water heater

Abstract

This invention provides a water heater that integrates a microbubble generator within its casing, a configuration that helps to suppress increases in manufacturing costs. The water heater 1 includes: a casing 8, combustion devices 31 and 32, heat exchangers 41A to 42B, a water supply pipe P1, a hot water pipe P2, a water supply connection component 10, a hot water supply connection component 20, and a water flow control unit 50. The water heater 1 also includes a microbubble generator 9, which is connected within the casing 8 to one of the water supply pipes P1 and P2 (i.e., a specific pipe P2), and is formed as a generally cylindrical shape with a length greater than its outer width in the axial X9 direction, generating microbubbles from the hot water flowing inside. The microbubble generator 9 has: an inlet 91H located on one side in the axial X9 direction where hot water flows in from the upstream side P2U of the specific pipe P2, and an outlet 92H located on the other side in the axial X9 direction where hot water containing microbubbles flows out to the downstream side P2D of the specific pipe P2. The microbubble generator 9 is located below the flame ports 31F and 32F of the burners 31B and 32B.

Description

Technical Field

[0001] This invention relates to a water heater. Background Technology

[0002] Patent document 1 discloses an example of a conventional water heater. This water heater includes: a shell, a combustion device, and a heat exchanger.

[0003] The housing has a main body. The main body has an open front surface and a generally box-shaped, recessed rearward profile. Although not shown in Patent Document 1, the housing has a front plate covering the opening. A combustion device is housed within the housing. The combustion device has a combustion chamber and a burner with the flame nozzle located within the combustion chamber to generate high-temperature gas. A heat exchanger is housed above the combustion chamber within the housing. The heat exchanger uses the high-temperature gas to heat water passing through the interior, converting it into hot water.

[0004] As in patent document 1 Figure 1 As shown, a water heater includes: a water supply pipe, a hot water pipe, a water supply connection component, and a hot water supply connection component.

[0005] The water supply pipe and hot water pipe are housed within the casing and connected to the heat exchanger. The water supply connection component and the hot water supply connection component are located on the lower surface of the casing body. The water supply connection component connects the water supply pipe to a water supply path located outside the casing. The hot water supply connection component connects the hot water pipe to a hot water supply path located outside the casing. Additionally, a water flow control unit is provided between the water supply connection component and the water supply pipe to control the flow rate of water flowing through the water supply pipe.

[0006] Patent document 2 discloses an example of a conventional microbubble generator. This microbubble generator is positioned midway in a pipe leading to, for example, a shower fixture or a faucet. The microbubble generator is formed as a generally cylindrical shape with a length in the axial direction greater than its outer width. This microbubble generator is used to generate microbubbles from hot water flowing inside. Furthermore, the greater the axial length of the microbubble generator is than its outer diameter, the easier it is to make the microbubbles generated by the hot water appear smaller.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-55929

[0010] Patent Document 2: Japanese Patent Application Publication No. 2020-171914 Summary of the Invention

[0011] However, the aforementioned technology of housing a microbubble generator within the casing of a conventional water heater was discussed. However, in this case, the microbubble generator, due to its relatively long axial length, tends to increase in size. Furthermore, due to the limitations of its installation location within the casing, which restricts its size or shape, it is easily affected by the combustion device and heat exchanger. Therefore, water heaters housing microbubble generators within the casing require various countermeasures to suppress the effects from the combustion device and heat exchanger, potentially leading to increased manufacturing costs.

[0012] The present invention was made in view of the above-mentioned conventional realities, and its solution is to provide a water heater that can house a microbubble generator within the housing and suppress the increase in manufacturing costs.

[0013] The water heater of the present invention comprises:

[0014] A housing having a box-shaped housing body and a front panel, wherein the housing body has a housing opening that makes the front surface open and is recessed toward the rear, and the front panel covers the housing opening.

[0015] A combustion device, which is housed within the aforementioned housing, generates high-temperature gas and has a combustion chamber and a burner with the flame outlet located within the aforementioned combustion chamber;

[0016] A heat exchanger, housed within the aforementioned housing and positioned above the aforementioned combustion chamber, uses the aforementioned high-temperature gas to heat water passing through the interior, converting it into hot water.

[0017] The water supply pipe is housed in the aforementioned housing and is located on one side of the aforementioned heat exchanger, i.e., the first side, in the width direction orthogonal to the front-back direction and the vertical direction, and extends along the aforementioned vertical direction to connect to the aforementioned heat exchanger.

[0018] A hot water pipe is housed within the aforementioned housing, located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction, and extends along the aforementioned vertical direction to be connected to the aforementioned heat exchanger.

[0019] A water supply connection component, located on the lower surface of the main body of the housing, is used to connect the water supply pipe to the water supply path located outside the housing.

[0020] A hot water supply connection component, located on the lower surface of the aforementioned housing body, is used to connect the aforementioned hot water pipe to a hot water supply path located outside the aforementioned housing; and

[0021] A water flow control unit, disposed between the aforementioned water supply connection component and the aforementioned water supply pipe, is used to control the flow rate of water flowing through the aforementioned water supply pipe; characterized in that,

[0022] The water heater also includes a microbubble generator, which is connected within the housing to one of the water supply pipe and the hot water pipe, i.e., a specific pipe, and is formed as a cylinder with a length in the axial direction greater than its outer width, causing the hot water flowing inside to generate microbubbles.

[0023] The above-mentioned microbubble generator has the following characteristics:

[0024] An inlet, located on one side in the aforementioned axial direction, allows the aforementioned hot water to flow in from the upstream side of the aforementioned specific pipe; and

[0025] The outlet, located on the other side of the aforementioned axial direction, allows the hot water containing the aforementioned microbubbles to flow downstream of the aforementioned specific pipe.

[0026] The aforementioned microbubble generator is located closer to and below the aforementioned flame nozzle.

[0027] In the water heater of the present invention, by utilizing a configuration in which the microbubble generator housed within the casing is positioned closer to and below the flame opening of the burner, the necessity for various countermeasures to suppress the effects of heat conducted from the combustion device and heat exchanger to the microbubble generator can be reduced, such as the necessity to construct the microbubble generator using highly heat-resistant resins or metals. As a result, the water heater can reduce the material and manufacturing costs of the microbubble generator.

[0028] Therefore, the water heater of the present invention can suppress the increase in manufacturing costs by housing the microbubble generator inside the casing.

[0029] The microbubble generator is preferably located on the first side of the heat exchanger in the width direction.

[0030] According to this configuration, the microbubble generator is positioned on the same side as the main pipe in the width direction. Therefore, the water heater can prevent the piping from becoming excessively long between the main pipe and the microbubble generator, thus enabling efficient use of the space within the housing.

[0031] The specific pipe is preferably a hot water pipe. The inlet is preferably located closer to the top than the outlet. Moreover, the outlet is preferably located at the uppermost position in the height direction of the downstream hot water supply flow path from the portion of the hot water pipe connected to the outlet to the hot water supply connection component.

[0032] Based on this configuration, the positional relationship in the vertical direction is: inlet > outlet ≥ downstream hot water supply path. Therefore, when draining the microbubble generator, there is no need to set up a separate drainage circuit; the water heater can drain from the hot water supply connection component.

[0033] In the above case, the microbubble generator is preferably located near the top of the specific water volume control unit.

[0034] Based on this configuration, by disassembling the portion of the microbubble generator located downstream of the hot water pipe, it is possible to easily access or remove the water flow control unit. As a result, the water heater achieves improved maintainability.

[0035] The specific pipe is preferably a hot water pipe. Furthermore, when viewing the microbubble generator along its width, the axial direction is preferably inclined such that the inlet is located closer to the top than the outlet.

[0036] Based on this configuration, it is possible to appropriately position the relatively long microbubble generator along its axis closer to the bottom than the burner's flame opening. Furthermore, since the microbubble generator is tilted with its inlet located closer to the top than its outlet, drainage within the microbubble generator can be easily implemented. As a result, the water heater achieves improved freeze resistance.

[0037] In the above case, one of the inlet and outlet is preferably located closer to the rear than the other of the inlet and outlet, and is open in the vertical direction.

[0038] According to this configuration, when the inlet is located closer to the rear than the outlet, the inlet opens upwards in the vertical direction. Therefore, the water heater is configured such that the connection between the upstream side of the hot water pipe and the inlet can be easily observed from the front, and the connection can be easily reached through the housing opening. Furthermore, when the outlet is located closer to the rear than the inlet, the outlet opens downwards in the vertical direction. Therefore, the water heater is configured such that the connection between the downstream side of the hot water pipe and the outlet can be easily observed from the front, and the connection can be easily reached through the housing opening. As a result, the water heater achieves further improvements in maintainability.

