Water heater

Abstract

To provide a water heater capable of configuring a path member with a simple structure.SOLUTION: A path unit 7 is equipped with a covering portion 20 and a connection plate 80. The covering portion 20 is equipped with a bulging portion 21 and a flange portion 22. The connection plate 80 is laid between both right and left portions of the flange portion 22. The connection plate 80 and the flange portion 22 abut on the respective peripheral portions of an outflow port 531 and an inflow port 617 through a packing 90. In a part surrounded by the connection plate 80 and a lower half portion of the flange portion 22, an introduction port is formed. The introduction port overlaps the outflow port 531 from a rear side, and introduces combustion exhaust in an exhaust hood 53 into the covering portion 20. In a part surrounded by the connection plate 80 and an upper half portion of the flange portion 22, a lead-out port is formed. The lead-out port overlaps the inflow port 617 from a rear side, and combustion exhaust in the covering portion 20 is led out into a housing 61 of a secondary heat exchanger 6.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a water heater.

Background Art

[0002] The water heater described in Patent Document 1 is a latent heat recovery type and includes a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger is provided upstream of the exhaust path of the burner and performs heat exchange between the sensible heat of the combustion exhaust and the water flowing through the heat transfer pipe. The secondary heat exchanger is provided downstream of the exhaust path and above the primary heat exchanger, and performs heat exchange between the latent heat in the combustion exhaust and the water flowing through the heat transfer pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above water heater uses a drawn product for the casing of the secondary heat exchanger provided with an inlet at the rear from the viewpoint of cost reduction. However, in order to further reduce costs, it is preferable that the outlet component of the primary heat exchanger is also a drawn product. Then, a path member is required to communicate the outlet component with the casing of the secondary heat exchanger. From the viewpoints of productivity and cost, a simple configuration is desirable for such a path member.

[0005] An object of the present invention is to provide a water heater capable of configuring a path member with a simple configuration.

Means for Solving the Problems

[0006] The water heater according to claim 1 is provided on the upstream side of an exhaust path through which the combustion exhaust gas of the burner flows, and includes a sensible heat recovery unit for exchanging sensible heat of the combustion exhaust gas with the flowing water, and a latent heat recovery unit provided on the downstream side of the exhaust path and above the sensible heat recovery unit for exchanging latent heat of the combustion exhaust gas that has passed through the sensible heat recovery unit with the flowing water. An outlet portion is provided at the rear of the sensible heat recovery unit and opens rearward, and an inlet portion is provided at the rear of the latent heat recovery unit and opens rearward. A path member is provided to connect the two, and to guide the combustion exhaust gas discharged from the outlet portion into the latent heat recovery unit through the inlet portion. The path member includes a bulging portion that bulges rearward, and a main body portion including a flange portion that extends in the left-right direction from the front end portion of the bulging portion. A bridging portion is provided between the left and right side portions of the flange portion so as to form a predetermined gap in the front-rear direction with the rear wall of the bulging portion. The bridging portion and the flange portion are in contact with the peripheral portions of the outlet portion and the inlet portion respectively. An inlet port is formed in a portion surrounded by the bridging portion and a lower half portion of the flange portion that is below the bridging portion, which overlaps the outlet portion from the rear to introduce the combustion exhaust gas in the sensible heat recovery unit into the path member. An outlet port is formed in a portion surrounded by the bridging portion and an upper half portion of the flange portion that is above the bridging portion, which overlaps the inlet portion from the rear to guide the combustion exhaust gas in the path member into the latent heat recovery unit. It protrudes in a flange shape outward, in the vertical direction and The water heater is characterized in that it further includes a bridging portion provided between the left and right side portions of the flange portion so as to form a predetermined gap in the front-rear direction with the rear wall of the bulging portion. The bridging portion and the flange portion are in contact with the peripheral portions of the outlet portion and the inlet portion respectively. An inlet port is formed in a portion surrounded by the bridging portion and a lower half portion of the flange portion that is below the bridging portion, which overlaps the outlet portion from the rear to introduce the combustion exhaust gas in the sensible heat recovery unit into the path member. An outlet port is formed in a portion surrounded by the bridging portion and an upper half portion of the flange portion that is above the bridging portion, which overlaps the inlet portion from the rear to guide the combustion exhaust gas in the path member into the latent heat recovery unit.

[0007] The water heater according to claim 2 is provided on the upstream side of an exhaust path through which the combustion exhaust gas of the burner flows, and includes a sensible heat recovery unit for exchanging sensible heat of the combustion exhaust gas with the flowing water, and a discharge unit provided on the downstream side of the exhaust path and above the sensible heat recovery unit for receiving the combustion exhaust gas that has passed through the sensible heat recovery unit and discharging it to the outside. An outlet portion is provided at the rear of the sensible heat recovery unit and opens rearward, and an inlet portion is provided at the rear of the discharge unit and opens rearward. A path member is provided to connect the two, and to guide the combustion exhaust gas discharged from the outlet portion into the discharge unit through the inlet portion. The path member includes a bulging portion that bulges rearward, and a main body portion including a flange portion that extends in the left-right direction from the front end portion of the bulging portion. It protrudes in a flange shape outward, in the vertical direction and A main body portion having a flange portion extending in the left - right direction, and a bridging portion bridged between both left and right side portions of the flange portion so as to provide a predetermined gap in the front - rear direction between the bridging portion and the rear wall of the bulging portion. The bridging portion and the flange portion are in contact with the peripheral portions of the outlet portion and the inlet portion respectively. An inlet for introducing the combustion exhaust gas in the sensible heat recovery portion into the path member is formed in a portion surrounded by the bridging portion and a lower half portion which is a portion of the flange portion below the bridging portion, overlapping the outlet portion from the rear. An outlet for leading the combustion exhaust gas in the path member into the discharge portion is formed in a portion surrounded by the bridging portion and an upper half portion which is a portion of the flange portion above the bridging portion, overlapping the inlet portion from the rear.

