JP7691738B2 - Water heater - Google Patents

Description

The present invention relates to a water heater.

The water heater described in Patent Document 1 is a latent heat recovery type, and is equipped with a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger is provided upstream of the burner exhaust path, and exchanges heat between the sensible heat of the combustion exhaust and the water passing through the heat transfer tube. The secondary heat exchanger is provided downstream of the exhaust path and above the primary heat exchanger, and exchanges heat between the latent heat in the combustion exhaust and the water passing through the heat transfer tube.

JP 2020-186885 A

In the above water heater, the casing of the secondary heat exchanger with an inlet at the rear is made of a drawn product from the standpoint of cost reduction, but to further reduce costs, it is preferable to also make the outlet part of the primary heat exchanger a drawn product. In that case, a path member is required to connect the outlet part and the casing of the secondary heat exchanger. From the standpoint of productivity and cost, it is desirable for such a path member to have a simple structure.

The object of the present invention is to provide a water heater in which the path member can be constructed with a simple structure.

The water heater of claim 1 includes a sensible heat recovery section provided upstream of an exhaust path through which a burner's combustion exhaust gas flows, for exchanging heat between sensible heat of the combustion exhaust gas and water passing through the exhaust gas; a latent heat recovery section provided downstream of the exhaust path and above the sensible heat recovery section, for exchanging heat between latent heat of the combustion exhaust gas that has passed through the sensible heat recovery section and water passing through the exhaust gas; and a route member provided at the rear of the sensible heat recovery section, connecting an outlet section that opens toward the rear and an inlet section that is provided at the rear of the latent heat recovery section, and directing the combustion exhaust gas discharged from the outlet section into the latent heat recovery section via the inlet section, the route member having a bulging section that bulges toward the rear and a flange-like protrusion that protrudes outward from a front end of the bulging section and extends in the vertical and horizontal directions. The exhaust gas turbine heater comprises a main body portion having a flange portion, and an erection portion erected between the left and right side portions of the flange portion so as to leave a predetermined gap in the front-to-rear direction between the rear wall of the bulge portion, the erection portion and the flange portion abutting the respective peripheral portions of the outlet portion and the inlet portion, an inlet port is formed in a portion surrounded by the erection portion and a lower half of the flange portion which is a portion lower than the erection portion, overlapping the outlet portion from the rear, for introducing the combustion exhaust gas in the sensible heat recovery portion into the route member, and an outlet is formed in a portion surrounded by the erection portion and an upper half of the flange portion which is a portion higher than the erection portion, overlapping the inlet portion from the rear, for leading the combustion exhaust gas in the route member into the latent heat recovery portion.

The water heater of claim 2 includes a sensible heat recovery section provided upstream of an exhaust path through which combustion exhaust from a burner flows, for exchanging sensible heat of the combustion exhaust with water, a discharge section provided downstream of the exhaust path and above the sensible heat recovery section, for receiving the combustion exhaust that has passed through the sensible heat recovery section and discharging it to the outside, and a route member provided at the rear of the sensible heat recovery section, connecting an outlet section that opens toward the rear and an inlet section that is provided at the rear of the discharge section and opens toward the rear, and directing the combustion exhaust discharged from the outlet section into the discharge section via the inlet section, the route member including a bulging section that bulges backward and a flange that protrudes outward from a front end of the bulging section in a flange-like shape and extends in the vertical and horizontal directions. The sensible heat recovery unit is characterized in that it comprises a main body portion having a flange portion and a mounting portion mounted between the left and right side portions of the flange portion so as to leave a predetermined gap in the front-to-rear direction between the rear wall of the bulge portion, the mounting portion and the flange portion abutting the respective peripheral portions of the outlet portion and the inlet portion, an inlet port is formed in a portion surrounded by the mounting portion and a lower half of the flange portion which is a portion lower than the mounting portion, overlapping the outlet portion from the rear, for introducing the combustion exhaust gas in the sensible heat recovery unit into the route member, and an outlet is formed in a portion surrounded by the mounting portion and an upper half of the flange portion which is a portion higher than the mounting portion, overlapping the inlet portion from the rear, for discharging the combustion exhaust gas in the route member into the exhaust portion.

According to the water heater of claim 1, the route member can be constructed with a very simple and small number of parts, namely, the main body with the bulge and the installation part. As a result, this embodiment can improve the productivity of the water heater and also save costs. The latent heat recovery section recovers the latent heat in the combustion exhaust, and if there is sensible heat that cannot be recovered in the sensible heat recovery section, it is recovered in the latent heat recovery section.

According to the water heater of claim 2, the route member can be constructed with a very simple and small number of parts, namely, the main body with the bulge and the installation part. As a result, this aspect can improve the productivity of the water heater and also reduce costs.

FIG. 1 is a perspective view of the internal structure of the water heater 1 (with the housing omitted). FIG. 2 is a perspective view of the primary heat exchanger 5 and the secondary heat exchanger 6 as viewed from the right rear. FIG. 2 is a cross-sectional perspective view of a primary heat exchanger 5 and a secondary heat exchanger 6. 2 is a cross-sectional view of a primary heat exchanger 5 and a secondary heat exchanger 6. FIG. FIG. 2 is a perspective view of a state in which a path unit 7 is disposed behind a primary heat exchanger 5 and a secondary heat exchanger 6. FIG. 2 is an exploded perspective view of the path unit 7. FIG. 8 is an exploded perspective view of the path unit 7 as viewed from an angle different from that of FIG. 7 . 13 is a perspective view of a straightening plate 70 having a fixed plate 31 fixed to its rear surface. FIG. 13 is a perspective view of a state in which a connecting plate 80 is disposed in front of a straightening plate 70. FIG. 13 is a perspective view of a state in which a straightening plate 70 is arranged on the front side of the cover portion 20. FIG. 13 is a perspective view showing a state in which a packing 90 is disposed on the front side of the cover portion 20 to which the connecting plate 80 is fixed. 13 is a right side view of the cover portion 20 to which the connecting plate 80 is fixed. FIG. 2 is a perspective view of the path unit 7 as seen obliquely from the front right. FIG. 4 is a cross-sectional view of the heat exchanger 500 and the exhaust box 600. FIG.

