Bath equipment

Abstract

To accurately detect entering / leaving from a bathtub during a reheating circulation operation by using a water level sensor of the bathtub, without affected by temperature change of bathtub water during the reheating circulation operation.SOLUTION: A determination section determines a bathtub entering state or leaving state on the basis of a water level detection value of a bathtub by a water level detector during stop of a reheating circulation operation. A generation section generates a reference water level to be applied in the determination of the determination section. The generation section periodically updates the reference water level according to the water level detection value before a prescribed time from the present in the bathtub leaving state during stop of the reheating circulation operation; on the other hand, stops the updating of the reference water level in the bathtub entering state or during the execution of the reheating circulation operation. The generation section corrects the reference water level on the basis of the amount of change of the temperature of hot water / cold water in the bathtub before and after the execution of the reheating circulation operation when the reheating circulation operation is terminated. The determination section determines the bathtub entering state when an increase amount of the present water level detection value to the corrected reference water level becomes a determination value or more after the execution of the reheating circulation operation.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a bath apparatus. [Background technology]

[0002] For example, Japanese Patent Laid-Open Publication No. 2003-83606 (Patent Document 1) discloses a bath device that detects the presence of a bather based on the detected water level of the bathtub, i.e., detects when a person enters and leaves the bathtub. The bath device described in Patent Document 1 is configured to detect when a person enters and leaves the bath by detecting changes (rising or falling) in the water level within a certain time interval.

[0003] On the other hand, if the water level sensor that detects the water level in the bathtub is a pressure sensor and is configured to detect the water level in the bathtub based on the water pressure in the circulation path for circulating the hot water in the bathtub within the hot water supply device, the hot water in the circulation path is pressurized by the operation of the circulation pump, and an error occurs in the water level detection value by the water level sensor. Therefore, the water level detection value during the reheating circulation operation by the operation of the circulation pump cannot be used. Therefore, by detecting the change in the water level detection value before and after the reheating circulation operation, bathing and leaving during the reheating circulation operation are detected (for example, see JP 2020-73857 A (Patent Document 2)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-83606 A [Patent Document 2] JP 2020-73857 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the bathtub is installed on an upper or lower floor, the water level detection value changes due to changes in density accompanying changes in the temperature of the hot water in the circulation path, and therefore the change in the water level detection value before and after the reheating circulation operation will include a change due to the change in temperature of the hot water, which may result in incorrect detection of bathing and leaving the bath.

[0006] The present invention has been made to solve such problems, and its object is to accurately detect when a person enters or exits a bath using a bathtub water level sensor without being affected by changes in the temperature of the bathtub water during reheating and circulation operation. [Means for solving the problem]

[0007] In one aspect of the present invention, a bathing device including a bathtub includes a water heater, a circulation path, a water level detector, a first temperature sensor, a control unit, a determination unit, and a generation unit. The circulation path has a circulation pump and circulates hot water in the bathtub between the water heater and the bathtub. The water level detector detects the water level in the bathtub based on the water pressure in the circulation path. The first temperature sensor detects the temperature of the hot water in the bathtub. The control unit controls the reheating circulation operation by operating the circulation pump. The determination unit determines whether the bath is in a bathing state or a leaving-bathing state based on the water level detection value of the bathtub by the water level detector while the reheating circulation operation is stopped. The generation unit generates a reference water level used by the determination unit to determine the bathing state and the leaving-bathing state. When the bathing state is left and the reheating circulation operation is stopped, the generation unit periodically updates the reference water level according to the water level detection value a predetermined time before the present, while the generation unit stops updating the reference water level while the bathing state or the reheating circulation operation is being performed. The generating unit further corrects the reference water level based on the amount of change in the temperature of the hot and cold water before and after the reheating circulation operation is performed, which is calculated from the detection value of the first temperature sensor, when the reheating circulation operation is completed. The determining unit determines that the bathing state is occurring when the amount of increase in the current water level detection value relative to the corrected reference water level is equal to or greater than a predetermined determination value for a predetermined first time or more after the reheating circulation operation is performed. Effect of the Invention

[0008] According to the present invention, bathing entry and exit can be accurately detected using the bath water level sensor without being affected by temperature changes in the bath water during bathing operation. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a hot water supply system including a bath device according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a conceptual diagram illustrating detection of bathing entry and exit using the detection value of a water level sensor. [Diagram 3] 10 is a schematic waveform diagram for explaining bathing entry / exit determination according to the present embodiment. FIG. [Figure 4] 10 is a schematic waveform diagram for explaining bathing entry / exit determination according to the present embodiment. FIG. [Diagram 5] 11 is a flowchart for explaining a process for generating a reference water level and a process for determining whether to enter or leave the bath. [Figure 6] FIG. 1 is a conceptual diagram illustrating classifications of bathtub placement heights. [Figure 7] 11 is a conceptual diagram illustrating a change in the detected water level value depending on the height at which the bathtub is placed. FIG. [Figure 8] FIG. 11 is a conceptual waveform diagram for explaining a concern. [Figure 9] 5 is a flowchart for explaining a process for correcting a reference water level according to the present embodiment. [Figure 10] 5 is a flowchart for explaining a process for correcting a reference water level according to the present embodiment. [Figure 11] 11 is a flowchart for explaining the processing procedure of S22 in FIG. 10; [Figure 12] 1 is a conceptual waveform diagram for explaining a first example of correction of the reference water level and bathing entry / exit determination according to the present embodiment. FIG. [Figure 13] 13 is a conceptual waveform diagram for explaining a second embodiment of the correction of the reference water level and the determination of bathing entry and exit according to the present embodiment. FIG. [Figure 14] 13 is a conceptual waveform diagram for explaining a third embodiment of the correction of the reference water level and the determination of bathing entry and exit in this embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are designated by the same reference characters, and their description will not be repeated in principle.

[0011] (Example of hot water system configuration) FIG. 1 is a schematic diagram of a hot water supply system including a bath apparatus according to this embodiment.

[0012] 1, hot water supply system 300 includes hot water supply device 100. Hot water supply device 100 includes a hot water supply circuit 5, a reheating circuit 7, a circulation path 8, and a controller 12. Hot water supply device 100 includes a bathtub 20 installed in a bathroom 200 as a hot water supply destination, in addition to a hot water tap and the like (not shown).

[0013] The hot water supply circuit 5 is configured to include a heating mechanism (not shown) for heating the introduced low-temperature water. The heating mechanism may be configured to utilize, for example, heating using heat from combustion of fuel such as gas or oil, or heating using exhaust heat during power generation or a heat pump. The hot water supply circuit 5 may be configured to directly discharge heated high-temperature water, or may be configured as a hot water storage type that stores heated high-temperature water.

[0014] The hot water supply circuit 5 can output hot water at a temperature set by the user by operating the heating mechanism. On the other hand, when the heating mechanism is stopped, low-temperature water is output from the hot water supply circuit 5 without being heated.

[0015] The hot water outlet path (not shown) of the hot water supply circuit 5 is connected to the hot water supply pipe 13a leading to the bathtub 20. The bath hot water supply valve 13 is interposed and connected to the hot water supply pipe 13a. The bath hot water supply valve 13 can be configured, for example, by a solenoid valve that can be controlled to open and close. By opening the bath hot water supply valve 13, a path can be formed through which hot water is output from the hot water supply circuit 5 to the hot water supply pipe 13a. This allows the hot water supply device 100 to include the bathtub 20 as a hot water supply destination in addition to a hot water tap, etc. In the following, the operation of supplying hot water or water to the bathtub 20 via the hot water supply pipe 13a by opening the bath hot water supply valve 13 regardless of the output temperature from the hot water supply circuit 5 is referred to as "hot water pouring". A flow rate sensor (not shown) is provided in the hot water supply pipe 13a, and the flow rate sensor can detect the hot water supply flow rate.

[0016] The circulation path 8 is for circulating hot water 21 in the bathtub 20 (hereinafter also referred to as "bathtub water 21") within the water heater 100, and has a return pipe 8a, a forward pipe 8b, and a circulation pump 10. One end of the return pipe 8a is connected to a circulation adapter 25 in the bathtub 20, and the other end is connected to the input side of the reheating circuit 7. One end of the forward pipe 8b is connected to the output side of the reheating circuit 7, and the other end is connected to the circulation adapter 25.

