JP2017194247A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger improved in heat transferring efficiency by effectively utilizing heat transfer tubes as a whole.SOLUTION: In a heat exchanger (20) including a substantially rectangular parallelepiped case (21) and a heat transfer tube unit (22) disposed inside of the case (21), and provided with an introduction opening portion (33) for introducing a combustion gas, on one end portion side of a bottom plate (21a) of the case (21), and further a discharge opening portion (35) for discharging the combustion gas, at the other end portion side of a top plate (26) of the case (21), the heat transfer tube unit (22) is formed in a plurality of stages by winding a plurality of heat transfer tubes (22a) into the elliptical shape or rectangular shape in a plane view, spacers (30) are disposed to partially partition a gap between the heat transfer tubes (22a) adjacent to each other in a vertical direction, the discharge opening portion (35) is formed on a position separating from the other end portion of the case (21) by a prescribed distance of a horizontal width of the plurality of arranged heat transfer tubes or more, and a part (36a) of the opening end portion at the other end portion side, of the discharge opening portion (35) has a clearance between the heat transfer tubes (22a), larger than that of the remaining part (36b).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger that exchanges heat between combustion gas and a liquid flowing in a heat transfer tube.

A heat source machine (combustion device) that burns city gas or kerosene as fuel includes a primary heat exchanger for recovering combustion gas sensible heat and a secondary heat exchanger for recovering latent heat.
The secondary heat exchanger includes a substantially rectangular parallelepiped case and a heat transfer tube unit disposed inside the case, and an introduction opening for introducing combustion gas is formed on one end of the case. A discharge opening through which combustion gas is discharged is formed on the other end side of the case, and the heat transfer tube unit is formed by winding a plurality of heat transfer tubes in a plurality of stages in an elliptical shape or a rectangular shape in plan view. Some have adopted a heat exchanger (see Patent Document 1).

  In the heat exchanger of Patent Document 1, an introduction opening for introducing combustion gas is formed in the short side plate on one end side of the case, and a plurality of heat transfer tubes are provided outside the short side plate on the other end side of the case. A header portion to which the end portion is connected is provided, a discharge opening for discharging combustion gas is formed on the front side plate of the case, and in the middle portion of the first half portion and the second half portion of the multi-stage heat transfer tube, Spacers for partitioning the heat transfer tubes adjacent in the vertical direction are provided, and the flow of the combustion gas is guided by these two spacers so that the combustion gas flows through the entire heat transfer tubes in a plurality of stages.

  An example of a conventional heat exchanger will be described. As shown in FIG. 12, in this heat exchanger 100, the combustion gas introduced from the introduction opening 103 formed in the left end portion of the bottom plate 102 of the case 101 passes between the plurality of stages of heat transfer tubes 104. Flows upward from a large discharge opening 106 formed in the right side portion of the top plate 105 of the case 101, flows through a passage between the top plate 105 and the upper cover plate (not shown), and from the upper discharge port. It is configured to discharge outward.

  A spacer 107 is arranged in the left-right direction on the left end side portion of the multi-stage heat transfer tubes 104, and at the position corresponding to the rear portion of the left end portion of the discharge opening 106, the rear portions of the multi-stage heat transfer tubes 104 are arranged in the front-rear direction. An orientation spacer 108 is provided. As indicated by the arrows, among the combustion gases introduced from the introduction opening 103, the combustion gas flowing to the front of the plurality of stages of heat transfer tubes 104 flows straight to the right and flows upward from the discharge opening 106. Among the combustion gases, the combustion gas flowing toward the rear portion of the plurality of stages of the heat transfer tubes 104 flows toward the spacer 108, is guided forward by the spacer 108, flows forward, and flows upward from the discharge opening 106.

JP 2014-202402 A

  In the heat exchanger shown in FIG. 12, since the combustion gas is guided by the spacer and flows forward, the combustion gas hardly flows from the spacer 108 to the hatched area 109 shown on the right side of the spacer 108. Moreover, the right end opening end of the discharge opening 106 is located in the vicinity of the right side plate 110 of the case 101, and the upper surface of the right end side portion of the heat transfer tube 104 is opened by the discharge opening 106 and covered with the top plate 105. Therefore, the combustion gas does not flow toward the hatched area 109 but flows upward from the discharge opening 106. Therefore, a part of the heat transfer tube is not effectively used, and it is difficult to sufficiently increase the heat transfer efficiency.

