water heater

Abstract

To provide a water heater that can suppress rising manufacturing costs in a configuration in which a microbubble generator is housed within the casing. [Solution] The water heater 1 comprises a housing 8, combustion devices 31, 32, heat exchangers 41A~42B, water supply pipe P1, hot water supply pipe P2, water supply connection member 10, hot water supply connection member 20, and water volume control unit 50. The water heater 1 further comprises a microbubble generator 9 connected to a specific pipe P2, which is one of the water supply pipes P1 and hot water supply pipe P2, within the housing 8. The microbubble generator 9 is roughly cylindrical in shape, with a length in the axial direction X9 greater than its outer width, and generates fine bubbles in the hot water flowing inside. The microbubble generator 9 is located on one side in the axial direction X9 and has an inlet 91H into which hot water flows from the upstream side P2U of the specific pipe P2, and an outlet 92H located on the other side in the axial direction X9 that discharges the hot water containing the microbubbles to the downstream side P2D of the specific pipe P2. The microbubble generator 9 is located below the flame ports 31F, 32F of the burners 31B, 32B.

Description

Technical Field

[0001] The present invention relates to a water heater.

Background Art

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

[0003] The housing has a housing main body. The housing main body has a housing opening that opens the front surface and is a substantially box-shaped recessed toward the rear. Although not shown in Patent Document 1, the housing has a front plate that covers the housing opening. The combustion device is housed in the housing. The combustion device has a combustion chamber and a burner whose flame port is located in the combustion chamber, and generates high-temperature gas. The heat exchanger is housed above the combustion chamber in the housing. The heat exchanger heats the water passing through the inside with high-temperature gas and converts it into hot water.

[0004] As shown in FIG. 1 etc. of Patent Document 1, the water heater includes a water supply pipe, a hot water supply pipe, a water supply connection member, and a hot water supply connection member.

[0005] The water supply pipe and the hot water supply pipe are housed in the housing and are respectively connected to the heat exchanger. The water supply connection member and the hot water supply connection member are located on the lower surface of the housing main body. The water supply connection member is for connecting the water supply pipe and a water supply path outside the housing. The hot water supply connection member is for connecting the hot water supply pipe and a hot water supply path outside the housing. Note that a water volume control unit for controlling the flow rate of the water flowing through the water supply pipe is provided between the water supply connection member and the water supply pipe.

[0006] Patent Document 2 discloses an example of a conventional microbubble generator. This microbubble generator is placed, for example, in a shower system or in the middle of the piping to a faucet. This microbubble generator has a roughly cylindrical shape in which the axial length is greater than the outer width. This microbubble generator generates microbubbles in the hot water flowing inside. The larger the axial length of this microbubble generator is compared to the outer diameter, the easier it is to make the microbubbles generated in the hot water finer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-55929 [Patent Document 2] Japanese Patent Publication No. 2020-171914 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Incidentally, it has been considered to house the conventional microbubble generator within the casing of the conventional water heater described above. However, in this case, the microbubble generator is long in the axial direction and tends to be bulky, and is easily affected by the combustion device and heat exchanger within the casing, which is constrained in size and shape due to the installation location. For this reason, water heaters that house the microbubble generator within the casing tend to require various measures to suppress the influence of the combustion device and heat exchanger, which may result in increased manufacturing costs.

[0009] This invention has been made in view of the above-mentioned conventional circumstances, and aims to solve the problem of providing a water heater that can suppress the rise in manufacturing costs in a configuration in which a microbubble generator is housed inside the casing. [Means for solving the problem]

[0010] The water heater of the present invention comprises a housing having a housing opening that opens to the front and a roughly box-shaped housing body that is recessed toward the rear, and a front plate that covers the housing opening, A combustion device comprising a combustion chamber and a burner whose flame port is located within the combustion chamber, which generates high-temperature gas, is housed within the aforementioned enclosure. A heat exchanger is housed above the combustion chamber within the aforementioned housing and heats the water passing through it with the high-temperature gas to convert it into hot water. A water supply pipe is housed within the aforementioned housing, located on the first side which is one side of the heat exchanger in the width direction perpendicular to the front-rear and up-down directions, extending in the up-down direction and connected to the heat exchanger, A hot water supply pipe is housed within the aforementioned housing, located to the first side of the heat exchanger in the width direction, extending in the vertical direction, and connected to the heat exchanger. A water supply connecting member located on the lower surface of the housing body, for connecting the water supply pipe and the water supply channel located outside the housing, A hot water supply connecting member located on the lower surface of the housing body for connecting the hot water supply pipe and the hot water supply passage located outside the housing, A water flow control unit is provided between the water supply connection member and the water supply pipe, which controls the flow rate of water flowing through the water supply pipe. In a water heater, The housing further comprises a microbubble generator connected to a specific pipe, which is either the water supply pipe or the hot water supply pipe, having a roughly cylindrical shape with an axial length greater than its outer width, and generating microbubbles in the hot water flowing inside. The microbubble generator is located on one side in the axial direction and has an inlet into which the hot water flows in from the upstream side of the specific pipe, It has an outlet located on the other side in the axial direction, which discharges the hot water containing the fine bubbles to the downstream side of the specific pipe, The microbubble generator is characterized by being located below the flame port.

[0011] In the water heater of the present invention, the microbubble generator housed within the casing is positioned below the flame port of the burner, thereby reducing the need for various measures to suppress the influence of heat transferred from the combustion device and heat exchanger to the microbubble generator, such as constructing the microbubble generator from a highly heat-resistant resin or metal. As a result, this water heater can reduce material and processing costs for the microbubble generator.

[0012] Therefore, the water heater of the present invention can suppress the increase in manufacturing costs in a configuration in which a microbubble generator is housed within the casing.

[0013] The microbubble generator is preferably located on the first side of the heat exchanger in the width direction.

[0014] In this configuration, the microbubble generator is positioned on the same side as the designated pipe in the width direction. Therefore, this water heater can prevent the piping between the designated pipe and the microbubble generator from becoming excessively long, allowing for efficient use of space within the housing.

[0015] The designated pipe should preferably be a hot water supply pipe. The inlet should preferably be located above the outlet. Furthermore, the outlet should preferably be located at a height greater than or equal to the downstream hot water supply flow path from the point where the hot water supply pipe connects to the outlet to the hot water supply connection member.

[0016] In this configuration, the vertical positional relationship is inlet > outlet ≥ downstream hot water supply channel. Therefore, when draining water from the microbubble generator, this water heater can drain water from the hot water supply connection component without requiring a separate draining circuit.

[0017] In the above case, it is desirable that the microbubble generator be located above the water volume control unit.

[0018] According to this configuration, by removing the portion located downstream of the fine bubble generator in the hot water supply pipe, it becomes possible to easily touch the water volume control unit or remove the water volume control unit. As a result, this hot water supply device can achieve an improvement in maintainability.

[0019] The specific pipe is preferably the hot water supply pipe. And when viewing the fine bubble generator along the width direction, it is desirable that the axial direction is inclined such that the inlet is located above the outlet.

[0020] According to this configuration, it is appropriately possible to arrange a long and slender fine bubble generator having a long axial direction below the flame port of the burner. Further, since the fine bubble generator is inclined such that the inlet is located above the outlet, draining of water in the fine bubble generator can also be easily performed. As a result, this hot water supply device can achieve an improvement in anti-freezing performance.

[0021] In the above case, it is desirable that one of the inlet and the outlet is located behind the other of the inlet and the outlet and opens in the vertical direction.