[0017] By operating the circulation pump 10, a path (reheating circulation path) is formed in which bath water 21 drawn in from the circulation adapter 25 passes through the return pipe 8a, the reheating circuit 7, and the forward pipe 8b and is discharged from the circulation adapter 25. The reheating circuit 7 can be configured to include a heating mechanism (not shown) that uses the heat of combustion of fuels such as gas and oil. The reheating circuit 7 operates when the reheating circulation path is formed, heating the bath water 21 introduced from the return pipe 8a and outputting it to the forward pipe 8b. The heated bath water 21 is supplied to the bathtub 20 by the forward pipe 8b, allowing for a reheating operation that raises the temperature of the bath water 21.

[0018] A temperature sensor 9 and a water level sensor 11 are connected to the return pipe 8a. The temperature sensor 9 can detect the temperature of the bath water 21. The temperature sensor 9 can be configured with, for example, a thermistor. The temperature sensor 9 corresponds to one embodiment of the "first temperature sensor."

[0019] The water level sensor 11 is composed of, for example, a pressure sensor, and detects the level of the bath water 21 in the bathtub 20 (hereinafter simply referred to as the "bath water level") based on the water pressure of the bath water 21. The temperature sensor 9 and the water level sensor 11 are disposed in an area in the return pipe 8a where the bath water 21 enters, even when the circulation pump 10 is stopped. The water level sensor 11 corresponds to one embodiment of a "water level detector."

[0020] The water level sensor 11 may have temperature characteristics. The temperature characteristics of the water level sensor 11 can be defined as the ratio of the displacement of the output value when the ambient temperature is changed to the rated value to the full scale, with respect to the output value at a predetermined reference temperature. The ambient temperature of the water level sensor 11 can be detected by the temperature sensor 14. The temperature sensor 14 can be configured by a thermistor, for example. The temperature sensor 14 corresponds to one embodiment of the "second temperature sensor".

[0021] Return pipe 8a is further connected to hot water supply pipe 13a at connection point 8c. As a result, when hot water is poured from hot water supply device 100 while circulation pump 10 is stopped, a first hot water supply path is formed from hot water supply pipe 13a to bathtub 20 via connection point 8c and return pipe 8a, and a second hot water supply path is formed from hot water supply pipe 13a to bathtub 20 via connection point 8c, return pipe 8a, reheating circuit 7, and supply pipe 8b. This allows the bath to be filled by pouring hot water from hot water supply device 100.

[0022] In this way, hot water and cold water from water heater 100 (hot water pouring circuit) is supplied to bathtub 20 via the first and second hot water pouring paths, including circulation path 8. Bathtub 20 is provided with a drain plug 26.

[0023] The controller 12 can be configured to include, for example, a microcomputer. The controller 12 is electrically connected to the hot water supply circuit 5, the reheating circuit 7, the temperature sensors 9 and 14, the circulation pump 10, the water level sensor 11, and the bath hot water valve 13. The controller 12 is connected to a power source via electrical wiring (not shown) and receives a power supply. The values ​​detected by the temperature sensors 9 and 14 and the water level sensor 11 are input to the controller 12.

[0024] Furthermore, the controller 12 is communicatively connected to a remote control 30 and a remote control 50. Note that the communication between these devices may be in accordance with any known standard, and may be wired or wireless.

[0025] Remote control 30 is installed on the wall of bathroom 200 and is used to operate water heating apparatus 100. Remote control 30 includes a display unit 31 for displaying information, and an operation unit 32 for accepting input setting operations from the user, etc. Display unit 31 is typically configured with a liquid crystal panel, and is configured to be able to display the bathtub water level and temperature. Operation unit 32 is typically configured with push buttons or touch buttons, and is configured to be able to accept setting operations related to at least the bathtub water level and temperature.

[0026] Remote control 50 is installed outside bathroom 200 and is used to operate water heating apparatus 100. Remote control 50 is typically installed on a wall in the kitchen. Remote control 50 includes a display unit 51 for displaying information and an operation unit 52 for receiving input setting operations from a user or the like.

[0027] Display unit 51 is typically configured with a liquid crystal panel, and is configured to be able to display the hot water supply setting temperature, the bath setting temperature, etc. Operation unit 52 is typically configured with push buttons or touch buttons, and is configured to be able to accept setting operations related to the operation of water heating device 100.

[0028] Controller 12 controls the operation of water heating apparatus 100 so that water heating system 300 operates according to user instructions, based on input setting operations by a user or the like from remote controls 30, 50. Controller 12 corresponds to one embodiment of a "control unit".

[0029] As an example of this control, when automatic bath operation is instructed by operating remote controls 30, 50, controller 12 executes the operation of filling bathtub 20 with water. This water filling operation ends when the bath water level in bathtub 20 reaches the set water level due to hot water poured from water heater 100 and the bath water temperature detected by temperature sensor 9 reaches the bath set temperature.

[0030] In the hot water supply system 300, after the bathtub 20 has been filled with hot water, it is possible to set an automatic mode in which the water heater 100 maintains the temperature and water level of the bathtub water 21. When this automatic mode is selected, if the bathtub water temperature detected by the temperature sensor 9 falls below a reference temperature set in correspondence with the bath set temperature (for example, set 2 to 3°C lower than the bath set temperature), a reheating operation is automatically started for heat retention control. Furthermore, if the bathtub water level detected by the water level sensor 11 falls below the set water level, a hot water top-up operation is started to supply additional hot water from the water heater 100 to the bathtub 20.

[0031] (Bath entry / exit determination process) In the hot water supply system according to the present embodiment, the detection value of water level sensor 11 in bathtub 20 is used to detect whether or not a person is entering or leaving bathtub 20.

[0032] Fig. 2 shows a conceptual diagram explaining the detection of bathing entry and exit using the detection value of water level sensor 11. Referring to Fig. 2, when the bathtub 20 is finished filling with water, the bathtub water level detected by water level sensor 11 has reached the set water level. This state is initially set as the "exiting bathing state." The "exiting bathing state" corresponds to a state in which no bather is present in bathtub 20.

[0033] In the bathing state, when a predetermined bathing determination condition related to a rise in the water level is met, a transition from the bathing state to the bathing state, i.e., bathing, is detected. The "bathing state" corresponds to a state in which a bather is present in the bathtub 20. In contrast, in the bathing state, when a predetermined bathing determination condition related to a drop in the water level is met, a transition from the bathing state to the bathing state, i.e., leaving the bath, is detected.

[0034] 3 and 4 are schematic waveform diagrams for explaining bathing entry / exit determination according to this embodiment. With reference to Fig. 3 and Fig. 4, the water level detection value X may be the output value at each point in time of the water level sensor 11 as it is, or may be the output value from which noise (high frequency components) has been removed using a low-pass filter or the like.

[0035] If water level sensor 11 is a pressure sensor and is configured to detect the bathtub water level based on the water pressure in circulation path 8 for circulating bathtub water within water heater 100, the hot water in circulation path 8 is pressurized by the operation of circulation pump 10, causing an error in the water level detection value by water level sensor 11. When water heater 100 pours hot water into bathtub 20 (filling operation, topping up water operation, etc.), the hot water in circulation path 8 is also pressurized, causing an error in the water level detection value. If a water level detection value containing such an error is used to determine whether or not a bath has been entered or left, there is a possibility that the entry or exit of a bath will be erroneously detected. In this embodiment, a description is given of a bath entry or exit determination that takes into account a case in which the bathtub water level cannot be detected by water level sensor 11, such as when the bath is in operation.

[0036] In this specification, "bath operation" includes the circulation operation in which a reheating circulation path is formed by operating the circulation pump 10, and the hot water pouring operation in the bath filling operation and top-up operation. Circulation operations include circulation operations that involve combustion in the heating mechanism of the reheating circuit 7 in the reheating operation (reheating circulation operation), and circulation operations that do not involve combustion in the heating mechanism of the reheating circuit 7 (non-combustion circulation operation). Non-combustion circulation operations include, for example, non-combustion circulation operations in pipe cleaning operation after draining and air purging operation.

[0037] 3 and 4 show the waveform (solid line) of the detected water level value X. In the example of FIG. 3, the detected water level value X is temporarily stuck to the upper limit value Xmax due to the bath operation (reheating circulation operation) being performed during the period from time t2 to t3, and deviates from the actual bathtub water level (hereinafter also referred to as the "actual water level"). The actual water level rises in response to bathing at time ta during this bath operation. After the bath operation ends, the bather leaves the bath at time tb, causing the actual water level to fall.

