JP7828666B2 - Drain discharge method, discharge device, and hot water supply device - Google Patents

Description

This invention relates, for example, to a technology for discharging condensate generated in a heat exchanger when the heat of combustion of fuel gas is exchanged for feedwater or the like.

When the heat of combustion from fuel gas is exchanged for water supply, condensate is generated in the heat exchanger. However, in high-efficiency hot water supply systems equipped with a secondary heat exchanger that recovers the latent heat of combustion, condensate generation is particularly pronounced. This condensate is neutralized in a neutralizer, then collected in a drain tank, and discharged through the bathtub when the bathtub plug is opened.
Regarding the discharge of this drain, it is known that the drain from the drain tank is diluted or neutralized before being drained through the bathtub (for example, Patent Document 1). It is also known that the drain from the drain tank is drained through the reheating pipe at a predetermined drainage timing (for example, Patent Document 2).

Japanese Patent Publication No. 2005-265228 Japanese Patent Publication No. 2009-270798

By the way, when the drain from the drain tank is discharged through the bathtub, the bathtub is simply used as a drainage route, and the drain is not mixed into the bathtub water. For this reason, when the drain from the drain tank is discharged into the bathtub from the circulation path and then drained into the drain pan from the bathtub's drain outlet, measures are taken to prevent any drain from remaining in the circulation path piping or the bathtub by supplying water to the bathtub through the circulation path after the drain has been discharged.
This type of drain discharge assumes that the bathtub plug is open. If the bathtub plug is accidentally closed, the drain being discharged will remain in the circulation system and the bathtub, and this drain will mix with the bathwater. Even if a predetermined amount of water or hot water is supplied for cleaning, if the plug is closed, the drain cannot be discharged from the bathtub. If the user closes the bathtub plug and switches to automatic hot water supply without noticing the drain discharge, there is a risk of this drain remaining. Furthermore, if the drain mixes with the bathwater, it is difficult to determine whether or not the drain has mixed with the bathwater because the drain is colorless and transparent.
Incidentally, the inventor of this application has found that when draining condensate into a bathtub, a certain amount of water is added to also clean the pipe through which the condensate has passed. Then, during the next automatic filling of the bathtub, the presence of condensate can be confirmed by whether or not the water level exceeds the circulation port with a water volume less than the initial water level. However, based on this finding, the inventor has also found that when a certain amount of water is supplied, the water level differs depending on the volume and shape of the bathtub, resulting in inconsistent results and sometimes making it impossible to confirm the presence of condensate.

Therefore, in view of the above problems, the object of the present invention is to determine the presence of residual drain by injecting water after drain discharge and to encourage the user to discharge the drain.
Another objective of the present invention, in view of the above-mentioned problems, is to improve the accuracy of drain discharge, which is not affected by the volume of the bathtub or the shape inside the bathtub, by determining the amount of drain remaining when a certain amount of water is added and part or all of the circulation port is submerged in water.

To achieve the above objective, according to one aspect of the drain discharge method of the present invention, a drain discharge method for discharging drain generated in a hot water supply system and stored in a drain tank through a bathtub, comprising the steps of: discharging the drain from the drain tank into the bathtub when bathtub water is being discharged from the bathtub, or when the drain in the drain tank exceeds a standard level and the circulation pump is driven so that the bathtub water does not flow into the circulation path connected to the bathtub ; and outputting alert information when the discharge of the drain from the drain tank is completed, and after filling the bathtub with enough water so that part or all of the circulation port is not submerged, the circulation pump is driven so that the bathtub water flows into the circulation path connected to the bathtub .

To achieve the above objective, according to one aspect of the drain discharge device of the present invention, a drain discharge device for discharging drain generated by a hot water supply system and stored in a drain tank through a bathtub includes: a level sensor for detecting the level of drain stored in the drain tank; a drain discharge passage for discharging the drain from the drain tank into the bathtub; a circulation passage and circulation pump for circulating the bathtub water in the bathtub; and a control unit that discharges the drain from the drain tank into the bathtub when the bathtub water is being discharged from the bathtub, or when the drain in the drain tank exceeds a reference level and the circulation pump is driven to prevent the bathtub water from flowing into the circulation passage, terminates the discharge of the drain from the drain tank, and after filling the bathtub with enough water so that part or all of the circulation port is submerged, drives the circulation pump to output alert information when the bathtub water flows into the circulation passage connected to the bathtub .

To achieve the above objective, according to one aspect of the present invention, the hot water supply device is a hot water supply device that discharges drain stored in a drain tank through a bathtub, and includes the drain discharge device.

According to the present invention, one of the following effects can be obtained.
(1) By adding water after draining, it is possible to determine if any drain remains, and by notifying the user or stopping the water supply, it is possible to encourage the user to drain the drain and prevent drain residue from remaining before adding water.
(2) If the bathtub stopper is closed, when an alert is output, the user can open the bathtub stopper, allowing a certain amount of water to be poured into the bathtub and drained, making it possible to fill the bathtub with water that does not contain drain.
(3) Since the drain remaining in the bathtub is diluted by the initial water filling, opening the bathtub stopper allows for drain discharge while also purifying the bathtub, making it possible to fill the bathtub with water that does not contain drain.

