JP7653145B2 - 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 exhaust path of the burner, 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.

In a latent heat recovery water heater, for example, it is possible to have both the outlet of the primary heat exchanger and the inlet of the secondary heat exchanger open toward the rear, and to connect these inlets and outlets with a pathway member. The pathway member extends vertically, with its lower opening connected to the outlet of the primary heat exchanger and its upper opening connected to the inlet of the secondary heat exchanger. The combustion exhaust gas that passes through the primary heat exchanger flows through the pathway member via the outlet and is led out from the inlet into the secondary heat exchanger.

JP 2020-67220 A

In a water heater with the above configuration, the outlet of the primary heat exchanger is open toward the rear, so the combustion exhaust gas flowing out from the outlet flows toward the rear surface of the pathway member. As a result, a mainstream of the combustion exhaust gas is formed along the rear surface of the pathway member, and a vortex of the combustion exhaust gas is generated in the front part of the mainstream, which can cause pressure loss within the pathway member.

In addition, because the inlet of the secondary heat exchanger is also open toward the rear, the combustion exhaust gas is biased toward the front when it is introduced into the secondary heat exchanger, but due to the inertia of the gas as it flows through the path member and the amount of heat it retains, it tends to flow upwards and not downwards. This makes it difficult for the combustion exhaust gas to hit the heat transfer tubes located upstream and below among the heat transfer tubes in the secondary heat exchanger, which can result in inefficient heat exchange.

The object of the present invention is to provide a water heater that can exchange heat efficiently.

The water heater of claim 1 comprises a sensible heat recovery section provided upstream of an exhaust path through which the combustion exhaust gas from a burner flows, for exchanging heat between the 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 the latent heat of the combustion exhaust gas that has passed through the sensible heat recovery section and water passing through the exhaust gas; an outlet section provided at the rear of the sensible heat recovery section and opening toward the rear; and an inlet section provided at the rear of the latent heat recovery section and opening toward the rear. The exhaust gas discharged from the outlet section is connected to an inlet section provided at the rear of the latent heat recovery section, and a path for leading the combustion exhaust gas discharged from the outlet section into the latent heat recovery section via the inlet section. and a straightening member that is provided within the pathway member, divides the internal space of the pathway member, and straightens the combustion exhaust gas flowing through the internal space. The pathway member has a main body portion that extends in the vertical direction, a lower connection port that is provided at the bottom of the main body portion and connects to the outlet portion, and an upper connection port that is provided at the top of the main body portion and connects to the inlet portion. The central portion of the straightening member that corresponds to the main body portion divides the internal space of the main body portion into front and rear, and the downstream portion of the straightening member that corresponds to the upper connection port divides the internal space of the upper portion into top and bottom.

The straightening member of the water heater of claim 2 may be formed in a plate shape, the central portion may extend in the vertical direction, and the downstream portion may be bent forward from the upper end of the central portion and extend forward.

The upstream portion of the straightening member of the water heater of claim 3 that corresponds to the lower connection port may divide the lower internal space into upper and lower portions.

According to the water heater of claim 1, the central part of the straightening member divides the internal space of the main body part of the path member into front and rear parts, so that the combustion exhaust gas is actively introduced into the front part of the internal space of the main body part. This prevents the generation of a vortex of the combustion exhaust gas in the internal space of the main body part, so that pressure loss can be prevented. In addition, since the internal space of the upper part of the path member is divided into upper and lower parts by the downstream part of the straightening member, a first combustion exhaust gas flow that flows in the upper area of the latent heat recovery part and a second combustion exhaust gas flow that flows below the first combustion exhaust gas flow, with the downstream part of the straightening member as the boundary, are formed. The second combustion exhaust gas flow is prevented from flowing upward by the first combustion exhaust gas, so that it is easy to flow downward. As a result, the combustion exhaust gas is easy to flow to the upstream and lower areas of the latent heat recovery part, so that heat exchange with the water in this area can be efficiently performed. This allows the water heater to improve the thermal efficiency of the latent heat recovery part. The latent heat recovery section recovers latent heat from the combustion exhaust, but if there is any 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 vector of the second combustion exhaust gas is directed forward, so that the second combustion exhaust gas is less likely to flow to the upper part of the secondary heat exchanger. Therefore, the combustion exhaust gas is more likely to flow to the upstream and lower part of the second casing, so that the thermal efficiency of the latent heat recovery section can be further improved.

