more. In Fig. 1, the first double pipe 11, the third double pipe 13, and the fifth double pipe 15 are colored to make it easier to identify each of the double pipes 11 to 15.

[0016] The double pipes 11 to 15 have the same shape and size, and each of the double pipes 11 to 15 has a constant outer diameter (thickness) along its length.

[0017] As shown in Fig. 2, in a cross-sectional view, each of the double pipes 11 to 15 includes an outer pipe 1 and an inner pipe 2 disposed inside the outer pipe 1. In Fig. 2, the cross sections of the double pipes 11 to 15 are partially shown.

[0018] Each of the double pipes 11-15 has an outer flow passage 5 formed between the inner surface of the outer pipe 1 and the outer surface of the inner pipe 2, and an inner flow passage 6 formed inside the inner pipe 2. In each of the double pipes 11-15, heat exchange occurs between a fluid (gas or liquid) flowing through the outer flow passage 5 and a fluid (gas or liquid) flowing through the inner flow passage 6. In each of the double pipes 11-15, the fluid flows in the outer flow passage 5 and the inner flow passage 6 in opposite directions.

[0019] A spacer 3 shown in FIG. 3 is provided between the outer pipe 1 and the inner pipe 2. FIG. 3 is a perspective view of the double pipes 11-15 (straight portions of the double pipes 11-15) with the outer pipe 1 omitted. The spacer 3 is a wire wound in a spiral shape at a relatively large pitch around the outer surface of the inner pipe 2. The spacer 3 is provided over the entire length of the double pipes 11-15. This makes the distance between the inner surface of the outer pipe 1 and the outer surface of the inner pipe 2 constant over the entire length of the double pipes 11-15, and the outer flow passage 5 is formed in a spiral shape in the double pipes 11-15. This allows for efficient heat exchange between the fluid in the outer flow passage 5 and the fluid in the inner flow passage 6.

[0020] As shown in Fig. 4, each of the double pipes 11 to 15 includes coil portions 21 to 25 wound in a spiral shape around an axis A (see Fig. 2) extending vertically, one-end pipe portions 31 to 35 continuing to one end of the coil portions 21 to 25, and other-end pipe portions 41 to 45 continuing to the other end of the coil portions 21 to 25. The coil portion 21 of the first double pipe 11 will be referred to as the "first coil portion," the coil portion 22 of the second double pipe 12 as the "second coil portion," the coil portion 23 of the third double pipe 13 as the "third coil portion," the coil portion 24 of the fourth double pipe 14 as the "fourth coil portion," and the coil portion 25 of the fifth double pipe 15 as the "fifth coil portion."

[0021] The one-end pipe sections 31-35 and the other-end pipe sections 41-45 each extend straight. However, the one-end pipe sections 31-35 and the other-end pipe sections 41-45 may be curved. In this embodiment, the one-end pipe sections 31-35 are provided above the coil sections 21-25 in the axial direction, and the other-end pipe sections 41-45 are provided below. However, the one-end pipe sections 31-35 may be provided below the coil sections 21-25 in the axial direction, and the other-end pipe sections 41-45 may be provided above. In other words, the heat exchanger 10 may be configured so that the coil sections 21-25 widen upward.

[0022] As shown in Fig. 4, the coil portions 21-25 are formed so as to widen from one end to the other end in the axial direction of the spiral. In the coil portions 21-25, adjacent "one-turn winding portions" in the axial direction are spaced apart from each other. The axial pitches P, P' (see Fig. 6) of the coil portions 21-25 are larger than the outer diameter d (see Fig. 2) of each of the double pipes 11-15.

[0023] In this embodiment, the multiple coil portions 21-25 are arranged coaxially with one another. Furthermore, when viewed from above, the multiple coil portions 21-25 are arranged so that the one-end side pipe portions 31-35 overlap one another and the other-end side pipe portions 41-45 also overlap one another. The multiple one-end side pipe portions 31-35 extend in the same direction, and the multiple other-end side pipe portions 41-45 also extend in the same direction. The one-end side pipe portions 31-35 and the other-end side pipe portions 41-45 are arranged parallel to one another (see FIG. 2).

[0024] Furthermore, the first turn of the second coil portion 22 at one end thereof contacts from the inside with the second turn of the first coil portion 21 from one end. Note that the first turn of the third coil portion 23 at one end thereof may also contact from the inside with the second turn of the first coil portion 21 from one end.

[0025] The heat exchanger 10 includes an outer pipe collecting pipe 16 and an inner pipe collecting pipe 17 provided for the one end side pipe portions 31 to 35, and an outer pipe collecting pipe 26 and an inner pipe collecting pipe 27 provided for the other end side pipe portions 41 to 45. Although not shown, the outer pipe collecting pipe 16, the inner pipe collecting pipe 17, the outer pipe collecting pipe 26, and the inner pipe collecting pipe 27 are each connected to a pipe leading to a fluid supply source or a fluid discharge destination.

