hot water supply

Abstract

The present invention provides a hot water supply device that incorporates a microbubble generator within a frame, thereby suppressing the increase in manufacturing costs. A hot water supply unit 1 includes: a frame 8, combustion devices 31 and 32, heat exchangers 41A to 42B, a water supply pipe P1, a hot water supply pipe P2, a water supply connection member 10, a hot water supply connection member 20, and a water flow control unit 50. The hot water supply unit 1 further includes: a microbubble generator 9; this microbubble generator 9 is connected within the frame 8 to one of the water supply pipes P1 and the hot water supply pipe P2, i.e., a specific pipe P2, forming a generally cylindrical shape with a length in the axial X9 direction greater than its outer width, and generates microbubbles in the hot water flowing inside. The microbubble generator 9 has: an inlet 91H located on one side in the axial X9 direction, supplying hot water to flow 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, allowing the hot water containing microbubbles to flow out towards the downstream side P2D of the specific pipe P2. The microbubble generator 9 is located closer to and below the flame outlets 31F and 32F of the burners 31B and 32B.

Description

Technical Field

[0001] This invention relates to a hot water supply device. Prior Technology

[0002] Patent document 1 discloses an example of a conventional hot water supply device. This hot water supply device includes a frame, a combustion device, and a heat exchanger.

[0003] The frame has a frame body. The frame body has a generally box-shaped structure with a frame opening that is open at the front and recessed towards the rear. Although not shown in Patent Document 1, the frame has a front plate that covers the frame opening. A combustion device is housed within the frame. 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 frame. The heat exchanger heats and converts water passing through it into hot water using the high-temperature gas.

[0004] As shown in Patent Document 1, Figure 1, etc., the hot water supply device includes: a water supply pipe, a hot water supply pipe, a water supply connection component, and a hot water supply connection component.

[0005] The water supply pipe and hot water supply pipe are housed within the frame and connected to the heat exchanger. The water supply connection component and the hot water supply connection component are located below the frame body. The water supply connection component connects the water supply pipe to the water supply path located outside the frame. The hot water supply connection component connects the hot water supply pipe to the hot water supply path located outside the frame. Furthermore, a water flow control unit is provided between the water supply connection component and the water supply pipe, which controls 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 disposed midway in a pipe leading to a faucet, such as a shower fixture or a water tap. The microbubble generator is formed as a generally cylindrical shape with an axial length 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 greater than its outer diameter, the easier it is to form fine microbubbles generated by the hot water. [Previous Technical Documents] [Patent Literature]

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-55929 Patent Document 2: Japanese Patent Application Publication No. 2020-171914 Summary of the Invention

[0008] (The problem the invention aims to solve)

[0009] Here, we discuss a technical solution for incorporating a conventional microbubble generator within the frame of a conventional hot water supply unit. However, in this case, because the microbubble generator has a relatively long axial length, its volume tends to increase. Furthermore, due to the limited space and shape of the installation location, it is easily affected by the combustion device and heat exchanger. Therefore, a hot water supply unit that incorporates a microbubble generator within a frame requires various countermeasures to suppress the influence from the combustion device and heat exchanger, which may result in increased manufacturing costs.

[0010] The present invention was made in view of the above-mentioned conventional practical situation, and it can solve the above-mentioned problems by providing a hot water supply device that can house a microbubble generator in a frame and suppress the increase in manufacturing costs. (Technical means to solve the problem)

[0011] The hot water supply device of the present invention comprises: A frame having a frame body and a front panel; the frame body has a frame opening that is open at the front and is generally box-shaped and recessed towards the rear; the front panel covers the frame opening; A combustion device, housed within the aforementioned frame, includes a combustion chamber and a burner with its flame nozzle located within the combustion chamber, for generating high-temperature gas; A heat exchanger is housed above the combustion chamber within the aforementioned frame, and uses the high-temperature gas to heat the water passing through it and convert it into hot water. A water supply pipe is housed within the aforementioned frame and is located on one side of the heat exchanger, i.e., the first side, in a width direction orthogonal to the front-back and vertical directions, and extends in the vertical direction to connect with the heat exchanger. A hot water supply pipe is housed within the aforementioned frame and is located on the aforementioned first side of the aforementioned heat exchanger in the aforementioned width direction, and extends in the aforementioned vertical direction to connect with the aforementioned heat exchanger; A water supply connection component, located below the frame body, is used to connect the water supply pipe to the water supply path located outside the frame. A hot water supply connection component, located below the aforementioned frame body, is used to connect the aforementioned hot water supply pipe to a hot water supply path located outside the aforementioned frame; and A water flow control unit is provided between the aforementioned water supply connection member and the aforementioned water supply pipe to control the flow rate of water flowing in the aforementioned water supply pipe; The hot water supply unit is characterized by: Furthermore, it incorporates a microbubble generator, which is connected within the aforementioned frame to one of the aforementioned water supply pipes and hot water supply pipes (i.e., a specific pipe). This generator is formed as a roughly cylindrical shape, with its axial length greater than its outer width, and produces microbubbles on the hot water flowing within it. The aforementioned microbubble generator has an inlet and an outlet; the inlet is located on one side of the aforementioned axial direction, allowing the hot water to flow in from the upstream side of the aforementioned specific pipe; the outlet is located on the other side of the aforementioned axial direction, allowing the hot water containing the aforementioned microbubbles to flow out towards the downstream side of the aforementioned specific pipe. The aforementioned microbubble generator is located closer to and below the aforementioned flame outlet.

[0012] In the hot water supply device of the present invention, by positioning the microbubble generator housed within a frame closer to and below the flame outlet of the burner, the necessity for various countermeasures to suppress the thermal effects conducted from the self-ignition device and heat exchanger to the microbubble generator can be reduced. For example, the necessity for constructing the microbubble generator using highly heat-resistant resins or metals can be reduced. As a result, the hot water supply device can reduce the material and processing costs of the microbubble generator.

[0013] Therefore, the hot water supply device of the present invention can suppress the increase in manufacturing costs by housing the microbubble generator in the frame.

[0014] It is preferable that the microbubble generator is located on the first side of the heat exchanger in the width direction.

[0015] According to this configuration, the microbubble generator is positioned on the same side as the main pipe in the width direction. Therefore, the hot water supply unit can prevent the piping from becoming too long between the main pipe and the microbubble generator, thus making efficient use of the space within the frame.

[0016] For a specific piping system, the hot water supply pipe is preferred. It is preferable that the inlet is located above the outlet. Furthermore, it is preferable that the outlet is located at a height above the downstream side of the hot water supply flow path, from the portion where the hot water supply pipe connects to the outlet to the hot water supply connection member.

