JP6858343B2 - Heat exchanger and water heater equipped with it - Google Patents

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 device including the heat exchanger.

Specific examples of the heat exchanger for the hot water supply device 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 housed in a case, and the combustion gas generated by the burner is supplied to the case. Both ends of each of the plurality of heat transfer tubes in the longitudinal direction are 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, in the above-mentioned prior art, there is still 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 becomes the heat transfer tube 2 as shown by an arrow Na. Deforms in the direction in which the overall width expands (widening deformation). On the other hand, since both ends 2a and 2b of the heat transfer tube 2 in the longitudinal direction are connected to the side plate portion 3A of the case at a distance from each other, the widening deformation of the heat transfer tube 2 described above 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 amount of stress is generated at the connecting portion between the heat transfer tube 2 and the header portion (not shown) in addition to the connecting portion between both end portions 2a and 2b in the longitudinal direction of the heat transfer tube 2 and the side plate portion 3A. Such stress can cause cracks and the like, and is not preferable for improving the durability of the heat exchanger.

Japanese Patent No. 4148803 Japanese Patent No. 4574535

The present invention has been conceived under the above-mentioned circumstances, and appropriately prevents undue 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 capable of suppressing the heat exchanger and making it excellent in durability and the like, and a hot water supply device equipped with the heat exchanger.

In order to solve the above problems, the following technical measures are taken in the present invention.

The heat exchanger provided by the first aspect of the present invention includes a case in which a heating gas is supplied to the inside and a side plate portion at one end in the width direction, and a case housed 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 ends in the longitudinal direction are separated from each other in the front-rear direction or the vertical height direction. In the region between both ends of the plurality of heat transfer tubes in the longitudinal direction of the side plate portions, a part of the side plate portion is larger than a general portion which is a non-step pushing portion of the side plate portion. A stepped push portion that partially protrudes to the outer side of the case, has a convex portion on the outer surface side, and has a concave portion on the inner surface side is integrally formed, and each of the plurality of heat transfer tubes is spaced in the front-rear direction or the vertical direction. It is configured to include a plurality of straight pipe portions that are arranged side by side with each other and extend in the lateral width direction, and a plurality of folded pipe portions that connect the ends of the plurality of straight pipe portions. At least a part of the plurality of folded pipe bodies is characterized in that it has entered the recess of the stepped push portion.
Here, the width direction, the front-rear direction, and the vertical height direction are directions in the heat exchanger, and are not necessarily the same as the directions in the hot water supply device when the heat exchanger is incorporated in the hot water supply device, for example. Absent.
Specific examples of the plurality of heat transfer tubes include a meandering heat transfer tube as described in Patent Documents 1 and 2, or a substantially elliptical plan view as described in Japanese Patent Application Laid-Open No. 2014-70844. Examples thereof include a spiral heat transfer tube having a substantially oval shape or a substantially rectangular shape.

According to such a configuration, the following effects can be obtained.
That is, among the side plate portions of the case, the stepped portion integrally formed in the region between the both ends in the longitudinal direction of the plurality of heat transfer tubes enhances the rigidity of the side plate portions, and in particular, both ends in the longitudinal direction of the heat transfer tubes are formed. It exerts an effect of suppressing the side plate portion from being greatly bent and deformed in the front-rear direction or the vertical height direction in which the side plates are separated. Therefore, even if each heat transfer tube is about to undergo widening deformation due to the supply of hot water to each heat transfer tube and the increase in the internal pressure of each heat transfer tube, the side plate portion of the case is greatly deformed accordingly. It suppresses the widening deformation of each heat transfer 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 both ends of each heat transfer tube in the longitudinal direction and the side plate part, or the connection point with the header part or the like. Can be. Therefore, it is possible to eliminate the problem that cracks and the like are likely to occur in various parts 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.
Further, the stepped portion can be easily formed by pressing the side plate portion or the like, the number of parts and the weight do not increase, and the manufacturing cost can be suppressed at a low cost. ..