The following describes an embodiment of the present invention. Unless otherwise specified, the device configurations described below are not intended to be limiting, but are merely illustrative examples. The drawings are used to explain the technical features that may be adopted by the present invention. In the following description, the left/right, front/back, and up/down directions are indicated by arrows in the drawings.

The configuration of the water heater 1 will be described with reference to Figures 1 to 6. As shown in Figures 1 and 2, the water heater 1 is a gas water heater of the latent heat recovery type. The water heater 1 includes, from bottom to top, a fan 3, a combustion device 4, a primary heat exchanger 5, a secondary heat exchanger 6, and a path unit 7 (see Figure 3) within a housing 2 (see Figure 1).

The combustion device 4 has a square box-shaped inner case 4A. Inside the inner case 4A, multiple flat, light and dark burners (not shown) are arranged in a stacked state in the left-right direction. A fan 3 is fixed to the bottom of the inner case 4A and supplies combustion air into the inner case 4A. A gas supply unit 8 is fixed to the front of the inner case 4A. The gas supply unit 8 distributes and supplies gas to the multiple light and dark burners inside the inner case 4A. Inside the inner case 4A, the multiple light and dark burners burn a mixture of gas and air, generating combustion exhaust.

2 and 3, the primary heat exchanger 5 includes a peripheral wall 51, a heat transfer tube 52 (see FIG. 2), and an exhaust hood 53. The peripheral wall 51 is a generally rectangular tubular shape extending in the vertical direction, and is connected to the opening at the top of the inner case 4A. The peripheral wall 51 includes a right wall 511, a left wall 512, a front wall 513, and a rear wall 514. The peripheral wall 51 passes the combustion exhaust gas generated in the combustion device 4 from below to above. An inlet 55 is provided in the right wall 511. An outlet 56 is provided in the left wall 512. The heat transfer tube 52 is bent and arranged so as to make a plurality of reciprocating movements in the left-right direction within the peripheral wall 51 (see FIGS. 4 and 5). The heat transfer tube 52 is a water passage tube, and recovers sensible heat from the combustion exhaust gas passing from below to above within the peripheral wall 51. One upstream end of the heat transfer tube 52 is connected to the inlet 55, and one downstream end is connected to the outlet 56.

The exhaust hood 53 is provided to cover the opening at the top of the peripheral wall 51 and bulges upward. The rear wall 530 (see FIG. 6) of the exhaust hood 53 is rectangular in shape with its long sides in the left-right direction when viewed from the rear. An outlet 531 is provided in the rear wall 530. The outlet 531 is substantially rectangular in shape with its long sides in the left-right direction when viewed from the rear, and opens toward the rear. The outlet 531 allows the combustion exhaust gas in the exhaust hood 53 to flow out into the cover portion 20, which will be described later. Five fixing holes 58 are provided in the rear wall 530 on the right, left, and below the outlet 531.

2 and 3, the secondary heat exchanger 6 includes a housing 61, a heat transfer tube 62, and an exhaust section 63. The housing 61 includes a right wall 611, a left wall 612, a front wall 613, a rear wall 614 (see FIGS. 3 and 6), an upper wall 615 (see FIGS. 2, 4, and 5), and a bottom wall 616 (see FIGS. 4 and 5). The right wall 611 is provided with an inlet 65 and an outlet 66. The front wall 613 is provided with an opening 618 (see FIG. 4). The width of the housing 61 in the left-right direction is approximately the same as the width of the peripheral wall 51 of the primary heat exchanger 5 in the left-right direction. The length of the housing 61 in the front-rear direction is longer than the length of the peripheral wall 51 of the primary heat exchanger 5 in the front-rear direction. In a plan view, the position of the rear wall 614 is approximately the same as the position of the rear wall 514 of the peripheral wall 51 of the primary heat exchanger 5. Therefore, the position of the front wall 613 is a position that protrudes forward from the position of the front wall 513 of the peripheral wall 51 of the primary heat exchanger 5. The bottom wall 616 is disposed above the exhaust hood 53 of the primary heat exchanger 5.

As shown in FIG. 6, an inlet 617 is provided in the rear wall 614. The inlet 617 is generally rectangular and elongated in the left-right direction when viewed from the rear, and opens toward the rear. The left-right width of the inlet 617 is generally the same as the left-right width of the outlet 531. The inlet 617 allows the combustion exhaust gas flowing through the cover 20 (described below) to flow into the housing 61. Five fixing holes 68 are provided in the rear wall 614 on the right, left, and upper sides of the inlet 617.

The heat transfer tube 62 is bent and arranged so as to go back and forth multiple times in the left-right direction inside the housing 61 (see Figures 4 and 5). The heat transfer tube 62 is a water pipe, and recovers latent heat from the combustion exhaust gas from which sensible heat has been recovered by the primary heat exchanger 5. The secondary heat exchanger 6 recovers latent heat in the combustion exhaust gas, and if there is sensible heat that cannot be recovered by the primary heat exchanger 5, it is recovered in the heat transfer tube 62 of the secondary heat exchanger 6. One upstream end of the heat transfer tube 62 is connected to the inlet 65, and one downstream end is connected to the outlet 66.