[0017] 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, the hot water supply unit does not need to be equipped with a separate drainage circuit; drainage can be achieved directly from the hot water supply connection component.

[0018] In the above situation, it is preferable that the microbubble generator is located above the water flow control unit.

[0019] Based on this configuration, by removing the portion of the hot water supply pipe located downstream of the microbubble generator, it is easy to access or remove the water flow control unit. Therefore, this hot water supply unit achieves improved maintainability.

[0020] A specific piping system for hot water supply is preferred. Furthermore, when observing the microbubble generator along its width, it is preferable that the axial direction is tilted so that the inlet is located closer to the outlet and above it.

[0021] According to this configuration, a microbubble generator with a relatively long axial length can be appropriately positioned closer to the bottom of the burner's flame outlet. Furthermore, since the microbubble generator is tilted with its inlet located closer to the top of the outlet, drainage within the microbubble generator can be easily implemented. As a result, the hot water supply unit achieves improved freeze resistance.

[0022] In the above situation, it is preferable that one of the inlet and outlet is located closer to the rear of the other inlet and outlet, and opens in the vertical direction.

[0023] According to this configuration, when the inlet is located further rear than the outlet, the inlet opens upwards in the vertical direction. Therefore, the connection between the upstream side of the hot water supply pipe and the inlet is easily visible from the front of the hot water supply unit, and the connection can be easily reached through the frame opening. Furthermore, when the outlet is located further rear than the inlet, the outlet opens downwards in the vertical direction. Therefore, the connection between the downstream side of the hot water supply pipe and the outlet is easily visible from the front of the hot water supply unit, and the connection can be easily reached through the frame opening. As a result, the maintainability of the hot water supply unit is further improved.

[0024] Furthermore, in the above situation, it is better to have the outlet located closer to the front than the inlet.

[0025] From an assembly perspective, the hot water supply connection port, where the hot water supply connection component connects to the hot water supply pipe, is often oriented towards the front of the frame. Therefore, by arranging the outlet closer to the front than the inlet, the downstream side of the hot water supply pipe connected to the outlet can be easily routed to the hot water supply interface of the hot water supply connection component. As a result, this hot water supply unit achieves improved assembly and manufacturability, as well as reduced manufacturing costs.

[0026] A specific piping system is preferred for the water supply pipe. Preferably, the outlet is located above the inlet. Furthermore, it is preferable that the inlet is located at a height above the upstream water supply path from the water supply connection member to the part of the water supply pipe that connects to the inlet.

[0027] 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, the hot water supply unit does not need to be equipped with a separate drainage circuit; drainage can be achieved directly from the hot water supply connection component.

[0028] In the above situation, it is preferable for the microbubble generator to be located closer to and above the water flow control unit.

[0029] Based on this configuration, by removing the portion of the water supply pipe located upstream of the microbubble generator, it is easy to access or remove the water flow control unit. As a result, the maintainability of this hot water supply unit is improved.

[0030] A specific piping system is preferred for water supply. Furthermore, when observing the microbubble generator along its width, it is preferable that the axis is tilted so that the outlet is located closer to the inlet than above it.

[0031] According to this configuration, a microbubble generator with a relatively long axial length can be appropriately positioned closer to the bottom of the burner's flame outlet. Furthermore, since the microbubble generator is tilted with its outlet located closer to the top than its inlet, drainage within the microbubble generator can also be easily implemented. As a result, the hot water supply unit achieves improved freeze resistance.

[0032] In the above situation, it is preferable that one of the inlet and outlet is located closer to the rear of the other inlet and outlet and opens in the vertical direction.

[0033] 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 connection between the upstream side of the water supply pipe and the inlet is easily visible from the front of the hot water supply unit, and the connection can be easily reached through the frame opening. Furthermore, when the outlet is located further rear than the inlet, the outlet opens upwards in the vertical direction. Therefore, the connection between the downstream side of the water supply pipe and the outlet is easily visible from the front of the hot water supply unit, and the connection can be easily reached through the frame opening. As a result, the maintainability of this hot water supply unit is further improved.

[0034] Furthermore, in the above situation, it is preferable that the inlet is located closer to the outlet than the inlet.

[0035] From an assembly efficiency perspective, the water supply connection port between the water control unit and the water supply pipe is often oriented towards the front of the frame. Therefore, by arranging the inlet closer to the front than the outlet, the upstream side of the water supply pipe connected to the inlet can be easily routed to the water supply connection port of the water control unit. As a result, this hot water supply unit achieves improved assembly efficiency, manufacturability, and reduced manufacturing costs.

[0036] 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 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, generating microbubbles in the hot water flowing inside. Furthermore, it is preferable that the inlet portion, outlet portion, and body portion are each constructed using different components.

[0037] According to this configuration, by pre-preparing multiple types of inflow and outflow sections of different shapes, and using the inflow and outflow sections appropriately selected from them, various connection and installation methods, such as vertical installation or inclined installation, can easily correspond to vertical inflow and outflow. (Compared to the effectiveness of previous technologies)

[0038] According to the hot water supply device of the present invention, the microbubble generator can be housed within the frame, thereby suppressing the increase in manufacturing costs. Simple Explanation of the Diagram

[0039] Figure 1 is a perspective view of the hot water supply unit in Embodiment 1. Figure 2 is a perspective view of the hot water supply unit of Embodiment 1 after the front panel has been removed. Figure 3 is a schematic diagram of the hot water supply unit in Embodiment 1. Figure 4 is a partial perspective view of the combustion chamber, flame nozzle, and microbubble generator of the hot water supply unit of Embodiment 1. Figure 5 is a perspective view of the hot water supply unit of Embodiment 1, after removing the frame body, 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 from Figure 2. Figure 6 is an exploded perspective view of the hot water supply 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 hot water supply unit of Embodiment 1. Figure 7 is a side view of the hot water supply 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 hot water supply unit of Embodiment 1. Figure 8 is an exploded perspective view of the microbubble generator of the hot water supply unit in Embodiment 1. Figure 9 is a schematic diagram of the hot water supply unit in Embodiment 2. Figure 10 shows a side view of the water supply pipe, microbubble generator, water supply connection component, hot water supply connection component, water volume control unit, and hot water injection control unit of the hot water supply unit of Embodiment 2. Implementation

[0040] Hereinafter, with reference to the drawings, embodiments 1 and 2 embodying the present invention will be described.