[0038] In this embodiment, the reference water level Xref is used to determine whether the bathing state is in or out of the bath. The reference water level Xref is generated based on the water level detection value acquired when the bathing state is out of the bath and the bathing operation is not in progress. The waveform (dashed line) of the reference water level Xref is shown in Fig. 3 and Fig. 4.

[0039] The reference water level Xref is periodically updated in the bath exit state according to the water level detection value Xtx a certain number of Tx (seconds) before the present time when the bath operation is not in progress. When the bath operation starts at time t2, the updating of the reference water level Xref is stopped. At this time, the reference water level Xref is the water level detection value Xtx at time t1, which is Tx (seconds) before time t2, when the updating is stopped.

[0040] During the bath operation from time t2 onwards, the reference water level Xref is not updated. Therefore, the reference water level Xref is maintained at the water level detection value Xtx at time t1. This makes it possible to prevent the reference water level Xref from being generated using a water level detection value that includes an error.

[0041] When the bath operation ends at time t3, a normal water level detection value can be acquired, and the controller 12 determines whether to enter or exit the bath based on the current water level detection value Xtn and the reference water level Xref (the water level detection value Xtx at time t1).

[0042] Specifically, the controller 12 calculates the amount of water level change (amount of water level rise) ΔXtn from the reference water level Xref by subtracting the reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref).The controller 12 then compares the calculated amount of water level change ΔXtn with a preset bathing judgment value ΔXin.

[0043] The bathing determination value ΔXin can be determined in advance as a water level change amount corresponding to a predetermined volumetric increase or decrease, and stored in the controller 12. For example, when constructing the hot water supply system 300 including the installation of the bathtub 20, the constructor can input the model number or size of the bathtub 20 (data that can specify the cross-sectional area of ​​the bathtub 20), and the controller 12 can use the input value to calculate and store the bathing determination value ΔXin.

[0044] When the state in which the amount of water level change ΔXtn is equal to or greater than the bathing judgment value ΔXin continues for a predetermined period of Tj1 (seconds), the controller 12 judges that the user is in the bathing state (time t4). In the example of Fig. 3, the user is in the leaving bathing state before the bathing action is performed, so the controller 12 judges that a transition from the leaving bathing state to the bathing state (taking a bath) has occurred during the bathing action, and detects bathing. In this way, by continuing the judgment for Tj1 (seconds), it is possible to prevent erroneous detection of bathing due to a momentary rise in the water level.

[0045] When it is determined at time t4 that the bathing state is being held, the reference water level Xref continues to be stopped from being updated, and the reference water level Xref is maintained at the water level detection value Xtx at time t1.

[0046] The water level detection value X drops in response to leaving the bath at time tb. When the bath is not in operation, the controller 12 determines whether to enter or leave the bath based on the amount of water level change ΔXtn, which is the difference between the water level detection values ​​at intervals of Tx (seconds). Specifically, the controller 12 calculates the amount of water level change ΔXtn from before Tx (seconds) by subtracting the amount of water level change Xtx from before Tx (seconds) from the current water level detection value Xtn (ΔXtn=Xtn-Xtx), and compares the calculated amount of water level change ΔXtn with a preset leaving-bathing determination value ΔXout. The leaving-bathing determination value ΔXout is a negative value, and can be set in correspondence with the bathing determination value ΔXin.

[0047] When the state where the amount of water level change ΔXtn is less than the bathing decision value ΔXout continues for a predetermined period of Tj2 (seconds), the controller 12 determines that a transition from the bathing state to the bathing state has occurred and detects the user leaving the bath. That is, when the user is in the bathing state and not in the bathing mode, the user leaving the bath is detected when the amount of water level drop ΔXtn from before Tx (seconds) continues to be less than the bathing decision value ΔXout for Tj2 (seconds). In this way, the continued determination over Tj2 (seconds) prevents the user from erroneously detecting the user leaving the bath due to a momentary drop in the water level. The relationship Tx>Tj2 is set between the Tj2 (seconds) for the continued determination and the Tx (seconds) for generating the reference water level Xref.

[0048] When leaving the bath is detected at time t6, the update of the reference water level Xref is resumed. However, at time t6, when leaving the bath is detected, the water level detection value Xtx (the water level detection value obtained in the leaving state) from Tx (seconds) before does not exist, so the reference water level Xref is not updated.

[0049] At time t7, when Tx seconds have passed since the time of bathing withdrawal detection (time t6), if it is determined that there is a water level detection value Xtx from Tx seconds before, the update of the reference water level Xref is resumed. The reference water level Xref is updated to the water level detection value Xtx from time t7 (time t6), Tx seconds before.

[0050] In the example of Fig. 4, the detected water level value X rises in response to taking a bath at time ta, and then temporarily sticks to the upper limit value Xmax due to the execution of the bath operation (reheating circulation operation) from time t4 to t5. However, the actual water level drops in response to leaving the bath at time tb during the bath operation.

[0051] As described above, when in the bath exit state and not in bath operation, the reference water level Xref is periodically updated according to the detected water level value Xtx Tx (seconds) before the present. The controller 12 calculates the amount of water level change ΔXtn from Tx (seconds) before by subtracting the detected water level value Xtx Tx (seconds) before from the current detected water level value Xtn (ΔXtn=Xtn-Xtx), and compares the calculated amount of water level change ΔXtn with the bathing judgment value ΔXin.

[0052] When the amount of water level change ΔXtn from before Tx (seconds) exceeds the bathing judgment value ΔXin for Tj2 (seconds), the controller 12 detects bathing (time t3). In other words, when the user is in the bath exit state and not in the bathing mode, bathing is detected when the amount of water level rise ΔXtn from before Tx (seconds) exceeds the bathing judgment value ΔXin for Tj2 (seconds).

[0053] When bathing is detected at time t3, the updating of the reference water level Xref is stopped. The reference water level Xref at this time is the water level detection value Xtx at time t1, which is Tx (seconds) before time t3, when the updating is stopped. Furthermore, when the bath operation is started at time t4, the updating of the reference water level Xref is continued to be stopped. Therefore, during the bath operation from time t4 onwards, the reference water level Xref is maintained at the water level detection value Xtx at time t1.

[0054] When the bath operation ends at time t5, the controller 12 determines whether to enter or exit the bath based on the current water level detection value Xtn and the reference water level Xref (the water level detection value Xtx at time t1).

[0055] Specifically, the controller 12 calculates the amount of water level change (amount of water level rise) ΔXtn from the reference water level Xref by subtracting the reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref), and compares the calculated amount of water level change ΔXtn with the bathing determination value ΔXin. If the amount of water level change ΔXtn is less than the bathing determination value ΔXin and the state in which the amount of water level change ΔXtn is equal to or greater than the bathing determination value ΔXin does not continue for Tj1 (seconds), the controller 12 determines that the user is in the leaving bathing state (time t6).

[0056] When leaving the bath is detected at time t6, updating of the reference water level Xref is resumed. Specifically, when it is determined that the water level detection value Xtx from Tx (seconds) before is present at time t7, which is Tx (seconds) after leaving the bath is detected (time t6), updating of the reference water level Xref is resumed. The reference water level Xref is updated to the water level detection value Xtx at the time Tx (seconds) before time t7 (time t6).

[0057] (Reference water level generation process) Fig. 5 is a flow chart for explaining the process of generating a reference water level and the process of determining whether to enter or exit the bath. For example, the control process of each step shown in Fig. 5 can be realized by the controller 12 executing a program stored in advance. That is, in this embodiment, the controller 12 corresponds to one example of the "generation unit" and the "determination unit".

[0058] As shown in Fig. 5, controller 12 determines whether water heating apparatus 100 is in bath operation in step (hereinafter simply referred to as "S") 30. As described above, bath operation includes pouring water and circulating operation. If water heating apparatus 100 is not in bath operation (NO in S30), controller 12 determines whether the user is in a withdrawal state in S31.

[0059] If the user is in the leaving bath state (YES in S31), the controller 12 determines in S32 whether there is a water level detection value Xtx Tx (seconds) before the present. In S31, it is determined that the water level detection value Xtx Tx (seconds) before the present is not a water level detection value acquired in either the bathing state or during bath operation. In other words, it is determined whether the water level detection value Xtx Tx (seconds) before the present is a water level detection value normally acquired by the water level sensor 11 in the leaving bath state.

