JP2008298325A - Heat exchanger and water heating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of achieving high heat exchanging efficiency while minimizing a case even when a discharge port of a heating medium is formed on a peripheral wall portion of the case surrounding a spiral tubular body portion of a heat transfer tube. <P>SOLUTION: This heat exchanger B provided with the discharge port 71 for discharging the heating medium, on the peripheral wall portion such as a front wall portion 70c of the case 7 surrounding the spiral tubular body portion 5 of the heat transfer tube P, further comprises a guide portion 8 formed in a state of projecting into a spatial portion 79 inside of the spiral tubular body portion 5 for supplying the heating medium to the inside from the outside. A part at a side opposite to the discharge port 71, of the guide portion 8 is provided with a heating medium passing port 81, and the heating medium passing through the passing port 81 moves toward a part of the region at a side opposite to the discharge port 71 of the circumference of the guide portion 8, and then moves to the other region of the circumference toward the discharge port 71. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat exchanger for recovering heat from a heating medium such as combustion gas using a so-called spiral heat transfer tube and heating a desired fluid such as water, and a hot water apparatus provided with the heat exchanger About.

  Conventional examples of heat exchangers using so-called helical heat transfer tubes include those described in Patent Documents 1 and 2. In the heat exchangers described in these documents, a helical tube part of one or a plurality of heat transfer tubes is accommodated in a case, and a combustor is disposed in an inner space of the helical tube part. The combustion gas generated by the is supplied. The spiral tube portion has a configuration in which, for example, a plurality of hollow circular loop portions are connected in series and arranged in a fixed direction with a gap therebetween, and an inner space portion of the spiral tube portion The combustion gas supplied to the gas passes through the gap between the helical tube portions and flows out to the entire outer periphery of the helical tube portion. According to the heat exchanger having such a configuration, the combustion gas can be efficiently applied to the entire peripheral region of the spiral tubular body portion, and high heat exchange efficiency can be obtained.

  However, the prior art sometimes has problems as described below.

  In other words, the heat exchanger case is formed with an exhaust port for exhausting the combustion gas after heat recovery to the outside. The exhaust port has a heat exchanger installation condition and other various conditions. In consideration of this, there is a case where it is desired to provide the peripheral wall portion surrounding the periphery of the spiral tubular body portion such as the front surface portion or the rear surface portion of the case. On the other hand, the conventional technology is configured such that the combustion gas supplied to the inner space of the spiral tube portion proceeds all at once toward the entire outer periphery of the spiral tube portion. ing. Therefore, in this prior art, in order to discharge the combustion gas from the discharge port provided in the peripheral wall portion of the case, the combustion gas dispersed around the entire outer periphery of the helical tube portion is a certain region in the case. It is necessary to separately provide a combustion gas passage in the case for guiding the gas to the discharge port after being assembled in the case. As a result, the case increases in size. From the viewpoint of promoting the downsizing of the entire heat exchanger, it is desirable that such a problem be suitably eliminated. In addition, without providing the combustion gas passage as described above in the case, the combustion gas supplied to the inner space of the spiral tubular body is simply provided in the peripheral wall of the case. Failure to reduce heat exchange efficiency because the portion close to the discharge port of the gap in the spiral tube portion passes intensively and does not pass evenly through the gap around the entire circumference of the spiral tube portion. Invite.

JP 2007-46794 A JP-T-2006-503260

The present invention has been conceived under the circumstances as described above, and is a case where the discharge port of the heating medium is provided in the peripheral wall portion of the case surrounding the helical tube portion of the heat transfer tube. However, it is an object of the present invention to provide a heat exchanger capable of obtaining high heat exchange efficiency while reducing the size of the case, and a hot water device including the heat exchanger.

  In order to solve the above problems, the present invention takes the following technical means.

