flush toilet

Abstract

To provide a technique capable of avoiding a situation in which washing water overflows from a bowl while washing the bowl when a water level in the bowl is high.SOLUTION: A flush toilet bowl comprises: a toilet bowl body having a bowl; and a supply part for supplying a first volume of washing water to the bowl. The supply part may reduce the amount of the washing water supplied to the bowl to a second amount of the washing water that is less than the first amount of the washing water in a particular case where a washing water level in the bowl reaches a second threshold value or less which is less than or equal to a first threshold value after the washing water level in the bowl is greater than or equal to the first threshold value.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a flush toilet. [Background technology]

[0002] Patent Document 1 discloses a system that uses a capacitance sensor to prevent toilet overflow. In Patent Document 1, the system detects toilet overflow by detecting the capacitance between two conductive plates attached to the outer surface of the outer wall of the toilet bowl body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-525690 Summary of the Invention [Problem to be solved by the invention]

[0004] If flush water is newly supplied to the bowl when the flush water level in the bowl placed in the toilet body is high, the water in the bowl may overflow. On the other hand, if flush water is not supplied to the bowl when the bowl needs to be flushed, dirt in the bowl will not be cleaned.

[0005] This specification provides a technique that can prevent wash water from overflowing from the bowl while washing the bowl when the water level in the bowl is high. [Means for solving the problem]

[0006] The technology disclosed in this specification relates to a flush toilet. The flush toilet includes a toilet body having a bowl and a supply unit that supplies a first volume of flush water to the bowl, and the supply unit may reduce the volume of the flush water supplied to the bowl to a second volume that is less than the first volume when the water level in the bowl reaches or exceeds a first threshold and then reaches or falls to or below a second threshold that is less than the first threshold.

[0007] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows a side view of a flush toilet according to an embodiment. [Figure 2] 1 shows a rear perspective view of a flush toilet according to an embodiment. [Figure 3] 1 is a cross-sectional view of the toilet device of the embodiment taken at the center in the left-right direction. [Figure 4] 4 shows a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] 5 shows an enlarged view of the area surrounded by the dashed line V in FIG. [Figure 6] 6 shows a cross-sectional view taken along line VI-VI in FIG. [Figure 7] An enlarged view of the area surrounded by dashed line VII in FIG. 6 is shown. [Figure 8] FIG. 1 is a block diagram showing a schematic configuration of a water level detection device. [Figure 9] 1 shows a flowchart of a water level detection process. [Figure 10] 1 shows a flowchart of a cleaning process. [Figure 11] 10 shows a flowchart of a water level detection process according to a second embodiment.

[0009] (Embodiment) (Outline of the configuration of the flush toilet 100: Figures 1 and 2) The flush toilet 100 is a so-called wall-hung toilet that is fixed to a wall 9. The flush toilet 100 comprises a toilet apparatus 6, a tank 2, a water level detection device 10, a control device 40, and an operating device 80. The toilet apparatus 6 comprises a toilet body 6m, a toilet seat 6s, a toilet lid 6c, a flush pipe 4, and a drain pipe 8.

[0010] Hereinafter, the direction in which the tank 2 and toilet device 6 are lined up will be referred to as the front-to-rear direction. In the front-to-rear direction, the side on which the toilet device 6 is arranged relative to the tank 2 will be referred to as the front side in the front-to-rear direction, and the side on which the tank 2 is arranged relative to the wall 9 will be referred to as the rear side in the front-to-rear direction. The horizontal direction perpendicular to the front-to-rear direction will be referred to as the left-to-right direction. In the left-to-right direction, the back side of the paper in FIG. 1 will be referred to as the right side, and the front side of the paper in FIG. 1 will be referred to as the left side. The vertical direction perpendicular to the front-to-rear direction will be referred to as the up-to-down direction. In the up-to-down direction, the side on which the tank 2 is arranged relative to the flush pipe 4 will be referred to as the upper side, and the side on which the flush pipe 4 is arranged relative to the tank 2 will be referred to as the lower side.

[0011] The toilet body 6m is made of ceramic. The toilet body 6m is equipped with a bowl 6b that receives waste. The tank 2 stores flush water for flushing the bowl 6b. The toilet seat 6s and toilet lid 6c are each connected to the toilet body 6m in an openable and closable manner. A drain pipe 8 connects the bowl 6b to a sewer pipe (not shown). The flush water in the bowl 6b is drained into the sewer pipe via the drain pipe 8. Note that the toilet seat 6s and toilet lid 6c are not shown in Figure 2. The tank 2, flush pipe 4, and water level detection device 10 are separated from the space in which the toilet apparatus 6 is placed by a wall 9. The user cannot see the part of the water level detection device 10 that is located outside the toilet apparatus 6. This improves the design of the flush toilet 100. It is possible to prevent the tank 2, flush pipe 4, and water level detection device 10 from being accidentally damaged or soiled during cleaning, etc.

