Heat exchanger and hot water apparatus including the same

Abstract

To provide a heat exchanger capable of properly eliminating the risk of boiling of hot water in an upstream end in a heating gas flow direction of a flat or elliptical heat transfer tube.SOLUTION: A baffle plate B disposed in a flat or elliptical heat-transfer pipe 3 of a heat-exchanger HE includes a plurality of first and second projecting pieces 5a to 5c. The plurality of first protruding piece portions 5a being capable of guiding water and / or hot water which has moved forward to flow toward heat upstream end portion 31 of heat transfer tube 3 which is located upstream in the heating-gas flow direction, the plurality of second protruding pieces 5b, 5c are located closer to upstream end 31 than the plurality of first protruding pieces 5a, and the water guided by the plurality of first protruding pieces 5b flows into and out of the plurality of first gaps 61 formed between the plurality of second protruding pieces 5b, 5c and the inner surface of upstream end 31, and the plurality of second gaps 62 formed between the plurality of second protruding pieces, 5c. 5a.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a heat exchanger and a hot water apparatus such as a hot water heater including the heat exchanger. [Background technology]

[0002] As a heat exchanger constituting a hot water device, for example, there is a configuration in which a baffle plate is arranged inside a heat transfer tube (see, for example, Patent Documents 1 to 4). The heat transfer tube is placed in a case to which a heating gas such as combustion gas is supplied, and hot water to be heated is supplied into the heat transfer tube. The baffle plate is a member for generating turbulence in the heat transfer tube, which helps to improve heat exchange efficiency.

[0003] However, the above-mentioned conventional techniques still have room for improvement as follows.

[0004] For example, a flat or elliptical heat transfer tube whose vertical width is greater than its horizontal width may be used as the heat transfer tube, with one end of the heat transfer tube in the vertical width direction being the upstream end for heating, which is the upstream end in the direction of the flow of heating gas. In this case, the upstream end of the heat transfer tube is heated to a high temperature, which makes it easy for hot water to locally boil inside. Boiling water generates bubbles in the heat transfer tube, resulting in a so-called partial dry-heating condition, which can damage the heat transfer tube and significantly reduce heat exchange efficiency, so it is desirable to avoid this as much as possible.

[0005] In contrast, the conventional technology described above can only generate turbulence in a region near the center of the heat transfer tube, or generate a flow of hot water from one end to the other end in the longitudinal direction of the heat transfer tube. In other words, it is difficult to effectively generate turbulence in the upstream heating end of the heat transfer tube. As a result, there is a risk of the hot water boiling in the upstream heating end of the heat transfer tube, and there is room for improvement in this regard. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-open No. 47-015743 [Patent Document 2] Patent No. 6357480 [Patent Document 3] Special Publication No. 2019-510952 [Patent Document 4] Japanese Patent Application Laid-Open No. 2018-100790 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention was devised under the circumstances described above, and its object is to provide a heat exchanger that can appropriately eliminate the risk of hot water boiling within the upstream end of the heat transfer tube in the direction of heating gas flow when the heat transfer tube is flat or elliptical, and a hot water device equipped with the same. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following technical solutions.

[0009] A heat exchanger according to a first aspect of the present invention comprises a flat or elliptical heat transfer tube, the vertical width of which is greater than the horizontal width, and the heat transfer tube is disposed in a case to which a heating gas is supplied, and into which hot or cold water to be heated is supplied, and a baffle plate disposed within the heat transfer tube, the baffle plate comprising a baffle plate main body extending in a longitudinal direction x of the heat transfer tube, and a plurality of protruding pieces protruding from the baffle plate main body in a lateral direction y of the heat transfer tube, This heat exchanger has a configuration in which the heating gas flows in the vertical width direction z of the heat transfer tube, and the multiple protruding pieces include multiple first and second protruding pieces each arranged at intervals in the longitudinal direction x, and the multiple first protruding pieces are capable of guiding hot water that flows toward these multiple first protruding pieces so that it flows toward the heating upstream end, which is upstream of the heating gas flow direction of the heat transfer tube, and the multiple second protruding pieces are located closer to the heating upstream end than the multiple first protruding pieces, and a multiple first gaps are formed between the multiple second protruding pieces and the inner wall surface of the heating upstream end, and a multiple second gaps are formed between the multiple second protruding pieces, and the hot water guided toward the heating upstream end by the multiple first protruding pieces can flow into and out of the multiple first and second gaps.