This figure shows a drain discharge device according to one embodiment. This is a flowchart showing the drain discharge process. Figure A shows the water level setting for the bathtub according to Example 1, and Figure B shows the bathtub data table. A is a front view showing the drain tank, and B is a side view showing the drain tank. This figure shows a hot water reheating device according to Example 1. This figure shows an example of a control unit for a hot water reheating system. This is a flowchart showing the drain discharge procedure 1. Figure A shows the initial water injection process, and Figure B shows the state before water injection. Figure A shows the state immediately before filling the bathtub with water, and Figure B shows the residual state of the bathtub water. This flowchart shows the first step in the fully automated driving process. This is a flowchart showing the second processing step for fully automated driving. Figure A shows a normal drainage condition, and Figure B shows an abnormal drainage condition. This is a flowchart showing the drain discharge procedure according to Example 2. This is a diagram showing a hot water reheating device according to Example 3.

[One Embodiment]
Figure 1 shows a drain discharge device in a water injection system according to one embodiment. The configuration shown in Figure 1 is just one example, and the present invention is not limited to this configuration.
This drain discharge device 2 is equipped with a drain discharge section 4, a water injection section 6, and an alert output section 8, and the drain D generated by heat exchange is collected in a drain tank 10 and discharged from the bathtub 14 through a circulation path 12.

The drain discharge unit 4 discharges the drain at either the timing of draining the bathtub 14 by opening the bathtub plug 16, or the timing of draining when it is confirmed that the drain D exceeds a reference level Dref, which is an example of a drain tank 10, and that no water flow is generated by the circulation of bathtub water BW by the circulation pump 18. The presence or absence of water flow is detected by a water flow switch 20, which is an example of a water flow detection means.
The water inlet 6 injects a fixed amount of water after the drain D has been discharged. This fixed amount of water is injected into the empty bathtub 14 with the bathtub stopper 16 closed, which also serves to clean the drain discharge circuit described later. Even if the initial injection is less than the amount of water needed to submerge part or all of the circulation port 22, the added water volume will be enough to submerge part or all of the circulation port 22. This injection can be either pre-heating water or post-heating hot water.
The alert output unit 8 outputs alert information indicating that drain D remains in the bathtub 14 if part or all of the circulation port 22 is submerged by the initial water injection into the bathtub 14 by the water injection unit 6, that is, if water flow is generated by the circulation of bathtub water BW by the circulation pump 18. The presence or absence of water flow can be confirmed by the output of the water flow switch 20.

<Drain discharge process>
Figure 2 shows a drain discharge and abnormal discharge detection process according to one embodiment. This process is an example of a drain discharge method in which drain D generated by heat exchange is stored in a drain tank 10 and discharged from the bathtub 14 through a circulation path 12, and includes drain D discharge, drain D discharge determination, water injection, bathtub 14 water level determination, and output of alert information.
Regarding the discharge of drain D, it is determined whether it is the first or second discharge timing (S11). The first discharge timing is the timing when the bathtub 14 is drained by opening the bathtub stopper 16. The second discharge timing is the timing when it is confirmed that the drain D exceeds the aforementioned standard level Dref in the drain tank 10 and that no water flow is generated by the pump circulation of the bathtub water BW. This timing occurs, for example, when the drain D exceeds the upper level Href (Figures 4 and 5) above the standard level Dref.

If it is the first or second discharge timing (YES in S12), the drain D from the drain tank 10 is discharged into the bathtub 14 from the drain discharge circuit including the circulation path 12 (S13). In this case, a drain discharge circuit is established from the drain tank 10 through the circulation path 12 to the circulation port 22 to perform drain discharge. The drain discharge circuit is the discharge path of the drain D from the drain tank 10 to the bathtub 14, or from the drain tank 10 to outside the bathtub 14 when the bathtub plug 16 is opened.
The system determines whether the drain D has been completely discharged (S14). If the drain D has been completely discharged from the drain tank 10 (YES in S14), a fixed amount of water W1, equivalent to, for example, 3 cm of the bath water level, is injected from the water injection unit 6 to clean the drain discharge circuit, including the circulation path 12 (S15). This completes the drain discharge.

During water refilling after draining, a fixed amount of initial water is injected into the bathtub 14 from the water injection port 6 (S16). This initial water injection amount is less than the amount of water required to partially or completely submerge the circulation port 22, by a water volume W2 corresponding to, for example, 2 cm of the bathtub water level. During this water injection, the bathtub plug 16 is in the closed position.

It is determined whether part or all of the circulation port 22 is submerged by this water injection (S17). This determination can be made, for example, by checking whether there is a water flow due to the circulation of bath water BW by the circulation pump 18.
If part or all of the circulation port 22 is not submerged (NO in S17), drain D is being discharged from the bathtub 14, so no alert information is output (S18). If part or all of the circulation port 22 is submerged (YES in S17), an alert is output indicating that drain D remains in the bathtub 14, or an alert indicating that water supply has stopped (S19). This alert prompts the user to open the bathtub stopper 16, i.e., drain the bathtub.

<Effects of one embodiment>
According to this embodiment, the following effects can be obtained.
(1) When filling the bathtub with water next time, i.e., when filling it with hot water, the remaining drain from the previous time can be detected by an alarm during the initial hot water supply.
(2) If there is an alarm indicating that the water supply has stopped or an alarm indicating that drain water remains, the bathtub should be drained at that point to prevent drain water from remaining.

<Bathtub water level setting>
Figure 3A shows the water level setting for the bathtub according to Example 1. In Figure 3A, the same parts as in Figure 1 are denoted by the same reference numerals.
A circulation port 22 is provided on the side of the bottom of the bathtub 14, to which a circulation passage 12 (Figure 1) is connected. The height of this circulation port 22 is set so that its center is at a certain height, for example, about 15 cm, from the bottom surface 26 of the bathtub.

