JP6173797B2 - Heat exchanger and water heater - Google Patents

Description

  The present invention relates to a heat exchanger and a water heater.

  2. Description of the Related Art Conventionally, a heat exchanger including a heat transfer section having a structure in which a plurality of heat transfer tubes arranged in parallel is spirally wound has been proposed (see, for example, Patent Document 1). In the case of the heat exchanger described in Patent Document 1, the plurality of heat transfer tubes have a virtual axis extending in the vertical direction, and each heat transfer tube draws a coaxial spiral around the axis. .

  Such a helical heat transfer tube is accommodated in the casing, and heat exchange is performed between the combustion exhaust gas flowing in the casing and the heated fluid flowing in the heat transfer tube. The flow direction of the combustion exhaust in the casing is a direction that intersects a virtual axis that becomes the center of the spiral formed by the plurality of heat transfer tubes. Therefore, each heat transfer tube is in the middle from one end to the other end, an area on the upstream side of the combustion exhaust flow path (hereinafter also referred to as an upstream area) and an area on the downstream side of the flow path (hereinafter referred to as the upstream path). , Which is also referred to as a downstream region).

JP 2011-43281 A

  By the way, in the helical heat transfer tube as described above, a portion crossing the upstream region (hereinafter also referred to as an upstream heat transfer portion) and a portion crossing the downstream region (hereinafter also referred to as a downstream heat transfer portion). Then, the height position of the heat transfer tube is shifted in the vertical direction by an amount corresponding to the half pitch of the spiral.

  Therefore, when such a helical heat transfer tube is housed in a general rectangular parallelepiped casing, a space where no heat transfer tube exists is formed above either the upstream heat transfer unit or the downstream heat transfer unit. Will be. In such a space, since the combustion exhaust passes without contacting the heat transfer tube, the combustion exhaust may be discharged outside the casing without sufficiently depriving the heat of the combustion exhaust. .

  In particular, since high-temperature combustion exhaust tends to flow upward, combustion exhaust that has passed near the upper part of the upstream heat transfer section when the above-described space is formed above the downstream heat transfer section. Becomes easy to flow into a space where there is no heat transfer tube, which causes a decrease in thermal efficiency.

  Such a problem is not limited to the case where the heat transfer tube is formed in a spiral shape, and the downstream heat transfer section is located lower than the upstream heat transfer section, and is located above the downstream heat transfer section. If space exists, it can be a problem that can occur as well.

  The present invention has been made to solve the above-described problems, and one of its purposes is to provide a heat transfer tube on the downstream side in the flow direction at a position lower than the heat transfer tube on the upstream side in the flow direction of combustion exhaust. Is to provide a heat exchanger capable of efficiently exchanging heat on the downstream side, and a water heater provided with such a heat exchanger.

Hereinafter, the configuration employed in the present invention will be described.
The heat exchanger of the present invention forms an internal space, and among the locations on both sides of the internal space, an inlet for introducing combustion exhaust into the internal space is formed at one location, and the other Is formed of a casing formed with a discharge port for discharging combustion exhaust from the internal space, and a heat transfer pipe disposed in the internal space of the casing, and in the internal space of the casing from the inlet side. A heat transfer portion that transfers heat of the combustion exhaust flowing to the discharge port side to a heated fluid flowing inside the heat transfer tube, and the heat transfer portion is provided in the internal space of the casing from the inlet port side. With respect to the flow direction of the combustion exhaust flowing to the exhaust port side, an upstream heat transfer section disposed at a position upstream of the combustion exhaust flow direction and a position downstream of the combustion exhaust flow direction Arranged A downstream heat transfer section, the upstream heat transfer section has a first portion provided at a position higher than the downstream heat transfer section in the vertical direction, and the downstream heat transfer section is A second portion provided at a position lower than the first portion, and the casing has a ceiling portion covering an upper portion of a range extending from the upstream heat transfer portion to the downstream heat transfer portion, and the ceiling portion A first region provided at a position above the first portion, and a first region provided continuously from the first region to the upper portion of the second portion. A second region and a third region provided at a position above the second portion are formed continuously from the second region, and the first region is formed at a position higher than the third region. And the second region includes the first region side to the third region side. Headed inclined to be falling gradient is applied, there is a structure for guiding the combustion exhaust along the inclined obliquely downward.