[0010] This configuration provides the following effects. That is, when hot water that flows into the heat transfer tube reaches the location where the first protruding piece is provided, it is guided to flow toward the heating upstream end of the heat transfer tube. Some of this hot water then passes through second gaps between the multiple second protruding pieces, and flows into first gaps between the second protruding piece and the inner wall surface of the heating upstream end of the heat transfer tube. Furthermore, the hot water that flows into the first gap in this way passes through other second gaps, and flows out of the first gap. At each location where multiple first and second protruding pieces are provided, hot water actively flows into and out of the first gap and the second gap in the manner described above, thereby generating sufficient and effective turbulence in the hot water within the heating upstream end of the heat transfer tube. As a result, it is possible to avoid boiling of hot water in the upstream end of the heat transfer tube, which is heated to a fairly high temperature by the heating gas, thereby appropriately preventing problems such as thermal damage to the heat transfer tube and improving heat exchange efficiency. The present invention is more effective when the heat transfer tube is made of a material with low thermal conductivity, such as stainless steel.

[0011] In the present invention, preferably, the baffle plate main body is constructed using a metal plate, the plurality of first protruding pieces are cut-out portions of the metal plate, and the plurality of second protruding pieces are portions where one side edge of the metal plate is bent.

[0012] According to this configuration, the baffle plate can be easily and accurately manufactured by pressing a metal plate, which is preferable in terms of reducing manufacturing costs.

[0013] In the present invention, preferably, the plurality of first protruding pieces have a guide surface that is inclined and faces upstream in the hot water flow direction so that the more downstream in the hot water flow direction within the heat transfer tube the closer to the heating upstream end.

[0014] According to this configuration, the hot and cold water flowing inside the heat transfer tube can be made to flow efficiently toward the heating upstream end of the heat transfer tube by the plurality of first projecting pieces.

[0015] In the present invention, preferably, the plurality of second protruding pieces are provided as a plurality of second 1 protruding pieces, and these second 1 protruding pieces are arranged so as to overlap the plurality of first protruding pieces in the longitudinal direction x, and protrude in the width direction y in a direction opposite to the direction in which the plurality of first protruding pieces protrude from the baffle plate main body.

[0016] With this configuration, the hot water flowing into the upstream heating end of the heat transfer tube flows along the inner wall surface of the upstream heating end due to the guiding action of the multiple first protrusions, and collides with the second protrusions along the way, creating a vortex (as shown by arrow Nd in Figure 3(b)). This is even more desirable for promoting turbulence in the hot water.

[0017] In the present invention, preferably, the plurality of second protruding pieces are provided instead of or in addition to the plurality of second protruding pieces, and these plurality of second protruding pieces are arranged so as not to overlap with the plurality of first protruding pieces in the longitudinal direction x, and protrude in the same direction as the direction in which the plurality of first protruding pieces protrude from the baffle plate main body in the width direction y.

[0018] With this configuration, hot water flowing into the heating upstream end of the heat transfer tube due to the guiding action of the multiple first protruding pieces flows into and out of the first gap between the multiple second 1 protruding pieces and the inner wall surface of the heating upstream end of the heat transfer tube, thereby properly turbulentizing the flow.

[0019] In the present invention, preferably, the plurality of first protruding pieces are provided on one side of the baffle plate main body in the width direction y, and the opposite side is provided with a plurality of front-to-back reversal protruding pieces that correspond to the plurality of first protruding pieces when the baffle plate is reversed so that the front and back are interchanged in the longitudinal direction x.