[0039] Furthermore, in the above-mentioned case, the outlet is preferably located closer to the front than the inlet.

[0040] From an assembly efficiency perspective, in most cases, the hot water supply connection port of the hot water supply connection component, which connects to the hot water pipe, is open towards the front surface of the housing. Therefore, by positioning the outlet closer to the front than the inlet, the downstream side of the hot water pipe connected to the outlet can be easily routed back to the hot water supply interface of the hot water supply connection component. As a result, this water heater achieves improved assembly efficiency and manufacturability, as well as reduced manufacturing costs.

[0041] The specific pipe is preferably a water supply pipe. The outlet is preferably located above the inlet. Moreover, the inlet is preferably located at the uppermost position in the vertical direction of the upstream water supply flow path from the water supply connection component to the portion of the water supply pipe connected to the inlet.

[0042] Based on this configuration, the positional relationship in the vertical direction is: outlet > inlet ≥ upstream hot water supply path. Therefore, when draining the microbubble generator, there is no need to set up a separate drainage circuit; the water heater can drain from the hot water supply connection component.

[0043] In the above case, the microbubble generator is preferably located near the top of the specific water volume control unit.

[0044] According to this configuration, by disassembling the portion of the water supply pipe located upstream of the microbubble generator, it is possible to easily access or remove the water flow control unit. As a result, the water heater can achieve improved maintainability.

[0045] The specific pipe is preferably a water supply pipe. Moreover, it is preferable that when the microbubble generator is viewed along its width, the axial direction is inclined such that the outlet is located closer to the top than the inlet.

[0046] Based on this configuration, it is possible to appropriately position the relatively long microbubble generator along its axis closer to and below the burner's flame opening. Furthermore, since the microbubble generator is tilted with its outlet positioned closer to and above the inlet, drainage within the microbubble generator can be easily implemented. As a result, the water heater achieves improved freeze resistance.

[0047] In the above case, it is preferable that one of the inlet and outlet is located closer to the rear than the other of the inlet and outlet, and is open in the vertical direction.

[0048] According to this configuration, when the inlet is located closer to the rear than the outlet, the inlet opens downwards in the vertical direction. Therefore, the water heater is configured such that the connection between the upstream side of the water supply pipe and the inlet is easily visible from the front, and the connection can be easily reached through the housing opening. Furthermore, when the outlet is located further rear than the inlet, the outlet opens upwards in the vertical direction. Therefore, the water heater is configured such that the connection between the downstream side of the water supply pipe and the outlet is easily visible from the front, and the connection can be easily reached through the housing opening. As a result, the water heater achieves further improvements in maintainability.

[0049] Furthermore, in the above-mentioned case, it is preferable that the inlet is located closer to the front than the outlet.

[0050] From an assembly and workability perspective, in most cases, the water supply connection port of the water flow control unit, which connects to the water supply pipe, is open towards the front surface of the casing. Therefore, by configuring the inlet to be closer to the front than the outlet, the upstream side of the water supply pipe connected to the inlet can be easily routed back to the water supply connection port of the water flow control unit. As a result, this water heater achieves improved assembly and workability, as well as reduced manufacturing costs.

[0051] Preferably, the microbubble generator comprises: an inlet portion having an inlet and connected to the upstream side of a specific pipe; an outlet portion having an outlet and connected to the downstream side of the specific pipe; and a main body portion connected to the inlet portion on one side in the axial direction and to the outlet portion on the other side in the axial direction, thereby generating microbubbles from the hot water flowing inside. Furthermore, it is preferable that the inlet portion, the outlet portion, and the main body portion are each constructed using different devices.

[0052] Based on this configuration, by pre-preparing various inlet and outlet sections of different shapes, and by using the appropriately selected inlet and outlet sections, various connection / installation methods, such as vertical installation or inclined installation, can easily handle inflow and outflow in the vertical direction.

[0053] According to the water heater of the present invention, the configuration in which the microbubble generator is housed within the casing can suppress the increase in manufacturing costs. Attached Figure Description

[0054] Figure 1 This is a perspective view of the water heater in Example 1.

[0055] Figure 2 This is a perspective view showing the state of the water heater in Embodiment 1 after the front panel has been removed.

[0056] Figure 3 This is a schematic diagram of the water heater in Example 1.

[0057] Figure 4 This is a partial perspective view showing the combustion chamber, flame nozzle, microbubble generator, etc. of the water heater in Example 1.

[0058] Figure 5 This refers to the water heater of Example 1, from Figure 2 A three-dimensional view of the state after the main body of the unicorn shell, combustion fan, first combustion device, second combustion device, first main heat exchanger, first auxiliary heat exchanger, second main heat exchanger, and second auxiliary heat exchanger have been removed.

[0059] Figure 6 This is an exploded perspective view showing the hot water pipe, microbubble generator, hot water supply connection component, hot water injection control unit, water supply connection component, water volume control unit, bypass pipe, etc. of the water heater in Embodiment 1.

[0060] Figure 7 This is a side view showing the hot water pipe, bypass pipe, microbubble generator, water supply connection component, hot water supply connection component, water volume control unit, hot water injection control unit, etc. of the water heater in Embodiment 1.

[0061] Figure 8 This is an exploded perspective view showing the microbubble generator of the water heater in Example 1.

[0062] Figure 9 This is a schematic diagram of the water heater in Example 2.

[0063] Figure 10 This is a side view showing the water supply pipe, microbubble generator, water supply connection component, hot water supply connection component, water volume control unit, hot water injection control unit, etc. of the water heater in Embodiment 2.

[0064] Explanation of reference numerals in the attached figures

[0065] 1, 2: Water heater; 4: Bathtub

[0066] 8: Casing 8A: Casing Body

[0067] 8B: Front panel; 8B1: Exhaust opening

[0068] 8B2: External gas inlet opening; 8H: Shell opening

[0069] 9, 209: Microbubble generator; 10: Water supply connection components.

[0070] 10S: Water supply path; 20: Hot water supply connection components

[0071] 20H1: Hot water supply interface; 20S: Hot water supply path

[0072] 30F: Combustion fan; 30G: Gas supply pipe

[0073] 30V: Existing gas solenoid valve; 30P: Gas proportional valve

[0074] 31, 32: Combustion devices (31 First combustion device, 32 Second combustion device)

[0075] 31B, 32B: Burners; 31C, 32C: Combustion chambers

[0076] 31F, 32F: Burner nozzles; 31P: Branch pipe

[0077] 31V: First gas solenoid valve; 33A, 33B, 33C: Partition plate

[0078] 40B: Outer casing; 40C: Tank body

[0079] 41A: First main heat exchanger; 41B: First auxiliary heat exchanger

[0080] 42A: Second main heat exchanger; 42B: Second auxiliary heat exchanger

[0081] 41A1, 42A1: Heat transfer tubes; 41B1, 42B1: Heat transfer tubes

[0082] 48: Neutralizer; 48P: Drain pipe

[0083] 49: Vent outlet 50: Water volume control unit

[0084] 50H1: Water supply connection port; 50H2: Bypass connection port

[0085] 51: Bypass servo mechanism; 52: Water volume servo mechanism

[0086] 60: Hot water injection control unit; 60H1: Hot water injection connection port

[0087] 61: Hot water injection solenoid valve; 62A, 62B: Check valve

[0088] 63: Atmospheric venting valve; 69: Water pump

[0089] 73: Bathtub return connection component; 73A: External piping

[0090] 74: Bathtub process connection component 74A: External piping

[0091] 90, 290: Main body; 91, 291: Inflow section

[0092] 91A, 92A: Fitting part; 91B, 92B: Screw

[0093] 91C: Chuck; 91H, 291H: Inlet / Outlet

[0094] 92, 292: Outflow section; 92C: Clamp.

[0095] 92H, 292H: Outlet; 93: Venturi tube component

[0096] 93A: Venturi tube flow path; 94: Stirring component

[0097] 94A: Blade; P1, P201: Water supply pipe

[0098] P2, P202: Hot water pipe; X9: Axis

[0099] P2D, P201D: Downstream side of hot water pipe

[0100] P2U, P201U: Upstream side of hot water pipe

[0101] P3: Bathtub return piping P4: Bathtub progress piping

[0102] P6: Hot water supply pipe; P7: Narrow connecting pipe

[0103] P8: Connecting pipe; P11: Intermediate water supply pipe

[0104] P12: Narrow connecting pipe; P21: Bypass pipe

[0105] P31: Intermediate piping; P32: Narrow connecting pipe Detailed Implementation

[0106] Hereinafter, with reference to the accompanying drawings, embodiments 1 and 2, which embody the present invention, will be described.