[0012] The flush pipe 4 extends downward from the underside of the tank 2, bends, and extends forward to connect with the toilet body 6m. Flush water stored in the tank 2 is supplied to the toilet body 6m via the flush pipe 4. A water supply pipe 3s is connected to the upper back surface of the tank 2. The water supply pipe 3s extends downward from the tank 2, bends, and extends upward. A water supply solenoid valve 3 is located at the end of the water supply pipe 3s opposite the tank 2. As shown in Figure 2, the water supply solenoid valve 3 is connected to a clean water pipe 5 via a filter-equipped stop valve 3f. Water is pumped from a water source (not shown) to the clean water pipe 5. The water supply solenoid valve 3 takes in clean water via the filter-equipped stop valve 3f, preventing the intrusion of foreign matter. The water supply solenoid valve 3 is always open except when an abnormality occurs in the toilet device 6. A ball tap (not shown) is located inside the tank 2. The ball tap is equipped with a float ball (not shown) that displaces up and down depending on the level of flush water in the tank 2. When the level of flush water in the tank 2 rises to a predetermined level, the float ball rises, closing the ball tap. This stops the supply of clean water into the tank 2. Flush water in the tank 2 is supplied to the toilet device 6, and when the water level in the tank 2 drops, the float ball drops and the ball tap opens. As a result, clean water is supplied into the tank 2 from the water supply pipe 3s.

[0013] (Internal structure of the toilet device 6: Figures 3 and 4) The internal structure of the toilet apparatus 6 will be described with reference to Figures 3 and 4. The toilet seat 6s, toilet lid 6c, and drain pipe 8 are not shown in Figure 3. The toilet body 6m is provided with a rim water passage 20 and a storage space 30. The rim water passage 20 is a space that communicates with the flush pipe 4. Flush water in the tank 2 is supplied to the rim water passage 20 via the flush pipe 4.

[0014] As shown in FIG. 4, the rim water passage 20 includes a rear water passage 21, a left water passage 22, and a right water passage 24. The rear water passage 21 is located at the upper end of the bowl 6b, rear of the bowl 6b. The rim water passage 20 extends forward from the rear water passage 21 and branches into the left water passage 22 and the right water passage 24 along the upper edge of the bowl 6b. Flush water in the tank 2 flows from the flush pipe 4 into the rim water passage 20. In the rim water passage 20, the flush water flows forward from the rear water passage 21, branches into each of the water passages 22, 24, and is sent into the bowl 6b. The flush water flows along the inner surface of the bowl 6b. As a result, the inner surface of the bowl 6b is cleaned.

[0015] As shown in Figure 3, a through-hole 32 is provided in the upper wall located above the rear water passage 21. The through-hole 32 connects the rim water passage 20 and the storage space 30 above the rear water passage 21. An air vent (not shown) is provided in the part of the toilet body 6m that defines the upper end of the storage space 30. If a drainage abnormality occurs and flush water in the bowl 6b is not discharged normally, the flush water level in the rim water passage 20 will rise. If the flush water level exceeds the through-hole 32, the flush water will push the air in the storage space 30 through the through-hole 32. The air in the storage space 30 is released out of the storage space 30 through the air vent valve. As a result, flush water flows into the storage space 30. The flush water in the storage space 30 is temporarily stored.

[0016] The control device 40 is disposed behind the tank 2. The control device 40 controls the flush toilet 100. The control device 40 is equipped with a CPU (abbreviation for Central Processing Unit), which is a hardware processor, and memories such as RAM (abbreviation for Random Access Memory) and ROM (abbreviation for Read Only Memory). The control device 40 can execute processes in response to operations of the operating device 80 by the user.

[0017] The operating device 80 is attached to a wall. The operating device 80 is connected to the control device 40 so that it can communicate with the control device 40. The operating device 80 has a plurality of buttons 82 that can be operated by a user. The plurality of buttons 82 include a plurality of flush buttons. The flush button is a button for supplying flush water to the bowl 6b. The plurality of flush buttons include a large flush button and a small flush button. When the operating device 80 receives operation of any of the plurality of flush buttons, it transmits a flush instruction signal to the control device 40 according to the flush instruction signal that corresponds to the operated flush button. The control device 40 supplies flush water to the bowl 6b in accordance with the flush instruction signal received from the operating device 80.

