water heater

Abstract

To provide a technology which can easily stabilize a flow of air which tries to enter a blower, for a water heater having a combustion device and the blower.SOLUTION: A water heater 1 comprises a blower 7 for supplying air, a box body 2 for accommodating a combustion device 3 and the blower 7, and an air supply duct 140 for supplying air to the blower 7. The air supply duct 140 has a lower-end side duct 150 disposed between the blower 7 and a back face part 38 of the box body 2 at a rear side of the blower 7, and an upper-side duct 170 communicating with the lower-end side duct 150, and extending in an upward direction of the lower-end side duct 150. An air supply port 172 is disposed at an upper-end side of the upper-side duct 170. The lower-end side duct 150 and the blower 7 communicate with each other while opposing each other.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] Patent Document 1 discloses an example of a forced exhaust water heater. The water heater in Patent Document 1 is provided with a combustion fan connected to a fan motor below the combustion chamber. In this water heater, combustion air is taken into the water heater from an air supply cylinder, and the combustion fan operates to supply the taken-in combustion air into the combustion chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-114307 Summary of the Invention [Problem to be solved by the invention]

[0004] Because various components are arranged inside a water heater, the path of the air introduced from the air supply cylinder before entering the blower (combustion fan) is likely to change in various ways in a configuration such as that described in Patent Document 1. As a result, the air flow around the blower inside the water heater is difficult to stabilize, raising concerns that air may not be supplied to the blower stably.

[0005] The present disclosure relates to a water heater equipped with a combustion device and a blower, and one object of the present disclosure is to provide a technology that can easily stabilize the flow of air entering the blower. [Means for solving the problem]

[0006] The water heater according to the present disclosure includes: A blower for supplying air; a combustion device disposed above the blower, receiving a supply of air from the blower and combusting gas; a housing that houses the combustion device and the blower; an air supply duct for supplying air to the blower; Equipped with The blower has an inlet for introducing the air, The air intake duct has an air intake port located above the blower and an exhaust port connected to the inlet, and is located across the area between the blower and the rear part of the housing and the area above the blower, and guides the air from the air intake port to the exhaust port. [Effects of the Invention]

[0007] The technology disclosed herein relates to a water heater equipped with a combustion device and a blower, and is capable of stabilizing the flow of air entering the blower. [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 illustrating the configuration of the water heater of FIG. 1 with the front cover and other components omitted. [Figure 3] FIG. 3 is an exploded perspective view illustrating the configuration of the housing, packing, etc. in the water heater of FIG. [Figure 4] 4 is a perspective view partially showing the combustion device and the blower in the water heater of FIG. [Figure 5] FIG. 5 is a perspective view illustrating the configuration of an exhaust unit, a heat exchanger, a combustion device, a blower, an air intake duct, and the like in the water heater of FIG. [Figure 6] FIG. 6 is a side view illustrating the configuration of the exhaust unit, the heat exchanger, the combustion device, the blower, the air intake duct, etc. in the water heater of FIG. [Figure 7] FIG. 7 is a front view illustrating the configuration of the exhaust unit, the heat exchanger, the combustion device, the blower, the air intake duct, etc. in the water heater of FIG. [Figure 8] FIG. 8 is a cross-sectional view that schematically shows a cut surface of a part of the water heater (the rear part of the housing, the air supply duct, and the part where the blower is connected). [Figure 9] FIG. 9 is a front view of the blower and the air intake duct. [Figure 10] FIG. 10 is a front view of the air supply duct. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes exemplary embodiments of the present disclosure. Note that the following exemplary features [1] to [4] may be combined in any compatible combination.

[0010] [1] A blower for supplying air; a combustion device disposed above the blower, receiving a supply of air from the blower and combusting gas; a housing that houses the combustion device and the blower; an air supply duct for supplying air to the blower; Equipped with The blower has an inlet for introducing the air, The air supply duct has an air supply port disposed above the fan and an exhaust port communicating with the inlet, and is disposed across an area between the fan and the rear part of the housing and an area above the fan, and guides the air from the air supply port to the exhaust port. Water heater.

[0011] The water heater described in [1] is provided with an intake air duct that supplies air to the blower, and the intake air duct is arranged across the "area between the blower and the rear part of the housing" and the "area above the blower." This water heater can efficiently utilize the space between the blower and the rear part of the housing to ensure a flow path for supplying air to the blower. Furthermore, in this water heater, air is supplied to the blower through a flow path that is ensured in a fixed position and with a fixed shape in the intake air duct, making it easy to stabilize the flow of air entering the blower.