[0020] With this configuration, when assembling a heat exchanger by inserting a baffle plate into a heat transfer tube, the insertion direction of the baffle plate into the heat transfer tube (front or back in the longitudinal direction x) does not matter. This simplifies the assembly work of the heat exchanger. It also prevents assembly errors due to inserting the baffle plate in the wrong direction. Furthermore, the multiple front-to-back reversal protrusions help to generate turbulent flow of hot and cold water inside the heat transfer tube, which is even more desirable for improving heat exchange efficiency.

[0021] In the present invention, preferably, the baffle plate further includes a plurality of up-down inversion protruding pieces that have rotational symmetry about the center line of the heat transfer tube in the vertical width direction z relative to the plurality of first and second protruding pieces and the plurality of front-to-back inversion protruding pieces, and when the baffle plate is inverted in the up-to-down direction as the vertical width direction z, the plurality of up-to-down inversion protruding pieces are configured to correspond to the plurality of first and second protruding pieces and the plurality of front-to-back inversion protruding pieces.

[0022] This configuration allows the baffle plate to be inserted into the heat transfer tubes in any orientation when assembling the heat exchanger. This simplifies the assembly process and also prevents assembly errors due to incorrect orientation of the baffle plate. Furthermore, the multiple inversion projections help to generate turbulence in the hot and cold water, which is advantageous for improving heat exchange efficiency.

[0023] In the present invention, preferably, the plurality of first and second protruding pieces, the plurality of front-to-back inversion protruding pieces, and the plurality of up-to-down inversion protruding pieces are arranged above or below a certain region near the center of the vertical width direction z of the heat transfer tube so as to avoid the certain region.

[0024] With this configuration, hot water flowing through a certain region of the heat transfer tube near the center in the vertical width direction z does not directly contact the various protruding pieces. This is therefore preferable in terms of preventing excessive flow resistance within the heat transfer tube. Furthermore, because the various protruding pieces are located above or below a certain region of the heat transfer tube near the center in the vertical width direction z, it is possible to more efficiently generate turbulent hot water at both ends of the heat transfer tube in the vertical width direction z (including the upstream end for heating).

[0025] A water heating device provided by a second aspect of the present invention comprises a heating gas supply means and a heating gas supply means. A hot water device comprising a heat exchanger that recovers heat from heating gas supplied from a gas supply means to heat hot water, characterized in that the heat exchanger is a heat exchanger provided by the first aspect of the present invention.

[0026] According to this configuration, the same effects as those described for the heat exchanger provided by the first aspect of the present invention can be obtained.

[0027] Other features and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a plan cross-sectional view showing an example of a heat exchanger according to the present invention. [Figure 2] (a) is a cross-sectional view showing an example of the schematic configuration of a hot water device equipped with the heat exchanger shown in Figure 1 (the cross-sectional view of the heat exchanger corresponds to the IIa-IIa cross-sectional view of Figure 1), and (b) is an enlarged cross-sectional view of a portion of (a). [Figure 3] 1 (a) is a cross-sectional view taken along line IIIa-IIIa in FIG. 1 (fins are omitted), and FIG. 1 (b) is an enlarged cross-sectional view taken along line IIIb-IIIb in FIG. 1 (a). [Figure 4] (a) is a perspective view of a baffle plate of the heat exchanger shown in Figures 1 to 3, (b) is a partially omitted front view of (a), (c) is a plan view of (b), (d) is a side view of (b), (e) is a IVe-IVe cross-sectional view of (b), and (f) is a IVf-IVf cross-sectional view of (b). [Figure 5] FIG. 10 is a cross-sectional view of a main part showing another embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view of a main part showing another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0030] The water heating device WH shown in FIG. 2 is configured as a hot water supply device, and is a combination of a heat exchanger HE to which the present invention is applied and a burner 1. The burner 1 is a gas burner that burns, for example, fuel gas to generate combustion gas, and corresponds to an example of the heating gas supply means referred to in the present invention. The combustion gas corresponds to an example of the heating gas referred to in the present invention.