  The heat exchanger provided by the first aspect of the present invention has one or a plurality of heat transfer tubes having a helical tube portion, a peripheral wall portion surrounding the periphery of the helical tube portion, and the peripheral wall. A heat exchanger having a discharge port for a heating medium in a part, the heat exchanger being provided to enter an inner space of the spiral tubular body part and for heating An internal hollow guide portion capable of supplying the medium to the inside is provided, and the guide portion is supplied into the guide portion at a position opposite to the discharge port across the center. A passage port for allowing the heating medium to pass therethrough is provided, and the heating medium that has passed through the passage port is directed toward a part of the periphery of the guide portion on the side opposite to the discharge port. After proceeding, it is configured to travel through the other surrounding areas toward the outlet. It is characterized in that there.

  According to such a configuration, the following effects can be obtained. That is, the heating medium supplied to the inside of the guide portion and passed through the passage opening of the guide portion is the region on the side opposite to the discharge port in the region where the helical tube portion around the guide portion is provided. After proceeding to a part of the area, it proceeds to another area and heads toward the discharge port. For this reason, a heating medium can be made to act suitably with respect to the perimeter area of a helical tube part, or a substantially perimeter area. As a result, it is possible to recover the heat effectively using the whole or substantially the entire helical tube body, and high heat exchange efficiency can be obtained. Further, in the present invention, the area itself around the guide portion is a passage for directly guiding the heating medium to the discharge port. For this reason, unlike the prior art, in addition to the region where the helical tube portion is provided, there is a passage for guiding the heating medium that has been dispersed and advanced around the helical tube portion to the discharge port. It is not necessary to provide it separately in the case. As a result, it is possible to reduce the size of the case and thus the overall heat exchanger. Further, in the present invention, the guide portion is provided in the inner space portion of the spiral tube portion, but this space portion is originally formed inward of the spiral tube portion, and is inherently Is a part that can become a dead space. In the present invention, since the guide portion is provided by effectively utilizing such a dead space, there is no problem that the case is enlarged due to the provision of the guide portion.

  In a preferred embodiment of the present invention, the case has first and second wall portions sandwiching the spiral tubular body portion in the axial length direction, and the guide portion is the first portion. The tip portion of the guide portion contacts or approaches the second wall portion, and the heating medium is prevented from passing through the portion between them. It is configured to be.

  According to such a configuration, in addition to being able to appropriately provide the guide portion using the first wall portion of the case, the heating medium that has passed through the guide portion and has passed around the guide portion. However, it is also preferable to pass between the front end portion of the guide portion and the second wall portion of the case and go to the discharge port as it is, which is more preferable for improving the heat exchange efficiency.

  In a preferred embodiment of the present invention, the substantially entire circumference of the outer peripheral surface of the guide portion and the substantially entire periphery of the inner peripheral surface of the spiral tubular body portion are configured to contact or approach each other.

  According to such a configuration, the gap between the outer peripheral surface of the guide portion and the inner peripheral surface of the spiral tube portion is eliminated or reduced, so that the combustion gas acts efficiently on the spiral tube portion. Will get. In particular, when the guide portion is brought into contact with the inner peripheral surface of the helical tube portion, the heat of the guide portion heated by the heating medium can be directly transmitted to the helical tube portion. The exchange efficiency can be further increased.

  In a preferred embodiment of the present invention, the helical tube portion has a configuration in which a plurality of loop portions are connected in series and arranged with a gap in the axial length direction. Each has a substantially oval shape or a substantially rectangular shape having a pair of straight tube portions extending in a fixed direction across the guide portion and a pair of curved tube portions connected to ends of the pair of straight tube portions. It is said that.

  According to such a configuration, by making each loop portion of the spiral tube portion into an elongated shape, the overall length of the spiral tube portion can be reduced without increasing the volume of the entire spiral tube portion. The heat transfer area can be increased by increasing the length. Therefore, it is more preferable to increase the heat exchange efficiency while reducing the size of the entire heat exchanger. Further, since the inner space portion of the spiral tube portion can be formed into a narrow shape, the inner portion of the spiral tube portion can be compared with the case where each loop portion is formed in a circular shape, for example. The volume of the space part and the size of the guide part arranged in the space part can be reduced, and the downsizing of the entire heat exchanger can be promoted.