[0012] [2] A heat exchanger is provided above the combustion device, a portion of the air supply duct is disposed between the heat exchanger and the housing on the rear side of the heat exchanger, The air intake is disposed above the combustion device. The water heater described in [1].

[0013] In the water heater described in [2], the air intake port of the air intake duct is located above the combustion device. Therefore, when air near the combustion device or below the combustion device inside the housing is sent to the blower, it tends to pass near the combustion device, rise, and then be sucked in through the air intake port. In this way, air that passes near the combustion device and then enters the air intake port tends to warm up as it passes near the combustion device, making it easier for the blower to supply warm air. Therefore, this water heater can improve the combustion performance of the combustion device.

[0014] [3] The air intake duct comprises a front wall portion formed in a plate shape, and a rear wall portion formed in a plate shape and facing the front wall portion on the rear side of the front wall portion, the front wall portion and the rear wall portion being integrally connected, and the air intake duct has a flat shape in which its width in the left-right direction is larger than its width in the front-rear direction, The rear wall portion has an upper rear wall portion, at least a portion of which is disposed above the blower, and a lower rear wall portion, at least a portion of which is disposed between the blower and the rear portion and is disposed below and in front of the upper rear wall portion, and the upper rear wall portion and the lower rear wall portion form a step structure. A water heater according to [1] or [2].

[0015] The water heater described in [3] has a flattened air supply duct, which reduces the size in the front-to-rear direction and makes it easy to supply a larger amount of air. Furthermore, the "upper rear wall, at least a portion of which is located above the blower" and the "lower rear wall, which is located below and in front of the upper rear wall" form a stepped structure, which makes it easy to suppress resonance due to the presence of the stepped portion.

[0016] [4] The lower rear wall portion is provided with an auxiliary air intake port for introducing air from within the housing into the air intake duct. [3] The water heater described in [3].

[0017] When a step structure is provided, there is a problem that the step structure tends to obstruct the flow of air, but the water heater of the above [4] is provided with an auxiliary air intake port, so the introduction of air can be promoted through the auxiliary air intake port.

[0018] [5] In the air supply duct, a communication wall having the exhaust port and a separation wall arranged on the rear side of the communication wall and spaced apart from the rear surface are provided in a region between the blower and the rear surface, The separating wall is provided with an auxiliary air supply port for introducing air from inside the housing into the air supply duct. A water heater according to any one of [1] to [4].

[0019] The water heater described in [5] ensures a flow path for supplying air to the blower by efficiently utilizing the space between the blower and the rear part of the housing, but the space between the blower and the rear part of the housing is limited, making it difficult to ensure a large flow path. In this regard, the water heater has a separating wall disposed at a distance from the rear part behind the connecting wall having the exhaust port, and an auxiliary air supply port is provided in this separating wall, so that air passing through the space between the separating wall and the rear part can be introduced through the auxiliary air supply port, thereby partially promoting the introduction of air behind the connecting wall.

[0020] [6] The opening area of ​​the auxiliary air inlet and the opening area of ​​the exhaust port overlap each other in the front and rear. [5] The water heater described in [5].

[0021] In the water heater described in [6], the opening area of ​​the auxiliary air supply port and the opening area of ​​the exhaust port overlap each other from front to back, so that the air supplied from the auxiliary air supply port easily flows to the exhaust port, thereby further promoting the introduction of air behind the communication wall.

[0022] 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 60 removed from a housing 2 thereof.

[0023] In this specification, the up-down direction refers to the up-down direction of the water heater 1, and in the example of Figure 1 etc., the longitudinal direction of the water heater 1 is the up-down direction. Specifically, the vertical up-down direction when the water heater 1 is installed corresponds to the up-down direction. In the example of Figure 8, the longitudinal direction of the air supply duct 140 is the up-down direction. In the example of Figure 8, the direction of the rotation shaft 81Z of the motor 81A is the front-back direction. In other words, in the example of Figure 8, the direction of the central axis that forms the center of rotation of the motor 81A is the front-back direction. The left-right direction is a direction perpendicular to the up-down direction and the front-back direction.

[0024] 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 30 that is open at the front, and a front cover section 60 (FIGS. 1 and 3) that is detachably attached to the housing main body 30. The front cover section 60 shown in FIG. 1 closes the housing main body 30 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 disposed near the center inside the housing 2. The heat exchanger 4 is disposed above the combustion device 3 inside the housing 2. The exhaust section 5 is disposed above the heat exchanger 4 inside the housing 2. The gas distribution unit 10 is disposed between the combustion device 3 and the front cover section 60. The blower 7 is disposed below the combustion device 3 inside the housing 2.