[0022] According to this configuration, when the inlet is located behind the outlet, the inlet opens upward in the vertical direction. For this reason, in this hot water supply device, it becomes easier to visually recognize the connection portion between the upstream side of the hot water supply pipe and the inlet from the front, and it also becomes easier to reach out and touch the connection portion from the housing opening. Further, when the outlet is located behind the inlet, the outlet opens downward in the vertical direction. For this reason, in this hot water supply device, it becomes easier to visually recognize the connection portion between the downstream side of the hot water supply pipe and the outlet from the front, and it also becomes easier to reach out and touch the connection portion from the housing opening. As a result, this hot water supply device can further achieve an improvement in maintainability.

[0023] Also, in the above case, it is desirable that the outlet is located in front of the inlet.

[0024] The hot water connection port of the hot water supply connection component, to which the hot water supply pipe connects, is often opened towards the front of the housing for ease of assembly. Therefore, with the outlet located in front of the inlet, the downstream side of the hot water supply pipe connected to the outlet can be routed smoothly to the hot water connection port of the hot water supply connection component. As a result, this water heater can achieve improved assembly workability and processability, as well as reduced manufacturing costs.

[0025] The designated pipe should preferably be a water supply pipe. The outlet should preferably be located above the inlet. Furthermore, the inlet should preferably be located at a height greater than or equal to the upstream water supply channel from the water supply connection member to the portion of the water supply pipe that connects to the inlet.

[0026] In this configuration, the vertical positional relationship is outlet > inlet ≥ upstream water supply channel. Therefore, when draining water from the microbubble generator, this water heater can drain water from the water supply connection component without requiring a separate draining circuit.

[0027] In the above case, it is desirable that the microbubble generator be located above the water volume control unit.

[0028] This configuration allows for easy access to and removal of the water flow control unit by removing the portion of the water supply pipe located upstream of the microbubble generator. As a result, this water heater achieves improved maintainability.

[0029] The designated pipe should preferably be a water supply pipe. Furthermore, when viewing the microbubble generator along its width, it is desirable that the axial direction be inclined such that the outlet is located above the inlet.

[0030] This configuration allows for the proper placement of a long, axially-oriented microbubble generator below the burner's flame port. Furthermore, because the microbubble generator is inclined so that its outlet is above its inlet, draining water from within the generator is easily accomplished. As a result, this water heater achieves improved freeze resistance.

[0031] In the above case, it is desirable that one of the inlet and outlet is located behind the other and opens vertically.

[0032] With this configuration, if the inlet is located behind the outlet, the inlet opens vertically downwards. Therefore, the connection between the upstream side of the water supply pipe and the inlet is easily visible from the front, and it is also easy to reach and touch the connection through the housing opening. Similarly, if the outlet is located behind the inlet, the outlet opens vertically upwards. Therefore, the connection between the downstream side of the water supply pipe and the outlet is easily visible from the front, and it is also easy to reach and touch the connection through the housing opening. As a result, this water heater achieves even greater maintainability.

[0033] Furthermore, in the above case, it is desirable that the inlet be located forward of the outlet.

[0034] The water supply connection port in the water volume control unit, to which the water supply pipe connects, is often positioned facing the front of the housing for ease of assembly. Therefore, a configuration where the inlet is located in front of the outlet allows for smooth routing of the upstream side of the water supply pipe connected to the inlet, leading to the water supply connection port in the water volume control unit. As a result, this water heater achieves improved assembly and machinability, as well as reduced manufacturing costs.

[0035] A microbubble generator preferably has an inlet section formed therein and connected to the upstream side of a specific pipe, an outlet section formed therein and connected to the downstream side of the specific pipe, and a main body section connected to the inlet section on one side in the axial direction and to the outlet section on the other side in the axial direction, which generates microbubbles in the hot water flowing inside. Furthermore, it is preferable that the inlet section, outlet section, and main body section are each composed of separate parts.

[0036] With this configuration, multiple types of inlet and outlet sections with different shapes are prepared in advance, and by using the appropriate inlet and outlet section from among them, it is possible to easily accommodate various connection and mounting configurations, such as vertical mounting or inlet and outlet in a vertical direction with diagonal mounting. [Effects of the Invention]

[0037] According to the water heater of the present invention, it is possible to suppress the increase in manufacturing costs in a configuration in which a microbubble generator is housed inside the casing. [Brief explanation of the drawing]

[0038] [Figure 1] Figure 1 is a perspective view of the water heater in Example 1. [Figure 2] Figure 2 is a perspective view of the water heater of Example 1, with the front panel removed. [Figure 3] Figure 3 is a schematic diagram of the water heater in Example 1. [Figure 4] Figure 4 is a partial perspective view of the water heater of Example 1, showing the combustion chamber, burner flame port, microbubble generator, etc. [Figure 5] Figure 5 is a perspective view of the water heater of Embodiment 1, showing the state after removing the housing body, combustion fan, first combustion device, second combustion device, first main heat exchanger, first auxiliary heat exchanger, second main heat exchanger, second auxiliary heat exchanger, etc., from Figure 2. [Figure 6] Figure 6 is an exploded perspective view relating to the water heater of Example 1, showing the hot water pipe, microbubble generator, hot water connection member, hot water filling control unit, cold water connection member, water volume control unit, bypass pipe, etc. [Figure 7]Figure 7 is a side view of the water heater of Example 1, showing the hot water pipe, bypass pipe, microbubble generator, water supply connection member, water volume control member, hot water filling control member, etc. [Figure 8] Figure 8 is an exploded perspective view of the microbubble generator for the water heater of Example 1. [Figure 9] Figure 9 is a schematic diagram of the water heater in Example 2. [Figure 10] Figure 10 is a side view of the water heater of Example 2, showing the water supply pipe, microbubble generator, water supply connection member, hot water supply connection member, water volume control unit, hot water filling control unit, etc. [Modes for carrying out the invention]

[0039] Examples 1 and 2, which embody the present invention, will be described below with reference to the drawings.

[0040] (Example 1) As shown in Figure 1, 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 plate 8B side of the housing 8 of the water heater 1, that is, the front side of the paper in Figure 1, is defined as the front of the water heater 1, the left side of the paper in Figure 1 is defined as the left side of the water heater 1, and the top side of the paper in Figure 1 is defined as the top of the water heater 1. Furthermore, the front, back, left, right, and up and down directions shown in Figures 2 and onward all correspond to those in Figure 1. The components of the water heater 1 will now be described.

[0041] <Enclosure> As shown in Figure 1, the water heater 1 is equipped with a housing 8. The housing 8 has a housing body 8A and a front panel 8B.

[0042] As shown in Figure 2, the main enclosure 8A has an enclosure opening 8H that opens to the front and is roughly box-shaped, concave towards the rear. As shown in Figure 1, the front plate 8B is roughly rectangular and flat, covering the enclosure opening 8H. The main enclosure 8A and the front plate 8B divide the internal space into roughly rectangular parallelepiped shapes.

[0043] The width direction of the housing 8 is perpendicular to the front-to-back and up-to-down directions, and in this embodiment, it coincides with the left-to-right direction. The water heater 1 is often installed in the pipe shaft of an apartment building. Therefore, the size and shape of the housing 8 in the up-to-down, front-to-back, and width directions are constrained so that it fits into such a pipe shaft.

[0044] An exhaust opening 8B1 is provided at the upper end of the front panel 8B, exposing the exhaust port 49, which will be described later. An outside air intake opening 8B2 is provided at the lower end of the front panel 8B, for introducing outside air into the housing 8.