[0018] When one of the multiple flush buttons is operated, the control device 40 causes flush water to be supplied to the bowl 6b via the flush pipe 4. The control device 40 selectively supplies one of two volumes of flush water, V1 or V2, to the bowl 6b. When the control device 40 receives a flush instruction signal corresponding to the large flush button, the control device 40 opens a flapper valve (not shown) located on the bottom of the tank 2 using a motor drive device built into the inside of the tank 2, thereby opening the tank 2. As a result, the flush water in the tank 2 is supplied to the bowl 6b. As the level of flush water stored in the tank 2 drops, the ball tap opens and clean water is supplied into the tank 2. While the flapper valve is open, the clean water supplied to the tank 2 is supplied to the bowl 6b. As the water level in the tank 2 drops, the flapper valve is closed. As a result, a large flush is performed in which flush water of volume V1 is supplied to the bowl 6b.

[0019] When controller 40 receives a flush command signal corresponding to the small-flush button, it opens the flapper valve in tank 2, supplying some of the flush water stored in tank 2 to bowl 6b. This executes a small-flush, in which flush water is supplied to bowl 6b at volume V2, which is less than volume V1. The flapper valve is open for a longer period during a large-flush than during a small-flush.

[0020] (Configuration of water level detection device 10: Figures 2 and 8) The configuration of the water level detection device 10 will be described with reference to Figures 2 and 8. As shown in Figure 2, the water level detection device 10 includes a pump 50, an air solenoid valve 52, a pressure sensor 11, a purge pipe 12, a first detection pipe 13, a second detection pipe 14, an air tank 15, a joint 16, and a three-way joint 17. The pump 50, the air solenoid valve 52, and the pressure sensor 11, together with the control device 40, are housed in a box installed on the back of the tank 2. Note that the actual box is covered from the rear with a cover, but the cover is not shown in Figures 2 and 8.

[0021] The first detection pipe 13 and the second detection pipe 14 each have a hollow tubular shape. The first detection pipe 13 and the second detection pipe 14 are made of resin. The tip portion of the second detection pipe 14 is disposed in the rim water passage 20. The second detection pipe 14 passes through the flush pipe 4 and extends to the rear of the toilet device 6. The end of the second detection pipe 14 opposite the rim water passage 20 is connected to the first detection pipe 13 via a three-way joint 17.

[0022] The first detection pipe 13 connects the three-way joint 17 and the pressure sensor 11. An air tank 15 is disposed in the first detection pipe 13 between the pressure sensor 11 and the three-way joint 17. The air tank 15 is filled with compressed air. The three-way joint 17 is connected to a purge pipe 12. The purge pipe 12 is connected to a pump 50 via an air solenoid valve 52.

[0023] The pressure sensor 11 is a sensor that detects the pressure inside the first detection tube 13. The pressure sensor 11 is a so-called strain gauge type pressure sensor. The pressure sensor 11 has a strain gauge resistor (not shown) inside. The displacement of the strain gauge resistor changes depending on the magnitude of the pressure inside the first detection tube 13. As a result, the resistance value of the strain gauge resistor changes. The pressure sensor 11 detects the pressure inside the first detection tube 13 based on the resistance value. Note that the pressure sensor 11 is not limited to the strain gauge type, and in a modified example, it may be a metal gauge type. In a further modified example, the pressure sensor 11 may be a semiconductor gauge type or a semiconductor diaphragm type, or may be at least one of a quartz pressure sensor and a capacitance bridge type sensor.

[0024] First detection pipe 13 is connected to bowl 6b via second detection pipe 14. When the water level in bowl 6b rises, the tip of second detection pipe 14 is blocked, causing the pressure inside second detection pipe 14 to rise. As the pressure inside second detection pipe 14 rises, the pressure inside first detection pipe 13 also rises. For this reason, the detection value of pressure sensor 11 fluctuates according to the water level in bowl 6b.

[0025] As shown by the dashed lines in FIG. 8 , the control device 40 is further communicatively connected to the water supply solenoid valve 3, the pressure sensor 11, the pump 50, and the air solenoid valve 52. The control device 40 controls the water supply solenoid valve 3, the pressure sensor 11, the pump 50, and the air solenoid valve 52. The control device 40 is communicatively connected to a management terminal 60. The management terminal 60 is a terminal operated by the manager of the flush toilet 100, and is located, for example, at the management company of the building in which the flush toilet 100 is installed. The control device 40 transmits the usage status and drainage status of the flush toilet 100 to the management terminal 60. The manager of the flush toilet 100 uses the management terminal 60 to remotely operate the flush toilet 100. In a modified example, the management terminal 60 may be at least one of a mobile terminal and a PC owned by at least one of the user of the flush toilet 100 and the cleaning company.