  According to the heat exchanger comprised in this way, the 3rd area | region is provided in the position lower than a 1st area | region in a ceiling part. Therefore, the capacity of the space formed above the first part and the second part, even though the second part of the downstream heat transfer part is provided at a position lower than the first part of the upstream heat transfer part. And the contact efficiency between the combustion exhaust and the heat transfer tube can be increased. In addition, the high-temperature combustion exhaust gas that has passed near the upper part of the upstream heat transfer section flows obliquely downward along the second region of the ceiling part, despite the tendency to flow in the upward direction, It reaches the downstream heat transfer section. Therefore, the contact efficiency between the combustion exhaust and the heat transfer tube can be increased as compared with the case where the combustion exhaust that has passed through the vicinity of the upper portion of the upstream heat transfer section flows further in the upward direction. Therefore, the contact efficiency between the combustion exhaust and the heat transfer tube becomes extremely high, and the combustion exhaust can be prevented from passing outside the casing without contacting the heat transfer tube, so that the thermal efficiency can be increased.

  In the heat exchanger of the present invention, a plurality of the heat transfer tubes are arranged in the second part at intervals in the flow direction of the combustion exhaust, and the flow direction of the combustion exhaust among the heat transfer tubes. The one or more heat transfer tubes arranged on the upstream side are arranged below the second region, and more downstream of the one or more heat transfer tubes arranged below the second region in the flow direction of the combustion exhaust gas. It is preferable that the one or more arranged heat transfer tubes are arranged below the third region.

  According to the heat exchanger configured as described above, one or more heat transfer tubes among the plurality of heat transfer tubes disposed in the second portion of the downstream heat transfer section are disposed below the second region. In addition, one or more heat transfer tubes further downstream in the flow direction of the combustion exhaust are disposed below the third region. Therefore, the combustion exhaust gas that flows obliquely downward along the second region flows toward the heat transfer tube included in the second portion of the downstream heat transfer section, so that the thermal efficiency in the downstream heat transfer section can be improved. it can.

  In the heat exchanger according to the present invention, the ceiling portion is configured by a part formed by forming a concave portion recessed below the four sides of the metal plate with respect to the quadrilateral metal plate, and at least the second region and the It is preferable that the third region is constituted by the lower surface of the concave portion.

  According to the heat exchanger configured as described above, since the above-described recesses are formed in the quadrilateral metal plate, the intended second region and third region are provided. If it is a simple recessed part, it can form by the drawing process with respect to a metal plate. Therefore, the number of parts can be reduced as compared with a structure in which a plurality of separate parts are joined, and a problem that combustion exhaust gas leaks from the joined part can be prevented.

  In the heat exchanger according to the present invention, a plurality of the heat transfer tubes are arranged at intervals in the vertical direction in the heat transfer unit, and between the heat transfer tubes in positions adjacent to each other in the vertical direction, It is preferable that a spacer for suppressing the interval between the heat transfer tubes from being excessively narrowed is provided, and one or more through holes penetrating in the vertical direction are formed in the spacer.

  According to the heat exchanger comprised in this way, the space | interval of the heat exchanger tube in the position adjacent in an up-down direction can be maintained appropriately by a spacer. Moreover, since the through hole as described above is formed in the spacer, the combustion exhaust gas flows in the vertical direction through the through hole. Therefore, it is possible to suppress the flow of combustion exhaust gas from being restricted by the spacer.