Advantages of the Invention

[0008] According to the water heater of claim 1, the path member can be constituted by an extremely simple and small number of parts, namely, the main body portion having the bulging portion and the bridging portion. Thereby, this aspect can improve the productivity of the water heater and also save costs. Note that the latent heat recovery portion recovers the latent heat in the combustion exhaust gas. However, if there is sensible heat that could not be completely recovered in the sensible heat recovery portion, it will be recovered in the latent heat recovery portion.

[0009] According to the water heater of claim 2, the path member can be constituted by an extremely simple and small number of parts, namely, the main body portion having the bulging portion and the bridging portion. Thereby, this aspect can improve the productivity of the water heater and also save costs.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described. The device configurations and the like described below are not intended to be limited to only those, without specific descriptions, but are merely illustrative examples. The drawings are used to explain the technical features that can be adopted by the present invention. The following description uses left - right, front - back, and up - down indicated by arrows in the figures.

[0012] Referring to FIGS. 1 to 6, the configuration of the water heater 1 will be described. As shown in FIGS. 1 and 2, the water heater 1 is a latent heat recovery type gas water heater. The water heater 1 includes a fan 3, a combustion device 4, a primary heat exchanger 5, a secondary heat exchanger 6, and a path unit 7 (see FIG. 3) in order from the bottom in a housing 2 (see FIG. 1).

[0013] The combustion device 4 includes a rectangular box-shaped inner case 4A. Inside the inner case 4A, a plurality of flat-type lean-rich burners (not shown) are arranged in a stacked state in the left-right direction. The fan 3 is fixed to the lower part of the inner case 4A and supplies combustion air into the inner case 4A. A gas supply unit 8 is fixed to the front surface of the inner case 4A. The gas supply unit 8 distributes and supplies gas to the plurality of lean-rich burners inside the inner case 4A. Inside the inner case 4A, combustion exhaust gas is generated when the plurality of lean-rich burners burn the gas-air mixture.

[0014] As shown in FIGS. 2 and 3, the primary heat exchanger 5 includes a peripheral wall 51, heat transfer tubes 52 (see FIG. 2), and an exhaust hood 53. The peripheral wall 51 is in a substantially rectangular cylindrical shape extending in the vertical direction and is connected to the upper opening 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 allows the combustion exhaust gas generated by the combustion device 4 to pass from below upward. An inlet 55 is provided in the right wall 511. An outlet 56 is provided in the left wall 512. The heat transfer tubes 52 are bent and arranged to reciprocate a plurality of times in the left-right direction inside the peripheral wall 51 (see FIGS. 4 and 5). The heat transfer tubes 52 are water pipes and recover sensible heat from the combustion exhaust gas passing from below upward inside the peripheral wall 51. One end portion on the upstream side of the heat transfer tubes 52 is connected to the inlet 55, and one end portion on the downstream side is connected to the outlet 56.

[0015] The exhaust hood 53 is provided so as to cover the upper opening of the peripheral wall 51 and bulges upward. The rear wall 530 (see FIG. 6) of the exhaust hood 53 is in a rectangular shape that is long in the left-right direction when viewed from the rear. An outflow port 531 is provided in the rear wall 530. The outflow port 531 is in a substantially rectangular shape that is long in the left-right direction when viewed from the rear and opens rearward. The outflow port 531 allows the combustion exhaust gas inside the exhaust hood 53 to flow out into the covering portion 20 described later. In the rear wall 530, five fixing holes 58 are provided on the right side, left side, and lower side of the outflow port 531.

[0016] As shown in FIGS. 2 and 3, the secondary heat exchanger 6 includes a housing 61, heat transfer tubes 62, and an exhaust portion 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). An inlet 65 and an outlet 66 are provided in the right wall 611. An opening 618 (see FIG. 4) is provided in the front wall 613. The lateral width of the housing 61 in the left-right direction is substantially the same as the lateral width of the peripheral wall 51 of the primary heat exchanger 5. The longitudinal length of the housing 61 in the front-rear direction is longer than the longitudinal length of the peripheral wall 51 of the primary heat exchanger 5 in the front-rear direction. In plan view, the position of the rear wall 614 is substantially 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 protruding 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.

[0017] As shown in FIG. 6, an inlet 617 is provided in the rear wall 614. The inlet 617 is substantially rectangular and long in the left-right direction in a rear view, and opens rearward. The lateral width of the inlet 617 is substantially the same as the lateral width of the outlet 531. The inlet 617 allows the combustion exhaust flowing in the covering portion 20 described later to flow into the housing 61. Five fixing holes 68 are provided on the right side, left side, and upper side of the inlet 617 in the rear wall 614.

[0018] The heat transfer tubes 62 are bent and arranged to reciprocate a plurality of times in the left-right direction within the housing 61 (see FIGS. 4 and 5). The heat transfer tubes 62 are water pipes that recover the latent heat from the combustion exhaust whose sensible heat has been recovered by the primary heat exchanger 5. Although the secondary heat exchanger 6 recovers the latent heat in the combustion exhaust, if there is any sensible heat that could not be completely recovered by the primary heat exchanger 5, it is recovered by the heat transfer tubes 62 of the secondary heat exchanger 6. One end portion on the upstream side of the heat transfer tubes 62 is connected to the inlet 65, and one end portion on the downstream side is connected to the outlet 66.