[0026] (Detailed structure of the second detector tube 14: Figures 3 to 7) As shown in Figure 3, the second detection pipe 14 passes through the outer wall of the flush pipe 4 via a joint 16 and extends forward. The second detection pipe 14 has an internal portion 14b that is positioned inside the toilet apparatus 6, and an external portion 14a that is positioned outside the toilet apparatus 6. The internal portion 14b of the second detection pipe 14 passes inside the flush pipe 4 and is positioned in the rim water passage 20 of the toilet body 6m.

[0027] By passing the second detection pipe 14 through the flush pipe 4 connected to the back of the toilet body 6m, each component of the water level detection device 10, including the external device portion 14a (i.e., the control device 40, pump 50, air solenoid valve 52, pressure sensor 11, purge pipe 12, first detection pipe 13, air tank 15, joint 16, and three-way joint 17), can be positioned away from the user. As a result, each component of the water level detection device 10 can be prevented from coming into contact with the user. In particular, the occurrence of at least one of displacement and damage to the second detection pipe 14 can be suppressed. Each component of the water level detection device 10 can be made less visible to the user. As a result, the design of the flush toilet 100 can be improved.

[0028] As shown in FIG. 4, the internal device section 14b bends to the left (i.e., downward in the plane of FIG. 4) at the rear water passage 21 and extends down the left water passage 22. The tip section 14c of the internal device section 14b is located within the left water passage 22. An opening is provided in the end face 18 of the tip section 14c, which connects the internal device section 14b to the left water passage 22. The second detection pipe 14 connects the left water passage 22 to the pressure sensor 11 (see FIG. 1) via the first detection pipe 13. If a drainage abnormality occurs and the flush water level rises to the left water passage 22, the opening in the end face 18 of the second detection pipe 14 is blocked by the flush water. As a result, the pressure in the second detection pipe 14 rises. The pressure in the second detection pipe 14 is detected by the pressure sensor 11 via the first detection pipe 13.

[0029] The higher the flush water level in bowl 6b, the greater the amount of flush water located above end surface 18. The higher the flush water level in bowl 6b, the greater the pressure in second detection pipe 14 and first detection pipe 13. In other words, the flush water level in bowl 6b correlates with the pressure in second detection pipe 14 and first detection pipe 13. For this reason, water level detection device 10 can detect the water level in bowl 6b by detecting the pressure in second detection pipe 14 and first detection pipe 13.

[0030] Because the internal device portion 14b is disposed within the rim water passage 20, it is covered by the outer wall of the toilet body 6m that defines the rim water passage 20. This prevents dirt from adhering to the internal device portion 14b. For example, when cleaning the bowl 6b, it is possible to prevent the tip portion 14c from coming into contact with a cleaning tool, thereby preventing at least one of displacement and damage to the tip portion 14c.

[0031] As shown in Figure 6, each water passage 22, 24 branches out and extends to the left and right sides of the upper edge of bowl 6b. As shown in Figure 7, end face 18 of second detection pipe 14 abuts against bottom surface 28 of left water passage 22. As a result, when the flush water level reaches bottom surface 28 of left water passage 22, the opening of end face 18 of second detection pipe 14 is blocked by the flush water. This allows control device 40 to detect the water level in bowl 6b at a relatively early stage after the flush water level starts to rise.

[0032] (Purge process: Figure 8) When flush water is supplied to bowl 6b, the flush water passes through left water passage 22 while mixing with air in the flush water passage. The large pressure changes that occur when flush water is supplied to bowl 6b can cause flush water to enter the inner circumferential surface of tip portion 14c, creating multiple layers of water and air. As a result, flush water that has entered second detection pipe 14 can form a water film 72 that blocks second detection pipe 14. If second detection pipe 14 is blocked by water film 72, pressure may not be transmitted even though the water level in bowl 6b has reached second detection pipe 14. In this case, control device 40 cannot accurately detect the flush water level in bowl 6b using the pressure value detected by pressure sensor 11.