  The hot water device provided by the second aspect of the present invention supplies the heat exchanger provided by the first aspect of the present invention and the combustion gas as the heating medium into the guide portion of the heat exchanger. And a combustor for performing the operation.

  According to such a configuration, the same effect as described for the heat exchanger provided by the first aspect of the present invention can be obtained.

  In a preferred embodiment of the present invention, a primary structure having a heat transfer tube configured separately from the heat exchanger and recovering heat from the combustion gas generated by the combustor and a case surrounding the heat transfer tube. A heat exchanger, and the heat exchanger is a secondary heat exchanger that recovers heat from the combustion gas after heat recovery by the primary heat exchanger, and these primary heat exchangers And the cases of the secondary heat exchanger are overlapped with each other, and an opening for inflow of combustion gas provided in the guide portion of the secondary heat exchanger communicates with the case of the primary heat exchanger. It has been configured.

  According to such a configuration, for example, sensible heat can be recovered from the combustion gas by the primary heat exchanger and latent heat can be recovered from the combustion gas by the secondary heat exchanger. Can be achieved. Further, the combustion gas recovered by the primary heat exchanger can be directly introduced from the case of the primary heat exchanger into the guide portion of the secondary heat exchanger. There is no need to separately use a dedicated member for advancing combustion gas from the exchanger to the secondary heat exchanger, and the overall configuration can be simplified.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 to 7 show an example of a hot water supply apparatus as a specific example of a hot water apparatus to which the present invention is applied, and a configuration related thereto. As clearly shown in FIG. 1, the hot water supply apparatus A of the present embodiment includes a combustor 3, a primary heat exchanger 1, and a secondary heat exchanger B. The secondary heat exchanger B corresponds to an example of a heat exchanger to which the present invention is applied.

  The combustor 3 is, for example, a positive combustion type gas burner, and is arranged in the burner case 30 and is configured such that fuel gas is supplied from the outside via a pipe 32. Combustion air is blown upward from the lower fan 31 into the burner case 30. The primary heat exchanger 1 is for recovering sensible heat from the combustion gas generated by the combustor 3, and the main part of the heat transfer tube 11 as a finned pipe having a plurality of fins 12 is in the case 10. It has a structure arranged in.

  The secondary heat exchanger B is for recovering latent heat from the combustion gas from which sensible heat has been recovered by the primary heat exchanger 1, and is provided at the upper part of the primary heat exchanger 1. The secondary heat exchanger B includes a case 7, a guide portion 8, a plurality of heat transfer pipes P, and a pair of headers 6A and 6B for entering and discharging hot water. Each of the plurality of heat transfer tubes P includes a spiral tube portion 5 and extended tube portions 51 and 52 connected to the lower end and the upper end of the spiral tube portion 5. The part 5 is accommodated in the case 7. In the present embodiment, the axial length direction of the spiral tubular body portion 5 (the direction in which the central axis C of the spiral tubular body portion 5 in FIG. 7 extends) is the vertical height direction (vertical direction) of the case 7.

  The case 7 has a hollow, substantially rectangular parallelepiped shape. As shown in FIG. 6, the front wall portion 70 c, the rear wall portion 70 d, and the side wall portions 70 e and 70 f are provided as peripheral wall portions surrounding the spiral tube body portion 5. Have. As shown in FIGS. 4 and 7, the case 7 has a bottom wall portion 70 a and an upper wall portion 70 b that sandwich the spiral tubular body portion 5 in the axial length direction. The bottom wall portion 70a and the upper wall portion 70b correspond to an example of the first and second wall portions referred to in the present invention. The front wall portion 70c of the case 7 is provided with a discharge port 71 for discharging the combustion gas that has entered the case 7 to the outside. On the other hand, as a means for flowing the combustion gas into the case 7, as shown in FIG. 4, a configuration in which an opening 80 is provided at the base end portion (lower end portion) of the guide portion 8 is adopted. Yes. The opening 80 communicates with the case 10 of the primary heat exchanger 1, and the combustion gas that has passed above the heat transfer tube 11 passes through the opening 80 and flows into the guide portion 8. . A specific configuration of the guide unit 8 will be described later.

