water heater

Abstract

To suppress the uneven supply of air into a combustion device in a water heater.SOLUTION: A water heater 1 comprises a combustion device 3, a blower 7 and an air guide part 40. The combustion device 3 comprises a plurality of burners 140 and a case 120. The air guide part 40 comprises a plate part 42 and an air passage plate 52. The plate part 42 is arranged apart from a bottom face part 121 at a distance in a constitution for covering a plurality of hole parts 132 of the bottom face part 121 of the case 120 from below, and constituted so as to guide air into a space which is formed around itself while receiving air which is sent from the blower 7 by its own lower face 42A. The air passage plate 52 comprises a penetration hole part 54 being a flow-in port. The penetration hole part 54 is an inlet for allowing air to intrude into a second space 92 between the plate part 42 and the bottom face part 121 from a first space 91 around the plate part 42. In the water heater 1, air which intrudes into the second space 92 is introduced into the case 120 via a plurality of hole parts 132.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to water heaters. [Background technology]

[0002] Patent Document 1 discloses an example of a combustion device for a gas appliance. The combustion device in Patent Document 1 includes multiple burner units and a storage case 20 that houses the multiple burner units. The burner units are configured to introduce fuel gas and primary air through an inlet located upstream of a gas flow path, and then eject and ignite the mixture from a flame nozzle located downstream of the gas flow path, thereby forming a flame at the flame nozzle. The storage case houses multiple burner units arranged side by side with a constant spacing between them. Furthermore, the storage case is provided with a circulation path that circulates primary air from the outside air flowing in through an opening located at the bottom to the inlets of each burner unit, and a circulation path that circulates secondary air from the outside air into spaces formed between the burner units. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-027338 Summary of the Invention [Problem to be solved by the invention]

[0004] Due to space constraints, water heaters typically have a configuration in which a blower is positioned below the combustion device, facing the combustion device, and the air blown by the blower is introduced into the combustion device. However, this type of configuration can lead to uneven air supply. For example, the area near the blower, which is most susceptible to the air flow, is more susceptible to the influence of the supply air and tends to experience relatively high pressure, while areas outside the area are less susceptible to the influence of the supply air and tend to experience lower pressure, resulting in localized increases in pressure in some areas.

[0005] An object of the present disclosure is to provide a technology that can easily prevent air from being unevenly supplied to a combustion device in a water heater. [Means for solving the problem]

[0006] The water heater according to the present disclosure includes: a combustion device including a plurality of burners for burning gas and a case for accommodating the plurality of burners, the case having a bottom surface with a plurality of holes; a blower disposed below the combustion device and supplying air; a housing that houses the combustion device and the blower; a plate portion that is disposed at a distance from the bottom surface portion and that covers the plurality of holes from below, receives the air sent from the blower with its underside, and guides the air into a space around itself; an inlet through which the air flows from a first space around the plate portion to a second space between the plate portion and the bottom surface portion; and The air that has entered the second space is introduced into the case through the plurality of holes. [Effects of the Invention]

[0007] The technology disclosed herein makes it easy to prevent air from being unevenly supplied to the combustion device in a water heater. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view illustrating a water heater according to a first embodiment. [Figure 2] FIG. 2 is a front view schematically showing the configuration of the water heater of FIG. 1, with the front cover, operating devices, etc. omitted. [Figure 3] FIG. 3 is a front view that schematically shows the configuration of FIG. 2, with the gas distribution section and the like omitted. [Figure 4] FIG. 4 is a perspective view schematically showing the vicinity of a gas distribution unit in the water heater of FIG. [Figure 5] FIG. 5 is a perspective view schematically showing a heat exchanger, a combustion device, a blower, etc. in the water heater of FIG. [Figure 6] FIG. 6 is a perspective view that schematically shows the configuration of FIG. 5 with the front wall, both side walls, rear wall, etc. omitted. [Figure 7] FIG. 7 is a perspective view that schematically shows a configuration in which the air guide portion and the like are omitted from the configuration of FIG. [Figure 8] 8 is a perspective view showing a partial configuration of the combustion device, a gas distribution unit, a blower, etc. in the water heater of FIG. [Figure 9] FIG. 9 is a perspective cross-sectional view that schematically shows the configuration of FIG. 8 cut along a predetermined cutting plane. [Figure 10] FIG. 10 is a perspective cross-sectional view that schematically shows the configuration in the vicinity of the combustion device of the water heater in FIG. 1 (the configuration including the combustion device, gas distribution unit, bottom wall, blower, etc.) cut at a predetermined position. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes exemplary embodiments of the present disclosure. The exemplary features may be combined in any compatible combination.