[0033] The second detection pipe 14 is connected to the purge pipe 12 via a three-way joint 17. The purge pipe 12 is connected to the pump 50 via an air solenoid valve 52 and an air pipe 54. The control device 40 operates the pump 50 and simultaneously opens the air solenoid valve 52. This causes air 70 to be pumped into the second detection pipe 14 via the purge pipe 12 and the three-way joint 17. The air 70 pushes a water film 72 and an air layer inside the second detection pipe 14 into the left water passage 22. After a predetermined time has elapsed, the control device 40 simultaneously stops the operation of the pump 50 and closes the air solenoid valve 52. This prevents the formation of the water film 72 inside the second detection pipe 14. As a result, the water film 72 and the air layer inside the second detection pipe 14 are prevented from affecting the detected pressure. The air solenoid valve 52 may be replaced with a check valve.

[0034] (Water level detection processing) When the flush toilet 100 is installed, the control device 40 executes a water level detection process. In the water level detection process, the control device 40 detects the pressure inside the first detection pipe 13 and the second detection pipe 14 (hereinafter referred to as the detected pressure) detected by the pressure sensor 11. A reference pressure Th1 is stored in the control device 40. In the water level detection process, the control device 40 monitors whether the detected pressure exceeds the reference pressure Th1 in a normal state in which flush water is not being supplied.

[0035] Reference pressure Th1 is set to a value that allows detection of a state in which the opening of second detection pipe 14 is blocked by water in bowl 6b by comparing it with the detected pressure. That is, control device 40 detects that the water level in bowl 6b has exceeded the water level corresponding to reference pressure Th1 by detecting that the detected pressure exceeds reference pressure Th1.

[0036] When the control device 40 receives a flush command signal from the operating device 80 after accepting operation of the flush button, the control device 40 detects that the water level in the bowl 6b exceeds a water level corresponding to the reference pressure Th4 by detecting that the detected pressure exceeds a reference pressure Th4 during a specific period from when the flush command signal is received until flush water is supplied and the flush water level in the bowl 6b stabilizes. The reference pressure Th4 is higher than the reference pressure Th1. While flush water is being supplied, the opening of the second detection pipe 14 is blocked by the flush water flowing through the rim water passage 20 and the temporary water level in the bowl 6b. The reference pressure Th4 is set taking into account the state in which the opening of the second detection pipe 14 is blocked by the flush water flowing through the rim water passage 20 and the temporary water level in the bowl 6b.

[0037] (Water level monitoring process: Figure 9) When the control device 40 detects that the detected pressure is equal to or greater than the reference pressure Th1, it executes a water level monitoring process. The control device 40 stores in advance a reference pressure Th2 and a pressure change threshold Th3 to be used in the water level monitoring process. The reference pressure Th2 is lower than the reference pressure Th1.

[0038] As shown in FIG. 9, in the water level monitoring process, in S10, the controller 40 sets a flush water prohibition flag that is pre-stored in the controller 40 to ON. When the flush water prohibition flag is set to ON, the controller 40 does not supply flush water to the bowl 6b even if the flush button is operated by the user. This causes the flush water level to rise, preventing the flush water from overflowing from the toilet body 6m. In S12, the controller 40 monitors the detected pressure until it reaches or falls below reference pressure Th2. If the detected pressure is below reference pressure Th2, the opening of second detection pipe 14 is blocked by flush water, but the water level is lower than when the detected pressure exceeds reference pressure Th1. If the detected pressure reaches or falls below reference pressure Th2 (YES in S12), in S14 the controller 40 sets a flush water control flag that is pre-stored in the controller 40 to ON and sets the flush water prohibition flag to OFF. Standard pressure Th2 is set so that flush water will not overflow from toilet body 6m even if flush water is supplied to bowl 6b during a small flush, as long as the water level corresponds to standard pressure Th2.

[0039] In S16, the control device 40 cumulatively records combinations of detected pressure and detection timing. In S18, the control device 40 calculates the change in detected pressure per unit time, for example, per second. In S20, the control device 40 determines whether the change in detected pressure calculated in S18 is equal to or greater than a pressure change threshold value Th3. Note that if only one combination of detected pressure and detection timing has been recorded, the processes of S18 and S20 are skipped.

[0040] If the change in detected pressure is greater than or equal to the pressure change threshold Th3 (YES in S20), proceed to S24. If the change in detected pressure is not greater than or equal to the pressure change threshold Th3 (NO in S20), in S22 the control device 40 determines whether a predetermined period TD (e.g., 5 minutes) has elapsed since the timing at which the detected pressure exceeding the reference pressure Th1 was detected. If the predetermined period TD has not elapsed since that timing (NO in S22), return to S16. If the predetermined period TD has elapsed since that timing (YES in S22), proceed to S24. In S24, the control device 40 switches off the flush water regulation flag that was switched on in S10, and ends the water level monitoring process.