In the bathtub 14, an initial water level Lini, a reference water level Lst, and multiple set water levels Ln, for example L1, L2, L3...L11, are set at height intervals from the bottom surface 26 of the bathtub.
The initial water level Lini is the water level near the center of the circulation port 22, and is the water level at which the return pipe 12-1 of the circulation path 12 is submerged.
The reference water level Lst is set to a certain height, for example, about 8 cm, above the initial water level Lini.
The set water level L1 is set to a certain height, for example, about 3 cm, above the reference water level Lst, and each set water level L1, L2, L3...L11 has a certain width in the height direction, for example, about 3 cm. The bathtub water level can be selected from the set water levels L1, L2, L3...L11.

The height from the bottom surface of the bathtub 26 to the set water level L1 is,
The height of the set water level L1 = 15 [cm] + 8 [cm] + 3 [cm]
=26 [cm] ...(1)
Therefore, the height from the bottom surface of the bathtub 26 to the set water level L11 is,
Height of set water level L11 = 15 [cm] + 8 [cm] + 3 [cm] × 11
=56 [cm] ...(2)
is.

If the resolution of the bathtub water level sensor 24 is 1 bit = 0.2125 [cm], then the height of each step in the set water levels L1 to L11 is 3 [cm], so 14 bits = 2.975 [cm].
Vini is the initial water volume from the bottom surface 26 of the bathtub, including the water volume in the piping, up to the initial water level Lini. Vst is the standard water volume from the initial water level Lini to the standard water level Lst. Vd is the water volume from the standard water level Lst to the set water level L1 (=Ld). These water volumes will vary depending on the piping and the bathtub 14.

<Bathtub Data Table 28>
Figure 3B shows the bathtub data table. This bathtub data table 28 is a database of bathtub data, and stores information such as the installation information of the bathtub 14 and water level information.
This bathtub data table 28 stores bathtub information 30 and water level information 32, and the water level information 32 stores initial water level information 32-1, reference water level information 32-2, and set water level information 32-3.
The bathtub information 30 stores information such as the installation status and size of the bathtub 14.

The initial water level information 32-1 stores the water volume Vini from the bathtub bottom surface 26 to the initial water level Lini, including the water volume in the piping. The water volume Vini is the measurement value from the bathtub water level sensor 24.
The reference water level information 32-2 stores the reference water volume Vst from the initial water level Lini to the reference water level Lst. This reference water volume Vst is the measurement value from the bathtub water level sensor 24.
The set water level information 32-3 stores the water volume Vd, which is the unit water volume for each set water level from the reference water level Lst to the set water level L11.
This information is used to control the fully automatic hot water supply system, including drain discharge.

<Drain tank 10>
Figure 4A shows a longitudinal section of the drain tank 10, and Figure 4B shows a cross-section of Figure 4A along the line IVB-IVB. In this embodiment 1, the upper level Href and lower level Lref are set as the previously described reference level Dref.
The drain tank 10 is equipped with an inlet port 34, an outlet port 36, an overflow port 38, and a drain level sensor 40. Neutralized drain D is guided into the drain tank 10 from the inlet port 34 and stored there, and then discharged from the outlet port 36. When the drain D exceeds the upper limit level (overflow level) U, it is discharged outside the drain tank 10 from the overflow port 38.
The drain level sensor 40 is a sensor that detects the water level of drain D accumulated in the drain tank 10. This drain level sensor 40 is equipped with a common electrode 40-1, a lower level detection electrode 40-2, an upper level detection electrode 40-3, and an upper level detection electrode 40-4. The common electrode 40-1 is set to the submerged position of the drain D. In this drain tank 10, the common electrode 40-1 and the lower level detection electrode 40-2 detect the lower level Lref of the drain D, and the common electrode 40-1 and the upper level detection electrode 40-3 detect the upper level Href of the drain D. The upper level detection electrode 40-4 detects an upper level U that is higher than the upper level Href, and this upper level U is, for example, the overflow level.

<Hot water heating and reheating device 42>
Figure 5 shows a hot water reheating device 42 according to Embodiment 1 of the water supply system equipped with the drain discharge device 2 described above. This hot water reheating device 42 is an example of a hot water supply system. This hot water reheating device 42 is equipped with a hot water supply function for general hot water supply to areas other than the bathtub 14, a hot water supply function for filling the bathtub 14, and a reheating function for the bathtub water BW.

This hot water supply and reheating device 42 is equipped with a hot water supply combustion chamber 44-1 and a reheating combustion chamber 44-2. The hot water supply combustion chamber 44-1 is equipped with a primary heat exchanger 48 and a secondary heat exchanger 50. The primary heat exchanger 48 mainly exchanges the sensible heat of the combustion exhaust 54 obtained from the combustion of the burner 52 with the feedwater W, and the secondary heat exchanger 50 mainly exchanges the latent heat of the combustion exhaust 54 that has passed through the primary heat exchanger 48 with the feedwater W.
A heat exchanger 56 is provided in the combustion chamber 44-2 for reheating. The heat exchanger 56 exchanges the sensible heat of the combustion exhaust 60 obtained from the combustion of the burner 58 with the bath water BW. The heat exchangers 48, 50, and 56 can be operated in either bidirectional or independent modes, and it is possible to pour the hot water HW obtained from the heat exchange between the primary heat exchanger 48 and the secondary heat exchanger 50 into the bath 14.