  As shown in FIGS. 6 and 7, each of the helical tube portions 5 has a plurality of loop portions 50 each having a substantially oval shape in plan view and connected in series to each other through a plurality of gaps 59. It has the structure laminated | stacked on the direction (axial length direction). Among the loop portions 50, the straight tube portions 50a and 50b extending in the left-right width direction of the case 7 are horizontal, whereas the semicircular arc-shaped bent tube portions 50c and 50d connected to the end portions thereof. Is inclined up and down. Thus, if only the curved pipe parts 50c and 50d at both ends of the loop part 50 are inclined, compared with a case where the entire length region of the loop part 50 is formed as an inclined pipe part (in the case of a normal spiral), There is an advantage that the overall height of the spiral tubular body portion 5 can be kept low. The plurality of helical tube portions 5 are formed so that the sizes of the respective loop portions 50 are different from each other, and these are arranged in a substantially concentric overlapping shape. 7 shows a configuration in which a discharge port 73 is provided in the bottom wall portion 70a of the case 7. This occurs when latent heat is recovered from the combustion gas by the helical tube portion 5. FIG. This is a portion for discharging the drain (condensed water) to the outside of the case 7.

  The extended tube portions 51 and 52 connected to the lower and upper ends of the plurality of spiral tube portions 5 pass through the side wall portion 70e of the case 7 and are drawn to the outside of the case 7. The headers 6A and 6B for incoming and outgoing hot water are connected to the ends. The extended pipe part 51 is provided with a curved pipe part 51a for the purpose of improving water drainage when draining water from the spiral pipe part 5. As best shown in FIGS. 1 and 2, the outlet 60 </ b> B of the header 6 </ b> B is connected to the water inlet 11 a of the heat transfer tube 11 via an appropriate pipe 90. A water supply pipe (not shown) is connected to the water inlet 60A of the header 6A. The water supplied from the water supply pipe to the water inlet 60A is heated by sequentially passing through the plurality of helical tube portions 5 and the heat transfer pipe 11, and then supplied from the hot water outlet 11b to a desired hot water supply destination.

  The guide portion 8 is a portion for efficiently causing the combustion gas after the sensible heat recovery by the primary heat exchanger 1 to act on the plurality of helical tube portions 5 of the secondary heat exchanger B. . As shown in FIGS. 4 and 5, the guide portion 8 rises upward from the bottom wall portion 70 a of the case 7 and enters the inner space portion 79 of the spiral tubular body portion 5. It is hollow. The space portion 79 has a shape elongated in the left-right width direction of the case 7 (see FIG. 6), but the guide portion 8 has a flat three-dimensional shape corresponding to this, and the outer peripheral surface of the guide portion 8 is substantially omitted. The entire circumference and the substantially entire circumference of the inner circumferential surface of the innermost circumferential spiral tubular body portion 5 are configured to be close to each other with a minute gap therebetween. As a means for providing the guide portion 8, an internal hollow member 8 A for forming the guide portion 8 is formed by using, for example, a stainless steel metal plate, and this member 8 A is used as the bottom of the case 7. A means of inserting into the case 7 from the opening 70a ′ formed in the wall 70a and brazing to the bottom wall 70a is employed. However, unlike the present embodiment, the guide portion 8 can be formed integrally with the bottom wall portion 70 a of the case 7.