[0060] If there is a water level detection value Xtx from Tx seconds before the present (YES in S32), the controller 12 proceeds to S33 and reads out the water level detection value Xtx from Tx seconds before. At this time, by deleting some of the water level detection values ​​that have already been stored, the memory capacity used for bathing entry and exit determination can be reduced.

[0061] In step S34, the controller 12 updates the reference water level Xref by setting the detected water level value Xtx read out in step S33 as the reference water level Xref.

[0062] Returning to S30, if water heating apparatus 100 is in bath operation (YES in S30), controller 12 determines in S35 whether the bath operation has ended. When the bath operation has ended (YES in S35), it becomes possible for water level sensor 11 to detect the bathtub water level. Controller 12 then determines whether to enter or leave the bath based on reference water level Xref updated in S34 and current water level detection value Xtn.

[0063] Specifically, the controller 12 reads out the reference water level Xref in S36, and stores the current water level detection value Xtn in S37. In S38, the controller 12 compares the value (Xref+ΔXin) obtained by adding the bathing determination value ΔXin to the reference water level Xref read out in S36 with the current water level detection value Xtn. If Xref+ΔXin>Xtn (NO in S38), the controller 12 clears the timer value (Cnt=0) in S42, and determines in S43 that the user is in the leaving-bath state.

[0064] On the other hand, if Xref+ΔXin≦Xtn (YES in S38), the controller 12 proceeds to S39, where it counts up the timer value Cnt, and compares the counted-up timer value Cnt with a judgment value C(Tj1) in S40. The judgment value C(Tj1) is defined as the timer value Cnt that increases over the course of a predetermined period of Tj1 (seconds).

[0065] When the timer value Cnt is smaller than the judgment value C(Tj1) (NO in S40), the controller 12 skips S42 to maintain the timer value Cnt and judges that the bath is in the withdrawal state. After that, when the start timing arrives, the process from S30 onwards is started again.

[0066] On the other hand, if the timer value Cnt in S39 is equal to or greater than the judgment value C (Tj1) (YES in S40), the controller 12 judges in S41 that the user is in a bathing state. That is, when the state where Xref+ΔXin≦Xtn continues for Tj1 (seconds), the user is judged to be in a bathing state.

[0067] As described above, the bathing state or the exiting state is determined based on the amount of change in the water level detection value obtained after the bathing action relative to the reference water level Xref generated using the water level detection value obtained in the exiting state before the bathing action.

[0068] In the above configuration, the reference water level Xref is periodically updated according to the water level detection value Xtx acquired Tx (seconds) before the present time when the bath is being removed and not in operation. This allows the reference water level Xref to reflect changes in the bath water level caused by adding additional hot water from a shower or faucet to the bath tub 20 or drawing hot water from the bath tub 20 when the bath is being removed.

[0069] However, in the hot water supply system 300 shown in Figure 1, when there is a large difference in the placement height between the bathtub 20 and the water level sensor 11, if the temperature of the hot water between the bathtub 20 and the water level sensor 11 changes, a phenomenon may occur in which the water level detection value by the water level sensor 11 changes in response to this temperature change.

[0070] FIG. 6 shows a conceptual diagram illustrating the classification of bathtub placement heights.

[0071] Referring to Figure 6, if the placement height of the water level sensor 11 in the water heating apparatus 100 is taken as the reference height (H = 0), the placement height of the bathtub 20 can be defined as the height difference ΔH, which is the difference between the placement height of the circulation adapter 25 shown in Figure 1 and the reference height.

[0072] For example, as shown in FIG. 6, by comparing the height difference ΔH with predetermined boundary values ​​H1, -H2, the placement height of bathtub 20 relative to water heating apparatus 100 (water level sensor 11) placed outdoors on the ground can be stratified into "upper floor placement" corresponding to placement on the second floor or higher, "flat ground placement" corresponding to placement on the first floor, and "lower floor placement" corresponding to placement in the basement.

[0073] A conceptual diagram explaining the change in the detected water level value depending on the height at which the bathtub is placed is shown in Fig. 7. Fig. 7 shows the transition of the output voltage (i.e., the detected water level value) of water level sensor 11, which is made of a pressure sensor, when the temperature of the hot water retained between bathtub 20 (circulation adapter 25) and water level sensor 11 gradually decreases over time after the bath filling operation is completed.

[0074] 7, as the temperature Tbt of the stagnant hot water decreases over time, the density of the stagnant hot water gradually increases. In the case where bathtub 20 is placed at a position higher than water level sensor 11 (placed on an upper floor), the increase in density acts on water level sensor 11 as an increase in water pressure. Therefore, as shown by characteristic line L1, the water level detection value of water level sensor 11 gradually increases in response to the decrease in temperature.

[0075] In contrast, in cases where the bathtub 20 is placed lower than the water level sensor 11 (placed downstairs), the increase in density acts on the water level sensor 11 as a drop in water pressure. Therefore, as shown by characteristic line L2, the water level detection value of the water level sensor 11 gradually drops in response to a drop in temperature. On the other hand, in cases where the difference in height between the water level sensor 11 and the bathtub 20 is small (placed on flat ground), the phenomenon of the water level detection value of the water level sensor 11 rising or falling depending on the temperature of the stagnant hot water does not occur.

[0076] In this way, in the case of the upstairs and downstairs arrangements, there is a risk that the water level detection value by the water level sensor 11 will contain an error due to the change in the temperature of the hot and cold water. Therefore, in a configuration in which the reference water level Xref is updated to follow the change in the water level detection value when the bath is in the exiting state and not in operation, there is a concern that the reference water level Xref will contain an error due to the change in the temperature of the hot and cold water, making it impossible to accurately determine whether the bathing state is in or exiting.

[0077] A conceptual waveform diagram for explaining such concerns is shown in Fig. 8. Fig. 8 shows the waveform of the reference water level Xref (dashed line) together with the waveform of the water level detection value X in the case of the downstairs arrangement (solid line).

[0078] 8, the detected water level value X does not change in response to entering and leaving the bath, but temporarily sticks to the upper limit value Xmax due to the execution of the bath operation (reheating and circulating operation) between times t1 to t2 and t4 to t5. Furthermore, the detected water level value X changes in response to changes in the temperature of the hot and cold water between the bathtub 20 and the water level sensor 11.

[0079] Specifically, when the bathing operation ends at time t2, the controller 12 judges whether to enter or leave the bath based on the current water level detection value Xtn and the reference water level Xref. If the water level change amount ΔXtn from the reference water level Xref is less than the bathing judgment value ΔXin, the controller 12 maintains the judgment of the exit state.

[0080] After time t2, the temperature of the hot water accumulating between bathtub 20 and water level sensor 11 gradually decreases as time passes. In response to this decrease in temperature, the density of the accumulating hot water gradually increases. In the downstairs arrangement, as described above, the increase in density acts on water level sensor 11 as a decrease in water pressure, so that water level detection value X gradually decreases in response to the decrease in temperature.

[0081] When the bath is being removed and the bath is not in operation, the reference water level Xref is updated according to the detected water level value Xtx Tx seconds before the present. Therefore, after time t2, the reference water level Xref also gradually decreases in accordance with the decrease in the detected water level value X. In other words, the reference water level Xref includes an error caused by the change in the temperature of the hot and cold water.

[0082] When bath operation (reheating circulation operation) starts at time t4, updating of the reference water level Xref stops. The reference water level Xref at this time is the water level detection value Xtx at time t3, Tx (seconds) before time t4, when updating is stopped. During bath operation, the reference water level Xref is not updated, and is maintained at the water level detection value Xtx at time t3 before bath operation.

[0083] On the other hand, when bath water 21 is circulated and heated by the reheating circulation operation from time t4 to t5, the density of the hot water gradually decreases as the temperature of the hot water between bathtub 20 and water level sensor 11 gradually increases. In the downstairs arrangement, the decrease in density acts on water level sensor 11 as an increase in water pressure, so the detected water level value X increases in response to the increase in temperature. As a result, the detected water level value X at time t5 when the reheating circulation operation ends has increased from the detected water level value X at time t3 before the bath operation.

[0084] When the bath operation ends at time t5, the controller 12 judges whether the user has entered or left the bath based on the current water level detection value Xtn and the reference water level Xref (the water level detection value Xtx at time t3). If the amount of water level change ΔXtn from the reference water level Xref, which includes an error, is equal to or greater than the bathing judgment value ΔXin, it will be erroneously judged as a bathing state (time t6) since the condition ΔXtn≧ΔXin has continued for Tj1 (seconds). In other words, bathing will be erroneously detected.