Fuel gas supply pipes 62 are connected to burners 52 and 58, supplying fuel gas G. The fuel gas supply pipes 62 are equipped with a main gas solenoid valve 64 and a gas proportional valve 66. A switching solenoid valve 68, a gas solenoid valve 70, and a switching solenoid valve 72 are installed on the burner 52 side, while a gas solenoid valve 74 is installed on the burner 58 side. An air supply fan 76-1 is provided on the burner 52 side, and an air supply fan 76-2 is provided on the burner 58 side, supplying the air necessary for burner combustion. Therefore, for hot water supply, pouring, or reheating of bath water BW, the amount of gas burned by burners 52 and 58, necessary for controlling the hot water temperature, pouring temperature, and reheating temperature, is controlled by the opening degree of the gas proportional valve 66, etc.

The water supply W is supplied from the water supply pipe 80 to the secondary heat exchanger 50, and after passing through the secondary heat exchanger 50, it is led to the primary heat exchanger 48. The hot water HW after heat exchange in the heat exchangers 48 and 50 is led to the hot water supply pipe 82. A bypass pipe 86 is provided between the water supply pipe 80 and the hot water supply pipe 82, allowing the water supply W to be mixed with the hot water HW. The bypass pipe 86 mixes the water supply W with the hot water HW after heat exchange in order to improve the responsiveness to the set temperature during hot water supply. The hot water HW is injected into the bathtub 14 through the circulation path 12 via an injection pipe 88, which is an example of an injection section 6 (Figure 1). The injection pipe 88 is used for injecting water into the bathtub 14, and can be used for either the hot water HW after heat exchange or the water supply W before heat exchange.
The water supply pipe 80 is equipped with a water supply temperature sensor 90 and a water flow sensor 92, and the hot water supply pipe 82 is equipped with a hot water outlet temperature sensor 96, a water control valve 98, and a mixed temperature sensor 100. The bypass pipe 86 is equipped with a bypass solenoid valve 102.

The water supply temperature sensor 90 detects the water supply temperature. The water flow rate sensor 92 detects the amount of water flowing through the water supply pipe 80. The hot water outlet temperature sensor 96 detects the temperature of the hot water after heat exchange. The bypass solenoid valve 102 controls the amount of water supply W mixed with the hot water HW. The water control valve 98 is used to control the water supply amount and the hot water supply amount. The mixed temperature sensor 100 detects the temperature of the mixed water of hot water HW and water supply W.
The water supply pipe 88 is equipped with a hot water solenoid valve 104, a hot water volume sensor 106, and a check valve 108. The hot water solenoid valve 104 is used to adjust the amount of hot water supplied to the bathtub 14. The hot water volume sensor 106 measures the amount of hot water supplied. The check valve 108 is a means of disconnecting the water supply pipe 80 and the hot water supply pipe 82 from the bathtub water BW.

A drain receptacle 110 is provided on the secondary heat exchanger 50 side, and the condensate D generated during heat exchange is collected in this receptacle 110. The condensate D in the receptacle 110 is led through a drain pipe 112 to a neutralizer 113, where it is neutralized and then stored in a drain tank 10. The condensate D in the drain tank 10 is led through a drain pipe 114 to the return pipe 12-1 of the circulation path 12. A check valve 116 is provided in the drain pipe 114. The check valve 116 is a means of disconnecting the circulation path 12 from the drain pipe 114.

The circulation path 12 is equipped with temperature sensors 118 and 120, a two-way valve 122, a three-way valve 124, a circulation pump 18, and a bathtub water level sensor 24. The temperature sensor 118 detects the temperature of the bathtub water BW coming out of the bathtub 14. The temperature sensor 120 detects the temperature of the bathtub water BW entering the bathtub 14. The two-way valve 122 is used to open and close the circulation path 12. The three-way valve 124 is used to drain the drain D from the drain pipe 114 into the return pipe 12-1 of the circulation path 12. The circulation pump 18 is driven when reheating the bathtub water BW, pouring hot water HW into the bathtub 14, or discharging the drain D. The bathtub water level sensor 24 is used to detect the water level of the bathtub water BW in the bathtub 14.
This hot water heating and reheating device 42 is equipped with a control unit 128, and a bathroom remote control device and a kitchen remote control device (not shown) are provided as means for operation control and operation instructions.
In this hot water reheating device 42, the drain discharge section 4 is, for example, composed of a drain pipe 114, a circulation path 12, and a bathtub 14, but it is not limited to this configuration.

<Control Unit 128>
Figure 6 shows an example of a control unit 128. This control unit 128 includes a hot water supply control unit 130, which is composed of a computer; a bathroom remote control control unit 132, which is installed in the bathroom remote control device; and a kitchen remote control control unit 134, which is installed in the kitchen remote control device.
The hot water supply control unit 130 is equipped with a processor 136, a memory unit 138, a communication unit 140, and an input/output (I/O) unit 142. The processor 136 executes the OS (Operating System), hot water supply reheating program, drain discharge program, etc., stored in the memory unit 138. The memory unit 138 is composed of memory elements such as ROM (Read-Only Memory), RAM (Random-Access Memory), and EEPROM (Electrically Erasable Programmable Read-Only Memory). The ROM or EEPROM stores the OS, hot water supply reheating program, drain discharge program, and the bathtub data table 28 as the bathtub database described above.

The communication unit 140 is controlled by the processor 136 and is used for data communication with the communication unit 166 of the kitchen remote control control unit 134 and the communication unit 150 of the bathroom remote control control unit 132.
I/O 142 is used to take in the outputs of various devices such as the water flow switch 20, bathtub water level sensor 24, drain level sensor 40, hot water volume sensor 106, and drain timer 144, and to take in control outputs to devices such as the circulation pump 18, water control valve 98, hot water solenoid valve 104, two-way valve 122, and three-way valve 124.
The drainage timer 144 is used to measure a certain period of time, for example 3 minutes, as a waiting time when draining the drain D.

