JP7790722B2 - Bath heater and water heater with bath heater - Google Patents

Description

This disclosure relates to a bath heater and a water heater with a bath heater.

A water flow switch such as that described in Japanese Patent Application Laid-Open No. 2007-323934 (Patent Document 1 below) is known as a water flow switch used in a circulation heating path such as a bath reheating circuit. This water flow switch comprises a casing that forms an internal fluid flow path, a magnetic body disposed within a detection chamber within the casing, a support formed from an elastic member that supports the magnetic body relative to the casing, and a reed switch fixed to the outside of the casing. When a water flow is generated within the detection chamber by a pump circulating hot and cold water, the support elastically bends under the pressure of the flowing water. The bending of the support causes the magnetic body to swing within the detection chamber and approach the reed switch. The reed switch closes as the magnetic body approaches. When the reed switch closes, the control unit detects the generation of a water flow in the reheating circuit and begins heating the hot and cold water.

JP 2007-323934 A

Typically, the water flow switch is intended to be placed directly above the pump. In the configuration of Patent Document 1, the inflow passage that allows hot and cold water to flow into the detection chamber extends vertically, and the inflow direction of hot and cold water from the pump into the inflow passage is the same as the inflow direction of hot and cold water from the inflow passage into the detection chamber. This stabilizes the flow of hot and cold water in the detection chamber.

However, devices such as bath heaters that are equipped with water flow switches have many components. For this reason, depending on the layout of the components within the device, it may not be possible to place the water flow switch directly above the pump, and it may be necessary to place it diagonally above the pump. In such cases, it is possible to provide the flow path from the pump to the detection chamber with a connecting passage that extends horizontally and an inlet passage that extends upward from the end of the connecting passage.

As described above, when a horizontally extending connecting passage is connected to an inlet passage, the inertia of the hot water causes the hot water to flow unevenly in an area of the inlet passage away from the connecting passage, creating a swirling flow downstream of the inlet passage. As a result, the position where the hot water hits the support body is unstable, which can lead to unstable operation of the reed switch.

This disclosure was developed based on the above circumstances, and aims to provide a bath heater that allows the water flow switch to operate stably even if the flow path from the pump to the water flow switch is curved.

The bath heater of the present disclosure is a bath heater installed in a circulation circuit through which hot and cold water circulates, and includes a pump that circulates hot and cold water in the circulation circuit, a water flow switch arranged in the circulation circuit and activated in response to water flow in a first direction, and a connecting pipe connecting the pump and the water flow switch. At the connection between the connecting pipe and the water flow switch, the direction of hot and cold water flow changes from a second direction intersecting the first direction to the first direction. The water flow switch includes a casing that forms the hot and cold water path, a detection piece that is swingably arranged in a detection chamber formed in the casing, and a fixing member that fixes one end of the detection piece. a reed switch fixed to the casing that closes when the detection piece approaches; the casing has an inlet pipe through which hot and cold water flowing in from the connecting pipe flows out into the detection chamber; the inlet pipe has a first cylindrical section, a second cylindrical section located downstream from the first cylindrical section, and a third cylindrical section that connects the first and second cylindrical sections and has a smooth inner surface; the cross-sectional area of the internal space of the second cylindrical section is smaller than the cross-sectional area of the internal space of the first cylindrical section; and the inner surface of the third cylindrical section has a slope located at the back in the second direction and slopes inward toward the third cylindrical section as it moves from upstream to downstream.

This disclosure makes it possible to provide a bath heater in which the water flow switch can operate stably even if the flow path from the pump to the water flow switch is curved.

FIG. 1 is a schematic circuit diagram of a water heater with a bath heater according to a first embodiment. FIG. 2 is a perspective view of the pump, the water flow switch, and the connecting pipe portion. FIG. 3 is a plan view of the pump, the water flow switch, and the connecting pipe section. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a cross-sectional view taken along line BB in FIG. FIG. 6 is a cross-sectional view taken along the line CC in FIG. FIG. 7 is a perspective view of the cross section DD in FIG. 6 as seen from below. Figure 8 is a cross-sectional view showing cross sections of the inlet pipe section cut at different height positions. Figure 8(A) is a cross-sectional view taken along line D-D in Figure 6. Figure 8(B) is a cross-sectional view taken along line E-E in Figure 6. Figure 8(C) is a cross-sectional view taken along line F-F in Figure 6. Figure 8(D) is a cross-sectional view taken along line G-G in Figure 6. FIG. 9 is a perspective view of a casing body according to the second embodiment. FIG. 10 is a cross-sectional perspective view showing a partition wall provided in the inlet pipe portion.