[0085] Furthermore, even in the case of an upper floor arrangement, as in the case of a lower floor arrangement described above, there is a possibility of erroneous determination of the bathing state when determining whether to enter or exit the bath using the reference water level Xref, which contains errors due to changes in the temperature of the hot and cold water.

[0086] Furthermore, the phenomenon in which the water level detection value by the water level sensor 11 changes in response to temperature changes is not limited to the above-mentioned cases of upstairs and downstairs placement, but can also occur due to the temperature characteristics of the water level sensor 11, which is made up of a pressure sensor. If the output value of the water level sensor 11 contains an error due to changes in the ambient temperature of the water level sensor 11, it may erroneously determine the bathing state.

[0087] In order to address such concerns, in this embodiment, as described below, the reference water level Xref is corrected so that it reflects changes in the water level detection value due to changes in the temperature of hot and cold water during bath operation and changes in the ambient temperature of the water level sensor 11.

[0088] (Reference water level correction process) 9 and 10 are flow charts for explaining the correction process of the reference water level Xref according to the present embodiment. The control process of each step shown in Fig. 9 and 10 can be realized by the controller 12 executing a program stored in advance.

[0089] 9, in S01, controller 12 calculates placement height ΔH of bathtub 20. As shown in FIG 6, placement height ΔH of bathtub 20 can be defined as a height difference ΔH that is the difference between the placement height of water level sensor 11 in water heating apparatus 100, which is set as a reference height (H=0), and the placement height of circulation adapter 25.

[0090] The placement height ΔH of the bathtub 20 can be calculated by adjusting the off-voltage of the water level sensor 11 during the bathtub 20 filling operation. For example, it can be calculated by dividing the off-voltage adjustment amount Vref [mV] by the resolution [mV / mm] of the water level sensor 11. When placed on an upper floor, the placement height ΔH is a positive value (ΔH>0), and when placed on a lower floor, the placement height ΔH is a negative value (ΔH<0). Information indicating the placement height ΔH of the bathtub 20 can be obtained during the bath filling operation that is performed on a trial basis during the bath trial run. Alternatively, information indicating the placement height ΔH of the bathtub 20 can be obtained by the installer entering a code, etc. In this way, the placement height of the bathtub 20 can be obtained by any method.

[0091] The controller 12 detects the presence or absence of bath water in the bathtub 20 in S02. In S02, the presence or absence of bath water circulating in the circulation path 8 is detected. Specifically, when the circulation pump 10 is operated, a detection signal from a water flow switch (not shown) arranged on the circulation path 8 is input to the controller 12. The detection signal is turned on when there is a flow in the circulation path 8 exceeding a predetermined flow rate, and is turned off when there is no flow. When the bath water level is lower than a predetermined water level corresponding to the set water level of the circulation adapter 25, bath water is not introduced into the circulation path 8 even if the circulation pump 10 is operated, so the detection signal of the water flow switch is turned off. Therefore, when the detection signal is off, it is determined that there is no bath water in the bathtub 20. On the other hand, when the detection signal is on, it is determined that there is bath water in the bathtub 20.

[0092] If it is determined that bath water is present in the bathtub 20 (YES in S02), the controller 12 proceeds to S03 and determines whether or not the user is in a bathing state. If the user is not in a bathing state (NO in S03), the process returns to S02.

[0093] If it is determined in S03 that the bath is left in the bath withdrawal state (YES in S03), controller 12 determines in S04 whether water heating apparatus 100 is in the reheating circulation operation. If water heating apparatus 100 is performing the reheating operation in response to an instruction to perform the reheating operation by operating remote controls 30, 50, YES is determined in S03. On the other hand, if the reheating operation has not been instructed and the reheating operation is not being performed, NO is determined in S04 and the processes of S05 to S07 are skipped.

[0094] If the reheating circulation operation is in progress (YES in S04), the controller 12 determines in S05 whether the reheating circulation operation has ended. If it is determined that the reheating circulation operation has ended (YES in S05), the controller 12 acquires the water level detection value X0 by the water level sensor 11 at the time when the reheating circulation operation ended in S06.

[0095] In S07, the controller 12 updates the reference water level Xref by setting the water level detection value X0 acquired in S06 as the reference water level Xref, and stores the updated reference water level Xref. In S07, the reference water level Xref based on the water level detection value X0 at the end of the reheating circulation operation is stored as a "reference value."

[0096] In S08, controller 12 determines whether water heating apparatus 100 is in bath operation. As described above, bath operation includes circulation operation and hot water pouring operation. If water heating apparatus 100 is in bath operation (YES determination in S08), controller 12 proceeds to S09, and obtains and stores the current water level detection value Xtn. This allows the water level detection value at each point in time to be accumulated periodically each time the processes of S02 to S09 are executed.

[0097] In S10, the controller 12 reads out the water level detection value Xtx acquired Tx (seconds) before the present. At this time, by deleting some of the water level detection values ​​that have already been stored, it is possible to reduce the memory capacity used for bathing entry and exit determination.

[0098] In step S11, the controller 12 updates the reference water level Xref by setting the detected water level value Xtx read in step S10 as the reference water level Xref.

[0099] In S12, the controller 12 determines whether a bath operation has been commanded by operating the remote controls 30, 50. If a bath operation has not been commanded (NO in S12), the controller 12 returns to S02 and repeats the processes of S02 to S11. As a result, in the bath exit state, when the bath operation is not in progress, the reference water level Xref is periodically updated according to the water level detection value Xtx from Tx (seconds) before the present. In addition, each time the reheating circulation operation is performed, the reference water level Xref based on the water level detection value X0 at the end of the reheating circulation operation is stored as a reference value.

[0100] When the bath operation is instructed (YES in S12), the controller 12 proceeds to S13 and reads out the reference value stored in S07. The read-out reference value is equal to the water level detection value X0 obtained at the end of the reheating circulation operation.

[0101] In S14, the controller 12 calculates the difference (Xtn-X0) between the current water level detection value Xtx before the bath operation is performed and the reference value read out in S13, and compares the absolute value of the calculated difference (Xtn-X0) with a predetermined threshold value A.

[0102] When the absolute value of the difference (Xtn - X0) is smaller than the threshold value A at S14 (when the determination at S14 is NO), the controller 12 skips S15 to S17. At S18, the controller 12 obtains and stores the current temperature T1 [°C] of the bathtub water 21, which is before the execution of the bathtub operation, based on the detected value of the temperature sensor 9. The controller 12 further obtains and stores the ambient temperature F1 [°C] of the current water level sensor 11 based on the detected value of the temperature sensor 14.

[0103] At S19, the controller 12 executes the bathtub operation. When the bathtub operation is the post-combustion circulation operation, the bathtub water 21 is circulated and heated by the combustion of the heating mechanism of the post-combustion circuit 7. Therefore, during the bathtub operation, the temperature of the bathtub water 21 gradually rises. In response to this temperature rise, the density of the bathtub water 21 gradually decreases. Also, in the water supply device 100, the ambient temperature of the water level sensor 11 gradually rises with the combustion of the heating mechanism of the post-combustion circuit 7.

[0104] At S20, the controller 12 determines whether the bathtub operation has ended. At S20, based on the operations of the remote controllers 30 and 50 and / or the detected values of various sensors (such as a flow rate sensor (not shown) provided in the pouring pipe 13a and the temperature sensor 9), it is determined whether the bathtub operation has ended.

[0105] When it is determined that the bathtub operation has ended (when the determination at S20 is YES), the controller 12 proceeds to S21 and obtains and stores the current temperature T2 [°C] of the bathtub water 21, which is after the execution of the bathtub operation, based on the detected value of the temperature sensor 9. The controller 12 further obtains and stores the ambient temperature F2 [°C] of the current water level sensor 11 based on the detected value of the temperature sensor 14. When the bathtub operation at S19 is the post-combustion circulation operation, in response to the temperature rise of the bathtub water 21 during the bathtub operation, the relationship T1 < T2 holds for the temperature of the bathtub water 21. Also, the relationship F1 < F2 holds for the ambient temperature of the water level sensor 11.

