water heater

Abstract

To provide a water heater facilitating winding a resin sheet around a casing of a combustion chamber, and preventing the resin sheet from being carelessly damaged.SOLUTION: A water heater 1 is such that: an upstream end of a hot-water supply pipe 42 connected to a hot water outlet 10 in the downstream end is connected to a downstream end of an upper stage of a hot-water supply side heat transfer pipe 30 disposed in a middle casing 18 of a combustion chamber 16; a linear part 43 linearly extending in a vertical direction in the left front of a lower casing 17 and the middle casing 18 is provided in the hot-water supply pipe 42; and due to that a resin sheet 50 is positioned in the outside of the hot-water supply pipe 42 and is wound so as to be folded from the lateral face side to the front face side of the lower casing 17 and the middle casing 18 along the surface of the linear part 43, the resin sheet 50 can be easily wound around the lower casing 17 and the middle casing 18 constituting the combustion chamber 16 so as to make the water heater easily producible.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a water heater equipped with an overheat prevention device formed by wrapping a resin sheet on which a conductive pattern is formed around a casing of a combustion chamber equipped with a burner. [Background technology]

[0002] In conventional water heaters, as described in Patent Document 1, for example, a resin sheet is wrapped around the casing of a combustion chamber to detect cracks or other damage caused by abnormal overheating of the casing. The resin sheet is also provided with clips that hold the pipes together, and the clips are attached to pipes (e.g., water supply pipes) arranged on the surface of the casing to prevent the resin sheet from coming into direct contact with the casing. A predetermined conductive pattern is printed on the resin sheet, and the conductive pattern is electrically connected to a controller that controls the combustion of the burner. By detecting breakage of the conductive pattern due to melting or the like of the resin sheet, abnormal overheating of the casing is detected, and the supply of fuel gas to the burner is subsequently stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4190057 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional water heaters have had problems with workability, such as difficulty in wrapping the resin sheet around the combustion chamber casing, and there has also been a problem that the clips tend to accidentally damage the resin sheet, particularly during manufacturing.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a water heater in which a resin sheet can be easily wrapped around the combustion chamber casing and in which the resin sheet is less likely to be accidentally damaged. [Means for solving the problem]

[0006] In order to achieve the above objectives, Akira is The hot water heater is equipped with an overheat prevention device formed by wrapping a resin sheet with a conductive pattern around a casing of a combustion chamber equipped with a burner, and the upstream end of a hot water outlet pipe, the downstream end of which is connected to a hot water outlet, is connected to the casing, and the hot water outlet pipe has a straight section that extends linearly in the vertical direction at the front left or front right of the casing, and the resin sheet is located outside the hot water outlet pipe and is wrapped around the surface of the straight section from the side to the front of the casing. On the other hand, The upstream side of the straight section in the hot water pipe crosses the front of the casing from left to right above the straight section, and at this crossing part, the side connected to the casing and the straight section side are connected by a clip, and the resin sheet is wrapped around the casing below the clip. [Effects of the Invention]

[0007] According to the present invention, the upstream end of the hot water outlet pipe, whose downstream end is connected to the hot water outlet, is connected to the casing, and the hot water outlet pipe is provided with a straight section that extends linearly in the vertical direction at the front left or front right of the casing.The resin sheet is located on the outside of the hot water outlet pipe and is wrapped along the surface of the straight section from the side to the front of the casing, so that the resin sheet can be easily wrapped around the combustion chamber casing, resulting in a water heater that is easy to manufacture. Furthermore, the upstream side of the straight section of the hot water outlet pipe crosses the front face of the casing from left to right above the straight section, and at this crossing point, the side connected to the casing and the straight section side are connected by a clip, and the resin sheet is wrapped around the casing below the clip, so the clip and the resin sheet do not interfere with each other. Therefore, the resin sheet is less likely to be accidentally damaged, especially during manufacturing. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an explanatory diagram showing the water heater from the front side. [Figure 2] FIG. 2 is an explanatory diagram showing the water heater from the front side with the front cover removed. [Figure 3] FIG. 2 is an explanatory diagram showing a cross section taken along line AA in FIG. [Figure 4] This is an oblique view of the inside of the housing as seen from the left rear, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. [Figure 5] This is an oblique view of the inside of the housing as seen from the right rear, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. [Figure 6] This is an oblique view of the inside of the housing as seen from the front right, with the front cover, the left and right side panels of the box body, the back panel, and the resin sheet omitted. [Figure 7] FIG. 10 is a perspective view of the inside of the housing from the left rear, with the neutralizer omitted. [Figure 8] This is a perspective view of the inside of the housing from the front right, with the neutralizer omitted. [Figure 9] FIG. 10 is an explanatory diagram showing how the resin sheet is fastened to the back plate with screws. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A water heater according to an embodiment of the present invention will be described in detail below with reference to the drawings. (Explanation of the overall structure of the water heater) FIG. 1 is an explanatory diagram showing the water heater 1 from the front side. FIG. 2 is an explanatory diagram showing the water heater 1 from the front side with the front cover 4 removed. FIG. 3 is an explanatory diagram showing a cross section taken along line AA in FIG. 1. FIG. 4 is a perspective view of the interior of the housing 2 from the rear left, omitting the front cover 4, the left and right side panels 7A and 7B of the box body 3, the back panel 8, and the resin sheet 50. FIG. 5 is a perspective view of the interior of the housing 2 from the rear right, omitting the front cover 4, the left and right side panels 7A and 7B of the box body 3, the back panel 8, and the resin sheet 50. FIG. 6 is a perspective view of the interior of the housing 2 from the front right, omitting the front cover 4, the left and right side panels 7A and 7B of the box body 3, the back panel 8, and the resin sheet 50. FIG. 7 is a perspective view of the interior of the housing 2 from the rear left, omitting the neutralizer 55. FIG. 8 is a perspective view of the interior of the housing 2 from the front right, omitting the neutralizer 55. FIG. 9 is an explanatory diagram showing how the resin sheet 50 is fastened to the back panel 8 with screws.