The exhaust section 63 is provided on the front wall 613 (see Figures 1 and 2). The exhaust section 63 includes a flange portion 631 and an exhaust tube 632. The flange portion 631 is formed in a generally rectangular frame shape that is long in the left-right direction when viewed from the front, and is fixed to the front surface of the front wall 613. The exhaust tube 632 is provided to protrude forward from the inner edge of the opening of the flange portion 631, and is generally elliptical in shape that is long in the left-right direction when viewed from the front. The exhaust tube 632 is disposed in front of the opening 618 provided in the front wall 613 (see Figure 4). The exhaust tube 632 protrudes forward through the front cover (not shown) of the housing 2, and exhausts the combustion exhaust gas that has passed through the housing 61 to the outside of the housing 2.

As shown in Figures 4 to 6, the path unit 7 is provided so as to cover the rear wall 530 of the exhaust hood 53 of the primary heat exchanger 5 and the rear wall 614 of the secondary heat exchanger 6 from the rear. The path unit 7 includes a cover portion 20. The cover portion 20 is formed in a substantially rectangular shape that is substantially horizontally long when viewed from the rear, and the central portion of the substantially rectangular shape (rear wall 211 described later) excluding the outer edge portion bulges rearward. The cover portion 20 forms a space on the inside through which the exhaust gas passes from the outlet 531 to the inlet 617. As shown in Figures 4 and 5, a straightening plate 70 is supported within the cover portion 20. The straightening plate 70 divides the space within the cover portion 20 into two, and straightens the exhaust gas flowing within the cover portion 20 into two flows. The specific configuration of the path unit 7 will be described later.

The underside of the housing 2 is provided with a gas inlet 11, a water inlet 12, and a hot water outlet 13. An external gas pipe (not shown) is connected to the gas inlet 11. A water pipe (not shown) is connected to the water inlet 12. A piping (not shown) to a hot water tap is connected to the hot water outlet 13. The gas inlet 11 is connected to the gas supply unit 8 through a gas pipe 14 equipped with a main valve, a proportional valve, etc., inside the housing 2. The water inlet 12 is connected to the water supply section 15. The water supply section 15 is connected to the inlet 65 of the secondary heat exchanger 6 through water supply pipes 16A and 16B. The outlet 66 of the secondary heat exchanger 6 is connected to the inlet 55 of the primary heat exchanger 5 through a relay pipe 17. The outlet 56 of the primary heat exchanger 5 is connected to the hot water outlet 13 through the hot water outlet pipe 18. A bypass pipe 19 is connected between the water supply section 15 and the hot water outlet pipe 18. The bypass pipe 19 allows a portion of the water supplied from the water supply section 15 to merge with the hot water flowing through the hot water outlet pipe 18 without passing through the primary heat exchanger 5 and secondary heat exchanger 6.

The specific configuration of the path unit 7 will be described with reference to Figures 7 and 8. The path unit 7 includes, from the rear, a cover portion 20, a fixing plate 31, a straightening plate 70, a fixing plate 32, a connecting plate 80, and a packing 90.

The shape of the cover 20 will be described. The cover 20 forms a space inside through which the combustion exhaust gas flows. The cover 20 is formed from a metal plate that is generally rectangular when viewed from the back, and includes a bulge 21 and a flange 22. The bulge 21 is formed into a generally box-like shape with an open front surface by a rear wall 211 that is generally rectangular when viewed from the front, excluding the outer periphery, bulging rearward. The flange 22 protrudes outward in a flange-like shape from the front opening end of the bulge 21, and is formed into a generally rectangular frame shape that is horizontally long when viewed from the front. A pair of left and right protrusions 23 are provided at the center of the front surface of the rear wall 211, spaced apart from each other on the left and right. The protrusions 23 protrude forward.

A recess 26 is provided in the center of the vertical direction of each of the right and left sides of the flange portion 22. The recess 26 extends in the left-right direction so as to be perpendicular to the length direction of each of the right and left sides, and is recessed toward the rear. The depth of the recess 26 is approximately the same as the plate thickness of the connection plate 80 described below. A protrusion 27 is provided in the recess 26. The protrusion 27 protrudes forward. Three fixing holes 24 are provided at equal intervals in the left-right direction in each of the upper and lower parts of the flange portion 22. Two fixing holes 24 are provided in each of the right and left parts of the flange portion 22 at positions sandwiching the recess 26 in the center in the vertical direction. The size of the cover portion 20 when viewed from the back is approximately the same as the size of the rear wall 530 of the exhaust hood 53 of the primary heat exchanger 5 and the rear wall 614 of the secondary heat exchanger 6 connected vertically.

The shape of the straightening plate 70 will be described. The straightening plate 70 is a metal plate and includes a main body 71, a lower bent portion 72, and an upper bent portion 73. The main body 71 is formed in a generally rectangular shape that is long in the left-right direction when viewed from the front. A protrusion 711 (see FIG. 8) is provided at the bottom of the right end of the back surface of the main body 71. The protrusion 711 protrudes backward. A protrusion 712 (see FIG. 7) is provided at the top of the right end of the front surface of the main body 71. The protrusion 712 protrudes forward. A protrusion 713 (see FIG. 8) is provided at the top of the left end of the back surface of the main body 71. The protrusion 713 protrudes backward. A protrusion 714 (see FIG. 7) is provided at the bottom of the left end of the front surface of the main body 71.

A fixed piece 74 is provided at the right end of the main body 71, and a fixed piece 75 is provided at the left end. The fixed piece 74 is formed in a roughly L-shape in plan view, extending forward from the center of the right end of the main body 71, and the tip side is bent to the right. A protrusion 78 protruding forward is provided at the upper part of the front surface of the tip 741 of the fixed piece 74 extending to the right. The fixed piece 75 is symmetrical to the fixed piece 74, and is formed in a roughly inverted L-shape in plan view. The fixed piece 75 extends forward from the center of the left end of the main body 71, and the tip side is bent to the left. A protrusion 79 protruding forward is provided at the lower part of the front surface of the tip 751 of the fixed piece 75 extending to the left. The lower bent part 72 is bent forward from the lower end of the main body 71 in a roughly arc shape in side view. The upper bent portion 73 bends forward from the upper end of the main body portion 71 in a generally arc-like shape when viewed from the side.