[0106] In S22, the controller 12 calculates the amount of change ΔXc in the detected water level value caused by changes in the temperature of the bathtub water 21 and the ambient temperature of the water level sensor 11 during the bathing operation. As shown in FIG. 8, in the downstairs arrangement, the water level detected by the water level sensor 11 increases as the density of the bathtub water 21 decreases due to an increase in the temperature of the bathtub water 21. Therefore, the water level detected after the bathing operation is performed is higher than the water level detected before the bathing operation, and the amount of change ΔXc in the detected water level value is a positive value. Conversely, in the upstairs arrangement, the water level detected by the water level sensor 11 decreases as the density of the bathtub water 21 decreases. Therefore, the water level detected after the bathing operation is performed is lower than the water level detected before the bathing operation, and the amount of change ΔXc in the detected water level value is a negative value.

[0107] FIG. 11 is a flowchart for explaining the processing procedure of S22 in FIG.

[0108] 11, the controller 12 first calculates in S220 the temperature T [°C] of the bath water 21 obtained in S18 and S21 in relation to the density ρ [kg / m of the bath water 21 using the relationship between the temperature of the bath water and the density of the bath water previously obtained (see graph 410 in the figure). 3 ] is converted.

[0109] As shown in graph 410, bath water has the characteristic that, in a temperature range above a certain temperature (approximately 4°C), the density of the bath water decreases as the temperature increases. By referring to graph 410, controller 12 converts the temperature T1 [°C] of bath water 21 before the bathing operation, acquired in S18, into the density ρ1 [kg / m 3 ], and convert the temperature T2 [℃] of the bath water 21 after the bathing action acquired in S21 into density ρ2 [kg / m 3 ] is converted.

[0110] Next, in S222, the controller 12 converts the ambient temperature F [°C] of the water level sensor 11 acquired in S18 and S21 into the output displacement V [mm] of the water level sensor 11 using the temperature characteristics of the water level sensor 11 previously acquired (see graph 410 in the figure).

[0111] Graph 410 is an example of the temperature characteristics of the water level sensor 11, and shows the relationship between the deviation of the output value from the output value at the reference temperature Fref (hereinafter also referred to as "output displacement amount") and the ambient temperature of the water level sensor 11. The output displacement amount changes depending on the ambient temperature. In graph 410, the output displacement amount increases as the ambient temperature increases. In contrast to graph 410, some water level sensors have temperature characteristics in which the output displacement amount decreases as the ambient temperature increases. Alternatively, some water level sensors have temperature characteristics in which the output displacement amount increases as the temperature difference from the reference temperature Fref increases.

[0112] By referring to graph 410, the controller 12 converts the ambient temperature F1 [°C] before the bath operation obtained in S18 into an output change amount V1 [mm], and converts the ambient temperature F2 [°C] after the bath operation obtained in S21 into an output change amount V2 [mm].

[0113] Finally, in S224, the controller 12 calculates the amount of change ΔXc in the water level detection value by the water level sensor 11 caused by the temperature change during the bath operation. The amount of change ΔXc in the water level detection value can be obtained using the following formula (1). ΔXc=k[(ρ2-ρ1)×ΔH×g]±|V2−V1| …(1) Here, ΔH is the height of the bathtub 20 ΔH [m], and g is the gravitational acceleration [m / g 2 ] and k is the conversion constant (unit: mm / Pa) for converting water pressure [Pa] to water level [mm].

[0114] In equation (1), the first term on the right side corresponds to the amount of change (first amount of change) in the detected water level value that depends on the temperature change of the hot and cold water, which is caused by the height ΔH of bathtub 20. The second term on the right side corresponds to the amount of change (second amount of change) in the detected water level value that is caused by the temperature characteristics of water level sensor 11. The sign "±" added to the second term is determined by the temperature characteristics of water level sensor 11. If water level sensor 11 has temperature characteristics in which the output displacement amount increases with an increase in ambient temperature, as in graph 410, the sign "-" is added to the second term to offset the output displacement amount. If water level sensor 11 has temperature characteristics in which the output displacement amount decreases with an increase in ambient temperature, the sign "+" is added to the second term to offset the output displacement amount.

[0115] Returning to Fig. 10, in S23, the controller 12 corrects the reference water level Xref by adding the amount of water level change ΔXc calculated in S22 to the reference water level Xref. The reference water level Xref before correction is equal to the detected water level value obtained before the bath operation is performed, and updating has been stopped in response to the bath operation command (S12). By adding the amount of water level change ΔXc calculated based on the temperature change of the hot and cold water during the bath operation and the change in the ambient temperature of the water level sensor 11 to this reference water level Xref, the change in the detected water level value caused by the temperature change during the bath operation can be reflected in the reference water level Xref.

[0116] If the bath operation in S19 is a pouring operation, in S23, the controller 12 further adds the rise in the bathtub water level due to the pouring operation, ΔXd, to the reference water level Xref, thereby allowing the rise in the water level detection value due to the pouring operation to be reflected in the reference water level Xref. Specifically, during the pouring operation, the controller 12 calculates the amount of poured water by integrating the detection value of a flow rate sensor (not shown) provided in the pouring pipe 13a. The rise in the bathtub water level, ΔXd, can be obtained by dividing this calculated amount of poured water by the cross-sectional area of ​​the bathtub 20.

[0117] Returning to S14, if it is determined that the absolute value of the difference (Xtn-X0) between the current water level detection value Xtn before the bath operation is performed and the reference value X0 read out in S13 is equal to or greater than threshold value A (YES in S14), the controller 12 proceeds to S15 and executes non-combustion circulation operation for a predetermined period of time. The non-combustion circulation operation of S15 is executed to equalize the temperature of the hot and cold water accumulating in the circulation path 8 as a preprocessing step for correcting the reference water level Xref, as described below.

[0118] As time passes from the end of the reheating circulation operation, a temperature distribution may occur in the stagnant hot water due to a drop in the temperature of the hot water stagnating between the bathtub 20 and the water level sensor 11. This is because the density of the stagnant hot water increases as the temperature of the stagnant hot water drops, resulting in a temperature distribution in the circulation path 8 according to the height ΔH of the bathtub 20 when the bathtub is placed upstairs or downstairs.

[0119] The temperature distribution of the stagnant hot water creates a temperature difference between the temperature of bathtub water 21 detected by temperature sensor 9 and the actual temperature of bathtub water 21. Therefore, the temperature T1 [°C] of bathtub water 21 acquired in S18 before the bath operation is performed based on the detection value of temperature sensor 9 will include this temperature difference, making it impossible to accurately detect the temperature change of bathtub water 21 during the bath operation, and as a result, it may not be possible to accurately calculate the change in the water level detection value caused by this temperature change.

[0120] Therefore, when a bath operation is instructed (YES judgement in S12), if it is judged that the absolute value of the difference (Xtn-X0) between the current water level detection value Xtn and the reference value based on the water level detection value X0 at the end of the reheating circulation operation is equal to or greater than threshold A (YES judgement in S14), it is judged that there may be a temperature distribution in the stagnant hot water between the bathtub 20 and the water level sensor 11, and a non-combustion circulation operation is performed for a predetermined time (S15) prior to performing the bath operation in S19. This circulates the stagnant hot water in the circulation path 8 to equalize the temperature of the stagnant hot water. The predetermined time can be set according to the circulation flow rate in the circulation path 8 so that the stagnant hot water can circulate at least once around the circulation path 8 by the non-combustion circulation operation.

[0121] In this way, by configuring the system to perform non-combustion circulation operation when the absolute value of the difference (Xtn-X0) between the current water level detection value Xtn and the reference value based on the water level detection value X0 at the end of the reheating circulation operation is greater than or equal to the threshold value A, it is possible to prevent unnecessary non-combustion circulation operation from being performed when the temperature drop of the stagnant hot water is small and the temperature distribution is narrow.

[0122] When the non-combustion circulation operation in S15 ends, the controller 12 judges in S16 whether or not the user is in the leaving-bathing state based on the reference water level Xref and the current water level detection value Xtn. In S16, the water level change amount ΔXtn from the reference water level Xref is calculated by subtracting the reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref), and the calculated water level change amount ΔXtn is compared with the bathing judgment value ΔXin. If the water level change amount ΔXtn remains equal to or greater than the bathing judgment value ΔXin for Tj1 (seconds), the user is judged to be in the bathing state. If the water level change amount ΔXtn does not remain equal to or greater than the bathing judgment value ΔXin for Tj1 (seconds), the user is judged to be in the leaving-bathing state.