[0045] <Combustion fan, first combustion device, and second combustion device> As shown in Figures 2 and 3, the water heater 1 is equipped with 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.

[0046] The combustion fan 30F is housed in the lower part of the enclosure 8. The combustion fan 30F supplies combustion air to the first combustion device 31 and the second combustion device 32.

[0047] The first combustion device 31 and the second combustion device 32 are housed in the middle section of the housing 8 in the vertical direction. As shown in Figures 3 and 4, 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.

[0048] The first combustion device 31 has a combustion chamber 31C and a burner 31B. The second combustion device 32 has a combustion chamber 32C and a burner 32B. The combustion chamber 31C and burner 31B and the combustion chamber 32C and burner 32B are separated by a partition plate 33A as shown in Figure 3.

[0049] In Figure 4, the partition plate 33A is not shown. In the first combustion device 31, the flame ports 31F of the burner 31B are located inside the combustion chamber 31C and are arranged in a row in the front-to-back and left-to-right directions. In the second combustion device 32, the flame ports 32F of the burner 32B are located inside the combustion chamber 32C and are arranged in a row in the front-to-back and left-to-right directions.

[0050] The height of the flame port 31F of burner 31B and the height of the flame port 32F of burner 32B are the same. In Figure 7, the heights of the flame ports 31F and 32F of burners 31B and 32B are shown as height H1.

[0051] As shown in Figure 3, in the first combustion device 31, fuel gas such as city gas or propane gas is supplied to the burner 31B from a gas supply source (not shown) located outside the housing 8 via a gas supply pipe 30G, a main gas solenoid valve 30V, a gas proportional valve 30P, a branch pipe 31P, and a first gas solenoid valve 31V. The burner 31B discharges the fuel gas from the flame port 31F and burns it. As a result, the first combustion device 31 generates high-temperature gas, which is the combustion exhaust gas.

[0052] In the second combustion device 32, fuel gas is supplied to the burner 32B from a gas supply source (not shown) located outside the housing 8 via a gas supply pipe 30G, a main gas solenoid valve 30V, a gas proportional valve 30P, a branch pipe 32P, and a second gas solenoid valve 32V. The burner 32B discharges the fuel gas from the flame port 32F and burns it. As a result, the second combustion device 32 generates high-temperature gas, which is the combustion exhaust gas.

[0053] <First main heat exchanger, first secondary heat exchanger, second main heat exchanger, and second secondary heat exchanger> As shown in Figures 2 and 3, the water heater 1 is equipped with 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.

[0054] The first main heat exchanger 41A, the first secondary heat exchanger 41B, the second main heat exchanger 42A, and the second secondary heat exchanger 42B are examples of the "heat exchanger" of the present invention.

[0055] As shown in Figure 3, the second combustion device 32, the second main heat exchanger 42A, and the second auxiliary heat exchanger 42B are for reheating the bathtub 4 installed in the bathroom. In other words, the water heater 1 is a bath water heater.

[0056] The first main heat exchanger 41A, the first secondary heat exchanger 41B, the second main heat exchanger 42A, and the second secondary heat exchanger 42B are housed in the upper part of the housing 8.

[0057] 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.

[0058] The first main heat exchanger 41A and the second main heat exchanger 42A share the same outer casing 40B shown in Figure 2 and are separated by a partition plate 33B shown in Figure 3.

[0059] The first auxiliary heat exchanger 41B is located above the first main heat exchanger 41A. The second auxiliary heat exchanger 42B is located above the second main heat exchanger 42A.

[0060] The first auxiliary heat exchanger 41B and the second auxiliary heat exchanger 42B share the same boiler body 40C shown in Figure 2 and are separated by a partition plate 33C shown in Figure 3.

[0061] As shown in Figure 2, the can body 40C has an exhaust port 49. The exhaust port 49 protrudes forward from the front of the can body 40C. As shown in Figure 1, the exhaust port 49 passes through the exhaust opening 8B1 of the front plate 8B and is exposed to the outside of the housing 8.

[0062] 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 boiler body 40C and is discharged to the outside of the housing 8 through the exhaust port 49.

[0063] As shown in Figure 3, the first main heat exchanger 41A has heat transfer tubes 41A1. In Figure 3, the heat transfer tubes 41A1 are shown in a simplified manner, but the heat transfer tubes 41A1 meander, including multiple straight sections and multiple folded sections that are folded in an arc shape to connect the straight sections. Each straight section of the heat transfer tubes 41A1 has multiple heat transfer fins.

[0064] The first main heat exchanger 41A exchanges heat between the water flowing through the heat transfer tubes 41A1 and the high-temperature gas generated by the first combustion device 31, and absorbs the sensible heat of the high-temperature gas.

[0065] The first auxiliary heat exchanger 41B has heat transfer tubes 41B1. In Figure 3, the heat transfer tubes 41B1 are shown in a simplified manner, but the heat transfer tubes 41B1 are corrugated tubes that meander, including multiple straight sections and multiple folded sections that are folded in an arc shape to connect the straight sections.

[0066] The first auxiliary heat exchanger 41B exchanges heat between the water flowing through the heat transfer tubes 41B1 and the high-temperature gas generated by the first combustion device 31, and absorbs the latent heat of the high-temperature gas.

[0067] The second main heat exchanger 42A has heat transfer tubes 42A1, which have the same configuration as heat transfer tubes 41A1. The second main heat exchanger 42A exchanges heat between water flowing through the heat transfer tubes 42A1 and the high-temperature gas generated by the second combustion device 32, and absorbs the sensible heat of the high-temperature gas.

[0068] The second auxiliary heat exchanger 42B has a heat transfer tube 42B1 which has the same configuration as the heat transfer tube 41B1. The second auxiliary heat exchanger 42B exchanges heat between the water flowing through the heat transfer tube 42B1 and the high-temperature gas generated by the second combustion device 32, and absorbs the latent heat of the high-temperature gas.

[0069] In this way, 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 each heat the water passing through them with high-temperature gas to convert it into hot water.

[0070] As shown in Figures 2 and 3, the upper end of the drain pipe 48P is connected to the bottom wall of the boiler body 40C. The lower end of the drain pipe 48P is connected to the neutralizer 48. The condensate generated inside the boiler body 40C is guided to the neutralizer 48 by the drain pipe 48P. The neutralizer 48 neutralizes the condensate with a neutralizing agent and then discharges it to the outside of the housing 8.

[0071] <Water supply pipes, intermediate water supply pipes, hot water pipes, and bypass pipes> As shown in Figures 2 to 5, the water heater 1 is equipped with a water supply pipe P1, an intermediate water supply pipe P11, a hot water supply pipe P2, and a bypass pipe P21. The hot water supply pipe P2 is an example of the "specific pipe" of the present invention.

[0072] The water supply pipe P1, intermediate water supply pipe P11, hot water supply pipe P2, and bypass pipe P21 are housed within the enclosure 8. In the width direction, the water supply pipe P1, intermediate water supply pipe P11, hot water supply pipe P2, and bypass pipe P21 are located on the first side, i.e., the right side, which is one 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.

[0073] Furthermore, the water supply pipe P1, intermediate water supply pipe P11, hot water supply pipe P2, and bypass pipe P21 are located to the right of the first combustion device 31 and the second combustion device 32 in the width direction.

[0074] As shown in Figures 3 and 5, the upstream end of the water supply pipe P1 is connected to the water supply connection port 50H1 of the water volume control unit 50, which will be described later. The downstream end of the water supply pipe P1 is located above the upstream end. 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 vertically, bending multiple times between its upstream and downstream ends.