[0010] The water heater 1 has a vertically long box-shaped housing 2. The housing 2 comprises a box body 3 and a front cover 4. The box body 3 is open at the front and has a deep bottom at the front and rear. The front cover 4 is screwed to the box body 3 from the front to close the front. A cylindrical exhaust port 37, which is provided on the front side of the upper casing 19 described below, penetrates the top of the front cover 4.

[0011] The box body 3 comprises a top plate 5, a bottom plate 6, left and right side plates 7A and 7B, and a back plate 8. The bottom plate 6 is provided with a water inlet 9 for connection to an external water pipe, a hot water outlet 10 for connection to an external hot water tap, a bath return port 11 for connection to an external bathtub, and a bath supply port 12. The center of the bottom plate 6 is provided with a gas inlet 13 for connection to an external gas pipe, and a drain port 14 for connection to a neutralizer 55, which will be described later. Mounting plates 15, 15 are provided above and below the back plate 8 for installation on a wall or the like.

[0012] A combustion chamber 16 is provided at the back side of the box body 3. The combustion chamber 16 includes a lower casing 17, a middle casing 18, and an upper casing 19 that are connected in the vertical direction. The lower casing 17 houses multiple burner units 20, 20.... Each burner unit 20 is composed of multiple flat burners 21 extending in the front-rear direction, arranged side by side in the left-right direction. The number of burners 21 varies for each burner unit 20. As shown in FIG. 4, a combustion fan 22 is connected to the underside of the lower casing 17. The combustion fan 22 rotates around an axis extending in the front-rear direction by a fan motor 23 provided on the rear side. The combustion fan 22 supplies combustion air to the burner units 20. A gas distribution unit 25 is provided on the front side of the lower casing 17. The gas distribution unit 25 is equipped with multiple solenoid valves, and the burner unit 20 to be combusted can be switched by opening and closing each solenoid valve. A gas pipe 26 equipped with a main valve and a proportional valve is connected to the upstream end of the burner unit 20. The gas pipe 26 is connected to the gas inlet 13.

[0013] The inner casing 18 houses a hot water supply primary heat exchanger 27 and a bath heat exchanger 28. The hot water supply primary heat exchanger 27 has a plurality of fins 29, 29... arranged at a predetermined interval in the left-right direction, and a hot water supply side heat transfer pipe 30 that penetrates each fin 29 in a serpentine manner in two rows, upper and lower. The bath heat exchanger 28 has each fin 29 and a bath side heat transfer pipe 31 that penetrates each fin 29 in a serpentine manner between the upper and lower rows of hot water supply side heat transfer pipes 30. In other words, the water heater 1 is a one-tank, two-channel type in which the hot water supply primary heat exchanger 27 and the bath heat exchanger 28, which have different paths, are installed side by side within a single inner casing 18 and heated by a common burner unit 20.

[0014] The upper casing 19 houses a hot water secondary heat exchanger 32. The hot water secondary heat exchanger 32 houses a plurality of heat absorption pipes 33, 33... formed in a serpentine shape. As shown in FIG. 4, both ends of each heat absorption pipe 33 are connected to an inlet header 34 and an outlet header 35 provided at the front and rear of the left side surface of the upper casing 19, so that the inlet ends and outlet ends communicate with each other. The upper casing 19 and the middle casing 18 communicate with each other at their rear ends. The upper casing 19 is supported in a downwardly tilted position, and is provided with flat drain pans 36 on the front and rear sides at its front. An exhaust port 37 is connected to the front side of the drain pan 36 and faces forward.