[0019] The exhaust section 63 is provided on the front wall 613 (see FIGS. 1 and 2). The exhaust section 63 includes a flange section 631 and an exhaust pipe 632. The flange section 631 is formed in a substantially 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 pipe 632 is provided so as to protrude forward from the inner edge of the opening of the flange section 631, and is substantially oval in shape that is long in the left-right direction when viewed from the front. The exhaust pipe 632 is disposed on the front side of the opening 618 provided in the front wall 613 (see FIG. 4). The exhaust pipe 632 penetrates through the front cover (not shown) of the housing 2 and protrudes forward, discharging the combustion exhaust that has passed through the housing 61 to the outside of the housing 2.

[0020] As shown in FIGS. 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 covering portion 20. The covering portion 20 is formed in a substantially horizontally long rectangular shape when viewed from the back, and a substantially rectangular central portion (the rear wall 211 described later), excluding its outer edge portion, bulges backward. Inside the covering portion 20, a space is formed through which the combustion exhaust passes from the outlet 531 toward the inlet 617. As shown in FIGS. 4 and 5, a rectifying plate 70 is supported inside the covering portion 20. The rectifying plate 70 divides the space inside the covering portion 20 into two, and rectifies the combustion exhaust flowing through the covering portion 20 into two flows. The specific configuration of the path unit 7 will be described later.

[0021] On the lower surface of the housing 2, a gas inlet 11, a water inlet 12, and a hot water outlet 13 are provided. 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 pipe (not shown) to a hot water faucet is connected to the hot water outlet 13. The gas inlet 11 is connected to the gas supply unit 8 in the housing 2 via a gas pipe 14 provided with an original valve, a proportional valve, etc. 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 via 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 via a relay pipe 17. The outlet 56 of the primary heat exchanger 5 is connected to the hot water outlet 13 via a hot water pipe 18. A bypass pipe 19 is connected between the water supply section 15 and the hot water pipe 18. The bypass pipe 19 merges a part of the water supplied from the water supply section 15 into the hot water flowing through the hot water pipe 18 without passing through the primary heat exchanger 5 and the secondary heat exchanger 6.

[0022] Referring to FIGS. 7 and 8, the specific configuration of the path unit 7 will be described. The path unit 7 includes, in order from the rear, a covering portion 20, a fixing plate 31, a rectifying plate 70, a fixing plate 32, a connecting plate 80, and a packing 90.

[0023] The shape of the covering portion 20 will be described. The covering portion 20 forms a space inside which the combustion exhaust flows. The covering portion 20 is formed of a metal plate having a substantially rectangular shape in a rear view, and includes a bulging portion 21 and a flange portion 22. The bulging portion 21 is formed in a substantially box shape with an open front by a rear wall 211 having a substantially rectangular shape in a front view excluding the outer peripheral edge portion bulging rearward. The flange portion 22 protrudes outward in a flange shape from the open end on the front side of the bulging portion 21, and is formed in a substantially rectangular frame shape that is horizontally long in a front view. A pair of left and right protrusions 23 arranged at intervals left and right are provided at the center of the front surface of the rear wall 211. The protrusions 23 protrude forward.

[0024] At the vertical center of each of the right and left sides of the flange portion 22, a recess 26 is provided. The recess 26 extends in the left-right direction so as to be orthogonal to the length direction of each of the right and left sides, and is formed to be recessed rearward. The depth of the recess 26 is substantially the same as the plate thickness of a connection plate 80 described later. 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 sides of the flange portion 22. Two fixing holes 24 are provided in each of the right and left sides of the flange portion 22 at positions sandwiching the recess 26 at the vertical center. The size of the cover portion 20 in a rear view is substantially the same as the size obtained by vertically connecting 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.

[0025] The shape of the rectifying plate 70 will be described. The rectifying plate 70 is a metal plate and includes a main body portion 71, a lower bent portion 72, and an upper bent portion 73. The main body portion 71 is formed in a substantially rectangular shape that is long in the left-right direction in a front view. A protrusion 711 (see FIG. 8) is provided at the lower part of the right end of the back surface of the main body portion 71. The protrusion 711 protrudes rearward. A protrusion 712 (see FIG. 7) is provided at the upper part of the right end of the front surface of the main body portion 71. The protrusion 712 protrudes forward. A protrusion 713 (see FIG. 8) is provided at the upper part of the left end of the back surface of the main body portion 71. The protrusion 713 protrudes rearward. A protrusion 714 (see FIG. 7) is provided at the lower part of the left end of the front surface of the main body portion 71.

[0026] A fixing piece 74 is provided at the right end of the main body portion 71, and a fixing piece 75 is provided at the left end. The fixing piece 74 is formed in a substantially L shape in plan view, extends forward from the center of the right end of the main body portion 71, and bends and extends to the right at the tip side. A protrusion 78 protruding forward is provided at the upper part of the front surface of the tip portion 741 extending to the right of the fixing piece 74. The fixing piece 75 has a shape symmetrical to the left and right with the fixing piece 74 and is formed in a substantially reverse L shape in plan view. The fixing piece 75 extends forward from the center of the left end of the main body portion 71, and bends and extends to the left at the tip side. A protrusion 79 protruding forward is provided at the lower part of the front surface of the tip portion 751 extending to the left of the fixing piece 75. The lower bending portion 72 bends in a substantially arc shape in side view from the lower end of the main body portion 71 forward. The upper bending portion 73 bends in a substantially arc shape in side view from the upper end of the main body portion 71 forward.