[0075] The upstream end of the intermediate feedpipe 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 feedpipe P11 is located below the upstream end of the intermediate feedpipe P11. The downstream end of the intermediate feedpipe P11 is connected to the inlet of the heat transfer tube 41A1 of the first main heat exchanger 41A.

[0076] The middle section of water supply pipe P1 and the middle section of intermediate water supply pipe P11 are connected via a thin connecting pipe P12.

[0077] The upstream end of the hot water supply pipe P2 is connected to the outlet of the heat transfer tube 41A1 of the first main heat exchanger 41A. The downstream end of the hot water supply pipe P2 is located below the upstream end. The downstream end of the hot water supply pipe P2 is connected to the hot water connection port 20H1 of the hot water connection member 20, which will be described later. The hot water supply pipe P2 extends vertically, bending multiple times between its upstream and downstream ends. A microbubble generator 9, which will be described later, is connected to the middle of the hot water supply pipe P2.

[0078] The upstream end of bypass pipe P21 is connected to the bypass connection port 50H2 of the water volume control unit 50, which will be described later. The downstream end of bypass pipe P21 is located above the upstream end of bypass pipe P21. The downstream end of bypass pipe P21 is connected near the upstream end of the hot water supply pipe P2.

[0079] <Water supply connection member, hot water connection member, water volume control unit, and hot water filling control unit> As shown in Figures 2, 3, and 5, the water heater 1 includes a water supply connection member 10, a hot water supply connection member 20, a water volume control unit 50, and a hot water filling control unit 60.

[0080] The water supply connection member 10 is located on the right side of the lower surface of the housing body 8A. As shown in Figure 3, the portion of the water supply connection member 10 that protrudes below the lower surface of the housing body 8A has a connection part that connects the water supply pipe P1 to the water supply channel 10S located outside the housing 8, and a water filter that also serves as a drain plug.

[0081] The portion of the water supply connection member 10 that protrudes above the lower surface of the housing body 8A is connected to the water volume control unit 50.

[0082] As shown in Figure 5, the water volume control unit 50 has a water supply connection port 50H1 to which the upstream end of the water supply pipe P1 is connected. In other words, the water volume control unit 50 is installed between the water supply connection member 10 and the water supply pipe P1. The water volume control unit 50 also has a bypass connection port 50H2 to which the upstream end of the bypass pipe P21 is connected.

[0083] As shown in Figure 3, the water volume control unit 50 has a bypass servo 51 and a water volume servo 52.

[0084] The bypass servo 51 switches between a bypass closed state, which directs the water supplied to the water volume control unit 50 only to the water supply pipe P1, and a bypass open state, which directs the water supplied to the water volume control unit 50 not only to the water supply pipe P1 but also to the bypass pipe P21.

[0085] The water flow servo 52 controls the flow rate of water flowing through the water supply pipe P1 when the bypass servo 51 is in the bypass closed state. On the other hand, when the bypass servo 51 is in the bypass open state, the water flow servo 52 controls the flow rate of water flowing through the water supply pipe P1 and the bypass pipe P21.

[0086] As shown in Figures 2, 3, and 5, the hot water connection member 20 is located on the right side of the lower surface of the housing body 8A, to the right and rearward of the cold water connection member 10. As shown in Figure 3, the portion of the hot water connection member 20 that protrudes below the lower surface of the housing body 8A has a connection part for connecting the hot water pipe P2 to the hot water passage 20S located outside the housing 8, a water hammer buffer valve, and a pressurized safety valve / drain plug.

[0087] As shown in Figure 5, the portion of the hot water connection member 20 that protrudes above the lower surface of the housing body 8A is branched in a T-shape. The hot water connection member 20 has a hot water connection port 20H1 at the front end of the portion that protrudes forward from the branch, to which the downstream end of the hot water pipe P2 is connected.

[0088] The portion of the hot water supply connection member 20 that protrudes upward from its branch is connected to the hot water filling control unit 60.

[0089] As shown in Figure 3, the hot water filling control unit 60 includes a hot water filling solenoid valve 61, check valves 62A and 62B, and an atmospheric release valve 63.

[0090] As shown in Figures 5 and 6, one end of the hot water supply pipe P6 is connected to the hot water connection port 60H1 of the hot water supply control unit 60. As shown in Figures 3 and 5, the other end of the hot water supply pipe P6 is connected upstream of the pump 69 in the bath return piping P3, which will be described later.

[0091] The hot water filling solenoid valve 61 switches between a hot water filling open state, which supplies water supplied to the hot water filling control unit 60 to the hot water filling supply pipe P6, and a hot water filling closed state, which does not supply water supplied to the hot water filling control unit 60 to the hot water filling supply pipe P6.

[0092] The atmospheric release valve 63 of the hot water supply control unit 60 is connected to the upstream side of the water volume servo 52 in the water volume control unit 50 via a narrow connecting pipe P7. In addition, the atmospheric release valve 63 is connected to the drain side of the neutralizer 48 via a connecting pipe P8.

[0093] <Piping to the bath, piping to the bath and pump> As shown in Figures 3 and 5, the water heater 1 is equipped with a bath return pipe P3, an intermediate pipe P31, a bath supply pipe P4, and a pump 69.

[0094] The bath return pipe P3, intermediate pipe P31, bath supply pipe P4, and pump 69 are housed within the housing 8. In the width direction, the bath return pipe P3, intermediate pipe P31, bath supply pipe P4, and pump 69 are located on the second side, i.e., the left side, which is the other 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.

[0095] The upstream end of the bath return pipe P3 is connected to a bath return connecting member 73 located on the left side of the underside of the housing body 8A. The bath return connecting member 73 is connected to the suction port of the bathtub 4 via an external pipe 73A.

[0096] The downstream end of the bath return pipe P3 is located above the upstream end of the bath return pipe P3. The downstream end of the bath return pipe P3 is connected to the inlet of the heat transfer tube 42B1 of the second auxiliary heat exchanger 42B.

[0097] A pump 69 is connected to the bath return pipe P3, and the other end of the hot water supply pipe P6 is connected upstream of the pump 69.

[0098] The upstream end of intermediate pipe P31 is connected to the outlet of heat transfer tube 42B1 of the second auxiliary heat exchanger 42B. The downstream end of intermediate pipe P31 is located below the upstream end of intermediate pipe P31. The downstream end of intermediate pipe P31 is connected to the inlet of heat transfer tube 42A1 of the second main heat exchanger 42A.

[0099] The intermediate section of the bath return pipe P3 and the intermediate section of the intermediate pipe P31 are connected via a thin connecting pipe P32.

[0100] The upstream end of the bath supply pipe P4 is connected to the outlet of the heat transfer tube 42A1 of the second main heat exchanger 42A. The downstream end of the bath supply pipe P4 is located below the upstream end of the bath supply pipe P4. The downstream end of the bath supply pipe P4 is connected to the bath supply connecting member 74 located on the left side of the lower surface of the housing body 8A. The bath supply connecting member 74 is connected to the hot water outlet of the bathtub 4 via the external pipe 74A.

[0101] <Microbubble Generator> As shown in Figures 2 to 7, the water heater 1 is further equipped with a microbubble generator 9. The microbubble generator 9 is connected to the middle of the hot water pipe P2 within the housing 8. In the width direction, the microbubble generator 9 is located to the first side, i.e., to the right, 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.

[0102] 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.

[0103] The microbubble generator 9 is a device that generates microbubbles in the hot water flowing inside. These microbubbles originate from air and other gases already dissolved in the hot water, and therefore no external gas supply is required.