[0015] A water supply pipe 40 is connected to the water inlet 9. The water supply pipe 40 is routed upward on the left side of the combustion chamber 16 and connected to the inlet header 34 of the upper casing 19. A relay pipe 41 is connected to the outlet header 35. As shown in Fig. 5 , the relay pipe 41 runs from the left side of the combustion chamber 16, passes behind the intermediate casing 18, and wraps around to the right side of the intermediate casing 18. The relay pipe 41 is then routed forward on the right side of the intermediate casing 18 and connected to the upstream end of the lower section of the hot water supply side heat transfer pipe 30 of the hot water supply primary heat exchanger 27.

[0016] A hot water outlet pipe 42 is connected to the downstream end of the upper section of the hot water supply side heat transfer pipe 30. As shown in Fig. 6, the hot water outlet pipe 42 wraps around from the right side of the inner casing 18 to the front of the inner casing 18, crosses the front of the inner casing 18, and moves to the left side of the inner casing 18. Then, as shown in Fig. 4, the hot water outlet pipe 42 bends downward at the front left of the inner casing 18, is routed downward in a straight line, and is then connected to the tap water outlet 10. A straight section 43 of the hot water outlet pipe 42 is connected to the water supply pipe 40 via a bypass pipe 44.

[0017] A bath return pipe 45 is connected to the bath return port 11. As shown in Figures 4 to 6, the bath return pipe 45 is routed upward along the right side of the combustion chamber 16 via a pump 46. The bath return pipe 45 then crosses the front of the inner casing 18, wraps around to the left side of the inner casing 18, and is connected to the upstream end of the bath-side heat transfer pipe 31 of the bath heat exchanger 28. The bath return pipe 45 is connected to the hot water outlet pipe 42 via a drop pipe 47. A bath supply pipe 48 is connected to the bath supply port 12. The bath supply pipe 48 is routed upward along the right side of the combustion chamber 16, and then connected to the downstream end of the bath-side heat transfer pipe 31 on the right side of the middle casing 18.

[0018] A resin sheet 50 is wrapped around the combustion chamber 16. A continuous conductive pattern 51, which meanders back and forth in the width direction and extends longitudinally, is printed on the resin sheet 50 over the entire length in the longitudinal direction. Both ends of the conductive pattern 51 are electrically connected to an electrical circuit board 66 (described later) to form an overheat prevention device. When abnormal overheating of the lower casing 17 or the middle casing 18 causes cracks or holes, resulting in the emission of combustion exhaust gas, the resin sheet 50 melts and the conductive pattern 51 breaks, causing the resistance value to suddenly increase or become infinite. The electrical circuit board 66 detects the change in resistance value and stops the supply of fuel gas to extinguish the burner unit 20.

[0019] A neutralizer 55 is disposed in front of the combustion chamber 16. The neutralizer 55 is a rectangular box when viewed from the front, and is filled with a neutralizing agent (not shown). Drain discharge pipes 56, 56 are connected to the front bottom surface of the upper casing 19 and the drain receiver 36 on the upper surface of the neutralizer 55. A drain pipe 57 is connected to the drain outlet 14 on the lower surface of the neutralizer 55.

[0020] 3, the upper part of the neutralizer 55 is fixed to bracket fittings 58 fixed downward from the middle casing 18 and the upper casing 19 via mounting fittings 59 that are L-shaped in side view. The lower part of the neutralizer 55 is fixed to a fixing bar 60 that is fixed to the lower casing 17 on the front side of the gas distribution unit 25 and extends in the left-right direction. A controller 65 is disposed below the neutralizer 55. The controller 65 includes an electrical board 66, a storage case 67, and a cover 68.

[0021] (Explanation of water heater operation) In the water heater 1, normal hot water supply is performed as follows. When the hot water tap on the external pipe connected to the hot water outlet 10 is opened to allow water to flow into the appliance and this water flow is detected by a hot water supply volume sensor installed in the water supply pipe 40, the controller 65 drives the combustion fan 22 for a predetermined time to discharge (pre-purge) the combustion exhaust gas accumulated in the combustion chamber 16. Thereafter, the controller 65 opens the main valve of the gas pipe 26 and the solenoid valve of the gas distribution unit 25, opens the proportional valve to a predetermined opening, supplies gas to the burner unit 20, and activates the igniter to ignite the burner unit 20.