[0041] (Example 1) As shown in Figure 1, the hot water supply unit 1 of Embodiment 1 is an example of the specific form of the hot water supply unit of the present invention. In the following description, the front plate 8B side of the frame 8 of the hot water supply unit 1, i.e., the front side of the paper in Figure 1, is defined as the front of the hot water supply unit 1; the left side of the paper in Figure 1 is defined as the left side of the hot water supply unit 1; and the top side of the paper in Figure 1 is defined as the top of the hot water supply unit 1. Furthermore, all directions of front-back, left-right, and up-down shown in the figures below Figure 2 correspond to those in Figure 1. The constituent elements of the hot water supply unit 1 will be described below.

[0042] <Frame> As shown in Figure 1, the hot water supply unit 1 has a frame 8. The frame 8 has a frame body 8A and a front panel 8B.

[0043] As shown in Figure 2, the frame body 8A has a roughly box-shaped structure with an open front opening 8H and a recessed rearward orientation. As shown in Figure 1, the front panel 8B is a roughly rectangular flat plate shape and covers the frame opening 8H. The frame body 8A and the front panel 8B define an interior space that is roughly cuboid in shape. []

[0044] The width direction of the frame 8 is orthogonal to the front-back and vertical directions, and in this embodiment, it is consistent with the left-right direction. The hot water supply unit 1 is usually installed on the pipe axis of the apartment building. Therefore, the size and shape of the frame 8 in the vertical, front-back, and width directions are limited in such a way that it is housed within the pipe axis. []

[0045] 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 frame 8.

[0046] <Combustion fan, first combustion device and second combustion device> As shown in Figures 2 and 3, the hot water supply unit 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.

[0047] The combustion fan 30F is housed in the lower part of the frame 8. The combustion fan 30F supplies combustion air to the first combustion device 31 and the second combustion device 32.

[0048] The first combustion device 31 and the second combustion device 32 are housed in the middle of the frame 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.

[0049] 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 are separated from the combustion chamber 32C and burner 32B by a partition plate 33A as shown in FIG3.

[0050] In Figure 4, the partition plate 33A is omitted. In the first combustion device 31, the flame nozzles 31F of the burner 31B are located within the combustion chamber 31C, and a plurality of them are arranged in the front-back and left-right directions. In the second combustion device 32, the flame nozzles 32F of the burner 32B are located within the combustion chamber 32C, and a plurality of them are arranged in the front-back and left-right directions.

[0051] The height of the flame nozzle 31F of burner 31B is the same as the height of the flame nozzle 32F of burner 32B. In Figure 7, the heights of the flame nozzles 31F and 32F of burners 31B and 32B are shown by height H1.

[0052] As shown in Figure 3, in the first combustion device 31, fuel gas such as municipal gas or liquefied petroleum gas is supplied from a gas supply source (not shown) located outside the frame 8 via a gas supply pipe 30G, an existing gas solenoid valve 30V, a gas proportional valve 30P, a branch pipe 31P, and the first gas solenoid valve 31V to the burner 31B. The burner 31B discharges the fuel gas from the flame nozzle 31F for combustion. In this way, the first combustion device 31 generates combustion exhaust gas, i.e., high-temperature gas.

[0053] In the second combustion device 32, fuel gas is supplied from a gas supply source (not shown) located outside the frame 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 to the burner 32B. The burner 32B then discharges the fuel gas from the flame nozzle 32F for combustion. In this way, the second combustion device 32 generates combustion exhaust gas, i.e., high-temperature gas.

[0054] <First main heat exchanger, first auxiliary heat exchanger, second main heat exchanger, and second auxiliary heat exchanger> As shown in Figures 2 and 3, the hot water supply unit 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.

[0055] 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.

[0056] As shown in Figure 3, 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 hot water supply unit 1 is a bathroom hot water supply unit.

[0057] 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 frame 8.

[0058] 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.

[0059] The first main heat exchanger 41A and the second main heat exchanger 42A share the outer casing 40B shown in Figure 2 and are separated by the partition plate 33B shown in Figure 3.

[0060] 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.

[0061] The first heat exchanger 41B and the second heat exchanger 42B share the tank 40C shown in Figure 2 and are separated by the partition plate 33C shown in Figure 3.

[0062] As shown in Figure 2, the tank body 40C has an exhaust port 49. The exhaust port 49 protrudes forward from the front face of the tank body 40C. As shown in Figure 1, the exhaust port 49 is exposed outside the frame 8 through the exhaust opening 8B1 of the front plate 8B.

[0063] 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 frame 8.

[0064] As shown in Figure 3, the first main heat exchanger 41A has a heat transfer tube 41A1. Although the heat transfer tube 41A1 is simply illustrated in Figure 3, it is serpentine and includes a plurality of straight sections and a plurality of folded sections that turn back into arcs to connect the straight sections. Each straight section of the heat transfer tube 41A1 has a plurality of heat transfer fins.

[0065] 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, so as to absorb the sensible heat of the high-temperature gas.

[0066] The first heat exchanger 41B has a heat transfer tube 41B1. Although the heat transfer tube 41B1 is simply illustrated in Figure 3, the heat transfer tube 41B1 is a serpentine bellows and includes a plurality of straight sections and a plurality of folded sections that are folded back into an arc shape to connect the straight sections.

[0067] 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, in order to absorb the latent heat of the high-temperature gas.

[0068] 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, so as to absorb the sensible heat of the high-temperature gas.

[0069] The second heat exchanger 42B has a heat transfer tube 42B1 with the same structure 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 to absorb the latent heat of the high-temperature gas.

[0070] 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 high-temperature gas and convert it into hot water.

[0071] As shown in Figures 2 and 3, 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 the neutralizer 48. The condensate generated inside the tank 40C is guided to the neutralizer 48 through the drain pipe 48P. After the neutralizer 48 neutralizes the condensate with a neutralizing agent, it discharges the condensate to the outside of the frame 8.

[0072] <Water supply pipes, intermediate water supply pipes, hot water supply pipes and bypass pipes> As shown in Figures 2 to 5, the hot water supply unit 1 includes: 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 a "specific pipe" of the present invention.

[0073] Water supply pipe P1, intermediate water supply pipe P11, hot water supply pipe P2, and bypass pipe P21 are housed within frame 8. Water supply pipe P1, intermediate water supply pipe P11, hot water supply pipe P2, and bypass pipe P21 are located on 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 in the width direction, i.e., the first side, or the right side.

[0074] In addition, the water supply pipe P1, the intermediate water supply pipe P11, the hot water supply pipe P2 and the bypass pipe P21 are located on the right side of the first combustion device 31 and the second combustion device 32 in the width direction.

[0075] 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 flow control unit 50 (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 with multiple bends between the upstream and downstream ends.

[0076] 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.