[0104] In this embodiment, the microbubble generator 9 is a so-called "microfine bubble generator" that generates microbubbles containing bubbles with a diameter of less than 1 μm in the hot water flowing inside. Therefore, the microbubble generator 9 has the configuration described below.

[0105] As shown in Figure 8, the microbubble generator 9 has a main body 90, an inlet 91, and an outlet 92. The main body 90, the inlet 91, and the outlet 92 are each made of separate parts. In this embodiment, the main body 90, the inlet 91, and the outlet 92 are each made of a resin that has heat resistance to high-temperature water.

[0106] The main body 90 is a roughly cylindrical shape centered on the axis X9. The main body 90 is connected to the inlet 91 on one side in the direction of the axis X9 and to the outlet 92 on the other side in the direction of the axis X9.

[0107] The inlet portion 91 has a fitting portion 91A that engages with the main body portion 90, and is fastened to the main body portion 90 by a plurality of screws 91B. The inlet portion 91 is bent upward from the fitting portion 91A. At the end of the inlet portion 91 opposite to the fitting portion 91A, an inlet 91H is formed, centered on an axis that intersects with the axis X9.

[0108] The outlet section 92 has a fitting section 92A that engages with the main body section 90, and is fastened to the main body section 90 by a plurality of screws 92B. At the end of the outlet section 92 opposite to the fitting section 92A, an outlet 92H is formed centered on the axis X9.

[0109] The main body 90 incorporates a venturi member 93 and a plurality of stirring members 94. Both the venturi member 93 and each stirring member 94 are made of resin that has heat resistance to high-temperature water. The venturi member 93 is located on the inlet side 91, and each stirring member 94 is located on the outlet side 92.

[0110] The venturi member 93 has multiple venturi flow paths 93A formed within it. 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 constricted portion in the middle, a constricted flow path that narrows in diameter from the inlet 91 side toward the constricted portion, and an expanding flow path that widens in diameter from the constricted portion toward the outlet 92 side.

[0111] Each stirring member 94 has multiple blades 94A formed on it. Each blade 94A is arranged at equal intervals in the circumferential direction of the axis X9 and is inclined with respect to the axis X9.

[0112] The main body 90 generates fine bubbles containing bubbles with a diameter of less than 1 μm in the hot water flowing inside, using the Venturi member 93 and each stirring member 94. In particular, increasing the number of stirring members 94 arranged in series makes it easier to generate bubbles with a diameter of less than 1 μm, and accordingly, the length L90 of the main body 90 in the axial direction X9 increases.

[0113] The length L90 of the main body 90 in the direction of the axis X9 is greater than the outer diameter D90 of the main body 90. In other words, the microbubble generator 9 has a roughly cylindrical shape in which the length in the direction of the axis X9 is greater than the outer width (outer diameter). In this embodiment, the length L90 is more than twice the outer diameter D90.

[0114] As shown in Figures 4 to 7, the microbubble generator 9 is connected to the middle of the hot water supply pipe P2 with its axis X9 direction inclined. When the microbubble generator 9 is viewed along the width direction, the axis X9 direction is inclined such that the inlet 91H is located above the outlet 92H. In this embodiment, the axis X9 direction extends approximately parallel to the front-back and up-down directions.

[0115] In this state, one direction in the axis X9 direction is rearward, and the other direction in the axis X9 direction is forward. The outlet 92H is located in front of the inlet 91H. The inlet 91H is located behind the outlet 92H and opens vertically upward.

[0116] The inlet 91H is located on one side in the direction of the axis X9, that is, behind the main body 90, and is connected to the upstream side P2U of the hot water supply pipe P2. Hot water flows into the inlet 91H from the upstream side P2U of the hot water supply pipe P2.

[0117] The outlet 92H is located on the other side in the direction of the axis X9, that is, in front of the main body 90, and is connected to the downstream side P2D of the hot water supply pipe P2. The outlet 92H discharges hot water containing fine bubbles to the downstream side P2D of the hot water supply pipe P2.

[0118] As shown in Figure 4, the upstream side P2U of the hot water supply pipe P2 and the inlet 91 are fixed together with a metal clip 91C in a single action. Similarly, the downstream side P2D of the hot water supply pipe P2 and the outlet 92 are fixed together with a metal clip 92C in a single action.

[0119] Figure 4 shows the flame ports 31F and 32F, and in Figure 7, the height of the flame ports 31F and 32F is indicated by height H1. Thus, the microbubble generator 9 is located below the flame ports 31F and 32F of the burners 31B and 32B.

[0120] In Figure 7, the height of the downstream hot water supply channel from the point where the hot water supply pipe P2 connects to the outlet 92H at the downstream side P2D to the hot water supply connection member 20 is indicated by height H2. The outlet 92H is located at a height equal to or greater than the height H2 of the downstream hot water supply channel.

[0121] In Figure 7, the height of the internal flow path of the hot water filling control unit 60 is indicated by height H3. The microbubble generator 9 is located above the water volume control unit 50 and also above the height H3 of the internal flow path of the hot water filling control unit 60.

[0122] <Hot water supply operation> When a user performs an operation to supply hot water, such as opening a hot water outlet tap at a hot water supply terminal, such as a mixing faucet installed in the kitchen or a mixing faucet and shower installed in the bathroom, the bypass servo 51 is normally in the bypass closed state, and the first combustion device 31 starts combustion to generate high-temperature gas. However, the bypass servo 51 may also be set to the bypass open state for special purposes, such as maintaining a high temperature for the hot water outlet from the first main heat exchanger 41A.

[0123] Water supplied from a water source (not shown) passes through the water supply channel 10S, water supply connection member 10, water flow control unit 50, water supply pipe P1, heat transfer tube 41B1 of the first auxiliary heat exchanger 41B, intermediate water supply pipe P11, and heat transfer tube 41A1 of the first main heat exchanger 41A. At this time, the water is heated by the first auxiliary heat exchanger 41B and the first main heat exchanger 41A to become hot water. This hot water then passes through the hot water supply pipe P2, and along the way, microbubbles containing bubbles with a diameter of less than 1 μm are generated by the microbubble generator 9.

[0124] Furthermore, the hot water passes through the hot water connection member 20 and the hot water supply passage 20S, and flows out from the hot water outlet tap at the hot water supply terminal, containing fine bubbles.

[0125] <Water filling operation> When a user performs an operation to fill the bathtub, such as pressing the bathtub filling button on a hot water remote control installed in the kitchen or bathroom, the first combustion device 31 starts combustion and generates high-temperature gas. The bypass servo 51 switches to the bypass open state depending on the situation. The bathtub filling solenoid valve 61 switches to the bathtub filling open state. The pump 69 is stopped.

[0126] Water supplied from a water source (not shown) passes through the water supply pipe P1, becomes hot water in the same way as the hot water supply operation, and flows into the hot water pipe P2. Also, when the bypass servo 51 is in the bypass open state, a portion of the water supplied from the water source (not shown) flows into the hot water pipe P2 via the bypass pipe P21.

[0127] The hot water then passes through the hot water supply pipe P2, and along the way, the microbubble generator 9 generates microbubbles containing bubbles with a diameter of less than 1 μm.