  In the peripheral wall portion of the guide portion 8, a passage port 81 is provided for allowing the combustion gas that has progressed into the guide portion 8 to pass therethrough. The passage port 8 has, for example, a rectangular shape, and is provided in a portion opposite to the combustion gas discharge port 71 with the center of the guide portion 8 interposed therebetween, so that the straight tubes of the plurality of spiral tubular body portions 5 are provided. It faces the portion 50a. Therefore, the combustion gas that has traveled into the guide portion 8 and passed through the passage port 81 travels toward the rear of the guide portion 8 as indicated by arrows N1 in FIG. The guide 8 is divided into left and right hands before reaching the discharge port 71. As shown in FIG. 4, the distal end (upper end) 82 of the guide portion 8 is in contact with the upper wall portion 70 b of the case 7, and the combustion gas is between the upper wall portion 70 b and the distal end portion 82. It is comprised so that the clearance gap to pass may not be produced.

  Next, the effect | action of the secondary heat exchanger B and the hot water supply apparatus A provided with this is demonstrated.

  First, when the combustor 3 is driven to generate combustion gas, sensible heat is recovered from the combustion gas by the primary heat exchanger 1. Next, the combustion gas flows into the guide portion 8 from the opening 80 of the guide portion 8 of the secondary heat exchanger B, and then passes through the passage port 81. As shown by arrows N1 to N4 in FIG. 6, the combustion gas that has passed through the passage port 81 is divided into two left and right hands around the guide portion 8 after traveling behind the guide portion 8 in the case 7. Proceeds and acts on the entire circumference of the plurality of spiral tubular body portions 5. That is, the combustion gas sequentially acts on the straight tube portion 50a, the curved tube portions 50c and 50d, and the straight tube portion 50b of each helical tube portion 5, and each helical tube portion 5 The whole is used for heat recovery. Therefore, the amount of latent heat recovered by the secondary heat exchanger B can be increased and the heat exchange efficiency can be increased.

  In particular, in the present embodiment, there is no gap between the front end portion 82 of the guide portion 8 and the upper wall portion 70b of the case 7, so that there is no loss through which the combustion gas passes through this portion. Further, since the gap between the outer peripheral surface of the guide portion 8 and the inner peripheral surface of the innermost spiral tube portion 5 is also reduced, when the combustion gas advances in the vicinity of the outer peripheral surface of the guide portion 8, This combustion gas can be efficiently applied to the innermost spiral tubular body portion 5. For this reason, it is possible to further improve the heat exchange efficiency.

  On the other hand, the region where the helical tube portion 5 around the guide portion 8 is provided is a passage for directing the combustion gas to the discharge port 71, and the combustion gas passing through this passage is the discharge port 71. To reach sequentially. For this reason, in the secondary heat exchanger B of the present embodiment, unlike the heat exchangers described in Patent Documents 1 and 2, the combustion gas dispersed in the region where the spiral tubular body portion 5 is provided. There is no need to separately provide a combustion gas passage in the case 7 for leading to the discharge port 71. As a result, the case 7 can be downsized. The guide portion 8 is provided by effectively using the inner space portion 79 of the spiral tubular body portion 5. The space portion 79 is a portion that can be a dead space in nature. Therefore, there is no problem that the entire size of the case 7 is increased by incorporating the guide portion 8 into the case 7.

  As described above, the primary heat exchanger 1 and the secondary heat exchanger B are connected such that their cases 10 and 7 are directly overlapped in the vertical direction. In addition, the combustion gas recovered by the primary heat exchanger 1 is configured to flow from the case 10 into the guide portion 8 as it is. For this reason, the overall height dimension of these two heat exchangers can be reduced, and there is no need to separately use a dedicated member for guiding the combustion gas from the primary heat exchanger 1 to the secondary heat exchanger B. Simplification of the overall configuration of the hot water supply apparatus A can also be achieved.

  8 and 9 show another embodiment of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment.