[0010] [1] A combustion device comprising a plurality of burners for burning gas and a case for accommodating the plurality of burners, the case having a bottom surface provided with a plurality of holes; a blower disposed below the combustion device and supplying air; a housing that houses the combustion device and the blower; a plate portion that is disposed at a distance from the bottom surface portion and that covers the plurality of holes from below, receives the air sent from the blower with its underside, and guides the air into a space around itself; an inlet through which the air flows from a first space around the plate portion to a second space between the plate portion and the bottom surface portion; and The air that has entered the second space is introduced into the case through the plurality of holes. Water heater.

[0011] The water heater described in [1] above receives air sent from the blower on the underside of the plate and directs it into the space surrounding the plate, thereby preventing the air from the blower from directly entering the multiple holes. Therefore, this water heater can prevent uneven supply of air from the blower from directly entering the case. Furthermore, this water heater directs the air supplied from the blower from near the plate into the surrounding space (first space), then circulates it around the space between the plate and the bottom (second space), before introducing it into the multiple holes located on the back side (upper side) of the plate. This reduces the effect of the blower's pressure near the multiple holes, allowing air to more evenly enter the case.

[0012] [2] The blower has an air outlet for discharging the air, The air outlet and the lower surface of the plate portion are arranged to face each other vertically. The water heater described in [1].

[0013] In the water heater of the above [2], the blower can be placed closer to the bottom, so the blower and combustion device can be configured more compactly, and even with such a compact configuration, the supply air can be made uniform.

[0014] [3] A plurality of air passage plates are provided on both the front and rear sides and the left and right sides of the second space so as to partially close the gaps between the front, rear, left and right outer edge portions of the plate portion and the bottom surface portion and to surround the second space, Each of the air passage plates is provided with a plurality of through-holes, The through-hole portion is the inlet A water heater according to [1] or [2].

[0015] The water heater of [3] can introduce air into the second space through multiple air passage plates arranged on both the front and rear sides and the left and right sides of the second space. In other words, air can be introduced more evenly into the second space from the front, back, left and right sides of the second space, making it easier for air to enter the second space more evenly. Moreover, because the air flows through multiple through-holes in each air passage plate, it is possible to prevent excessive pressure concentration in certain areas even as it passes through the air passage plates. This makes it easier for air to be introduced into the case more evenly.

[0016] [4] A gas distribution unit having a plurality of nozzles for discharging the gas, the case has a front wall portion provided with a plurality of inlets, the gas distribution section is configured to cover the front wall section from the front side, the plurality of inlets are paths for introducing the gas distributed from the gas distribution unit into the case, and the gas introduced through each of the inlets is supplied to each of the burners; a third space through which the air flows is formed between the front wall portion and the gas distribution portion, A portion of the air guided by the lower surface enters the third space, The air in the third space flows into the case through the plurality of inlets. A water heater according to any one of [1] to [3].

[0017] In the water heater of [4], a portion of the air received and guided by the underside of the plate portion can be diverted to the multiple inlets via the third space. The multiple inlets are paths for introducing gas from the gas distribution section to each burner, and the presence of the plate portion allows the water heater to effectively guide the air to each inlet. Therefore, this water heater can easily supply primary air for combustion to each burner, making it easier to improve the burner's combustion performance.