  An object of the present invention is to provide a heat exchanger that enhances heat transfer efficiency by allowing combustion gas to flow through the entire heat transfer tube.

  The heat exchanger according to claim 1 includes a substantially rectangular parallelepiped case and a heat transfer tube unit disposed inside the case, and an introduction opening for introducing a combustion gas is provided at one end of the bottom plate of the case. In the heat exchanger in which a discharge opening for exhausting combustion gas is formed on the other end side of the top plate of the case, the heat transfer tube unit has a plurality of heat transfer tubes in an oval shape or a rectangular shape in plan view. Are formed in a plurality of stages and are provided with spacers that partially partition the heat transfer tubes adjacent in the vertical direction, and a plurality of the discharge openings are arranged from the other end of the case. And a part of the opening end portion on the other end side of the discharge opening portion is formed with a larger gap between the heat transfer tube than the remaining portion. It is characterized by being.

  According to a second aspect of the present invention, there is provided the heat exchanger according to the first aspect of the invention, wherein the spacer has a flat surface in the vicinity of the upstream side in the combustion gas flow direction with respect to the exhaust opening and the part of the opening end on the other end side. It is characterized by being arranged so as to face each other.

  According to a third aspect of the present invention, there is provided a heat exchanger according to the first or second aspect, wherein a header portion to which the end portions of the plurality of heat transfer tubes are connected is provided in the vicinity of the outside of the side plate on the other end portion side of the case. It is characterized by being.

  According to a fourth aspect of the present invention, there is provided the heat exchanger according to any one of the first to third aspects, wherein an introduction space in which no heat transfer tube exists is formed in the upper space of the introduction opening, and the heat transfer tube unit is formed from the introduction space. It is characterized by providing a partition member capable of distributing the combustion gas introduced toward the top and bottom in the vertical direction.

Since this invention has the structure as described in the column of the said problem-solving means, there exists the following effect.
According to invention of Claim 1, the said discharge opening part is opened in the position spaced apart from the other end part of the said case by the predetermined distance more than the horizontal direction width | variety of the heat exchanger tube arranged in a line, Part of the opening end on the other end side is formed with a larger gap between the heat transfer tube than the remaining part, so that the flow rate of the combustion gas flowing toward part of the opening end is increased. Since the flow of the combustion gas in the case is induced, the portion where the combustion gas does not flow is reduced, so that the heat transfer efficiency can be improved.

  According to the invention of claim 2, the spacer is opposed to the part of the opening end on the other end side in the vicinity of the upstream side in the combustion gas flow direction with respect to the discharge opening in a plan view. Therefore, the combustion gas is guided to the side opposite to the spacer by the spacer and flows to the remaining side of the opening end, and then flows to the part of the opening end on the other end side. Since the exhaust gas is discharged upward from the discharge opening, the contact time for the combustion gas to contact the heat transfer tube is increased, and the heat transfer efficiency is improved.

According to invention of Claim 3, since the header part to which the edge part of these heat exchanger tubes is connected is provided in the outside vicinity part of the other end part side plate of the case, the upper surface of a heat exchanger tube Therefore, a gap between the part of the opening end and the heat transfer tube is easily formed larger than a gap between the remaining part of the opening end and the heat transfer tube.

  According to the invention of claim 4, an introduction space in which no heat transfer tube exists is formed in the upper space of the introduction opening, and combustion gas introduced from the introduction space toward the heat transfer tube unit can be distributed in the vertical direction. Since the partition member is provided, the flow rate of the combustion gas flowing to the lower half side of the heat transfer tube unit can be increased, and the heat transfer efficiency can be increased.

It is a front view which shows the internal apparatus of the combustion apparatus which concerns on the Example of this invention. It is a perspective view of a heat exchanger. It is a perspective view of the heat exchanger of the state which removed the top plate. It is a perspective view of a heat exchanger tube unit. It is a top view of the heat exchanger of the state which notched the left half part of the top plate. It is a front view of the heat exchanger of the state which removed the front side board. It is a right view of the heat exchanger of the state which removed the right side board. It is a left view of the heat exchanger of the state which removed the left side plate. It is a disassembled perspective view of a spacer and a set metal fitting. FIG. 5 is a sectional view taken along line XX in FIG. 4. It is a front view of the state which removed the front side board of the heat exchanger of Example 2. FIG. It is a figure equivalent to FIG. 5 of the heat exchanger which concerns on a prior art.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the combustion apparatus 1 will be described with reference to FIG.
The combustion apparatus 1 is a hot water supply apparatus that heats clean water using liquid fuel (kerosene) as fuel and supplies hot water to a currant or a bath.