According to the water heater of claim 3, the combustion exhaust air flowing from the outlet of the sensible heat recovery section toward the lower connection port is divided into upper and lower parts, so that the upper part of the combustion exhaust air can be efficiently introduced into the front part of the internal space of the main body.

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 from diagonally forward right. FIG. 13 is a diagram showing a simulation of the flow of combustion exhaust gas when the baffle plate is omitted from within the cover portion 20. FIG. 13 is a diagram showing a simulation of the flow of combustion exhaust gas when a straightening plate 70 is arranged inside the cover portion 20. 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. The right wall 511 is provided with an inlet 55. The left wall 512 is provided with an outlet 56. 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 of 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 positioned 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 portion 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 portion 20 will be described. The cover portion 20 forms a space inside through which the combustion exhaust gas flows. The cover portion 20 is formed of a metal plate having a generally rectangular shape when viewed from the back, and includes a bulging portion 21 and a flange portion 22. The bulging portion 21 is formed in a generally box-like shape with a front opening and a generally rectangular central portion bulging rearward when viewed from the front, excluding the outer peripheral edge portion. The bulging portion 21 includes a rear wall portion 211 and a peripheral wall portion 212. The rear wall portion 211 is generally rectangular when viewed from the front. The peripheral wall portion 212 protrudes forward from the outer periphery of the rear wall portion 211. The connection portion between the outer periphery of the rear wall portion 211 and the peripheral wall portion 212 is bent in a generally arc-shaped cross section. The peripheral wall portion 212 is generally rectangular tubular and penetrates in the front-rear direction. The flange portion 22 protrudes outward from the front opening end of the peripheral wall portion 212 in a flange-like shape, and is formed in 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 portion 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 central portion 71, a lower bent portion 72, and an upper bent portion 73. The central portion 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 lower part of the right end of the back surface of the central portion 71. The protrusion 711 protrudes backward. A protrusion 712 (see FIG. 7) is provided at the upper part of the right end of the front surface of the central 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 central portion 71. The protrusion 713 protrudes backward. A protrusion 714 (see FIG. 7) is provided at the lower part of the left end of the front surface of the central portion 71.

A fixed piece 74 is provided at the right end of the central portion 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, and extends forward from the center of the right end of the central portion 71, with the tip side bending to the right. A protrusion 78 protruding forward is provided at the upper part of the front surface of the tip portion 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 central portion 71, with the tip side bending to the left. A protrusion 79 protruding forward is provided at the lower part of the front surface of the tip portion 751 of the fixed piece 75 extending to the left. The lower bent portion 72 is bent forward from the lower end of the central portion 71 in a roughly arc-like shape in side view. The upper bent portion 73 bends forward from the upper end of the central 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 central 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 portion 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 toward the lower side 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 toward the upper side 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 bridge 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 bridge 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 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 bridge portion 92, and a lower opening 94 is formed on the lower side of the bridge 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 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 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 of the part when it is housed in the water heater 1. First, as shown in FIG. 7 and FIG. 8, the assembly worker places the fixing plate 31 on the back side of the center part 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 center part 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 center part 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 center part 71 to position it.