[0031] The heat exchanger HE includes a case 2 having a plurality of side wall portions 20a, 20b of a generally rectangular cylindrical shape with both upper and lower surfaces open, a plurality of heat transfer tubes 3 arranged within the case 2, and a plurality of baffle plates B arranged within each of the plurality of heat transfer tubes 3. The case 2 of the heat exchanger HE is disposed above the burner 1, and the combustion gas generated by the burner 1 is supplied upward from below into the case 2. In this embodiment, the combustion gas flows upward in the heat exchanger HE (corresponding to the heating gas flow direction).

[0032] Each heat transfer tube 3 is flat with a vertical width La greater than a horizontal width Lb (see FIG. 2(b)), with both side wall portions 30 in the horizontal width direction y being flat, and the wall portions of both lower and upper end portions 31, 32 in the vertical width direction z being made of metal and having a substantially semicircular cross section. The multiple heat transfer tubes 3 are entirely or mostly disposed within the case 2, with the tubes 3 being supported by the side wall portions 20b of the case 2 and arranged substantially parallel to each other at intervals in a direction (horizontal width direction y) intersecting the longitudinal direction x of each heat transfer tube 3 (see also FIG. 1). In this embodiment, the length direction x and the width direction y are both horizontal directions, and the length direction z is the up-down height direction (vertical direction).

[0033] Water inlet and outlet headers 7a, 7b and multiple heat transfer tube connecting headers 7c are provided at both ends of the multiple heat transfer tubes 3, and hot water supplied to the water inlet 70a of the water inlet header 7a passes through the multiple heat transfer tube connecting headers 7c, sequentially through each of the multiple heat transfer tubes 3, and finally reaches the hot water outlet header 7b. In this process, the hot water is heated by the combustion gas, and the hot water (warm water) generated by this heating is discharged to the desired destination from the outlet 70b of the hot water outlet header 7b. The plurality of heat transfer tubes 3 are configured as so-called fin pipes, and are joined to a plurality of plate-type fins 39 for heat recovery arranged in the case 2 while being inserted through these fins 39 .

[0034] Each baffle plate B is a member for making hot and cold water flowing through each heat transfer tube 3 turbulent, and is formed by pressing a metal plate 4a, and includes a baffle plate main body 4 extending in the longitudinal direction x of the heat transfer tube 3. Also, as parts connected to this baffle plate main body 4, it includes a plurality of first protruding pieces 5a, a plurality of second protruding pieces 5b, 5c, a plurality of front-to-back reversing protruding pieces 5d, and a plurality of up-down reversing protruding pieces 5a'-5d'.

[0035] The baffle plate main body 4 is a thin plate-like portion extending in the longitudinal direction x of each heat transfer tube 3, forming the main part of the baffle plate B, and its overall length is approximately the same as that of each heat transfer tube 3. The vertical width Lc (see FIGS. 4(a) and 4(b)) of both ends of the baffle plate main body 4 in the longitudinal direction x is approximately the same as the inner width of the heat transfer tube 3 in the vertical width direction z, so that when the baffle plate B is inserted into the heat transfer tube 3, there is no significant play at the positions of the both ends.

[0036] 3, when hot water flows from left to right inside the heat transfer tube 3, the multiple first and second protruding pieces 5a-5c are portions that turbulently circulate the hot water at the heating upstream end 31 side of the heat transfer tube 3. Of both end portions 31, 32 of the heat transfer tube 3 in the vertical width direction z, the heating upstream end 31 is the end that is upstream in the combustion gas flow direction.