The shapes of the fixed plates 31 and 32 will be described. Note that the fixed plates 31 and 32 are common parts, so the shape of the fixed plate 31 will be described. The fixed plate 31 has a central portion 35, a first fixed portion 36, and a second fixed portion 37. The left-right length of the fixed plate 31 is approximately the same as the left-right length of the main body portion 71 of the straightening plate 70. The central portion 35 is formed in an approximately U-shape that opens toward the front in a plan view and is approximately rectangular in shape that is long in the left-right direction when viewed from the front. A pair of left and right holes 351 are provided in the central portion 35. The pair of holes 351 correspond to a pair of protrusions 23 provided on the front surface of the rear wall 211 of the cover portion 20.

The first fixing part 36 extends rightward from the front end of the right side of the central part 35, and is formed in a generally inverted U-shape that opens downward when viewed from the rear. A pair of upper and lower fixing holes 361 are provided on the right end side of the first fixing part 36. The second fixing part 37 extends leftward from the front end of the left side of the central part 35, and is formed in a generally U-shape that opens upward when viewed from the rear. A pair of upper and lower fixing holes 371 are provided on the left end side of the second fixing part 37. The fixing holes 361, 371 penetrate in the front-rear direction.

As will be described later, fixed plate 31 is fixed to the rear side of straightening plate 70, and fixed plate 32 is fixed to the front side of straightening plate 70. Fixed plate 32 is oriented in the opposite front-to-back direction to fixed plate 31, with the inside of the opening of central portion 35 facing rearward. The first fixed portion 36 located on the right side is roughly U-shaped and opens toward the upper side when viewed from the front. The second fixed portion 37 located on the left side is roughly inverted U-shaped and opens toward the lower side when viewed from the front. As described above, fixed plates 31 and 32 are common parts, making storage and management easy.

The shape of the connection plate 80 will be described. The connection plate 80 is a metal plate and is formed in a generally rectangular shape elongated in the left-right direction when viewed from the front. The connection plate 80 includes a main body 81, a right fixing part 82, and a left fixing part 83. The main body 81 is the central part of the connection plate 80 in the left-right direction and is formed in a generally rectangular shape elongated in the left-right direction when viewed from the front. A pair of upper and lower protrusions 84 extend in the left-right direction and parallel to each other on the front surface of the main body 81. The protrusions 84 protrude forward from the front surface of the main body 81 in a rib shape. The protrusions 84 improve the rigidity of the main body 81. A fixing hole 87 penetrating in the front-rear direction is provided in the upper part of the right end of the main body 81. A fixing hole 88 penetrating in the front-rear direction is provided in the lower part of the left end of the main body 81.

The right fixing part 82 is provided at the right end of the main body part 81. The right fixing part 82 is formed in a generally rectangular shape that is long in the vertical direction when viewed from the front. The right fixing part 82 is approximately the same size as the recess 26 provided on the right side of the flange part 22 of the cover part 20. A fixing hole 85 is provided in the center of the right fixing part 82. A rib 821 that protrudes forward is provided at the right end of the right fixing part 82. The left fixing part 83 is provided at the left end of the main body part 81. The left fixing part 83 is formed in a generally rectangular shape that is long in the vertical direction when viewed from the front. The left fixing part 83 is also approximately the same size as the recess 26 provided on the left end of the flange part 22 of the cover part 20. A fixing hole 86 is provided in the center of the left fixing part 83. A rib 831 that protrudes forward is provided at the left end of the left fixing part 83.

The shape of the packing 90 will be described. The packing 90 is made of, for example, synthetic resin, and has a thickness of approximately 3 mm. The packing 90 includes a frame portion 91 and a plate portion 92. The frame portion 91 is formed in a generally rectangular frame shape that is long in the left-right direction when viewed from the front, and is approximately the same size as the cover portion 20. The widths of the upper, lower, right, and left sides of the frame portion 91 are approximately the same as the width of the flange portion 22.

The plate-shaped portion 92 is installed between the center of the right inner edge portion and the center of the left inner edge portion of the inner periphery of the opening inside the frame-shaped portion 91, and is formed in a substantially rectangular shape that is long in the left-right direction when viewed from the front. An upper opening 93 is formed on the upper side of the plate-shaped portion 92, and a lower opening 94 is formed on the lower side of the plate-shaped portion 92. The upper opening 93 and the lower opening 94 are formed in a substantially rectangular shape that is long in the left-right direction when viewed from the front. Three fixing holes 95 are provided in each of the upper and lower parts of the frame-shaped portion 91. The three fixing holes 95 are arranged on the right side, center, and left side of each of the upper and lower parts. Two fixing holes 95 are provided in each of the right and left parts of the frame-shaped portion 91. The two fixing holes 95 are arranged in positions corresponding to the upper opening 93 and the lower opening 94 in each of the upper and lower parts.

An example of an assembly method of the path unit 7 will be described. For the sake of convenience, the orientation of each part when assembling the path unit 7 will be described following the orientation when it is housed in the water heater 1. First, as shown in Figures 7 and 8, the assembly worker places the fixing plate 31 on the back side of the main body 71 of the straightening plate 70. The first fixing part 36 and the second fixing part 37 are each abutted against the back side of the main body 71 from behind. At this time, the lower fixing hole 361 provided on the right end side of the first fixing part 36 of the fixing plate 31 is engaged with the protrusion 711 provided at the lower part of the right end side of the back side of the main body 71 to position it. Furthermore, the upper fixing hole 371 provided on the left end side of the second fixing part 37 of the fixing plate 31 is engaged with the protrusion 713 provided at the upper part of the left end side of the back side of the main body 71 to position it.