[0077] The middle section of water supply pipe P1 is connected to the middle section of intermediate water supply pipe P11 via a thin connecting pipe P12.

[0078] The upstream end of the hot water supply pipe P2 is connected to the outlet of the heat transfer pipe 41A1 of the first main heat exchanger 41A. The downstream end of the hot water supply pipe P2 is located slightly below the upstream end. The downstream end of the hot water supply pipe P2 is connected to the hot water supply interface 20H1 of the hot water supply connection component 20 (described later). The hot water supply pipe P2 extends vertically with multiple bends between the upstream and downstream ends. A microbubble generator 9 (described later) is connected midway through the hot water supply pipe P2.

[0079] 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 supply pipe P2.

[0080] <Water supply connection components, hot water supply connection components, water volume control unit and hot water injection control unit> As shown in Figures 2, 3 and 5, the hot water supply unit 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.

[0081] The water supply connection component 10 is located on the right side below the frame body 8A. As shown in Figure 3, the part of the water supply connection component 10 that protrudes downwards from the bottom of the frame body 8A has a connection part that connects the water supply pipe P1 to the water supply path 10S located outside the frame body 8, and a water filter that also serves as a drain plug.

[0082] The part of the water supply connection component 10 that protrudes upward from the bottom of the frame body 8A is connected to the water volume control unit 50.

[0083] As shown in Figure 5, the water flow control unit 50 has a water supply connection port 50H1 that is connected to the upstream end of the water supply pipe P1. That is, the water flow control unit 50 is located between the water supply connection member 10 and the water supply pipe P1. In addition, the water flow control unit 50 has a bypass connection port 50H2 that is connected to the upstream end of the bypass pipe P21.

[0084] As shown in Figure 3, the water volume control unit 50 has a bypass servo mechanism 51 and a water volume servo mechanism 52.

[0085] 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.

[0086] 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.

[0087] As shown in Figures 2, 3, and 5, the hot water supply connection component 20 is located on the right side below the frame body 8A, and is positioned to the right and rear of the water supply connection component 10. As shown in Figure 3, the portion of the hot water supply connection component 20 that protrudes downwards from the bottom of the frame body 8A has a connection part for connecting the hot water supply pipe P2 to the hot water supply path 20S located outside the frame 8, a water hammer buffer valve, and a pressure safety valve that also serves as a drain plug.

[0088] As shown in Figure 5, the portion of the hot water supply connection component 20 that protrudes upward from the lower part of the frame body 8A is T-shaped and bifurcated. The hot water supply connection component 20 has a hot water supply interface 20H1 at the front end of the portion protruding forward from its bifurcation, which is connected to the downstream end of the hot water supply pipe P2.

[0089] The hot water supply connection component 20 is connected to the hot water injection control unit 60 from the upward-protruding part of its fork.

[0090] As shown in Figure 3, 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.

[0091] As shown in Figures 5 and 6, one end of the hot water supply pipe P6 is connected to the hot water inlet 60H1 of the hot water control unit 60. As shown in Figures 3 and 5, the other end of the hot water supply pipe P6 is connected to the bathtub return pipe P3, which will be described later, upstream of the water pump 69.

[0092] 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, the 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, the water supplied to the hot water injection control unit 60 is not supplied to the hot water injection supply pipe P6.

[0093] The atmospheric release valve 63 of the hot water injection control unit 60 and the upstream side of the water volume control unit 50's water volume servo mechanism 52 are connected via a thin connecting pipe P7. Furthermore, the atmospheric release valve 63 and the drain side of the neutralizer 48 are connected via a connecting pipe P8.

[0094] <Bathtub return piping, bathtub return piping and water pump> As shown in Figures 3 and 5, the hot water supply unit 1 includes a bathtub return pipe P3, an intermediate pipe P31, a bathtub forward pipe P4, and a water pump 69.

[0095] The bathtub return pipe P3, intermediate pipe P31, bathtub forward pipe P4, and water pump 69 are housed within the frame 8. The bathtub return pipe P3, intermediate pipe P31, bathtub forward pipe P4, and water pump 69 are located on 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 in the width direction, i.e., the second side, or the left side.

[0096] The upstream end of the bathtub return pipe P3 is connected to the bathtub return connection member 73 located on the left side below the frame body 8A. The bathtub return connection member 73 is connected to the suction port of the bathtub 4 via the external pipe 73A.

[0097] The downstream end of the bathtub return pipe P3 is located above the upstream end of the bathtub return pipe P3. The downstream end of the bathtub return pipe P3 is connected to the inlet of the heat transfer tube 42B1 of the second auxiliary heat exchanger 42B.

[0098] 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.

[0099] 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.

[0100] The middle section of the bathtub return piping P3 and the middle section of the intermediate piping P31 are connected via a thin connecting pipe P32.

[0101] The upstream end of the bathtub return piping P4 is connected to the outlet of the heat transfer pipe 42A1 of the second main heat exchanger 42A. The downstream end of the bathtub return piping P4 is located closer to the bottom than the upstream end of the bathtub return piping P4. The downstream end of the bathtub return piping P4 is connected to the bathtub return connection member 74 located on the left side below the frame body 8A. The bathtub return connection member 74 is connected to the hot water outlet of the bathtub 4 via the external piping 74A.

[0102] Microbubble generator As shown in Figures 2-7, the hot water supply unit 1 further includes a microbubble generator 9. The microbubble generator 9 is connected to the middle of the hot water supply pipe P2 within the frame 8. The microbubble generator 9 is located on 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.

[0103] In addition, 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.

[0104] The microbubble generator 9 is a device that generates microbubbles from 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.

[0105] 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 in the hot water flowing inside. Therefore, the microbubble generator 9 has the following configuration.

[0106] As shown in Figure 8, the microbubble generator 9 has a body 90, an inlet 91, and an outlet 92. The body 90, inlet 91, and outlet 92 are each constructed using different components. In this embodiment, the body 90, inlet 91, and outlet 92 are made of resins that are heat-resistant to high-temperature hot water.

[0107] 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.

[0108] The inflow portion 91 has a fitting portion 91A that engages with the body portion 90, and is connected to the 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.

[0109] The outlet 92 has a fitting part 92A that fits into the body part 90, and is connected to the body part 90 by a plurality of screws 92B. An outlet 92H is formed at the end opposite to the fitting part 92A of the outlet 92, and the outlet 92H is centered on the axis X9.

[0110] The main body 90 contains a venturi tube component 93 and a plurality of stirring components 94. The venturi tube component 93 and each stirring component 94 are made of resin that is heat-resistant to 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.