[0018] First Embodiment The following description relates to the water heater 1 according to the first embodiment. 1. Overall configuration of water heater 1 Fig. 1 is a front view illustrating a water heater 1 according to the first embodiment. Fig. 2 is a front view illustrating a simplified configuration of the water heater 1 with a front cover 2A removed from a housing 2.

[0019] As shown in FIG. 2, the water heater 1 includes a housing 2, a combustion device 3, a heat exchanger 4, an exhaust section 5, a blower 7, and the like. The housing 2 is a box-shaped case made of a metal material, and includes a housing main body 2B that is open at the front and a front cover 2A (FIG. 1) that is detachable from the housing main body 2B. The front cover 2A shown in FIG. 1 closes the housing main body 2B from the front side. As shown in FIG. 2, the housing 2 houses various components, such as the combustion device 3, the heat exchanger 4, the exhaust section 5, and the blower 7. The combustion device 3 is located near the center inside the housing 2. The heat exchanger 4 is located above the combustion device 3 inside the housing 2. The exhaust section 5 is located above the heat exchanger 4 inside the housing 2. The gas distribution section 10 is located between the combustion device 3 and the front cover 2A. The blower 7 is located below the combustion device 3 inside the housing 2.

[0020] In this specification, the longitudinal direction of the rectangular front cover 2A is the up-down direction, and the vertical direction when the water heater 1 is installed is the up-down direction. The direction in which both side wall portions provided on both the left and right sides of the housing main body 2B extend is the up-down direction. The short-side direction of the front cover 2A is the left-right direction, and the direction perpendicular to the up-down direction and the left-right direction is the front-rear direction. In the example shown in FIG. 1, the direction perpendicular to the largest flat surface on the front of the front cover 2A is the front-rear direction. In the example shown in FIG. 2 etc., the motor shaft of the blower 7 is configured to rotate around a rotation axis, and the direction of this rotation axis is the front-rear direction. In addition, the thickness direction (plate thickness direction) of the portion (plate-shaped portion) of the front wall portion 124 where the inlet 125 is formed is the front-rear direction. The direction in which the multiple upper inlets 125A are arranged is the left-right direction, and the direction in which the multiple lower inlets 125B are arranged is also the left-right direction. The direction in which the multiple burners 140 are arranged is also the left-right direction.

[0021] The combustion device 3 shown in Figures 2 and 3 is a device that combusts gas (fuel gas) supplied via the gas distribution unit 10. The combustion device 3 includes a case 120 and a burner group. The case 120 is a square box-shaped case that fits inside the housing 2. The burner group is made up of burners 140, which are flat, light- and heavy-duty burners, arranged side by side in the left-right direction. A discharge electrode for ignition, a flame rod for flame detection, and the like are provided on the upper front surface of the case 120. Details of the combustion device 3 will be described later.

[0022] The heat exchanger 4 shown in Figures 2 and 3 is a device to which combustion exhaust gas resulting from the combustion of gas in the combustion device 3 is supplied. The heat exchanger 4 includes a metal casing 4A that forms the outer shell of the heat exchanger 4, and a heat transfer tube that is at least partially housed inside the casing 4A. The heat exchanger 4 introduces the combustion exhaust gas discharged from the combustion device 3 and passes it through its interior, where heat is exchanged between the combustion exhaust gas and water flowing inside the heat transfer tube, thereby heating the water inside the heat transfer tube. The combustion exhaust gas that has passed through the heat exchanger 4 is discharged to the exhaust section 5.

[0023] 2 and 3 includes an exhaust unit main body 5A and an exhaust pipe 110. The exhaust unit main body 5A is a flow path that guides the combustion exhaust gas discharged from the heat exchanger 4 upward, and is configured as a case body made of, for example, a metal material. The exhaust pipe 110 is disposed so as to straddle the inside and outside of the exhaust unit main body 5A, and functions as a flow path that discharges the combustion exhaust gas inside the exhaust unit main body 5A to the outside of the water heater 1.