[0025] The combustion device 3 shown in FIG. 2 combusts gas (fuel gas) supplied via a gas distribution unit 10. The combustion device 3 is disposed above the blower 7 and receives air from the blower 7. As shown in FIG. 4, the combustion device 3 includes an inner case 3A with multiple burners 12. The inner case 3A is a rectangular box-shaped case that fits within the housing 2. A burner group, consisting of flat, light- and dark-type burners 12 arranged side by side in the left-right direction, is provided within the inner case 3A. An ignition discharge electrode, a flame rod for flame detection, and the like are provided at the upper front of the inner case 3A. The inner case 3A includes a peripheral wall 3B (FIG. 5) and a partition plate 3C. The peripheral wall 3B has a front wall, a rear wall, and a pair of side walls, which are configured in a box shape. The upper end of the inner case 3A is configured as an open opening, which functions as an outlet for discharging combustion exhaust gas generated within the combustion device 3 toward the heat exchanger 4. In the combustion device 3, gas supplied from the gas distribution unit 10 flows into each burner 12. The partition plate 3C functions as the bottom of a box-shaped space (space for burning gas) that houses multiple burners 12. Multiple holes 18 are provided evenly distributed in the front, back, left, and right directions, and each hole 18 is provided as a through-hole that penetrates the plate-shaped partition plate 3C from top to bottom and functions as a vent hole through which air passes.

[0026] The heat exchanger 4 shown in FIG. 2 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 is disposed above the combustion device 3. The heat exchanger 4 includes a metal casing 4A that forms its outer shell, and a heat transfer tube housed inside the casing 4A. An opening is provided at the lower end of the casing 4A as an inlet for introducing the combustion exhaust gas, and this opening (inlet) communicates with an opening (the above-mentioned outlet) at the upper end of the inner case 3A. An opening is provided at the upper end of the casing 4A as an outlet for discharging the combustion exhaust gas. The heat exchanger 4 introduces the combustion exhaust gas discharged from the combustion device 3 into its interior, allowing it to pass through its interior, and exchanges heat between the combustion exhaust gas and water flowing inside the heat transfer tube. The combustion exhaust gas that has passed through the heat exchanger 4 is discharged into the exhaust section 5 from an opening (exhaust port) at the upper end of the casing 4A.

[0027] The exhaust section 5 shown in FIG. 2 forms a path for discharging the combustion exhaust gas. The exhaust section 5 is disposed above the heat exchanger 4. The exhaust section 5 comprises an exhaust section main body 5A that constitutes the outer wall (outer shell) of the exhaust section 5, and an exhaust pipe 100. An opening is provided at the lower end of the exhaust section main body 5A as an inlet for introducing the combustion exhaust gas. This opening (inlet) communicates with an opening (exhaust port) at the upper end of the casing 4A. The exhaust section 5 functions to introduce the combustion exhaust gas discharged from the heat exchanger 4 into itself, guide it upward, and discharge it to the outside of the water heater 1 via the exhaust pipe 100.

[0028] In the water heater 1, the combustion device 3 combusts gas (fuel gas) supplied into the combustion device 3 via the gas distribution unit 10 within the inner case 3A. The exhaust gas (combustion exhaust gas) generated by the combustion of the gas within the inner case 3A is discharged from an opening at the top end of the inner case 3A and flows into the casing 4A of the heat exchanger 4. The combustion exhaust gas that has flowed into the heat exchanger 4 passes through the heat exchanger 4 and flows into the exhaust unit main body 5A of the exhaust unit 5. The exhaust gas that has flowed into the exhaust unit 5 then passes through the exhaust pipe 100 and is discharged to the outside of the water heater 1.

[0029] As shown in FIG. 2, the housing 2 houses various components such as the combustion device 3 and the heat exchanger 4. As shown in FIG. 3, the housing 2 includes a housing main body 30, a front cover main body 60A, and a packing 90. As shown in FIGS. 1 and 3, the front cover main body 60A constitutes the front portion of the housing 2. The housing main body 30 is a box-shaped case body that houses the combustion device 3, the heat exchanger 4, and the like. In the example of FIG. 1, the front cover main body 60A is fitted with an operating device 130 to form a plate-shaped front cover portion 60. The front cover portion 60 is a lid-like body that can be attached to and detached from the front side of the housing main body 30.

