JP2018119757A - Heat exchanger and water heater including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger that properly prevents or suppresses occurrence of unreasonable stress in each part when a heat transfer pipe is deformed due to water pressure in the heat transfer pipe and has excellent durability.SOLUTION: A heat exchanger HE includes a stepped press part 30 positioned in a mutual region of both end parts 2a, 2b in a longitudinal direction of a plurality of heat transfer pipes 2 of a side plate part 3A on one end side in a lateral width direction of a case C and formed integrally with the side plate part 3A so that a projection part is formed in one of an inner surface side and an outer surface side of the side plate part 3A and a recess part 30a is formed in the other.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a heat exchanger for recovering heat from a heating gas such as a combustion gas generated by a burner, and a hot water supply apparatus including the heat exchanger.

Specific examples of the heat exchanger for the hot water supply apparatus include those described in Patent Documents 1 and 2.
In the heat exchangers described in these documents, a plurality of meandering heat transfer tubes are accommodated in a case, and combustion gas generated by a burner is supplied into the case. Each longitudinal end portion of each of the plurality of heat transfer tubes is fixedly connected to a side plate portion on one end side in the lateral width direction of the case or a header portion provided on the side plate portion.
According to such a configuration, it is possible to appropriately heat the hot water flowing through the plurality of heat transfer tubes by the combustion gas supplied into the case.

  However, the prior art still has room for improvement as described below.

  That is, as schematically shown in FIG. 8, when hot water is supplied into the meandering heat transfer tube 2 and the internal pressure of the heat transfer tube 2 becomes high, the heat transfer tube 2 is connected to the heat transfer tube 2 as indicated by an arrow Na. Deformation (widening deformation) in the direction in which the overall width widens. On the other hand, since both longitudinal ends 2a and 2b of the heat transfer tube 2 are connected to the side plate portion 3A of the case in a state of being spaced apart from each other, the above-described widening deformation of the heat transfer tube 2 is caused by the arrow Nb of the side plate portion 3A. It is accompanied by bending deformation in the direction indicated by. As a result, a large stress is generated at the connection portion between the heat transfer tube 2 and the header portion (not shown) in addition to the connection portion between the longitudinal ends 2a and 2b of the heat transfer tube 2 and the side plate portion 3A. Such stress can cause cracks and the like, and thus is not preferable for enhancing the durability of the heat exchanger.

Japanese Patent No. 4148803 Japanese Patent No. 4574535

  The present invention has been conceived under the circumstances as described above, and appropriately prevents unreasonable stress from being generated in each part due to deformation of the heat transfer tube due to the water pressure in the heat transfer tube. Alternatively, it is an object of the present invention to provide a heat exchanger that can be suppressed and have excellent durability and the like, and a hot water supply 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 includes a case in which a heating gas is supplied and a side plate portion is provided at one end in the width direction, and is accommodated in the case. A heat exchanger comprising: a plurality of heat transfer tubes connected to the side plate portion or a member joined to the side plate portion so that both longitudinal end portions thereof are separated in the front-rear direction or the vertical height direction And among the said side plate parts, it is located in the mutual area | region of the longitudinal direction both ends of these heat exchanger tubes, and one side of the outer surface side of the said side plate part and an inner surface side becomes a convex part, and the other becomes a recessed part. As described above, a step pressing portion integrally formed with the side plate portion is further provided.
Here, the horizontal width direction, the front-rear direction, and the vertical height direction are directions in the heat exchanger. For example, in a state in which the heat exchanger is incorporated in the hot water supply device, the direction in the hot water supply device does not necessarily match. Absent.