[0123] The bathing entry / exit determination in S16 may be combined with a determination of the presence or absence of a person in bathroom 200 using a human presence sensor (not shown) installed in bathroom 200. If it is determined that a person is present in bathroom 200 and the state in which the amount of water level change ΔXtn is equal to or greater than the bathing determination value ΔXin continues for Tj1 (seconds), it can be determined that the person is in the bathing state.

[0124] If it is determined in S16 that the user is in the bathing state (YES in S16), the controller 12 updates the reference water level Xref by setting the current water level detection value Xtn to the reference water level Xref in S17. That is, the water level detection value in a state where the temperature distribution of stagnant hot water has been eliminated is set to the reference water level Xref. On the other hand, if it is determined in S16 that the user is in the bathing state (NO in S16), the controller 12 skips S17.

[0125] The controller 12 then executes the processes of S18 to S23 to perform the bath operation, and after the bath operation, calculates the change in the water level detection value ΔXc based on the temperature of the bathtub water 21 and the ambient temperature of the water level sensor 11 obtained before and after the bath operation, respectively, and corrects the reference water level Xref using the calculated change in the water level detection value ΔXc.

[0126] (Example) In the following, the process of correcting the reference water level according to this embodiment and the process of determining whether to enter or exit the bath using the reference water level will be described with reference to examples.

[0127] Fig. 12 is a conceptual waveform diagram for explaining a first example of correction of the reference water level and bathing entry / exit determination according to this embodiment, and is a diagram to be compared with Fig. 8. Fig. 12 shows the waveform of the reference water level Xref (dashed line) together with the waveform of the water level detection value X in the case of downstairs placement (solid line).

[0128] 12, as in Fig. 8, the water level detection value X by the water level sensor 11 changes depending on the bath operation (reheating circulation operation) in the period from time t1 to t2 and the period from time t4 to t5, and the temperature change of the hot and cold water between the bathtub 20 and the water level sensor 11. In other words, the behavior of the water level detection value X shown in Fig. 12 is the same as that in Fig. 8.

[0129] In the example of Fig. 12, when the bath operation (reheating circulation operation) ends at time t2, the controller 12 judges whether the user is entering or leaving the bath based on the current water level detection value Xtn and the reference water level Xref, as in Fig. 8. If it is judged that the user is in the leaving state, the controller 12 stores the water level detection value X0 obtained at the end of the reheating circulation operation as a reference value for the reference water level Xref.

[0130] After time t2, the water level detection value X gradually decreases in response to the decrease in the temperature of the hot water stagnating between bathtub 20 and water level sensor 11, and the reference water level Xref also gradually decreases so as to follow the decrease in the water level detection value X.

[0131] When a bath operation (reheating circulation operation) is instructed at time tc, the controller 12 compares the absolute value of the difference (Xtn-X0) between the reference value X0 and the current water level detection value Xtn with the threshold value A. If the absolute value of the difference (Xtn-X0) is less than the threshold value A, the controller 12 acquires and stores the temperature T1 [°C] of the bath water 21 and the ambient temperature F1 [°C] of the water level sensor 11 before the bath operation is performed based on the detection values ​​of the temperature sensors 9 and 14. In the example of FIG. 12, the temperature T1 [°C] of the bath water 21 and the ambient temperature F1 [°C] of the water level sensor 11 at time t3, which is Tx (seconds) before time t4, the start of the bath operation, are stored. Furthermore, the controller 12 stops updating the reference water level Xref. The reference water level Xref at this time is the water level detection value Xtx at time t3.

[0132] When the bath operation ends at time t5, the controller 12 acquires and stores the temperature T2 [°C] of the bath water 21 after the bath operation and the ambient temperature F2 [°C] of the water level sensor 11 based on the detection values ​​of the temperature sensors 9 and 14.

[0133] Next, controller 12 substitutes the stored temperatures of bathtub water 21 and the ambient temperature of water level sensor 11 before and after the bath operation, and the height ΔH of bathtub 20 into equation (1) to calculate the amount of change ΔXc in the detected water level value caused by the change in temperature of the hot and cold water during the bath operation and the change in the ambient temperature of water level sensor 11. Controller 12 corrects reference water level Xref by adding the calculated amount of water level change ΔXc to the reference water level Xref (time t6).

[0134] The controller 12 judges whether to enter or leave the bath based on the corrected reference water level Xref and the current water level detection value Xtn. Specifically, the controller 12 calculates the amount of water level change ΔXtn from the reference water level Xref by subtracting the corrected reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref), and compares the calculated amount of water level change ΔXtn with the bathing judgment value ΔXin. If the amount of water level change ΔXtn does not remain equal to or greater than the bathing judgment value ΔXin for Tj1 (seconds), the controller 12 judges that the user is in the leaving state (time t7). When it is judged that the user is in the leaving state, updating of the reference water level Xref is resumed.

[0135] As shown in Figure 8, the water level detection value by the water level sensor 11 changes due to changes in the temperature of the hot and cold water during the bath operation and changes in the ambient temperature of the water level sensor 11. Therefore, if the reference water level Xref based on the water level detection value before the bath operation is used to determine whether the bathing state or the out-of-bath state is determined after the bath operation, it may be erroneously determined that the bathing state is being performed, resulting in a false detection of bathing.

[0136] In contrast, in this embodiment, the reference water level Xref is corrected after the bathing operation to reflect the change in the detected water level caused by the temperature change during the bathing operation, so that the change in the detected water level caused by the temperature change during the bathing operation can be removed from the amount of water level change ΔXtn from the reference water level Xref calculated after the bathing operation. This makes it possible to accurately determine whether the bathing state is in or out of the bath, thereby preventing erroneous detection of bathing.

[0137] Fig. 13 is a conceptual waveform diagram for explaining a second example of the correction of the reference water level and the determination of bathing entry and exit according to the present embodiment. Fig. 13 shows the waveform of the reference water level Xref (dashed line) together with the waveform of the water level detection value X in the case of the downstairs arrangement (solid line).

[0138] In Fig. 13, as in Fig. 12, the water level detection value X by water level sensor 11 changes due to the bath operation (reheating circulation operation) during the period from time t1 to t2 and the period from time t4 to t5, and due to the change in temperature of hot and cold water between bathtub 20 and water level sensor 11. However, it differs from Fig. 12 in that the actual water level rises in response to bathing at time ta during the period from time t4 to t5.

[0139] 12, during bath operation from time t4 onwards, the reference water level Xref is not updated and is maintained at the water level detection value Xtx at time t3. Then, when the bath operation (reheating circulation operation) ends at time t5, the change amount ΔXc in the water level detection value calculated based on the change in the temperature of the bathtub water 21 during bath operation and the ambient temperature of the water level sensor 11 is added to the reference water level Xref, correcting the reference water level Xref (time t6).

[0140] The controller 12 judges whether the user is in a bathing state or out of a bathing state based on the corrected reference water level Xref and the current water level detection value Xtn. Specifically, the controller 12 calculates the amount of water level change ΔXtn from the reference water level Xref by subtracting the corrected reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref), and compares the calculated amount of water level change ΔXtn with the bathing judgment value ΔXin.

[0141] If the state in which the water level change amount ΔXtn is equal to or greater than the bathing judgment value ΔXin continues for Tj1 (seconds), the controller 12 determines that the bathing state is present (time t7). When the bathing state is detected at time t7, the update of the reference water level Xref is continued to be suspended. Therefore, the reference water level Xref is maintained at the corrected reference water level Xref.

[0142] Fig. 14 is a conceptual waveform diagram for explaining a third example of correction of the reference water level and judgment of bathing entry and exit according to this embodiment, and is a diagram to be compared with Fig. 12. Fig. 14 shows the waveform of the reference water level Xref (dashed line) together with the waveform of the water level detection value X in the case of downstairs arrangement (solid line).

[0143] The behavior of the water level detection value X shown in Figure 14 differs from the behavior of the water level detection value X shown in Figure 12 in that the water level detection value X changes due to non-combustion circulation operation in the period from time t8 to t9 between bath operation (reheating circulation operation) in the period from time t1 to t2 and bath operation (reheating circulation operation) in the period from time t4 to t5.

[0144] 14, when bath operation (reheating circulation operation) is commanded at time tc, the controller 12 compares the absolute value of the difference (Xtn-X0) between the current water level detection value Xtn and the reference value X0 with the threshold value A. If the absolute value of the difference (Xtn-X0) is equal to or greater than the threshold value A, the controller 12 performs non-combustion circulation operation for a predetermined time, thereby equalizing the temperature of the hot and cold water in the circulation path 8.