  The combustion apparatus 1 includes a burner mounting portion 3 disposed at a middle stage in the outer case 2, a combustion case 4 disposed below the burner mounting portion 3, and a lower side of the combustion case 4. The connected primary heat exchanger 5, an exhaust collecting portion 6 that collects combustion gas discharged downward from the primary heat exchanger 5, and a silencing function that extends upward from the left end of the exhaust collecting portion 6. An exhaust passage 7, a secondary heat exchanger 20 disposed near the top of the outer case 2, a neutralizer 8 for treating drainage flowing down from the bottom of the secondary heat exchanger 5 with a neutralizing agent, An exhaust discharge cylinder 9 provided at the left end of the top surface of the top of the outer case 2, an intake cylinder 10 disposed on the right side of the exhaust discharge cylinder 9, a blower fan (not shown), and a water supply system A circulation pump 12 connected to pressurize the clean water and pump it to the secondary heat exchanger 20 and the primary heat exchanger 5; And a section 13 or the like.

  The burner mounting portion 3 is provided with a fuel spray nozzle and a burner, and the burner is a reverse combustion type burner with the flame hole directed downward. Downward flames generated by a plurality of burners are introduced into the combustion case 4, and the combustion gas introduced from the combustion case 4 into the primary heat exchanger 5 uses hot water flowing through the tubes of the primary heat exchanger 5. Heat. Thereafter, the combustion gas is introduced from the exhaust collecting portion 6 through the combustion gas passage 7 to the left end portion of the secondary heat exchanger 20 and flows in the heat transfer tube 22 a of the heat transfer tube unit 22 of the secondary heat exchanger 20. After the water is heated, it is discharged from the exhaust discharge tube 9. The hot water heated by the secondary heat exchanger 20 is supplied to the fin-and-tube primary heat exchanger 5, heated by the primary heat exchanger 5, and then supplied to the hot water supply pipe.

Next, the secondary heat exchanger 20 will be described with reference to FIGS.
As shown in FIGS. 2 to 8, the secondary heat exchanger 20 (hereinafter referred to as a heat exchanger) includes a substantially rectangular parallelepiped case 21 and a heat transfer tube unit 22 accommodated in the case 21. .

  The case 21 is made of a thin steel plate, and is a partition plate that partitions the bottom half plate 21a, the front side plate 21b, the rear side plate 21c, the left side plate 21d, the right side plate 21e, and the upper right half of the introduction space 23 at the left end portion in the case 21. 24, a front side partition plate 25, a top plate 26, and the like. A cover plate (not shown) that forms a combustion gas discharge passage in cooperation with the top plate 26 is disposed near the top plate 26. The downstream end of the discharge passage is connected to the exhaust discharge cylinder 9.

  As shown in FIG. 4, the heat transfer tube unit 22 has a plurality of stages (for example, six) of stainless steel heat transfer tubes 22 a arranged in a horizontally approaching manner and wound in a rectangular shape or an oval shape in plan view. For example, the winding direction is counterclockwise in plan view. Both end portions of the plurality of heat transfer tubes 22a slightly protrude outward through the right side plate 21e, and header portions 27 and 28 are joined to the end portions of the heat transfer tubes 22a in the vicinity of the right side plate 21e. The fresh water is supplied to the header portion 27 and hot water is led out from the upper header portion 28.

  As shown in FIGS. 4, 9, and 10, a spacer 30 that partially partitions the upper and lower adjacent heat transfer tubes 22 a is located slightly to the right of the central portion in the left-right direction of the front portion 22 </ b> A of the heat transfer tube unit 22. It is attached and is constrained by a set fitting 31 attached to the spacer 30 so that the interval between the heat transfer tubes 22a becomes a predetermined interval. Similarly, a spacer 32 that partially divides the heat transfer tubes 22a adjacent to each other in the left and right direction in the central portion in the left-right direction of the rear portion 22B of the heat transfer tube unit 22 is mounted. The metal fitting 33 is constrained so that the interval between the heat transfer tubes 22a becomes a predetermined interval.

