JP4904965B2 - Heat exchanger and water heater - Google Patents

Description

  The present invention relates to a heat exchanger used for the purpose of recovering heat from a heating gas such as a combustion gas using a water pipe to generate hot water, and a hot water apparatus equipped with the heat exchanger. In the present invention, the water supplied into the water pipe is not limited to normal water such as tap water, but is a concept including, for example, an antifreeze liquid used for hot water heating and the like and a liquid similar thereto.

  As an example of the heat exchanger, the applicant of the present invention contains a plurality of linear tubular water pipes in a substantially rectangular parallelepiped case, and a combustion gas supply port and an exhaust port are provided at the front and rear of the case. A multi-tube type formed on the wall has been proposed previously (see, for example, Patent Document 1). In this heat exchanger, the heat exchange is performed when the combustion gas flowing into the case passes through the gaps between the plurality of water pipes, but the number of the plurality of water pipes is increased to increase the overall heat transfer area. As a result, the heat recovery amount can be increased. Moreover, since combustion gas advances toward the exhaust port from the air supply opening provided in the wall part before and behind the case, the whole lower part of a some water pipe can also be covered with the bottom wall part of a case. When recovering latent heat from combustion gas, water vapor in the combustion gas is condensed and a large amount of drain is generated, which causes a phenomenon of flowing down below the water pipe. According to the heat exchanger, such a drain is generated. Can be properly received by the bottom wall of the case. For this reason, the heat exchanger is suitable for latent heat recovery applications.

  However, the prior art has problems to be improved as described below.

  That is, in order to increase the heat exchange efficiency of the heat exchanger, the number of water pipes must be increased. However, when the number of water pipes is increased in this way, the total number of parts is increased, the structure becomes complicated, and the manufacturing work becomes troublesome. In particular, when attaching a water flow header to a large number of water pipes, the work of joining the individual ends of the large number of water pipes to the header is more troublesome. As a result, the manufacturing cost is expensive, and there is room for improvement in this respect.

  In addition, as a conventional heat exchanger, there is one using a so-called spiral water pipe as described in Patent Documents 2 to 4, for example, unlike the multi-tube type as described above. In this type of heat exchanger, since the water pipe is formed in a spiral shape, the heat transfer area of one water pipe can be increased. In view of this, the present inventor has conceived that in the structure of the heat exchanger as described above, the number of water pipes is reduced and the structure is simplified by replacing the water pipes with spiral water pipes. However, the spiral water tube has a unique shape in which a plurality of spiral loop portions connected in series are stacked. Accordingly, simply replacing such a spiral water pipe with the water pipe of the conventional multi-tube heat exchanger cannot efficiently cause the combustion gas to act on the entire spiral water pipe, resulting in high heat exchange efficiency. Hard to get.

Japanese Patent Laid-Open No. 2005-274043 Japanese Patent Laid-Open No. 62-288446 No. 6-8442 Japanese Patent No. 2835286

The present invention has been conceived under such circumstances, and has a simple structure that can reduce the manufacturing cost, achieve high heat exchange efficiency, and recover latent heat from combustion gas. It is an object of the present invention to provide a heat exchanger that can be suitably used for applications 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 1st side of the present invention is a heat exchanger provided with the case where the supply mouth and exhaust port of the heating gas are formed, and at least one water pipe. The water pipe includes a spiral tubular body portion in which a plurality of loop portions connected in series are stacked in the case through a plurality of gaps in the vertical height direction and a space portion is formed inward. And the air supply port and the exhaust port of the case are provided in an arrangement that sandwiches the intermediate portion in the width direction of the spiral tube body in the front-rear direction intersecting the width direction, and the spiral shape At least a part of the heating gas supplied into the case from the air supply port and proceeding to the space portion is provided at both ends in the width direction of the helical tube portion in the space portion inside the tube portion. It is characterized by a baffle that advances toward the part. There.

  According to such a configuration, the following effects can be obtained.