Further, according to the above 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 because a part of the heat transfer tube has entered the recess of the step push portion provided in the side plate portion. It is possible to do. When the width of this gap is large, a large amount of heating gas flows into this gap, and the heat of the heating gas is dissipated to the outside of the case via the side plate, or the heating gas acts on the heat transfer tube. Without this, a phenomenon such as reaching the exhaust port of the case occurs, and the heat exchange efficiency is lowered. On the other hand, according to the above configuration, it is possible to eliminate such a risk and improve the heat exchange efficiency.
Further, it is possible to increase the length of the heat transfer tube by the amount that the folded tube body portion enters the recess of the step push 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 capacity while suppressing the increase in size of the entire case.

In the present invention, preferably, among the plurality of folded pipe body portions, all the folded pipe body portions located on the side facing and approaching the inner surface of the side plate portion have entered the recess.

According to such a configuration, it is possible to make it more difficult for the heating gas to flow into the recess of the step push portion, and to prevent the heat of the heating gas from being dissipated to the outside of the case through the side plate portion, and also to prevent the recess from being dissipated to the outside of the case. A large amount of heat can be recovered from the heating gas that has flowed into the water by using the folded tube body. Therefore, it is more preferable for increasing the heat exchange efficiency. In addition, it is possible to further promote the lengthening of the heat transfer tube and improve the heat recovery capacity.

In the present invention, preferably, the case is provided with a side plate portion on the other end side located at the other end portion in the width direction, and the side plate portion on the other end side is additionally stepped so that the inner surface side is a recess. A portion is formed, and in the recess of the additional stepped portion, at least a part of the plurality of folded pipe portions that approaches the inner surface of the side plate portion on the other end side of the plurality of folded pipe portions is opposed to the inner surface of the side plate portion. The part is entering.

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, it is suppressed that 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 suppressed to the outside through the side plate portion on the other end side. It is possible to reduce heat dissipation loss.

In the present invention, preferably, the side plate portion is provided on the outer surface portion or the outer surface portion, and the plurality of heat transfer tubes are provided with a pair of header portions for allowing hot water to flow. Of the side plate portions, at least a part of the inter-regional region of the pair of header portions is formed so as to project outward from the side plate portions, and in the lateral width direction, the step push portion and the pair. It overlaps with the header part.

According to such a configuration, it is possible to prevent the pair of header portions from protruding outward from the stepped portion of the side plate portion of the case by a larger dimension in the lateral width direction of the case. Therefore, it is preferable in suppressing the increase in size of the entire heat exchanger.

The hot water supply device provided by the second aspect of the present invention is a hot water supply device including a heat exchanger for heating hot water by recovering heat from the heating gas, and the heat exchanger is the same. , The heat exchanger provided by the first aspect of the present invention is used.

With 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 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 an exploded perspective view of the main part of the heat exchanger shown in FIG. It is a plan sectional view of FIG. FIG. 3 is a sectional view taken along line IV-IV of FIG. FIG. 3 is a sectional view taken along line VV of FIG. It is a schematic cross-sectional view 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 in this figure corresponds to the VI-VI cross section of FIG. It is a top sectional view which shows the schematic structure of another example of a heat exchanger. It is a main part explanatory drawing which shows the example of the operation of the prior art roughly.

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 shown in FIG. 8 are used for elements having the same or similar configurations as those shown in FIG.

The heat exchanger HE shown in FIGS. 1 to 5 includes a case C, a plurality of heat transfer tubes 2 housed in the case C, and a pair of header portions H (Ha, Hb) for entering and discharging water. There is.