  The spacers 30 and 32 have a structure in which a stainless steel wire having a diameter of 3 and 4 mm is bent as shown in FIG. 9, and the set metal fitting 31 is transmitted to both the upper and lower ends of the stainless steel strip. Engaging portions 31a and 31b that engage with the heat tubes 22a and 22a are formed. FIG. 10 is a cross-sectional view taken along the line XX of FIG. 4 and shows a state where the spacers 30 and 32 are mounted.

  As shown in FIGS. 5 and 6, the introduction opening 33 for introducing the combustion gas is connected to the portion of the bottom plate 21 a facing the introduction space 23 in the left end portion in the case 21, to which the upper end of the combustion gas passage 7 is connected. Is formed. The introduction opening 33 is formed in an oblong shape that is elongated in the front-rear direction. In order to supply the combustion gas introduced from the introduction opening 33 toward the heat transfer tube unit 22, an introduction space 23 in which the heat transfer tube 22 a does not exist is formed in the upper space of the introduction opening 33.

  As shown in FIGS. 6 and 8, at the right end of the introduction space 23, the combustion gas introduced from the introduction space 23 toward the heat transfer tube unit 22 is distributed in the vertical direction, and the combustion gas is transferred to the heat transfer tube unit 22. A vertical partition plate 24 (corresponding to a partition member) for guiding to the lower half of the partition plate 24 is provided, and an opening passage 34 is formed below the partition plate 24. The partition plate 24 is fixed by fixing the flange 24a at the upper end to the lower surface of the top plate 26.

  When the partition plate 24 is not provided as in the conventional heat exchanger, most of the combustion gas introduced into the introduction space 23 flows up to the upper part of the introduction space 23 and from there to the upper half side of the heat transfer tube unit 22. Since it flows, the flow rate of the combustion gas flowing to the lower half side of the heat transfer tube unit 22 is reduced, and the heat transfer efficiency is lowered. Therefore, when the partition plate 24 is provided and the combustion gas is guided to the lower half side of the heat transfer tube unit 22, the combustion gas flows to the upper half side while flowing to the right in the lower half side of the heat transfer tube unit 22. For this reason, the combustion gas flows almost evenly throughout the heat transfer tube unit 22, so that the heat transfer efficiency is improved.

Next, the discharge opening 35 and the spacer 30 for discharging the combustion gas will be described.
As shown in FIGS. 5 to 7, a discharge opening 35 for discharging the combustion gas after being subjected to heat exchange upward is formed in the right end portion of the top plate 26. The discharge opening 35 is a rectangular opening having a front-rear width equivalent to the front-rear width of the heat transfer tube unit 22 and a left-right width of about 1/3 of the front-rear width.

The discharge opening 35 is opened from the right end of the case 21 at a position separated by a predetermined distance that is equal to or larger than the horizontal width (left and right width) of the heat transfer tubes arranged in a row. A gap between the front half 36a (part) of the opening end at the right end of the discharge opening 35 and the heat transfer tube 22a is larger than that of the rear half 36b (remaining part).
A portion on the right side of the top plate 26 with respect to the discharge opening 35 is formed in a horizontal flat plate portion 26a. In the heat transfer tube unit portion facing the flat plate portion 26a, the upper end surface of the rear portion 22B of the heat transfer tube unit 22 is , At a position higher than the upper end surface of the front portion 22A.

  Therefore, as shown in FIG. 7, the gap G1 between the front half 36a of the opening end and the heat transfer tube 22a is set larger than the gap G2 between the rear half 36b of the opening end and the heat transfer tube 22a. . Therefore, the flow rate of the combustion gas discharged from the gap G1 to the discharge opening 35 is higher than the flow rate of the combustion gas discharged from the gap G2 to the discharge opening 35.

  The spacer 30 attached to the front portion 22A of the heat transfer tube unit 22 is opposed to the front half portion 36a of the opening end portion in the plan view in the vicinity of the upstream side (left side) in the combustion gas flow direction with respect to the discharge opening portion 35. It is arranged in the front-rear direction.