Description of the embodiments of the present disclosure
First, embodiments of the present disclosure will be listed and described.

(1) The bath heater of the present disclosure is a bath heater installed in a circulation circuit through which hot and cold water circulates, and includes a pump that circulates hot and cold water in the circulation circuit, a water flow switch arranged in the circulation circuit and activated in response to water flow in a first direction, and a connecting pipe connecting the pump and the water flow switch. At the connection between the connecting pipe and the water flow switch, the direction of hot and cold water flow changes from a second direction intersecting the first direction to the first direction. The water flow switch includes a casing that forms a path for hot and cold water, a detection piece that is swingably arranged within a detection chamber formed in the casing, and a fixing member that fixes one end of the detection piece. and a reed switch fixed to the casing that closes when the detection piece approaches. The casing has an inlet pipe through which hot and cold water flowing in from the connecting pipe flows out into the detection chamber. The inlet pipe has a first cylindrical section, a second cylindrical section located downstream from the first cylindrical section, and a third cylindrical section that connects the first and second cylindrical sections and has a smooth inner surface. The cross-sectional area of the internal space of the second cylindrical section is smaller than the cross-sectional area of the internal space of the first cylindrical section. The inner surface of the third cylindrical section has a slope located at the back in the second direction and slopes inward toward the third cylindrical section as it moves from upstream to downstream.

In the above configuration, hot water flows from the pump through the connecting pipe into the inlet pipe of the water flow switch. At the connection between the connecting pipe and the water flow switch, the flow direction of the hot water is shifted from the second direction to the first direction. As a result, a swirling flow of hot water is generated at the connection between the connecting pipe and the water flow switch. The hot water that flows from the connecting pipe into the inlet pipe is shifted toward the back in the second direction and flows in the first direction within the first cylindrical portion of the inlet pipe.

The third cylindrical portion connected to the first cylindrical portion has an inner peripheral surface provided with an inclined portion that is disposed on the rear side in the second direction and slopes inwardly of the third cylindrical portion. The cross-sectional area of the internal space of the second cylindrical portion is smaller than the cross-sectional area of the internal space of the first cylindrical portion. Therefore, the flow of hot and cold water is easily rectified by passing through the interiors of the third cylindrical portion and the second cylindrical portion.
This stabilizes the flow of hot and cold water in the detection chamber, allowing the hot and cold water pressure to be concentrated at a fixed position on the detection piece, resulting in stable operation of the water flow switch.

(2) The casing preferably includes an outlet pipe section through which hot and cold water flows out from the detection chamber in a third direction perpendicular to the first direction, the fixing member is arranged on the opposite side of the second cylindrical section from the third direction, the end of the detection piece opposite the fixing member is arranged facing the internal space of the second cylindrical section, and the internal space of the second cylindrical section is preferably flatter in the third direction than the internal space of the first cylindrical section.

In the above configuration, the end of the detection piece opposite the fixed member side is positioned facing the internal space of the second cylindrical portion, allowing hot and cold water to be guided from the second cylindrical portion toward the tip of the detection piece. This prevents hot and cold water from concentrating on the fixed member side of the detection piece, which would cause the detection piece to stop swinging, stabilizing the operation of the water flow switch.

(3) It is preferable that the second cylindrical portion is provided with a partition wall extending in the third direction that divides the internal space of the second cylindrical portion in directions perpendicular to both the third direction and the first direction.

In the above configuration, the partition wall suppresses the swirling flow of hot and cold water, further enhancing the effect of straightening the hot and cold water flow.
Furthermore, since the partition wall extends in the third direction, which is the direction in which the second cylindrical portion is flat, it is easy to ensure the cross-sectional area of the internal space of the second cylindrical portion even when the partition wall is installed, and pressure loss of hot water flowing through the second cylindrical portion is less likely to occur.

(4) The water heater with a bath heater of the present disclosure is a water heater with a bath heater that includes the above-mentioned bath heater, a hot water supply circuit, and a burner that heats a bath heat exchanger provided in the circulation circuit and a hot water heat exchanger provided in the hot water supply circuit.

[Details of the embodiment of the present disclosure]
The present disclosure will be described below with reference to exemplary embodiments. The present disclosure is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims.

<Embodiment 1>
A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. FIG.

[Overall structure of a water heater with a bath boiler]
FIG. 1 is a schematic circuit diagram of a water heater with a bath heater 1 including a bath heater 1A.
The bath heater-equipped water heater 1 has an inner body 2 housed in a housing (not shown) and includes a hot water combustion chamber 4 and a bath combustion chamber 5 separated by a partition member 3, and a burner 6. The burner 6 includes hot water burners 6A, 6A... disposed below the hot water combustion chamber 4 and a bath burner 6B disposed below the bath combustion chamber 5. Each combustion chamber 4, 5 is provided with an ignition plug 8 and a flame rod 9. A combustion fan 10 is provided below the inner body 2 to supply combustion air to each burner 6A, 6B.