[0107] (Example 1)

[0108] like Figure 1 As shown, the water heater 1 of Embodiment 1 is an example of a specific embodiment of the water heater of the present invention. In the following description, the front panel 8B side of the housing 8 of the water heater 1, i.e. Figure 1 The front side of the paper is designated as the front of water heater 1. Figure 1 The left side of the paper is defined as the left side of water heater 1. Figure 1 The upper part of the paper specifies that it is above water heater 1. Furthermore, Figure 2 The subsequent diagrams show all directions—front / back, left / right, and up / down—that are all related to... Figure 1 The components of water heater 1 will be described below.

[0109] <Shell>

[0110] like Figure 1 As shown, the water heater 1 has a housing 8. The housing 8 has a housing body 8A and a front panel 8B.

[0111] like Figure 2 As shown, the main body 8A of the housing is a generally box-shaped structure with a housing opening 8H on the front surface that is open and recessed towards the rear. Figure 1 As shown, the front panel 8B is a roughly rectangular flat plate and covers the housing opening 8H. The housing body 8A and the front panel 8B define an interior space that is roughly cuboid in shape.

[0112] The width direction of the housing 8 is orthogonal to the front-back and vertical directions, and in this embodiment, it is consistent with the left-right direction. The water heater 1 is typically mounted on the pipe axis of an apartment building. Therefore, the size and shape of the housing 8 in the vertical, front-back, and width directions are limited in such a way that it is housed within the pipe axis.

[0113] An exhaust opening 8B1 is provided through the upper end of the front panel 8B, exposing the exhaust port 49 described later. An external gas inlet opening 8B2 is provided through the lower end of the front panel 8B for introducing external gas into the housing 8.

[0114] <Combustion fan, first combustion device and second combustion device>

[0115] like Figure 2 as well as Figure 3 As shown, the water heater 1 includes: a combustion fan 30F, a first combustion device 31, and a second combustion device 32. The first combustion device 31 and the second combustion device 32 are examples of the "combustion device" of the present invention.

[0116] The combustion fan 30F is housed in the lower part of the housing 8. The combustion fan 30F supplies combustion air to the first combustion device 31 and the second combustion device 32.

[0117] The first combustion device 31 and the second combustion device 32 are housed in the middle part of the housing 8 in the vertical direction. Figure 3 as well as Figure 4 As shown, the second combustion device 32 is located to the left of the first combustion device 31 and is smaller than the first combustion device 31.

[0118] The first combustion device 31 includes a combustion chamber 31C and a burner 31B. The second combustion device 32 includes a combustion chamber 32C and a burner 32B. The combustion chamber 31C and the burner 31B are connected by a communication channel. Figure 3 The partition plate 33A shown is used to separate them.

[0119] exist Figure 4 The diagram of partition plate 33A is omitted. In the first combustion device 31, the flame openings 31F of burner 31B are located within combustion chamber 31C, and multiple flame openings are arranged in the front-back and left-right directions. In the second combustion device 32, the flame openings 32F of burner 32B are located within combustion chamber 32C, and multiple flame openings are arranged in the front-back and left-right directions.

[0120] The height of the flame opening 31F of burner 31B is the same as the height of the flame opening 32F of burner 32B. Figure 7In the diagram, height H1 represents the height of the flame openings 31F and 32F of burners 31B and 32B.

[0121] like Figure 3 As shown, in the first combustion device 31, fuel gas such as city gas or liquefied petroleum gas is supplied from a gas supply source (not shown) located outside the housing 8, via a gas supply pipe 30G, an existing gas solenoid valve 30V, a gas proportional valve 30P, a branch pipe 31P, and a first gas solenoid valve 31V, toward the burner 31B. The burner 31B discharges the fuel gas from the flame port 31F for combustion. Accordingly, the first combustion device 31 generates combustion exhaust gas, i.e., high-temperature gas.

[0122] In the second combustion device 32, fuel gas is supplied from a gas supply source (not shown) located outside the housing 8, via a gas supply pipe 30G, an existing gas solenoid valve 30V, a gas proportional valve 30P, a branch pipe 32P, and a second gas solenoid valve 32V, toward the burner 32B. The burner 32B discharges the fuel gas from the flame port 32F for combustion. Accordingly, the second combustion device 32 generates combustion exhaust gas, i.e., high-temperature gas.

[0123] <First main heat exchanger, first auxiliary heat exchanger, second main heat exchanger, and second auxiliary heat exchanger>

[0124] like Figure 2 as well as Figure 3 As shown, the water heater 1 includes a first main heat exchanger 41A, a first auxiliary heat exchanger 41B, a second main heat exchanger 42A, and a second auxiliary heat exchanger 42B.

[0125] The first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B are examples of the "heat exchangers" of the present invention.

[0126] like Figure 3 As shown, the second combustion device 32, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B are used to perform reheating of the bathtub 4 installed in the bathroom. That is, the water heater 1 is a bathtub water heater.

[0127] The first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B are housed in the upper part of the casing 8.

[0128] The first main heat exchanger 41A is located above the combustion chamber 31C of the first combustion device 31. The second main heat exchanger 42A is located above the combustion chamber 32C of the second combustion device 32.

[0129] The first main heat exchanger 41A and the second main heat exchanger 42A share a common... Figure 2 The outer casing 40B shown is through Figure 3 The partition plate 33B shown is used to separate them.

[0130] The first auxiliary heat exchanger 41B is located closer to the top than the first main heat exchanger 41A. The second auxiliary heat exchanger 42B is located closer to the top than the second main heat exchanger 42A.

[0131] The first heat exchanger 41B and the second heat exchanger 42B share the same... Figure 2 The tank shown is 40C, and it is through Figure 3 The partition plate 33C shown is used to separate them.

[0132] like Figure 2 As shown, the tank 40C has an exhaust port 49. The exhaust port 49 protrudes forward from the front surface of the tank 40C. Figure 1 As shown, the exhaust port 49 passes through the exhaust opening 8B1 of the front panel 8B and is exposed to the outside of the housing 8.

[0133] The high-temperature gas generated by the first combustion device 31 and the second combustion device 32 rises inside the outer casing 40B and the tank 40C, and is discharged from the exhaust port 49 to the outside of the shell 8.

[0134] like Figure 3 As shown, the first main heat exchanger 41A has heat transfer tubes 41A1. Although in Figure 3 The heat transfer tube 41A1 is illustrated in a simplified manner. However, the heat transfer tube 41A1 is serpentine and includes multiple straight sections, as well as multiple folded sections that turn back into arcs to connect the straight sections. Each straight section of the heat transfer tube 41A1 has multiple heat transfer fins.

[0135] The first main heat exchanger 41A exchanges heat between the water flowing in the heat transfer tube 41A1 and the high-temperature gas generated by the first combustion device 31, absorbing the sensible heat of the high-temperature gas.

[0136] The first heat exchanger 41B has heat transfer tubes 41B1. Although in Figure 3 The heat transfer tube 41B1 is illustrated simply. However, the heat transfer tube 41B1 is a serpentine bellows, which includes multiple straight sections and multiple folded sections that turn back into arcs to connect the straight sections.

[0137] The first heat exchanger 41B exchanges heat between the water flowing in the heat transfer tube 41B1 and the high-temperature gas generated by the first combustion device 31, absorbing the latent heat of the high-temperature gas.

[0138] The second main heat exchanger 42A has a heat transfer tube 42A1 with the same structure as the heat transfer tube 41A1. The second main heat exchanger 42A exchanges heat between the water flowing in the heat transfer tube 42A1 and the high-temperature gas generated by the second combustion device 32, absorbing the sensible heat of the high-temperature gas.

[0139] The second heat exchanger 42B has a heat transfer tube 42B1 with the same configuration as the heat transfer tube 41B1. The second heat exchanger 42B exchanges heat between the water flowing in the heat transfer tube 42B1 and the high-temperature gas generated by the second combustion device 32, absorbing the latent heat of the high-temperature gas.

[0140] Thus, the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B respectively heat the water passing through them with the help of high-temperature gas and convert it into hot water.