[0041] (Cleaning process: Figure 10) When one of the flush buttons on the operating device 80 is operated, the control device 40 executes a flush process to supply flush water to the bowl 6b. In the flush process, in S30, the control device 40 monitors whether a flush instruction signal has been received from the operating device 80. When a flush instruction signal has been received (YES in S30), the control device 40 determines in S32 whether the flush water prohibition flag has been set to ON. If the flush water prohibition flag has been set to ON (YES in S32), the flush process ends. This prevents flush water from being supplied to the bowl 6b. The control device 40 may also output a message to the user indicating that flush water cannot be supplied.

[0042] If the flush water prohibition flag is set to OFF (NO in S32), the controller 40 determines in S34 whether the flush water restriction flag is set to ON. If the flush water restriction flag is set to OFF (NO in S34), the controller 40 supplies the amount of flush water specified in the flush instruction signal to the bowl 6b in S36, and ends the flush process.

[0043] If the flush water regulation flag is set to on (YES in S34), then in S38 the control device 40 supplies flush water of volume V2 to the bowl 6b. In S40, the control device 40 determines whether a clog has occurred while supplying flush water of volume V2. Specifically, the control device 40 detects that the detected pressure exceeds reference pressure Th4. If it detects that the detected pressure exceeds reference pressure Th4, then it is determined that a clog has occurred (YES in S40). If it does not detect that the detected pressure exceeds reference pressure Th4, then it is not determined that a clog has occurred (NO in S40). If it is NO in S40, then the flushing process ends.

[0044] If it is determined that a clog has occurred (YES in S40), in S42 the controller 40 reduces the amount of flush water supplied to bowl 6b from water volume V2 and ends the flush process. Specifically, the controller 40 closes electromagnetic control valve 3 to reduce the amount of flush water in tank 2, thereby suppressing the amount of flush water supplied to bowl 6b. In a modified example, the controller 40 may reduce the amount of flush water by forcibly closing a flapper valve in tank 2.

[0045] When clogging occurs, the amount of flush water supplied to bowl 6b can be reduced below water amount V2, thereby preventing flush water from overflowing from bowl 6b.

[0046] In the flushing process, even if the toilet device 6 is clogged and the water level is temporarily rising, the water level may fall, i.e., the flushing water Regulation When the flag is set to OFF, the amount of washing water intended by the user can be supplied to the bowl 6b, thereby allowing the bowl 6b to be washed appropriately.

[0047] During the flush process, if the water level in bowl 6b is high due to a drainage abnormality, and the large flush button is selected and flush water volume V1 should be supplied, flush water volume V2, which is less than volume V1, is supplied to prevent flush water from overflowing from bowl 6b and to flush bowl 6b. Volume V1 is the volume of water for a large flush, and volume V2 is the volume of water for a small flush. With this configuration, a conventional flush toilet 10 that performs flushes with two different volumes of water, a large flush and a small flush, can be controlled by the control device 40 to perform the water level detection process and flush process. In a modified example, the water volume may be reduced during a small flush by closing the water supply solenoid valve.

[0048] In the water level detection process, if it is detected that the detected pressure is equal to or greater than reference pressure Th1 and then equal to reference pressure Th2, that is, if it is detected that the water level in bowl 6b has risen to a level equal to or greater than reference pressure Th1 and then dropped to a level equal to or less than reference pressure Th2, the amount of flush water is reduced in the flush process.In other words, even if a drainage abnormality occurs due to a blockage, if the water is gradually drained, by supplying a smaller amount of flush water than usual, it is possible to flush the toilet body 6m while preventing flush water from overflowing.

[0049] When a predetermined period TD has elapsed since it was detected that the detected pressure was equal to or less than the reference pressure Th2, the flush water restriction flag is set to OFF. After the predetermined period TD has elapsed since it was detected that the detected pressure was equal to or less than the reference pressure Th2, it is highly likely that enough flush water has been drained into the bowl 6b to accommodate the volume V1 of flush water without overflowing. In other words, the predetermined period D is set to a period long enough to accommodate the volume V1 of flush water without overflowing. Alternatively, the drainage abnormality may have been resolved by the user before the predetermined period TD has elapsed. In the flush process, after the predetermined period TD has elapsed since it was detected that the detected pressure was equal to or less than the reference pressure Th2, a volume of flush water appropriate for the flush button selected by the user is supplied. This allows the bowl 6b to be properly flushed.