[0026] The outer collecting pipe 16 and the inner collecting pipe 17 are both pipes that extend in the vertical direction (the arrangement direction of the one-end pipe sections 31-35). As shown in FIGS. 5A and 5C , the open ends of the outer pipes 1 of the multiple one-end pipe sections 31-35 are connected to the outer collecting pipe 16 at vertical intervals, and the inner pipes 2 of the multiple one-end pipe sections 31-35 pass through the outer collecting pipe 16. The inner pipes 2 of the one-end pipe sections 31-35 protrude from the outer surface of the outer collecting pipe 16. The open ends of the inner pipes 2 of the multiple one-end pipe sections 31-35 are connected to the inner collecting pipe 17 at vertical intervals. The outer collecting pipe 16 is connected to the outer flow paths 5 of each of the one-end pipe sections 31-35, and the inner collecting pipe 17 is connected to the inner flow paths 6 of each of the one-end pipe sections 31-35.

[0027] The outer collecting pipe 26 and the inner collecting pipe 27 are both pipes that extend vertically (in the arrangement direction of the other-end pipe sections 41-45). As shown in FIGS. 5B and 5D , the open ends of the outer pipes 1 of the multiple other-end pipe sections 41-45 are connected to the outer collecting pipe 26 at vertical intervals, and the inner pipes 2 of the multiple other-end pipe sections 41-45 pass through the outer collecting pipe 26. The inner pipes 2 of the multiple other-end pipe sections 41-45 protrude from the outer surface of the outer collecting pipe 26. The open ends of the inner pipes 2 of the multiple other-end pipe sections 41-45 are connected to the inner collecting pipe 27 at vertical intervals. The outer collecting pipe 26 is connected to the outer flow paths 5 of each of the other-end pipe sections 41-45, and the inner collecting pipe 27 is connected to the inner flow paths 6 of each of the other-end pipe sections 41-45.

[0028] In the heat exchanger 10, a fluid to be heated or a fluid to be cooled flows through the inner flow path 6. When the fluid in the inner flow path 6 is heated, for example, the fluid to be heated (liquid) flows in the inner flow path 6 from the other end side pipe sections 41-45 toward the one end side pipe sections 31-35, while a high-temperature fluid (gas) that heats the fluid in the inner flow path 6 flows in the outer flow path 5 from the one end side pipe sections 31-35 toward the other end side pipe sections 41-45 (see FIGS. 5(A) and 5(B)).

[0029] Furthermore, when cooling the fluid in the inner flow path 6, for example, the fluid (liquid) to be cooled flows in the inner flow path 6 from the one end side pipe sections 31-35 to the other end side pipe sections 41-45, while the low-temperature fluid (liquid) that cools the fluid in the inner flow path 6 flows in the outer flow path 5 from the other end side pipe sections 41-45 to the one end side pipe sections 31-35 (see Figures 5(C) and 5(D)).

[0030] [About the coil placement] The arrangement of the coil section will be described using the heat exchanger 110 shown in Fig. 6 as an example. Fig. 6 is a schematic longitudinal cross-sectional view of the coil sections 21-23 of a heat exchanger 110 different from that shown in Fig. 1, cut vertically through the axis A. In Fig. 6, the inner pipe 2 of each double pipe 11-13 is omitted, and the pipe sections of the same double pipe 11-13 are connected by a dashed dotted line between the centers of their cross sections. Note that the "pipe section" in Fig. 6 refers to the circular portion representing the cross-sectional shape of the double pipe 11-13.

[0031] The heat exchanger 110 shown in Fig. 6 includes a first double pipe 11, a second double pipe 12, and a third double pipe 13. In each of the coil sections 21-23 of the heat exchanger 110, on one side of the axis A (the left or right side in Fig. 6), all pipe sections belonging to the same double pipe 11-13 are aligned in a substantially straight line along a dashed line X extending diagonally. The coil sections 21-25 are substantially truncated cones. In each of the coil sections 21-23, in cross section, from the second turn onwards, a plurality of turns (portions equivalent to one turn) are provided at a constant pitch P in the axial direction (vertical direction). The radius R of the outer surface of the n-th turn is n and the radius of the outer surface of the (n+1)th turn, R n+1The difference between these is approximately equal to the outer diameter d of the tubular portion (n is a natural number). The pitch P' between the first winding and the second winding is larger than the pitch P of the second winding and thereafter.

[0032] Regarding the arrangement of the multiple coil portions 21 to 23, the second coil portion 22 extends in the same direction as the first coil portion 21, and is arranged inside the first coil portion 21 with one end of the second coil portion 22 shifted toward the other end in the axial direction from one end (the upper end in FIG. 6) of the first coil portion 21. The third coil portion 23 extends in the same direction as the second coil portion 22, and is arranged inside the second coil portion 22 with one end of the third coil portion 23 shifted toward the other end in the axial direction from one end of the second coil portion 22.

[0033] The second double pipe 12 is assembled to the first double pipe 11 by rotating the second coil portion 22 around the first coil portion 21. The third double pipe 13 is assembled to the second double pipe 12 by rotating the third coil portion 23 around the second coil portion 22. The coil portions 21 to 23 may be integrated together by wrapping a fixing means (not shown) such as a band around the locations where the pipe portions come into contact with each other.