[0037] Each of the first protruding pieces 5a is a cut-and-raised portion of the metal plate 4a that constitutes the baffle plate main body 4. More specifically, each of the first protruding pieces 5a is a portion that forms an opening 40a in the metal plate 4a, and has one side edge that stands upright to one side in the width direction y (the front side in Figures 3(a) and 4(a) and (b)). Each first protruding piece 5a is positioned offset toward the heating upstream end 31 from the center line CL in the vertical width direction z of the heat transfer tube 3 and the baffle plate B. Furthermore, each first protruding piece 5a is inclined at an appropriate angle α with respect to the vertical width direction z so that it is positioned closer to the heating upstream end 31 the more downstream in the hot water flow direction within the heat transfer tube 3, and has a guide surface 50 facing upstream in the hot water flow direction. 3(a), it is possible to guide the hot or cold water that has advanced toward the first protruding piece 5a so that it flows toward the heating upstream end 31 of the heat transfer tube 3. The multiple first protruding pieces 5a are arranged at intervals in the longitudinal direction x of the heat transfer tube 3.

[0038] The second protruding piece 5b (second 1st protruding piece) and the second protruding piece 5c (second 2nd protruding piece) are both bent portions of one side edge of the metal plate 4a that constitutes the baffle plate main body 4. More specifically, they are as follows.

[0039] That is, each second protruding piece 5b protrudes from the upstream side edge of the baffle plate main body 4 in the combustion gas flow direction to one side in the width direction y (the side opposite to the first protruding piece 5a) and has an appropriate length Le in the longitudinal direction x. Each second protruding piece 5b overlaps with each first protruding piece 5a (except for the leftmost protruding piece 5a) in the longitudinal direction x of the heat transfer tube 3 and is arranged at intervals in the longitudinal direction x of the heat transfer tube 3 so as to be located closer to the heating upstream end 31 of the heat transfer tube 3 than the multiple first protruding pieces 5a. A first gap 61 (61b) is formed between each second protruding piece 5b and the inner wall surface of the heating upstream end 31, and a second gap 62 (62b) is formed between each of the second protruding pieces 5b. These first and second gaps 61, 62 correspond to flow paths for turbulent flow of hot and cold water.

[0040] Like each second protruding piece 5b, each second protruding piece 5c protrudes in the width direction y from the upstream side edge of the baffle plate main body 4 in the combustion gas flow direction, and has a length Lf in the longitudinal direction x that is approximately the same as the length Le of each second protruding piece 5b. However, the protruding direction of each second protruding piece 5c in the width direction y is opposite to that of each second protruding piece 5b. Furthermore, each second protruding piece 5c is located between the multiple second protruding pieces 5b in the longitudinal direction x of the heat transfer tube 3, and does not overlap with each first protruding piece 5a. Similar to the second protruding pieces 5b, the second protruding pieces 5c are also arranged at intervals in the longitudinal direction x of the heat transfer tube 3, and first gaps 61 (61c) are formed between the second protruding pieces 5c and the inner wall surface of the heating upstream end 31. Second gaps 62 (62c) are also formed between each of the second protruding pieces 5c. As shown by arrow Na in Figure 3, the hot water guided by the first protruding piece 5a to the heating upstream end 31 of the heat transfer tube 3 can then flow into and out of the first and second gaps 61, 62 as shown by arrows Nb and Nc. Also, as shown by arrow Nd, a portion of the hot water forms a vortex.

[0041] The plurality of front-reversal projections 5d are portions that essentially become the plurality of first projections 5a when the baffle plate B is reversed in the longitudinal direction x. The front-reversal projections 5d are provided on one side of the baffle plate main body 4 in the width direction y, opposite the first projections 5a (the far side in FIGS. 3(a) and 4(a) and (b)), and are configured as portions that have rotational symmetry (dual symmetry) around an axis extending in the vertical width direction z with respect to the first projections 5a. The front-reversal projections 5d are formed by the same means as the first projections 5a, and are portions that rise from one side edge of the opening 40d provided in the baffle plate main body 4. The second protruding pieces 5b and 5c have rotational symmetry around an axis extending in the vertical width direction z, similar to the first protruding piece 5a and the front-rear reversing protruding piece 5d.