  1stly, the width direction intermediate part of the helical tube part of a water pipe will be divided into the area close | similar to the air supply opening which pinches | interposes a baffle, and the area | region close | similar to an exhaust opening. When entering, the heating gas first passes through the region near the air supply port in the intermediate portion in the width direction of the spiral tube portion, and reaches the inner space of the spiral tube portion. Then, at least a part of the heating gas collides with the baffle and its traveling direction is changed, and thereafter, it moves around both sides of the baffle while acting on both ends of the spiral tubular body in the width direction. Next, the combustion gas travels through the region near the exhaust port in the intermediate portion in the width direction of the spiral tube body, and is then discharged from the exhaust port to the outside of the case. As described above, according to the present invention, the heating gas can be applied uniformly to the entire spiral tube portion of the water tube. Therefore, high heat exchange efficiency can be obtained.

  Second, the water pipe is a so-called spiral water pipe, and the heat transfer area of one water pipe is large. Therefore, it is possible to obtain high heat exchange efficiency without increasing the number of water pipes, and the overall structure can be simplified by reducing the number of water pipes, and the manufacturing cost can be reduced. In addition, since the baffle is arranged in the inner space part originally formed by the helical tube part, there is no need to newly secure an extra space for attaching the baffle in the case, Its structure is reasonable.

  Third, it is possible to cover the entire lower part of the spiral tube part with a part of the case so that the drain can be properly received by the case when the drain flows down from the spiral tube part. It is. Therefore, the heat exchanger according to the present invention can be suitably used for a latent heat recovery application that involves generation of a large amount of drain.

  In a preferred embodiment of the present invention, the baffle has at least one ventilation opening at its widthwise intermediate portion, or has a non-uniform width dimension, whereby the air supply A part of the heating gas that has traveled from the mouth toward the baffle passes through the side of the ventilation opening or the narrow part of the baffle.

  According to such a configuration, a part of the heating gas that has progressed from the air supply port to the inner space of the spiral tubular body part remains on the side of the ventilation opening or the narrow part of the baffle. It passes through and proceeds to the region near the exhaust port in the intermediate portion in the width direction of the spiral tube portion or in the vicinity thereof. Therefore, it is appropriately avoided that these regions are shaded by the baffle and are less in contact with the heating gas than other regions. As a result, it becomes possible to cause the heating gas to act substantially uniformly on each part of the spiral tubular body portion, and it is more preferable to increase the heat exchange efficiency.

  In a preferred embodiment of the present invention, a plurality of water tubes each having the helical tube portion are provided, and the loop portions of the helical tube portions of the plurality of water tubes are spaced apart in the front-rear direction. And a pair of second tubular bodies connecting the both ends of the straight tubular pair extending in the width direction, and the plurality of helical tubular bodies include: The loop portions have different sizes, and are arranged in a substantially concentric wrapping shape.

  According to such a configuration, since the spiral tubular body portions of the plurality of water tubes are substantially concentrically wound, they are arranged in a space-efficient manner, and heat transfer is suppressed while suppressing an increase in overall size. The area can be increased. Further, each loop portion of the plurality of spiral tubular body portions has a pair of straight tubular first tube portions extending in the width direction at intervals in the front-rear direction. About the arrangement | sequence of a 1st pipe body part, it can be set as the arrangement | sequence similar to the water pipe of the conventional multitubular heat exchanger, and it aims at the increase in heat recovery amount, making the whole bulk small. It becomes more suitable.

  The hot water apparatus provided by the second aspect of the present invention introduces the heat exchanger provided by the first aspect of the present invention and the combustion gas as the heating gas into the case of the heat exchanger. And a combustor.

  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.

  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.

  FIGS. 1-6 has shown an example of the hot water supply apparatus as a specific example of the hot water apparatus with which this invention was applied, and a structure relevant to this. 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 gas burner, and is arranged in the can 30 and is configured such that fuel gas is supplied from the outside through a pipe 32. In the can 30, combustion air is blown upward from a blower fan 31 below. The primary heat exchanger 1 is for recovering sensible heat from the combustion gas generated and raised by the combustor 3, and has a structure in which a water pipe 11 having a plurality of fins 12 is arranged in a can body 10. have.