[0050] In the water level detection process, if the detected pressure drops below reference pressure Th2 and the change in pressure per unit time is equal to or greater than change threshold Th3, i.e., if the change in water level per unit time in bowl 6b corresponds to change threshold Th3, the flush water restriction flag is set to OFF. Even if a drainage abnormality occurs, if the water level drops quickly, bowl 6b can receive volume V1 of flush water without overflowing. In other words, change threshold Th3 is set so that it can be determined that the water level is dropping fast enough to receive volume V1 of flush water without overflowing. In the flush process, if the pressure change is equal to or less than change threshold Th3, a volume of flush water appropriate for the flush button selected by the user is supplied. This allows bowl 6b to be properly flushed.

[0051] (Correspondence) The control device 40 and the tank 2 are examples of a "supply unit." The reference pressure Th1 is an example of a "first threshold," the reference pressure Th2 is an example of a "second threshold," the reference pressure Th4 is an example of a "third threshold," and the change threshold Th3 is an example of a "fifth threshold." The water volume V1 is an example of a "first water volume," and the water volume V2 is an example of a "second water volume."

[0052] (Second embodiment) Differences from the first embodiment will be described. In this embodiment, the control device 40 executes the water level detection process shown in FIG. 11. In the water level detection process of this embodiment, the process in S222 differs from the process in S22. In S222, the control device 40 determines whether the detected pressure is equal to or less than the reference pressure Th5. The reference pressure Th5 is lower than the reference pressure Th2. For example, the reference pressure Th5 is atmospheric pressure. In S222, the control device 40 determines whether the water level in the bowl 6b has dropped to a level corresponding to the reference pressure Th5. If it is determined that the detected pressure is equal to or less than the reference pressure Th5 (YES in S222), that is, if it is determined that the water level in the bowl 6b has dropped to a level corresponding to the reference pressure Th5, the process proceeds to S24. If it is not determined that the detected pressure is equal to or less than the reference pressure Th5 (NO in S222), that is, if it is determined that the water level in the bowl 6b has not dropped to a level corresponding to the reference pressure Th5, the process returns to S16.

[0053] In the water level detection process, if the detected pressure drops below reference pressure Th2 and then falls below reference pressure Th5, i.e., if it is detected that the water level in bowl 6b is below the level corresponding to reference pressure Th5, the flush water restriction flag is set to OFF. Even if a drainage abnormality occurs, it may be subsequently resolved or alleviated. When the water level in bowl 6b is below the level corresponding to reference pressure Th5, bowl 6b can receive flush water volume V1 without overflowing. In other words, reference pressure Th3 is set to correspond to the water level that can receive flush water volume V1 without overflowing. In the flush process, if the detected pressure is below reference pressure Th5, a volume of flush water appropriate for the flush button selected by the user is supplied. This allows bowl 6b to be properly flushed.

[0054] (Correspondence) The reference pressure Th5 is an example of a "fourth threshold value."

[0055] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above examples are listed below.

[0056] (Variation 1) When the flush water restriction flag is set to on in S32 of the water level detection process, the user may be able to switch the flush water restriction flag from on to off. In this case, the water level detection process does not need to execute the processes from S34 onwards. In the water level detection process, the flush water restriction flag may be kept on until the user switches the flush water restriction flag from on to off.

[0057] (Variation 2) In the water level detection process, at least one of the processes of S20 and S22 may not be executed. If the process of S20 is not executed, the processes of S16 and S18 may not be executed. If the answer is NO in S22, the process of S222 may be executed.

[0058] (Variation 3) The control device 40 may be able to selectively supply one, two, or four or more different amounts of flush water. The control device 40 may adjust the amount of flush water by adjusting at least one of the opening period and opening degree of at least one of the flapper valve in the tank 2 and the water supply solenoid valve 3.

[0059] (Variation 4) In the water level detection process of the embodiment, the control device 40 compares the detected pressure with a reference pressure. In a variation, the control device 40 may convert the detected pressure to a water level and compare the converted water level with a threshold value of the reference water level. In this case, the control device 40 may previously store at least one of an arithmetic expression and a table for converting the detected pressure to a water level, and the water level threshold value.

[0060] (Variation 5) The water level detection device 10 does not have to detect the water level using pressure. The water level detection device 10 may detect the water level using a float placed inside the toilet device 6. The water level detection device 10 may detect the water level using the capacitance of an electrode pair placed inside the toilet device 6. The water level detection device 10 may detect the water level using an ultrasonic transmitter / receiver placed inside the toilet device 6.

[0061] (Variation 6) The control device 40 may be able to switch the cleaning restriction flag from on to off by at least one of the administrator and the user. In the water level detection process, after the process of S14, the control device 40 may keep the cleaning restriction flag on until at least one of the administrator and the user switches the cleaning restriction flag from on to off. The control device 40 may not execute the processes from S16 onwards.