In this state, the overlapping portion W1 (see FIG. 9) of the first fixing portion 36 and the main body portion 71 is sandwiched from the front and rear by a pair of electrode lobes (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W1 is the portion where the upper portion of the substantially inverted U-shaped first fixing portion 36 on the opposite side to the opening side overlaps with the main body portion 71. Furthermore, the overlapping portion W2 of the second fixing portion 37 and the main body portion 71 is sandwiched from the front and rear by a pair of electrode lobes (not shown) of the spot welding machine, and spot welding is performed. The overlapping portion W2 is the portion where the lower portion of the substantially U-shaped second fixing portion 37 on the opposite side to the opening side overlaps with the main body portion 71. As a result, the fixing plate 31 is fixed to the back surface of the main body portion 71 (see FIG. 9).

Then, the fixing plate 32 is placed on the front side of the main body 71 of the straightening plate 70. As described above, the orientation of the fixing plate 32 is opposite to that of the fixing plate 31 in the up-down and front-back directions. The first fixing part 36 and the second fixing part 37 are each abutted against the front side of the main body 71. At this time, the upper fixing hole 361 provided on the right end side of the first fixing part 36 of the fixing plate 31 is engaged with the protrusion 712 provided on the upper part of the right end side of the front side of the main body 71 to position it. Furthermore, the lower fixing hole 371 provided on the left end side of the first fixing part 36 of the fixing plate 31 is engaged with the protrusion 714 provided on the lower part of the left end side of the front side of the main body 71 to position it.

In this state, the first fixing portion 36 of the fixing plate 32 and the overlapping portion W3 (see FIG. 10) of the main body portion 71 are sandwiched from the front and rear by a pair of electrode lobes (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W3 is a portion where the lower portion of the substantially U-shaped first fixing portion 36 on the opposite side to the opening side overlaps with the main body portion 71. Furthermore, the second fixing portion 37 of the fixing plate 32 and the overlapping portion W4 of the main body portion 71 are sandwiched from the front and rear by a pair of electrode lobes (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W4 is a portion where the upper portion of the substantially inverted U-shaped first fixing portion 36 on the opposite side to the opening side overlaps with the main body portion 71. As a result, the fixing plate 32 is fixed to the front surface of the main body portion 71 (see FIG. 10).

In this way, spot welding is a method of welding two metal plates by applying pressure and current to them. Therefore, it is necessary to fix the fixed plate 31 to the back surface of the main body 71, and then fix the fixed plate 31 to the front surface of the main body 71, or in the reverse order. The part sandwiched between the pair of electrode lobes of the spot welding machine must be two metal sheets. Therefore, in this embodiment, the first and second fixed parts 36 and 37 of the fixed plates 31 and 32 are formed into an approximately U-shape, and when the fixed plates 31 and 32 are positioned on the back surface and front surface of the main body 71 of the rectifying plate 70, the first and second fixed parts 36 and 37 are arranged so that they are upside down and upside down through the main body 71. As a result, when the rectifying plate 70 is seen through from the front side to the rear side, the overlapping parts W3 and W4 of the fixed plate 32 and the main body 71 do not overlap with the overlapping parts W1 and W2 of the fixed plate 31 and the main body 71. Therefore, because the overlapping portions W1 to W4 are made of two metal plates, each portion can be spot welded, and as a result, the fixing plates 31 and 32 can be fixed to the straightening plate 70 by spot welding.

Next, as shown in FIG. 10, the connection plate 80 is placed in the left-right direction in front of the rectifying plate 70 to which the fixing plate 32 is fixed on the front side. The right end side of the main body 81 is placed in front of the tip 741 of the fixing piece 74 of the rectifying plate 70, and the fixing hole 87 provided on the right end side of the main body 81 is positioned to the protrusion 78 of the fixing piece 74 of the rectifying plate 70. At the same time, the left end side of the main body 81 is placed in front of the tip 751 of the fixing piece 75 of the rectifying plate 70, and the fixing hole 88 provided on the left end side of the main body 81 is positioned to the protrusion 79 of the fixing piece 75 of the rectifying plate 70. In this state, the right end side of the main body 81 is spot welded to the front of the tip 741 of the fixing piece 74, and the left end side of the main body 81 is spot welded to the front of the tip 751 of the fixing piece 75. As a result, the connection plate 80 is fixed to the fixing pieces 74, 75 of the rectifying plate 70, and is in a state of being installed in the left-right direction between the fixing pieces 74, 75 (see FIG. 11). The back surface of the main body 81 of the connection plate 80 abuts against the front surface of the center portion 35 of the fixing plate 32. Therefore, the center portion of the connection plate 80 is stably supported by the fixing plate 32, the rectifying plate 70, and the fixing plate 31.

Next, as shown in FIG. 11, the straightening plate 70 to which the fixing plates 31, 32 and the connecting plate 80 are fixed is placed on the front side of the cover part 20. The back surface of the central part 35 of the fixing plate 31, which is fixed to the back surface of the straightening plate 70, is placed on the front surface of the rear wall 211 of the cover part 20. The pair of left and right holes 351 provided in the central part 35 are positioned relative to the pair of left and right protrusions 23 provided on the front surface of the rear wall 211, and spot welding is performed from the front. As a result, the straightening plate 70 is fixed to the front surface of the rear wall 211 of the cover part 20 via the fixing plate 31.

The right fixing portion 82 of the connection plate 80 is placed in front of the recess 26 provided on the right side of the flange portion 22 of the cover portion 20. At this time, the fixing hole 85 provided in the right fixing portion 82 of the connection plate 80 is positioned relative to the protrusion 27 provided on the front side of the recess 26. The left fixing portion 83 of the connection plate 80 is placed in front of the recess 26 provided on the left side of the flange portion 22 of the cover portion 20. At this time, the fixing hole 86 provided in the left fixing portion 83 of the connection plate 80 is positioned relative to the protrusion 27 provided on the front side of the recess 26. In this state, the right fixing portion 82 and the left fixing portion 83 of the connection plate 80 are spot welded to the corresponding pair of left and right recesses 26, 26. As a result, the right and left ends of the connection plate 80 are fixed to the right and left sides of the flange portion 22 of the cover portion 20 (see FIG. 12).