  In the embodiment shown in FIG. 8, the substantially entire circumference of the outer peripheral surface of the guide portion 8 and the substantially entire periphery of the inner peripheral surface of the innermost spiral tube portion 5 are in contact with each other. According to this embodiment, the heat of the guide part 8 can be directly transmitted to the innermost spiral tube part 5. That is, the guide portion 8 is heated to a relatively high temperature because combustion gas is introduced into the guide portion 8, but according to the present embodiment, the heat of the guide portion 8 is directly applied to the spiral tubular body portion 5. It is possible to transfer the heat and recover the heat by the spiral tubular body portion 5. Further, when the combustion gas travels around the guide portion 8 by an amount that does not cause a gap between the guide portion 8 and the innermost spiral tube portion 5, combustion occurs with respect to the spiral tube portion 5. The effect of working gas more efficiently can also be obtained.

  In the embodiment shown in FIG. 9, each loop portion 50 of the plurality of spiral tubular body portions 5 has a hollow circular shape in plan view. Correspondingly, the peripheral wall portion 70g of the case 7 surrounding the plurality of spiral tubular body portions 5 is substantially cylindrical, and the peripheral wall portion of the guide portion 8 is also substantially cylindrical. Thus, even if each loop part 50 of the spiral tubular body part 5 is formed in a hollow circular shape, the combustion gas flows through the guide part 8 as indicated by an arrow N1 ′ in FIG. After passing through the passage port 81, the combustion gas then travels through the entire area around the guide portion 8 as indicated by arrows N2 ′ to N4 ′, and is guided to the discharge port 71, and the same effect as in the above embodiment. Can be obtained. As understood from the present embodiment, in the present invention, the specific shape of each loop portion 50 of the spiral tubular body portion 5 is not limited, and various shapes can be employed. However, when the shape of the loop portion 50 is substantially oval in plan view or substantially rectangular in plan view as in the above embodiment, the width in the front-rear direction of the spiral tubular body portion 5 is reduced, By making the length in the left-right direction (longitudinal direction) of the spiral tubular body portion 5 relatively long, the heat transfer area of the spiral tubular body portion 5 can be increased. Moreover, since the space part 79 inside the spiral tubular body part 5 has a narrow shape, the size of the guide part 8 disposed in the space part 79 can be reduced. In the embodiment shown in FIG. 9, unlike the above embodiment, an opening 80 is provided at the upper end of the guide portion 8, and the upper wall 70b 'of the case 7 is the first wall referred to in the present invention. The bottom wall 70a ′ corresponds to the second wall portion in the present invention.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the heat exchanger and the hot water apparatus according to the present invention can be varied in design in various ways.

  As described above, the guide portion in the present invention may be provided in a state of being integral with or separate from the case. In addition, the guide portion is preferably formed in a shape and size substantially the same as the inner space portion of the spiral tubular body portion, but is not limited to this, and has a shape and a considerably different shape from the space portion. It does not matter if it is formed in size.

  The heat transfer tube is not limited to a posture in which the axial length direction of the spiral tubular body portion is substantially vertical, but may be a posture that is laid down so as to be in the horizontal direction, or a posture that is inclined obliquely, for example. The number of heat transfer tubes is not limited to a plurality, and the number of heat transfer tubes can be reduced to one by, for example, configuring the heat transfer tubes using flat tubes. As the fluid to be heated supplied to the heat transfer tube, an antifreeze liquid other than water or other fluid can be applied, and a medium other than the combustion gas can also be applied as a heating medium. The specific shape and material of the case are not particularly limited.

  In the embodiment described above, the heat exchanger according to the present invention is used as a secondary heat exchanger for recovering latent heat, but it is not limited to this. For example, the combustion gas generated by the combustor is directly supplied into the guide portion 8, and the sensible heat is recovered from the combustion gas, or both the sensible heat and the latent heat are recovered. You can also. If the heat transfer area of the spiral tube part 5 is increased to increase the amount of heat recovered by the spiral tube part 5, both sensible heat and latent heat can be recovered only by the heat exchanger according to the present invention. The hot water device as used in the present invention means a device having a function of generating hot water, and is used for various types of hot water supply devices for general hot water supply, bath hot water supply, heating, snow melting, and the like, and hot water supply. It is a concept that includes a wide range of equipment for producing hot water.