  In the heat exchanger according to the present invention, in the heat transfer section, the heat transfer pipes constituting the upstream heat transfer section and the downstream heat transfer section respectively correspond to both the flow direction and the vertical direction of the combustion exhaust gas. It extends in the crossing direction, and one end side of both ends of the extending direction communicates the heat transfer tube on the upstream heat transfer unit side and the heat transfer tube on the downstream heat transfer unit side. A first series communicating portion constituted by a heat tube is provided, and the other end side is constituted by a heat transfer tube that communicates the heat transfer tube on the upstream heat transfer portion side and the heat transfer tube on the downstream heat transfer portion side. By providing the second communication portion, the upstream heat transfer portion returns to the upstream heat transfer portion via the first communication portion, the downstream heat transfer portion, and the second communication portion. A spiral pipe is formed in which one round of pipe is repeated spirally over multiple rounds. In addition, at a position where the plurality of heat transfer tubes constituting each of the first communication portion and the second communication portion are sandwiched from both upper and lower sides, there is a suppressing portion that suppresses an excessive expansion of the interval between the plurality of heat transfer tubes. It is preferable that one or more through holes penetrating in the vertical direction are formed in the holding portion.

  According to the heat exchanger configured as described above, since the plurality of heat transfer tubes are sandwiched from above and below by the above-described restraining portion, the interval between the plurality of heat transfer tubes can be properly maintained. . Moreover, since the through hole as described above is formed in the holding portion, the combustion exhaust gas flows in the vertical direction through the through hole. Therefore, it is possible to suppress the distribution of the combustion exhaust gas from being restricted by the suppressing portion.

  In the heat exchanger according to the present invention, in the internal space of the casing, the horizontal direction is at a position between the downstream heat transfer section and the outlet, and the vertical direction is lower than the outlet. Is preferably provided with a vent through which the combustion exhaust flowing from the downstream heat transfer section to the exhaust port passes.

  According to the heat exchanger configured as described above, the combustion exhaust gas that has passed through the upstream heat transfer section and the downstream heat transfer section flows to the discharge port after passing through the vent hole located at a position lower than the discharge port. . For this reason, in the region higher than the vent in the casing, the combustion exhaust gas that tends to rise flows in, so that the high-temperature combustion exhaust gas stays for a long time. Therefore, the combustion exhaust and the heat transfer tube can be brought into contact with each other for a longer period of time than the case where the combustion exhaust flows straight toward the discharge port located above without passing through such a vent. , Thermal efficiency can be improved.

The water heater of the present invention includes any of the heat exchangers described above.
According to the water heater configured as described above, since the heat exchanger of the present invention is provided, the operation and effect as described for the heat exchanger of the present invention can be achieved, and a water heater having high thermal efficiency can be obtained. it can.

The front view which fractured | ruptured a part of water heater and showed the internal structure. (A) is the perspective view which looked at the sub heat exchanger from the front right upper part, (b) is the top view which shows a sub heat exchanger. (A) is a perspective view which shows the arrangement position of the heat-transfer part in a subheat exchanger, (b) is a top view which shows the arrangement position of the heat-transfer part in a subheat exchanger. (A) is the perspective view which looked at the heat-transfer part from the upper left front, (b) is a top view of a heat-transfer part, (c) is a front view of a heat-transfer part. (A) is a perspective view of a restraining part, (b) is a left side view of the restraining part, (c) is a plan view of the restraining part, and (d) is a front view of the restraining part. Sectional drawing in the cut surface shown by the AA line in FIG.4 (c). (A) is sectional drawing of the upper part of a subheat exchanger in the cut surface shown by the BB line in Fig.3 (a) and FIG.3 (b), (b) is FIG.3 (a) and FIG.3 (b). Sectional drawing of the auxiliary | assistant heat exchanger upper part in the cut surface shown by the CC line in FIG. 3, (c) is the auxiliary | assistant heat exchanger in the cut surface shown by the DD line in Fig.3 (a) and FIG.3 (b). Sectional drawing of upper part, (d) is sectional drawing of the sub-heat exchanger upper part in the cut surface shown by the EE line | wire in FIG. 3 (a) and FIG.3 (b). Explanatory drawing which showed notionally the flow direction of the combustion exhaust in the inside of a subheat exchanger.

Next, embodiments of the present invention will be described with specific examples.
What will be described below is an example in which the configuration of the present invention is adopted in a latent heat recovery type water heater and a sub-heat exchanger provided in the water heater. In the following description, the structure of the water heater or the auxiliary heat exchanger will be described using the front, rear, left, right, top and bottom directions shown in the drawing. However, these directions are only directions that are defined for the sake of brevity in order to briefly explain the relative positional relationship of each part of the water heater, and which side of the water heater or auxiliary heat exchanger should be regarded as the front side. Is optional.