[0111] A plurality of Venturi flow paths 93A are formed on the Venturi member 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 that is throttled in its middle, a reduced diameter flow path that narrows from the inlet 91 towards the throttling section, and an expanded diameter flow path that widens from the throttling section towards the outlet 92. []

[0112] Each stirring component 94 has a plurality of blades 94A. Each blade 94A is arranged at equal intervals in the circumferential direction of the axis X9 and is inclined to the axis X9.

[0113] The main body 90 uses a Venturi tube member 93 and various stirring members 94 to generate 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 members 94 arranged in series, it is easy to generate bubbles with a diameter of less than 1 μm, and correspondingly, the length L90 of the main body 90 in the axial X9 direction becomes longer.

[0114] The length L90 of the main body 90 in the axial x 9 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 x 9 direction is greater than the outer width (outer diameter). In this embodiment, the length L90 is more than twice the outer diameter D90.

[0115] As shown in Figures 4-7, the microbubble generator 9 is connected to the middle of the hot water supply pipe P2 with its axis X9 inclined. When the microbubble generator 9 is viewed along its width, the inlet 91H is located closer to and above the outlet 92H along the axis X9, and is inclined. In this embodiment, the axis X9 extends approximately parallel to the front-back direction and the up-down direction.

[0116] In this configuration, one side along the X9 axis is located at the rear, and the other side along the X9 axis is located at 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 upwards in the vertical direction.

[0117] The inlet 91H is located on one side of the axis X9, closer to the rear of the main body 90, and is connected to the upstream side P2U of the hot water supply pipe P2. Hot water flows from the upstream side P2U of the hot water supply pipe P2 into the inlet 91H.

[0118] 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 the hot water supply pipe P2. Outlet 92H allows hot water containing microbubbles to flow out towards the downstream side P2D of the hot water supply pipe P2.

[0119] As shown in Figure 4, the upstream side P2U of the hot water supply pipe P2 and the inflow section 91 are fixed by a metal clamp 91C using a one-action mechanism. Similarly, the downstream side P2D of the hot water supply pipe P2 and the outflow section 92 are fixed by a metal clamp 92C using a one-action mechanism.

[0120] Figure 4 shows flame nozzles 31F and 32F, and Figure 7 shows the height of flame nozzles 31F and 32F with height H1. The microbubble generator 9 is located closer to and below the flame nozzles 31F and 32F of the burners 31B and 32B.

[0121] In Figure 7, height H2 shows the height of the downstream hot water supply flow path from the portion connecting the downstream side P2D of the hot water supply pipe P2 to the outlet 92H, up to the hot water supply connection member 20. The outlet 92H is located above the height H2 of the downstream hot water supply flow path.

[0122] In Figure 7, the height of the internal flow path of the water flow control unit 50 is shown as height H3. The microbubble generator 9 is located closer to the top of the water flow control unit 50, and more specifically, closer to the top of the internal flow path of the water flow control unit 50 at height H3.

[0123] <Hot water supply operation> When a user performs an operation to supply hot water, such as opening the hot water outlet valve of a hot water supply terminal located in the kitchen, bathroom, or shower, 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 specific 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 also be set to the bypass open state.

[0124] Water supplied from a source not shown passes through a water supply path 10S, a water supply connection member 10, a water flow control unit 50, a water supply pipe P1, a heat transfer tube 41B1 of the first auxiliary heat exchanger 41B, an intermediate water supply pipe P11, and a heat transfer tube 41A1 of the first main heat exchanger 41A. The water is then heated to hot water by the first auxiliary heat exchanger 41B and the first main heat exchanger 41A. This hot water then passes through a hot water supply pipe P2, where it is fed by a microbubble generator 9, which generates microbubbles with a diameter less than 1 μm.

[0125] Then, 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.

[0126] <Hot water filling action> When the user performs a hot water injection operation, such as pressing the hot water injection 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 according to the situation. The hot water injection solenoid valve 61 then switches to the hot water injection open state. The water pump 69 is in the stopped state.

[0127] Water supplied from a water source not shown flows through water supply pipe P1, becomes hot water in the same way as hot water supply operation, and flows into hot water supply pipe P2. In addition, when the bypass servo mechanism 51 is in the bypass open state, a portion of the water supplied from a water source not shown flows into hot water supply pipe P2 through bypass pipe P21.

[0128] Then, the hot water passes through the hot water supply pipe P2, and along the way, a microbubble generator 9 generates microbubbles containing bubbles with a diameter of less than 1 μm.

[0129] Furthermore, the hot water flows through the hot water supply connection member 20, the hot water injection control unit 60, and the hot water injection supply pipe P6 into the bathtub return pipe P3, upstream of the water pump 69. Then, 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 forward pipe P4, the bathtub forward connection member 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 member 73, and the external pipe 73A. Thus, the hot water, passing through two paths, is stored in the bathtub 4 in a state containing tiny air bubbles.

[0130] <Reheating action> When the user performs a reheating operation, such as pressing the reheat button on a hot water supply remote control located in the kitchen or bathroom, the second combustion device 32 starts to burn and generate high-temperature gas. The hot water injection solenoid valve 61 is then in the hot water injection closed state.

[0131] 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 component 73, bathtub return piping P3, heat transfer pipe 42B1 of the second auxiliary heat exchanger 42B, intermediate piping P31, heat transfer pipe 42A1 of the second main heat exchanger 42A, bathtub forward piping P4, bathtub forward connection component 74, and external piping 74A. As a result, the circulated hot water is reheated by the second auxiliary heat exchanger 42B and the second main heat exchanger 42A.

[0132] <Efficacy and Functions> In the hot water supply unit 1 of Embodiment 1, as shown in Figures 4 and 7, by positioning the microbubble generator 9, housed within the frame 8, closer to and below the flame outlets 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 9 can be reduced. For example, the necessity for constructing the microbubble generator 9 using highly heat-resistant resin or metal can be eliminated. As a result, the hot water supply unit 1 can reduce the material and processing costs of the microbubble generator 9.

[0133] Therefore, the hot water supply unit 1 of Embodiment 1 can suppress the increase in manufacturing costs by housing the microbubble generator 9 within the frame 8.

[0134] Furthermore, in this hot water supply unit 1, as shown in Figures 2-4, the microbubble generator 9 is located on 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 supply pipe P2 in the width direction. Therefore, the hot water supply unit 1 can prevent the piping from becoming excessively long between the hot water supply pipe P2 and the microbubble generator 9, thus allowing for efficient use of the space within the frame 8.