[0030] As shown in FIG. 3, the front cover main body 60A has a front wall portion 62, an upper wall portion 66, a lower wall portion 64, and side wall portions 68 and 69, and is shaped like a shallow box with an open rear side. An opening 62Z is ​​formed in the front wall portion 62, and the operating device 130 is fitted into the opening 62Z as shown in FIG. 1. As shown in FIG. 3, the housing main body 30 has an upper wall portion 32, a lower wall portion 34, a pair of side wall portions 35 and 36, and a rear wall portion (rear portion) 38, which are connected together. The upper wall portion 32, the lower wall portion 34, the pair of side wall portions 35 and 36, and the rear wall portion 38 are all formed in a plate shape. The upper wall portion 32, the lower wall portion 34, and the pair of side wall portions 35 and 36 are connected together and arranged to surround, above, below, left, and right, the area (the housing interior space) in which the combustion device 3 and the heat exchanger 4 are housed. The housing body 30 is box-shaped with an opening 40 on the front side. The opening 40 is defined by the front end of the upper wall portion 32, the front end of the lower wall portion 34, and the front ends of the pair of side walls 35, 36, and is configured to be open to the front.

[0031] 3, the packing 90 is a member that seals the gap between the housing main body 30 and the front cover main body 60A. The packing 90 is arranged along the opening 40 of the housing main body 30, along the annular rear end of the front cover main body 60A, and is sandwiched between the front cover main body 60A and the housing main body 30 from the front and rear.

[0032] 3, in the front cover 60, fixing portions 71A and 71B forming part of the front wall 62 overlap front-to-rear with fixed portions 43A and 43B provided on the housing main body 30, respectively, and one screw member 21 is inserted into screw hole 53X of fixed portion 43A and screw hole 71X of fixing portion 71A for fixing, and the other screw member 21 is inserted into screw hole 53Y of fixed portion 43B and screw hole 71Y of fixing portion 71B for fixing. Furthermore, protruding portions 72C and 72D provided on the lower wall 64 overlap the lower wall 34, and one screw member 22 is inserted into screw hole 54X of fixed portion 44A and screw hole 72X of fixing portion 72A for fixing, and the other screw member 22 is inserted into screw hole 54Y of fixed portion 44B and screw hole 72Y of fixing portion 72B for fixing. 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. The water introduced into water inlet 192 is supplied to the 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 discharged from 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.

[0033] In the water heater 1 shown in FIG. 2, the gas inlet 191 is an inlet through which gas is introduced from a gas pipe provided outside the water heater 1. The gas introduced into the gas inlet 191 is supplied to the gas distribution unit 10 via a gas supply section (details not shown) equipped with a main valve, a proportional valve, etc. The gas (fuel gas) supplied to the gas distribution unit 10 is distributed to pass through a plurality of holes (not shown) provided in the combustion device 3, and is supplied to the combustion device 3 via these holes. The combustion device 3 combusts the gas (fuel gas) supplied into the combustion device 3 via the gas distribution unit 10. The exhaust gas (combustion exhaust gas) generated by the combustion of the gas in the combustion device 3 flows from the combustion device 3 into the heat exchanger 4, passes through the heat exchanger 4, and is discharged to the outside (outside the water heater 1) from the exhaust section 5.

[0034] 2. Blower The blower 7 shown in Fig. 4 etc. is a device that supplies air (air for combustion). As shown in Figs. 5 and 6, the blower 7 is disposed below the combustion device 3. Specifically, the blower 7 is disposed below the partition plate 3C described above. Specifically, as shown in Fig. 2, the exhaust section 5, the heat exchanger 4, and the combustion device 3 are disposed in this order, stacked vertically, and the blower 7 is disposed below the combustion device 3, stacked vertically.

[0035] As shown in FIG. 6, blower 7 mainly includes a case 80 and a drive unit 81. Drive unit 81 includes a motor 81A and a plurality of blades 81B. In FIG. 8, the area of ​​motor 81A is simply indicated by a hatched area. Motor 81A has a rotatable shaft 81Z, which is fixed to an annular blade group including a plurality of blades 81B. Motor 81A is controlled by a control device (not shown) and can be driven to rotate shaft 81Z.

[0036] The case 80 has a front surface portion 83 forming a front wall, a back surface portion 82 forming a rear wall, and an annular wall 84. The front surface portion 83 and the back surface portion 82 are arranged facing each other from the front to the rear. The annular wall 84 is arranged between the front surface portion 83 and the back surface portion 82 so as to surround the multiple blades 81B from above, below, left, and right. The multiple blades 81B forming part of the drive unit 81 are arranged inside the case 80 and can rotate within the case 80.

