JP2014137208A - Heat exchanger and water heater including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger and a water heater capable of further improving heat exchange efficiency.SOLUTION: In a primary heat exchanger 11, a heat transfer tube 15 is arranged as one connected tube in each of lower and upper stages in such a manner as to reciprocate while penetrating a plurality of fins 13. A heat transfer tube 15b in the upper stage and a heat transfer tube 15a in the lower stage are arranged so that a perpendicular bisector V2 of the upper stage is offset to the other (rear) side with respect to a perpendicular bisector V1 of the lower stage, so that the heat transfer tube 15b in the upper stage is arranged to be offset to the rear side on which a discharge port 23a is provided with respect to the heat transfer tube 15a in the lower stage.

Description

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

  The heat exchanger is mainly configured by a plurality of plate-like fins, a heat transfer pipe penetrating the fins, a water supply pipe and a hot water pipe connected to the heat transfer pipe, a body plate as an exterior, and the like. In the water heater, for example, a burner for sending combustion gas to the heat exchanger is disposed below the heat exchanger. The heat transfer tubes are arranged on the side close to the burner (lower stage) and on the side farther (upper stage) in a manner of reciprocating while passing through the fins as one connected pipe. The water supply pipe is connected to one end side of the heat transfer pipe so that water flows from the heat transfer pipe arranged at the lower stage close to the burner to the heat transfer pipe arranged at the upper stage, and a hot water pipe is connected to the other end side opposite thereto. ing.

  In such a heat exchanger, the number of heat transfer tubes (cross-section) arranged in the lower stage and the number of heat transfer tubes (cross-section) arranged in the upper stage in the cross section in the direction substantially orthogonal to the direction in which the heat transfer tubes extend Are arranged with the same number, and there are an aspect in which the number of heat transfer tubes (cross sections) arranged in the lower stage is different from the number of heat transfer tubes (cross sections) arranged in the upper stage. Patent documents 1 and patent documents 2 are documents which disclose such a heat exchanger in which heat transfer tubes are arranged in a lower stage and an upper stage.

JP 2006-349234 A Japanese Patent Application Laid-Open No. 09-210463

  Conventionally, in a heat exchanger, it is required to efficiently bring a combustion gas into contact with a heat transfer tube and improve a heat exchange rate between water and the combustion gas in the heat exchanger.

  The present invention has been made as part of the development of such a heat exchanger, and one object is to provide a heat exchanger that can further improve the heat exchange rate, and the other object is to provide the heat exchanger. It is providing the water heater provided with such a heat exchanger.

  The heat exchanger according to the present invention has a plurality of fins and heat transfer tubes. Each of the plurality of fins has a main surface and is spaced from each other along a first direction intersecting the main surface. The heat transfer tube includes a plurality of through tubes each extending along the first direction so as to penetrate the plurality of fins, and is arranged as one connected tube. The heat transfer tube includes a first step portion and a second step portion. In the first step portion, among the plurality of through pipes, the plurality of first through pipes are respectively arranged along a second direction intersecting the first direction. In the second step portion, among the plurality of through pipes, a plurality of second through pipes are respectively disposed along the second direction. The pitch at which the plurality of first through pipes are arranged is different from the pitch at which the plurality of second through pipes are arranged. A 1st step part and a 2nd step part are the center located in one end among the several 1st through-tubes arrange | positioned along a 2nd direction, and the 1st step located in the other end. 2nd penetration located in one end among a plurality of 2nd penetration pipes arranged along the 2nd direction to the 1st perpendicular bisector of a line segment which connects the center of 1 penetration pipe It arrange | positions so that the 2nd perpendicular bisector of the line segment which connects the center of a pipe | tube and the center of the 2nd penetration pipe | tube located in the other end may shift | deviate to the other side.

  According to the heat exchanger according to the present invention, among the plurality of first through pipes, a line segment connecting the center of the first through pipe located at one end and the center of the first through pipe located at the other end. A line connecting the center of the second through pipe located at one end and the center of the second through pipe located at the other end of the plurality of second through pipes with respect to the first perpendicular bisector The second vertical bisector of the minute is arranged to be shifted to the other side. Thereby, combustion gas can be efficiently contacted with a heat exchanger tube, and a heat exchange rate can be improved.