[0141] like Figure 2 as well as Figure 3 As shown, the upper end of a drain pipe 48P is connected to the bottom wall of the tank 40C. The lower end of the drain pipe 48P is connected to a neutralizer 48. The wastewater generated by condensation inside the tank 40C is introduced into the neutralizer 48 through the drain pipe 48P. The neutralizer 48 neutralizes the wastewater with the aid of a neutralizing agent, and then discharges the wastewater to the outside of the housing 8.

[0142] <Water supply pipes, intermediate water supply pipes, hot water pipes, and bypass pipes>

[0143] like Figures 2 to 5 As shown, the water heater 1 includes: a water supply pipe P1, an intermediate water supply pipe P11, a hot water pipe P2, and a bypass pipe P21. The hot water pipe P2 is an example of a "specific pipe" of the present invention.

[0144] Water supply pipe P1, intermediate water supply pipe P11, hot water pipe P2, and bypass pipe P21 are housed within housing 8. Water supply pipe P1, intermediate water supply pipe P11, hot water pipe P2, and bypass pipe P21 are located on one side (i.e., the right side) of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction.

[0145] In addition, the water supply pipe P1, the intermediate water supply pipe P11, the hot water pipe P2, and the bypass pipe P21 are located to the right of the first combustion device 31 and the second combustion device 32 in the width direction.

[0146] like Figure 3 as well as Figure 5As shown, the upstream end of the water supply pipe P1 is connected to the water supply connection port 50H1 of the water flow control unit 50 (described later). The downstream end of the water supply pipe P1 is located above the upstream end of the water supply pipe P1. The downstream end of the water supply pipe P1 is connected to the inlet of the heat transfer tube 41B1 of the first auxiliary heat exchanger 41B. The water supply pipe P1 extends in a vertical direction while making multiple bends between the upstream and downstream ends.

[0147] The upstream end of the intermediate water supply pipe P11 is connected to the outlet of the heat transfer tube 41B1 of the first auxiliary heat exchanger 41B. The downstream end of the intermediate water supply pipe P11 is located below the upstream end of the intermediate water supply pipe P11. The downstream end of the intermediate water supply pipe P11 is connected to the inlet of the heat transfer tube 41A1 of the first main heat exchanger 41A.

[0148] The middle section of the water supply pipe P1 is connected to the middle section of the intermediate water supply pipe P11 via the narrow connecting pipe P12.

[0149] The upstream end of hot water pipe P2 is connected to the outlet of heat transfer pipe 41A1 of the first main heat exchanger 41A. The downstream end of hot water pipe P2 is located below the upstream end of hot water pipe P2. The downstream end of hot water pipe P2 is connected to the hot water supply interface 20H1 of the hot water supply connection component 20 (described later). Hot water pipe P2 extends in a vertical direction while bending multiple times between the upstream and downstream ends. A microbubble generator 9 (described later) is connected midway through hot water pipe P2.

[0150] The upstream end of the bypass pipe P21 is connected to the bypass connection port 50H2 of the water flow control unit 50 (described later). The downstream end of the bypass pipe P21 is located above the upstream end of the bypass pipe P21. The downstream end of the bypass pipe P21 is connected near the upstream end of the hot water pipe P2.

[0151] <Water supply connection components, hot water supply connection components, water volume control unit, and hot water injection control unit>

[0152] like Figure 2 , Figure 3 as well as Figure 5 As shown, the water heater 1 includes: a water supply connection component 10, a hot water supply connection component 20, a water volume control unit 50, and a hot water injection control unit 60.

[0153] The water supply connection component 10 is located on the right side of the lower surface of the housing body 8A. For example... Figure 3 As shown, the portion of the water supply connection component 10 that protrudes downward from the lower surface of the housing body 8A has: a connection portion that connects the water supply pipe P1 to the water supply path 10S located outside the housing 8, and a water filter that also serves as a drain plug.

[0154] The portion of the water supply connection component 10 that protrudes upward from the lower surface of the housing body 8A is connected to the water volume control unit 50.

[0155] like Figure 5 As shown, the water flow control unit 50 has a water supply connection port 50H1 connected to the upstream end of the water supply pipe P1. That is, the water flow control unit 50 is provided between the water supply connection component 10 and the water supply pipe P1. In addition, the water flow control unit 50 has a bypass connection port 50H2 connected to the upstream end of the bypass pipe P21.

[0156] like Figure 3 As shown, the water volume control unit 50 has a bypass servo mechanism 51 and a water volume servo mechanism 52.

[0157] The bypass servo mechanism 51 switches between a bypass closed state and a bypass open state. In the bypass closed state, the water supplied to the water volume control unit 50 is directed only to the water supply pipe P1. In the bypass open state, the water supplied to the water volume control unit 50 is directed not only to the water supply pipe P1 but also to the bypass pipe P21.

[0158] When the bypass servo mechanism 51 is in the bypass closed state, the water flow servo mechanism 52 controls the flow rate of water flowing in the water supply pipe P1. On the other hand, when the bypass servo mechanism 51 is in the bypass open state, the water flow servo mechanism 52 controls the flow rate of water flowing in the water supply pipe P1 and the bypass pipe P21.

[0159] like Figure 2 , Figure 3 as well as Figure 5 As shown, the hot water supply connection component 20 is the right portion of the lower surface of the housing body 8A, and is located to the right and rear of the water supply connection component 10. Figure 3 As shown, the portion of the hot water supply connection component 20 that protrudes downward from the lower surface of the housing body 8A includes: a connection for connecting the hot water pipe P2 to the hot water supply path 20S located outside the housing 8, a water hammer buffer valve, and a pressure safety valve that also serves as a drain plug.

[0160] like Figure 5 As shown, the portion of the hot water supply connection component 20 that protrudes upward from the lower surface of the housing body 8A branches into a T-shape. At the front end of the portion protruding forward from its branch, the hot water supply connection component 20 has a hot water supply interface 20H1 that connects to the downstream end of the hot water pipe P2.

[0161] The portion of the hot water supply connection component 20 that protrudes upward from its branch is connected to the hot water injection control unit 60.

[0162] like Figure 3As shown, the hot water injection control unit 60 includes: a hot water injection solenoid valve 61, check valves 62A and 62B, and an atmospheric release valve 63.

[0163] like Figure 5 as well as Figure 6 As shown, one end of the hot water supply pipe P6 is connected to the hot water inlet 60H1 of the hot water inlet control unit 60. Figure 3 as well as Figure 5 As shown, the other end of the hot water supply pipe P6 is connected to the upstream portion of the bathtub return pipe P3 described later, which is the water pump 69.

[0164] The hot water injection solenoid valve 61 switches between a hot water injection open state and a hot water injection closed state. In the hot water injection open state, water supplied to the hot water injection control unit 60 is supplied to the hot water injection supply pipe P6. In the hot water injection closed state, water supplied to the hot water injection control unit 60 is not supplied to the hot water injection supply pipe P6.

[0165] The atmospheric release valve 63 of the hot water injection control unit 60 and the upstream portion of the specific water volume servo mechanism 52 of the water volume control unit 50 are connected via a thin connecting pipe P7. Furthermore, the atmospheric release valve 63 is connected to the drain side of the neutralizer 48 via a connecting pipe P8.

[0166] <Bathtub process piping, bathtub return piping, and water pump>

[0167] like Figure 3 as well as Figure 5 As shown, the water heater 1 includes: bathtub return piping P3, intermediate piping P31, bathtub process piping P4, and water pump 69.

[0168] The bathtub return piping P3, intermediate piping P31, bathtub process piping P4, and water pump 69 are housed within the casing 8. The bathtub return piping P3, intermediate piping P31, bathtub process piping P4, and water pump 69 are located on the other side (i.e., the left side) of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction.

[0169] The upstream end of the bathtub return pipe P3 is connected to the bathtub return connection component 73 located on the left side of the lower surface of the main body 8A. The bathtub return connection component 73 is connected to the suction port of the bathtub 4 via the external pipe 73A.

[0170] The downstream end of the bathtub return piping P3 is located above the upstream end of the bathtub return piping P3. The downstream end of the bathtub return piping P3 is connected to the inlet of the heat transfer tube 42B1 of the second auxiliary heat exchanger 42B.

[0171] A water pump 69 is connected midway through the return pipe P3 of the bathtub, and the other end of the hot water supply pipe P6 is connected upstream of the water pump 69.

[0172] The upstream end of intermediate piping P31 is connected to the outlet of heat transfer tube 42B1 of the second auxiliary heat exchanger 42B. The downstream end of intermediate piping P31 is located closer to the bottom than the upstream end of intermediate piping P31. The downstream end of intermediate piping P31 is connected to the inlet of heat transfer tube 42A1 of the second main heat exchanger 42A.