According to such a configuration, the following effects can be obtained.
That is, among the side plates of the case, the stepped portion integrally formed in the area between the longitudinal ends of the plurality of heat transfer tubes enhances the rigidity of the side plates, and in particular the ends of the heat transfer tubes in the longitudinal direction. In the front-rear direction or the vertical height direction in which they are separated from each other, the side plate portion exerts an action of suppressing a large deformation. For this reason, even if hot water is supplied to each heat transfer tube and the internal pressure of each heat transfer tube is increased, the side plate portion of the case is greatly deformed accordingly even if each heat transfer tube is about to undergo widening deformation. It does not do, and it suppresses the widening deformation of each heat exchanger tube. As a result, in addition to being able to reduce the amount of widening deformation of each heat transfer tube, a large stress is not generated at the connection point between the longitudinal end portions of each heat transfer tube and the side plate portion or the connection portion with the header portion or the like. Can be. Therefore, it is possible to eliminate the problem that cracks or the like are easily generated in various portions of the heat exchanger due to the widening deformation of the heat transfer tube, and it is possible to improve the durability performance of the heat exchanger.
In addition, the stepped portion can be easily formed by, for example, pressing the side plate portion, and does not increase the number of parts and weight, and the manufacturing cost can be suppressed at a low cost. .

In the present invention, preferably, each of the plurality of heat transfer tubes includes a plurality of straight tube portions extending in the lateral width direction with a space in the front-rear or vertical direction, and ends of the plurality of straight tube portions. A plurality of folded tube body portions that connect the portions, and the stepped pressing portion is formed such that the inner surface side of the side plate portion is a concave portion, and the concave portion includes the plurality of the plurality of folded tube body portions. At least a part of the folded tube portion has entered.
Here, as a specific example of the plurality of heat transfer tubes, for example, a meandering heat transfer tube as described in Patent Documents 1 and 2, or a plan view as described in Japanese Patent Application Laid-Open No. 2014-70844. A spiral heat transfer tube such as a substantially oval, a substantially oval, or a substantially rectangular shape can be used.

According to such a configuration, the following effects can be obtained.
That is, the width of the gap (gap in the recess) formed between the heat transfer tube and the side plate portion is reduced by a part of the heat transfer tube entering the recess of the stepped portion provided in the side plate portion. Is possible. When the width of the gap is large, a large amount of heating gas flows into the gap, and the heat of the heating gas is radiated to the outside of the case through the side plate portion, or the heating gas acts on the heat transfer tube. Without causing a phenomenon such as reaching the exhaust port of the case, and the heat exchange efficiency decreases. On the other hand, according to the said structure, it is possible to eliminate such a fear and to improve heat exchange efficiency.
Further, it is possible to increase the length of the heat transfer tube by the dimension in which the folded tube portion enters the recess of the stepped portion. As a result, it is possible to increase the total heat transfer area of the entire plurality of heat transfer tubes and improve the heat recovery capability while suppressing an increase in the size of the entire case.

  In the present invention, preferably, among the plurality of folded tube portions, all the folded tube portions located on the side facing and approaching the inner surface of the side plate portion enter the recessed portion.

  According to such a configuration, the heating gas can be made more difficult to flow into the recess of the stepped portion, and the heat of the heating gas can be prevented from being radiated to the outside of the case through the side plate portion, and the recess A large amount of heat can be recovered from the heating gas that has flowed into the container using the folded tube portion. Therefore, it is more preferable in increasing the heat exchange efficiency. Further, it is possible to further increase the length of the heat transfer tube and improve the heat recovery capability.

In the present invention, preferably, the case includes a side plate portion on the other end side located at the other end portion in the lateral width direction, and the side plate portion on the other end side is provided with an additional step press whose inner surface side is a concave portion. And at least a part of the folded tube body that is opposed to and close to the inner surface of the side plate portion on the other end side of the plurality of folded tube body portions. Department has entered.

  According to such a configuration, the rigidity of the side plate portion on the other end side of the case can be increased, and the strength of the entire case can be improved. In addition, a large amount of heating gas flows between the additional stepped portion and the side plate portion on the other end side, and the heat of the heating gas is transferred to the outside via the side plate portion on the other end side. It is possible to reduce the loss of heat dissipation.

  In the present invention, preferably, it is provided on the outer surface portion or the outer side of the side plate portion, and includes a pair of header portions for allowing the plurality of heat transfer tubes to flow hot water, Among the side plate portions, at least a part of an inter-region between the pair of header portions is formed so as to protrude outward of the side plate portion, and in the lateral width direction, the step pressing portion and the pair of pair The header part overlaps each other.