  Further, each of the plurality of first through pipes is arranged with a first pitch as a pitch for arranging the plurality of first through pipes, and each of the plurality of second through pipes is a pitch for arranging the plurality of second through pipes. The second pitch is preferably set to be shorter than the first pitch.

  Thereby, combustion gas can be made to contact a heat exchanger tube more efficiently, and a heat exchange rate can be improved.

  Furthermore, among the plurality of first through pipes arranged along the second direction, the first through pipe located at one end and the plurality of second through pipes arranged along the second direction Among these, it is preferable that the pitch with the 2nd penetration pipe located in one end is set to the 2nd pitch.

Thereby, it can contribute to the cost reduction and size reduction of a heat exchanger.
A water heater according to the present invention is a water heater provided with the heat exchanger, and includes a combustion section and an exhaust collecting cylinder. A combustion part sends combustion gas into a heat exchanger. The exhaust collecting cylinder is disposed on the side opposite to the side where the combustion unit is disposed with the heat exchanger interposed therebetween, and has an outlet through which the combustion gas after heat exchange in the heat exchanger flows out. The first step portion is located on a side relatively close to the combustion portion. The second step portion is located on a side relatively far from the combustion portion. The outlet is disposed on the other side, and the second vertical bisector is shifted to the side where the outlet is disposed with respect to the first vertical bisector.

  According to the water heater according to the present invention, the heat exchange rate can be improved by providing the heat exchanger.

  Further, it is disposed so as to surround the plurality of fins, and includes a body plate including a pair of opposed side portions facing each other with a gap in the first direction, a water supply pipe and a hot water discharge pipe, and the number of first through pipes, The number of second through pipes is the same, and one end and the other end of the heat transfer tube are located on the side where one of the pair of opposing side portions is located, and one end of the heat transfer tube is It is preferable that a water supply pipe is connected from the side of the opposite side, and an outlet pipe is connected to the other end of the heat transfer pipe from the side of the one opposite side.

  Thereby, the length of the bypass pipe which connects a water supply pipe and a hot water discharge pipe can be shortened, and it can contribute to cost reduction.

It is the schematic which shows the structure of the hot water heater which concerns on embodiment of this invention. FIG. 3 is a first perspective view showing a burner, a primary heat exchanger, and a secondary heat exchanger in the water heater in the embodiment. In the embodiment, it is the 2nd perspective view which shows the burner, the primary heat exchanger, and the secondary heat exchanger in a water heater. FIG. 3 is a partial cross-sectional perspective view showing structures of a primary heat exchanger, an exhaust collecting cylinder, and a secondary heat exchanger in the same embodiment. In the embodiment, it is the 1st perspective view which shows the structure of a primary heat exchanger. In the embodiment, it is a 2nd perspective view which shows the structure of a primary heat exchanger. In the embodiment, it is sectional drawing of the direction orthogonal to the direction where a heat exchanger tube is extended of a primary heat exchanger. It is sectional drawing of the direction orthogonal to the direction where the heat exchanger tube is extended of the primary heat exchanger in the water heater which concerns on a comparative example. It is a figure which shows the flow of the combustion gas in the primary heat exchanger of the water heater which concerns on a comparative example. In the embodiment, it is a figure which shows the flow of the combustion gas in the primary heat exchanger of a water heater. In the embodiment, it is sectional drawing of the direction orthogonal to the direction where the heat exchanger tube is extended of the primary heat exchanger in the water heater which concerns on a modification. In the embodiment, it is a figure which shows the flow of the combustion gas in the primary heat exchanger of the water heater based on a modification. In the same embodiment, it is a figure for demonstrating the arrangement | positioning relationship of a heat exchanger tube. In the embodiment, it is the schematic which shows the structure of the water heater based on another modification.