The bathroom remote control unit 132, like the hot water supply control unit 130, is equipped with a processor 146, a memory unit 148, a communication unit 150, and an I/O unit 152. The processor 146 performs coordinated control with the hot water supply control unit 130, as well as initiating automatic operation and providing notification of such operation, displaying control information, and outputting alerts for drain discharge abnormalities.
I/O 152 is used to receive input from the automatic driving switch 154, turn on or off the LED (Light Emitting Diode) 156 as an indicator, output the display from the liquid crystal display 158, and extract audio output from the speaker 160.

The kitchen remote control unit 134, like the hot water supply control unit 130, is equipped with a processor 162, a memory unit 164, a communication unit 166, and an I/O unit 168. The processor 162 performs coordinated control with the hot water supply control unit 130, as well as initiating automatic operation and providing notification of such initiation, displaying control information, and outputting alerts for drain discharge abnormalities.
I/O 168 is used to take input from the automatic operation switch 170, turn on or off the LED 172 as an indicator, output the display from the liquid crystal display 174, and take audio output from the speaker 176.

<Drain D discharge process>
Figure 7 shows the drain D discharge process of the hot water reheating device 42. Hot water HW after heat exchange is used for this drainage process. This process involves detecting the drain discharge timing and performing drain discharge. It is determined whether the drain level DL is above the upper level Href (DL ≥ Href) (S200). This drain level DL can be detected by the drain level sensor 40. If this drain level DL is above the upper level Href (YES in S200), it is time to discharge the drain, so steps S201 to S204 are skipped and the process moves to S205 to proceed to the drain discharge process. If the drain level DL is below the upper level Href (NO in S200), the bath water level is monitored by the bath water level sensor 24 to detect the drain discharge timing by opening the bath plug 16 (S201). The system determines whether the bathtub water level has fallen below the standard level (bathtub water level < standard level) due to the opening of the bathtub plug 16 and the drainage of bathtub water BW (S202). If the bathtub water level < standard level (YES in S202), the drain timer 144 is started (S203). The drain timer 144 times out after a certain period of time sufficient for the remaining bathtub water BW to be drained, for example, 3 minutes. The system determines whether the drain timer 144 has timed out (S204). The system waits until 3 minutes have elapsed, and after 3 minutes, the circulation pump 18 is driven to check for any remaining water in the bathtub 14 (S205). The presence or absence of remaining water can be determined by checking whether or not the remaining water flows into the circulation path 12 using the output of the water flow switch 20, which is an example of a water flow detection means.

The system determines whether there is any remaining water in the bathtub 14 (S206). If there is any remaining water in the bathtub 14 (NO in S206), the circulation pump 18 is stopped (S207), steps S208 to S215 are skipped, and this process is terminated without draining the drain D.
If there is no bath water BW (remaining bathwater) in the bathtub 14 (YES in S206), the circulation pump 18 is stopped (S208) and the drain discharge circuit is established (S209). The drain discharge circuit is the drain D discharge path from the drain tank 10 to the bathtub 14, or from the drain tank 10 to outside the bathtub 14 when the bathtub plug 16 is opened.
Figure 8A shows the initial water level, and Figure 8B shows the state when the bathtub 14 is empty. At timing S209, as shown in Figure 8B, the bathtub 14 and the circulation path 12 are empty.
After the drain discharge circuit is established, the circulation pump 18 is driven (S210) to discharge the drain D from the drain tank 10 to the bathtub 14 through the drain discharge circuit. While the circulation pump 18 is operating, it is determined whether the discharge of the drain D is complete (S211). The determination of the end of discharge may be made by measuring the time it takes for the discharge to be completed even if the drain D in the drain tank 10 is full, or by detecting that the level has fallen below the lower level Lref using the lower level detection electrode 40-2 of the drain tank 10 in Figure 4. If the discharge of the drain D is complete (YES in S211), the circulation pump 18 is stopped (S212) and the hot water supply circuit is established (S213). The hot water supply circuit is the hot water supply path from the hot water supply pipe 82 to the bathtub 14 through the water supply pipe 88 and the circulation path 12. The establishment of this hot water supply circuit is achieved by opening the hot water supply solenoid valve 104 of the water supply pipe 88, creating a state where hot water HW can be supplied to the bathtub 14. From this hot water supply circuit, a certain amount of hot water is poured into the bathtub 14, for example, a volume W1 of water corresponding to a bathtub water level of 3 [cm] (S214), which also serves to clean the circulation path 12. Then, for a predetermined time, the circulation pump 18 is driven to discharge any remaining water from the circulation path 12 (S215), and this process is completed.
If the bathtub stopper 16 is opened during the 3 minutes of S204, the bathtub 14 will be empty, as shown in Figure 9A. If the bathtub stopper 16 is closed during the 3 minutes of S204, assuming that drainage is complete in this state, the drainage will be incomplete. In other words, as shown in Figure 9B, the drain D and the amount of hot water W1 corresponding to the bathtub water level of 3 [cm] (S214) will remain in the bathtub 14, etc.

<Fully Automated Driving [1]>
Figure 10 shows the processing procedure for the fully automatic operation [1] of the hot water reheating device 42. This automatic operation [1] processing procedure is for acquiring water level information 32 (B in Figure 3) of the bathtub 14 when the hot water reheating device 42 is installed, etc.
This processing procedure requires that the automatic operation switch 154 or the automatic operation switch 170 be turned ON, and the ON state of the automatic operation switch 154 or the automatic operation switch 170 is a condition for performing data storage. It is determined whether the automatic operation switch 154 or 170 is ON (S301), and if the automatic operation switch 154 or 170 is ON (YES in S301), a predetermined amount, for example 10 liters, of hot water is poured (S302).
The circulation pump 18 is driven to check for the presence of remaining water (S303). If there is remaining water (NO in S304), steps S307 to S317 are skipped, the circulation pump 18 is stopped (S305), and after draining, a restart instruction is output from the remote control device (S306), ending this process.
If there is no remaining hot water (YES in S304), the circulation pump 18 is stopped (S307), a predetermined amount of hot water is poured again to fill the circulation path 12, then the two-way valve 122 is closed and hot water is poured from the supply pipe 12-2 (S308).