  The water heater 1 illustrated in FIG. 1 includes a sub heat exchanger 3 for recovering latent heat at the top. The high-temperature combustion exhaust gas generated by burning fuel (gas) in the water heater 1 is first passed through the main heat exchanger, and then is passed to the auxiliary heat exchanger 3. Thereby, in the main heat exchanger, sensible heat is mainly recovered from the combustion exhaust, and in the auxiliary heat exchanger 3, latent heat is mainly recovered from the combustion exhaust.

  The sub heat exchanger 3 includes a metal casing 5. On the right side surface of the casing 5, a first joint portion 7A and a second joint portion 7B are provided. A water inlet pipe 9A is connected to the first joint portion 7A, and a water outlet pipe 9B is connected to the second joint portion 7B. As shown in FIG. 2A, the first joint portion 7A is provided on the right side surface of the casing 5 at a position lower than the second joint portion 7B and forward of the second joint portion 7B. Yes.

  As shown in FIG. 2 (b), an inlet 11 for introducing combustion exhaust into the casing 5 is formed on the rear side (back side) of the casing 5. On the other hand, a discharge port 13 for discharging combustion exhaust from the inside of the casing 5 to the outside is formed on the front side (front side) of the casing 5. As shown in FIG. 1, an exhaust hood 15 is attached at a position covering the discharge port 13.

  The combustion exhaust gas introduced into the casing 5 from the inlet 11 side flows through the internal space of the casing 5 from the inlet 11 side to the outlet 13 side. That is, in the casing 5, the flow direction of the combustion exhaust is a direction from the back side to the front side of the auxiliary heat exchanger 3.

  As shown in FIGS. 3A and 3B, the heat transfer section 17 is accommodated in the internal space of the casing 5. The heat transfer unit 17 includes a plurality (10 in this embodiment) of heat transfer tubes 19. As shown in FIGS. 4 (a), 4 (b), and 4 (c), these heat transfer tubes 19 are centered on a virtual axis extending in the vertical direction, and are transferred around the axis. The heat tube 19 has a shape drawing a coaxial spiral.

  More specifically, each heat transfer tube 19 includes a rear portion 19A extending from the upper right to the lower left on the upstream side in the flow direction of the combustion exhaust, and a front side portion 19B extending from the upper left to the lower right on the downstream side in the flow direction of the combustion exhaust. Have Further, it has a left side portion 19C that communicates between the left ends of the rear side portion 19A and the front side portion 19B, and a right side portion 19D that communicates between the right ends of the rear side portion 19A and the front side portion 19B.

  From the lower end side of each heat transfer tube 19, these are the front part 19B, the left part 19C, the rear part 19A, the right part 19D, the front part 19B, the left part 19C, the rear part 19A, the right part 19D, the front part 19B, The left portion 19C and the rear portion 19A are arranged in this order. Thereby, a spiral pipe line is formed from the lower end of each heat transfer tube 19 to the upper end while turning in the clockwise direction in the plan view shown in FIG. 4B. The lower end of each heat transfer tube 19 communicates with the first joint portion 7A, and the upper end of each heat transfer tube 19 communicates with the second joint portion 7B.

  A plurality of rear side portions 19A of each heat transfer tube 19 are arranged upstream of the front side portion 19B in the flow direction of the combustion exhaust. Hereinafter, a portion constituted by the plurality of rear side portions 19A is referred to as an upstream heat transfer portion 17A. Moreover, the several front side part 19B which each heat exchanger tube 19 has exists in the state arrange | positioned rather than the rear side part 19A in the distribution direction downstream of combustion exhaust gas. Hereinafter, the part comprised by these several front side parts 19B is called the downstream heat-transfer part 17B. Further, a portion formed by the plurality of left side portions 19C included in each heat transfer tube 19 is referred to as a first series portion 17C, and a portion configured by a plurality of right side portions 19D included in each heat transfer tube 19 Is referred to as a second communication portion 17D. The upstream heat transfer section 17A, the downstream heat transfer section 17B, the first communication section 17C, and the second communication section 17D are generally in a range as indicated by a two-dot chain line in FIG.