  According to such a configuration, in the lateral width direction of the case, the pair of header portions can be prevented from protruding in a larger dimension outward than the stepped portion of the side plate portion of the case. Therefore, it is preferable when suppressing the enlargement of the whole heat exchanger.

  The hot water supply apparatus provided by the second aspect of the present invention is a hot water supply apparatus provided with a heat exchanger for heating hot water by performing heat recovery from a heating gas, as the heat exchanger. The heat exchanger provided by the first aspect of the present invention is used.

  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.

It is a perspective view which shows an example of the heat exchanger which concerns on this invention. It is a principal part disassembled perspective view of the heat exchanger shown in FIG. FIG. 2 is a plan sectional view of FIG. 1. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. It is a schematic sectional drawing which shows an example of the hot water supply apparatus provided with the heat exchanger shown in FIG. 1, and the heat exchanger HE shown by this figure is equivalent to the VI-VI cross section of FIG. It is a plane sectional view showing a schematic structure of other examples of the present invention. It is principal part explanatory drawing which shows an example of an effect | action of a prior art schematically.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
For ease of understanding, the same reference numerals as those in FIG. 8 are used for elements that are the same as or similar to those in the configuration shown in FIG.

  The heat exchanger HE shown in FIGS. 1 to 5 includes a case C, a plurality of heat transfer tubes 2 accommodated in the case C, and a pair of header portions H (Ha, Hb) for incoming and outgoing hot water. Yes.

The case C has a substantially rectangular parallelepiped shape as a whole, and includes a substantially rectangular tube-shaped case main body 1 having both ends opened in the lateral width direction, and a pair of side plate portions 3A and 3B that close both end opening portions of the case main body 1. Yes. The side plate portion 3B corresponds to an example of the “side plate portion on the other end side” in the present invention. Each of the case main body 1 and the pair of side plate portions 3A, 3B is formed by, for example, pressing or bending a stainless steel plate, and the pair of side plate portions 3A, 3B are formed at both ends of the case main body 1. After being fitted into the opening, it is joined to the case body 1 by means such as brazing. The rear wall 10a and the front wall 10b of the case body 1 are provided with an air supply port 11 and an exhaust port 12 for allowing combustion gas as a heating gas to flow into and out of the case C.
The side plate portions 3A and 3B are provided with a step pressing portion 30 and an additional step pressing portion 31, which will be described later.

  Each of the heat transfer tubes 2 has, for example, a meandering shape in plan view, extends in the lateral width direction of the case C, and has a plurality of straight tube portions 22 spaced in the front-rear direction of the case C, and the plurality of straight tubes. And a plurality of folded tube portions 23 that are integrally connected to the portion 22 and that connect the ends of the adjacent straight tube portions 22 to each other. The plurality of heat transfer tubes 2 are stacked in the vertical height direction. However, the heat transfer tubes 2 adjacent to each other in the vertical height direction are arranged so as to be displaced by an appropriate dimension in the front-rear direction of the case C.

  Both end portions 2a and 2b (longitudinal end portions) of each heat transfer tube 2 pass through the side plate portion 3A of the case C and are drawn from the case C to the outside of the side plate portion 3A. Are fitted with headers Ha and Hb for entering and discharging water. Since the two end portions 2a and 2b are separated from each other in the front-rear direction of the case C, the end portion 2a passes through the front region of the side plate portion 3A, and the end portion 2b is the rear region of the side plate portion 3A. It penetrates. Both end portions 2a and 2b are fixedly connected to the side plate portion 3A using, for example, brazing means.

  As shown in FIG. 2, each header portion H includes a header main body portion 4 and a header lid member 5. The header main body 4 has a substantially cup shape having a plurality of holes 42 through which the end portions 2a or the end portions 2b of the plurality of heat transfer tubes 2 are inserted. The header lid member 5 has a joint pipe 53 for connecting an external pipe in which an opening 52 for water entry or hot water is formed, and is fitted to the header body 4 and joined by means such as brazing. The A chamber 48 communicating with the inside of the end 2a or the end 2b of each heat transfer tube 2 is formed between the two (see FIG. 5). The end 2a or end 2b of each heat transfer tube 2 and the header main body 4 are also joined together by means such as brazing.