  A water heater provided with the heat exchanger according to the embodiment will be described. As shown in FIG. 1, in a housing 2 of a water heater 1, a burner 3 that supplies combustion gas, a combustion fan 6 that sends air into the burner 3, a primary heat exchanger 11 that exchanges heat with the combustion gas, and a secondary A heat exchanger 21 is provided. In addition, the heat exchanger which concerns on this invention (claim) respond | corresponds to the primary heat exchanger 11, and the secondary heat exchanger 21 does not respond | correspond. A gas pipe 5 is connected to the burner 3. A water supply pipe 31 a is connected to the secondary heat exchanger 21, and a water supply pipe 31 b and a hot water discharge pipe 33 that have passed through the secondary heat exchanger 21 are connected to the primary heat exchanger 11. A bypass pipe 35 is connected between the water supply pipe 31 b and the hot water discharge pipe 33. In addition, a drain pipe 25 for discharging the drain generated in the secondary heat exchanger 21 is provided.

  Next, the primary heat exchanger 11 and the surrounding structure will be specifically described. As shown in FIGS. 2 and 3, the burner 3 is accommodated in the burner case 4. A combustion fan 6 is attached to the lower part of the burner case 4. Furthermore, as shown in FIG. 4, the primary heat exchanger 11 is accommodated in the trunk | drum 17 as an accommodation case. An exhaust collecting cylinder 23 is disposed on the primary heat exchanger 11. An outlet 23 a for supplying the combustion gas having passed through the primary heat exchanger 11 to the secondary heat exchanger 21 is formed in the exhaust collecting cylinder 23. The secondary heat exchanger 21 is provided with a plurality of water tubes 21a and an exhaust port 21b for exhausting combustion gas.

  Next, the structure of the primary heat exchanger 11 will be described in more detail. As shown in FIGS. 5 and 6, in the primary heat exchanger 11, the plurality of fins 13 having the main surface are arranged at intervals from each other in a direction substantially orthogonal to the main surface. In the drawings, fins 13 positioned at both ends and near the center are shown for the sake of simplicity and explanation. In a manner of reciprocating while passing through the plurality of fins 13, the heat transfer tubes 15 are arranged as one continuous tube on the lower stage relatively close to the burner 3 (see FIGS. 2 and 3) and the upper stage far away. . The tube diameter of the heat transfer tube 15 is, for example, 16 mmφ.

  The heat transfer tube 15 is formed by a straight tube 16 a as a through tube extending so as to penetrate the plurality of fins 13, and a U-shaped tube 16 b connecting adjacent straight tubes 16 a. A water supply pipe 31b is connected to one end side of the heat transfer pipe 15 so that water flows from the lower heat transfer pipe 15a toward the upper heat transfer pipe 15b, and a hot water discharge pipe 33 is connected to the other end side ( (See arrow in FIG. 6).

  Next, the arrangement structure of the heat transfer tubes 15 will be described. As shown in FIG. 7, in the lower heat transfer tubes 15a, the straight tubes 16a are respectively arranged with a first pitch P1 along a direction (second direction) substantially perpendicular to the extending direction (first direction). Has been. In the upper heat transfer tube 15b, the straight tubes 16a are arranged along the second direction with a second pitch P2 shorter than the first pitch P1. The number of lower straight tubes 16a (heat transfer tubes 15a) and the number of upper straight tubes 16a (heat transfer tubes 15b) are the same (four).

  Of the lower heat transfer tubes 15a and the upper heat transfer tubes 15b arranged along the second direction, the lower heat transfer tubes 15a (straight tubes 16a) and the upper heat transfer tubes respectively positioned at one (front) ends. The pitch with the heat pipe 15b (straight pipe 16a) is the second pitch P2. The first pitch P1 is, for example, 32 mm, and the second pitch P2 is, for example, 28 mm.

  Here, among the lower heat transfer tubes 15a (straight tubes 16a) arranged along the second direction, the center of the heat transfer tube 15a (straight tube 16a) located at one (front) end and the other (rear) The vertical bisector of the line segment S1 connecting the center of the heat transfer tube 15a (straight tube 16a) located at the end of the line is defined as a vertical bisector V1. Of the upper heat transfer tubes 15b (straight tubes 16a) arranged along the second direction, the center of the heat transfer tube 15b (straight tube 16a) located at one (front) end and the other (rear) The vertical bisector of the line segment S2 connecting the center of the heat transfer tube 15b (straight tube 16a) located at the end is defined as a vertical bisector V2.