The case C includes a case body 1 having a substantially rectangular parallelepiped shape and having both ends opened in the width direction, and a pair of side plate portions 3A and 3B that close the opening portions at both ends of the case body 1. There is. 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 body 1 and the pair of side plate portions 3A and 3B is formed by, for example, pressing or bending a stainless steel plate, and the pair of side plate portions 3A and 3B are both ends of the case body 1. After being fitted to the opening portion, it is joined to the case body 1 by means such as brazing. The rear wall portion 10a and the front wall portion 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 in and out of the case C.
The side plate portions 3A and 3B are provided with a step pushing portion 30 and an additional step pushing portion 31, which will be described later.

Each heat transfer tube 2 has, for example, a meandering shape in a plan view, and includes a plurality of straight tube bodies 22 extending in the lateral width direction of the case C and spaced apart from each other in the front-rear direction of the case C, and the plurality of straight tube bodies. It has a plurality of substantially semicircular folded pipe body portions 23 that are integrally connected to the portion 22 and that connect the ends of the straight pipe body portions 22 that are adjacent to each other. The plurality of heat transfer tubes 2 are laminated 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 ends 2a and 2b (both ends in the longitudinal direction) of each heat transfer tube 2 are in a state of penetrating the side plate 3A of the case C and being pulled out from the inside of the case C to the outside of the side plate 3A. The headers Ha and Hb for entering and discharging water are attached to the water. Since both end portions 2a and 2b are separated from each other in the front-rear direction of the case C, the end portion 2a penetrates the front region of the side plate portion 3A, and the end portion 2b is the rear region of the side plate portion 3A. Penetrates. Both end portions 2a and 2b are fixedly connected to the side plate portion 3A by 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 2a or the end 2b of the plurality of heat transfer tubes 2 is inserted. The header lid member 5 has a joint pipe 53 for connecting an external pipe having an opening 52 for entering water or hot water, and is fitted to the header main body 4 and joined by means such as brazing. To. A chamber 48 communicating with the inside of the end portion 2a or the end portion 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 body 4 are also joined to each other by means such as brazing.

A step pushing portion 30 is provided in a region between both end portions 2a and 2b of the plurality of heat transfer tubes 2 in the side plate portion 3A. The stepped push portion 30 is integrally formed with the side plate portion 3A so that the outer surface side of the side plate portion 3A is a convex portion and the inner surface side is a concave portion 30a, and can be formed by press working on the side plate portion 3A. The step pushing portion 30 has a substantially rectangular shape in a front view of, for example, 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, as the size of the step pushing portion 30 is increased, the rigidity of the side plate portion 3A can be further increased.

The step pushing portion 30 is provided so as to correspond to a plurality of folded pipe body portions 23 of the plurality of heat transfer tubes 2, and among the plurality of folded pipe body portions 23 in the recess 30a of the step pushing portion 30. It is configured to allow at least part of the entry. Preferably, as shown in FIGS. 3 and 4, all the folded pipe body portions 23 located on the side facing and approaching the inner side surface of the side plate portion 3A among the plurality of folded pipe body portions 23 are located in the recess 30a. It is set to enter.

As shown in FIG. 3, in the lateral width direction of the case C, the step pushing 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 the effect of reducing the dimension in which each header portion H projects outward in the width direction with respect to the outer surface portion of the step pushing portion 30.

The side plate portion 3B of the case C is provided with an additional step pushing portion 31. The additional step pushing portion 31 is formed so that the inner surface side of the side plate portion 3B becomes a recess 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 recess 31a. At least a part of the folded pipe body portion 23 that approaches the inner surface of the fold is invading. Preferably, all the folded pipe body portions 23 that approach the inner surface of the side plate portion 3B so as to face each other have entered the recess 31a.