[0173] The middle section of the bathtub return piping P3 is connected to the middle section of the intermediate piping P31 via a narrow connecting pipe P32.

[0174] The upstream end of the bathtub process piping P4 is connected to the outlet of the heat transfer tube 42A1 of the second main heat exchanger 42A. The downstream end of the bathtub process piping P4 is located closer to the bottom than the upstream end of the bathtub process piping P4. The downstream end of the bathtub process piping P4 is connected to the bathtub process connection component 74 located on the left part of the lower surface of the shell body 8A. The bathtub process connection component 74 is connected to the hot water outlet of the bathtub 4 via the external piping 74A.

[0175] <Microbubble Generator>

[0176] like Figure 2 ~ Figure 7 As shown, the water heater 1 also includes a microbubble generator 9. The microbubble generator 9 is located inside the housing 8 and connected to the middle of the hot water pipe P2. In the width direction, the microbubble generator 9 is located on the first side, i.e. the right side, of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B.

[0177] Furthermore, the microbubble generator 9 is located to the right of the first combustion device 31 and the second combustion device 32 in the width direction.

[0178] The microbubble generator 9 is a device that generates microbubbles in hot water flowing inside. These microbubbles originate from air or other substances dissolved in the hot water and do not require an external gas supply.

[0179] In this embodiment, the microbubble generator 9 is a so-called "micro fine bubble generator" that generates microbubbles containing bubbles with a diameter of less than 1 μm from the hot water flowing inside. Therefore, the microbubble generator 9 has the configuration described below.

[0180] like Figure 8As shown, the microbubble generator 9 includes a main body 90, an inlet 91, and an outlet 92. The main body 90, inlet 91, and outlet 92 are each constructed using different components. In this embodiment, the main body 90, inlet 91, and outlet 92 are all made of heat-resistant resin suitable for high-temperature hot water.

[0181] The main body 90 is generally cylindrical with the axis X9 as its center. The main body 90 is connected to the inflow portion 91 on one side in the direction of the axis X9, and to the outflow portion 92 on the other side in the direction of the axis X9.

[0182] The inflow portion 91 has a fitting portion 91A that engages with the main body portion 90 and is connected to the main body portion 90 by a plurality of screws 91B. The inflow portion 91 bends upward from the fitting portion 91A. An inlet 91H is formed at the end of the inflow portion 91 opposite to the fitting portion 91A, and the inlet 91H is centered on the axis intersecting the axis X9.

[0183] The outlet 92 has a fitting portion 92A that fits into the main body 90 and is connected to the main body 90 by a plurality of screws 92B. An outlet 92H is formed at the end of the outlet 92 opposite to the fitting portion 92A, and the outlet 92H is centered on the axis X9.

[0184] The main body 90 houses a venturi tube component 93 and multiple stirring components 94. The venturi tube component 93 and each stirring component 94 are made of heat-resistant resin suitable for high-temperature hot water. The venturi tube component 93 is located on the inlet side 91, and each stirring component 94 is located on the outlet side 92.

[0185] A plurality of Venturi flow paths 93A are formed in the Venturi tube component 93. One Venturi flow path 93A is centered on the axis X9. The remaining Venturi flow paths 93A are arranged at equal intervals in the circumferential direction of the axis X9 and extend parallel to the axis X9. Each Venturi flow path 93A has: a throttling section in which the flow is throttled, a narrowing flow path that narrows from the inlet 91 side toward the throttling section, and an expanding flow path that widens from the throttling section toward the outlet 92 side.

[0186] Each stirring component 94 has multiple blades 94A. Each blade 94A is arranged at equal intervals in the circumferential direction of the axis X9 and is inclined relative to the axis X9.

[0187] The main body 90, through the Venturi tube component 93 and each stirring component 94, generates microbubbles containing bubbles with a diameter of less than 1 μm in the hot water flowing inside. In particular, by increasing the number of stirring components 94 arranged in series, bubbles with a diameter of less than 1 μm can be easily generated, and correspondingly, the length L90 of the main body 90 in the axial X9 direction becomes longer.

[0188] The length L90 of the main body 90 in the axial x9 direction is greater than the outer diameter D90 of the main body 90. That is, the microbubble generator 9 is formed as a generally cylindrical shape (approximately cylindrical) in which the length in the axial x9 direction is greater than the outer width (outer diameter). In this embodiment, the length L90 is more than twice the outer diameter D90.

[0189] like Figure 4 ~ Figure 7 As shown, the microbubble generator 9 is connected to the middle of the hot water pipe P2 with its axis X9 tilted. When the microbubble generator 9 is viewed along its width, the axis X9 is tilted such that the inlet 91H is located closer to the outlet 92H than the outlet 92H. In this embodiment, the axis X9 extends approximately parallel to the front-back direction and the up-down direction.

[0190] In this configuration, one side along the axis X9 is the rear, and the other side along the axis X9 is the front. The outlet 92H is located closer to the front than the inlet 91H. The inlet 91H is located closer to the rear than the outlet 92H and opens vertically upwards.

[0191] The inlet 91H is located on one side in the direction of the axis X9, that is, closer to the rear than the main body 90, and is connected to the upstream side P2U of the hot water pipe P2. Hot water flows into the inlet 91H from the upstream side P2U of the hot water pipe P2.

[0192] Outlet 92H is located on the other side of the axis X9, that is, closer to the front than the main body 90, and is connected to the downstream side P2D of hot water pipe P2. Outlet 92H allows hot water containing microbubbles to flow out towards the downstream side P2D of hot water pipe P2.

[0193] like Figure 4 As shown, the upstream side P2U of the hot water pipe P2 and the inlet 91 are fixed together by a metal clamp 91C using a single action. Similarly, the downstream side P2D of the hot water pipe P2 and the outlet 92 are fixed together by a metal clamp 92C using a single action.

[0194] exist Figure 4 The diagram shows flame holes 31F and 32F. Figure 7In the diagram, height H1 represents the height of flame openings 31F and 32F. The microbubble generator 9 is located closer to the bottom of flame openings 31F and 32F of burners 31B and 32B.

[0195] exist Figure 7 In this context, height H2 represents the height of the downstream hot water supply flow path from the portion of the downstream side P2D of the hot water pipe P2 connected to the outlet 92H to the hot water supply connection component 20. The outlet 92H is located at a height above the height H2 of the downstream hot water supply flow path.

[0196] exist Figure 7 In this context, height H3 represents the height of the internal flow path of the water flow control unit 50. The microbubble generator 9 is located slightly above the water flow control unit 50, and more specifically, it is located slightly above the height H3 of the internal flow path of the hot water injection control unit 60.

[0197] <Hot water supply operation>

[0198] When a user operates to supply hot water, such as opening the hot water outlet valve of a mixing valve in the kitchen, or a mixing valve or shower in the bathroom, the bypass servo mechanism 51 is normally in the bypass closed state, and the first combustion device 31 starts combustion to generate high-temperature gas. However, for special purposes such as maintaining the hot water outlet temperature from the first main heat exchanger 41A at a high temperature, the bypass servo mechanism 51 may sometimes be in the bypass open state.

[0199] Water supplied from a source not shown in the diagram passes through the water supply path 10S, the water supply connection component 10, the water flow control unit 50, the water supply pipe P1, the heat transfer tube 41B1 of the first auxiliary heat exchanger 41B, the intermediate water supply pipe P11, and the heat transfer tube 41A1 of the first main heat exchanger 41A. At this time, the water is heated to hot water by the first auxiliary heat exchanger 41B and the first main heat exchanger 41A. Furthermore, this hot water passes through the hot water pipe P2, and along the way, a microbubble generator 9 generates microbubbles containing bubbles with a diameter of less than 1 μm.

[0200] In addition, the hot water flows out from the hot water outlet plug of the hot water supply terminal in a state containing microbubbles through the hot water supply connection component 20 and the hot water supply path 20S.

[0201] <Hot water filling action>

[0202] When a user performs a hot water filling operation, for example, by pressing the hot water filling button on a hot water supply remote control located in the kitchen or bathroom, the first combustion device 31 starts combustion to generate high-temperature gas. The bypass servo mechanism 51 switches to the bypass open state depending on the situation. The hot water filling solenoid valve 61 then switches to the hot water filling open state. The water pump 69 stops.

[0203] Water supplied from a water source not shown flows into hot water via water supply pipe P1, becoming hot water in the same way as the hot water supply operation, and flows into hot water pipe P2. In addition, when the bypass servo mechanism 51 is in the bypass open state, a portion of the water supplied from the water source not shown flows into hot water pipe P2 via bypass pipe P21.