  Then, in the primary heat exchanger 11 of the water heater 1, the upper heat transfer tube 15b and the lower heat transfer tube 15a have the vertical bisector V2 to the other (rear) side with respect to the vertical bisector V1. It is arranged so as to be displaced. That is, the upper heat transfer tube 15b is arranged so as to be shifted to the rear side where the outlet 23a is provided with respect to the lower heat transfer tube 15a. The primary heat exchanger 11 of the water heater 1 is configured as described above.

  Next, the operation of the above-described water heater will be described. When the operation switch is turned on and a predetermined amount of water is allowed to flow through the water supply pipe 31a, the combustion fan 6 starts to rotate and the burner 3 (see FIG. 2 or FIG. 3) ignites and burns upward from the burner 3. Gas is sent out. The sent combustion gas flows in the body plate 17 in which the primary heat exchanger 11 is arranged, and then flows in the secondary heat exchanger 21 through the outlet 23b of the exhaust collecting cylinder 23 (the arrow in FIG. 10). After that, the air is exhausted from the exhaust port 21b.

  On the other hand, the water sent from the water supply pipe 31 a first flows through the water pipe 21 a of the secondary heat exchanger 21. While flowing through the secondary heat exchanger 21, water is preheated by the combustion gas (latent heat). Next, the preheated water is sent to the primary heat exchanger 11 through the water supply pipe 31b. The preheated water sent to the primary heat exchanger 11 flows through the lower heat transfer tube 15a, and then flows through the upper heat transfer tube 15b. While water flows through the heat transfer tube 15, heat is exchanged between the combustion gas (sensible heat) flowing through the gap between the fins 13 and the fin 13 and the water, and the preheated water reaches a predetermined temperature. Heated. Hot water heated to a predetermined temperature is sent out of the water heater 1 through the hot water outlet pipe 33. Thus, hot water having a predetermined temperature can be supplied as the water heater 1.

  The effects of the water heater 1 including the primary heat exchanger 11 described above will be described in comparison with the case of the water heater according to the comparative example.

  As shown in FIG. 8, in the heat transfer tubes 115 in the primary heat exchanger 111 of the water heater 101 according to the comparative example, the number of lower straight tubes 116a (heat transfer tubes 115a) and the upper straight tubes 116a (heat transfer tubes 115b). Are the same number. Lower heat transfer tubes 115a (straight tubes 116a) are respectively arranged with a pitch PP1 along a direction (second direction) substantially perpendicular to the extending direction (first direction). The upper heat transfer tubes 115b (straight tubes 116a) are respectively arranged with a pitch PP2 along the second direction. The pitch PP1 and the pitch PP2 are the same pitch.

  Here, among the lower heat transfer tubes 115a (straight tubes 116a) arranged along the second direction, the center of the heat transfer tube 115a (straight tube 116a) located at one (front) end and the other (rear) The vertical bisector of the line segment SS1 connecting the center of the heat transfer tube 115a (straight tube 116a) located at the end of the line is defined as a vertical bisector VV1. Of the upper heat transfer tubes 115b (straight tubes 116a) arranged along the second direction, the center of the heat transfer tube 115b (straight tube 116a) located at one (front) end and the other (rear) A vertical bisector of the line segment SS2 connecting the center of the heat transfer tube 115b (straight tube 116a) located at the end is defined as a vertical bisector VV2.

  Then, in the water heater 101 according to the comparative example, the upper heat transfer tube 115b and the lower heat transfer tube 115a are arranged so that the vertical bisector VV1 and the vertical bisector VV2 substantially coincide with each other.

  An exhaust collecting cylinder 123 is disposed above the primary heat exchanger 111. The exhaust collecting cylinder 123 is formed with an outlet 123 a for sending the combustion gas that has flowed through the primary heat exchanger 111 to the secondary heat exchanger 121. The exhaust collecting cylinder 123 is arranged so that the outlet 123a is located on the rear side (right side as viewed in the drawing). Since the other configuration of the water heater 101 is the same as that of the water heater 1 shown in FIG. 2 and the like, the description thereof will not be repeated unless necessary.