The processes in S309 to S314 are performed while the bathtub water level sensor 24 is filling the tub. It is determined whether the initial water level has been detected by the bathtub water level sensor 24 (S309). If the initial water level is detected (YES in S309), the sensor value Lini and water volume Vini are stored as the initial water level (S310).
At this point, as shown in Figure 8A, the bathtub 14 is filled to its initial water level, and the circulation path 12, etc., are filled with water. In other words, the water volume Vini includes the water volume in the piping.
S311 determines whether the water level sensor value has reached a predetermined level of Lini + 8 cm or higher (water level sensor value ≥ Lini + 8 cm).
If the water level sensor value is ≥ Lini + 8 [cm] (YES in S311), the sensor value (Lst = measured value - Lini) and water volume (Vst = measured value - Vinii) are stored as the reference water level (S312).
Here, the water volume W1 corresponding to a water level of 3 [cm] and the water volume W2 corresponding to 2 [cm] in this bathtub 14 are calculated and stored.
The following methods can be used to calculate W1 and W2.
Pattern 1: The standard height of the circulation port is 15 cm. Therefore, from the initial water volume Vini stored in S310,
W1=Vini/15×3...(3)
W2=Vini/15×2...(4)
Let's say.
Pattern 2: In S311, before detecting the reference water level Lst (initial water level Lini + 8 [cm]), the initial water level Lini + 3 [cm] is detected, and the amount of hot water poured after the initial water level detection when the initial water level Lini + 3 [cm] is reached is defined as W1. The water volume W2 is calculated using W1.
W2=W1/3×2...(5)
Let's say.
The calculation method is not limited to the above method; any amount of water W1 corresponding to a water level of 3 [cm] and W2 corresponding to a water level of 2 [cm] in each bathtub 14 is acceptable.
The water supply continues, and it is determined whether the water level sensor value is above the set water level (water level sensor value ≥ set water level) (S314). If the water level sensor value ≥ set water level (YES in S314), the water volume Vd per stage is stored as the set water level (S315).
After recording the water volume Vd, the hot water supply is stopped, the two-way valve is opened (S316), the circulation pump 18 is driven, and the water is reheated until the set temperature is reached (S317), and this process is completed.

<Fully Automated Driving [2]>
Figure 11 shows the processing procedure for the fully automatic operation [2] of the hot water reheating device 42. This automatic operation [2] processing procedure is the operation after data storage by automatic operation [1] (Figure 8).
In this processing procedure, it is determined whether the automatic operation switch 154 or 170 is ON (S401). If the automatic operation switch 154 or 170 is ON (YES in S401), it is determined whether drain discharge occurred last time (S402). This is to confirm whether the draining process shown in Figure 7 was recently performed on the bathtub 14 and whether the processes from S208 onwards were executed. If there was no drain discharge last time (NO in S402), S403 to S409 are skipped and the process proceeds to S410.
If drain discharge occurred last time (YES in S402), the bathtub water level sensor 24 checks for the presence of remaining water (S403).

If there is any remaining hot water (NO in S404), it is determined that water was added after draining without passing through the hot water reheating device 42, and steps S405 to S409 are skipped, and the system proceeds to S410.
If there is no remaining hot water (YES in S404), the final state of the discharge process in Figure 7 is shown in Figure 9A or Figure 9B, and in this state, the initial amount of hot water (= initial water volume Vini-W2) is poured in (S405).
As a result, in the case of Figure 9A, the state shown in Figure 12A occurs, and the water level does not reach the initial level Lini. Also, in the case of Figure 9B, the state shown in Figure 12B occurs, and the water level exceeds the initial level Lini.
The circulation pump 18 is driven (S406), and it is determined whether the water flow switch 20 is ON or OFF (S407). If the water flow switch 20 is ON (YES in S407), the state shown in Figure 12B is met, and therefore, a warning sound or/or a warning display is output as a drainage abnormality (S408), and this process is terminated.
If the water flow switch 20 is not turned ON (NO in S407), the circulation pump 18 is stopped (S409), the amount of water up to the set water level is poured in (S410), and the water is heated to the set temperature (S411).
Furthermore, the re-injection of hot water after drainage may be configured to occur after an alert is issued and the alert is cleared after drainage.

<Effects of Example 1>
According to this embodiment 1, the following effects can be obtained.
(1) When draining drain D, even if the bathtub stopper 16 of the bathtub 14 is accidentally closed, the next time the bathtub is filled with hot water, the abnormality can be automatically detected from the water level after the initial filling of the bathtub 14, and the abnormality can be notified by an alert output.
(2) This alert can be announced by voice or display from the bathroom remote control device or the kitchen remote control device, allowing the user to easily recognize any abnormality in drain discharge.