  Since the plurality of heat transfer tubes 19 are formed in a coaxial spiral shape, the rear side portion 19A constituting the upstream heat transfer portion 17A and the front side portion 19B constituting the downstream heat transfer portion 17B have a spiral 1 There is a deviation in the height position by a distance corresponding to / 2 pitch. Therefore, the upstream heat transfer section 17A has the first portion 21 provided at a position higher than the downstream heat transfer section 17B in the vertical direction, and the downstream heat transfer section 17B is at a position lower than the first portion 21. It has a second part 22 provided. That is, on the upper surface side of the heat transfer section 17, a part of the upstream heat transfer section 17 </ b> A is located higher than the downstream heat transfer section 17 </ b> B, and is on the front side of the first portion 21 and on the upper side of the second portion 22. The position is an area where the heat transfer tubes 19 are not arranged. The first portion 21 is generally in a range as indicated by a two-dot chain line in FIG. 4C, and the second portion 22 is in a range below the range.

  In the first series portion 17C, a holding portion 23A is disposed at a position sandwiching the plurality of left side portions 19C from both the upper and lower sides. Further, in the second communication portion 17D, a holding portion 23B is disposed at a position where the plurality of right side portions 19D are sandwiched from both the upper and lower sides.

  As shown in FIGS. 5 (a) to 5 (d), the holding portion 23 </ b> A is formed in a substantially U shape in plan view and surrounds the side of the heat transfer tube 19 from three sides, and both upper and lower ends of the side wall 24. A main holding plate 25 and a sub holding plate 26 are provided that extend horizontally from the respective sides and sandwich the heat transfer tube 19 from above and below. The side wall 24 is formed with a through-hole 27 having a circular shape in side view and penetrating in the horizontal direction, and an opening 28 having a rectangular shape in side view penetrating in the horizontal direction. Through-holes 29 are formed. Although the holding portion 23B is smaller in size in the height direction than the holding portion 23A, it is the same as the holding portion 23A in that the shape in plan view and the through holes 27 and 29 and the opening 28 are provided, and the holding portion is also functional. It is equivalent to 23A.

  These holding portions 23A and 23B sandwich the plurality of heat transfer tubes 19 from both the upper and lower sides by the main holding plate 25 and the sub holding plate 26, so that the interval between the plurality of heat transfer tubes 19 is excessively expanded in the vertical direction. Suppress. Further, the plurality of heat transfer tubes 19 are sandwiched from both the left and right sides by the substantially U-shaped side wall 24 in plan view, thereby preventing the plurality of heat transfer tubes 19 from being displaced in the front-rear direction.

  Furthermore, as shown in FIG. 6, a spacer 31 is disposed between the heat transfer tubes 19 that are adjacent to each other in the vertical direction in the first communication portion 17 </ b> C and the second communication portion 17 </ b> D. The spacer 31 is interposed between the heat transfer tubes 19 and 19 located adjacent to each other in the vertical direction, and suppresses an excessively narrow interval between the heat transfer tubes 19 and 19.

  The spacer 31 is provided with a plurality of convex portions 32 projecting upward in association with positions between the heat transfer tubes 19 and 19 located adjacent to each other in the radial direction of the spiral. These convex portions 32 enter between the heat transfer tubes 19 and 19 located adjacent to each other in the radial direction of the spiral, thereby suppressing the interval between the heat transfer tubes 19 and 19 from being excessively narrowed. Yes. A through hole 33 penetrating in the vertical direction is formed at the center position of the plurality of convex portions 32 of the spacer 31.

  As shown in FIGS. 2A and 2B, the upper surface portion 5 </ b> A of the casing 5 is formed with a recess 35 that is recessed below the four sides of the metal plate with respect to a quadrilateral (rectangular) metal plate. It is structured. As shown in FIGS. 7A to 7D, the upper surface portion 5A constitutes a ceiling portion 37 that covers the upper portion of the range from the upstream heat transfer portion 17A to the downstream heat transfer portion 17B.