[0034] In the heat exchanger 110, one end of the second coil section 22 is shifted by half a pitch toward the other end in the axial direction relative to one end of the first coil section 21, and one end of the third coil section 23 is shifted by half a pitch toward the other end in the axial direction relative to one end of the second coil section 22.

[0035] [Effects of the embodiment] This embodiment is a heat exchanger 10, 110 equipped with multiple double pipes. Each double pipe has a spirally wound coil portion that widens from one end to the other end in the axial direction. Inside the first coil portion 21, other coil portions are arranged in order from one end to the other end. This reduces the space occupied by the multiple coil portions. Furthermore, in each double pipe, heat exchange occurs between the fluid flowing through the inner flow path 6 and the fluid flowing through the outer flow path 5. Therefore, unlike conventional heat exchangers, a casing large enough to accommodate multiple coil portions is not required. This embodiment makes it possible to achieve a compact heat exchanger 10, 110 having spirally wound coil portions.

[0036] Furthermore, in conventional heat exchangers, the coils of the heat transfer tubes are arranged inside the casing, so increasing the number of coils in the heat transfer tubes increases the pressure loss of the gas flowing through the casing. However, in this embodiment, there is no such restriction. Furthermore, the same double-walled tubes can be used. Therefore, the number of double-walled tubes used in the heat exchangers 10 and 110 can be easily increased, thereby increasing the flow rate of the heat exchanger 10.

[0037] [Other embodiments] In the above-described embodiment, the double pipe closest to one end is designated as the "first double pipe" and the double pipe immediately below it is designated as the "second double pipe." However, for any two double pipes in a plurality of double pipes, the double pipe closest to one end may be designated as the "first double pipe" and the double pipe closer to the other end may be designated as the "second double pipe."

[0038] In the above embodiment, the coil portions 21 to 25 have the same shape and size, but they may be different from one another.

[0039] In the above-described embodiment, the coil portions 21 to 25 are arranged coaxially with one another, but the axial centers of the coil portions 21 to 25 may be slightly offset from one another. [Industrial Applicability]

[0040] The present invention is applicable to a heat exchanger or the like having a spirally wound coil portion. [Explanation of symbols]

[0041] 1 outer tube 2 Inner tube 5 Outer channel 6 Inner flow path 10,110 Heat exchanger 11~15 double tube 11 1st double pipe 12 2nd double pipe 16,26 Collecting pipe for outer pipe 17,27 Collecting pipe for inner pipe 21~25 Coil section 21 First coil section 22 Second coil section 31~35 One end side pipe section 41~45 Other end side pipe section

Claims

1. A plurality of double pipes each having an inner pipe and an outer pipe provided in a double configuration are provided, Each of the plurality of double pipes has a spirally wound coil portion, and the coil portion is formed so as to expand from one end side to the other end side in the axial direction thereof, the plurality of coil sections extend in the same direction, and the remaining coil sections are arranged in order from the outside to the inside inside the outermost coil section; Among the plurality of coil portions, the more inner the coil portion, the closer its one end is to the other end, In at least some of the coil portions of the plurality of double pipes, the inner coil portion contacts the outer coil portion from the inside, A heat exchanger in which, in each of the plurality of double pipes, heat exchange occurs between a fluid flowing through the inner pipe and a fluid flowing between the outer pipe and the inner pipe.

2. The plurality of double pipes include a first double pipe having a first coil portion and a second double pipe having a second coil portion disposed inside the first coil portion; The heat exchanger according to claim 1 , wherein adjacent turns of the first coil portion and the second coil portion in the axial direction are spaced apart from each other.

3. The plurality of double pipes include a first double pipe having a first coil portion and a second double pipe having a second coil portion disposed inside the first coil portion; In each of the first coil portion and the second coil portion, one turn adjacent to each other in the axial direction is defined as a winding portion, 2. The heat exchanger according to claim 1, wherein the first turn of the second coil portion at one end thereof contacts the second or subsequent turn of the first coil portion from one end thereof from the inside.

4. The plurality of double pipes include a first double pipe having a first coil portion and a second double pipe having a second coil portion disposed inside the first coil portion; 2. The heat exchanger according to claim 1, further comprising an outer pipe collecting pipe connected to one end of each of the first double pipe and the second double pipe, the outer pipe collecting pipe communicating with a flow path between the outer pipe and the inner pipe and connected so that the inner pipe passes through.

5. 5. The heat exchanger according to claim 4, further comprising an inner pipe collector pipe connected to each of the one ends of the first double pipe and the second double pipe so as to communicate with a flow path of the inner pipe that penetrates the outer pipe collector pipe and protrudes from the outer surface of the outer pipe collector pipe.

6. The plurality of double pipes include a first double pipe having a first coil portion and a second double pipe having a second coil portion disposed inside the first coil portion; The heat exchanger according to claim 1 , wherein a spiral spacer is provided between the outer pipe and the inner pipe in each of the first coil portion and the second coil portion.

Images