As shown in FIG. 12, a lower half 121 and an upper half 122 are formed on the front surface of the flange portion 22. The lower half 121 is a portion below the connecting plate 80, and is formed in a generally U-shape when viewed from the front. The upper half 122 is a portion above the connecting plate 80, and is upside down compared to the lower half 121, and is formed in a generally inverted U-shape when viewed from the front, opening downward. An inlet 151 is formed in the portion surrounded by the lower half 121 and the connecting plate 80. An outlet 152 is formed in the portion surrounded by the upper half 122 and the connecting plate 80. The inlet 151 and the outlet 152 are both generally rectangular and horizontally long when viewed from the front.

The inlet 151 corresponds to the outlet 531 of the primary heat exchanger 5. The inlet 151 is an opening for introducing the exhaust gas from the outlet 531 into the cover 20. The outlet 152 corresponds to the inlet 617 of the secondary heat exchanger 6. The outlet 152 is an opening for discharging the exhaust gas that has passed through the cover 20 toward the inlet 617.

The depth of the recesses 26 is approximately the same as the plate thickness of each of the right and left fixing parts 82 and 83 of the connecting plate 80. Therefore, as shown in FIG. 13, the difference in level between the front surface of each of the right and left fixing parts 82 and 83 and the front surface of the flange part 22 can be reduced. Inside each recess 26, a sealant 200 is applied to the gap Q that occurs on the outer periphery of each of the right and left fixing parts 82 and 83. As a result, the inside of each recess 26 is horizontally filled with the right or left fixing part 82 or 83 and the sealant 200, so the difference in level with the front surface of the flange part 22 can be reduced.

Next, as shown in FIG. 12, the packing 90 is attached from the front with adhesive to the flange portion 22 of the cover portion 20 to which the straightening plate 70 and the connection plate 80 are fixed. As shown in FIG. 14, the frame portion 91 of the packing 90 is attached to the front surface of the flange portion 22. The plate portion 92 of the packing 90 is attached to the front surface of the connection plate 80. At this time, the right end of the frame portion 91 abuts against the left surface of the rib 821 of the right fixing portion 82 of the connection plate 80, and the left end of the frame portion 91 abuts against the right surface of the rib 831 of the left fixing portion 83 of the connection plate 80. The upper end of the plate portion 92 abuts against the lower surface of the rib 811 at the upper end of the main body portion 81 of the connection plate 80, and the lower end of the plate portion 92 abuts against the lower surface of the rib 812 at the lower end of the main body portion 81 of the connection plate 80. This prevents the packing 90 from shifting position relative to the flange portion 22 of the cover portion 20 and the connection plate 80. In this way, the path unit 7 is completed.

6, the completed path unit 7 is pressed from behind against the rear wall 530 of the exhaust hood 53 of the primary heat exchanger 5 and the rear wall 614 of the secondary heat exchanger 6. At this time, the lower half 121 (see FIG. 12) of the flange portion 22 of the cover portion 20 abuts against the rear surface of the rear wall 530 of the primary heat exchanger 5, and the right, left, and lower sides of the outlet 531, via the packing 90. The upper half 122 (see FIG. 12) of the flange portion 22 abuts against the rear surface of the rear wall 614 of the secondary heat exchanger 6, and the right, left, and upper sides of the inlet 617, via the packing 90. The front surface of the connection plate 80 abuts against the boundary portion 101. The boundary portion 101 is the portion between the outlet 531 and the inlet 617. The inlet 151 provided on the lower front side of the cover 20 is positioned opposite the outlet 531 of the primary heat exchanger 5, and the outlet 152 provided on the upper front side is positioned opposite the inlet 617 of the secondary heat exchanger 6.

The ten fixing holes 24 provided in the flange portion 22 are arranged through the ten fixing holes 95 provided in the packing 90 to the five fixing holes 58 provided in the rear wall 530 of the primary heat exchanger 5 and the five fixing holes 68 provided in the rear wall 614 of the secondary heat exchanger 6. Ten screws 45 are inserted from the rear into the ten fixing holes 24 provided in the flange portion 22, and fastened to the five fixing holes 58 and the five fixing holes 68 through the ten fixing holes 95 of the packing 90. As a result, the path unit 7 is stably and firmly fixed by covering the rear walls 530, 614 of the primary heat exchanger 5 and the secondary heat exchanger 6 from the rear (see FIG. 3).

As shown in Figures 4 and 5, within the cover 20, the straightening plate 70 is supported at a position spaced forward from the front surface of the rear wall 211 of the bulge 21. The main body 71 of the straightening plate 70 divides the space within the cover 20 into front and rear. This actively introduces the exhaust gas into the front portion of the internal space of the cover 20. This prevents vortexes of the exhaust gas from being generated in the internal space of the cover 20, thereby preventing pressure loss.

In this embodiment, the main portion of the path unit 7 through which the combustion exhaust gas passes from the outlet 531 to the inlet 617 can be constructed with a very simple and small number of parts, namely the cover portion 20 and the connection plate 80. This makes it easy to assemble the path unit 7, improving the productivity of the water heater 1 and saving costs.