  On the lower surface of the ceiling portion 37, a first region 41, a second region 42, and a third region 43 are formed at positions indicated by thick broken lines in FIG. Among these regions, the first region 41 is provided at a position above the first portion 21. The second area 42 is provided in a range extending continuously from the first area 41 and above the second portion 22. The third region 43 is provided at a position above the second portion 22 continuously from the second region 42.

  As shown in FIGS. 7A to 7D, the first region 41 is formed at a position higher than the third region 43. In addition, the first region 41 is provided with a slope that has a downward slope from right to left, while the third region 43 is provided with a slope that has a downward slope from left to right. Thereby, both the 1st area | region 41 and the 3rd area | region 43 incline along the inclination of the left-right direction of the heat exchanger tube 19, and suppress that an excessive space | gap arises between the heat exchanger tube 19 and the ceiling part 37. ing. Accordingly, the second portion 22 of the downstream heat transfer portion 17B is provided at a position lower than the first portion 21 of the upstream heat transfer portion 17A, but above the first portion 21 and the second portion 22. The capacity of the formed space can be reduced, and the contact efficiency between the combustion exhaust and the heat transfer tube 19 can be increased.

  Further, the second area 42 is provided with an inclination that becomes a downward gradient from the first area 41 side toward the third area 43 side. Since the first region 41 and the third region 43 are provided with the inclination as described above, the height positions of the first region 41 and the third region 43 have a greater height difference toward the right side. According to this height difference, the length of the inclined direction of the inclined surface in the second region 42 is also increased toward the right side. Further, the lower end side of the inclined surface formed by the second region 42 reaches above the heat transfer tube 19 constituting the second portion 22.

  As shown in FIG. 8, in the inner space of the casing 5, a position between the downstream heat transfer section 17 </ b> B and the outlet 13 in the horizontal direction and a position lower than the outlet 13 in the vertical direction are as shown in FIG. 8. An air vent 45 through which combustion exhaust gas flowing from the downstream heat transfer section 17B to the exhaust port 13 passes is provided.

  In the water heater 1 configured as described above, water is supplied to each heat transfer pipe 19 from the water inlet pipe 9A, and the water flows into each heat transfer pipe 19 via the first joint portion 7A. Further, the combustion exhaust from which the sensible heat is mainly recovered in the main heat exchanger flows into the internal space of the casing 5 through the introduction port 11.

  The combustion exhaust gas introduced into the internal space of the casing 5 has already been deprived of sensible heat in the main heat exchanger, resulting in a decrease in temperature and a corresponding increase in relative humidity. Therefore, when the combustion exhaust and the heat transfer tube 19 come into contact with each other, water vapor in the combustion exhaust is condensed to generate drain (condensed water), and latent heat is mainly recovered from the combustion exhaust. Thereby, the water flowing in each heat transfer tube 19 is heated, and the heated water flows out to the water discharge tube 9B through the second joint portion 7B. In addition, the water which distribute | circulates the drain pipe 9B is further sent to the main heat exchanger, and is heated.

  In the internal space of the casing 5, the combustion exhaust gas flows from the inlet 11 side to the outlet 13 side with a slight upward tendency as illustrated in FIG. However, the combustion exhaust gas that has passed through the vicinity of the upper portion of the upstream heat transfer section 17A flows obliquely downward along the second region 42 of the ceiling section 37, although it tends to flow in the upward direction. And reaches the downstream heat transfer section 17B.

  For this reason, the combustion exhaust flows toward the downstream heat transfer section 17B as compared with the case where the combustion exhaust that has passed near the upper portion of the upstream heat transfer section 17A flows further in the upward direction. Contact efficiency can be increased. Therefore, the contact efficiency between the combustion exhaust and the heat transfer tube 19 becomes extremely high, and the combustion exhaust can be prevented from passing outside the casing 5 without contacting the heat transfer tube 19, so that the thermal efficiency can be increased.

  In the case of the present embodiment, a floor portion 51 is provided in the casing 5 at a position opposite to the ceiling portion 37 across the heat transfer portion 17 as shown in FIG. According to the shape of the lower surface side of the heat transfer section 17, the floor section 51 has a portion below the upstream heat transfer section 17 </ b> A that rises above a portion below the downstream heat transfer section 17 </ b> B. Yes.