[0204] Furthermore, the hot water passes through the hot water pipe P2, and microbubbles containing bubbles with a diameter of less than 1 μm are generated midway using a microbubble generator 9.

[0205] Furthermore, the hot water flows from the hot water supply connection component 20, the hot water injection control unit 60, and the hot water injection supply pipe P6 into the bathtub return pipe P3, at the position upstream of the water pump 69. Also, a portion of the hot water reaches the bathtub 4 through the water pump 69, the heat transfer pipe 42B1 of the second auxiliary heat exchanger 42B, the intermediate pipe P31, the heat transfer pipe 42A1 of the second main heat exchanger 42A, the bathtub process pipe P4, the bathtub process connection component 74, and the external pipe 74A. The remaining portion of the hot water reaches the bathtub 4 through the bathtub return pipe P3, the bathtub return connection component 73, and the external pipe 73A. Thus, the hot water, passing through two paths, is retained in the bathtub 4 in a state containing tiny air bubbles.

[0206] <Reheating action>

[0207] When the user performs a reheating operation, for example, by pressing the reheat button on a hot water supply remote control located in the kitchen or bathroom, the second combustion device 32 starts combustion to generate high-temperature gas. The hot water injection solenoid valve 61 is then in the hot water injection closed state.

[0208] The water pump 69 operates, causing the hot water stored in the bathtub 4 to circulate in the following order: external piping 73A, bathtub return connection 73, bathtub return piping P3, heat transfer tube 42B1 of the second auxiliary heat exchanger 42B, intermediate piping P31, heat transfer tube 42A1 of the second main heat exchanger 42A, bathtub process piping P4, bathtub process connection 74, and external piping 74A. As a result, the circulated hot water is reheated using the second auxiliary heat exchanger 42B and the second main heat exchanger 42A.

[0209] <Efficacy and Function>

[0210] In the water heater 1 of Example 1, as Figure 4 as well as Figure 7 As shown, by positioning the microbubble generator 9, housed within the casing 8, closer to and below the flame ports 31F and 32F of the burners 31B and 32B, the necessity for various countermeasures to suppress the effects of heat conducted from the first combustion device 31, the second combustion device 32, the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B to the microbubble generator 9 can be reduced. For example, the necessity for constructing the microbubble generator 9 using highly heat-resistant resin or metal can be reduced. As a result, the water heater 1 can reduce the material and processing costs of the microbubble generator 9.

[0211] Therefore, the water heater 1 of Embodiment 1 can suppress the increase in manufacturing costs by housing the microbubble generator 9 within the housing 8.

[0212] Additionally, in this water heater 1, such as Figure 2 ~ Figure 4 As shown, the microbubble generator 9 is located on the first side, i.e., the right side, of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction. With this configuration, the microbubble generator 9 is positioned on the same side as the hot water pipe P2 in the width direction. Therefore, the water heater 1 can prevent the piping from becoming excessively long between the hot water pipe P2 and the microbubble generator 9, thus effectively utilizing the space within the housing 8.

[0213] Furthermore, in this water heater 1, such as Figure 7 As shown, the inlet 91H is located closer to the top than the outlet 92H. Furthermore, the outlet 92H is located at a height H2 above the downstream hot water supply flow path from the portion of the hot water pipe P2D connected to the outlet 92H to the hot water supply connection component 20. Based on this configuration, the vertical positional relationship is: inlet 91H > outlet 92H ≥ height H2 of the downstream hot water supply flow path. Therefore, when draining the microbubble generator 9, there is no need to install a separate drainage circuit; the water heater 1 can drain from the hot water supply connection component 20.

[0214] Furthermore, in this water heater 1, the microbubble generator 9 is located closer to the upper part of the water flow control unit 50, more specifically, it is located closer to the upper part of the internal flow path H3 of the hot water injection control unit 60. With this configuration, by removing the hot water pipe P2 located downstream of the microbubble generator 9, i.e., downstream side P2D of the hot water pipe P2, it is possible to easily access or remove the water flow control unit 50. As a result, the water heater 1 achieves improved maintainability.

[0215] Furthermore, in this water heater 1, when the microbubble generator 9 is viewed along its width, the axis X9 direction is inclined such that the inlet 91H is located closer to the outlet 92H. According to this configuration, it is possible to appropriately position the microbubble generator 9, which has a longer length along the axis X9 direction, closer to the flame ports 31F and 32F of the burners 31B and 32B. Moreover, since the microbubble generator 9 is inclined with the inlet 91H closer to the outlet 92H, drainage within the microbubble generator 9 can also be easily implemented. As a result, the water heater 1 achieves improved antifreeze performance.

[0216] Furthermore, in this water heater 1, the inlet 91H is located closer to the rear than the outlet 92H, and opens upwards in the vertical direction. With this configuration, the connection between the upstream side P2U of the hot water pipe P2 and the inlet portion 91 where the inlet 91H is formed is easily visible from the front of the water heater 1, and this connection can be easily reached through the housing opening 8H. As a result, the water heater 1 achieves further improvements in maintainability.

[0217] Furthermore, in this water heater 1, the outlet 92H is located closer to the front than the inlet 91H. From an assembly workability perspective, in most cases, the hot water supply interface 20H1 of the hot water supply connection component 20, which connects to the downstream end of the hot water pipe P2, opens towards the front surface of the housing 8, and this is also the case in this embodiment. Therefore, by utilizing the configuration where the outlet 92H is located closer to the front than the inlet 91H, the downstream side P2D of the hot water pipe P2 connected to the outlet 92H can be smoothly routed back to the hot water supply interface 20H1 of the hot water supply connection component 20. As a result, this water heater 1 achieves improved assembly workability and manufacturability, as well as reduced manufacturing costs.

[0218] Additionally, in this water heater 1, such as Figure 8As shown, the microbubble generator 9 has an inflow section 91, an outflow section 92, and a main body 90, each constructed using different components. Based on this configuration, various inflow sections 91 and outflow sections 92 of different shapes can be prepared in advance, and by using appropriately selected inflow sections 91 and outflow sections 92, various connection and installation methods, such as vertical or inclined installation, can be used to easily handle inflow and outflow in the vertical direction.

[0219] (Example 2)

[0220] like Figure 9 as well as Figure 10 As shown, in Embodiment 2, the water heater 2 uses a water supply pipe P201, a hot water pipe P202, and a microbubble generator 209 to replace the water supply pipe P1, hot water pipe P2, and microbubble generator 9 of the water heater 1 in Embodiment 1. The water supply pipe P201 is an example of the "specific pipe" of the present invention.

[0221] The other components of Example 2 are the same as those of Example 1. Therefore, the same reference numerals are assigned to the same components as in Example 1, and their descriptions are omitted or simplified.

[0222] like Figure 9 As shown, in Embodiment 2, the microbubble generator 209 is located inside the housing 8 and connected to the middle of the water supply pipe P201. The microbubble generator 209 is located on the first side, i.e. the right side, of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction.

[0223] Furthermore, the microbubble generator 209 is located to the right of the first combustion device 31 and the second combustion device 32 in the width direction.

[0224] The only difference between water supply pipe P201 and water supply pipe P1 in Example 1 is that the microbubble generator 209 is connected to the middle of water supply pipe P201. The other components of water supply pipe P201 are the same as those of water supply pipe P1 in Example 1.

[0225] The only difference between hot water pipe P202 and hot water pipe P2 in Example 1 is that hot water pipe P202 extends uninterruptedly from the upstream end to the downstream end. The other components of hot water pipe P202 are the same as those of hot water pipe P2 in Example 1.

[0226] like Figure 10 As shown, the microbubble generator 209 has a main body 290, an inflow section 291, and an outflow section 292, each composed of different devices.

[0227] Although the illustrations are omitted, the only difference between the main body 290 and the main body 90 of Embodiment 1 is that the orientation of the built-in Venturi tube component 93 and each stirring component 94 is opposite to that of Embodiment 1. That is, the Venturi tube component 93 is located on the inlet side 291, and each stirring component 94 is located on the outlet side 292. The other components of the main body 290 are the same as those of the main body 90 of Embodiment 1.

[0228] The inflow section 291 is the same as the outflow section 92 of Example 1. The inflow inlet 291H of the inflow section 291 is the same as the outflow outlet 92H of Example 1.

[0229] The outflow section 292 is the same as the inflow section 91 in Embodiment 1. The outflow outlet 292H of the outflow section 292 is the same as the inflow inlet 92H in Embodiment 1.