[0042] The plurality of protruding pieces 5a'-5d' for up-down inversion are portions that essentially become the plurality of protruding pieces 5a-5d (first and second protruding pieces 5a-5c, front-reversal inversion protruding piece 5d) when the baffle plate B is inverted upside down. These plurality of protruding pieces 5a'-5d' for up-down inversion are provided above the center line CL in the vertical width direction z of the baffle plate main body 4, and are configured as portions that have rotational symmetry (2-fold symmetry) about the center line CL with respect to the plurality of protruding pieces 5a-5d. The plurality of protruding pieces 5a'-5d' for up-down inversion are formed by the same means as the first and second protruding pieces 5a-5c and the front-reversal inversion protruding piece 5d. Reference numerals 40a' and 40d' denote openings for forming the protruding pieces 5a' and 5d' for up-down inversion as cut-and-raised portions, respectively.

[0043] The multiple protruding pieces 5a-5d and the multiple up-down inversion protruding pieces 5a'-5d' are arranged below or above a certain region (region of width Ld) close to the center line CL in the vertical width direction z of the heat transfer tube 3 so as to avoid the certain region. This configuration has the effect of reducing the flow resistance of hot and cold water flowing close to the center line CL of the heat transfer tube 3.

[0044] Next, the operation of the heat exchanger HE and the water heating device WH will be described.

[0045] First, when the hot water device WH is operated, as described above, the combustion gas generated by the burner 1 is supplied to the case 2 of the heat exchanger HE, acts on each heat transfer tube 3, and passes through each heat transfer tube 3. In this case, among the various parts of each heat transfer tube 3, the upstream end 31 is the part that is most likely to be heated to a high temperature by the combustion gas, and is therefore more likely to cause boiling of the water than other parts such as the downstream end 32 in the direction of combustion gas flow.

[0046] In contrast, in the heat exchanger HE of this embodiment, as shown in Fig. 3, of the hot water that flows into each heat transfer tube 3, a portion of the hot water that flows toward the heating upstream end 31 from the center line CL in the vertical width direction z is guided by the guide action of each first protruding piece 5a and continues toward the heating upstream end 31, as indicated by arrow Na. This hot water then flows into and out of the first and second gaps 61, 62 formed by the multiple second protruding pieces 5b, 5c, as indicated by arrows Nb and Nc, thereby turbulentizing the hot water. At this time, a vortex of the hot water can also be generated in and near the first gap 61, as indicated by arrow Nd in Fig. 3(b).

[0047] The above-described action sufficiently and effectively turbulently circulates hot and cold water within the heating upstream end 31 of each heat transfer tube 3. As a result, boiling of hot and cold water is avoided within the heating upstream end 31 of each heat transfer tube 3, which is heated to the highest temperature, and thermal damage to each heat transfer tube 3 is appropriately prevented, and the heat exchange efficiency of the heat exchanger HE can be improved. Furthermore, the plurality of front-to-back reversal projection pieces 5d and the plurality of up-to-down reversal projection pieces 5a' to 5d' also turbulently flow the hot and cold water, which further promotes turbulence in the hot and cold water flow in each heat transfer tube 3, which is preferable for improving the heat exchange efficiency.

[0048] The baffle plate B of this embodiment is provided with a plurality of front-to-back reversible protruding pieces 5d, and even if the insertion direction of the baffle plate B into the heat transfer tube 3 (front to back in the longitudinal direction x) is set opposite to the direction shown in Figure 3(a), the plurality of front-to-back reversible protruding pieces 5d essentially become a plurality of first protruding pieces 5a, and hot water is appropriately guided toward the heating upstream end 31 where the plurality of second protruding pieces 5b, 5c are located. Thus, according to this embodiment, assembly errors due to incorrect insertion direction of the baffle plate B are eliminated, and the assembly work of the heat exchanger HE is also facilitated.

[0049] Furthermore, the baffle plate B is provided with a plurality of protruding pieces 5a' to 5d' for up-down inversion, and even if the up-down orientation of the baffle plate B is set opposite to the orientation shown in Figure 3(a) when the baffle plate B is inserted into the heat transfer tube 3, the plurality of protruding pieces 5a' to 5d' for up-down inversion essentially become the plurality of first and second protruding pieces 5a to 5c and the plurality of protruding pieces for front-back inversion 5d. This eliminates assembly errors due to incorrect orientation of the baffle plate B, further facilitating the assembly work of the heat exchanger HE.