  Next, the operation of the water heater 101 according to the comparative example will be described. As shown in FIG. 9, the combustion gas sent upward from the burner 103 first flows in the body plate 117 on which the primary heat exchanger 111 is arranged, and then, the outlet 123 a of the exhaust collecting cylinder 123. To the secondary heat exchanger 121 (see arrow YY), and then discharged to the outside through the exhaust port 121a.

  On the other hand, the water preliminarily heated by the secondary heat exchanger 121 and sent to the primary heat exchanger 111 is heated to a predetermined temperature by the combustion gas while flowing through the heat transfer tube 115. At this time, heat exchange is performed between the combustion gas flowing through the gap between the fin 113 and the water flowing through the heat transfer tube 115 passing through the fin 113.

  In the water heater 101 according to the comparative example, the lower heat transfer tube 115a and the upper stage are arranged so that the vertical bisector VV1 of the lower heat transfer pipe 115a and the vertical bisector VV2 of the upper heat transfer pipe 115b substantially coincide with each other. The heat transfer tube 115b is arranged. With respect to the arrangement of the heat transfer tubes 115a and 115b, since the combustion gas is sent from the outlet 123a to the secondary heat exchanger 121, the combustion gas is global (or dominant) from the burner 103 toward the outlet 123a. This flow of combustion gas becomes the main stream in the body plate 117.

  For this reason, among the upper heat transfer tubes 115b arranged on the downstream side of the flow of the combustion gas, the heat transfer located on the front side (the left side as viewed in the drawing) opposite to the side on which the outlet port 123a is arranged. Combustion gas is not in good contact with the heat pipe 115b, which is a factor that hinders increasing the heat exchange rate of the primary heat exchanger 111. On the other hand, on the side (rear) where the outlet 123a is disposed, the temperature of the trunk plate 117 may be excessively increased by the combustion gas that flows globally toward the outlet 123a.

  In contrast to the comparative example, in the water heater 1 according to the embodiment, as shown in FIG. 7, the upper heat transfer tube 15b and the lower heat transfer tube 15a are perpendicular to the vertical bisector V1. V2 is arranged so as to be shifted to the other (rear) side, and the upper heat transfer tube 15b located on the downstream side of the flow of the combustion gas has an outlet 23a with respect to the lower heat transfer tube 15a located on the upstream side. It is arranged so as to be shifted to the rear side where is provided.

  As a result, as shown in FIG. 10, more heat transfer tubes 15a and 15b are arranged in the general flow (main flow) of the combustion gas. As a result, the combustion gas can be reliably brought into contact with the heat transfer tubes 15a and 15b, and the heat exchange rate of the primary heat exchanger 11 can be increased. In addition, by increasing the heat exchange rate of the primary heat exchanger 11, it is possible to contribute to downsizing of the primary heat exchanger 11 and consequently downsizing of the water heater 1.

  Further, the upper heat transfer tube 15b located on the downstream side of the flow of the combustion gas approaches the rear side where the outlet 23a is provided, so that the heat exchange rate on the rear side increases, An excessive increase in temperature can also be suppressed.

  Moreover, in the primary heat exchanger 11 of the water heater 1 according to the embodiment, each of the lower heat transfer tubes 15a and the upper heat transfer tubes 15b arranged along the second direction is disposed at one (front) end. By setting the pitch between the lower heat transfer tube 15a and the upper heat transfer tube 15b to be the second pitch P2, the upper heat transfer tube 15b is connected to the lower heat transfer tube 15a and the upper heat transfer tube 15b. Connecting pipes that connect each other can be used, which can contribute to cost reduction.

  Further, in this case, the upper and lower sides of the primary heat exchanger 11 are compared with the case where the pitch between the lower heat transfer tube 15a and the upper heat transfer tube 15b respectively positioned at one (front) end is set to the first pitch P1. The size in the direction can be reduced, and the primary heat exchanger 11 can be made compact.

  Furthermore, in the hot water heater 1 described above, the case where the outlet 23a of the exhaust collecting cylinder 23 is disposed on the rear side is described as an example. However, as a hot water heater, the combustion gas is discharged from the rear of the water heater. The water heater may be arranged such that the exhaust port is disposed on the rear side and the outlet is disposed on the front side of the water heater. In the primary heat exchange of the hot water heater, the fins of the primary heat exchanger 11 of the hot water heater 1 described above may be disposed so as to be reversed, and an increase in cost can be suppressed.