In this state, the overlapping portion W1 (see FIG. 9) of the first fixing portion 36 and the central portion 71 is sandwiched from the front-rear direction by a pair of electrode lobes (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W1 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 central portion 71. Furthermore, the overlapping portion W2 of the second fixing portion 37 and the central portion 71 is sandwiched from the front-rear direction by a pair of electrode lobes (not shown) of a spot welding machine, and spot welding is performed. The overlapping portion W2 is a 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 central portion 71. As a result, the fixing plate 31 is fixed to the back surface of the central portion 71 (see FIG. 9).

Then, the fixing plate 32 is placed on the front side of the central portion 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-to-back directions. The first fixing portion 36 and the second fixing portion 37 are each abutted against the front side of the central 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 the protrusion 712 provided on the upper part of the right end side of the front side of the central portion 71 to position it. Furthermore, 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 the protrusion 714 provided on the lower part of the left end side of the front side of the central portion 71 to position it.

In this state, the overlapping portion W3 (see FIG. 10) of the first fixing portion 36 and the central portion 71 of the fixing plate 32 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 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 central portion 71. Furthermore, the overlapping portion W4 of the second fixing portion 37 and the central portion 71 of the fixing plate 32 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 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 central portion 71. As a result, the fixing plate 32 is fixed to the front of the central 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 central portion 71, and then fix the fixed plate 31 to the front surface of the central portion 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 portions 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 central portion 71 of the rectifying plate 70, the first and second fixed portions 36 and 37 are arranged so that they are upside down and upside down through the central portion 71. As a result, when the rectifying plate 70 is seen through from the front side to the rear, the overlapping portions W3 and W4 of the fixed plate 32 and the central portion 71 do not overlap with the overlapping portions W1 and W2 of the fixed plate 31 and the central portion 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 on the front side 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 on the front side 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 side 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 side 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 portion 20. The back surface of the center portion 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 portion 211 of the cover portion 20. A pair of left and right holes 351 provided in the center portion 35 are positioned relative to a pair of left and right protrusions 23 provided on the front surface of the rear wall portion 211, and spot welding is performed. As a result, the straightening plate 70 is fixed to the front surface of the rear wall portion 211 of the cover portion 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).

A communication port 151 is formed on the lower side of the connection plate 80, and a communication port 152 is formed on the upper side of the connection plate 80. The communication ports 151, 152 are generally rectangular and horizontally long when viewed from the front. The communication port 151 corresponds to the outlet 531 of the primary heat exchanger 5. The communication port 151 is an opening for taking in the exhaust gas from the outlet 531 into the cover 20. The communication port 152 corresponds to the inlet 617 of the secondary heat exchanger 6. The communication port 152 is an opening for allowing the exhaust gas that has passed through the cover 20 to flow into 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 bridge 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 bridge 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 bridge 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.

Then, as shown in FIG. 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. The front surface of the flange portion 22 contacts the right side, left side, and lower side of the outlet 531 in the rear wall 530 of the primary heat exchanger 5 and the right side, left side, and upper side of the inlet 617 in the rear wall 614 of the secondary heat exchanger 6, respectively, via the frame portion 91 of the packing 90. The front surface of the connection plate 80 contacts the boundary portion 101 between the outlet 531 and the inlet 617, via the bridge portion 92 of the packing 90.

The ten fixing holes 24 provided in the flange portion 22 are 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 through the ten fixing holes 95 provided in the packing 90. 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).

15 and 16, the effect of straightening the combustion exhaust gas in the cover part 20 by the straightening plate 70 will be described. First, referring to FIG. 15, the flow of the combustion exhaust gas in the cover part 20 where the straightening plate 70 is not provided will be described. FIG. 15 is a diagram simulating the flow of the combustion exhaust gas in the cover part 20 where the straightening plate 70 is not provided. The combustion exhaust gas that passes upward through the peripheral wall 51 of the primary heat exchanger 5 flows into the exhaust hood 53. The combustion exhaust gas that flows into the exhaust hood 53 flows into the cover part 20 through the outlet 531 provided in the rear wall 530 and the communication port 151 of the cover part 20. Since the outlet 531 is opened toward the rear, the combustion exhaust gas that flows out from the outlet 531 flows diagonally upward toward the front surface of the rear wall part 211 of the cover part 20. As a result, a main stream of the exhaust gas (see arrow A1) is formed along the front surface of the rear wall 211, and a vortex of the exhaust gas (see the area surrounded by the two-dot chain circle P1) is generated in the front part of the main stream. This causes a pressure loss inside the cover 20.