  The secondary heat exchanger B is for recovering latent heat from the combustion gas, and is disposed above the primary heat exchanger 1 and connected to the can body 10 via the auxiliary can body 19. ing. The secondary heat exchanger B includes a case 7 into which combustion gas is introduced, a plurality of (for example, a total of five) water pipes P, a baffle 8, and headers 6A and 6B for incoming and outgoing hot water. Each of the plurality of water pipes P has a spiral tubular body portion 5, and the plurality of spiral tubular body portions 5 are substantially concentrically wound as shown in FIG. 5. In the case 7.

  FIG. 6 shows one of the plurality of water pipes P. The water pipe P is manufactured by, for example, winding a metal pipe body, which is a raw material, and is connected in a spiral shape and arranged in a vertical height direction via a plurality of gaps 59. Loop portion 50 and extending tube portions 51 and 52 connected to the lower and upper portions thereof. Each loop portion 50 has a substantially oval shape in plan view, and has a semicircular arc shape in plan view that connects a pair of straight tubular body portions 50a and 50b extending in the width direction with a space in the front-rear direction and the ends thereof. A pair of tube portions 50c and 50d. In the present embodiment, the pair of tube portions 50a and 50b are described as the width direction intermediate portion S1, and the pair of tube portions 50c and 50d are described as the width direction both ends S2a and S2b. Specific contents of the intermediate portion and the both end portions are not limited to this.

  A pair of straight pipe parts 50a and 50b of each loop part 50 is a horizontal pipe part having no inclination with respect to a horizontal plane. On the other hand, the pair of tube portions 50c and 50d are inclined tube portions inclined with respect to the horizontal plane. More specifically, in FIG. 6 (a), the tube portion 50c gradually decreases in height as it proceeds in the arrow N1 direction from one end of the tube portion 50a toward one end of the tube portion 50b. It is inclined at an appropriate angle. The tube part 50a is higher than the tube part 50b. The tubular body portion 50d is inclined so that the height is gradually lowered as it proceeds in the arrow N2 direction from the other end of the tubular body portion 50b toward the other end of the tubular body portion 50a of the next-stage loop portion 50. Yes. Each of the plurality of loop portions 50 is configured to include the tube portions 50a to 50d configured as described above. The plurality of water pipes P are all configured as shown in FIG. However, as clearly shown in FIG. 5, the sizes of the loop portions 50 of the plurality of spiral tube portions 5 are different, and as described above, the plurality of spiral tube portions 5 are overlapped. They are arranged in a roll.

  The case 7 has a hollow, substantially rectangular parallelepiped shape, and includes an upper wall portion 70c and a bottom wall portion 70d that sandwich the plurality of helical tube portions 5 in the vertical height direction (vertical direction), and the plurality of helical tube portions 5. Has a rear wall portion 70a and a front wall portion 70b that sandwich the frame in the horizontal front-rear direction. The bottom wall portion 70d is provided with a drain outlet 73, and when the drain generated along with the latent heat recovery flows down from the plurality of spiral tube portions 5 onto the bottom wall portion 70d, The drain is discharged from the discharge port 73 to the outside of the case 7. The drain is generally strongly acidic containing nitrogen oxides in the combustion gas, and the parts that may come into contact with the drain, such as each part of the case 7 and the water pipe P, are made of stainless steel or other acid resistant materials. It is considered as an excellent material.

  The rear wall portion 70a and the front wall portion 70b of the case 7 are provided with an intake port 71 and an exhaust port 72 for combustion gas. The exhaust port 72 has a substantially rectangular shape as shown in FIG. 2, for example, and the air supply port 71 has a similar shape. As shown in FIG. 5, the air supply port 71 and the exhaust port 72 face the intermediate portion S1 in the width direction of the plurality of spiral tubular body portions 5 and are arranged so as to sandwich the intermediate portion S1 in the front-rear direction. ing. The combustion gas that has passed through the primary heat exchanger 1 and has traveled upward passes through the auxiliary can 19 and enters the case 7 through the air supply port 71 (see FIG. 3).