(3) If an abnormality in drain discharge is detected, the bathtub stopper 16 should be opened at that time, and the bathtub 14 should be emptied.
(4) Abnormalities in drain discharge can be determined by the initial amount of hot water poured, and if an abnormality occurs, the drain D can be discharged outside the bathtub, and the bathtub 14 can be cleaned at the same time with the initial amount of hot water poured.
(5) If there is an abnormality in the drain discharge, the hot water supply will be stopped after the alert is issued, thus preventing wasted hot water.
(6) In Example 1, after the drain D is discharged, a certain amount of water is poured in as a washing rinse, so the accuracy of detecting abnormal discharge when there is little drain D remaining can be improved, and the residue of drain D can be prevented.
(7) When the volume of the bathtub is large, if a certain amount of hot water is added, for example, 15 liters, the water level will be about 1 cm or less. Also, in bathtubs with a small area around the circulation port, such as bathtubs for half-body bathing, a certain amount of hot water added, for example, 15 liters, is too much, and the water level will be far above the circulation port. In Example 1, however, the amount of water to be judged is determined according to the individual installation situation and bathtub, so these inconveniences can be resolved. For example, the amount of hot water added after draining the condensate is set to an amount W1 that corresponds to a water level of 3 cm, based on the bathtub area at the height of the circulation port, and the amount of hot water added is less than the initial amount W2 that corresponds to a water level of 2 cm, so the accuracy of water level judgment can be improved. In other words, an amount of hot water equivalent to a water level of 3 cm is added after draining the condensate, and when the bathtub is automatically filled again, hot water is added to a water level 2 cm lower than the position of the circulation port 22, and if the circulation port 22 is submerged at that time, it can be determined that drained water remains.
(8) The bathtub water level can be measured by a water level sensor, and the water volume can be measured by a water volume sensor 92 and a water volume sensor 106. Considering the measurement errors and residual water in the pipes, the bathtub water level should be estimated to be around 1 cm. In this embodiment, the following patterns 1 and 2 can be assumed as examples of methods for calculating the water volume.
In Pattern 1, the standard height of the circulation port 22 is assumed to be 15 cm. When the initial water level is detected, the amount of water per 1 cm is calculated from "the amount of water injected up to that point / 15". This allows the amount of water for 2 cm = W2 and 3 cm = W1 to be calculated.
In Pattern 2, after detecting the initial water level, the amount of water up to the initial water level + 3 cm is detected by the bathtub water level sensor 24 connected to the circulation port 22, which drains water when the drain is discharged. The amount of water up to a 3 cm rise from this detected water level is defined as the amount of water added after drain discharge W1, and 2/3 of that amount is defined as the amount of water W2 which is reduced from the initial water volume. In either Pattern 1 or Pattern 2, the accuracy of determining the presence of drain D can be improved.

<Drain D discharge process>
Figure 13 shows the processing procedure for the discharge of drain D according to Example 2.
In the processing procedure of this embodiment 2, the drain discharge timing is detected and the drain is discharged in the same manner as in the discharge process of embodiment 1. It is determined whether the drain level DL is equal to or greater than the upper level Href (DL ≥ Href) (S500). This drain level DL can be detected by the drain level sensor 40. If this drain level DL is equal to or greater than the upper level Href (YES in S500), it is the drain discharge timing, so steps S501 to S504 are skipped and the process proceeds to S505, and the drain discharge process begins. If the drain level DL is less than the upper level Href (NO in S500), the bath water level is monitored (S501) to detect the timing of drain discharge by opening the bath plug 16, it is determined that the bath water level is less than the standard water level (S502), if the bath water level is less than the standard water level, the drain timer 144 is started (S503), the drain timer 144 is determined to have timed out (S504), the circulation pump 18 is driven, the remaining water is checked (S505), and after determining the amount of water remaining in the bath 14 (S506), if there is water remaining in the bath 14 (NO in S506), the circulation pump 18 is stopped (S507), steps S508 to S516 are skipped and the process ends, and no drain D is discharged.

If there is no bath water BW (remaining bathwater) in the bathtub 14 (YES in S506), the circulation pump 18 is stopped (S508), and it is determined whether the drain level DL is less than the lower level Lref (DL < Lref) (S509). This drain level DL can be detected by the drain level sensor 40.
If DL < Lref (YES in S509), there is no drain D to be discharged, so steps S510 to S513 are skipped and the process proceeds to S514 in order to perform normal pipe cleaning. In this case, the amount of hot water poured in S515 may be a predetermined amount sufficient to clean the circulation path 12, for example, 10 liters.
If DL < Lref (NO in S509), the drain discharge circuit is established (S510), the circulation pump 18 is driven (S511), and the drain D is discharged from the drain tank 10 to the bathtub 14 through the drain discharge circuit.
Determine whether the drain level DL is less than the lower level Lref (DL < Lref) (S512).
If DL < Lref (NO in S512), drain D continues. If DL < Lref (YES in S512), the circulation pump 18 is stopped (S513) and the hot water supply circuit is established (S514).
A certain amount of hot water is poured from the hot water supply circuit into the bathtub 14, which also serves to clean the circulation path 12, for example, a volume W1 of water corresponding to the bathtub water level of 3 [cm] (S515). Then, the circulation pump 18 is driven for a predetermined time to discharge any remaining water from the circulation path 12 (S516), and this process is completed.

<Effects of Example 2>
According to this embodiment 2, the following effects can be obtained.
(1) If no drain has accumulated, the drain discharge process can be omitted, and the drain discharge process can be performed only when drain D has accumulated, thereby improving the efficiency of the process.
(2) The drain level DL of the drain tank 10 can be monitored, and the drain D accumulated in the drain tank 10 can be reliably discharged.
(3) The drain level DL of the drain tank 10 is monitored, and the circulation pump 18 is driven only until the drain D accumulated in the drain tank 10 falls below the lower level Lref, which is the reference level. This minimizes the pump driving time for drain discharge.