  The spacer 32 mounted on the rear portion 22B of the heat transfer tube unit 22 is disposed in the front-rear direction at a position a predetermined distance to the left of the spacer 30. Combustion gas is guided forward by the spacer 32, and the spacer 30 moves backward by the spacer 30. It is comprised so that it may be guide | induced to the downstream (right side) of 32.

  As shown in FIG. 2, in order to make the gap between the top plate 26 and the heat transfer tube 22a as small and uniform as possible to the left of the discharge opening 35, the rear portion of the top plate 26 is stepped downward. A shallow first concave portion 37 a is formed, and a second concave portion 37 b deeper than the first concave portion 37 a stepped downward is formed in the front portion of the top plate 26.

Next, the operation and effect of the heat exchanger 20 will be described.
The combustion gas in the combustion case 4 heats hot water in the primary heat exchanger 5, and then the combustion gas flows to the exhaust passage 7 through the exhaust collecting portion 6, and the exhaust opening of the heat exchanger 20 from the upper end of the exhaust passage 7. It flows into the introduction space 23 through 33. The water flowing through the heat transfer tube 22 a of the heat transfer tube unit 22 is heated by the combustion gas flowing into the heat exchanger 20 to become hot water, and the hot water is supplied to the primary heat exchanger 5 and further in the primary heat exchanger 5. Heated to hot water.

  The combustion gas flowing into the introduction space 23 of the heat exchanger 20 flows to the lower half side of the heat transfer tube unit 22 through the opening passage 34 communicating with the lower half portion of the introduction space 23, and is shown in FIGS. 5 and 6. As shown, a part of the combustion gas flows to the upper half side of the heat transfer tube unit 22 while flowing to the right side on the lower half side of the heat transfer tube unit 22, and the combustion flows toward the upstream spacer 32. Most of the gas is guided forward by the spacer 32 and then flows to the right, and then most of the combustion gas is guided backward by the spacer 30 on the downstream side.

  Thereafter, a part of the combustion gas flows on the upper layer side of the rear portion 22B of the heat transfer tube unit 22, and most of the combustion gas flows on the lower layer and the middle layer side of the rear portion 22B of the heat transfer tube unit 22 and flows below the flat plate portion 26a. To do. The combustion gas that has flowed through the upper layer flows upward from the discharge opening 35, flows into the discharge passage between the top plate 26 and the cover plate, and is discharged from the discharge / discharge cylinder 9.

  The combustion gas that has flowed downward from the flat plate portion 26a is guided forward by the right side plate 21e, flows forward between the heat transfer tubes 22a and between the flat plate portion 26a and the heat transfer tubes 22a, and then the first half of the discharge opening 35. From the top plate 26 and the cover plate to the discharge passage, and is discharged from the discharge / discharge cylinder 9.

  Since the discharge opening 35 is opened from the right end of the case 21 at a position separated by a predetermined distance from the right and left width in the horizontal direction of the plurality of heat transfer tubes 22a, the right end of the case 21 is disposed in the heat transfer tube unit 22. Since the combustion gas that has flowed to the side is less likely to immediately flow upward from the discharge opening 35, the heat transfer efficiency is improved.

Moreover, the gap G1 between the front half 36a of the opening end at the right end of the discharge opening 35 and the heat transfer tube 22a is formed larger than the gap G2 between the rear half 36b of the opening end and the heat transfer tube 22a. The flow of combustion gas in the case 21 can be induced to increase the heat transfer efficiency so that the flow rate of the combustion gas flowing toward the front half 36a of the opening end is increased.

  The downstream spacer 30 is disposed in the vicinity of the upstream side in the combustion gas flow direction with respect to the discharge opening 35 so as to face the front half 36a of the opening end on the right end in plan view. After being guided to the side opposite to the spacer 30 by the spacer 30, the middle layer and the lower layer in the heat transfer tube unit 22 flow to the right from the discharge opening 35, flow to the front half 36 a side, and upward from the discharge opening 35. Since it is discharged, the contact time for the combustion gas to come into contact with the heat transfer tube 22a becomes longer, and the heat transfer efficiency is improved.

  Header portions 27 and 28 to which the ends of the plurality of heat transfer tubes 22a are connected are provided in the vicinity of the outside of the right side plate 21e of the case, and the heat transfer efficiency of the heat transfer tubes 22a in the vicinity of the header portions 27 and 28 is provided. Therefore, the performance of the heat exchanger is improved.