[0037] The back surface portion 82 is formed in a plate shape with its thickness direction extending in the front-to-rear direction. The back surface portion 82 is disposed facing the front wall portion 141 of the air intake duct 140 in the front-to-rear direction. An inlet 88 is provided in the back surface portion 82. The inlet 88 is a hole that penetrates the back surface portion 82 in the thickness direction and is a hole through which air passes. The inlet 88 forms a path for introducing air from outside the case 80 into the case 80, and more specifically, forms a path for guiding the air in the air intake duct 140 to the front side and introducing it into the case 80.

[0038] The front surface portion 83 is formed in a plate shape with its thickness direction in the front-to-rear direction. The front surface portion 83 is disposed adjacent to the motor 81A, and the motor 81A is fixed to the front surface portion 83. A part of the motor 81A (such as a part of the rotating shaft 81Z) is disposed inside the case 80 through a hole provided in the front surface portion 83. The annular wall 84 is formed integrally with the front surface portion 83 and the back surface portion 82. The space surrounded by the front surface portion 83, the back surface portion 82, and the annular wall 84 is the space in which the multiple blades 81B rotate, and is the space in which air flows inside the case 80.

[0039] As shown in Fig. 4, an exhaust port 89 is provided on the upper end side of the case 80. In the example of Fig. 4, the exhaust port 89 is an opening provided on the upper end of the case 80. The exhaust port 89 forms a path for discharging air inside the case 80 upward, and is open upward. The case 80 is fixed so that the exhaust port 89 is positioned near the lower end of the combustion device 3.

[0040] In blower 7 configured as described above, motor 81A is driven to rotate multiple blades 81B within case 80, and the rotation of multiple blades 81B creates an air flow within case 80, causing air in air supply duct 140 to be drawn into case 80 through inlet 88. Within case 80, an air flow occurs such that air introduced from inlet 88 is discharged from outlet 89, and this flow causes air to be released upward from outlet 89. The air discharged upward from outlet 89 flows toward combustion device 3. There does not need to be a member between outlet 89 and partition plate 3C, and some member may be interposed, and the member may function to disperse the air.

[0041] 3.Air supply duct Air intake duct 140 shown in Figures 5 to 7 etc. is a duct for supplying air to blower 7. Air intake duct 140 constitutes a flow path for air up to blower 7. Air intake duct 140 is a component that guides air introduced from air intake port 172 shown in Figures 5 and 8 to exhaust port 174 shown in Figure 8, and is a component that sends air into case 80 via exhaust port 174.

[0042] As shown in FIG. 8 , air supply duct 140 includes a plate-shaped front wall 141 and a plate-shaped rear wall 142 that is also provided behind front wall 141 and faces front wall 141. Air supply duct 140 has front wall 141 and rear wall 142 that are integrally connected, forming a flat shape in which its left-right width W2 ( FIG. 7 ) is greater than its front-to-rear width W1. In the example shown in FIGS. 9 and 10 , the direction perpendicular to the widest flat surface of outer surface 141A (front surface) of front wall 141 of air supply duct 140 is the front-to-rear direction, and this front-to-rear direction is the thickness direction of air supply duct 140. The longitudinal direction of air supply duct 140 (specifically, the long side direction of the front-view shape of air supply duct 140, which is rectangular when viewed from the front) is the up-down direction. The direction perpendicular to the thickness direction and the up-down direction is the left-to-right direction. The width W1 is the thickness (maximum thickness) of the portion where the thickness is greatest in air supply duct 140. The width W2 is the left-right width (maximum width in the left-right direction) of the portion where the width in the left-right direction is greatest in air supply duct 140.

[0043] Air supply duct 140 includes lower-end duct 150 and upper duct 170. Lower-end duct 150 is a portion of air supply duct 140 that is located rearward of fan 7 and between fan 7 and rear wall portion (rear portion) 38 of housing 2. Specifically, lower-end duct 150 is a region AR1 (FIGS. 8 and 9) below the height of the upper end of the portion of air supply duct 140 that is located between fan 7 and rear wall portion (rear portion) 38 (the height of position H in the vertical direction in FIGS. 8 and 9). Upper duct 170 is a region AR2 of air supply duct 140 that is above region AR1. In other words, the entire portion of air supply duct 140 above position H is not located between fan 7 and rear wall portion (rear portion) 38, and at least a portion of the portion below position H is located between fan 7 and rear wall portion (rear portion) 38. In the example of FIGS. 8 and 9, the lower end duct 150 is disposed between the blower 7 and the rear side wall portion (rear portion) 38 over the entire area AR1 below the position H in the air supply duct 140 in the vertical direction.