  In addition, although the number of the lower straight pipes 16a (heat transfer tubes 15a) and the number of the upper straight pipes 16a (heat transfer tubes 15b) are the same as the primary heat exchanger 11 of the water heater 1 described above, As shown in FIG. 11, the number of lower straight pipes 16a (heat transfer tubes 15a) may be different from the number of upper straight pipes 16a (heat transfer tubes 15b).

  In the primary heat exchanger 11 of the water heater 1, the number of lower straight pipes 16a (heat transfer tubes 15a) is four, and the number of upper straight pipes 16a (heat transfer tubes 15b) is three. The lower heat transfer tubes 15a (straight tubes 16a) are arranged with a first pitch P1. The upper heat transfer tubes 15b (straight tubes 16a) are respectively arranged with a second pitch P2 longer than the first pitch P1.

  The upper heat transfer tube 15b and the lower heat transfer tube 15a are arranged such that the vertical bisector V2 is shifted to the other (rear) side with respect to the vertical bisector V1, and the upper heat transfer tube 15b is It arrange | positions so that it may shift | deviate to the back side in which the outflow port 23a is provided with respect to the heat exchanger tube 15a of the lower stage.

  As shown in FIG. 12, also in the primary heat exchanger 11 of the water heater 1 according to the modification, the upper heat transfer tube 15b is provided on the rear side where the outlet 23a is provided with respect to the lower heat transfer tube 15a. As a result, the heat transfer tubes 15a and 15b are arranged in a larger flow (main flow) of the combustion gas. As a result, the combustion gas can be reliably brought into contact with the heat transfer tubes 15a and 15b, and the heat exchange rate of the primary heat exchanger 11 can be increased. In addition, by increasing the heat exchange rate of the primary heat exchanger 11, it is possible to contribute to downsizing of the primary heat exchanger 11 and consequently downsizing of the water heater 1.

  Thus, in the primary heat exchanger 11 of the water heater 1 according to the embodiment, the upper heat transfer tube 15b and the lower heat transfer tube 15a have a vertical bisector V2 with respect to the vertical bisector V1, Although it has been described that the outlet 23a is arranged so as to be shifted to the rear side where the outlet 23a is arranged, the inventors examined the amount of deviation by setting the tube diameter of the heat transfer tube 15 to 16 mmφ, for example. As a result, as shown in FIG. 13, it was found that the desired effect can be obtained if the deviation D of the vertical bisector V2 with respect to the vertical bisector V1 is 1 mm or more.

  As shown in FIG. 6, in the primary heat exchanger 11 in which the number of the lower heat transfer tubes 15 a and the number of the upper heat transfer tubes 15 b are the same, one end of the heat transfer tube 15 to which the water supply pipe 31 b is connected, Both the other end of the heat transfer pipe 15 to which the hot water discharge pipe 33 is connected can be arranged on one side of the heat transfer pipe 15 (straight pipe 16a) extending in the first direction.

  Thereby, as shown in FIG. 3, the water supply pipe 31b and the hot water discharge pipe 33 are placed on one side portion on the side where one end and the other end of the heat transfer pipe are located on the body plate 17 surrounding the primary heat exchanger. It only has to be attached. As a result, the length of the bypass pipe 35 connecting the water supply pipe 31b and the hot water discharge pipe 33 can be shortened compared to the case where the one end and the other end of the heat transfer pipe are positioned to face each other, and the cost can be reduced. Can be achieved. The bypass pipe 35 is a pipe for mixing the supplied water without heating to the water (hot water) heated by the heat exchanger in order to supply hot water having a desired hot water temperature. is there.

  Moreover, in the hot water heater mentioned above, the hot water heater by which the primary heat exchanger was arrange | positioned above the burner was mentioned as an example, and was demonstrated (refer FIG. 1). The water heater is not limited to this type, and may be a water heater in which the primary heat exchanger 11 is disposed below the burner 3 as shown in FIG. In this case, the secondary heat exchanger 21 is disposed below the primary heat exchanger 11. Since this type of combustion system is mainly applied to a water heater that uses petroleum as a fuel, a fuel pipe 7 is connected to the burner 3.