[0128] Furthermore, the hot water passes through the hot water supply connection member 20, the hot water filling control unit 60, and the hot water supply pipe P6, and flows upstream of the pump 69 in the bath return pipe P3. Then, a portion of the hot water passes through the pump 69, the heat transfer tube 42B1 of the second auxiliary heat exchanger 42B, the intermediate pipe P31, the heat transfer tube 42A1 of the second main heat exchanger 42A, the bath supply pipe P4, the bath supply connection member 74, and the external pipe 74A to reach the bathtub 4. The other portion of the hot water passes through the bath return pipe P3, the bath return connection member 73, and the external pipe 73A to reach the bathtub 4. In this way, the hot water that has passed through the two paths is stored in the bathtub 4, containing fine bubbles.

[0129] <Reheating operation> When a user performs an operation to reheat the water, for example, by pressing the reheat button on a water heater remote control installed in the kitchen or bathroom, the second combustion device 32 starts combustion and generates high-temperature gas. The water filling solenoid valve 61 is in the water filling closed state.

[0130] Pump 69 operates to circulate the hot water stored in the bathtub 4 in the following order: external piping 73A, bath return connection member 73, bath 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, bath supply piping P4, bath supply connection member 74, and external piping 74A. As a result, the circulating hot water is reheated by the second auxiliary heat exchanger 42B and the second main heat exchanger 42A.

[0131] <Effects and Effects> In the water heater 1 of Example 1, as shown in Figures 4 and 7, the microbubble generator 9 housed within the casing 8 is positioned below the flame ports 31F and 32F of the burners 31B and 32B. This configuration reduces the need for various measures to suppress the influence of heat transferred 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. For example, measures such as constructing the microbubble generator 9 from a highly heat-resistant resin or metal can be reduced. As a result, this water heater 1 can reduce material costs and processing costs for the microbubble generator 9.

[0132] Therefore, the water heater 1 of Example 1, with its configuration that houses the microbubble generator 9 within the housing 8, can suppress the increase in manufacturing costs.

[0133] Furthermore, in this water heater 1, as shown in Figures 2 to 4, the microbubble generator 9 is located to the first side, i.e., to the right, 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, this water heater 1 can prevent the piping between the hot water pipe P2 and the microbubble generator 9 from becoming excessively long, and thus the space inside the housing 8 can be used efficiently.

[0134] Furthermore, in this water heater 1, as shown in Figure 7, the inlet 91H is located above the outlet 92H. The outlet 92H is located at a height of H2 or greater than the height of the downstream hot water flow path from the part of the hot water pipe P2D that connects to the outlet 92H to the hot water connection member 20. With this configuration, the vertical positional relationship is inlet 91H > outlet 92H ≥ height H2 of the downstream hot water flow path. Therefore, when draining water from the microbubble generator 9, this water heater 1 can drain water from the hot water connection member 20 without providing a separate draining circuit.

[0135] Furthermore, in this water heater 1, the microbubble generator 9 is located above the water volume control unit 50. This configuration makes it easy to access or remove the water volume control unit 50 by removing the portion of the hot water pipe P2 located downstream of the microbubble generator 9, i.e., the downstream P2D of the hot water pipe P2. As a result, this water heater 1 achieves improved maintainability.

[0136] Furthermore, in this water heater 1, when the microbubble generator 9 is viewed along the width direction, it is inclined such that the inlet 91H is located above the outlet 92H in the direction of the axis X9. This configuration makes it possible to appropriately position the long microbubble generator 9, which is long in the direction of the axis X9, below the flame ports 31F and 32F of the burners 31B and 32B. In addition, because the microbubble generator 9 is inclined such that the inlet 91H is located above the outlet 92H, it is also easy to drain water from the microbubble generator 9. As a result, this water heater 1 can achieve improved resistance to freezing.

[0137] Furthermore, in this water heater 1, the inlet 91H is located behind the outlet 92H and opens vertically upward. This configuration makes it easier to see from the front the connection between the upstream side P2U of the hot water pipe P2 and the inlet section 91 where the inlet 91H is formed, and also makes it easy to reach and touch the connection through the housing opening 8H. As a result, this water heater 1 can achieve even greater maintainability.

[0138] Furthermore, in this water heater 1, the outlet 92H is located in front of the inlet 91H. The hot water connection port 20H1 to which the downstream end of the hot water pipe P2 in the hot water connection member 20 is connected is often opened toward the front side of the housing 8 from the viewpoint of ease of assembly, and this is also the case in this embodiment. Therefore, with the outlet 92H located in front of the inlet 91H, the downstream side P2D of the hot water pipe P2 connected to the outlet 92H can be routed smoothly to the hot water connection port 20H1 of the hot water connection member 20. As a result, this water heater 1 can achieve improved ease of assembly and processing, as well as reduced manufacturing costs.

[0139] Furthermore, in this water heater 1, as shown in Figure 8, the microbubble generator 9 has an inlet 91, an outlet 92, and a main body 90, each composed of separate parts. With this configuration, multiple types of inlet 91 and outlet 92 with different shapes are prepared in advance, and by using the inlet 91 and outlet 92 selected as appropriate from among them, it is possible to easily accommodate various connection and mounting configurations, such as vertical mounting or inlet and outlet in the vertical direction with diagonal mounting.

[0140] (Example 2) As shown in Figures 9 and 10, the water heater 2 of Example 2 employs a water supply pipe P201, a hot water supply pipe P202, and a microbubble generator 209 instead of the water supply pipe P1, hot water supply pipe P2, and microbubble generator 9 of the water heater 1 of Example 1. The water supply pipe P201 is an example of the "specific pipe" of the present invention.

[0141] The other components of Example 2 are the same as those of Example 1. Therefore, components identical to those of Example 1 are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0142] As shown in Figure 9, in Embodiment 2, the microbubble generator 209 is connected to the middle of the water supply pipe P201 within the housing 8. In the width direction, the microbubble generator 209 is located to the first side, i.e., to the right, 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.

[0143] 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.

[0144] The only difference between the water supply pipe P201 and the water supply pipe P1 in Example 1 is that the microbubble generator 209 is connected in the middle of the water supply pipe P201. The other configurations of the water supply pipe P201 are the same as those of the water supply pipe P1 in Example 1.

[0145] The only difference between the hot water supply pipe P202 and the hot water supply pipe P2 in Example 1 is that the hot water supply pipe P202 extends continuously from the upstream end to the downstream end. The other configurations of the hot water supply pipe P202 are the same as those of the hot water supply pipe P2 in Example 1.

[0146] As shown in Figure 10, the microbubble generator 209 has a main body 290, an inlet 291, and an outlet 292, each composed of separate parts.

[0147] The only difference between the main body 290 and the main body 90 in Example 1 (though not shown in the illustration) is that the orientation of the built-in venturi member 93 and each stirring member 94 is reversed compared to Example 1. In other words, the venturi member 93 is located on the inlet 291 side, and each stirring member 94 is located on the outlet 292 side. The other configurations of the main body 290 are the same as those of the main body 90 in Example 1.

[0148] The inlet 291 is the same as the outlet 92 in Example 1. The inlet 291H of the inlet 291 is the same as the outlet 92H in Example 1.

[0149] The outlet section 292 is the same as the inlet section 91 in Example 1. The outlet 292H of the outlet section 292 is the same as the inlet 92H in Example 1.

[0150] The main body 290 is centered on the axis X9, similar to Embodiment 1. However, in Embodiment 2, one direction in the direction of the axis X9 is changed to the front, and the other direction in the direction of the axis X9 is changed to the rear.

[0151] The main body 290 is connected to the inlet 291 on one side in the direction of the axis X9, and to the outlet 292 on the other side in the direction of the axis X9.