[0230] Similar to Embodiment 1, the main body 290 is centered on the axis X9. However, in Embodiment 2, one side in the direction of the axis X9 is moved to the front, and the other side in the direction of the axis X9 is moved to the rear.

[0231] The main body 290 is connected to the inflow portion 291 on one side in the X9 direction and to the outflow portion 292 on the other side in the X9 direction.

[0232] The microbubble generator 209 is formed as a generally cylindrical shape, with a length in the axial X9 direction greater than its outer width (outer diameter). The microbubble generator 209 is connected to the water supply pipe P201 midway, with its axial X9 direction inclined. When viewed along the width direction, the axial X9 direction is inclined such that the outlet 292H is located closer to the top than the inlet 291H. In this embodiment, the axial X9 direction extends approximately parallel to both the front-back and vertical directions.

[0233] The inlet 291H is located closer to the front than the outlet 292H. The outlet 292H is located closer to the rear than the inlet 291H and opens upwards in the vertical direction.

[0234] The inlet 291H is located on one side of the axis X9, that is, closer to the front than the main body 290, and is connected to the upstream side P201U of the water supply pipe P201. Water flows from the upstream side P201U of the water supply pipe P201 into the inlet 291H.

[0235] Outlet 292H is located on the other side of the axis X 209, that is, closer to the rear than the main body 290, and is connected to the downstream side P201D of the water supply pipe P201. Outlet 292H allows water containing microbubbles to flow out towards the downstream side P201D of the water supply pipe P201.

[0236] exist Figure 10 In the diagram, height H1 represents the height of the flame openings 31F and 32F of burners 31B and 32B. The microbubble generator 209 is located closer to or below the flame openings 31F and 32F of burners 31B and 32B.

[0237] exist Figure 10 In this context, height H4 represents the height of the upstream water supply path, from the water supply connection component 10 to the portion of the upstream side P201U of the water supply pipe P201 that connects to the inlet 291H. The inlet 291H is located at a height above the height H4 of the upstream water supply path.

[0238] exist Figure 10 In this context, height H3 represents the height of the internal flow path of the water flow control unit 50. The microbubble generator 209 is located closer to the top of the water flow control unit 50, and more specifically, it is located closer to the top of the internal flow path of the hot water injection control unit 60 at height H3.

[0239] The water heater 2 of Embodiment 2 with this configuration is the same as the water heater 1 of Embodiment 1. It can make hot water containing microbubbles flow out by means of hot water supply operation and hot water injection operation.

[0240] <Efficacy and Function>

[0241] In the water heater 2 of Embodiment 2, similarly to the water heater 1 of Embodiment 1, by configuring the microbubble generator 209 housed within the casing 8 to be positioned closer to and lower than the flame ports 31F and 32F of the burners 31B and 32B, the necessity for various countermeasures to suppress the influence of heat conducted from the first combustion device 31, the second combustion device 32, the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B to the microbubble generator 209 can be reduced. As a result, the water heater 2 can reduce the material and processing costs of the microbubble generator 209.

[0242] Therefore, the water heater 2 of Embodiment 2 can suppress the increase in manufacturing costs by housing the microbubble generator 209 within the housing 8.

[0243] Furthermore, in this water heater 2, the microbubble generator 209 is located on the first side, i.e., the right side, of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction. With this configuration, the microbubble generator 209 is positioned on the same side as the water supply pipe P201 in the width direction. Therefore, the water heater 2 can prevent the piping from becoming excessively long between the water supply pipe P201 and the microbubble generator 209, thus effectively utilizing the space within the housing 8.

[0244] Furthermore, in this water heater 2, the outlet 292H is located higher than the inlet 291H. Moreover, the inlet 291H is located at a height above the height H4 of the upstream water supply path from the water supply connection component 10 to the portion of the water supply pipe P201U upstream of the inlet 291H. According to this configuration, the vertical positional relationship is: outlet 292H > inlet 291H ≥ height H4 of the upstream water supply path. Therefore, when draining the microbubble generator 209, there is no need to install a separate drainage circuit; the water heater 2 can drain from the water supply connection component 10.

[0245] Furthermore, in this water heater 2, the microbubble generator 209 is located near the top of the water flow control unit 50, and more specifically, near the height H3 of the internal flow path of the hot water injection control unit 60. With this configuration, by removing the portion of the water supply pipe P201 located near the upstream side of the microbubble generator 209, i.e., the upstream side P201U of the water supply pipe P201, it is easy to access or remove the water flow control unit 50. As a result, the water heater 2 achieves improved maintainability.

[0246] Furthermore, in this water heater 2, when the microbubble generator 209 is viewed along its width, the axial X9 direction is inclined such that the outlet 292H is positioned closer to the inlet 291H. With this configuration, it is possible to appropriately position the microbubble generator 209, which has a longer length along the axial X9 direction, below the flame ports 31F and 32F of the burners 31B and 32B. Additionally, since the microbubble generator 209 is inclined with the outlet 292H positioned closer to the inlet 291H, drainage within the microbubble generator 209 can be easily implemented. As a result, the water heater 2 achieves improved antifreeze performance.

[0247] Furthermore, in this water heater 2, the outlet 292H is located further rearward than the inlet 291H and opens upward in the vertical direction. With this configuration, the connection between the downstream side P201D of the water supply pipe P201 and the outlet 292 where the outlet 292H is formed can be easily observed from the front of the water heater 2, and this connection can be easily reached through the housing opening 8H. As a result, the water heater 2 achieves further improvements in maintainability.

[0248] Furthermore, in this water heater 2, the inlet 291H is located closer to the front of the outlet 292H. From an assembly workability perspective, in most cases, the water supply connection port 50H1 of the water flow control unit 50, which connects to the upstream end of the water supply pipe P201, opens towards the front surface of the housing 8, and this is also the case in this embodiment. Therefore, by configuring the inlet 291H to be located closer to the front of the outlet 292H, the upstream side P201U of the water supply pipe P201 connected to the inlet 291H can be smoothly routed back to the water supply connection port 50H1 of the water flow control unit 50. As a result, this water heater 2 achieves improved assembly workability and manufacturability, as well as reduced manufacturing costs.

[0249] Although the present invention has been described above with reference to Embodiments 1 and 2, the present invention is not limited to Embodiments 1 and 2. Undoubtedly, it can be appropriately modified and applied without departing from its spirit.

[0250] The present invention also includes a single-function water heater, that is, a configuration that is formed by removing the second combustion device 32 for the bathtub, the second main heat exchanger 42A, the second auxiliary heat exchanger 42B, the hot water injection control unit 60, the bathtub return pipe P3, the intermediate pipe P31, the bathtub inlet pipe P4, the water pump 69, etc. from Embodiments 1 and 2.

[0251] In embodiments 1 and 2, although the microbubble generators 9 and 209 are located on the first side (i.e., the right side) of the first main heat exchanger 41A, the first auxiliary heat exchanger 41B, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B in the width direction, the present invention is not limited to this configuration. For example, the microbubble generator can be located as long as it is located closer to the bottom than the flame opening of the burner, or it can be located on the other side (i.e., the second side), in front, behind, or below the heat exchanger.

[0252] In Examples 1 and 2, although the fuel for the first combustion device 31 and the second combustion device 32 is fuel gas such as city gas or liquefied petroleum gas, the present invention is not limited to this configuration. For example, the fuel for the combustion device may also be a liquid such as kerosene.

[0253] In Embodiment 1, although the inlet 91H is located further rearward than the outlet 92H and opens upward in the vertical direction, the present invention is not limited to this configuration. For example, regarding the orientation of the microbubble generator 9 in the water heater 1 of Embodiment 1, the present invention also includes a configuration in which the outlet 92H is located further rearward than the inlet 91H and opens downward in the vertical direction. With this configuration, the connection between the downstream side P2D of the hot water pipe P2 and the outlet 92H can be easily observed from the front, and the connection can be easily accessed through the housing opening 8H, thus further improving maintainability.

[0254] In Embodiment 2, although the outlet 292H is located further rearward than the inlet 291H and opens upward in the vertical direction, the present invention is not limited to this configuration. For example, regarding the orientation of the microbubble generator 209 of the water heater 2 in Embodiment 2, the present invention also includes a configuration in which the inlet 291H is located further rearward than the outlet 292H and opens downward in the vertical direction. With this configuration, the connection between the upstream side P201U of the water supply pipe P201 and the inlet 291H can be easily observed from the front, and the connection can be easily accessed through the housing opening 8H, thus further improving maintainability.