  In the side plate portion 3A, a stepped portion 30 is provided in a region between both end portions 2a, 2b of the plurality of heat transfer tubes 2. The stepped portion 30 is integrally formed with the side plate portion 3A so that the outer surface side of the side plate portion 3A becomes a convex portion and the inner surface side becomes a concave portion 30a, and can be formed by pressing the side plate portion 3A. The stepped portion 30 has, for example, a substantially rectangular shape in the front view of the side plate portion 3A, and is preferably formed in a relatively large size so as to avoid interference with the pair of header portions H. Basically, the rigidity of the side plate portion 3A can be further increased as the size of the stepped portion 30 is increased.

  The step pushing portion 30 is provided so as to correspond to the plurality of folded tube body portions 23 of the plurality of heat transfer tubes 2, and the recessed portion 30 a of the step pushing portion 30 includes the plurality of folded tube body portions 23. At least a portion is configured to enter. Preferably, as shown in FIG. 3 and FIG. 4, among the plurality of folded tube portions 23, all the folded tube portions 23 located on the side facing and approaching the inner surface of the side plate portion 3 </ b> A are in the recess 30 a. It is set to enter.

As shown in FIG. 3, in the lateral width direction of the case C, the stepped portion 30 and the pair of header portions H are provided so as to overlap each other with appropriate dimensions. This configuration can bring about an effect of reducing the size in which each header portion H protrudes outward in the lateral width direction from the outer surface portion of the stepped portion 30.

  The side plate portion 3B of the case C is provided with an additional step pressing portion 31. This additional stepped portion 31 is formed so that the inner surface side of the side plate portion 3B becomes a concave portion 31a, and the side plate portion 3B of the folded tube body portions 23 of the plurality of heat transfer tubes 2 is formed in the concave portion 31a. At least a part of the folded tube portion 23 that is opposed to and approaches the inner surface of the inner wall of the inner wall of the inner wall of the inner wall of the inner wall of the inner wall of the inner wall of the inner wall of the inner wall of FIG. Preferably, all the folded tube parts 23 facing and approaching the inner surface of the side plate part 3B have entered the recess 31a.

FIG. 6 shows an example of a hot water supply device WH provided with the heat exchanger HE described above.
The hot water supply device WH is mounted on a burner 60 for generating combustion gas, a fan 61 for supplying combustion air, and a burner case 62, and a primary heat exchanger for recovering sensible heat from the combustion gas. 7 and the heat exchanger HE is used as a secondary heat exchanger for recovering latent heat. The primary heat exchanger 7 has a configuration in which a heat transfer tube 71 and a plurality of fins 72 attached thereto are accommodated in a can body 70. The combustion gas after the sensible heat recovery is supplied to the air supply port 11 of the heat exchanger HE via the auxiliary can body 79. Hot water to be heated is supplied to a header portion H (Ha) for entering water of the heat exchanger HE, heated through a plurality of heat transfer tubes 2, and then primary from the header portion H (Hb) for tapping hot water. It is supplied to the heat transfer tube 71 of the heat exchanger 7 and further heated, and then supplied to a predetermined hot water supply destination.

  Next, the operation of the heat exchanger HE and the hot water supply device WH provided with the heat exchanger HE will be described.

  When water is introduced into the plurality of heat transfer tubes 2 and the internal pressure of these heat transfer tubes 2 is increased, the force for widening and deforming the plurality of heat transfer tubes 2 is the same as in the case of FIG. 8 described above. Can occur. However, in the present embodiment, the rigidity of the side plate portion 3A is increased by the formation of the stepped portion 30, and it is difficult for deformation to occur. Since the stepped portion 30 is formed at a substantially central portion of the side plate portion 3A and is formed in a relatively large size, the side plate portion 3A is more difficult to bend and deform. For this reason, unlike the structure shown in FIG. 8, the plurality of heat transfer tubes 2 are less likely to cause widening deformation accompanied by bending deformation of the side plate portion 3 </ b> A. When the plurality of heat transfer tubes 2 are greatly widened and deformed, stress is generated at a joint portion between the heat transfer tube 2 and the side plate portion 3A, a joint portion between the heat transfer tube 2 and the header portion H, and cracks are generated at these portions. However, according to this embodiment, it is possible to appropriately avoid such a concern and to improve the durability of the heat exchanger HE.