[0135] Furthermore, in this hot water supply unit 1, as shown in Figure 7, the inlet 91H is located closer to and above the outlet 92H. The outlet 92H is located at a height H2 above the downstream hot water supply flow path from the portion connecting the downstream side P2D of the hot water supply pipe P2 to the hot water supply connection member 20. Based on this configuration, the vertical positional relationship is such that the inlet 91H > the outlet 92H ≥ the height H2 of the downstream hot water supply flow path. Therefore, when draining the microbubble generator 9, the hot water supply unit 1 can drain from the hot water supply connection member 20 without the need for a separate drainage circuit.

[0136] Furthermore, in this hot water supply unit 1, the microbubble generator 9 is located above the water flow control unit 50, more specifically, it is located near the height H3 of the internal flow path of the water flow control unit 50. With this configuration, by removing the portion of the hot water supply pipe P2 located downstream of the microbubble generator 9, i.e., the downstream side P2D of the hot water supply pipe P2, it is easy to access or remove the water flow control unit 50. As a result, the maintainability of the hot water supply unit 1 is improved.

[0137] Furthermore, in this hot water supply unit 1, when the microbubble generator 9 is viewed along its width, the axis X9 is inclined such that the inlet 91H is positioned closer to the outlet 92H. Based on this configuration, the microbubble generator 9, which has a relatively long length along the axis X9, can be appropriately positioned below the flame outlets 31F and 32F of the burners 31B and 32B. Moreover, since the microbubble generator 9 is inclined such that the inlet 91H is positioned closer to the outlet 92H, drainage within the microbubble generator 9 can also be easily implemented. As a result, the hot water supply unit 1 achieves improved antifreeze performance.

[0138] Furthermore, in this hot water supply unit 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 supply pipe P2 and the inlet portion 91 forming the inlet 91H is easily observed from the front of the hot water supply unit 1, and the connection is easily accessible through the frame opening 8H. As a result, the maintainability of the hot water supply unit 1 is further improved.

[0139] Furthermore, in this hot water supply unit 1, the outlet 92H is located closer to the front than the inlet 91H. From an assembly workability perspective, the hot water supply interface 20H1, which connects the hot water supply connection member 20 to the downstream end of the hot water supply pipe P2, is more often open towards the front side of the frame 8, and this is also the case in this embodiment. Therefore, by configuring the outlet 92H to be closer to the front than the inlet 91H, the downstream side P2D of the hot water supply pipe P2 connected to the outlet 92H can be smoothly guided to the hot water supply interface 20H1 of the hot water supply connection member 20. As a result, the hot water supply unit 1 achieves improved assembly workability and manufacturability, as well as reduced manufacturing costs.

[0140] Furthermore, in this hot water supply unit 1, as shown in FIG8, the microbubble generator 9 has an inlet section 91, an outlet section 92, and a body section 90, each constructed using different components. Based on this configuration, by pre-preparing multiple types of inlet sections 91 and outlet sections 92 with different shapes, and using the appropriately selected inlet section 91 and outlet section 92, it is possible to easily accommodate vertical inflow and outflow in various connection and installation configurations, such as vertical or inclined installation.

[0141] (Example 2) As shown in Figures 9 and 10, the hot water supply unit 2 of Embodiment 2 uses a water supply pipe P201, a hot water supply pipe P202, and a microbubble generator 209 to replace the water supply pipe P1, the hot water supply pipe P2, and the microbubble generator 9 of the hot water supply unit 1 of Embodiment 1. The water supply pipe P201 is an example of the "specific pipe" of the present invention.

[0142] The other components of Embodiment 2 are the same as those of Embodiment 1. Therefore, the same component numbers are assigned to the same components as in Embodiment 1, and their descriptions are omitted or simplified.

[0143] As shown in Figure 9, in Embodiment 2, the microbubble generator 209 is connected to the water supply pipe P201 within the frame 8. The microbubble generator 209 is located on 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.

[0144] In addition, 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.

[0145] The difference between water supply pipe P201 and water supply pipe P1 in Example 1 is only that the microbubble generator 209 is connected to water supply pipe P201 midway. The other components of water supply pipe P201 are the same as those of water supply pipe P1 in Example 1.

[0146] The difference between hot water supply pipe 202 and hot water supply pipe P2 in Example 1 is that hot water supply pipe 202 extends uninterruptedly from the upstream end to the downstream end. The other components of hot water supply pipe 202 are the same as those of hot water supply pipe P2 in Example 1.

[0147] As shown in Figure 10, the microbubble generator 209 has a body part 290, an inflow part 291, and an outflow part 292, each composed of different components.

[0148] Although the illustrations are omitted, the main body 290 differs from the main body 90 of Embodiment 1 only in that the orientation of the built-in Venturi tube member 93 and each stirring member 94 is opposite to that of Embodiment 1. That is, the Venturi tube member 93 is located on the inflow side 291, and each stirring member 94 is located on the outflow side 292. The other components of the main body 290 are the same as those of the main body 90 of Embodiment 1.

[0149] The inflow section 291 is the same as the outflow section 92 in Embodiment 1. The inflow inlet 291H of the inflow section 291 is the same as the outflow outlet 92H in Embodiment 1.

[0150] 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.

[0151] Similar to Embodiment 1, the main body 290 is centered on the axis X9. However, in Embodiment 2, one side of the axis X9 direction is moved to the front, and the other side of the axis X9 direction is moved to the rear.

[0152] 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.

[0153] The microbubble generator 209 is formed in a generally cylindrical shape (approximately cylindrical) 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 at an angle in the axial X9 direction. When viewed along the width direction, the microbubble generator 209 is angled 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 the front-back and vertical directions.

[0154] 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.

[0155] The inlet 291H is located on one side of the axis X9, closer to the front of 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.

[0156] Outlet 292H is located on the other side of the axis X 209, closer to the rear of 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.

[0157] In Figure 10, the height of the flame nozzles 31F and 32F of burners 31B and 32B is shown as height H1. The microbubble generator 209 is located closer to and below the flame nozzles 31F and 32F of burners 31B and 32B.

[0158] In Figure 10, the height H4 shows the height of the upstream water supply path from the water supply connection member 10 to the portion where the upstream side P201U of the water supply pipe P201 connects with the inlet 291H. The inlet 291H is located above the height H4 of the upstream water supply path.

[0159] In Figure 10, the height of the internal flow path of the water flow control unit 50 is shown as height H3. The microbubble generator 209 is located closer to the top of the water flow control unit 50, and more specifically, it is located above the height H3 of the internal flow path of the water flow control unit 50.

[0160] The hot water supply unit 2 of Embodiment 2 with this configuration is the same as the hot water supply unit 1 of Embodiment 1. Through hot water supply operation and hot water injection operation, it can make hot water containing micro bubbles flow out.