  Thereby, even under the heat transfer section 17, the occurrence of an excessive gap between the heat transfer tube 19 and the floor section 51 is suppressed. Therefore, the capacity of the space formed below the heat transfer unit 17 can be reduced, and the contact efficiency between the combustion exhaust and the heat transfer tube 19 can be increased.

  In addition, in the auxiliary heat exchanger 3, the intended second region 42 and third region 43 are provided by forming the concave portion 35 as described above. It can be formed by drawing the plate. Therefore, unlike the structure in which a plurality of separate parts are joined to provide the equivalent second region 42 and third region 43, the number of parts can be reduced, and the combustion exhaust leaks from the joined part. It is possible to prevent problems such as

  Further, in the auxiliary heat exchanger 3, the combustion exhaust gas that has passed through the upstream heat transfer unit 17 </ b> A and the downstream heat transfer unit 17 </ b> B passes through the vent 45 located at a position lower than the discharge port 13 and then to the discharge port 13. And flow. Therefore, in a region higher than the vent hole 45 in the casing 5, the combustion exhaust gas that is rising tends to flow, so that the high-temperature combustion exhaust gas stays for a long time.

  Accordingly, the combustion exhaust and the heat transfer tube 19 are brought into contact with each other for a longer time than the case where the combustion exhaust flows straight toward the discharge port 13 located above without passing through the vent 45. And thermal efficiency can be improved.

  Further, in the sub heat exchanger 3, the heat transfer tube 19 is provided with the through holes 27, 29, 33 and the opening 28 in the holding portions 23 </ b> A, 23 </ b> B and the spacer 31, so these through holes 27, 29 are provided. , 33 and the opening 28 circulate the combustion exhaust gas. Therefore, compared with the case where such through-holes 27, 29, and 33 and the opening 28 are not provided, the combustion exhaust gas flows through the interior space of the casing 5 to improve the thermal efficiency.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said specific one Embodiment, In addition, it can implement with a various form.
For example, in the above-described embodiment, as an example of the heat transfer section 17, a plurality of heat transfer tubes 19 are formed in a spiral shape and those spirals are arranged coaxially. The specific three-dimensional structure is not limited to the above example.

  As another example, for example, a heat transfer tube that is not spiral may be used, or a heat transfer tube that is spiral but not coaxially arranged may be used. In the case of the above embodiment, since the heat transfer tube 19 has a spiral shape, the water flowing through the heat transfer tube 19 alternately passes through the upstream heat transfer unit 17A and the downstream heat transfer unit 17B. Depending on the shape, the upstream heat transfer section 17A and the downstream heat transfer section 17B may not pass alternately.

  Moreover, although the example provided with the suppression parts 23A and 23B and the spacer 31 was shown in the said embodiment, it is arbitrary whether these suppression parts 23A and 23B and the spacer 31 are provided.

  DESCRIPTION OF SYMBOLS 1 ... Hot water heater, 3 ... Sub heat exchanger, 5 ... Casing, 7A ... 1st joint part, 7B ... 2nd joint part, 9A ... Inlet pipe, 9B ... Outlet pipe, 11 ... Inlet port, 13 ... Discharge port, DESCRIPTION OF SYMBOLS 15 ... Exhaust hood, 17 ... Heat transfer part, 17A ... Upstream heat transfer part, 17B ... Downstream heat transfer part, 17C ... First communication part, 17D ... Second communication part, 19 ... Heat transfer pipe, 19A ... Rear Side part, 19B ... front part, 19C ... left part, 19D ... right part, 21 ... first part, 22 ... second part, 23A, 23B ... restraining part, 24 ... side wall, 25 ... main restraining plate, 26 ... sub restraining Plates 27, 29 ... through holes, 28 ... openings, 31 ... spacers, 32 ... convex portions, 33 ... through holes, 35 ... concave portions, 37 ... ceiling portions, 41 ... first region, 42 ... second region, 43 ... 3rd area | region, 45 ... vent, 51 ... floor part.