[0027] The shapes of the fixing plates 31 and 32 will be described. Since the fixing plates 31 and 32 are common parts to each other, the shape of the fixing plate 31 will be described. The fixing plate 31 includes a central portion 35, a first fixing portion 36, and a second fixing portion 37. The length of the fixing plate 31 in the left-right direction is substantially the same as the length of the main body portion 71 of the rectifying plate 70 in the left-right direction. The central portion 35 is formed in a substantially U shape that opens forward in plan view and in a substantially rectangular shape that is long in the left-right direction in front view. A pair of 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 covering portion 20.

[0028] The first fixing portion 36 extends rightward from the front end portion on the right side of the central portion 35 and is formed in a substantially reverse U shape that opens downward in rear view. A pair of upper and lower fixing holes 361 are provided on the right end side of the first fixing portion 36. The second fixing portion 37 extends leftward from the front end portion on the left side of the central portion 35 and is formed in a substantially U shape that opens upward in rear view. A pair of upper and lower fixing holes 371 are provided on the left end side of the second fixing portion 37. The fixing holes 361 and 371 penetrate in the front-rear direction.

[0029] As will be described later, the fixing plate 31 is fixed to the back side of the rectifying plate 70, and the fixing plate 32 is fixed to the front side of the rectifying plate 70. The fixing plate 32 is opposite to the front and rear directions of the fixing plate 31, and is arranged with the inner side where the central portion 35 opens facing rearward. The first fixing portion 36 located on the right side is substantially U-shaped and opens upward in a front view. The second fixing portion 37 located on the left side is substantially reverse U-shaped and opens downward in a front view. As described above, since the fixing plates 31 and 32 are common parts to each other, storage management is easy.

[0030] The shape of the connection plate 80 will be described. The connection plate 80 is a metal plate and is formed in a substantially rectangular shape that is elongated in the left-right direction in a front view. The connection plate 80 includes a main body portion 81, a right fixing portion 82, and a left fixing portion 83. The main body portion 81 is the central portion of the connection plate 80 in the left-right direction and is formed in a substantially rectangular shape that is elongated in the left-right direction in a front view. On the front surface of the main body portion 81, a pair of upper and lower protruding portions 84 extend in the left-right direction and are parallel to each other. The protruding portions 84 protrude forward from the front surface of the main body portion 81 in a rib shape. The protruding portions 84 improve the rigidity of the main body portion 81. A fixing hole 87 penetrating in the front-rear direction is provided in the upper part of the right end portion of the main body portion 81. A fixing hole 88 penetrating in the front-rear direction is provided in the lower part of the left end portion of the main body portion 81.

[0031] The right fixing portion 82 is provided at the right end portion of the main body portion 81. The right fixing portion 82 is formed in a substantially rectangular shape that is long in the up-down direction in a front view. The right fixing portion 82 has substantially the same size as the concave portion 26 provided on the right side portion of the flange portion 22 of the covering portion 20. A fixing hole 85 is provided at the center of the right fixing portion 82. A rib 821 protruding forward is provided at the right end portion of the right fixing portion 82. The left fixing portion 83 is provided at the left end portion of the main body portion 81. The left fixing portion 83 is formed in a substantially rectangular shape that is long in the up-down direction in a front view. The left fixing portion 83 also has substantially the same size as the concave portion 26 provided on the left end portion of the flange portion 22 of the covering portion 20. A fixing hole 86 is provided at the center of the left fixing portion 83. A rib 831 protruding forward is provided at the left end portion of the left fixing portion 83.

[0032] Describe the shape of the packing 90. The packing 90 is formed of, for example, synthetic resin, and its thickness is about 3 mm. The packing 90 includes a frame-shaped portion 91 and a plate-shaped portion 92. The frame-shaped portion 91 is formed in a substantially rectangular frame shape that is long in the left-right direction in a front view, and is substantially the same size as the covering portion 20. The width of each of the upper side portion, the lower side portion, the right side portion, and the left side portion of the frame-shaped portion 91 is substantially the same as the width of the flange portion 22.

[0033] The plate-shaped portion 92 is installed between the central portions of the right inner edge portion and the left inner edge portion of the inner peripheral edge 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 in a front view. An upper opening 93 is formed above the plate-shaped portion 92, and a lower opening 94 is formed below 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 in a front view. Three fixing holes 95 are provided in each of the upper side portion and the lower side portion of the frame-shaped portion 91. The three fixing holes 95 are arranged on the right side, the center, and the left side of each of the upper side portion and the lower side portion. Two fixing holes 95 are provided in each of the right side portion and the left side portion of the frame-shaped portion 91. The two fixing holes 95 are arranged at positions corresponding to the upper opening 93 and the lower opening 94, respectively, in each of the upper side portion and the lower side portion.

[0034] Describe an example of the assembling method of the path unit 7. For the sake of convenience of explanation, regarding the orientation of each component when assembling the path unit 7, the description will follow the orientation in the state of being housed in the water heater 1. First, as shown in FIGS. 7 and 8, the assembler arranges the fixing plate 31 on the back side of the main body portion 71 of the rectifying plate 70. Each of the first fixing portion 36 and the second fixing portion 37 is brought into contact with the back surface of the main body portion 71 from the rear. At this time, the lower fixing hole 361 provided on the right end side of the back surface of the main body portion 71 is engaged with the protrusion 711 provided at the lower part of the right end side of the first fixing portion 36 of the fixing plate 31 for positioning. Further, the upper fixing hole 371 provided on the left end side of the second fixing portion 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 surface of the main body portion 71 for positioning.