[0161] <Efficacy and Functions> In the hot water supply unit 2 of Embodiment 2, similar to the hot water supply unit 1 of Embodiment 1, by positioning the microbubble generator 209, housed within the frame 8, closer to and below the flame outlets 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 hot water supply unit 2 can reduce the material and processing costs of the microbubble generator 209.

[0162] Therefore, the hot water supply unit 2 of Embodiment 2 can also suppress the increase in manufacturing costs by housing the microbubble generator 209 in the frame 8.

[0163] Furthermore, in this hot water supply unit 2, the microbubble generator 209 is located on 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 hot water supply unit 2 can prevent the piping from becoming excessively long between the water supply pipe P201 and the microbubble generator 209, thus allowing for efficient use of the space within the housing 8.

[0164] Furthermore, in this hot water supply unit 2, the outlet 292H is located closer to and above the inlet 291H. The inlet 291H is located at a height H4 or higher in the upstream water supply path from the water supply connection member 10 to the portion where the upstream side P201U of the water supply pipe P201 connects with the inlet 291H. Based on this configuration, the vertical positional relationship is such that the outlet 292H > the inlet 291H ≥ the height H4 of the upstream water supply path. Therefore, when draining the microbubble generator 209, the hot water supply unit 2 can drain water directly from the water supply connection member 10 without needing to install a separate drainage circuit.

[0165] Furthermore, in this hot water supply unit 2, the microbubble generator 209 is located closer to and above the water flow control unit 50, and more specifically, closer to and above the height H3 of the internal flow path of the water flow control unit 50. With this configuration, by removing the portion of the water supply pipe P201 located upstream 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 maintainability of this hot water supply unit 2 is improved.

[0166] Furthermore, in this hot water supply unit 2, when the microbubble generator 209 is viewed along its width, the axis X9 is inclined such that the outlet 292H is located closer to and above the inlet 291H. With this configuration, the microbubble generator 209, which has a longer length along the axis X9, can be appropriately positioned below the flame outlets 31F and 32F of the burners 31B and 32B. Moreover, since the microbubble generator 209 is inclined with the outlet 292H located closer to and above the inlet 291H, drainage within the microbubble generator 209 can also be easily implemented. As a result, the hot water supply unit 2 achieves improved antifreeze performance.

[0167] Furthermore, in this hot water supply unit 2, the outlet 292H is located closer to the rear than the inlet 291H and opens upwards 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 is easily visible from the front of the hot water supply unit 2, and the connection can be easily reached through the frame opening 8H. As a result, the maintainability of the hot water supply unit 2 is further improved.

[0168] Furthermore, in this hot water supply unit 2, the inlet 291H is located closer to the front than the outlet 292H. From an assembly workability perspective, the water supply connection port 50H1, which connects the water flow control unit 50 to the upstream end of the water supply pipe P201, is more often open towards the front side of the frame 8, and this is also the case in this embodiment. Therefore, by configuring the inlet 291H to be closer to the front than the outlet 292H, the upstream side P201U of the water supply pipe P201 connected to the inlet 291H can be smoothly routed to the water supply connection port 50H1 of the water flow control unit 50. As a result, the hot water supply unit 2 achieves improved assembly workability and manufacturability, as well as reduced manufacturing costs.

[0169] 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. Of course, it can be appropriately modified and applied as long as it does not exceed the scope of its substantive content.

[0170] The present invention also includes a single-function hot water supply unit, which is the configuration after removing the second combustion device 32, 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 forward pipe P4, the water pump 69, etc. from Embodiments 1 and 2.

[0171] In embodiments 1 and 2, although the microbubble generators 9 and 209 are located on the first side (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 closer to and below the flame outlet of the burner, or it can be located on the other side (second side), in front, behind, or below the heat exchanger.

[0172] In embodiments 1 and 2, although the fuel for the first combustion device 31 and the second combustion device 32 is a fuel gas such as municipal 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.

[0173] In Embodiment 1, although the inlet 91H is located further rear 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 of the hot water supply unit 1 in Embodiment 1, the present invention also includes a configuration in which the outlet 92H is located further rear 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 supply pipe P2 and the outlet 92H is easily visible from the front, and the connection can be easily reached through the frame opening 8H, thus further improving maintainability.

[0174] 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 hot water supply 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 is easily visible from the front, and the connection can be easily reached through the frame opening 8H, thus further improving maintainability.

[0175] 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. The water flow control unit can be configured in any way as long as it can control the flow rate of water flowing in the water supply pipe. 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.

[0176] 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.

[0177] 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. (Industrial applicability)

[0178] This invention can be applied, for example, to a hot water supply device that only has a hot water supply function, a hot water supply device 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 hot water and the heating device.

[0179] 1, 2: Hot water supply unit 4: Bathtub 8: Frame 8A: Frame body 8B:Front panel 8B1: Exhaust opening 8B2: External gas inlet opening 8H: Frame opening 9.209: Microbubble generator 10: Water supply connection components 10S: Water Supply Path 20: Hot water supply connection components 20H1: Hot water supply interface 20S: Hot water supply path 30F: Combustion fan 30G: Gas supply pipe 30V: Existing gas solenoid valve 30P: Gas proportional valve 31, 32: Combustion devices (31 First combustion device, 32 Second combustion device) 31B, 32B: Burners 31C, 32C: Combustion chamber 31F, 32F: Flame nozzle of the burner 31P: Branch pipe 31V: First gas solenoid valve 33A, 33B, 33C: Dividers 40B:Outer box 40C: Tank 41A: First main heat exchanger 41B: First heat exchanger 42A: Second main heat exchanger 42B: Second heat exchanger 41A1, 42A1: Heat transfer tubes 41B1, 42B1: Heat transfer tubes 48: Neutralizer 48P: Drain pipe 49: Exhaust port 50: Water Quantity Control Department 50H1: Water supply connection port 50H2: Bypass connection port 51: Bypass Servo Mechanism 52: Water Servo Mechanism 60: Hot water injection control unit 60H1: Hot water inlet 61: Hot water injection solenoid valve 62A, 62B: Check valves 63: Atmospheric opening valve 69: Water pump 73: Bathtub return connection component 73A: External piping 74: Bathtub forward connection components 74A:External piping 90, 290: Ontology part 91, 291: Inflow section 91A, 92A: Fitting part 91B, 92B: Screws 91C: Chuck 91H, 291H: Inlet 92, 292: Outflow part 92C: Chuck 92H, 292H: Outlet 93: Venturi tube components 93A: Venturi tube flow path 94: Mixing components 94A: Blade P1, P201: Water supply pipes P2, P202: Hot water supply pipes P2D, P201D: Downstream side of hot water supply pipe P2U, P201U: Upstream side of hot water supply pipe P3: Bathtub return piping P4: Bathtub back-end piping P6: Hot water supply pipe P7: Narrow connecting tube P8: Connecting pipe P11: Intermediate water supply pipe P12: Thin connecting tube P21: Bypass pipe P31: Intermediate piping P32: Thin connecting tube X9: Axis