Claims (7)

An internal space is formed, and an inlet for introducing combustion exhaust into the internal space is formed in one of the locations on both sides of the internal space, and the other location from the internal space. A casing having a discharge port for discharging combustion exhaust;
A heated fluid that is constituted by a heat transfer tube disposed in the internal space of the casing, and that heats the combustion exhaust gas flowing from the inlet side to the discharge port side in the internal space of the casing. And a heat transfer section that transmits to
The heat transfer portion is disposed upstream of the distribution direction of the combustion exhaust flowing in the internal space of the casing from the introduction port side to the discharge port side. A heat transfer section, and a downstream heat transfer section disposed at a position on the downstream side in the flow direction of the combustion exhaust,
The upstream heat transfer section has a first portion provided at a position higher than the downstream heat transfer section in the vertical direction, and the downstream heat transfer section is provided at a position lower than the first portion. Having a second part,
The casing has a ceiling part that covers the upper part of the range from the upstream heat transfer part to the downstream heat transfer part,
The ceiling portion is provided with a recess recessed downward.
A lower surface of the concave portion is provided with a first region provided at a position above the first portion and a range continuously from the first region to the upper portion of the second portion. A second region, and a third region provided at a position above the second part continuously from the second region,
The first region is formed at a position higher than the third region by forming a portion constituting the lower surface of the recess in the third region so as to be recessed below the first region. The second region is provided with an inclination that is downwardly inclined from the first region side toward the third region side, and the combustion exhaust gas is guided obliquely downward along the inclination. Heat exchanger. In the second part, a plurality of the heat transfer tubes are arranged at intervals in the flow direction of the combustion exhaust gas, and one or more of the heat transfer tubes arranged on the upstream side in the flow direction of the combustion exhaust gas The heat transfer tube is disposed below the second region, and the one or more heat transfer tubes disposed downstream of the one or more heat transfer tubes disposed below the second region in the flow direction of the combustion exhaust gas. The heat exchanger according to claim 1, wherein the heat pipe is disposed below the third region. It said ceiling portion is constituted by a part obtained by forming the recess recessed below the four sides of the metal plate relative to the quadrilateral metal plate,
The heat exchanger according to claim 1 or 2, wherein at least the second region and the third region are configured by a lower surface of the recess. In the heat transfer section, a plurality of the heat transfer tubes are arranged at intervals in the vertical direction,
Between the heat transfer tubes that are adjacent to each other in the vertical direction, a spacer that suppresses an excessively narrow interval between the heat transfer tubes is disposed,
The heat exchanger according to any one of claims 1 to 3, wherein the spacer is formed with one or more through holes penetrating in a vertical direction. In the heat transfer section, the heat transfer tubes constituting the upstream heat transfer section and the downstream heat transfer section respectively extend in a direction intersecting both the flow direction and the vertical direction of the combustion exhaust. In the both ends in the extending direction, one end side is constituted by a heat transfer tube that communicates the heat transfer tube on the upstream heat transfer portion side and the heat transfer tube on the downstream heat transfer portion side. On the other end side, a second communication portion is provided that is configured by a heat transfer tube that communicates the heat transfer tube on the upstream heat transfer portion side and the heat transfer tube on the downstream heat transfer portion side. As a result, a plurality of pipes for one round returning from the upstream heat transfer section to the upstream heat transfer section through the first communication section, the downstream heat transfer section, and the second communication section Helical pipes that are spirally repeated for minutes are constructed,
At the position where the plurality of heat transfer tubes constituting each of the first communication portion and the second communication portion are sandwiched from both the upper and lower sides, a suppressing portion that suppresses an excessive expansion of the interval between the plurality of heat transfer tubes is arranged. Established,
The heat exchanger according to any one of claims 1 to 4, wherein the holding portion is formed with one or more through holes penetrating in a vertical direction. Of the internal space of the casing, the downstream heat transfer unit is positioned at a position between the downstream heat transfer unit and the discharge port in the horizontal direction and at a position lower than the discharge port in the vertical direction. The heat exchanger as described in any one of Claims 1-5 in which the vent through which the said combustion exhaust gas which flows into the said exhaust port passes is provided.   A water heater comprising the heat exchanger according to any one of claims 1 to 6.

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