[0255] In embodiments 1 and 2, although the water flow control unit 50 has a bypass servo mechanism 51 and a water flow servo mechanism 52, the present invention is not limited to this configuration. As long as the water flow control unit can control the flow rate of water flowing in the water supply pipe, it can be any configuration. For example, the present invention also includes a configuration in which the water flow control unit has only one of the bypass servo mechanism and the water flow servo mechanism.

[0256] In embodiments 1 and 2, although the microbubble generators 9 and 209 are formed into a generally cylindrical shape with a length in the axial direction X9 greater than the outer diameter, the present invention is not limited to this configuration. For example, as long as the length in the axial direction of the microbubble generator is greater than the outer width, it can also be formed into a generally cylindrical shape such as a quadrilateral cylinder or a polygonal cylinder.

[0257] In embodiments 1 and 2, although the axis X9 direction extends substantially parallel to the front-back and up-down directions, the present invention is not limited to this configuration. For example, the axis direction may also be inclined relative to the front-back and up-down directions.

[0258] (Industry availability)

[0259] This invention can be applied, for example, to: a water heater that only has a hot water supply function, a water heater that has a hot water supply function and a bathtub hot water reheating function, and a hot water supply and heating device that has a hot water supply function and a function of circulating hot water between the device and the heating device.

Claims

1. A water heater, comprising: The shell comprises a main body and a front panel, wherein... The aforementioned housing body has a housing opening with an open front surface and a box shape that is recessed towards the rear, with the aforementioned front plate covering the aforementioned housing opening; A combustion device, which is housed within the aforementioned housing, generates high-temperature gas and has a combustion chamber and a burner with the flame outlet located within the aforementioned combustion chamber; A heat exchanger, housed within the aforementioned casing at a position closer to the top than the aforementioned combustion chamber, uses the aforementioned high-temperature gas to heat water passing through it, thereby converting it into hot water. The water supply pipe is housed in the aforementioned housing and is located on one side of the aforementioned heat exchanger, i.e., the first side, in the width direction orthogonal to the front-back direction and the vertical direction, and extends along the aforementioned vertical direction to connect to the aforementioned heat exchanger. A hot water pipe is housed within the aforementioned housing, located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction, and extends along the aforementioned vertical direction to be connected to the aforementioned heat exchanger. A water supply connection component, located on the lower surface of the main body of the housing, is used to connect the water supply pipe to the water supply path located outside the housing. A hot water supply connection component, located on the lower surface of the housing body, is used to connect the hot water pipe to a hot water supply path located outside the housing. as well as A water flow control unit, disposed between the aforementioned water supply connection component and the aforementioned water supply pipe, is used to control the flow rate of water flowing through the aforementioned water supply pipe; characterized in that, The water heater also includes a microbubble generator, which is connected midway to the hot water pipe within the housing and is formed as a cylinder with a length greater than its outer width in the axial direction. Microbubbles are generated solely by the flow of hot water within the cylinder. The above-mentioned microbubble generator has the following characteristics: An inlet, located on one side in the aforementioned axial direction, allows the hot water to flow in from the upstream side of the aforementioned hot water pipe; and The outlet, located on the other side of the aforementioned axial direction, allows the hot water containing the aforementioned microbubbles to flow downstream of the aforementioned hot water pipe. The inlet and outlet of the aforementioned microbubble generator are located closer to the bottom than the flame port. The aforementioned microbubble generator is located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction. A portion of the aforementioned water supply pipe is located closer to the bottom than the aforementioned flame opening, and is situated above the aforementioned microbubble generator.

2. The water heater according to claim 1, characterized in that, The aforementioned water control unit has a water supply connection port that opens toward the aforementioned front surface side of the aforementioned housing. The water supply pipe extends forward from the upstream end connected to the water supply port, then bends upward, then bends backward and extends to a position closer to the bottom than the flame port and above the microbubble generator, then bends upward and extends to a position closer to the top than the flame port.

3. The water heater according to claim 1 or 2, characterized in that, The inlet and outlet of the microbubble generator are located closer to the top than the water volume control unit.

4. The water heater according to claim 1 or 2, characterized in that, One of the aforementioned inlet and outlet is located at a position closer to the rear than the other of the aforementioned inlet and outlet.

5. The water heater according to claim 4, characterized in that, The aforementioned inlet and outlet are both open in the vertical direction.

6. The water heater according to claim 1 or 2, characterized in that, The aforementioned axial direction is inclined relative to the vertical direction.

7. The water heater according to claim 6, characterized in that, At least one of the upstream side of the hot water pipe and the microbubble generator, and the microbubble generator and the downstream side of the hot water pipe, forms an obtuse angle.

8. The water heater according to claim 1 or 2, characterized in that, The aforementioned inlet is located above the aforementioned outlet. The outlet is located at the top of the downstream hot water supply flow path in the height direction from the portion of the hot water pipe connected to the outlet to the hot water supply connection component.

9. A water heater, comprising: The shell comprises a main body and a front panel, wherein... The aforementioned housing body has a housing opening with an open front surface and a box shape that is recessed towards the rear, with the aforementioned front plate covering the aforementioned housing opening; A combustion device, which is housed within the aforementioned housing, generates high-temperature gas and has a combustion chamber and a burner with the flame outlet located within the aforementioned combustion chamber; A heat exchanger, housed within the aforementioned casing at a position closer to the top than the aforementioned combustion chamber, uses the aforementioned high-temperature gas to heat water passing through it, thereby converting it into hot water. The water supply pipe is housed in the aforementioned housing and is located on one side of the aforementioned heat exchanger, i.e., the first side, in the width direction orthogonal to the front-back direction and the vertical direction, and extends along the aforementioned vertical direction to connect to the aforementioned heat exchanger. A hot water pipe is housed within the aforementioned housing, located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction, and extends along the aforementioned vertical direction to be connected to the aforementioned heat exchanger. A water supply connection component, located on the lower surface of the main body of the housing, is used to connect the water supply pipe to the water supply path located outside the housing. A hot water supply connection component, located on the lower surface of the housing body, is used to connect the hot water pipe to a hot water supply path located outside the housing. as well as A water flow control unit, disposed between the aforementioned water supply connection component and the aforementioned water supply pipe, is used to control the flow rate of water flowing through the aforementioned water supply pipe; characterized in that, The water heater also includes a microbubble generator, which is connected midway to the water supply pipe within the housing and is formed as a cylinder with a length greater than its outer width in the axial direction. Microbubbles are generated solely by the flow of hot water within the cylinder. The above-mentioned microbubble generator has the following characteristics: An inlet, located on one side in the aforementioned axial direction, allows the aforementioned hot water to flow in from the upstream side of the aforementioned water supply pipe; and The outlet, located on the other side of the aforementioned axial direction, allows the hot water containing the aforementioned microbubbles to flow downstream of the aforementioned water supply pipe. The inlet and outlet of the aforementioned microbubble generator are located closer to the bottom than the flame port. The aforementioned microbubble generator is located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction. The aforementioned axial direction is inclined relative to the vertical direction. A portion of the aforementioned water supply pipe is located closer to the bottom than the aforementioned flame opening, and is situated above the aforementioned microbubble generator.

10. The water heater according to claim 9, characterized in that, The aforementioned outlet is located further back than the aforementioned inlet. The aforementioned water control unit has a water supply connection port that opens toward the aforementioned front surface side of the aforementioned housing. The upstream side of the aforementioned water supply pipe extends forward from the upstream end connected to the aforementioned water supply connection port, then bends upward, and then bends backward to connect with the aforementioned inlet. The aforementioned portion of the downstream side of the aforementioned water supply pipe is located closer to the bottom than the aforementioned flame opening, and is located above the aforementioned microbubble generator.

11. The water heater according to claim 9 or 10, characterized in that, The aforementioned portion of the downstream side of the aforementioned water supply pipe has a horizontally extending portion.

12. The water heater according to claim 9 or 10, characterized in that, The aforementioned outlet is located above the aforementioned inlet. The aforementioned inlet is located at the uppermost point in the height direction of the upstream water supply flow path, from the aforementioned water supply connection component to the portion of the aforementioned water supply pipe connected to the aforementioned inlet.

13. The water heater according to any one of claims 1, 2, 9 and 10, characterized in that, The aforementioned microbubble generator is made of a resin that is heat-resistant to hot water.

14. The water heater according to any one of claims 1, 2, 9 and 10, characterized in that, The aforementioned microbubbles originate from air that has dissolved in the aforementioned hot water.

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