Claims

1. A hot water supply device comprising: a frame having a frame body and a front panel; the frame body having a frame opening that is open at the front and a generally box-shaped structure recessed towards the rear; the front panel covering the frame opening; a combustion device housed within the frame and having a combustion chamber and a burner with the flame nozzle located within the combustion chamber to generate high-temperature gas; a heat exchanger housed above the combustion chamber within the frame and heating water passing through it using the high-temperature gas to convert it into hot water; a water supply pipe housed within the frame and located on one side (a first side) of the heat exchanger in a width direction orthogonal to the front-back and vertical directions, extending in the vertical direction and connected to the heat exchanger; and a hot water supply pipe housed within the frame and located on 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 connection component, located below the frame body, is used to connect the water supply pipe to a water supply path located outside the frame body; a hot water supply connection component, located below the frame body, is used to connect the hot water supply pipe to a hot water supply path located outside the frame body; and a water flow control unit, disposed between the water supply connection component and the water supply pipe, is used to control the flow rate of water flowing in the water supply pipe; the hot water supply device is characterized by further comprising: a microbubble generator, connected midway to the hot water supply pipe within the frame body, and formed as a generally cylindrical shape with a length in the axial direction greater than the outer width, and generating microbubbles in the hot water by only hot water flowing inside; the microbubble generator has an inlet and an outlet; the inlet is located on one side in the axial direction, allowing the hot water to flow in from the upstream side of the hot water supply pipe; the outlet is located on the other side in the axial direction, allowing the hot water containing the microbubbles to flow out towards the downstream side of the hot water supply pipe. The inlet and outlet of the microbubble generator are located closer to the bottom than the flame orifice. The microbubble generator is located on the first side of the heat exchanger in the width direction. A portion of the water supply pipe is located closer to the bottom than the flame orifice and directly above the microbubble generator.

2. As in request item 1, the hot water supply unit, wherein, The water control unit has a water supply connection port that opens toward the front side of the frame. The water supply pipe extends forward from the upstream end connected to the water supply connection port, bends, extends upward, bends further backward, extends to a position closer to the bottom of the flame and directly above the microbubble generator, then bends upward and extends to a position closer to the top of the flame.

3. As in request item 1, the hot water supply unit, wherein, The inlet and outlet of the microbubble generator are located closer to and above the water flow control unit.

4. As in request item 3, the hot water supply unit, wherein, One of the aforementioned inlet and outlet is located closer to the rear than the other of the aforementioned inlet and outlet.

5. As in request item 4, the hot water supply unit, wherein, One of the aforementioned inlet and outlet is open in the vertical direction.

6. As in request item 1, the hot water supply unit, wherein, The aforementioned axial direction is inclined relative to the vertical direction.

7. As in request item 6, the hot water supply unit, wherein, At least one of the above-mentioned upstream side of the hot water supply pipe and the above-mentioned microbubble generator, and the above-mentioned microbubble generator and the above-mentioned downstream side of the hot water supply pipe, forms an obtuse angle.

8. As in request item 1, the hot water supply unit, wherein, The aforementioned inlet is located closer to and above the aforementioned outlet, and the aforementioned outlet is located at a height above the downstream hot water supply flow path from the portion of the aforementioned hot water supply pipe connected to the aforementioned outlet to the aforementioned hot water supply connection member.

9. A hot water supply device comprising: a frame having a frame body and a front panel; the frame body having a frame opening that is open at the front and a generally box-shaped structure recessed towards the rear; the front panel covering the frame opening; a combustion device housed within the frame and having a combustion chamber and a burner with the flame nozzle located within the combustion chamber to generate high-temperature gas; a heat exchanger housed above the combustion chamber within the frame and heating water passing through it using the high-temperature gas to convert it into hot water; a water supply pipe housed within the frame and located on one side (a first side) of the heat exchanger in a width direction orthogonal to the front-back and vertical directions, extending in the vertical direction and connected to the heat exchanger; and a hot water supply pipe housed within the frame and located on 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 connection component, located below the frame body, is used to connect the water supply pipe to a water supply path located outside the frame body; a hot water supply connection component, located below the frame body, is used to connect the hot water supply pipe to a hot water supply path located outside the frame body; and a water flow control unit, disposed between the water supply connection component and the water supply pipe, is used to control the flow rate of water flowing in the water supply pipe; the hot water supply device is characterized by further comprising: a microbubble generator, connected to the middle of the water supply pipe within the frame body, and formed into a generally cylindrical shape with a length in the axial direction greater than the outer width, and generating microbubbles in the water by water flowing only inside; the microbubble generator has an inlet and an outlet; the inlet is located on one side in the axial direction, allowing water to flow in from the upstream side of the water supply pipe; the outlet is located on the other side in the axial direction, allowing the water containing the microbubbles to flow out towards the downstream side of the water supply pipe. The inlet and outlet of the microbubble generator are located closer to the bottom than the flame orifice. The microbubble generator is located on the first side of the heat exchanger in the width direction. The axial direction is inclined relative to the vertical direction. A portion of the water supply pipe is located closer to the bottom than the flame orifice and directly above the microbubble generator.

10. As in request item 9, the hot water supply unit, wherein, The outlet is located closer to the rear than the inlet. The water control unit has a water supply connection port that opens toward the front side of the frame. The upstream side of the water supply pipe extends forward from the upstream end connected to the water supply connection port, bends upward, and then bends further backward to connect to the inlet. A portion of the downstream side of the water supply pipe is located closer to the bottom than the flame port and directly above the microbubble generator.

11. As in request item 9, the hot water supply unit, wherein, The aforementioned portion of the aforementioned downstream side of the aforementioned water supply pipe has a portion that extends horizontally.

12. The hot water supply unit as requested in item 11, wherein, The outlet is located closer to the inlet than the inlet. The inlet is located at a height above the upstream water supply path from the water supply connection member to the part where the water supply pipe connects to the inlet.

13. A hot water supply unit as described in any of requests 1 to 12, wherein, The aforementioned microbubble generator is made of resin that is heat-resistant to hot water.

14. A hot water supply unit as described in any of requests 1 to 12, wherein, The aforementioned microbubbles originate from air dissolved in the aforementioned hot water.

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