[0024] The blower 7 shown in FIGS. 2 and 3 is a fan that supplies combustion air. The blower 7 includes a drive unit having a motor, blades, etc., and an air outlet 162 (FIGS. 8 and 9) that is an opening for supplying combustion air. The air outlet 162 is located below the combustion device 3. The blower 7 is configured such that, for example, when the drive shaft of a motor (not shown) rotates, multiple blades that are linked to the drive shaft rotate, and the rotation of the multiple blades creates an air flow that forcibly flows air toward the upper side (combustion device 3 side). Note that the configuration of the blower 7 illustrated here is merely one example, and any known fan with a variety of configurations can be used as long as it is configured to forcibly supply air from the air outlet 162.

[0025] As shown in FIG. 2, water heater 1 is provided with a gas inlet 191 to which an external gas pipe is connected, a water inlet 192 to which a water pipe is connected, and a hot water outlet 193 on the underside of casing 2. Water inlet 192 is an inlet through which water is introduced from a water pipe provided outside water heater 1. Water introduced into water inlet 192 is supplied to heat transfer tubes of heat exchanger 4 via water supply pipe 115. FIG. 2 shows a portion of water supply pipe 115. Hot water outlet 193 is a hot water outlet that discharges hot water to the outside of water heater 1. Hot water introduced by the heat transfer tubes of heat exchanger 4 is discharged from hot water outlet 193 via hot water outlet pipe 116 connected to the downstream end of the heat transfer tube.

[0026] 2, gas inlet 191 is an inlet through which gas is introduced from a gas pipe provided outside water heater 1. The gas introduced into gas inlet 191 is supplied into gas distribution unit 10 via gas supply unit 114 equipped with a main valve, a proportional valve, etc.

[0027] 2. Detailed configuration of the gas distribution unit 10 and the combustion device 3 The gas distribution unit 10 is a flat gas distribution unit. The gas distribution unit 10 shown in FIG. 4 and other figures is a flow path that divides fuel gas introduced into the gas distribution unit 10 via the gas supply unit 114 and releases the fuel gas into the combustion device 3 via a nozzle 34. The gas distribution unit 10 is configured to cover an inlet 125 provided in a front wall 124 of the case 120 and is attached to the underside of the front wall 124 of the case 120. As shown in FIG. 10 , the gas distribution unit 10 includes a plate-shaped first blocking member 11, a plate-shaped second blocking member 12, and a sheet-shaped packing member 13. The second blocking member 12 shown in FIG. 2 overlaps the first blocking member 11 from the front so as to cover the first blocking member 11 from the front, with the packing member 13 sandwiched between them, so that the first blocking member 11, the second blocking member 12, and the packing member 13 are arranged to overlap each other from the front to the rear. A gas flow path 18 through which fuel gas flows is provided inside the gas distribution unit 10. The first closing member 11 includes a plurality of inlets (not shown) for introducing fuel gas from a gas supply unit 114, and a plurality of nozzles 34, and the gas flow path 18 is configured as a flow path that guides gas from the inlets to the plurality of nozzles 34.

[0028] As shown in FIGS. 4 and 10 , the plurality of nozzles 34 includes a plurality of upper nozzles 34A and a plurality of lower nozzles 34B. The plurality of upper nozzles 34A are arranged side by side in the left-right direction. The plurality of lower nozzles 34B are arranged side by side in the left-right direction. Nozzle pairs 33, each consisting of one upper nozzle 34A and one lower nozzle 34B arranged vertically, are arranged side by side in the left-right direction. Each nozzle pair 33 is arranged corresponding to a burner 140 (high- and low-concentration burner) shown in FIG. 8 and other figures. In other words, gas supplied from one nozzle pair 33 is supplied to one burner 140 arranged in the direction (rearward) of the nozzle pair 33. Gas supplied from the upper nozzle 34A is supplied into the burner 140 from an inlet 142 on the upper side of the burner 140. The gas supplied from the lower nozzle 34B is supplied into the burner 140 from an inlet 144 on the lower side of the burner 140. Note that, in Figures 8 to 10, only some of the burners 140 out of the multiple burners 140 provided in the combustion device 3 are shown, and the other burners 140 are not shown.