[0145] Furthermore, the controller 12 stops updating the reference water level Xref. The reference water level Xref at this time is the water level detection value Xtx at time t3, which is Tx (seconds) before time t8, which is the start point of the non-combustion circulation operation.

[0146] When the non-combustion circulation operation ends at time t9, the controller 12 judges whether the bathing state is in or out of the bathing state based on the reference water level Xref and the current water level detection value Xtn. Specifically, the water level change amount ΔXtn from the reference water level Xref is calculated by subtracting the reference water level Xref from the current water level detection value Xtn (ΔXtn=Xtn-Xref), and the calculated water level change amount ΔXtn is compared with the bathing judgment value ΔXin. If the state in which the water level change amount ΔXtn is equal to or greater than the bathing judgment value ΔXin does not continue for Tj1 (seconds), it is judged to be in the out of the bathing state (time t10). This judgment can be combined with a judgment of the presence or absence of a person in the bathroom 200 using a human presence sensor provided in the bathroom 200.

[0147] If it is determined that the bath is being withdrawn, the controller 12 updates the reference water level Xref by setting the current water level detection value Xtn to the reference water level Xref (time t9).

[0148] Next, the controller 12 obtains and stores the temperature T1 [°C] of the bath water 21 and the ambient temperature F1 [°C] of the water level sensor 11 before the bathing operation is performed based on the detection values ​​of the temperature sensors 9 and 14, as in Fig. 12. In the example of Fig. 14, the temperature T1 [°C] of the bath water 21 and the ambient temperature F1 [°C] of the water level sensor 11 at time t9 when the reference water level Xref is updated are stored.

[0149] When the bathing operation ends at time t5, the controller 12 acquires and stores the temperature T2 [°C] of the bath water 21 and the ambient temperature F2 [°C] of the water level sensor 11 after the bathing operation based on the detection values ​​of the temperature sensors 9 and 14. The controller 12 calculates the amount of change ΔXc in the detected water level value caused by the change in the temperature of the water during the bathing operation and the change in the ambient temperature of the water level sensor 11 by substituting the stored temperatures of the bath water 21 and the ambient temperature of the water level sensor 11 before and after the bathing operation and the height ΔH of the bathtub 20 into formula (1), and corrects the reference water level Xref by adding the calculated amount of water level change ΔXc to the reference water level Xref (time t6). Bathing entry and exit are determined based on this corrected reference water level Xref and the current detected water level value Xtn.

[0150] As described above, the bath device according to this embodiment is configured to determine whether the user is in a bathing state or a leaving state based on the reference water level Xref, which is generated based on the water level detection value of the water level sensor 11 acquired when the user is in the leaving state and not in the bathing operation, and the water level detection value of the water level sensor 11 acquired after the bathing operation is performed, and the reference water level reflects changes in the water level detection value caused by changes in the temperature of the bath water during the bathing operation and changes in the ambient temperature of the water level sensor 11. With this configuration, changes in the water level detection value caused by temperature changes during the bathing operation can be removed from the amount of water level change ΔXtn from the reference water level Xref calculated after the bathing operation, making it possible to accurately determine whether the user is in a bathing state or a leaving state.

[0151] Furthermore, according to the above configuration, changes in the water level detection value, which depend on the height of the bathtub (specifically, the difference in height between the bathtub and the water level sensor) and the temperature characteristics of the water level sensor 11, are reflected in the reference water level Xref, making it possible to realize bathing entry / exit judgment that is not affected by the height of the bathtub and the temperature characteristics of the water level sensor 11.

[0152] (Other configuration examples) In the above embodiment, the change amount (first change amount) of the water level detection value caused by the temperature change of the bath water 21 during the bath operation and the change amount (second change amount) of the water level detection value caused by the change of the ambient temperature of the water level sensor 11 are calculated, and these change amounts are added together to calculate the change amount ΔXc of the water level detection value during the bath operation. However, the change amount ΔXc of the water level detection value during the bath operation can be calculated based on either the first change amount or the second change amount depending on the height of the bathtub and the temperature characteristics of the water level sensor 11. For example, when the bathtub 20 is placed on flat ground, the first change amount is small, so the change amount ΔXc of the water level detection value during the bath operation can be calculated based only on the second change amount. Also, when the water level sensor 11 does not have a temperature characteristic (or can be ignored), the change amount ΔXc of the water level detection value during the bath operation can be calculated based only on the first change amount.

[0153] 5, 9, 10, and 11 are described as being executed by controller 12, but the subject that executes the control process is not limited to this. For example, the control process can be executed by remote control 50 or a microcomputer (not shown) stored in 50, and the devices corresponding to the "control unit", "determination unit", and "generation unit" are not specified. The functions of the "control unit", "determination unit", and "generation unit" can also be realized by devices external to hot water supply system 300.

[0154] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0155] 8 Circulation path, 9, 14 Temperature sensors, 10 Circulation pump, 11 Water level sensor, 12 Controller, 20 Bathtub, 21 Bathtub water, 100 Water heater, 200 Bathroom, Xref Reference water level, ΔXin Bathing judgment value.

Claims

1. A bathing device including a bathtub, A water heater; A circulation path having a circulation pump for circulating hot and cold water in the bathtub between the hot water supply device and the bathtub; a water level detector that detects the water level in the bathtub based on the water pressure in the circulation path; A first temperature sensor for detecting the temperature of the hot and cold water; A control unit that controls the reheating circulation operation by operating the circulation pump; A determination unit that determines whether the bathtub is in a bathing state or in a leaving bathing state based on a water level detection value of the bathtub by the water level detector while the reheating circulation operation is stopped; a generating unit that generates a reference water level used in the determination unit to determine the bathing state and the leaving state, The generating unit periodically updates the reference water level according to the water level detection value a predetermined time before the present time while the bathing state is in the withdrawal state and the reheating circulation operation is stopped, while stopping the update of the reference water level while the bathing state or the reheating circulation operation is being performed; The generation unit further corrects the reference water level based on the amount of change in the temperature of the hot water before and after the execution of the reheating circulation operation calculated from the detection value of the first temperature sensor when the reheating circulation operation is completed, The judgment unit of the bath device judges that the bathing state is occurring when, after the reheating circulation operation is performed, the state in which the amount of increase in the current water level detection value relative to the corrected reference water level is equal to or greater than a predetermined judgment value continues for more than a predetermined first time.

2. The bath device of claim 1, wherein the generation unit calculates the amount of change in the water level detection value during the reheating circulation operation using the amount of change in the density of the hot water calculated from the amount of change in the temperature of the hot water and the difference in elevation between the bathtub and the water level detector, and corrects the reference water level by adding the calculated amount of change in the water level detection value to the reference water level.

3. A second temperature sensor is provided for detecting an ambient temperature of the water level detector. A bath device as described in claim 1, wherein when the reheating circulation operation is completed, the generation unit corrects the reference water level based on the amount of change in the hot water temperature before and after the reheating circulation operation is performed calculated from the detection value of the first temperature sensor, and the amount of change in the ambient temperature before and after the reheating circulation operation is performed calculated from the detection value of the second temperature sensor.

4. The bath device of claim 3, wherein the generation unit calculates a first amount of change in the water level detection value during the reheating circulation operation using the amount of change in the density of the hot water calculated from the amount of change in the temperature of the hot water and the difference in elevation between the bathtub and the water level detector, and calculates a second amount of change in the water level detection value during the reheating circulation operation using the amount of change in the ambient temperature, and corrects the reference water level by adding the calculated first and second amounts of change to the reference water level.

5. The generation unit is configured to store the water level detection value at the end of the reheating circulation operation as a reference value of the reference water level, A bath device as described in any one of claims 1 to 4, wherein the control unit performs a non-combustion circulation operation that does not involve combustion of the heating mechanism in the water heater at a predetermined second time before performing the reheating circulation operation when the difference between the water level detection value at the time when the reheating circulation operation is instructed and the reference value stored at the end of the previous reheating circulation operation is greater than or equal to a threshold value.

6. The bath device of claim 5, wherein the generation unit updates the reference water level according to the water level detection value at the end of the non-combustion circulation operation when it is determined that the bath is being removed after the non-combustion circulation operation is performed.

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