A hot water primary heat exchanger 11 and a hot water secondary heat exchanger 12 (an example of a hot water heat exchanger) are provided at the top of the hot water combustion chamber 4, through which the combustion exhaust from the hot water burner 6A passes. A bath primary heat exchanger 13 and a bath secondary heat exchanger 14 (an example of a bath heat exchanger) are provided at the top of the bath combustion chamber 5, through which the combustion exhaust from the bath burner 6B passes. Each secondary heat exchanger 12, 14 is housed in an exhaust hood 15 provided at the top of the inner body 2. The exhaust hood 15 has an exhaust port 16 formed therein, which discharges the combustion exhaust that has passed through each secondary heat exchanger 12, 14.

A gas pipe 17, which is connected to an external gas pipe, is connected to a gas inlet on the bottom of the housing. Branch gas pipes 18, 18... branching off from the gas pipe 17 are connected to each hot water burner 6A and bath burner 6B, and each branch gas pipe 18 is equipped with a gas solenoid valve 19 that opens and closes the gas flow path. Furthermore, a main gas solenoid valve 20 and a gas proportional valve 21 are installed upstream of the gas pipe 17 before it branches.

A water supply pipe 22, which is connected to a water inlet on the bottom of the housing, is connected to the inlet of the heat absorption pipe of the hot water secondary heat exchanger 12. From upstream, the water supply pipe 22 is provided with a strainer 23 equipped with a drain plug, a hot water supply water volume sensor 24 that detects the volume of water flowing through the water supply pipe 22, a hot water supply water inlet thermistor 25 that detects the inlet water temperature, and a water volume control motor 26. The outlet of the heat absorption pipe is connected to the inlet of the heat transfer pipe of the hot water supply primary heat exchanger 11, and the outlet of the heat transfer pipe is connected to a hot water outlet pipe 27 that is connected to a hot water outlet on the bottom of the housing. The hot water outlet pipe 27 is provided with a hot water heat exchanger thermistor 28 that detects the outlet temperature from the hot water primary heat exchanger 11, and a hot water outlet thermistor 29 that detects the outlet hot water temperature from the appliance downstream of the hot water heat exchanger thermistor 28. A bypass pipe 30 that bypasses the hot water primary and secondary heat exchangers 11, 12 is connected between the upstream side of the hot water outlet thermistor 29 in the hot water outlet pipe 27 and the downstream side of the water volume control motor 26 in the water supply pipe 22, and a water distribution valve 31 that controls the bypass flow rate is provided in the bypass pipe 30.
In this way, a hot water circuit A is formed within the housing, in which water from the water supply pipe 22 passes through the hot water secondary heat exchanger 12 and the hot water primary heat exchanger 11 in that order, is heated by heat exchange with the combustion exhaust of the hot water burner 6A, and then is discharged from the hot water outlet pipe 27.

On the other hand, a return pipe 35 connected to the bath return port on the bottom of the housing is connected to the inlet of the heat absorption pipe of the bath secondary heat exchanger 14. The bath return port is connected to the bathtub 37 via an external return pipe 36. A pump 38 is provided downstream of the return pipe 35. A bath return thermistor 39 that detects the bath return temperature is provided upstream of the pump 38. A water flow switch 40 and a water level sensor 41 are provided downstream of the pump 38. The water flow switch 40 detects the flow of hot and cold water sent out from the pump 38 and activates the bath burner 6B. The detailed configuration of the water flow switch 40 will be described later.
The outlet of the heat absorption pipe of the bath secondary heat exchanger 14 is connected to the inlet of the heat transfer pipe of the bath primary heat exchanger 13. The outlet of the heat transfer pipe is connected to an inlet pipe 42 connected to the bath inlet on the bottom of the housing. The bath inlet is connected to the bathtub 37 via an external inlet pipe 43. The inlet pipe 42 is equipped with a bath inlet thermistor 44 that detects the bath inlet temperature.

In this way, within the housing, when the pump 38 is operated, hot water from the bathtub 37 passes through the return pipe 35, the bath secondary heat exchanger 14, and the bath primary heat exchanger 13 in that order, where it is heated by heat exchange with the combustion exhaust from the bath burner 6B, and then returns to the bathtub 37 through the supply pipe 42, forming a bath circuit B (an example of a circulation circuit).