[0035] In this state, the overlapping portion W1 (see Fig. 9) between the first fixing portion 36 and the main body portion 71 is sandwiched from the front and rear directions by a pair of electrode sleeves (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W1 is a portion where the upper portion on the side opposite to the opening side of the substantially inverted U-shaped first fixing portion 36 overlaps with the main body portion 71. Further, the overlapping portion W2 between the second fixing portion 37 and the main body portion 71 is sandwiched from the front and rear directions by a pair of electrode sleeves (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W2 is a portion where the lower portion on the side opposite to the opening side of the substantially U-shaped second fixing portion 37 overlaps with the main body portion 71. Thereby, the fixing plate 31 is fixed to the back surface of the main body portion 71 (see Fig. 9).

[0036] Next, the fixing plate 32 is disposed on the front side of the main body portion 71 of the rectifying plate 70. As described above, the orientation of the fixing plate 32 is opposite to that of the fixing plate 31 in terms of up and down and front and rear. Each of the first fixing portion 36 and the second fixing portion 37 is brought into contact with the front surface of the main body portion 71. At this time, the upper fixing hole 361 provided on the right end side of the first fixing portion 36 of the fixing plate 31 is engaged with and positioned with respect to the protrusion 712 provided on the upper portion of the right end side of the front surface of the main body portion 71. Further, the lower fixing hole 371 provided on the left end side of the first fixing portion 36 of the fixing plate 31 is engaged with and positioned with respect to the protrusion 714 provided on the lower portion of the left end side of the front surface of the main body portion 71.

[0037] In this state, the overlapping portion W3 (see Fig. 10) between the first fixing portion 36 of the fixing plate 32 and the main body portion 71 is sandwiched from the front and rear directions by a pair of electrode sleeves (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W3 is a portion where the lower portion on the side opposite to the opening side of the substantially U-shaped first fixing portion 36 overlaps with the main body portion 71. Further, the overlapping portion W4 between the second fixing portion 37 of the fixing plate 32 and the main body portion 71 is sandwiched from the front and rear directions by a pair of electrode sleeves (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W4 is a portion where the upper portion on the side opposite to the opening side of the substantially inverted U-shaped first fixing portion 36 overlaps with the main body portion 71. Thereby, the fixing plate 32 is fixed to the front surface of the main body portion 71 (see Fig. 10).

[0038] Thus, spot welding is a method of welding by applying current while sandwiching two metal plates and applying pressure. Therefore, after fixing the fixing plate 31 to the back surface of the main body 71, it is necessary to fix the fixing plate 31 to the front surface of the main body 71, or vice versa. And the portion sandwiched by the pair of electrode sleeves of the spot welder must be two metals. Therefore, in the present embodiment, the first fixing portions 36 and the second fixing portions 37 of the fixing plates 31 and 32 are each formed in a substantially U shape, and when the fixing plates 31 and 32 are positioned on the back surface and the front surface of the main body 71 of the rectifying plate 70, the first fixing portions 36 and the second fixing portions 37 are arranged so that they are vertically reversed with respect to each other via the main body 71. Thereby, when the rectifying plate 70 is viewed through from the front side to the rear, the overlapping portions W3 and W4 of the fixing plate 32 and the main body 71 do not overlap the overlapping portions W1 and W2 of the fixing plate 31 and the main body 71. Therefore, since there are two metal plates in the overlapping portions W1 to W4, it is possible to spot weld each portion, and as a result, the fixing plates 31 and 32 can be fixed to the rectifying plate 70 by spot welding.

[0039] Next, as shown in FIG. 10, the connection plate 80 is arranged in the left-right direction on the front side of the rectifying plate 70 to which the fixing plate 32 is fixed to the front surface. The right end side of the main body 81 is arranged on the front surface of the tip portion 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 on 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 arranged on the front surface of the tip portion 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 on the protrusion 79 of the fixing piece 75 of the rectifying plate 70. In this state, spot welding is performed on the front surface of the tip portion 741 of the fixing piece 74 at the right end side of the main body 81, and spot welding is performed on the front surface of the tip portion 751 of the fixing piece 75 at the left end side of the main body 81. Thereby, the connection plate 80 is fixed to the fixing pieces 74 and 75 of the rectifying plate 70, and is in a state of being laid in the left-right direction between the fixing pieces 74 and 75 (see FIG. 11). The back surface of the main body 81 of the connection plate 80 abuts on the front surface of the central portion 35 of the fixing plate 32. Therefore, the central portion of the connection plate 80 is stably supported by the fixing plate 32, the rectifying plate 70, and the fixing plate 31.

[0040] Next, as shown in FIG. 11, the rectifying plate 70 to which the fixing plates 31 and 32 and the connection plate 80 are fixed is disposed on the front side of the covering portion 20. The back surface of the central portion 35 of the fixing plate 31 fixed to the back surface of the rectifying plate 70 is disposed on the front surface of the rear wall 211 of the covering portion 20. The pair of left and right holes 351 provided in the central portion 35 are positioned with respect 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. Thereby, the rectifying plate 70 is fixed to the front surface of the rear wall 211 of the covering portion 20 via the fixing plate 31.

[0041] Furthermore, the right fixing portion 82 of the connection plate 80 is disposed on the front surface of the recess 26 provided in the right side portion of the flange portion 22 of the covering portion 20. At this time, the fixing hole 85 provided in the right fixing portion 82 of the connection plate 80 is positioned with respect to the protrusion 27 provided on the front surface of the recess 26. Also, the left fixing portion 83 of the connection plate 80 is disposed on the front surface of the recess 26 provided in the left side portion of the flange portion 22 of the covering portion 20. At this time, the fixing hole 86 provided in the left fixing portion 83 of the connection plate 80 is positioned with respect to the protrusion 27 provided on the front surface of the recess 26. In this state, spot welding is performed on the right fixing portion 82 and the left fixing portion 83 of the connection plate 80 with respect to the pair of left and right corresponding recesses 26 and 26. Thereby, the right end portion and the left end portion of the connection plate 80 are fixed to the right side portion and the left side portion of the flange portion 22 of the covering portion 20 (see FIG. 12).