[0044] 8 to 10, the upper duct 170 is configured to communicate with the lower-end duct 150 and extend above the lower-end duct 150. The upper duct 170 has a shape that is long in the vertical direction. A part of the upper duct 170 is disposed between the heat exchanger 4 and the housing 2 on the rear side of the heat exchanger 4. Another part of the upper duct 170 is disposed between the combustion device 3 and the housing 2 on the rear side of the combustion device 3. In other words, the upper duct 170 is disposed across the area where the combustion device 3 is disposed and the area where the heat exchanger 4 is disposed in the vertical direction.

[0045] As shown in FIG. 8 , an air intake port 172 is provided at the upper end of the upper duct 170. In the example of FIG. 8 , the opening provided at the upper end of the upper duct 170 is the air intake port 172. The air intake port 172 is provided above the lower end of the combustion device 3, and more specifically, is arranged above the upper end of the combustion device 3. The air intake port 172 is provided above the lower end of the heat exchanger 4 and is provided close to the boundary between the heat exchanger 4 and the exhaust section 5. The air intake port 172 opens upward. Therefore, air entering the air intake duct 140 through the air intake port 172 flows from the upper side to the lower side of the air intake port 172.

[0046] In the water heater 1, the lower-end duct 150 and the blower 7 communicate with each other while facing each other. In the example of FIG. 8 , a front surface 151 of the lower-end duct 150 is connected to a rear surface 82 of the case 80. The front surface 151 is a portion of the front wall 141 that is disposed in an area AR1 of the lower-end duct 150. The front surface 151 is provided with a bulging portion 151A, which is a wall portion that bulges forward. A cylindrical protrusion 151B is provided at the front end of the bulging portion 151A. The bulging portion 151A is a portion that bulges forward more than the area of ​​the front wall 141 other than the bulging portion 151A. As shown in FIG. 10 , most of the area of ​​the front wall 141 other than the bulging portion 151A is a flat portion having a plate surface perpendicular to the front-to-rear direction, and the bulging portion 151A bulges out so as to bulge forward more than this flat portion. Bulging portion 151A corresponds to an example of a communication wall, has exhaust port 174, and functions as a wall portion disposed in the region between blower 7 and rear wall portion (rear portion) 38 in air supply duct 140. In the example of FIG. 8 , cylindrical protrusion 151B is inserted into inlet 88, which is a circular hole, so that protrusion 151B and inlet 88 are fitted together and connected, thereby connecting the space inside lower-end duct 150 to the space inside case 80. As shown in FIG. 8 , upper end 151Z of bulging portion 151A is disposed above and forward of connecting portion 182, which will be described later, and upper end 151Z and connecting portion 182 form a flow path that directs air downward and forward. More specifically, a portion of bulging portion 151A above connecting portion 182 and connecting portion 182 form a flow path that directs air flowing inside air supply duct 140 downward and forward.

[0047] As shown in FIG. 8 , in air supply duct 140, rear wall 142 has upper rear wall 178 and lower rear wall 180. Upper rear wall 178 is a wall that is at least partially located above blower 7. Lower rear wall 180 is a wall that is at least partially located between blower 7 and rear side wall (rear portion) 38, and is located below and in front of upper rear wall 178. In rear wall 142, upper rear wall 178 and lower rear wall 180 form a stepped structure. Lower rear wall 180 includes separating wall 181 and connecting portion 182. Upper rear wall 178 is a wall that is configured in a plate shape. Most of the area of ​​the front surface (inner surface) of upper rear wall 178 is a first flat surface that is perpendicular to the front-to-rear direction. The separating wall 181 is a wall portion configured in a plate shape. Most of the area of ​​the front surface (inner surface) of the separating wall 181 is a flat surface perpendicular to the front-rear direction, and is configured as a second flat surface that is located further forward than the first flat surface and parallel to the first flat surface. The separating wall 181 is disposed rearward of the bulging portion 151A (communicating wall) and spaced apart from the rear side wall portion (rear portion) 38. The connecting portion 182 is a plate-like portion configured integrally with the upper rear wall portion 178 and the separating wall 181, and is a portion that is connected to the lower end of the upper rear wall portion 178 and to the upper end of the separating wall 181. The connecting portion 182 is disposed at an incline with respect to the front-rear direction. The inner surface (front surface) of the connecting portion 182 is an inclined surface that becomes more forward as it becomes lower.