In this disclosure, the bath heater 1A includes a hot water circulation path in the bath circuit B, from the return pipe 35 connected to the bath return port on the bottom of the housing to the supply pipe 42 connected to the bath supply port on the bottom of the housing. The bath heater 1A is connected to the bathtub 37 through external piping (external return pipe 36 and external supply port 43). In other words, the bath circuit B, together with the external piping, forms a circulation circuit connecting the bathtub 37 and the bath heater 1A.

A drop pipe 45 is connected between the outlet pipe 27 downstream of the bypass pipe 30 and the return pipe 35 upstream of the pump 38. This drop pipe 45 is provided with a drop water solenoid valve 46, which opens and closes the drop pipe 45, and a bath water volume sensor 47, which detects the amount of water flowing through the drop pipe 45, from the upstream side (the outlet pipe 27 side). Three check valves 48, 48, 48 are provided downstream of the bath water volume sensor 47. A cut-off valve 49 is connected between these check valves 48. This cut-off valve 49 is connected to a drain pipe 50 connected to an overflow port provided on the bottom of the housing and an inlet pipe 51 connected to the downstream side of the strainer 23 in the water supply pipe 22. When the internal pressure of the hot water in the drop pipe 45 increases due to the back pressure from the return pipe 35 and becomes greater than the back pressure from the inlet pipe 51, the cut-off valve 49 discharges the hot water that has flowed back from the drop pipe 45 through the drain pipe 50 to the overflow port.

A neutralizer 55 is provided within the housing to neutralize the drain generated in the hot water secondary heat exchanger 12 and the bath secondary heat exchanger 14. This neutralizer 55 is connected to a drain receiver 56 provided on the bottom of the exhaust hood 15 via a drain inlet pipe 57, and is connected to the drain pipe 50 of the isolation valve 49 via a drain outlet pipe 58. The neutralizer 55 is also provided with a water level electrode 59 for detecting the water level, and a drain outlet 60 for discharging the drain from the bottom of the housing.

Although not shown, the bath water heater 1 is equipped with a controller that receives detection signals from thermistors, sensors, etc. and operates various valves to control the outlet water temperature and fill the bathtub 37 with water, as well as a remote control that is connected to the controller so that it can communicate with the controller.

[Water flow switch, connecting pipe]
As shown in Figure 2, the water flow switch 40 of this embodiment is connected to the discharge port 38B of the pump 38 via a connecting pipe 70. The suction port 38A of the pump 38 is connected to the bath return port. A pipe 78 is connected downstream of the water flow switch 40.
As shown in Figure 5, the connecting pipe 70 includes a first bent pipe 70A connected to the discharge port 38B of the pump 38, a straight pipe 70B extending horizontally from the first bent pipe 70A, and a second bent pipe 70C connecting the straight pipe 70B to the water flow switch 40. Each bent pipe 70A, 70C has a bent shape, with openings at both ends extending substantially vertically. At the connection between the connecting pipe 70 and the water flow switch 40 (the second bent pipe 70C in this embodiment), the flow direction of hot and cold water changes from the right in Figure 5 (an example of the second direction) to upward (an example of the first direction).

As shown in Figure 4, the water flow switch 40 comprises a casing 71 through which hot and cold water flows, a detection piece 72 arranged within the casing 71, a fixing member 73 that fixes the rear end of the detection piece 72, and a reed switch 74 fixed to the casing 71.

The casing 71 is made of synthetic resin. The casing 71 includes a box-shaped casing body 71A and a lid 71B that closes the upper opening of the casing body 71A. A detection chamber 75 for detecting water flow is formed inside the casing 71. A fixing member 73 is formed to protrude downward from the underside of the lid 71B. The fixing member 73 is disposed at a rear position within the detection chamber 75. The reed switch 74 is fixed to a front position on the upper surface of the lid 71B.
The casing body 71A includes an inlet pipe 76 that penetrates the bottom wall of the casing body 71A in the vertical direction, and an outlet pipe 77 that penetrates the front wall of the casing body 71A in the front-to-rear direction. The upper part of the inlet pipe 76 protrudes above the bottom wall of the casing body 71A. The upper end of the inlet pipe 76 is inclined downward toward the front. The outlet pipe 77 extends forward and is connected to the inlet of the bath secondary heat exchanger 14 via piping 78.