  The baffle 8 is in the form of a plate made of a metal such as stainless steel or other relatively hard material, and is arranged in the inner space 58 of the plurality of spiral tubular bodies 5. The space 58 has an elongated shape in which the dimension in the front-rear direction is considerably smaller than the dimension in the width direction, and such a configuration allows the pipe parts 50a and 50b to be close to each other so that the arrangement density of the pipe parts is reduced. To help increase. 5 (a) and 5 (c), the baffle 8 has a width approximately equal to the length of the tube portions 50a and 50b and the overall height of the plurality of spiral tube portions 5. Although having substantially the same height, an opening 80 for ventilation is formed near the center in the width direction. The opening 80 has, for example, a rectangular shape as viewed from the front and has a height dimension that is substantially close to the overall height of the plurality of spiral tubular body parts 5 and has a width of, for example, about 1/3 of the tubular body parts 50a and 50b. is there. However, as will be described later, the specific shape of the baffle 8 is not limited. The baffle 8 is attached by the upper end of the baffle 8 being joined to the upper wall portion 70c of the case 7, for example.

  As clearly shown in FIGS. 5A, 5 </ b> B, and 4, one end of each of the extending pipe portions 51 and 52 of the plurality of water pipes P penetrates the side wall 70 e of the case 7. It is pulled out of the case 7, and headers 6A and 6B for water entry and hot water are connected to that portion. Further, as shown in FIG. 1, a water inlet pipe 90 for supplying tap water or the like is connected to the opening 60A of the water inlet header 6A. The opening 60B of the header 6B for hot water is connected to the water inlet 11a of the primary heat exchanger 1 via a pipe 91. The primary heat exchanger 1 is configured such that the hot water sent from the secondary heat exchanger B passes through the water pipe 11 and is further heated, and the hot water generated in this way Hot water is discharged from 11b.

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

  In FIG. 1, the hot water supply apparatus A is combusted when water supplied from the inlet pipe 90 to the header 6A flows through the plurality of water pipes P of the secondary heat exchanger B and the water pipe 11 of the primary heat exchanger 1. The device 3 starts driving. Then, sensible heat and latent heat are sequentially recovered by the primary heat exchanger 1 and the secondary heat exchanger B from the combustion gas generated by the combustor 3. The water flowing through the plurality of water pipes P and the water pipe 11 is heated by such heat recovery, and the hot water generated by this heating is supplied from the hot water outlet 11b to a desired hot water supply destination.

  In the secondary heat exchanger B, first, when combustion gas flows into the case 7 from the air supply port 71, the combustion gas flows into a plurality of pipes in the intermediate portion S <b> 1 in the width direction of the plurality of spiral tubular body parts 5. It progresses to the area | region in which the body part 50a is provided. The plurality of tube portions 50a are arranged vertically and horizontally through a plurality of gaps, and heat recovery is performed when the combustion gas passes through the plurality of gaps. Next, when the combustion gas travels to the inner space 58 of the plurality of spiral tubular body parts 5, a part of the combustion gas collides with the baffle 8, and as shown by an arrow N3 in FIG. It progresses toward both ends S2a and S2b in the width direction of the spiral tubular body portion 5. For this reason, heat recovery is also appropriately performed by the plurality of tube portions 50c and 50d. Thereafter, the combustion gas passes through both sides of the baffle 8 as shown by an arrow N4, and circulates in a region closer to the exhaust port 72 than the baffle 8. For this reason, the combustion gas also travels to a region where the plurality of tube portions 50b are provided, and heat is also recovered in this region, and is then discharged from the exhaust port 72 to the outside of the case 7.

  On the other hand, some combustion gases pass directly through the ventilation opening 80 of the baffle 8 as indicated by an arrow N5. This combustion gas is discharged from the exhaust port 72 to the outside of the case 7 after passing through the region where the plurality of tube parts 50b are provided. Unlike the present embodiment, when only a plurality of combustion gases travel along the paths of the arrows N3 and N4 described above, when the plurality of tube portions 50b have a relatively long dimension, their vicinity in the center in the longitudinal direction It may be difficult to let a large amount of combustion gas act on the surface. On the other hand, in this embodiment, by providing the baffle 8 with the opening 80 for ventilation, it is possible to actively advance a large amount of combustion gas in such a portion. The fear is solved appropriately.

  As understood from the above description, in the secondary heat exchanger B, it is possible to cause the combustion gas to appropriately act on the entire loop portions 50 of the plurality of helical tube portions 5. In addition, it is possible to make the flow rate of the combustion gas uniform in each place. Therefore, heat recovery that efficiently utilizes the entirety of the plurality of spiral tubular body parts 5 is performed, and high heat exchange efficiency is obtained.