The exhaust gas rises along the front surface of the rear wall 211, and by moving along the peripheral wall 212, the flow shifts forward toward the upper communication port 152. The exhaust gas flows out of the communication port 152 and flows into the housing 61 of the secondary heat exchanger 6 from the inlet 617. Here, since the inlet 617 is also open toward the rear, the exhaust gas is deflected toward the front when it flows into the housing 61. However, the exhaust gas passing through the inlet 617 is subject to the upward inertia caused by the flow through the cover 20 and tends to flow upward due to the heat it holds (see arrow A2), so it tends to flow less downward. For this reason, the exhaust gas is less likely to come into contact with the heat transfer tube 62A arranged upstream and below among the multiple heat transfer tubes 62 in the housing 61.

Next, referring to FIG. 16, the flow of the combustion exhaust gas in the cover part 20 provided with the straightening plate 70 will be described. FIG. 16 is a diagram simulating the flow of the combustion exhaust gas in the cover part 20 provided with the straightening plate 70. The straightening plate 70 is supported at a position spaced forward from the front surface of the rear wall part 211 of the bulging part 21. The central part 71 of the straightening plate 70 divides the internal space in the bulging part 21 of the cover part 20 into front and rear. The lower bent part 72 divides the internal space of the communication port 151 formed in the lower part of the front surface of the cover part 20 into upper and lower parts. The upper bent part 73 divides the internal space of the communication port 152 formed in the upper part of the front surface of the cover part 20 into upper and lower parts. As a result, a first flow path 201 and a second flow path 202 are formed in the cover part 20, with the straightening plate 70 as a boundary. The first flow path 201 is located in front of the straightening plate 70, and the second flow path 202 is located behind the straightening plate 70.

The combustion exhaust gas that flows into the exhaust hood 53 of the primary heat exchanger 5 flows into the cover 20 through the outlet 531 provided in the rear wall 530 and the communication port 151 of the cover 20. At this time, the combustion exhaust gas is divided approximately evenly into the top and bottom by the lower bent portion 72 of the straightening plate 70, and flows into the first flow path 201 and the second flow path 202, respectively. The combustion exhaust gas flows upward and parallel to each other along the first flow path 201 and the second flow path 202. As a result, no vortex of the combustion exhaust gas is generated in the front part of the cover 20, so the water heater 1 can prevent pressure loss from occurring within the cover 20.

Then, the combustion exhaust gas that flows upward in each of the first flow path 201 and the second flow path 202 shifts its flow forward toward the upper communication port 152 by moving along the peripheral wall portion 212 and the upper bent portion 73 of the straightening plate 70. The combustion exhaust gas flows into the housing 61 of the secondary heat exchanger 6 through the communication port 152 and the inlet 617. As described above, the upper bent portion 73 of the straightening plate 70 divides the internal space of the communication port 152 into upper and lower portions, so that a first flow B1 (hereinafter referred to as flow B1) and a second flow B2 (hereinafter referred to as flow B2) are formed near the inlet 617. Flow B1 is the flow of the combustion exhaust gas that flows above the upper bent portion 73 in the upper region inside the housing 61. Flow B2 is the flow of the combustion exhaust gas that flows below the flow B1, with the upper bent portion 73 as the boundary.

Since flow B2 is prevented from flowing upward by flow B1, it tends to flow downward. As a result, compared to the configuration of FIG. 15 that does not have the baffle plate 70, the combustion exhaust gas tends to flow toward the heat transfer tubes 62A that are located upstream and in the lower area of the housing 61. Therefore, the secondary heat exchanger 6 can efficiently exchange heat with the passing water in all of the heat transfer tubes 62, improving the thermal efficiency of the water heater 1.