The detection piece 72 comprises an elastically deformable elastic piece 72A and a magnetic body 72B fixed to the front end of the elastic piece 72A. The rear end of the elastic piece 72A is fixed to a fixed member 73. The front portion of the elastic piece 72A is arranged facing the internal space of the inlet pipe portion 76 (second cylindrical portion 76B) so as to block the upper part of the second cylindrical portion 76B. When hot water flows into the detection chamber 75 from the inlet pipe portion 76, the pressure from the hot water causes the elastic piece 72A to elastically deform, with its rear end fixed to the fixed member 73 as its base end. As a result, the front end of the elastic piece 72A moves upward, away from the inlet pipe portion 76. This brings the magnetic body 72B closer to the reed switch 74, switching the reed switch 74 from an open state to a closed state.

[Inflow pipe section, first cylindrical section, second cylindrical section]
As shown in FIGS. 4 to 6 , the inlet pipe 76 includes a first cylindrical portion 76A, a second cylindrical portion 76B disposed downstream of the first cylindrical portion 76A, and a third cylindrical portion 76C connecting the first cylindrical portion 76A and the second cylindrical portion 76B. As shown in FIGS. 7 and 8A, the first cylindrical portion 76A is cylindrical. As shown in FIG. 8D, the second cylindrical portion 76B is cylindrical, with the rear portion of the internal space of the first cylindrical portion 76A eliminated. Specifically, the rear side of the inner circumferential surface of the second cylindrical portion 76B is provided with an orthogonal surface 80 perpendicular to the axis extending in the front-rear direction. When the inlet pipe 76 is cut horizontally, the cross-sectional area of the internal space of the second cylindrical portion 76B is smaller than the cross-sectional area of the internal space of the first cylindrical portion 76A (see FIGS. 8A and 8D). The internal space of the second cylindrical portion 76B is flatter in the front-rear direction than the internal space of the first cylindrical portion 76A.

[Third cylindrical part, inclined part]
As shown in Fig. 6, the third cylindrical portion 76C has a smooth inner circumferential surface that continuously connects the first cylindrical portion 76A and the second cylindrical portion 76B. As shown in Figs. 8A to 8C, the inner circumferential surface of the third cylindrical portion 76C is provided with an inclined portion 81 disposed on the rear side in the second direction. Here, the second direction refers to the flow direction of hot water before it changes direction upward at the connection portion between the connecting pipe portion 70 and the inlet pipe portion 76, and corresponds to the right side in Fig. 5. The inclined portion 81 is inclined inward of the third cylindrical portion 76C as it moves from upstream to downstream (from bottom to top).
The inner surface of the third cylindrical portion 76C, excluding the inclined portion 81, is a cylindrical inner surface that is continuously connected to the cylindrical inner surfaces of the first cylindrical portion 76A and the second cylindrical portion 76B.

In this embodiment, the flow direction of hot water is changed from the second direction to upward at the connection portion (second bent pipe portion 70C) between the connecting pipe portion 70 and the inlet pipe portion 76. At this time, the hot water collides with the inner surface of the second bent pipe portion 70C (and the first tubular portion 76A) at the rear in the second direction, forming a swirling flow and being pushed out by the following hot water. As a result, the hot water introduced into the inlet pipe portion 76 tends to rise while swirling. The swirling flow here refers to a circular flow that follows the inner surface of the first tubular portion 76A. Furthermore, when the hot water is deflected upward from the second direction and enters the inlet pipe portion 76, the inertia of the hot water makes it more likely that the hot water will be biased toward the rear side of the inlet pipe portion 76 in the second direction rather than the front side.

However, in this embodiment, an inclined portion 81 is formed at the rear side in the second direction of the inner surface of the third tubular portion 76C, which slopes inward as it moves from upstream to downstream (as it moves upward).Therefore, the hot water that is on an upward trend rises while encountering resistance from this inclined portion 81, and the swirling component of the hot water is gradually suppressed.
Furthermore, since the inclined portion 81 is disposed on the inner circumferential surface of the third cylindrical portion 76C at the rear in the second direction, the bias of the hot water toward the rear in the second direction is alleviated as the hot water flows upward (downstream). Therefore, according to this embodiment, even if the connection portion between the connecting pipe portion 70 and the inlet pipe portion 76 is bent, the flow of hot water flowing into the detection chamber 75 can be stabilized, and the water flow switch 40 can be stably operated.