[0062] (Variation 7) The control device 40 does not need to store the reference pressure Th2. In the water level monitoring process, in S12, the control device 40 may monitor the detected pressure until the detected pressure reaches or falls below the reference pressure Th1. If the detected pressure reaches or falls below the reference pressure Th1 (YES in S12), the control device 40 may proceed to processing in S14. In this variation, the reference pressure Th1 is an example of the "first threshold value" and the "second threshold value."

[0063] (Variation 8) The control device 40 may not store the reference pressure Th4. In the cleaning process, in S40, the control device 40 may detect that the detected pressure exceeds the reference pressure Th1. If the control device 40 detects that the detected pressure exceeds the reference pressure Th1, it may determine that a blockage has occurred (YES in S40). If the control device 40 does not detect that the detected pressure exceeds the reference pressure Th1, it may not determine that a blockage has occurred (NO in S40). In this variation, the reference pressure Th1 is an example of the "first threshold value" and the "third threshold value".

[0064] (Variant 9) Since each of the reference pressures Th1, Th2, Th4, Th5 and the change threshold value Th3 is a value for determining water level abnormality, the control device 40 may store values ​​obtained by learning control that corrects variations in the shape and construction state of the flush toilet.

[0065] The technical elements described in this specification or drawings may exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technologies illustrated in this specification or drawings may achieve multiple objectives simultaneously, and achieving one of those objectives alone is technically useful. [Explanation of symbols]

[0066] 2: Tank, 3: Water supply solenoid valve, 3s: Water supply pipe, 4: Flush pipe, 5: Clean water pipe, 6: Toilet device, 6b: Bowl, 6m: Toilet body, 8: Drain pipe, 10: Water level detection device, 11: Pressure sensor, 12: Purge pipe, 13: First detection pipe, 14: Second detection pipe, 14a: Second section, 14b: First section, 14c: Tip section, 15: Air tank, 16: Joint, 17: Three-way valve, 18: End face, 20: Rim water passage, 21: Rear water passage, 22: Left water passage, 24: Right water passage, 28: Bottom, 30: Storage space, 32: Through hole, 40: Control device, 50: Pump, 52: Air solenoid valve, 54: Air pipe, 60: Management terminal, 80: Operating device, 100: Flush toilet

Claims

1. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; The second threshold is a threshold for determining whether the water level in the bowl is high due to a drainage abnormality.

2. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; In the particular case, when a particular period has passed since the water level in the bowl became equal to or lower than the second threshold, the supply unit reduces the amount of flush water supplied to the bowl to the second amount.

3. 3. The flush toilet according to claim 2, wherein the supply unit increases the amount of flush water supplied to the bowl to the first amount when, in the specific case, the specific period has elapsed since the water level in the bowl became equal to or lower than the second threshold value.

4. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; a flush toilet in which, in the specific case, when the supply of the second amount of flush water to the bowl causes the water level in the bowl to reach a third threshold value that is greater than or equal to the first threshold value, the supply unit reduces the amount of flush water supplied to the bowl to be less than the second amount.

5. A flush toilet, a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; The flush toilet is a tank for storing the cleaning water to be supplied to the bowl; a water passage extending from a water supply pipe disposed outside the flush toilet to the bowl; The supply unit includes: When supplying the flush water to the bowl, the flush water stored in the tank and the flush water supplied from the clean water pipe through the water passage are supplied to the bowl, thereby supplying the first amount of flush water; In the specific case, the amount of flush water supplied to the bowl is reduced by at least one of stopping the flush water supplied from the tap water pipe through the water passage and reducing the amount of flush water supplied from the tank.

6. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; The supply unit increases the amount of flush water supplied to the bowl to the first amount when, after the specific case, the water level in the bowl is equal to or lower than a fourth threshold value that is lower than the second threshold value.

7. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; The supply unit increases the amount of flush water supplied to the bowl to the first amount if, after the specific case, the amount of decrease in the water level in the bowl per unit time is equal to or greater than a fifth threshold.

8. a toilet body having a bowl; a supply unit that supplies a first amount of cleaning water to the bowl, the supply unit reduces the amount of flush water supplied to the bowl to a second amount less than the first amount in a specific case where the water level in the bowl reaches or is equal to or less than a second threshold that is equal to or less than the first threshold after being equal to or greater than a first threshold; The supply unit is capable of supplying a plurality of amounts of flush water, including large flushes and small flushes, the first water amount is the amount of flush water during a large flush, The second water volume is the volume of flush water during a small flush.

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