[0042] As shown in FIG. 12, a lower half portion 121 and an upper half portion 122 are respectively formed on the front surface of the flange portion 22. The lower half portion 121 is a portion below the connection plate 80 and is formed in a substantially U shape in a front view. The upper half portion 122 is a portion above the connection plate 80 and has a shape opposite to that of the lower half portion 121, and is formed in a substantially inverted U shape opening downward in a front view. An inlet 151 is formed in the portion surrounded by the lower half portion 121 and the connection plate 80. An outlet 152 is formed in the portion surrounded by the upper half portion 122 and the connection plate 80. Both the inlet 151 and the outlet 152 are substantially rectangular in a horizontal long shape in a front view.

[0043] The inlet 151 corresponds to the outlet 531 of the primary heat exchanger 5. The inlet 151 is an opening for introducing the combustion exhaust flowing out from the outlet 531 into the covering part 20. The outlet 152 corresponds to the inlet 617 of the secondary heat exchanger 6. The outlet 152 is an opening for guiding the combustion exhaust that has passed through the covering part 20 toward the inlet 617.

[0044] Note that the depth of the recess 26 is substantially the same as the plate thickness of each of the right fixing part 82 and the left fixing part 83 of the connection plate 80. Therefore, as shown in FIG. 13, the step between the front surfaces of the right fixing part 82 and the left fixing part 83 and the front surface of the flange part 22 can be reduced. Inside each recess 26, a sealing material 200 is applied to the gap Q generated on the outer periphery of each of the right fixing part 82 and the left fixing part 83. Thereby, the inside of each recess 26 is horizontally filled by the right fixing part 82 or the left fixing part 83 and the sealing material 200, so that the step with the front surface of the flange part 22 can be made smaller.

[0045] Next, as shown in FIG. 12, the packing 90 is adhered to the flange part 22 of the covering part 20 to which the rectifying plate 70 and the connection plate 80 are fixed with an adhesive from the front. As shown in FIG. 14, the frame-shaped part 91 of the packing 90 is adhered to the front surface of the flange part 22. The plate-shaped part 92 of the packing 90 is adhered to the front surface of the connection plate 80. At this time, the right end part of the frame-shaped part 91 abuts against the left surface of the rib 821 of the right fixing part 82 of the connection plate 80, and the left end part of the frame-shaped part 91 abuts against the right surface of the rib 831 of the left fixing part 83 of the connection plate 80. The upper end part of the plate-shaped part 92 abuts against the lower surface of the rib 811 at the upper end part of the main body part 81 of the connection plate 80, and the lower end part of the plate-shaped part 92 abuts against the lower surface of the rib 812 at the lower end part of the main body part 81 of the connection plate 80. Thereby, the packing 90 can be prevented from being displaced with respect to the flange part 22 of the covering part 20 and the connection plate 80. In this way, the path unit 7 is completed.

[0046] Then, as shown in FIG. 6, the completed path unit 7 is pressed 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 from the rear. At this time, the lower half 121 (see FIG. 12) of the flange portion 22 of the covering portion 20 abuts against the rear surface of the rear wall 530 of the primary heat exchanger 5 via the packing 90, on the right side, left side, and lower side of the outlet 531. 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 via the packing 90, on the right side, left side, and upper side of the inlet 617. The front surface of the connection plate 80 abuts against the boundary portion 101. The boundary portion 101 is a portion between the outlet 531 and the inlet 617. The inlet 151 provided on the lower side of the front surface of the covering portion 20 is disposed opposite to the outlet 531 of the primary heat exchanger 5, and the outlet 152 provided on the upper side of the front surface is disposed opposite to the inlet 617 of the secondary heat exchanger 6.

[0047] The ten fixing holes 24 provided in the flange portion 22 are respectively arranged in 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 via the ten fixing holes 95 provided in the packing 90. Ten screws 45 are inserted into the ten fixing holes 24 provided in the flange portion 22 from the rear and fastened to the five fixing holes 58 and the five fixing holes 68 respectively via the ten fixing holes 95 of the packing 90. Thereby, the path unit 7 is fixed stably and firmly so as to cover the rear walls 530 and 614 of the primary heat exchanger 5 and the secondary heat exchanger 6 from the rear (see FIG. 3).

[0048] As shown in FIGS. 4 and 5, within the covering portion 20, the rectifying plate 70 is supported at a position spaced forward from the front surface of the rear wall 211 of the bulging portion 21. The main body portion 71 of the rectifying plate 70 divides the space within the covering portion 20 into front and rear parts. Thereby, the combustion exhaust is positively introduced into the front side portion of the internal space of the covering portion 20. Therefore, it is possible to prevent the generation of a vortex of the combustion exhaust in the internal space of the covering portion 20, and thus it is possible to prevent the occurrence of a pressure loss.

[0049] And in this embodiment, among the path units 7, the main part through which the combustion exhaust passes from the outlet 531 toward the inlet 617 can be composed of two extremely simple and few parts, namely the covering part 20 and the connection plate 80. Thereby, in this embodiment, the assembly of the path unit 7 can be facilitated, so that the productivity of the water heater 1 can be improved and the cost can also be saved.