[0029] As shown in Figures 8 to 10, the combustion device 3 has a case 120 with multiple burners 140 inside. The case 120 is an inner case provided inside the housing 2 and houses the multiple burners 140. The case 120 has a front wall 124, a rear wall 128, side walls 126 and 127, and a bottom 121, which are configured in a box shape. The upper end of the case 120 is configured as an open opening. Specifically, the front wall 124 and the rear wall 128 face each other in the front-rear direction, and the side wall 126 and the side wall 127 face each other in the left-right direction, which form the front, rear, left, and right peripheral walls integrally. The front wall 124, the rear wall 128, and the side walls 126 and 127 are configured in a plate-like shape using one or more metal plates. The upper ends of the front wall 124, rear wall 128, and side wall 126, 127 form the openings, which function as outlets for discharging the combustion exhaust gas generated within the combustion device 3 toward the heat exchanger 4.

[0030] As shown in FIGS. 3 and 10 , a plurality of inlets 125 are provided in the front wall 124 of the case 120. Each inlet 125 is a path for introducing gas distributed from the gas distribution unit 10 into the case 120. The combustion device 3 is configured so that gas introduced through each inlet 125 is supplied to each burner 140. The plurality of inlets 125 include a plurality of upper inlets 125A and a plurality of lower inlets 125B. The plurality of upper inlets 125A are arranged side by side in the left-right direction. The plurality of lower inlets 125B are arranged side by side in the left-right direction. Inlet pairs 125Z, each consisting of one upper inlet 125A and one lower inlet 125B, are arranged side by side in the left-right direction. Each inlet pair 125Z is provided corresponding to each burner 140 (light and dark burner) shown in FIG. 8 and other figures. Gas entering through one inlet pair 125Z is supplied to one adjacent burner 140 from the rear side of this inlet pair 125Z. Specifically, each inlet pair 125Z is provided corresponding to each nozzle pair 33, and in each nozzle pair 33, gas discharged through the upper nozzle 34A is introduced into the burner 140 through the upper inlet 125A adjacent to this upper nozzle 34A, and gas discharged through the lower nozzle 34B is introduced into the burner 140 through the lower inlet 125B adjacent to this lower nozzle 34B.

[0031] The bottom surface portion 121 functions as the bottom of a box-shaped space (space for burning gas) that houses multiple burners 140. The bottom surface portion 121 is formed in a plate shape using, for example, a metal plate. The multiple holes 132 are provided evenly distributed left and right so as to extend from a region near the left end of the bottom surface portion 121 to a region near the right end, and are provided evenly distributed front and rear so as to extend from a region near the front end of the bottom surface portion 121 to a region near the rear end. The multiple holes 132 are provided as through-holes that penetrate the plate-shaped bottom surface portion 121 from top to bottom. Air is configured to pass through each of the multiple holes 132.

[0032] The combustion device 3 functions to combust gas (fuel gas) supplied into the combustion device 3 via the gas distribution section 10 within the case 120. Exhaust gas (combustion exhaust gas) generated by the combustion of gas within the case 120 is discharged from an opening at the top end of the case 120, flows into the casing 4A of the heat exchanger 4, passes through the heat exchanger 4, and flows into the exhaust section 5. The exhaust gas that has flowed into the exhaust section 5 then passes through the exhaust pipe 110 and is discharged to the outside of the water heater 1.

[0033] 3.Air induction section The following description relates to the air guide portion 40 and its surrounding structure. As shown in FIG. 10 , the rear wall 128 of the combustion device 3 extends below the bottom surface 121. The side wall portions 126 and 127 also extend below the bottom surface 121. The gas distribution portion 10 is fixed to the front wall portion 124, and extends below the bottom surface 121. The gas distribution portion 10 is fixed to the front wall portion 124 with its upper end portion overlapping the front wall portion 124. The gas distribution portion 10, the side wall portions 126 and 127, and the rear wall portion 128 surround the front, rear, left, and right sides of a space below the bottom surface 121, and the bottom wall portion 129 is provided to close the lower side of this space. That is, the bottom wall portion 129 is provided to close the opening at the lower end of the peripheral wall portion formed by the gas distribution portion 10, the side wall portions 126 and 127, and the rear wall portion 128. Bottom wall portion 129 is disposed below bottom surface portion 121 at a distance from it. Bottom wall portion 129 is configured in a plate shape, with one plate surface, or upper surface, facing upward and the other plate surface, or lower surface, facing downward. Air guide portion 40, which will be described later, is provided in the space between bottom surface portion 121 and bottom wall portion 129.