  Further, in this secondary heat exchanger B, since the water pipe P having the helical tube body part 5 is used, as a means for increasing the entire heat transfer area of the water pipe P, the total number of them is set. There is no need to do so much. Therefore, it is possible to reduce the number of parts, facilitate the manufacturing operation, and reduce the manufacturing cost. In particular, when the number of water pipes P is small, the operation of connecting the headers 6A and 6B to a plurality of water pipes P is facilitated. Moreover, although a part of each water pipe P is made into the structure penetrated to the side wall 70e of the case 7, the formation work of such a structure becomes easy.

  The entire lower region of the plurality of helical tube parts 5 is covered by the bottom wall part 70d of the case 7, and as described above, the drain generated by the latent heat recovery is appropriately received by the bottom wall part 70d, It is discharged from the discharge port 73 to the outside of the case 7. Therefore, contamination of other parts of the hot water supply apparatus A by the drain is also appropriately prevented.

  As described with reference to FIG. 6, in each loop part 50 of the water pipe P, only the pipe parts 50c and 50d are inclined with respect to the horizontal plane, and the pipe parts 50a and 50b are horizontal. For this reason, unlike this embodiment, for example, when compared with the case where all the portions of the loop portion 50 are inclined with respect to the horizontal plane, the width of the loop portion 50 in the vertical direction is reduced. The winding pitch p2 (the arrangement pitch of the loop portions 50) can also be reduced. As a result, even when the number of stages of the loop portion 50 is increased to increase the amount of heat recovery, the overall height dimension of the spiral tubular body portion 5 is not so increased, and the overall size is appropriately suppressed. It is possible. In particular, in the present embodiment, the loop portion 50 has a substantially oval shape in plan view, and by increasing the length of the tube portions 50a and 50b, the spiral tube portion 5 is not increased in height. The heat transfer area of the tubular body 5 can be increased.

  The present invention is not limited to the embodiment described above. 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.

  Although it is preferable that the baffle is provided with an opening for ventilation in the intermediate portion in the width direction, the baffle may be configured not to provide such an opening. On the other hand, when providing the opening part for ventilation | gas_flowing, it can also be set as the structure different from the said embodiment. FIG. 7 shows such a specific example. In FIG. 2A, the opening 80 of the baffle 8 is formed in a narrow width. In FIG. 2B, a plurality of narrow openings 80 are provided. In FIG. 3C, the opening 80 is formed as a non-notched hole. In FIG. 4D, each of the plurality of openings 80 is formed in a small hole shape, and the positions where the plurality of openings 80 are formed are porous, such as punching metal. As described above, the specific shape, size, number, position, and the like of the baffle ventilation opening can be selected variously. By appropriately selecting these, the combustion gas passing through the baffle 8 as it is can be selected. The ratio with the combustion gas that is not so can be set to a more suitable condition for improving the heat exchange efficiency.

  Further, as shown in FIG. 8, the baffle 8 may be formed into a shape having a non-uniform width dimension, for example, by forming it in a trapezoidal shape. In the configuration shown in the figure, the lower side of the baffle 8 is narrower than the upper side, and the upper side of both ends in the width direction of the baffle 8 blocks the combustion gas that has progressed. On the other hand, the lower side of the baffle 8 is narrow, and the regions on both sides (regions indicated by reference numeral n1) are regions through which the combustion gas passes. Therefore, even if the width of the baffle 8 is made non-uniform and the shape and size thereof are variously selected, the flow rate ratio between the combustion gas passing through the baffle 8 as it is and the combustion gas that is not so is more suitable for improving the heat exchange efficiency. It is possible to set a condition. In addition, the baffle 8 shown in FIG. 8 can be used upside down. Furthermore, a configuration in which the width of the baffle 8 is not uniform as shown in FIG. 8 may be combined with a configuration in which an opening 80 for ventilation is provided in the intermediate portion in the width direction as shown in FIG.

  The baffle 8 is not limited to a flat plate shape, and for example, as shown in FIG. 9, the baffle 8 may have a configuration in which bent portions 81 are provided at both ends in the width direction. Further, the baffle 8 may not be plate-shaped, and may be configured by combining a plurality of members. In the case of forming a baffle having an opening for ventilation in the intermediate portion in the width direction, for example, two plate members may be arranged at intervals, and the gap portion may be configured as an opening for ventilation.