As shown in FIG. 8(B), the upstream end (lower end) of the inclined portion 81 has an upstream end surface 81A that is substantially perpendicular to the axis extending in the second direction. The upstream end surface 81A is formed facing the opposite side of the second direction. As shown in FIG. 7, the upstream end surface 81A narrows toward the upstream side (lower side) and disappears into a dot at the boundary between the third tubular portion 76C and the first tubular portion 76A. As shown in FIG. 4, the downstream end (upper end) of the inclined portion 81 is substantially perpendicular to the axis extending in the front-to-rear direction and smoothly connects to the perpendicular surface 80 of the second tubular portion 76B. The downstream end of the inclined portion 81 is formed facing forward. As shown in FIGS. 8(B) and 8(C), the inclined portion 81 is formed inward of the third tubular portion 76C so that the facing direction of the inclined portion 81 continuously changes from the direction opposite to the second direction to the forward direction from the upstream end surface 81A to the downstream end. In this embodiment, the normal vector of the inclined portion 81 changes by approximately 30° in plan view (when viewed from the first direction) from the upstream end face 81A to the downstream end. It is preferable that this change in angle of the normal vector of the inclined portion 81 in plan view be an acute angle.

As shown in Figure 3, hot water flows into the water flow switch 40 in the second direction (diagonally rearward to the left) through the connecting pipe 70 and flows out forward toward the pipe 78. In other words, the flow direction of hot water upstream and downstream of the water flow switch 40 is offset by a finite angle in the horizontal plane. This can cause pressure loss and swirling flow of hot water inside the water flow switch 40.
In this embodiment, the inclined portion 81 has a smooth inner surface, and the facing direction of the inclined portion 81 continuously changes from the direction opposite the second direction to the forward direction, thereby minimizing the pressure loss of hot water inside the water flow switch 40 and making it easier to straighten the hot water.

[Effects of the First Embodiment]
As described above, the bath heater 1A according to the first embodiment is a bath heater 1A that is installed in a circulation circuit (bath circuit B) through which hot and cold water circulates, and includes a pump 38 that circulates hot and cold water in the circulation circuit, a water flow switch 40 that is arranged in the circulation circuit and operates in response to water flow in a first direction (upward), and a connecting pipe 70 that connects the pump 38 and the water flow switch 40. At the connection between the connecting pipe 70 and the water flow switch 40, the flow direction of the hot and cold water changes from a second direction that intersects with the first direction to the first direction. The water flow switch 40 includes a casing 71 that forms a path for the hot and cold water, a detection piece 72 that is swingably arranged in a detection chamber 75 formed in the casing 71, and a fixing member that fixes one end of the detection piece 72. This bath heater (1A) comprises a member (73) and a reed switch (74) fixed to a casing (71) that closes when a detection piece (72) approaches. The casing (71) has an inlet pipe section (76) through which hot and cold water flowing in from a connecting pipe section (70) flows out into a detection chamber (75). The inlet pipe section (76) comprises a first cylindrical section (76A), a second cylindrical section (76B) arranged downstream from the first cylindrical section (76A), and a third cylindrical section (76C) that connects the first cylindrical section (76A) and the second cylindrical section (76B) and has a smooth inner surface. The cross-sectional area of the internal space of the second cylindrical section (76B) is smaller than the cross-sectional area of the internal space of the first cylindrical section (76A). The inner surface of the third cylindrical section (76C) has an inclined section (81) that is arranged at the back in the second direction and inclined inward of the third cylindrical section (76C) as it moves from upstream to downstream.

In the above configuration, hot water flows from the pump 38 through the connecting pipe 70 into the inlet pipe 76 of the water flow switch 40. At the connection between the connecting pipe 70 and the water flow switch 40, the flow direction of the hot water is shifted from the second direction to the first direction. Therefore, a swirling flow of hot water is generated at the connection between the connecting pipe 70 and the water flow switch 40. The hot water that flows from the connecting pipe 70 into the inlet pipe 76 flows in the first direction within the first cylindrical portion 76A of the inlet pipe 76, shifting toward the back side in the second direction.

The inner circumferential surface of the third cylindrical portion 76C connected to the first cylindrical portion 76A is provided with an inclined portion 81 that is disposed on the rear side in the second direction and inclined inward of the third cylindrical portion 76C. The cross-sectional area of the internal space of the second cylindrical portion 76B is smaller than the cross-sectional area of the internal space of the first cylindrical portion 76A. Therefore, the flow of hot and cold water is easily rectified by passing through the interiors of the third cylindrical portion 76C and the second cylindrical portion 76B.
This stabilizes the flow of hot and cold water in the detection chamber 75, allowing the hot and cold water to be pressurized in a concentrated manner at a fixed position on the detection piece 72. As a result, the water flow switch 40 can be operated stably.

In embodiment 1, the casing 71 includes an outlet pipe section 77 through which hot and cold water flows out from the detection chamber 75 in a third direction (forward) perpendicular to the first direction, the fixing member 73 is arranged on the opposite side of the third direction (rearward) from the second cylindrical section 76B, the end of the detection piece 72 opposite the fixing member 73 side is arranged opposite the internal space of the second cylindrical section 76B, and the internal space of the second cylindrical section 76B is flatter in the third direction than the internal space of the first cylindrical section 76A.