It is a schematic front sectional view showing an example of a hot water supply device as a hot water device to which the present invention is applied. It is a principal part front view of the hot-water supply apparatus shown in FIG. It is a left view of the secondary heat exchanger used for the hot-water supply apparatus shown in FIG. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. It is a plane sectional view of the secondary heat exchanger used for the hot-water supply apparatus shown in FIG. It is front sectional drawing of the secondary heat exchanger shown in FIG. It is principal part sectional drawing which shows the other example of this invention. (A) is a plane sectional view showing other examples of the present invention, and (b) is the front sectional view.

Explanation of symbols

A Hot water supply device (hot water device)
B Secondary heat exchanger (heat exchanger)
P Heat transfer tube 1 Primary heat exchanger 3 Combustor 5 Spiral tube portion 7 Case 8 Guide portion 50 Loop portion (of the spiral tube portion)
59 Clearance (of spiral tube)
79 Space (inside the spiral tube)
80 opening (of the guide)
81 Passage (for combustion gas in the guide)
82 Tip (of the guide)
70a Bottom wall (case)
70b Upper wall (case)
70c front wall (case peripheral wall)
71 outlet

Claims (6)

One or more heat transfer tubes having a helical tube section;
A case having a peripheral wall portion surrounding the periphery of the spiral tubular body portion, and a discharge port for the heating medium provided in the peripheral wall portion;
A heat exchanger comprising:
It is provided to enter an inner space of the spiral tube body, and has an internal cavity-shaped guide that can supply a heating medium to the inside.
Among the guide portions, a passage port for passing the heating medium supplied in the guide portion is provided at a position opposite to the discharge port across the center thereof,
The heating medium that has passed through the passage port proceeds toward a part of the periphery of the guide portion on the side opposite to the discharge port, and then proceeds to the other region around the guide portion. A heat exchanger configured to be directed to an outlet. The case has first and second wall portions sandwiching the spiral tubular body portion in the axial length direction, and the guide portion is directed from the first wall portion toward the space portion. Has entered,
The distal end portion of the guide portion is in contact with or close to the second wall portion, and is configured to prevent the heating medium from passing through a portion between them. Heat exchanger.   The heat exchanger according to claim 1 or 2, wherein a substantially entire circumference of the outer peripheral surface of the guide portion and a substantially entire circumference of the inner peripheral surface of the spiral tubular body portion are configured to contact or approach each other. . The helical tube portion has a configuration in which a plurality of loop portions are connected in series and arranged with a gap in the axial length direction,
Each of the plurality of loop parts has a pair of straight pipe parts extending in a certain direction across the guide part, and a pair of curved pipe parts connected to ends of the pair of straight pipe parts. The heat exchanger according to any one of claims 1 to 3, wherein the heat exchanger has a circular shape or a substantially long rectangular shape.   5. A heat exchanger according to claim 1, and a combustor for supplying combustion gas as the heating medium into the guide portion of the heat exchanger. A hot water device. A heat exchanger tube configured separately from the heat exchanger and performing heat recovery from the combustion gas generated by the combustor, and a primary heat exchanger having a case surrounding the heat exchanger tube;
The heat exchanger is a secondary heat exchanger that performs heat recovery from the combustion gas after heat recovery by the primary heat exchanger,
The cases of the primary heat exchanger and the secondary heat exchanger are overlapped with each other, and an opening for inflow of combustion gas provided in a guide portion of the secondary heat exchanger serves as the primary heat exchange. The hot water device according to claim 5, wherein the hot water device is configured to communicate with a case of the vessel.

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