[0050] Also, the fixing plate 31, the rectifying plate 70, and the fixing plate 32 are fixed to the front surface of the rear wall 211 of the bulging part 21 of the covering part 20, and the connection plate 80 is fixed to the fixing plate 32. Thereby, the water heater 1 can effectively act the tightening force of the screw 45 on the packing 90 located behind the boundary part 101 through the bulging part 21, the fixing plate 31, the rectifying plate 70, and the fixing plate 32. Thereby, the water heater 1 can preferably crush the packing 90, so that the path unit 7 can be closely attached to the peripheral parts of the outlet 531 and the inlet 617 respectively, and the boundary part 101 between the outlet 531 and the inlet 617. Therefore, although the water heater 1 has a simple structure, it can prevent the leakage of the combustion exhaust.

[0051] Also, since the outlet 531 and the inlet 617 are rectangular in shape that is longer in the left - right direction than in the up - down direction, among the boundary part 101 between them, the central part in the left - right direction where leakage is likely to occur can be indirectly suppressed by the connection plate 80 via the packing 90, so that good sealing can be achieved.

[0052] The connection plate 80 is fixed to the front surface of the flange part 22 of the covering part 20 at a position sandwiching the bulging part 21 in the center. Thereby, the water heater 1 can act the stress of the tightening of the screw 45 on the boundary part 101 more directly and uniformly. Thereby, the water heater 1 can further improve the sealing performance of the covering part 20.

[0053] Since the depths of the recesses 26 provided on both the left and right sides of the flange portion 22 are substantially the same as the respective plate thicknesses of the right fixing portion 82 and the left fixing portion 83 of the connection plate 80, 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. Thereby, since the packing 90 can be brought into close contact with the front surface of the flange portion 22, the sealing performance of the covering portion 20 can be further improved.

[0054] On the front surface of the connection plate 80, two protruding portions 84 are provided. The protruding portions 84 protrude forward and extend parallel to the length direction of the boundary portion 101. Thereby, the water heater 1 can more suitably crush the packing 90 corresponding to the boundary portion 101, so that the sealing performance of the covering portion 20 can be further improved.

[0055] In the above description, the exhaust hood 53 outlet 531 is an example of the "outlet portion" of the present invention, the inlet 617 is an example of the "inlet portion" of the present invention. The path unit 7 is an example of the "path member" of the present invention. The covering portion 20 is an example of the "main body portion" of the present invention. The connection plate 80 is an example of the "erection portion" of the present invention. Further, the "sensible heat recovery portion" of the present invention is a portion that recovers the sensible heat in the combustion exhaust gas, and in the present embodiment in the specification, it is a concept including 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 the latent heat in the combustion exhaust gas, and in the present embodiment in the specification, it is a concept including the secondary heat exchanger 6.

[0056] As described above, the water heater 1 of the present 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 a plurality of rich-lean burners housed in the combustion device 4. The primary heat exchanger 5 includes a peripheral wall 51 and an exhaust hood 53. A plurality of heat transfer tubes 52 extending in the left-right direction are housed within the peripheral wall 51. The primary heat exchanger 5 performs heat exchange between the sensible heat of the combustion exhaust flowing within the peripheral wall 51 and the exhaust hood 53 and the water flowing within the heat transfer tubes 52. The secondary heat exchanger 6 is provided downstream of the combustion exhaust path and adjacent above the primary heat exchanger 5. The secondary heat exchanger 6 includes a housing 61. A plurality of heat transfer tubes 62 extending in the left-right direction are housed within the housing 61. The secondary heat exchanger 6 performs heat exchange between the latent heat of the combustion exhaust flowing within the housing 61 and the water flowing within the heat transfer tubes 62. An outlet 531 opening rearward is provided on the rear wall 530 of the exhaust hood 53 of the primary heat exchanger 5. An inlet 617 opening rearward is provided on the rear wall 614 of the housing 61 of the secondary heat exchanger 6.

[0057] The path unit 7 is fixed from the rear so as to cover these outlet 531 and inlet 617. The path unit 7 guides the combustion exhaust discharged from the outlet 531 into the housing 61 through the inlet 617. The path unit 7 includes a covering portion 20 and a connection plate 80. The covering portion 20 includes a bulging portion 21 and a flange portion 22. The bulging portion 21 bulges rearward. The flange portion 22 extends vertical in the left-right direction from the front end portion of the bulging portion 21. The connection plate 80 is installed between both left and right side portions of the flange portion 22 so as to have a predetermined gap in the front-rear direction from the rear wall 211 of the bulging portion. The connection plate 80 and the flange portion 22 are in contact with the peripheral portions of the outlet 531 and the inlet 617 respectively via a packing 90.

[0058] In the portion surrounded by the connection plate 80 and the lower half 121 of the flange portion 22, an inlet 151 is formed. The lower half 121 is the portion below the connection plate 80 on the front surface of the flange portion 22. The inlet 151 overlaps the outlet 531 from the rear and introduces the combustion exhaust in the exhaust hood 53 into the covering portion 20. In the portion surrounded by the connection plate 80 and the upper half 122 of the flange portion 22, an outlet 152 is formed. The upper half 122 is the portion above the connection plate 80 on the front surface of the flange portion 22. The outlet 152 overlaps the inlet 617 from the rear and leads out the combustion exhaust in the covering portion 20 into the housing 61 of the secondary heat exchanger 6. Thus, the water heater 1 can constitute the main part of the path unit 7 with extremely simple and few components, namely the covering portion 20 and the connection plate 80. Thereby, in this embodiment, the path unit 7 can be easily assembled, so that the productivity of the water heater 1 can be improved and the cost can also be saved.