[0022] As a result, the water supplied from the water supply pipe 40 exchanges heat with the combustion exhaust gas from the burner unit 20 as it flows through the heat absorption pipe 33 of the hot water secondary heat exchanger 32, recovering latent heat. The drain generated at this time is collected in the neutralizer 55 via the drain discharge pipe 56, neutralized with a neutralizing agent, and then discharged from the drain pipe 57 to the outside of the appliance. The hot water that has passed through the hot water secondary heat exchanger 32 then flows to the hot water primary heat exchanger 32 via the relay pipe 41, and as it flows through the hot water side heat transfer pipe 30, it exchanges heat with the combustion exhaust gas from the burner unit 20 to recover sensible heat. The hot water heated in this way passes through the hot water outlet pipe 42 and external piping and is discharged from the hot water tap.

[0023] The electrical board 66 of the controller 65 monitors the outlet temperature, which is the temperature of the hot water discharged immediately after the hot water primary heat exchanger 27, using an outlet temperature thermistor installed in the hot water outlet pipe 42, and drives the distribution valve installed in the bypass pipe 44 to control the flow rate (bypass rate) to the bypass pipe 44 so that the outlet temperature is maintained within a temperature range that can prevent the generation of drainage or overheating in the hot water primary heat exchanger 27. In addition, the electrical board 66 monitors the outlet hot water temperature using an outlet hot water temperature thermistor installed in the outlet hot water pipe 42, and controls the opening and closing of each solenoid valve in the gas distribution unit 25 and adjusts the opening of the proportional valve so that the outlet hot water temperature becomes the set temperature specified by the external hot water remote control or bath remote control, and also continuously changes the amount of air by controlling the operation of the combustion fan 22. When the hot water tap is closed, the electrical board 66 confirms that the signal from the hot water volume sensor has stopped, closes the main valve and the solenoid valve of the gas distribution unit 25 to extinguish the burner unit 20, and drives the combustion fan 22 for a predetermined time (post-purge).

[0024] On the other hand, when the automatic switch on the hot water remote control or bath remote control is pressed, the electrical board 66 opens the drop water solenoid valve provided in the drop pipe 47 to pass water through the hot water primary heat exchanger 27 and the hot water secondary heat exchanger 32, igniting the burner unit 20. Hot water from the hot water outlet pipe 42 is supplied to the external bathtub through the drop pipe 47 and the bath return pipe 45. When the water volume detected by the bath water volume sensor provided in the drop pipe 47 reaches the set water volume, the electrical board 66 closes the drop water solenoid valve to stop the water flow and extinguishes the burner unit 20. Next, the electrical board 66 activates the pump 46 to circulate hot water between the bath heat exchanger 28 and the bathtub. At this time, the electrical board 66 monitors the temperature of the circulating hot water using thermistors installed in the bath return pipe 45 and bath supply pipe 48, and if it detects a drop from the set temperature, it ignites the burner unit 20 and supplies combustion air using the combustion fan 22, just as when supplying hot water. Therefore, the bath circulating water circulating between the bath heat exchanger 28 and the bathtub is heated to the set temperature by heat exchange with the combustion exhaust gas from the burner unit 20 as it flows through the bath-side heat transfer pipe 31. When the set temperature is reached, the electrical board 66 stops the combustion of the burner unit 20 and stops the pump 46.

[0025] (Explanation of the winding structure of the resin sheet) The resin sheet 50 is a strip-shaped body extending in the left-right direction and is wound around the combustion chamber 16, straddling the lower casing 17 and the middle casing 18, as shown in Figures 2 and 3. Mounting holes 70, 70... are drilled in the resin sheet 50 at approximately the center in the left-right direction, above and below the conductive pattern 51, for screwing the resin sheet to the back plate 8. A clip 72 is provided in the outlet pipe 42 at a portion that crosses the front of the middle casing 18 for connecting the pipes together. The outlet pipe 42 also has a linear portion 43 extending downward in a straight line at the left front of the middle casing 18, as described above. Screw fastening portions 71, 71... are provided on the inner surface of the back plate 8 for screwing the resin sheet 50.