[0152] The microbubble generator 209 has a roughly cylindrical shape, with a length in the axial direction X9 being greater than its outer width (outer diameter). The microbubble generator 209 is connected to the middle of the water supply pipe P201 with an inclination in the axial direction X9. When the microbubble generator 209 is viewed along the width direction, the axial direction X9 is inclined such that the outlet 292H is located above the inlet 291H. In this embodiment, the axial direction X9 extends roughly parallel to the front-rear and up-down directions.

[0153] The inlet 291H is located forward of the outlet 292H. The outlet 292H is located behind the inlet 291H and opens vertically upward.

[0154] The inlet 291H is located in one direction in the axis X9 direction, that is, forward of the main body 290, and is connected to the upstream side P201U of the water supply pipe P201. Water flows into the inlet 291H from the upstream side P201U of the water supply pipe P201.

[0155] The outlet 292H is located on the other side in the direction of the axis X209, that is, behind the main body 290, and is connected to the downstream side P201D of the water supply pipe P201. The outlet 292H discharges water containing fine bubbles to the downstream side P201D of the water supply pipe P201.

[0156] In Figure 10, the height of the flame ports 31F and 32F of burners 31B and 32B is indicated by height H1. The microbubble generator 209 is located below the flame ports 31F and 32F of burners 31B and 32B.

[0157] In Figure 10, the height of the upstream water supply channel from the water supply connection member 10 to the inlet 291H on the upstream side P201U of the water supply pipe P201 is indicated by height H4. The inlet 291H is located at a height of H4 or higher than the height of the upstream water supply channel.

[0158] In Figure 10, the height of the internal flow path of the hot water filling control unit 60 is indicated by height H3. The microbubble generator 209 is located above the water volume control unit 50 and also above the height H3 of the internal flow path of the hot water filling control unit 60.

[0159] The water heater 2 of Embodiment 2, with this configuration, can dispense hot water containing fine bubbles through hot water supply and bath filling operations, similar to the water heater 1 of Embodiment 1.

[0160] <Effects and Effects> In the water heater 2 of Example 2, similar to the water heater 1 of Example 1, the microbubble generator 209 housed within the casing 8 is positioned below the flame ports 31F and 32F of the burners 31B and 32B. This configuration reduces the need for various measures to suppress the heat transfer 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. As a result, this water heater 2 can reduce material and processing costs for the microbubble generator 209.

[0161] Therefore, the water heater 2 of Example 2 can also suppress the increase in manufacturing costs by having a configuration in which the microbubble generator 209 is housed within the housing 8.

[0162] Furthermore, in this water heater 2, the microbubble generator 209 is located to the first side, i.e., to the right, 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, this water heater 2 can prevent the piping between the water supply pipe P201 and the microbubble generator 209 from becoming excessively long, thus enabling efficient use of space within the housing 8.

[0163] Furthermore, in this water heater 2, the outlet 292H is located above the inlet 291H. The inlet 291H is located at a height of H4 or more above the height of the upstream water supply channel from the water supply connection member 10 to the part of the water supply pipe P201 upstream P201U that connects to the inlet 291H. With this configuration, the vertical positional relationship is outlet 292H > inlet 291H ≥ height H4 of the upstream water supply channel. For this reason, when draining water from the microbubble generator 209, this water heater 2 can drain water from the water supply connection member 10 without providing a separate draining circuit.

[0164] Furthermore, in this water heater 2, the microbubble generator 209 is located above the water volume control unit 50. This configuration makes it easy to access or remove the water volume control unit 50 by removing the upstream portion of the water supply pipe P201 located above the microbubble generator 209, i.e., the upstream P201U of the water supply pipe P201. As a result, this water heater 2 achieves improved maintainability.

[0165] Furthermore, in this water heater 2, when the microbubble generator 209 is viewed along the width direction, it is inclined in the axial direction X9 such that the outlet 292H is located above the inlet 291H. This configuration allows for the proper placement of the long microbubble generator 209, which is long in the axial direction X9, below the flame ports 31F and 32F of the burners 31B and 32B. In addition, because the microbubble generator 209 is inclined so that the outlet 292H is located above the inlet 291H, water can be easily drained from the microbubble generator 209. As a result, this water heater 2 can achieve improved freeze resistance.

[0166] Furthermore, in this water heater 2, the outlet 292H is located behind the inlet 291H and opens vertically upward. This configuration makes it easier to see from the front the connection between the downstream side P201D of the water supply pipe P201 and the outlet section 292 where the outlet 292H is formed, and also makes it easy to reach and touch the connection through the housing opening 8H. As a result, this water heater 2 can achieve even greater maintainability.

[0167] Furthermore, in this water heater 2, the inlet 291H is located in front of the outlet 292H. The water supply connection port 50H1 to which the upstream end of the water supply pipe P201 in the water volume control unit 50 is connected is often opened toward the front side of the housing 8 from the standpoint of ease of assembly, and this is also the case in this embodiment. Therefore, with the inlet 291H located in front of the outlet 292H, the upstream side P201U of the water supply pipe P201 connected to the inlet 291H can be routed smoothly to the water supply connection port 50H1 of the water volume control unit 50. As a result, this water heater 2 can achieve improved ease of assembly and processing, as well as reduced manufacturing costs.

[0168] Although the present invention has been described above in reference to Examples 1 and 2, it goes without saying that the present invention is not limited to Examples 1 and 2, and can be applied with appropriate modifications without departing from its spirit.

[0169] The present invention also includes a configuration in which the second combustion device 32 for baths, the second main heat exchanger 42A, the second auxiliary heat exchanger 42B, the hot water filling control unit 60, the bath return pipe P3, the intermediate pipe P31, the bath supply pipe P4, the pump 69, etc. are eliminated from Examples 1 and 2, i.e., a single-function water heater.

[0170] In Examples 1 and 2, the microbubble generators 9 and 209 are located to the first side, i.e., to the right, 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. However, the present invention is not limited to this configuration. For example, the microbubble generator may be located to the second side, front, rear, or below the other side of the heat exchanger, as long as it is located below the flame port of the burner.

[0171] In Examples 1 and 2, the fuel for the first combustion device 31 and the second combustion device 32 is a fuel gas such as city gas or propane gas, but the present invention is not limited to this configuration. For example, the fuel for the combustion device may be a liquid such as kerosene.

[0172] In Example 1, the inlet 91H is located behind the outlet 92H and opens vertically upward, but the present invention is not limited to this configuration. For example, the present invention also includes a configuration in which the orientation of the microbubble generator 9 in the water heater 1 of Example 1 is changed so that the outlet 92H is located behind the inlet 91H and opens vertically downward. In this case, the connection between the downstream side P2D of the hot water pipe P2 and the outlet 92H becomes easier to see from the front, and it becomes easier to reach and touch the connection through the housing opening 8H, thus further improving maintainability.

[0173] In Example 2, the outlet 292H is located behind the inlet 291H and opens vertically upward, but the present invention is not limited to this configuration. For example, the present invention also includes a configuration in which the orientation of the microbubble generator 209 in the water heater 2 of Example 2 is changed so that the inlet 291H is located behind the outlet 292H and opens vertically downward. In this case, the connection between the upstream side P201U of the water supply pipe P201 and the inlet 291H becomes easier to see from the front, and it becomes easier to reach and touch the connection through the housing opening 8H, thus further improving maintainability.

[0174] In Examples 1 and 2, the water flow control unit 50 has a bypass servo 51 and a water flow servo 52, but the present invention is not limited to this configuration. The water flow control unit can have any configuration as long as it can control the flow rate of water flowing through the water supply pipe, and for example, a configuration in which the water flow control unit has only one of the bypass servo and the water flow servo is also included in the present invention.