FIG. 6 shows an example of the hot water supply device WH provided with the heat exchanger HE described above.
This hot water supply device WH is mounted on a burner 60 for generating combustion gas, a fan 61 for supplying air for combustion, and a burner case 62, and is a primary heat exchanger for recovering sensible heat from the combustion gas. 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 housed 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. The hot water to be heated is supplied to the header portion H (Ha) for entering water of the heat exchanger HE, passes through the plurality of heat transfer tubes 2 and is heated, and then is primary from the header portion H (Hb) for discharging hot water. It is supplied to the heat transfer tube 71 of the heat exchanger 7, 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 enters the plurality of heat transfer tubes 2 and the internal pressure of these heat transfer tubes 2 becomes high, a force for widening and deforming the plurality of heat transfer tubes 2 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 forming the step pushing portion 30, and the side plate portion 3A is unlikely to be bent and deformed. Since the step pushing 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 less likely to be bent and deformed. Therefore, unlike the configuration shown in FIG. 8, the plurality of heat transfer tubes 2 are less likely to undergo widening deformation accompanied by bending deformation of the side plate portion 3A. When a plurality of heat transfer tubes 2 are greatly widened and deformed, stress is generated at the joints between the heat transfer tubes 2 and the side plate portion 3A, the joints between the heat transfer tubes 2 and the header portion H, and the like, and cracks occur at these locations. However, according to the present embodiment, it is possible to appropriately avoid such a risk and improve the durability performance of the heat exchanger HE.

The combustion gas flowing into the case C from the air supply port 11 acts on the plurality of heat transfer tubes 2 and then reaches the exhaust port 12, but in this process, some of the combustion gas is recessed in the step push portion 30. It flows into 30a. On the other hand, a part of the plurality of folded pipe body portions 23 has entered the recess 30a, and preferably all the folded pipe body portions 23 approaching the side plate portion 3A have entered. It is possible to prevent a large gap from being formed between the folded pipe body portion 23 and the side plate portion 3A. It is possible to efficiently recover heat from the combustion gas flowing into the recess 30a by the plurality of folded pipe body portions 23.

Further, according to the configuration in which the folded tube body portion 23 of the heat transfer tube 2 has entered the recess 30a, the size of the heat transfer tube 2 can be increased as compared with 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. Therefore, the heat exchanger HE can be made excellent in heat exchange efficiency.

As described above, the other side plate portion 3B of the case C is provided with the additional step pressing portion 31, so that 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 a plurality of folded pipe body portions 23 have entered the recess 31a of the additional step pushing portion 31, the folded pipe body portion 23 has entered the recess 30a of the step pushing portion 30 described above. Similar to the case, it is possible to efficiently recover heat from the combustion gas even in the region near the side plate portion 3B, and it is possible to obtain excellent heat exchange efficiency.

FIG. 7 shows another embodiment of the heat exchanger. In the figure, elements that are the same as or similar to those of the embodiment are designated by the same reference numerals as those of the embodiment, and duplicate description will be omitted.

In the embodiment shown in FIG. 7, an outwardly convex step-pushing portion 32 for forming a header is integrally formed on the side plate portion 3A of the case C, and each header portion H has a header formed on the step-pushing portion 32. The member 5A is formed by being externally fitted and joined. Both end portions 2a and 2b of each heat transfer tube 2 are joined through the side plate portion 3A. A step pushing portion 30 is provided in a region between the pair of header portions H.

In the present embodiment, the side plate portion 3A is formed with a pair of stepped push portions 32 for forming each header portion H, and the step push portions 32 are both end portions 2a and 2b of the heat transfer tube 2. A step-pushing portion formed in a region to which the heat transfer tube 2 is connected, which is a portion for simplifying the formation of the header portion H, and is a step-pushing 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 by using the side plate portion of the case . Also, for the side plate section 3B, it may be configured not to form a stepped pressing portion.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each part of the heat exchanger and the hot water supply device according to the present invention can be variously redesigned within the scope intended by the present invention.

In the present invention, the end portion of the heat transfer tube does not have to 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, this member may be used. , The ends of the heat transfer tubes may be connected (for example, Patent Documents 1 and 2 have a similar configuration).