In the above configuration, the end of the detection piece 72 opposite the fixed member 73 is positioned facing the internal space of the second tubular portion 76B, allowing hot and cold water to be guided from the second tubular portion 76B toward the tip of the detection piece 72. This prevents hot and cold water from concentrating on the fixed member 73 side of the detection piece 72, which would cause the detection piece 72 to stop swinging, thereby stabilizing the operation of the water flow switch 40.

The water heater with bath heater 1 according to the first embodiment is a water heater with bath heater 1 that includes a bath heater 1A, a water heater circuit A, and a burner 6 that heats the bath heat exchangers (bath primary and secondary heat exchangers 13 and 14) provided in the circulation circuit (bath circuit B) and the water heater heat exchangers (water heater primary and secondary heat exchangers 11 and 12) provided in the water heater circuit A.

<Embodiment 2>
A second embodiment of the present disclosure will be described with reference to Figures 9 and 10. In the second embodiment, the configuration other than the inlet pipe portion 176 of the casing 171 is the same as that of the first embodiment, and therefore the same reference numerals as those in the first embodiment will be used and the description thereof will be omitted in some cases.

Fig. 9 is a perspective view of a casing body 171A of a casing 171 according to the second embodiment. Fig. 10 is a cross-sectional perspective view of the casing body 171A. As in the first embodiment, an outlet pipe 77 is formed on the front wall of the casing body 171A, opening forward (an example of a third direction). Hot water that flows into the detection chamber 75 from the inlet pipe 176 flows through the outlet pipe 77 and flows out forward.
As shown in FIG. 10, the inflow pipe portion 176 has a first cylindrical portion 76A, a second cylindrical portion 76B, and a third cylindrical portion 76C, similar to the first embodiment.

[Partition wall]
In the second embodiment, the inflow pipe 176 further includes a partition wall 190 that divides the interior space of the inflow pipe 176 in the left-right direction (an example of a direction perpendicular to both the third direction and the first direction). The partition wall 190 extends in the front-rear direction and connects the front inner wall surface and the rear inner wall surface of the inflow pipe 176. In this embodiment, the partition wall 190 is provided across the entire inflow pipe 176 in the up-down direction.

[Effects of Embodiment 2]

In embodiment 2, the second cylindrical portion 76B is provided with a partition wall 190 that extends in the third direction and divides the internal space of the second cylindrical portion 76B in a direction (left-right direction) perpendicular to both the third direction and the first direction.

In the above configuration, the partition wall 190 can suppress the swirling flow of hot and cold water, further enhancing the effect of straightening the hot and cold water flow.
Furthermore, since the partition wall 190 extends in the third direction, which is the direction in which the second cylindrical portion 76B is flat, even when the partition wall 190 is provided, it is easy to ensure the cross-sectional area of the internal space of the second cylindrical portion 76B, and pressure loss of hot water flowing through the second cylindrical portion 76B is less likely to occur.

<Other Embodiments>
(1) In the first embodiment, the water heater 1 with the bath heater 1A is illustrated as an example, but the bath heater may not be provided in conjunction with the hot water supply circuit.

(2) In embodiment 1, the connection between the connecting pipe 70 and the inlet pipe 76, where the hot water changes direction from the second direction to the first direction, was the second bend 70B of the connecting pipe 70. However, this connection where the hot water changes direction from the second direction to the first direction may be provided on the inlet pipe. For example, the inlet pipe may be cylindrical with a bottom, and the connecting pipe may be inserted into a through hole provided in the side wall of the inlet pipe.

(3) In embodiment 1, the connecting pipe section 70 includes a straight pipe section 70B extending horizontally and first and second bent pipe sections 70A and 70C. However, the connecting pipe section may have a shape that extends in a direction intersecting the first direction at the end on the inlet pipe section side. For example, the straight pipe section of the connecting pipe section may be slightly inclined with respect to the horizontal direction. The connecting pipe section may also be curved.

(4) In the second embodiment, the partition wall 190 was provided over the entire area of the inlet pipe section 176 in the extension direction (vertical direction), but the partition wall need only be provided on at least the second cylindrical section. Increasing the length of the partition wall relative to the inlet pipe section makes it easier to suppress the swirling flow of hot water, but increases the pressure loss of the hot water. Therefore, the length and placement of the partition wall can be changed as appropriate.