The upper bent portion 73 of the straightening plate 70 extends forward while bending forward from the upper end of the central portion 71. This causes the vector of the combustion exhaust flowing through the second flow path 202 to face forward, making it difficult for the combustion exhaust of flow B2 to flow into the upper region inside the housing 61. As a result, the combustion exhaust is more likely to flow near the heat transfer tube 62A inside the housing 61, so the thermal efficiency of the secondary heat exchanger 6 of the water heater 1 can be further improved.

The lower bent portion 72 of the straightening plate 70 also bends forward and extends forward from the lower end of the central portion 71. This separates the combustion exhaust flowing from inside the exhaust hood 53 of the primary heat exchanger 5 toward the communication port 151 into upper and lower portions, and allows the combustion exhaust to be effectively guided toward each of the first flow path 201 and the second flow path 202. In particular, the combustion exhaust separated upward is guided to the first flow path 201, allowing the combustion exhaust to be actively directed toward the front portion of the cover portion 20.

In the above description, the outlet 531 is an example of the "outlet" of the present invention, and the inlet 617 is an example of the "inlet" of the present invention. The path unit 7 is an example of the "path member" of the present invention. The rear wall 211 and the left and right sides of the peripheral wall 212 of the cover 20 are an example of the "main body" of the present invention. The communication port 151 is an example of the "lower connection port" of the present invention, and the communication port 152 is an example of the "upper connection port" of the present invention. The straightening plate 70 is an example of the "straightening member" of the present invention. The lower bent portion 72 is an example of the "upstream portion" of the present invention, and the upper bent portion 73 is an example of the "downstream portion" of the present invention. In addition, the "sensible heat recovery portion" of the present invention is a portion that recovers sensible heat in the combustion exhaust gas, and in this embodiment of the specification, is a concept that includes the primary heat exchanger 5 and the exhaust hood 53. In addition, the "latent heat recovery portion" of the present invention is a portion that recovers latent heat in the combustion exhaust gas, 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 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 flowing through the heat transfer tube 52. The secondary heat exchanger 6 is provided downstream of the 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 flowing through the heat transfer tube 62. An outlet 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 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 connects the outlet 531 and the inlet 617, receives the exhaust gas discharged from the outlet 531, and directs it into the housing 61 through the inlet 617. A straightening plate 70 is provided in the path unit 7. The straightening plate 70 divides the internal space of the path unit 7 and straightens the exhaust gas flowing through the internal space.

The path unit 7 includes a cover portion 20 and communication ports 151 and 152. The cover portion 20 extends in the vertical direction. The communication port 151 is provided at the bottom of the cover portion 20 and connects to the outlet port 531. The communication port 152 is provided at the top of the cover portion 20 and connects to the inlet port 617. The center portion 71 of the straightening plate 70 corresponds to both the left and right sides of the rear wall portion 211 and the peripheral wall portion 212 of the cover portion 20, and divides the internal space into front and rear. This actively introduces the exhaust gas into the front portion of the internal space of the cover portion 20. This prevents the exhaust gas from swirling in the internal space of the cover portion 20, and therefore prevents pressure loss.

The upper bent portion 73 of the straightening plate 70 divides the internal space of the communication port 152 into upper and lower portions. This forms a first combustion exhaust flow B1 that flows through the upper region inside the housing 61 of the secondary heat exchanger 6, and a second combustion exhaust flow B2 that flows below flow B1, with the upper bent portion 73 of the straightening plate 70 as the boundary. Flow B2 is prevented from flowing upward by flow B1, so it tends to flow downward. As a result, the combustion exhaust is more likely to flow near the heat transfer tube 62A that is arranged in the upstream and lower region inside the housing 61. This allows the water heater 1 to improve the thermal efficiency of the secondary heat exchanger 6.