In addition, the fixing plate 31, the straightening plate 70, and the fixing plate 32 are fixed to the front surface of the rear wall 211 of the bulging portion 21 of the cover portion 20, and the connecting plate 80 is fixed to the fixing plate 32. This allows the water heater 1 to effectively apply the tightening force of the screw 45 to the packing 90 located behind the boundary portion 101 via the bulging portion 21, the fixing plate 31, the straightening plate 70, and the fixing plate 32. This allows the water heater 1 to suitably crush the packing 90, so that the path unit 7 can be tightly attached to the respective peripheries of the outlet 531 and the inlet 617, and to the boundary portion 101 between the outlet 531 and the inlet 617. Therefore, the water heater 1 can prevent the leakage of combustion exhaust gas despite its simple configuration.

In addition, the outlet 531 and the inlet 617 are rectangular and longer in the left-right direction than in the up-down direction, so the central part of the boundary 101 between them, which is the left-right center part where leakage is likely to occur, can be indirectly suppressed by the connecting plate 80 via the gasket 90, thereby achieving good sealing.

The connection plate 80 is fixed to the front surface of the flange portion 22 of the cover portion 20 in a position that sandwiches the bulge portion 21 in the center. This allows the water heater 1 to apply the tightening stress of the screws 45 more directly and uniformly to the boundary portion 101. This allows the water heater 1 to further improve the sealing performance of the cover portion 20.

The depth of the recesses 26 provided on both the left and right sides of the flange portion 22 is approximately the same as the plate thickness of the right fixing portion 82 and the left fixing portion 83 of the connecting plate 80, so that the front surfaces of the right fixing portion 82 and the left fixing portion 83 are flush with the front surface of the flange portion 22. This allows the packing 90 to be in close contact with the front surface of the flange portion 22, further improving the sealing performance of the cover portion 20.

Two protrusions 84 are provided on the front surface of the connection plate 80. The protrusions 84 protrude forward and extend parallel to the length of the boundary portion 101. This allows the water heater 1 to more suitably crush the gasket 90 corresponding to the boundary portion 101, thereby further improving the sealing performance of the cover portion 20.

In the above description, the exhaust hood 53 outlet 531 is an example of the "outlet portion" of the present invention, and the inlet 617 is an example of the "inlet portion" of the present invention. The route unit 7 is an example of the "route member" of the present invention. The cover portion 20 is an example of the "main body portion" of the present invention. The connection plate 80 is an example of the "installation portion" of the present invention. Furthermore, the "sensible heat recovery portion" of the present invention is a portion that recovers sensible heat in the exhaust gas from combustion, and in this embodiment of the specification, is a concept that includes the primary heat exchanger 5 and the exhaust hood 53. Furthermore, the "latent heat recovery portion" of the present invention is a portion that recovers latent heat in the exhaust gas from combustion, and in this embodiment of the specification, is a concept that includes the secondary heat exchanger 6.

As described above, the water heater 1 of this embodiment includes a primary heat exchanger 5, a secondary heat exchanger 6, and a path unit 7. The primary heat exchanger 5 is provided upstream of the combustion exhaust path of the multiple light and dark burners housed in the combustion device 4. The primary heat exchanger 5 includes a peripheral wall 51 and an exhaust hood 53. The peripheral wall 51 houses multiple heat transfer tubes 52 extending in the left-right direction. The primary heat exchanger 5 exchanges heat between the sensible heat of the combustion exhaust flowing through the peripheral wall 51 and the exhaust hood 53 and the water passing through the heat transfer tube 52. The secondary heat exchanger 6 is provided downstream of the combustion exhaust path and adjacent to the upper side of the primary heat exchanger 5. The secondary heat exchanger 6 includes a housing 61. The housing 61 houses multiple heat transfer tubes 62 extending in the left-right direction. The secondary heat exchanger 6 exchanges heat between the latent heat of the combustion exhaust flowing through the housing 61 and the water passing through the heat transfer tube 62. An outlet port 531 that opens toward the rear is provided on the rear wall 530 of the exhaust hood 53 of the primary heat exchanger 5. An inlet port 617 that opens toward the rear is provided on the rear wall 614 of the housing 61 of the secondary heat exchanger 6.

The path unit 7 is fixed from the rear so as to cover the outlet 531 and the inlet 617. The path unit 7 guides the combustion exhaust gas discharged from the outlet 531 into the housing 61 through the inlet 617. The path unit 7 includes a cover portion 20 and a connection plate 80. The cover portion 20 includes a bulging portion 21 and a flange portion 22. The bulging portion 21 bulges rearward. The flange portion 22 expands in the up -down and left -right directions from the front end of the bulging portion 21. The connection plate 80 is installed between the left and right side portions of the flange portion 22 so as to leave a predetermined gap between the rear wall 211 of the bulging portion and the connection plate 80 in the front-rear direction. The connection plate 80 and the flange portion 22 abut against the respective peripheral portions of the outlet 531 and the inlet 617 via a packing 90.

An inlet 151 is formed in the area surrounded by the connecting plate 80 and the lower half 121 of the flange portion 22. The lower half 121 is a portion of the front surface of the flange portion 22 that is lower than the connecting plate 80. The inlet 151 overlaps the outlet 531 from the rear and introduces the combustion exhaust gas in the exhaust hood 53 into the cover portion 20. An outlet 152 is formed in the area surrounded by the connecting plate 80 and the upper half 122 of the flange portion 22. The upper half 122 is a portion of the front surface of the flange portion 22 that is upper than the connecting plate 80. The outlet 152 overlaps the inlet 617 from the rear and introduces the combustion exhaust gas in the cover portion 20 into the housing 61 of the secondary heat exchanger 6. In this way, the water heater 1 can configure the main part of the path unit 7 with extremely simple and few parts, namely the cover portion 20 and the connecting plate 80. As a result, this embodiment allows the path unit 7 to be easily assembled, improving the productivity of the water heater 1 and reducing costs.