  The combustion gas that has flowed into the case C from the air supply port 11 reaches the exhaust port 12 after acting on the plurality of heat transfer tubes 2. In this process, a part of the combustion gas is recessed in the stepped portion 30. Flows into 30a. On the other hand, a part of the plurality of folded tube portions 23 has entered the recess 30a, and preferably all the folded tube portions 23 that face and approach the side plate portion 3A have entered. It is possible to prevent a gap having a large width from being formed between the folded tube portion 23 and the side plate portion 3A. It is possible to efficiently recover heat from the combustion gas that has flowed into the recess 30a by the plurality of folded tube portions 23.

  Further, according to the configuration in which the folded tube body portion 23 of the heat transfer tube 2 enters the recess 30a, the heat transfer tube 2 can be made longer than the configuration in which the folded tube body portion 23 does not enter the recess 30a. Therefore, the heat transfer area of the heat transfer tube 2 can be increased. For this reason, the heat exchanger HE can be made excellent in heat exchange efficiency.

As described above, since the additional step pressing portion 31 is provided in the other side plate portion 3B of the case C, the rigidity of the side plate portion 3B is also increased. Therefore, it is more preferable in increasing the overall mechanical strength of the case C. On the other hand, since the plurality of folded tube portions 23 also enter the recessed portions 31a of the additional stepped portion 31, the folded tube portion 23 has entered the recessed portions 30a of the stepped portion 30 described above. Similarly to the case, efficient heat recovery from the combustion gas can be performed also in the region near the side plate portion 3B, and excellent heat exchange efficiency can be obtained.

  FIG. 7 shows another embodiment of the present invention. In the figure, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment, and redundant description is omitted.

  In the embodiment shown in FIG. 7, an outwardly projecting stepped portion 32 for forming a header is integrally formed on the side plate portion 3 </ b> A of the case C, and each header portion H forms a header on the stepped portion 32. The member 5 </ b> A is configured by external fitting and joining. Both end portions 2a and 2b of each heat transfer tube 2 are penetrated and joined to the side plate portion 3A. A step pressing portion 30 is provided in a region between the pair of header portions H.

In the present embodiment, the side plate portion 3 </ b> A is formed with a pair of step pressing portions 32 for forming each header portion H. The step pressing portions 32 are both end portions 2 a and 2 b of the heat transfer tube 2. Is a stepped portion formed in a region to which the heat transfer tube 2 is connected, and is a part for simplifying the formation of the header portion H, and the stepped portion intended by the present invention for suppressing widening deformation of the heat transfer tube 2 Does not correspond to
As can be understood from the configuration shown in FIG. 7, the header portion referred to in the present invention can also be configured using the side plate portion of the case. A configuration in which the folded tube portion 23 of the heat transfer tube 2 is not allowed to enter the recessed portion 30a of the step pressing portion 30 may be adopted. Moreover, about the side-plate part 3B, it can also be set as the structure which does not form a step pushing part.

  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 supply apparatus according to the present invention can be modified in various ways within the intended scope of the present invention.

  In the present invention, the end portion of the heat transfer tube may not be directly connected to the side plate portion of the case. For example, when a member constituting the header portion is joined to the side plate portion, The ends of the heat transfer tubes may be connected (for example, Patent Documents 1 and 2 have the same configuration as this).