[0059] Note that the present invention is not limited to the above embodiment, and various modifications are possible. Although the peripheral wall 51 of the primary heat exchanger 5 and the exhaust hood 53 are separate bodies, they may be integrated. The shapes of the outlet 531 and the inlet 617 do not have to be rectangular. The flange portion 22 of the covering portion 20 is fastened to the rear walls 530, 614 with ten screws 45, but the number of the screws 45 and the fastening positions are not limited to the above embodiment. The number of the heat transfer tubes 52, 62 extending in the left - right direction is also not limited. Among the path unit 7, the fixing plates 31, 32 and the rectifying plate 70 may be omitted. When the rectifying plate 70 is omitted, the fixing plates 31 and 32 may be integrated and abutted against the rear surface of the connection plate 80. The packing 90 may also be omitted, but in order to make the covering portion 20 and the connection plate 80 closely contact with the respective rear walls 530, 614 of the primary heat exchanger 5 and the secondary heat exchanger 6, it is desirable to abut them via the packing 90.

[0060] Also, the method for assembling the path unit 7 is not limited to the above embodiment. In the above embodiment, the fixing plates 31 and 32 are fixed before and after the rectifying plate 70, and further, the connecting plate 80 fixed to the front side is fixed to the front side of the covering portion 20. However, the order of fixing each member may be changed. For example, after fixing the fixing plates 31 and 32 before and after the rectifying plate 70 to the inside of the covering portion 20, the connecting plate 80 may be fixed from the front side.

[0061] In addition, the water heater 1 includes the secondary heat exchanger 6 adjacent above the primary heat exchanger 5. However, for example, as shown in FIG. 15, it may be a sensible heat recovery type water heater including an exhaust box 600 instead of the secondary heat exchanger 6. The exhaust box 600 is provided adjacent above 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 portion" of the present invention. The exhaust box 600 is a substantially box shape 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 flowing from the path unit 7 and discharges it to the outside from the exhaust portion 63. The exhaust box 600 is an example of the "discharge portion" of the present invention. In the case of this configuration, the rectifying plate 70 (see FIG. 5) in the path unit 7 may be omitted, and it is preferable to use one fixing member 300 in which the fixing plates 31 and 32 are integrated. Even in such a modification, the same effects as those of the above embodiment can be obtained.

Explanation of Reference Numerals

[0062] 1 Water heater 5 Primary heat exchanger 6 Secondary heat exchanger 7 Path unit 20 Covering portion 21 Bulging portion 22 Flange portion 53 Exhaust hood 80 Connecting plate 121 Lower side portion 122 Upper side portion 500 Heat exchanger 530 Rear wall 531 Outlet 600 Exhaust box 614 Rear wall 617 Inlet

Claims

1. A sensible heat recovery unit provided upstream of an exhaust path through which combustion exhaust of a burner flows, for exchanging sensible heat of the combustion exhaust and passing water; A latent heat recovery unit provided downstream of the exhaust path and above the sensible heat recovery unit, for exchanging latent heat of the combustion exhaust that has passed through the sensible heat recovery unit and passing water; A path member that connects an outlet portion provided at the rear of the sensible heat recovery unit and opening rearward, and an inlet portion provided at the rear of the latent heat recovery unit and opening rearward, and guides the combustion exhaust discharged from the outlet portion into the latent heat recovery unit through the inlet portion; Comprising; The path member is; A main body portion including a bulging portion bulging rearward, and a flange portion protruding in a flange shape outward from the front end portion of the bulging portion and expanding in the vertical and horizontal directions; A bridging portion bridged between both left and right side portions of the flange portion so as to provide a predetermined gap in the front-rear direction from the rear wall of the bulging portion; Comprising; The bridging portion and the flange portion are in contact with respective peripheral portions of the outlet portion and the inlet portion; A leading-in port for introducing the combustion exhaust in the sensible heat recovery unit into the path member, overlapping the outlet portion from the rear, is formed in a portion surrounded by the bridging portion and a lower half portion of the flange portion which is a portion below the bridging portion of the flange portion; A leading-out port for leading out the combustion exhaust in the path member into the latent heat recovery unit, overlapping the inlet portion from the rear, is formed in a portion surrounded by the bridging portion and an upper half portion of the flange portion which is a portion above the bridging portion of the flange portion; A water heater characterized by the above.

2. A sensible heat recovery unit provided upstream of an exhaust path through which combustion exhaust of a burner flows, for exchanging sensible heat of the combustion exhaust and passing water; A discharge portion provided downstream of the exhaust path and above the sensible heat recovery unit, for receiving the combustion exhaust that has passed through the sensible heat recovery unit and discharging it to the outside; A path member that connects an outlet portion provided at the rear of the sensible heat recovery unit and opening rearward, and an inlet portion provided at the rear of the discharge portion and opening rearward, and guides the combustion exhaust discharged from the outlet portion into the discharge portion through the inlet portion; Comprising; The path member is; A main body portion including a bulging portion bulging rearward, and a flange portion protruding in a flange shape outward from the front end portion of the bulging portion and expanding in the vertical and horizontal directions; A bridging portion bridged between both left and right side portions of the flange portion so as to provide a predetermined gap in the front-rear direction from the rear wall of the bulging portion; Comprising; The installation part and the flange part are in contact with the peripheral parts of the outlet part and the inlet part respectively, In a portion surrounded by the installation part and the lower half part which is the part of the flange part below the installation part, an inlet is formed which overlaps the outlet part from the rear and introduces the combustion exhaust gas in the sensible heat recovery part into the path member. In a portion surrounded by the installation part and the upper half part which is the part of the flange part above the installation part, an outlet is formed which overlaps the inlet part from the rear and leads the combustion exhaust gas in the path member into the discharge part. A water heater characterized by the above.

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