Figure 14 shows a hot water reheating device 42 according to Example 3. This Example 3 is a configuration of the hot water reheating device 42 of Example 1 at a specific implementation level.
In this embodiment 3, the combustion chambers 44-1, 44-2 and intake fans 76-1, 76-2 of embodiment 1 are configured as a single combustion chamber 44 and a single intake fan 76, resulting in a more compact design.
The burner 52 side is equipped with an exhaust port 178, and the burner 58 side is equipped with an exhaust port 180, ensuring ventilation within the device.
Since the other components are the same as those in Figure 5, the same reference numerals are used for the same parts, and the explanation of each component is omitted.

<Effects of Example 3>
According to this embodiment 3, the same effects as those described above in one embodiment, embodiment 1, and embodiment 2 can be obtained, and in addition to making the device more compact, it is possible to prevent the residue of drain D in the bathtub 14 and to clean the inside of the bathtub 14 in a hot water reheating device that can be operated fully automatically.

[Other embodiments]
(1) In the above embodiments, the discharge of drain D is described separately in Embodiment 1 and Embodiment 2, but a configuration that includes both of these may be used.
(2) In the above embodiments, the hot water supply and reheating functions have been described, but the present invention may also be applied to a hot water supply, reheating, and heating system equipped with a heating function, or to a heat transfer medium heating system.
(3) In the drain discharge process (Figure 7), although pouring hot water is shown as an example in S214, water may be poured instead of hot water, without burner combustion and heat exchange.

As described above, the most preferred embodiments of the drain discharge method, drain discharge device, and hot water supply device have been explained. The present invention is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the invention as described in the claims or disclosed in the embodiments for carrying out the invention. It goes without saying that such modifications and changes are included within the scope of the present invention.

According to the present invention, even if the bathtub stopper is accidentally closed when draining drain D into the bathtub, the abnormality in drain D can be detected by the water filling operation, and the abnormality is notified by an alert, thus preventing the inconvenience of residual drain and proving beneficial.

D Drain W Water supply HW Hot water BW Bathtub water 2 Drain discharge device 4 Drain discharge section 6 Water injection section 8 Alert output section 10 Drain tank 12 Circulation path 14 Bathtub 16 Bathtub plug 18 Circulation pump 20 Water flow switch 22 Circulation port 24 Bathtub water level sensor 26 Bathtub bottom 28 Bathtub data table 30 Bathtub information 32 Water level information 32-1 Initial water level information 32-2 Standard water level information 32-3 Set water level information 34 Inlet port 36 Outlet port 38 Overflow port 40 Drain level sensor 42 Hot water supply and reheating device 44 Combustion chamber 44-1 Combustion chamber for hot water supply 44-2 Combustion chamber for reheating 48 Primary heat exchanger 50 Secondary heat exchanger 52 Burner 54 Combustion exhaust 56 Heat exchanger 58 Burner 60 Combustion exhaust 62 Fuel gas supply pipe 64 Main gas solenoid valve 66 Gas proportional valve 68 Switching solenoid valve 70 Gas solenoid valve 72 Switching solenoid valve 74 Gas solenoid valve 76-1, 76-2 Intake fan 80 Water supply pipe 82 Hot water supply pipe 86 Bypass pipe 88 Inlet pipe 90 Water supply temperature sensor 92 Water volume sensor 96 Outlet water temperature sensor 98 Water control valve 100 Mixing temperature sensor 102 Bypass solenoid valve 104 Inlet solenoid valve 106 Inlet water volume sensor 108 Check valve 110 Drain receiver 112, 114 Drain pipe 113 Neutralizer 116 Check valve 118, 120 Temperature sensor 122 Two-way valve 124 Three-way valve 128 Control unit 130 Hot water supply control unit 132 Bathroom remote control unit 134 Kitchen remote control unit 136, 146, 162 Processor 138, 148, 164 Memory unit 140, 150, 166 Communication unit 142, 152, 168 Input/output unit 154, 170 Automatic operation switch 156, 172 LED
158, 174 LCD display; 160, 176 Speaker; 178, 180 Exhaust vent

Claims (3)

A method for draining condensate generated by a hot water supply system and stored in a drain tank, which is then discharged through a bathtub.
When the bath water is being discharged from the bathtub, or when the drain in the drain tank exceeds a standard level and the circulation pump is driven so that the bath water does not flow into the circulation path connected to the bathtub , the process of discharging the drain from the drain tank into the bathtub,
The process includes: ending the discharge of the drain from the drain tank, filling the bathtub with enough water so that part or all of the circulation port is not submerged, and then driving the circulation pump to output alert information when the bathtub water flows into the circulation path connected to the bathtub ;
A drain discharge method, including the following. A drain discharge device that discharges condensate generated by a hot water supply system and stored in a drain tank through a bathtub,
A level sensor for detecting the level of drain stored in the drain tank,
A drain discharge passage for discharging the drain from the drain tank into the bathtub,
A circulation path and circulation pump for circulating the bath water in the aforementioned bathtub,
A control unit that outputs alert information when, while the bath water is being drained from the bathtub, or when the drain in the drain tank exceeds a standard level and the circulation pump is driven but the bath water does not flow into the circulation path, discharges the drain from the drain tank into the bathtub, ends the discharge of the drain from the drain tank, fills the bathtub with enough water so that part or all of the circulation port is not submerged, and then drives the circulation pump so that the bath water flows into the circulation path connected to the bathtub ,
A drain discharge device, including a drain discharge device. A hot water supply system that discharges drain water stored in a drain tank through a bathtub, comprising the drain discharge device described in claim 2.