[0050] In this embodiment, among the multiple upside-down projections 5a'-5d', the projections 5a'-5c' corresponding to the first and second projections 5a-5c exert an action similar to the action of the first and second projections 5a-5c in turbulentizing the hot water in the heating upstream end 31, thereby turbulently turbulizing the hot water in the end 32. Portions of each heat transfer tube 3 other than the heating upstream end 31, such as the end 32 downstream in the combustion gas flow direction, are exposed to combustion gas whose temperature has been reduced by heat recovery, and therefore have a lower heating temperature than the heating upstream end 31. Therefore, while the turbulence described for the hot water in the heating upstream end 31 is not essentially necessary in the end 32, even if the end 32 were to be heated to a high temperature, boiling of the hot water in the end 32 is appropriately prevented, thereby helping to increase the reliability of boiling prevention.

[0051] 5 and 6 show another embodiment of the present invention. In these figures, elements that are the same as or similar to those in the previous embodiment are given the same reference numerals as in the previous embodiment, and redundant explanations will be omitted.

[0052] The baffle plate Ba shown in FIG. 5 includes a plurality of second protruding pieces 5b (second first protruding pieces) in addition to a plurality of first protruding pieces 5a. The baffle plate Bb shown in FIG. 6 includes a plurality of second projecting pieces 5c (second projecting pieces) in addition to a plurality of first projecting pieces 5a. However, neither of the baffle plates Ba nor Bb has any other protruding pieces than those mentioned above. In either of Figures 5 and 6, it is possible to turbulently flow hot and cold water within the heating upstream end 31 of the heat transfer tube 3, thereby achieving the effect intended by the present invention, and it is possible to configure the second protruding piece to include only one of the two types of second protruding piece 5b, 5c. As can be understood from the above embodiment, in the present invention, the plurality of front-to-back reversing protruding pieces 5d and the plurality of up-to-down reversing protruding pieces 5a' to 5d' may be omitted in whole or in part.

[0053] The present invention is not limited to the above-described embodiment, and the specific configurations of the heat exchanger and the hot water device according to the present invention can be freely modified in various ways within the intended scope of the present invention.

[0054] The heat transfer tubes covered by the present invention may be flat or elliptical in shape, as long as the vertical width is greater than the horizontal width, and the specific ratio of the vertical width to the horizontal width is not important. Furthermore, the heat transfer tube is not limited to a flat tube with a flat side wall, but may also be a flat or elliptical tube with a curved side wall. The vertical width direction and horizontal width direction in the present invention are not limited to the up-down direction and the horizontal direction. In the above-described embodiment, the flat heat transfer tubes are set in an upright position in the vertical direction, but they may also be set in a different position, for example, lying on their side. In this case, the vertical width direction z is the horizontal direction, and the horizontal width direction y is the up-down direction. Instead of combustion gas, the heating gas can be high-temperature exhaust gas generated in a cogeneration system, for example. The flow direction of the heating gas is not limited to upward, but can also be set to other directions, such as downward (for example, by providing a burner above the heat exchanger). The hot water system of the present invention is not limited to a hot water system for general hot water supply, but may also be configured as a hot water system for baths, a hot water system for heating, or a hot water system for melting snow. [Explanation of symbols]

[0055] HE heat exchanger WH water heater B,Ba baffle plate 1 Burner (heating gas supply means) 2 cases 3 Heat transfer tubes 31 Heating upstream end (of heat transfer tube) 4 Baffle plate body 4a metal plate 5a First protruding piece 5b Second protruding piece (second 1 protruding piece) 5c Second protruding piece (second 2 protruding piece) 5d Protruding piece for forward / backward reversal 5a'~5d' Protruding piece for vertical reversal 61,62 First and second gaps