[0048] In the configuration of FIG. 8, the portion of rear wall 142 that is arranged in the region of lower-end duct 150 is rear surface 152. In the example of FIG. 8, rear surface 152 is formed by a part of upper rear wall 178 and lower rear wall 180. Separation wall 181 is provided spaced forward from rear sidewall 38 (rear portion). A space through which air can flow is formed between separation wall 181 and rear sidewall 38. At least a part of separation wall 181 (the entirety in the example of FIG. 7 etc.) is arranged between blower 7 and rear sidewall 38 on the rear side of blower 7.

[0049] 7 and 8, an opening 189 for introducing air from within the housing 2 into the air supply duct 140 is provided in the lower rear wall 180. The opening 189 corresponds to an example of an auxiliary air supply port and functions as a hole for introducing air from within the housing 2 into the air supply duct 140. Specifically, the opening 189 is formed in the partition wall 181. The size of the opening area of ​​the opening 189 is smaller than the opening area of ​​the air supply port 172. As shown in FIG. 10, the opening area of ​​the opening 189 (auxiliary air supply port) and the opening area of ​​the exhaust port 174 overlap in the front-rear direction. In the example of FIG. 10, when the opening 189 and the exhaust port 174 are projected onto an imaginary plane perpendicular to the front-rear direction, the projection figure (specifically, a rectangular projection figure) of the inner edge of the opening 189 projected onto the imaginary plane is located inside the projection figure (specifically, a circular projection figure) of the inner edge of the exhaust port 174 projected onto the imaginary plane.

[0050] 4.Example of effects The water heater 1 is provided with an air intake duct 140 that supplies air to the blower 7, and the air intake duct 140 is arranged across the "area between the blower 7 and the rear sidewall (rear portion) 38 of the housing 2" and the "area above the blower 7." The water heater 1 can ensure a flow path for supplying air to the blower 7 by efficiently utilizing the space between the blower 7 and the rear sidewall (rear portion) 38. Furthermore, in the water heater 1, air is supplied to the blower 7 through a flow path that is ensured at a fixed position and with a fixed shape in the air intake duct 140, which makes it easy to stabilize the flow of air attempting to enter the blower 7.

[0051] In the water heater 1, the heat exchanger 4 is provided above the combustion device 3, a portion of the air intake duct 140 is disposed between the heat exchanger 4 and the housing 2 behind the heat exchanger 4, and the air intake port 172 is disposed above the combustion device 3. In this manner, in the water heater 1, the air intake port 172 of the air intake duct 140 is disposed above the combustion device 3. Therefore, when air near the combustion device 3 or below the combustion device 3 in the housing 2 is sent to the blower 7, it tends to pass near the combustion device 3, rise, and then be sucked in through the air intake port 172. In this manner, the air that passes near the combustion device and then enters the air intake port 172 tends to warm up as it passes near the combustion device 3, and therefore the blower 7 tends to supply warmed air. Therefore, this water heater 1 can improve the combustion performance of the combustion device 3.

[0052] In water heater 1, air supply duct 140 includes front wall 141 configured in a plate shape and rear wall 142 configured in a plate shape and provided rearward of front wall 141 facing front wall 141, front wall 141 and rear wall 142 being integrally connected to form a flat shape whose width in the left-right direction is greater than its width in the front-to-rear direction. Rear wall 142 includes upper rear wall 178, at least a portion of which is located above blower 7, and lower rear wall 180, at least a portion of which is located between blower 7 and rear wall 38 (rear portion) and is located below and in front of upper rear wall 178, and upper rear wall 178 and lower rear wall 180 form a step structure. In this way, since the water heater 1 has the above-mentioned flattened shape of the air supply duct 140, it is easy to supply a larger amount of air with a configuration that keeps the size in the front-to-rear direction small. Furthermore, since the "upper rear wall portion 178, at least a portion of which is arranged above the blower 7" and the "lower rear wall portion 180, which is arranged below and in front of the upper rear wall portion 178" form a stepped structure, the presence of the stepped portion makes it easy to suppress resonance.

[0053] The lower rear wall 180 is provided with an opening 189 (auxiliary air supply port) for introducing air from inside the housing 2 into the air supply duct 140. When a stepped structure is provided, there is a problem that the step structure is likely to obstruct the flow of air, but since the water heater 1 is provided with the opening 189 (auxiliary air supply port), the introduction of air can be promoted through the opening 189 (auxiliary air supply port).