  Further, in the above-described primary heat exchanger 11 of the water heater 1, the two-stage arrangement of the lower stage and the upper stage is described as an example of the arrangement of the heat transfer tubes 15, but it may be arranged in three or more stages. In particular, in the case of the two-stage arrangement, it is possible to contribute to the compactness of the primary heat exchanger 11. Moreover, the numerical value quoted as the tube diameter and pitch of the heat transfer tube 15 is an example, and is not limited thereto.

  The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the terms of the claims, rather than the scope described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is effectively used for a heat exchanger provided with a heat transfer tube penetrating a plurality of fins.

  DESCRIPTION OF SYMBOLS 1 Hot water heater, 2 Housings, 3 Burner, 4 Burner case, 5 Gas pipe, 6 Combustion fan, 7 Fuel pipe, 11 Primary heat exchanger, 13 Fin, 15 Heat transfer pipe, 15a Lower heat transfer pipe, 15b Upper heat transfer pipe , 16a Straight pipe, 16b U-shaped pipe, 17 Body plate, 21 Secondary heat exchanger, 21a Water pipe, 21b Exhaust port, 23 Exhaust gas collection tube, 23a Outlet, 25 Drain pipe, 31a, 31b Water supply pipe, 33 Hot water pipe , 35 Bypass pipe, S1, S2 line segment, V1, V2 vertical bisector, Y arrow.

Claims (5)

A plurality of fins each having a main surface and spaced apart from each other along a first direction intersecting the main surface;
Including a plurality of through tubes each extending along the first direction so as to penetrate the plurality of fins, and having a heat transfer tube arranged as one connected tube,
The heat transfer tube is
Among the plurality of through pipes, a plurality of first through pipes are respectively arranged along a second direction intersecting the first direction,
Among the plurality of through pipes, a plurality of second through pipes each include a second step portion disposed along the second direction,
Unlike the pitch for arranging the plurality of first through pipes and the pitch for arranging the plurality of second through pipes,
The first step portion and the second step portion are the center and the other end of the first through pipe located at one end among the plurality of first through pipes arranged along the second direction. Among the plurality of second through pipes arranged along the second direction with respect to a first perpendicular bisector of a line segment connecting the center of the first through pipe located at The second perpendicular bisector connecting the center of the second through pipe located at the end and the center of the second through pipe located at the other end is arranged so as to be shifted to the other side. ,Heat exchanger. Each of the plurality of first through pipes is arranged with a first pitch as a pitch for arranging the plurality of first through pipes,
Each of the plurality of second through pipes is arranged with a second pitch as a pitch for arranging the plurality of second through pipes,
The heat exchanger according to claim 1, wherein the second pitch is set shorter than the first pitch.   Of the plurality of first through pipes arranged along the second direction, the first through pipe located at the one end and the plurality of second through pipes arranged along the second direction. The heat exchanger according to claim 2, wherein a pitch of the second through pipe located at the one end among the through pipes is set to the second pitch. A water heater comprising the heat exchanger according to any one of claims 1 to 3,
A combustion section for sending combustion gas to the heat exchanger;
An exhaust collecting cylinder having an outlet that is disposed on the opposite side to the side where the combustion unit is disposed across the heat exchanger and through which the combustion gas after heat exchange in the heat exchanger flows out; With
The first stage portion is located on a side relatively close to the combustion portion,
The second step portion is located on a side relatively far from the combustion portion,
The outlet is disposed on the other side, and the second vertical bisector is shifted to the side where the outlet is disposed with respect to the first vertical bisector. vessel. A body plate including a pair of opposing side portions disposed so as to surround the plurality of fins and facing each other with a gap in the first direction;
It has a water supply pipe and a hot water pipe,
The number of the first through pipes and the number of the second through pipes are the same,
Both one end and the other end of the heat transfer tube are located on the side where one of the pair of opposing side portions is located,
The water supply pipe is connected to the one end of the heat transfer pipe from the side of the one opposing side,
The hot water heater according to claim 4, wherein the hot water discharge pipe is connected to the other end of the heat transfer pipe from the side of the one facing side.

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