The stepped portion (stepped portion 30) for suppressing widening deformation of the heat transfer tube in the present invention can have a shape other than a substantially rectangular shape in the front view thereof. Further, the size of the front view is preferably as large as possible, but is not limited to this, and may be a small size. Further, a plurality of step push portions may be provided. For example, a configuration is adopted in which elongated rectangular step push 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. Such a point is the same for the additional step push portion.

The heat transfer tube is not limited to a meandering one, 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 case is laminated in the vertical height direction, and may be, for example, a structure in which the case is laminated in the front-rear direction. In this case, both ends of each heat transfer tube in the longitudinal direction are usually arranged so as to be separated from each other in the vertical height direction, and a step pushing portion intended by the present invention is formed in a region between them. ..

The present invention is not limited to the heat exchanger for latent heat recovery, and can be applied regardless of the type such as sensible heat recovery or latent heat recovery. Further, the case is not limited to the one in which the heat transfer tubes constituting one system of water channels are housed in one case (one can and one water channel type), and the plurality of heat transfer tubes constituting one system of water channels are housed in one case. It can also be configured as a can (one can, two waterways, or the like, one can, multiple waterways type).
The heating gas is not limited to the combustion gas generated by the burner, and can be, for example, high-temperature exhaust gas discharged from a cogeneration system or the like.

C Case HE Heat exchanger WH Hot water supply device H (Ha, Hb) Header part 1 Case body 2 Heat transfer tubes 2a, 2b Ends (of heat transfer tubes)
22 Straight tube body 23 Folded tube body 3A Side plate (on one end side of the case)
3B side plate (on the other end of the case)
30 Step push part 30a Recess (of step push part)
31 Additional step push part 31a Recess (of the additional step push part)

Claims (5)

A case where a heating gas is supplied inside and a side plate is provided at one end in the width direction.
A plurality of heat transfer tubes housed in this case and connected to the side plate portion or a member joined to the side plate portion so that both ends in the longitudinal direction are separated from each other in the front-rear direction or the vertical height direction.
Is a heat exchanger equipped with
In the region between both ends of the plurality of heat transfer tubes in the longitudinal direction of the side plate portions, a part of the side plate portion is outside the case rather than a general portion which is a non-step pushing portion of the side plate portion. A stepped push portion that partially protrudes toward the side, has a convex portion on the outer surface side, and is a concave portion on the inner surface side is integrally formed.
Each of the plurality of heat transfer tubes includes a plurality of straight tube portions that are arranged side by side at intervals in the front-rear or vertical direction and extend in the lateral width direction, and a plurality of folds that connect the ends of the plurality of straight tube portions. It is configured to have a tube body and
A heat exchanger, characterized in that at least a part of the plurality of folded pipe bodies has entered the recess of the stepped push portion. The heat exchanger according to claim 1.
A heat exchanger in which all of the folded pipe body portions located on the side facing and approaching the inner surface of the side plate portion among the plurality of folded pipe body portions have entered the recess. The heat exchanger according to claim 1 or 2.
The case includes a side plate portion on the other end side located at the other end portion in the width direction.
An additional step pushing portion having an inner surface side as a recess is formed in the side plate portion on the other end side, and in the recess of the additional step pushing portion, among the plurality of folded pipe body portions, the said A heat exchanger in which at least a part of the folded pipe body that approaches the inner surface of the side plate on the other end side is inserted. The heat exchanger according to any one of claims 1 to 3.
It is provided on the outer surface portion or the outer surface portion of the side plate portion, and is provided with a pair of header portions for allowing the plurality of heat transfer tubes to flow hot water.
The step pushing portion is formed so that at least a part of the inter-regional region of the pair of header portions of the side plate portions projects outward of the side plate portions, and the step portion is formed in the lateral width direction. A heat exchanger in which the push portion and the pair of header portions overlap each other. A hot water supply device equipped with a heat exchanger for heating hot water by recovering heat from the heating gas.
A hot water supply device, wherein the heat exchanger according to any one of claims 1 to 4 is used as the heat exchanger.

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