[0054] In air supply duct 140, a region between blower 7 and rear sidewall portion (rear portion) 38 is provided with bulging portion (communicating wall) 151A having exhaust port 174, and separating wall 181 arranged rearward of bulging portion (communicating wall) 151A and spaced apart from rear sidewall portion (rear portion) 38, and separating wall 181 is provided with opening 189 (auxiliary air supply port) for introducing air from inside housing 2 into air supply duct 140. This water heater 1 efficiently utilizes the space between blower 7 and opening 189 (auxiliary air supply port) to ensure a flow path for supplying air to blower 7, but because the space between blower 7 and opening 189 (auxiliary air supply port) is limited, it is not possible to ensure a very large flow path. In this regard, the water heater 1 is provided with a separation wall 181 arranged at a distance from the rear side wall portion (rear portion) 38 on the rear side of the bulge portion (communicating wall) 151A having the exhaust port 174, and this separation wall 181 is provided with an opening 189 (auxiliary air supply port), so that air passing through the space between the separation wall 181 and the opening 189 (auxiliary air supply port) can be introduced through the opening 189 (auxiliary air supply port), thereby partially promoting the introduction of air on the rear side of the bulge portion (communicating wall) 151A.

[0055] In water heater 1, the opening area of ​​opening 189 (auxiliary air supply port) and the opening area of ​​exhaust port 174 overlap each other in the front-to-rear direction, so that air supplied from opening 189 (auxiliary air supply port) easily flows to exhaust port 174. This further promotes the introduction of air on the rear side of bulging portion (communication wall) 151A.

[0056] In water heater 1, the opening area of ​​opening 189 is smaller than the opening area of ​​air supply port 172, so the introduction of air through opening 189 is relatively suppressed. Therefore, in water heater 1, the benefits of sending air into the air supply duct through air supply port 172 (the benefits of stabilizing the air flow and increasing the air temperature) are unlikely to be lost.

[0057] <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.

[0058] In the above embodiment, only one opening 189 is provided in the separating wall 181, but a plurality of openings may be provided.

[0059] In the above embodiment, the air intake port 172 was located near the boundary between the heat exchanger 4 and the exhaust section 5, but it may be located above this position (for example, above the lower end of the exhaust section 5) or below this position (for example, below the lower end of the heat exchanger 4).

[0060] 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]

[0061] 1: Water heater 2: Housing 3: Combustion equipment 4: Heat exchanger 7: Blower 80: Case 82: Back part 88: Entrance 89: Outlet 140: Air supply duct 141: Front wall 142: Rear wall 150: Lower duct 151: Front part 151A: Swelling part (communicating wall) 170: Upper duct 172: Air supply port 174: Exhaust port 180: Constriction section 181: Separation wall 189: Opening (auxiliary air supply port)

Claims

1. A blower for supplying air; a combustion device disposed above the blower, receiving a supply of air from the blower and combusting gas; a housing that houses the combustion device and the blower; an air supply duct for supplying air to the blower; Equipped with The blower has an inlet for introducing the air, the air intake duct has an air intake port disposed above the fan and an exhaust port communicating with the inlet, and is disposed across an area between the fan and a rear portion of the housing and an area above the fan, and is configured to guide the air from the air intake port to the exhaust port; the air supply duct includes a plate-shaped front wall portion and a plate-shaped rear wall portion that is also disposed rearward of the front wall portion and faces the front wall portion, the front wall portion and the rear wall portion being integrally connected to each other, and the air supply duct has a flat shape whose width in the left-right direction is greater than its width in the front-rear direction, the rear wall portion has an upper rear wall portion, at least a portion of which is disposed above the blower, and a lower rear wall portion, at least a portion of which is disposed between the blower and the rear portion and is disposed below and forward of the upper rear wall portion, and the upper rear wall portion and the lower rear wall portion form a stepped structure; a communication wall having the exhaust port and a separation wall arranged rearward of the communication wall and spaced apart from the rear surface portion are provided in the air supply duct in a region between the blower and the rear surface portion, the lower rear wall portion includes the spacing wall; the separating wall is provided with an auxiliary air supply port for introducing air from within the housing into the air supply duct; The opening area of ​​the auxiliary air supply port and the opening area of ​​the exhaust port overlap each other in the front and rear direction. Water heater.

2. a heat exchanger is provided above the combustion device; a portion of the air supply duct is disposed between the heat exchanger and the housing on the rear side of the heat exchanger, The air intake is disposed above the combustion device. The water heater according to claim 1.

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