1: Water heater with bath heater, 1A: Bath heater, 2: Inner body, 3: Partition member, 4: Water heater combustion chamber, 5: Bath combustion chamber, 6: Burner, 6A: Water heater burner, 6B: Bath burner, 8: Ignition plug, 9: Flame rod, 10: Combustion fan, 11: Water heater primary heat exchanger, 12: Water heater secondary heat exchanger, 13: Bath primary heat exchanger, 14: Bath secondary heat exchanger, 15: Exhaust hood, 16: Exhaust port, 17: Gas pipe, 18: Gas branch pipe, 19: Gas solenoid valve, 20: Main gas solenoid valve, 21: Gas proportional valve, 22: Water supply pipe, 23: Strainer, 24: Water supply volume sensor, 25: Water supply inlet thermistor, 26: Water volume control motor, 27: Water outlet pipe, 28 : Hot water heat exchanger thermistor, 29: Hot water outlet thermistor, 30: Bypass pipe, 31: Water distribution valve, 35: Return pipe, 36: External return pipe, 37: Bathtub, 38: Pump, 39: Bath return thermistor, 40: Water flow switch, 41: Water level sensor, 42: Supply pipe, 43: External supply pipe, 44: Bath supply thermistor, 45: Drop pipe, 46: Drop water solenoid valve, 47: Bath water level sensor, 48: Check valve, 49: Cut-off valve, 50: Drain pipe, 51: Inlet pipe, 55: Neutralizer, 56: Drain receiver, 57: Drain inlet pipe, 58: Drain outlet pipe, 59: Water level electrode, 60: Drain outlet 70: connecting pipe section, 70A: first bent pipe section, 70B: straight pipe section, 70C: second bent pipe section 71, 171: casing, 71A, 171A: casing body, 71B: lid body, 72: detection piece, 72A: elastic piece, 72B: magnetic material, 73: fixing member, 74: reed switch, 75: detection chamber 76, 176: inlet pipe section, 76A: first cylindrical section, 76B: second cylindrical section, 76C: third cylindrical section, 77: outlet pipe section, 78: piping, 80: orthogonal surface, 81: inclined section, 81A: upstream end surface, 190: partition wall A: hot water supply circuit, B: bath circuit (circulation circuit)

Claims (4)

A bath heater configured to include a part of a circulation circuit through which hot water circulates,
a pump that circulates hot and cold water through the circulation circuit;
a water flow switch disposed in the circulation circuit and operable in response to a water flow in a first direction;
a connecting pipe portion that connects the pump and the water flow switch,
At a connection portion between the connecting pipe portion and the water flow switch, the flow direction of hot and cold water changes from a second direction intersecting the first direction to the first direction,
The water flow switch comprises a casing that forms a path for hot and cold water, a detection piece that is swingably provided in a detection chamber formed in the casing, a fixing member that fixes one end of the detection piece, and a reed switch that is fixed to the casing and is closed when the detection piece approaches.
The casing includes an inlet pipe portion through which hot and cold water flowing in from the connecting pipe portion flows out into the detection chamber,
The inlet pipe portion is
A first cylindrical portion;
a second cylindrical portion disposed downstream of the first cylindrical portion;
a third cylindrical portion that connects the first cylindrical portion and the second cylindrical portion and has a smooth inner circumferential surface,
a cross-sectional area of the internal space of the second cylindrical portion is smaller than a cross-sectional area of the internal space of the first cylindrical portion;
an inclined portion inclined inwardly of the third cylindrical portion from upstream to downstream in the second direction is provided on an inner circumferential surface of the third cylindrical portion ;
A bath heater , wherein a vertical surface extending in the first direction is provided on the inner circumferential surface of the third cylindrical portion on the front side in the second direction . The casing includes an outflow pipe portion through which hot and cold water flows out from the detection chamber in a third direction perpendicular to the first direction,
the fixing member is disposed on the opposite side of the second cylindrical portion in the third direction,
the detection piece includes an elastic piece that is elastically deformable and a magnetic body, and one end of the elastic piece is fixed to the fixing member;
a portion of the elastic piece to which the magnetic body is attached is disposed opposite to the internal space of the second cylindrical portion;
The bath heater according to claim 1, wherein the internal space of the second cylindrical portion is flatter in the third direction than the internal space of the first cylindrical portion. The bath heater according to claim 2, wherein the second cylindrical portion is provided with a partition wall extending in the third direction that divides the internal space of the second cylindrical portion in directions perpendicular to both the third direction and the first direction. A bath heater according to any one of claims 1 to 3,
A hot water circuit;
A water heater with a bath heater, comprising: a burner for heating a bath heat exchanger provided in the circulation circuit and a hot water heat exchanger provided in the hot water circuit.