The present invention is not limited to the above embodiment, and various modifications are possible. The upper bent portion 73 of the straightening plate 70 bends forward from the upper end of the central portion 71 and protrudes forward, but the position of the front end of the upper bent portion 73 is not limited. For example, the front end of the upper bent portion 73 may be in the same position as the inlet 617, or may protrude forward from the inlet 617. By having the front end of the upper bent portion 73 protrude forward from the inlet 617, the flow B2 of the combustion exhaust gas can be reliably directed toward the lower region within the housing 61.

The lower bent portion 72 of the straightening plate 70 may be omitted. The position of the front end of the lower bent portion 72 is not limited, but it is preferable to position it, for example, at the same position as the communication port 151 or further rearward than the communication port 151. By positioning it in this way, the combustion exhaust gas flowing into the communication port 151 can be divided into upper and lower portions while flowing smoothly into each of the first flow path 201 and the second flow path 202.

Also, as shown in FIG. 16, the lower portion 213 of the peripheral wall portion 212 of the cover portion 20 may be formed in a tapered shape that slopes gently upward from the front end side to the rear end side. In this case, the angle between the lower portion 213 and the rear wall portion 211 becomes an obtuse angle. As a result, the combustion exhaust gas that is divided downward at the communication port 151 flows diagonally upward along the inner surface of the lower portion 213, and at the corner where the lower portion 213 and the rear wall portion 211 are connected, it can be turned gently upward and flow smoothly through the second flow path 202. Since the combustion exhaust gas flows smoothly, the heat exchange in the secondary heat exchanger 6 and the exhaust performance of the combustion exhaust gas can be improved.

The peripheral wall 51 and exhaust hood 53 of the primary heat exchanger 5 are separate bodies, but 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 cover portion 20 is fastened to the rear walls 530, 614 with ten screws 45, but the number of screws 45 and the fastening positions are not limited to the above embodiment. There is also no limit to the number of heat transfer tubes 52, 62 extending in the left-right direction.

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 fixed to the front side of the cover part 20, but the order in which each component is 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 fixed to the inside of the cover part 20, and then the connecting plate 80 may be fixed from the front side.

REFERENCE SIGNS LIST 1 water heater 5 primary heat exchanger 6 secondary heat exchanger 7 path unit 20 cover 53 exhaust hood 70 straightening plate 71 center 72 lower bent portion 73 upper bent portion 151 communication port 152 communication port 211 rear wall 212 peripheral wall 530 rear wall 531 outlet 614 rear wall 617 inlet

Claims (3)

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 latent heat of the combustion exhaust gas that has passed through the sensible heat recovery section with water;
a path member that connects an outlet portion provided at the rear of the sensible heat recovery unit and opening toward the rear, and an inlet portion provided at the rear of the latent heat recovery unit and opening toward the rear, and that guides the combustion exhaust gas discharged from the outlet portion into the latent heat recovery unit via the inlet portion;
a straightening member that is provided within the pathway member, that divides an internal space of the pathway member, and straightens the combustion exhaust gas flowing through the internal space,
The pathway member includes:
A main body portion extending in the vertical direction;
A lower connection port provided at a lower portion of the main body and connected to the outlet port;
an upper connection port provided on an upper portion of the main body and connected to the inlet port;
a central portion of the flow regulating member corresponding to the main body portion divides the internal space of the main body portion into front and rear portions;
A water heater characterized in that a downstream portion of the straightening member corresponding to the upper connection port divides the internal space of the upper portion into upper and lower portions. The flow straightening member is formed in a plate shape,
The central portion extends in a vertical direction,
The water heater according to claim 1 , wherein the downstream portion is bent forward and extends forward from an upper end of the central portion. 3. The water heater according to claim 1, wherein an upstream portion of the flow straightening member corresponding to the lower connection port divides the internal space of the lower portion into upper and lower portions.

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