The present invention is not limited to the above embodiment, and various modifications are possible. The peripheral wall 51 and the exhaust hood 53 of the primary heat exchanger 5 are separate bodies, but may be integrated. The outlet 531 and the inlet 617 do not have to be rectangular in shape. The flange portion 22 of the cover portion 20 is fastened to the rear walls 530 and 614 with ten screws 45, but the number of screws 45 and the fastening positions are not limited to the above embodiment. The number of heat transfer tubes 52 and 62 extending in the left-right direction is also not limited. Of the path unit 7, the fixing plates 31 and 32 and the straightening plate 70 may be omitted. When the straightening plate 70 is omitted, the fixing plates 31 and 32 may be integrated and abutted against the rear surface of the connecting plate 80. The packing 90 may also be omitted, but it is preferable to abut the cover 20 and the connection plate 80 via the packing 90 in order to closely contact the rear walls 530, 614 of the primary heat exchanger 5 and the secondary heat exchanger 6, respectively.

The assembly method of the path unit 7 is not limited to the above embodiment. In the above embodiment, the fixing plates 31, 32 are fixed to the front and rear of the straightening plate 70, and the connecting plate 80 is fixed to the front side, and then the whole is fixed to the front side of the cover part 20, but the order in which the components are fixed may be changed. For example, the fixing plates 31, 32 may be fixed to the front and rear of the straightening plate 70, and then the whole may be fixed to the inside of the cover part 20, and then the connecting plate 80 may be fixed from the front side.

The water heater 1 is provided with a secondary heat exchanger 6 adjacent to the upper side of the primary heat exchanger 5, but may be a sensible heat recovery type water heater provided with an exhaust box 600 instead of the secondary heat exchanger 6, as shown in FIG. 15, for example. The exhaust box 600 is provided adjacent to the upper side of the heat exchanger 500. The heat exchanger 500 has the same configuration as the primary heat exchanger 5, and is an example of the "sensible heat recovery section" of the present invention. The exhaust box 600 is approximately box-shaped with the heat transfer tube 62 omitted from the inside of the housing 61 of the secondary heat exchanger 6. The exhaust box 600 receives the combustion exhaust gas flowing from the path unit 7 and exhausts it to the outside from the exhaust section 63. The exhaust box 600 is an example of the "exhaust section" of the present invention. In this configuration, the straightening plate 70 (see FIG. 5) in the path unit 7 is omitted, and the fixing plates 31 and 32 are integrated into one fixing member 300. Even in such a modified example, the same effect as in the above embodiment can be obtained.

REFERENCE SIGNS LIST 1 water heater 5 primary heat exchanger 6 secondary heat exchanger 7 path unit 20 cover portion 21 bulge portion 22 flange portion 53 exhaust hood 80 connection plate 121 lower portion 122 upper portion 500 heat exchanger 530 rear wall 531 outlet 600 exhaust box 614 rear wall 617 inlet

Claims (2)

a sensible heat recovery section provided upstream of an exhaust passage through which the burner combustion exhaust flows, for exchanging sensible heat of the combustion exhaust with water;
a latent heat recovery section provided downstream of the exhaust path and above the sensible heat recovery section for exchanging heat between the latent heat of the combustion exhaust gas that has passed through the sensible heat recovery section and water;
a path member that connects an outlet portion provided at a rear portion of the sensible heat recovery portion and opening toward the rear, and an inlet portion provided at a rear portion of the latent heat recovery portion and opening toward the rear, and that guides the combustion exhaust gas discharged from the outlet portion into the latent heat recovery portion through the inlet portion;
The pathway member includes:
a main body portion including a rearwardly expanding bulging portion and a flange portion that protrudes outward from a front end portion of the bulging portion in a flange-like shape and expands in the vertical and horizontal directions;
a bridge portion that is bridged between the left and right side portions of the flange portion so as to leave a predetermined gap between the bridge portion and a rear wall of the bulging portion in the front-rear direction,
The bridge portion and the flange portion abut against the peripheral portions of the outlet portion and the inlet portion,
an inlet for introducing the combustion exhaust gas in the sensible heat recovery unit into the path member is formed in a portion surrounded by the installation portion and a lower half portion of the flange portion that is a portion lower than the installation portion, the inlet overlapping the outlet portion from the rear;
This water heater is characterized in that an outlet is formed in the area surrounded by the installation portion and the upper half of the flange portion, which is the portion above the installation portion, overlapping the inlet portion from the rear, for directing the combustion exhaust gas in the route member into the latent heat recovery section. a sensible heat recovery section provided upstream of an exhaust passage through which the burner combustion exhaust flows, for exchanging sensible heat of the combustion exhaust with water;
an exhaust section provided downstream of the exhaust path and above the sensible heat recovery section, for receiving the combustion exhaust gas that has passed through the sensible heat recovery section and discharging it to the outside;
a path member that connects an outlet portion provided at a rear portion of the sensible heat recovery portion and opening toward the rear, and an inlet portion provided at a rear portion of the exhaust portion and opening toward the rear, and that guides the combustion exhaust gas discharged from the outlet portion into the exhaust portion through the inlet portion,
The pathway member includes:
a main body portion including a rearwardly expanding bulging portion and a flange portion that protrudes outward from a front end portion of the bulging portion in a flange-like shape and expands in the vertical and horizontal directions;
a bridge portion that is bridged between the left and right side portions of the flange portion so as to leave a predetermined gap between the bridge portion and a rear wall of the bulging portion in the front-rear direction,
The bridge portion and the flange portion abut against the peripheral portions of the outlet portion and the inlet portion,
an inlet for introducing the combustion exhaust gas in the sensible heat recovery unit into the path member is formed in a portion surrounded by the installation portion and a lower half portion of the flange portion that is a portion lower than the installation portion, the inlet overlapping the outlet portion from the rear;
This water heater is characterized in that an outlet is formed in the area surrounded by the installation portion and the upper half of the flange portion, which is the portion above the installation portion, overlapping the inlet portion from the rear, for directing the combustion exhaust gas in the route member into the exhaust portion.

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