[0034] In this specification, the first space 91 is a space that is below the bottom surface portion 121 and above the bottom wall portion 129, is outside the second space 92, and is out of the area directly below the plate portion 42 (a space that does not overlap vertically with the plate portion 42). The second space 92 is a space between the plate portion 42 and the bottom surface portion 121, and is surrounded on both the front and rear and left and right sides by the air passage plates 52.

[0035] As shown in FIG. 10 , the front wall 124 of the case 120 includes an upper front wall 124A and a lower front wall 124B. The upper front wall 124A and the lower front wall 124B are configured in a stepped manner such that the front surface of the lower front wall 124B is located further rearward than the front surface of the upper front wall 124A. The front surfaces of the upper front wall 124A and the lower front wall 124B both face forward. The thickness direction of the upper front wall 124A and the lower front wall 124B is the front-to-rear direction. Specifically, a plate-like bending portion 124C is provided so as to bend rearward from the lower end of the plate-like upper front wall 124A, and the lower front wall 124B is also provided so as to bend downward from the rear end of the bending portion 124C. The gas distribution section 10 is connected to the upper front wall portion 124A and is integrally formed so as to continue downward from the upper front wall portion 124A, and the plate-shaped gas distribution section 10 and the plate-shaped upper front wall portion 124A form the front wall of the unit in which the gas distribution section 10 and the combustion device 3 are integrated. The lower front wall portion 124B is disposed on the rear side of the gas distribution section 10, spaced a distance from the back surface of the gas distribution section 10. The back surface (rear surface) of the gas distribution section 10 and the front surface of the lower front wall portion 124B are disposed opposite each other, and a third space 93 is formed between the back surface (rear surface) of the gas distribution section 10 and the front surface of the lower front wall portion 124B. The third space 93 is a space through which air can flow. The third space 93 is a space that is partitioned at the front by the gas distribution unit 10, at the rear by the lower front wall 124B, at both left and right sides by the side wall 126 and the side wall 127, and at the top by the bent portion 124C. In other words, the third space 93 is a space that is surrounded at the front, rear, left and right sides and the top by the bent portion 124C, the gas distribution unit 10, the lower front wall 124B, and the side wall 126, 127, and is open at the bottom and continues to the first space 91. In the above unit, when air supplied from the blower 7 flows into the first space 91, some of the air flowing into the first space 91 flows into the third space 93.

[0036] The blower 7 is disposed below the combustion device 3 and operates to supply air from a blower port 162 provided in a blower case 161. Specifically, at least a portion of the blower port 162 faces the lower surface 42A of the plate portion 42, and the blower port 162 and the lower surface 42A are disposed facing each other vertically. The upper end of the blower 7 is fixed to the bottom wall portion 129, and an opening (not shown) formed in the bottom wall portion 129 communicates with the space inside the blower case 161. The blower port 162 is disposed facing upward. The blower port 162 communicates with an opening in the bottom wall portion 129, and the air discharged from the blower port 162 is sent upward through the opening in the bottom wall portion 129. The wind passing through the opening of bottom wall portion 129 (air from blower 7) is an upward wind, and this upward wind directly hits underside 42A of plate portion 42 provided above air outlet 162. Because there is no member between the opening of bottom wall portion 129 and underside 42A to block the wind, underside 42A directly receives the wind from the air discharged from air outlet 162.