[0026] To install the resin sheet 50 in the housing 2, first, the resin sheet 50 is screwed to the back panel 8 as shown in FIG. 9 . Next, the combustion chamber 16 is installed in front of the screwed locations on the resin sheet 50. Furthermore, on the outside of the pipes protruding outward from the middle casing 18, the left and right sides of the resin sheet 50 are folded forward so that the right portion of the resin sheet 50 is aligned with the right side surfaces of the lower casing 17 and the middle casing 18, and the left portion of the resin sheet 50 is aligned with the left side surfaces of the lower casing 17 and the middle casing 18, respectively. Then, of the left and right sides of the resin sheet 50, the portions that protrude forward beyond the lower casing 17 and the middle casing 18 are folded toward the front surfaces of the lower casing 17 and the middle casing 18. At this time, the resin sheet 50 is folded, particularly at the left portion of the resin sheet 50, along the surface of the linear portion 43. Finally, the left and right ends of the resin sheet 50 are integrated in front of the lower casing 17 and the middle casing 18 by, for example, adhering them together. As a result, the resin sheet 50 is installed inside the housing 2 in a state where it is wrapped around the combustion chamber 16. Note that, when the resin sheet 50 is installed, as described above, the pipes are located between the resin sheet 50 and the lower casing 17 and the intermediate casing 18, and the resin sheet 50 is not in contact with the combustion chamber 16. In addition, the portion of the outlet pipe 42 that crosses the front of the intermediate casing 18 is located above the straight portion 43 and the resin sheet 50, and the clip 72 that connects the pipes in front of the intermediate casing 18 is also located above the resin sheet 50.

[0027] (Effects of the invention relating to the winding structure of the resin sheet) According to the water heater 1 having the above-described configuration, the upstream end of the hot water outlet pipe 42, whose downstream end is connected to the hot water outlet 10, is connected to the downstream end of the upper section of the hot water supply side heat transfer pipe 30 provided in the middle casing 18 of the combustion chamber 16, and the hot water outlet pipe 42 is provided with a straight section 43 that extends linearly in the vertical direction at the front left of the lower casing 17 and the middle casing 18, and the resin sheet 50 is located outside the hot water outlet pipe 42 and is wrapped around the surface of the straight section 43 by being folded from the side of the lower casing 17 and the middle casing 18 to the front, so that the resin sheet 50 can be easily wrapped around the lower casing 17 and the middle casing 18 that make up the combustion chamber 16, making the water heater 1 easy to manufacture.

[0028] Furthermore, the upstream side of the straight section 43 in the hot water outlet pipe 42 crosses the front surface of the inner casing 18 from side to side above the straight section 43, and at this crossing portion, the side connected to the inner casing 18 and the straight section 43 side are connected by clips 72, and the resin sheet 50 is wrapped around the lower casing 17 and the inner casing 18 below the clips 72, so that the clips 72 and the resin sheet 50 do not interfere with each other. Therefore, the resin sheet 50 is less likely to be accidentally damaged, particularly during manufacturing, in the water heater 1.

[0029] The water heater of the present invention is not limited to the above-described embodiment, and the overall configuration of the water heater (for example, the position of the hot water outlet and the routing of each pipe, etc.), as well as the configuration related to the winding structure of the resin sheet, can be appropriately modified as needed.

[0030] For example, in the above embodiment, a straight section of the outlet pipe is provided at the front left of the combustion chamber, but it may also be provided at the front right, and the design of how the outlet pipe is routed can be modified as appropriate. In addition, in the above embodiment, the combustion chamber comprises a lower casing, a middle casing, and an upper casing, and the resin sheet is wound so as to straddle the lower casing and the middle casing, but the specific structure of the combustion chamber and the winding position of the resin sheet can also be designed and modified as appropriate. Furthermore, the resin sheet may be screwed to the side panel of the housing, or both ends of the resin sheet may be integrated on the side of the combustion chamber, and the design can also be changed to determine how the resin sheet is specifically wrapped around the combustion chamber. [Explanation of symbols]

[0031] 1··Water heater, 2··Hot water supply unit, 3··Box body, 10··Hot water outlet, 16··Combustion chamber, 17··Lower casing, 18··Middle casing, 19··Upper casing, 20··Burner unit, 42··Hot water outlet pipe, 43··Straight section, 50··Resin sheet, 51··Conductive pattern, 72··Clip.

Claims

[Claim 1] A water heater equipped with an overheating prevention device formed by wrapping a resin sheet on which a conductive pattern is formed around a casing of a combustion chamber equipped with a burner, The upstream end of a tap pipe, the downstream end of which is connected to the tap outlet, is connected to the casing; The outlet pipe is provided with a straight portion extending linearly in the vertical direction at the left front or right front of the casing, The resin sheet is located outside the outlet pipe and is wrapped around the casing from the side to the front along the surface of the straight portion. The upstream side of the outlet pipe from the straight section crosses the front surface of the casing from left to right above the straight section, and at the crossing portion, the side connected to the casing and the straight section side are connected by a clip; The water heater is characterized in that the resin sheet is wrapped around the casing below the clip.

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