[0175] In Examples 1 and 2, the microbubble generators 9 and 209 have a substantially cylindrical shape in which the length in the axial direction X9 is greater than the outer diameter, but the present invention is not limited to this configuration. For example, the microbubble generator may have a substantially cylindrical shape such as a square tube or a polygonal tube, as long as the length in the axial direction is greater than the outer width.

[0176] In Examples 1 and 2, the axis X9 direction extends substantially parallel to the front-rear and up-down directions, but the present invention is not limited to this configuration. For example, the axis direction may be inclined with respect to the front-rear and up-down directions. [Industrial applicability]

[0177] The present invention can be used, for example, in water heaters that have only a hot water supply function, water heaters that have both a hot water supply function and a bath reheating function, and hot water heaters that have a hot water supply function and a function to circulate hot water between them and heating equipment. [Explanation of Symbols]

[0178] 1, 2... Water heater 8A...Main unit 8H... Enclosure opening 8B…Front panel 8…Cabinet 31C, 32C... Combustion chamber 31B, 32B... Burner 31F, 32F... Burner flame nozzles 31, 32... Combustion devices (31... First combustion device, 32... Second combustion device) 41A, 41B, 42A, 42B...Heat exchanger (41A...1st main heat exchanger, 41B...1st sub heat exchanger, 42A...2nd main heat exchanger, 42B...2nd sub heat exchanger) P1, P201…Water supply pipe P201U... Upstream side of the water supply pipe P201D... Downstream side of the water supply pipe P2, P202... Hot water pipes P2U…Upstream side of the hot water pipe P2D… Downstream side of the hot water pipe 10S… Water supply channel 10...Water supply connection component 20S... Hot water supply line 20... Hot water connection component 50...Water volume control unit 9,209...Microbubble generator X9…Axis center 91H, 291H…Inlet 92H, 292H...Outlet 91, 291...Inflow part 92,292...Outlet section 90, 290... Main unit

Claims

1. A housing having a housing opening that opens to the front and a roughly box-shaped housing body that is recessed toward the rear, and a front plate that covers the housing opening, A combustion device comprising a combustion chamber and a burner whose flame port is located within the combustion chamber, which generates high-temperature gas, is housed within the aforementioned enclosure. A heat exchanger is housed above the combustion chamber within the aforementioned housing and heats the water passing through it with the high-temperature gas to convert it into hot water. A water supply pipe is housed within the aforementioned housing, located on the first side which is one side of the heat exchanger in the width direction perpendicular to the front-rear and up-down directions, extending in the up-down direction and connected to the heat exchanger, A hot water supply pipe is housed within the aforementioned housing, positioned to the first side of the heat exchanger in the width direction, extending in the vertical direction, and connected to the heat exchanger. A water supply connecting member located on the lower surface of the housing body, for connecting the water supply pipe and the water supply channel located outside the housing, A hot water supply connecting member located on the lower surface of the housing body for connecting the hot water supply pipe and the hot water supply passage located outside the housing, A water flow control unit is provided between the water supply connection member and the water supply pipe, which controls the flow rate of water flowing through the water supply pipe. A water supply control unit, housed within the aforementioned enclosure, controls the supply of hot water from the hot water supply pipe to the bathtub in order to fill the bathtub with hot water, In a water heater, The housing further comprises a microbubble generator connected to a specific pipe, which is either the water supply pipe or the hot water supply pipe, having a roughly cylindrical shape with an axial length greater than its outer width, and generating microbubbles in the hot water simply by hot water flowing through it. The water heater is characterized in that the microbubble generator is located to the first side of the heat exchanger in the width direction and is located above the water volume control unit and the hot water filling control unit.

2. The water volume control unit and the hot water filling control unit are located in the width direction closer to the first side of the heat exchanger than to the side opposite to the first side of the heat exchanger, according to claim 1.

3. The specified pipe is the hot water supply pipe, The hot water supply control unit is located on the first side of the heat exchanger in the width direction, The water heater according to claim 2, wherein a part of the water filling control unit is located directly below the microbubble generator.

4. The specified pipe is the hot water supply pipe, The microbubble generator is located on one side in the axial direction and connected to the upstream portion of the hot water supply pipe, and has an inlet into which hot water flows in from the upstream portion of the hot water supply pipe, It has an outlet located on the other side in the axial direction and connected to the downstream portion of the hot water supply pipe, which causes the hot water containing the fine bubbles to flow out to the downstream portion of the hot water supply pipe, The outlet is located forward and below the inlet. The hot water supply connection member is divided into a portion having a hot water supply connection port that opens toward the front side of the housing and a portion that connects to the hot water supply control unit. The water heater according to claim 2 or 3, wherein the downstream end of the portion located on the downstream side of the hot water supply pipe is connected to the hot water supply connection port.

5. The specified pipe is the hot water supply pipe, The microbubble generator is located on one side in the axial direction and connected to the upstream portion of the hot water supply pipe, and has an inlet into which hot water flows in from the upstream portion of the hot water supply pipe, It has an outlet located on the other side in the axial direction and connected to the downstream portion of the hot water supply pipe, which causes the hot water containing the fine bubbles to flow out to the downstream portion of the hot water supply pipe, The bypass pipe is housed within the housing and located to the first side of the heat exchanger in the width direction, with its upstream end connected to the water volume control unit and its downstream end located above the upstream end and connected to the middle of the upstream portion of the hot water supply pipe, and the bypass pipe is capable of allowing water to flow from the water volume control unit to the upstream portion of the hot water supply pipe. The microbubble generator is configured such that at least the outlet is located below the flame port. The water heater according to any one of claims 2 to 4, wherein a portion of the bypass pipe is located below the flame port and above the outlet of the microbubble generator.

6. The specified pipe is the hot water supply pipe, The microbubble generator is located on one side in the axial direction and connected to the upstream portion of the hot water supply pipe, and has an inlet into which hot water flows in from the upstream portion of the hot water supply pipe, It has an outlet located on the other side in the axial direction and connected to the downstream portion of the hot water supply pipe, which causes the hot water containing the fine bubbles to flow out to the downstream portion of the hot water supply pipe, The bypass pipe is housed within the housing and located to the first side of the heat exchanger in the width direction, with its upstream end connected to the water volume control unit and its downstream end located above the upstream end and connected to the middle of the upstream portion of the hot water supply pipe, and the bypass pipe is capable of allowing water to flow from the water volume control unit to the upstream portion of the hot water supply pipe. The upstream end of the bypass pipe is located below the inlet and outlet of the microbubble generator. The downstream end of the bypass pipe is located above the inlet and outlet of the microbubble generator. The water heater according to any one of claims 2 to 4, wherein a portion of the bypass pipe, including the downstream end, is located in the width direction closer to the heat exchanger than the outlet of the microbubble generator.

7. The specified pipe is the water supply pipe, The microbubble generator is located on one side in the axial direction and connected to the upstream portion of the water supply pipe, and has an inlet into which water flows in from the upstream portion of the water supply pipe, It has an outlet located in the other axial direction and connected to the downstream portion of the water supply pipe, which causes the water containing the fine bubbles to flow out to the downstream portion of the water supply pipe, The inlet is located forward and below the outlet. The water volume control unit has a water supply connection port that opens toward the front side of the housing, The water heater according to claim 2, wherein the upstream end of the portion located on the upstream side of the water supply pipe is connected to the water supply connection port.

8. The water heater according to any one of claims 1 to 7, wherein the microbubble generator is located below the heat exchanger.

Images