[0037] The air guide unit 40 includes a plate 42 and an air passage plate 52. The plate 42 is configured as a flat plate and is disposed at a distance from the bottom surface 121, covering the plurality of holes 132 from below. The thickness direction of the plate 42 is, for example, the same as the thickness direction of the bottom surface 121. The upper surface of the plate 42 is disposed along the lower surface of the bottom surface 121 and is disposed parallel to the lower surface. The lower surface 42A of the plate 42 is disposed so as to cover the air outlet 162 from above. The lower surface 42A of the plate 42 receives air sent from the fan 7 and guides the air into the space around it. In other words, when the air sent from the fan 7 hits the lower surface 42A, the air is dispersed in all directions along the lower surface 42A. The air dispersed in all directions along the lower surface 42A tends to move to the first space 91 outside the area directly below the plate portion 42.

[0038] The air passing plate 52 is a portion that allows air to flow from the first space 91 to the second space 92. The air passing plates 52 are arranged on both the front and rear and on both the left and right sides of the second space 92 so as to partially block the gaps between the bottom surface portion 121 and each of the front, rear, left and right outer edge portions of the plate portion 42 and to surround the second space 92. Specifically, the air passing plate 52 has a front passing plate 52A, a rear passing plate 52B, a first passing plate 52C, and an second passing plate 52D, which are provided integrally to surround the second space 92 in an annular shape.

[0039] The front passing plate 52A rises from the front end of the plate portion 42 and partially blocks the gap between the front end of the plate portion 42 and the bottom surface 121. The rear passing plate 52B is arranged to rise from the rear end of the plate portion 42 and partially blocks the gap between the rear end of the plate portion 42 and the bottom surface 121. The one-side passing plate 52C is arranged to rise obliquely from one end of the plate portion 42 in the left-right direction and partially blocks the gap between the one end of the plate portion 42 in the left-right direction and the bottom surface 121. The other-side passing plate 52D is arranged to rise obliquely from the other end of the plate portion 42 in the left-right direction and partially blocks the gap between the other end of the plate portion 42 in the left-right direction and the bottom surface 121. A plurality of through-holes 54 are formed in each of the front passing plate 52A, the rear passing plate 52B, the one-side passing plate 52C, and the other-side passing plate 52D. The through-hole portion 54 corresponds to an example of an inlet, and functions as an inlet through which air flows from the first space 91 to the second space 92. The air that flows from the first space 91 to the second space 92 is introduced into the case 120 through the plurality of holes 132.

[0040] Within the first space 91, a region on the front side of the front passing plate 52A communicates with the third space 93. That is, the air passage partitioned front and rear by the lower front wall portion 124B and the gas distribution unit 10 communicates with the air passage partitioned front and rear by the front passing plate 52A and the gas distribution unit 10. Therefore, of the air supplied from the blower 7 and guided by the plate portion 42, a portion of the air guided to the front flows through the space between the front passing plate 52A and the gas distribution unit 10 (a portion of the first space 91) and enters the third space 93. A portion of the air flowing into the third space 93 enters the case 120 through a plurality of inlet ports 125 formed in the lower front wall portion 124B. The air thus entering acts as primary air during combustion in the burner 140.

[0041] 4.Example of effects In water heater 1, air sent from blower 7 is received by underside 42A of plate portion 42 and can be directed into the space around plate portion 42, thereby preventing air from blower 7 from directly entering multiple holes 132. Therefore, water heater 1 can prevent uneven supply of air caused by air from blower 7 directly entering case 120. Moreover, water heater 1 can guide air supplied from blower 7 from near plate portion 42 into the surrounding space (first space 91), then turn around to the space between plate portion 42 and bottom portion 121 (second space 92), and then introduce the air into multiple holes 132 arranged on the back side (upper side) of plate portion 42. Therefore, the influence of the blowing pressure of blower 7 is easily alleviated near multiple holes 132, and air is more likely to enter case 120 more uniformly.

[0042] In water heater 1, air outlet 162 and underside 42A are arranged facing each other vertically, so that blower 7 can be positioned closer to bottom surface 121. Therefore, water heater 1 can have blower 7 and combustion device 3 configured more compactly, and even with such a compact configuration, the supply air is made uniform.