  The step pressing portion (step pressing portion 30) for suppressing the widening deformation of the heat transfer tube in the present invention can have a shape other than a substantially rectangular shape in front view. The size of the front view is preferably as large as possible, but is not limited to this, and may be a smaller size. Also, a plurality of step pressing portions can be provided. For example, a configuration is adopted in which elongated rectangular step pressing portions extending in the front-rear direction of the case are provided in a plurality of steps at appropriate intervals in the vertical height direction. It is also possible. The same applies to the additional step pressing portion.

  The heat transfer tube is not limited to a meandering shape, and other forms such as a spiral heat transfer tube can also be used. The plurality of heat transfer tubes are not limited to a structure in which the heat transfer tubes are stacked in the vertical height direction of the case, and may have a structure in which the heat transfer tubes are stacked in the front-rear direction of the case. In this case, it is customary that both end portions in the longitudinal direction of the heat transfer tubes are arranged apart from each other in the vertical height direction, and the stepped portion intended by the present invention is formed in the region between them. .

The present invention is not limited to the heat exchanger for recovering latent heat, and can be applied without questioning the type of sensible heat recovery or latent heat recovery. In addition, one case can accommodate a plurality of heat transfer tubes constituting a plurality of water channels in one case, not limited to one in which a heat transfer tube constituting one channel is accommodated (one can / one water channel type). It can also be configured as one (multi-channel type of one can such as one can and two water channels).
The heating gas is not limited to the combustion gas generated by the burner, but can be high-temperature exhaust gas discharged from, for example, a cogeneration system.

C Case HE Heat exchanger WH Water heater H (Ha, Hb) Header 1 Case body 2 Heat transfer tubes 2a, 2b End (of heat transfer tube)
22 Straight tube portion 23 Folded tube portion 3A Side plate (on one end side of the case)
3B side plate (on the other end of the case)
30 Step pushing portion 30a Concavity (of the step pushing portion)
31 Additional stepped portion 31a Recessed portion (of additional stepped portion)

Claims (6)

A case in which a heating gas is supplied inside, and a side plate portion is provided at one end in the width direction;
A plurality of heat transfer tubes accommodated in the case and connected to the side plate portion or a member joined to the side plate portion such that both ends in the longitudinal direction are separated in the front-rear direction or the vertical height direction;
A heat exchanger comprising:
Among the side plate portions, the side plates are located in a region between the longitudinal ends of the plurality of heat transfer tubes, and one of the outer surface side and the inner surface side of the side plate portion is a convex portion and the other is a concave portion. A heat exchanger, further comprising a step pressing portion integrally formed with the portion. The heat exchanger according to claim 1,
Each of the plurality of heat transfer tubes includes a plurality of straight tube portions extending in the lateral width direction at intervals in the front-rear direction or the vertical direction, and a plurality of folded portions that connect the ends of the plurality of straight tube portions. It has a configuration with a tube part,
The stepped pressing portion is a heat exchanger formed such that the inner surface side of the side plate portion becomes a concave portion, and at least a part of the plurality of folded tube body portions enter the concave portion. The heat exchanger according to claim 2,
Of the plurality of folded tube portions, all the folded tube portions positioned on the side facing and approaching the inner surface of the side plate portion have entered the recess. The heat exchanger according to claim 2 or 3,
The case includes a side plate on the other end located at the other end in the width direction,
The side plate portion on the other end side is formed with an additional stepped portion having a concave portion on the inner surface side, and in the concave portion of the additional stepped portion, the plurality of folded tube body portions, A heat exchanger in which at least a part of the folded tube body facing and approaching the inner surface of the side plate portion on the other end side enters. The heat exchanger according to any one of claims 1 to 4,
Provided with a pair of header portions provided on the outer surface portion or the outer side of the side plate portion, and for causing the plurality of heat transfer tubes to circulate hot water,
The step pressing portion is formed such that at least a part of an area between the pair of header portions of the side plate portions protrudes outward from the side plate portion, and in the lateral width direction, A heat exchanger, wherein the push portion and the pair of header portions overlap each other. A hot water supply apparatus comprising a heat exchanger for heating hot water by performing heat recovery from a heating gas,
A hot water supply apparatus, wherein the heat exchanger according to any one of claims 1 to 5 is used as the heat exchanger.

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