  In the present invention, a water tube having a helical tube portion is used, but the shape of each loop portion of the helical tube portion is not limited to a substantially oval shape in plan view, but is substantially rectangular in plan view. It can also be formed in other shapes such as a shape or a substantially circular shape. The loop part may have substantially the same dimension in the width direction and the dimension in the front-rear direction. Further, although not realistic, in the present invention, the number of water pipes can be one. Although it is preferable that each loop part of the spiral tube part is configured such that the intermediate part in the width direction is horizontal and the both end parts in the width direction are inclined, it is not limited to this. The entire loop portion may be inclined.

  The case is not limited as long as the case accommodates the helical tube portion of the water tube and into which a heating gas such as combustion gas can flow into the case. The heating gas supply port and the exhaust port may be provided so as to sandwich the intermediate portion in the width direction of the helical tube body in the front-rear direction, and the size thereof is not limited.

  In the embodiment described above, the present invention is not applied to the primary heat exchanger for sensible heat recovery, but the heat exchanger according to the present invention may be of any type for sensible heat recovery and latent heat recovery. . The heat exchanger according to the present invention can also be used for sensible heat recovery.

  In the hot water apparatus according to the present invention, a combustor other than a gas burner may be used, and for example, an oil burner may be used. 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. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a left view of the secondary heat exchanger of the hot-water supply apparatus shown in FIG. (a) is a plane sectional view of the secondary heat exchanger of the hot water supply apparatus shown in FIG. 1, (b) is a front sectional view thereof, and (c) is a sectional view taken along line VV of (a). It is. (a) is a top view which shows an example of the water pipe of the secondary heat exchanger shown in FIG. 5, (b) is VI-VI sectional drawing of (a). (a)-(d) is a front view which shows the other example of the baffle used in this invention. It is a front view which shows the other example of the baffle used in this invention. (A) is a top view which shows the other example of the baffle used in this invention, (b) is the front view.

Explanation of symbols

A Hot water supply device (hot water device)
B Secondary heat exchanger (heat exchanger)
P water pipe S1 width direction middle part (of spiral tube part)
S2a, S2b Width direction both ends (spiral tube part)
3 Combustor 5 Spiral tube section 6A, 6B Header 7 Case 8 Baffle 50 Loop section (of spiral tube section)
58 Space (inside the spiral tube)
71 Air supply port 72 Air exhaust port 80 Ventilation opening

Claims (4)

A heat exchanger comprising a case in which a supply port and an exhaust port for a heating gas are formed, and at least one water pipe,
The water pipe has a spiral tubular body part in which a plurality of loop parts connected in series are stacked in the case with a plurality of gaps in the vertical height direction and a space part is formed inward. And
The air supply port and the exhaust port of the case are provided in an arrangement that sandwiches the intermediate portion in the width direction of the helical tube portion in the front-rear direction intersecting the width direction,
In the space inside the helical tube portion, at least a part of the heating gas supplied into the case from the air supply port and proceeding to the space portion is transferred to the spiral tube portion. A heat exchanger characterized in that a baffle is provided that advances toward both ends in the width direction.   The baffle has progressed from the air supply port toward the baffle by having at least one ventilation opening at the intermediate portion in the width direction or having a non-uniform width dimension. 2. The heat exchanger according to claim 1, wherein a part of the heating gas is configured to pass directly through a side of the ventilation opening or a portion where the width of the baffle is narrow. A plurality of water pipes each having the spiral tubular body part;
Each loop portion of the spiral tubular body portions of the plurality of water tubes has a pair of straight tubular first tube portions extending in the width direction at intervals in the front-rear direction and a pair of first tube portions that connect the both end portions. Two tube parts,
3. The heat exchanger according to claim 1, wherein the plurality of spiral tubular body portions are arranged in a substantially concentric overlapping shape with different sizes of the loop portions.   Hot water comprising: the heat exchanger according to any one of claims 1 to 3; and a combustor that introduces combustion gas as the heating gas into a case of the heat exchanger. apparatus.

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