[0043] The water heater 1 can introduce air into the second space 92 via multiple air passing plates 52 arranged on both the front and rear sides and on both the left and right sides of the second space 92. In other words, air can be introduced more evenly into the second space 92 from the front, rear, left and right sides of the second space 92, making it easier for the air to enter the second space 92 more evenly. Moreover, in each air passing plate 52, the air flows so as to pass through multiple through-holes 54, making it possible to prevent the pressure from becoming too concentrated in one area even as the air passes through the air passing plate 52. This makes it easier for the air to be introduced into the case 120 more evenly.

[0044] Water heater 1 can direct a portion of the air received and guided by underside 42A of plate portion 42 to multiple inlets 125 via third space 93. Multiple inlets 125 are paths for introducing gas from gas distribution unit 10 to each burner 140, and water heater 1 can effectively guide air to each inlet 125 due to the presence of plate portion 42. Therefore, water heater 1 can easily supply primary air for combustion to each burner 140, and easily improve the combustion performance of burner 140.

[0045] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiments may be modified as follows.

[0046] In the above embodiment, the through-holes 54 are provided on both the front and rear sides and the left and right sides of the plate portion 42, but they may be provided on either one of the front, rear, left and right sides, or on multiple sides.

[0047] In the above embodiment, an air passage plate 52 was provided between the outer edge of the plate portion 42 and the bottom surface portion 121, but the air passage plate 52 may not be provided in part or all of the periphery of the plate portion 42, leaving it open.

[0048] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0049] 1: Water heater 2: Housing 3: Combustion equipment 7: Blower 10: Gas distribution section 34: Nozzle 42: Plate part 42A: Bottom surface 52: Air passage plate 54:Through hole (inlet) 91: 1st space 92:Second space 93:Third space 120: Case 121: Bottom part 124: Front wall 125: Entrance 132: Hole 140: Burner 162: Ventilation outlet

Claims

1. a combustion device including a plurality of burners for burning gas and a case for accommodating the plurality of burners, the case having a bottom surface with a plurality of holes; a blower disposed below the combustion device and supplying air; a housing that houses the combustion device and the blower; a plate portion that is disposed at a distance from the bottom surface portion and that covers the plurality of holes from below, receives the air sent from the blower with its underside, and guides the air into a space around itself; an inlet through which the air flows from a first space around the plate portion to a second space between the plate portion and the bottom surface portion; an air passage plate disposed so as to partially block the gap between the outer edge of the plate portion and the bottom surface portion; and the air that has entered the second space is introduced into the case through the plurality of holes, the air passing plate includes a front passing plate that partially closes the gap between the front end of the plate portion and the bottom surface portion, a rear passing plate that partially closes the gap between the rear end of the plate portion and the bottom surface portion, a one passing plate that partially closes the gap between one left-right end of the plate portion and the bottom surface portion, and a other passing plate that partially closes the gap between the other left-right end of the plate portion and the bottom surface portion, the front-side passing plate, the rear-side passing plate, the one-side passing plate, and the other-side passing plate are provided so as to annularly surround the second space, a plurality of through-holes are provided in each of the front-side passing plate, the rear-side passing plate, the one-side passing plate, and the other-side passing plate; The through-hole portion is the inlet Water heater.

2. The blower has an air outlet for discharging the air, The air outlet and the lower surface of the plate portion are arranged to face each other vertically. The water heater according to claim 1.

3. A gas distribution section having a plurality of nozzles for discharging the gas, the case has a front wall portion provided with a plurality of inlets, the gas distribution section is configured to cover the front wall section from the front side, the plurality of inlets are paths for introducing the gas distributed from the gas distribution unit into the case, and the gas introduced through each of the inlets is supplied to each of the burners; a third space through which the air flows is formed between the front wall portion and the gas distribution portion, a portion of the air guided by the lower surface enters the third space; The air in the third space flows into the case through the plurality of inlets. The water heater according to claim 1 or 2.

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