  An introduction space 23 in which the heat transfer tube 22a does not exist is formed in the upper space of the introduction opening 33, and a partition plate 24 capable of distributing combustion gas introduced from the introduction space 23 toward the heat transfer tube unit 22 in the vertical direction is provided. Since it provided, it becomes possible to increase the flow volume of the combustion gas which flows into the lower half side of the heat exchanger tube unit 22, and it becomes possible to improve heat transfer efficiency.

Next, the heat exchanger 20A according to the second embodiment will be described with reference to FIG.
Instead of the partition plate 24 attached to the introduction space 23 in the first embodiment, a partition member 24A having an L-shaped cross section that can distribute combustion gas introduced from the introduction space 23 toward the heat transfer tube unit 22 in the vertical direction. It is provided in the lower half of the introduction space 23.

  The partition member 24A includes a web 24w that is vertical and oriented in the front-rear direction, and a flange 24f that extends horizontally from the upper end of the web 24w to the right. The web 24w is disposed at a position where the introduction opening 33 is divided into left and right. The ratio of the opening area on the left side of the web 24w and the opening area on the right side of the web 24w in the introduction opening 33 is, for example, 30. : The web 24w is arranged at the dividing position where 70 is obtained.

  Therefore, about 70% of the combustion gas is introduced into the lower layer and the middle layer of the heat transfer tube unit 22, and about 30% of the combustion gas is introduced into the upper layer side of the heat transfer tube unit 22. In addition, the ratio of 30:70 is an example, and is not limited to this ratio. In view of the fact that the combustion gas also flows upward while flowing inside the heat transfer tube unit 22 to the right, the flow rate of the combustion gas introduced to the lower and middle layers of the heat transfer tube unit 22 is set as described above. To do. Thereby, the heat transfer efficiency of 20 A of heat exchangers can be improved.

Next, an example in which the above embodiment is partially changed will be described.
1) The heat exchangers 20 and 20A may have a structure in which the left and right sides are reversed so that the side with the header portions 27 and 28 is the left side and the side with the introduction opening 33 is the right side.
2) The number of heat transfer tubes and the number of stages in the heat transfer tube unit are not limited to those of the above-described embodiments.

3) The shape of the discharge opening 35 is not limited to a rectangular shape, and various shapes of discharge openings can be employed.
4) In addition, those skilled in the art can implement the present invention by adding various modifications to the embodiments without departing from the spirit of the present invention, and the present invention includes such modifications.

20, 20A Heat exchanger 21 Case 21a Bottom plate 22 Heat transfer tube unit 22a Heat transfer tube 23 Introduction space 24 Partition plate (partition member)
24A Partition member 26 Top plate 27, 28 Header part 30 Spacer 33 Introduction opening part 35 Discharge opening part 36a Front half part (part) of opening end part
36b Second half of opening end (remaining part)

Claims (4)

A case having a substantially rectangular parallelepiped shape and a heat transfer tube unit disposed inside the case, wherein an introduction opening for introducing combustion gas is formed on one end of the bottom plate of the case, and the top plate of the case In the heat exchanger in which a discharge opening for combustion gas discharge is formed on the other end side of the
The heat transfer tube unit is formed in a plurality of stages by winding a plurality of heat transfer tubes in an elliptical shape or a rectangular shape in plan view, and provided with a spacer that partially partitions the heat transfer tubes adjacent vertically.
The discharge opening is opened at a position spaced apart from the other end of the case by a predetermined distance equal to or greater than the horizontal width of the heat transfer tubes arranged side by side, and the open end on the other end side of the discharge opening A part of the heat exchanger is characterized in that a gap between the heat transfer tube is formed larger than the remaining part.   The spacer is arranged in the vicinity of the upstream side in the combustion gas flow direction with respect to the discharge opening so as to face the part of the opening end on the other end side in plan view. The heat exchanger according to claim 1.   3. The heat exchange according to claim 1, wherein a header portion to which ends of the plurality of heat transfer tubes are connected is provided in an outer vicinity of the side plate on the other end portion side of the case. vessel. An introduction space in which no heat transfer tube exists is formed in the upper space of the introduction opening,
The heat exchanger according to any one of claims 1 to 3, further comprising a partition member capable of distributing combustion gas introduced from the introduction space toward the heat transfer tube unit in a vertical direction.