Claims

1. a flat or elliptical heat transfer tube disposed in a case to which a heating gas is supplied, into which hot or cold water to be heated is supplied, and whose vertical width is greater than its horizontal width; a baffle plate disposed within the heat transfer tube; It is equipped with the baffle plate includes a baffle plate main body extending in a longitudinal direction x of the heat transfer tube, and a plurality of protruding pieces protruding from the baffle plate main body in a width direction y of the heat transfer tube, A heat exchanger in which the heating gas flows in a vertical width direction z of the heat transfer tube, The plurality of protruding pieces include a plurality of first protruding pieces and a plurality of second protruding pieces that are arranged at intervals in the longitudinal direction x, The plurality of first protruding pieces are capable of guiding the hot water that has advanced toward the plurality of first protruding pieces so that the hot water flows toward the upstream end of the heat transfer tube, which is upstream in the heating gas flow direction, A heat exchanger characterized in that the multiple second protruding pieces are located closer to the heating upstream end than the multiple first protruding pieces, multiple first gaps are formed between the multiple second protruding pieces and the inner wall surface of the heating upstream end, and multiple second gaps are formed between the multiple second protruding pieces, and hot water guided closer to the heating upstream end by the multiple first protruding pieces can flow into and out of the multiple first and second gaps.

2. 2. The heat exchanger of claim 1, The baffle plate body is made of a metal plate, the plurality of first protruding pieces are cut-and-raised portions of the metal plate, The plurality of second protruding pieces are bent portions of one side edge of the metal plate.

3. 2. The heat exchanger of claim 1, A heat exchanger in which the multiple first protruding pieces have guide surfaces that are inclined so that the more downstream in the direction of hot water flow within the heat transfer tube they are positioned closer to the upstream heating end, and that face upstream in the direction of hot water flow.

4. 4. The heat exchanger according to claim 3, The plurality of second protruding pieces include a plurality of second protruding pieces, A heat exchanger in which these multiple second 1 protruding pieces are arranged to overlap the multiple first protruding pieces in the longitudinal direction x, and protrude in the width direction y in a direction opposite to the direction in which the multiple first protruding pieces protrude from the baffle plate main body.

5. 5. The heat exchanger according to claim 4, As the plurality of second protruding pieces, a plurality of second second protruding pieces are provided instead of or in addition to the plurality of second first protruding pieces, a heat exchanger in which these second protruding pieces are arranged so as not to overlap with the first protruding pieces in the longitudinal direction x, and protrude in the same direction as the direction in which the first protruding pieces protrude from the baffle plate main body in the width direction y.

6. 6. The heat exchanger according to claim 5, The baffle plate body has a plurality of first protruding pieces on one side in the width direction y, and a plurality of front-rear reversed portions on the opposite side, which correspond to the plurality of first protruding pieces when the baffle plate is inverted so that the front and rear of the baffle plate are reversed in the longitudinal direction x. A heat exchanger provided with a conversion protruding piece portion.

7. 7. The heat exchanger according to claim 6, the baffle plate further includes a plurality of up-down inversion protruding pieces that are rotationally symmetric about a center line in a vertical width direction z of the heat transfer tube with respect to the plurality of first and second protruding pieces and the plurality of front-rear inversion protruding pieces, A heat exchanger configured such that when the baffle plate is inverted in the vertical direction, which is the vertical width direction z, the multiple up-down inversion protruding pieces correspond to the multiple first and second protruding pieces and the multiple front-to-back inversion protruding pieces.

8. 8. The heat exchanger of claim 7, a heat exchanger, wherein the plurality of first and second protruding pieces, the plurality of front-to-back inversion protruding pieces, and the plurality of up-to-down inversion protruding pieces are arranged above or below a certain region near the center of the heat transfer tube in the vertical width direction z so as to avoid the certain region.

9. a heating gas supply means; a heat exchanger that recovers heat from the heating gas supplied from the heating gas supply means to heat water; A hot water device comprising: A water heating system comprising the heat exchanger according to any one of claims 1 to 8 as the heat exchanger.

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