Water level detection device

Abstract

To provide a technology for suppressing a situation in which washing water overflows from a toilet bowl device in the present specification.SOLUTION: A water level detection device disclosed by the present specification comprises: a water level detection part that detects a water level in a bowl of a toilet bowl device; and a control part that controls the water level detection part, wherein the control part obtains supply timing at which washing water is supplied to the toilet bowl device, and may cause the water level detection part to execute a first water level detection process for detecting the water level before the washing water is supplied to the toilet bowl device when the supply timing is obtained.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The technology disclosed in this specification relates to a water level detection device.

Background Art

[0002] Patent Document 1 discloses a toilet device that determines clogging of a toilet based on the water level in the toilet bowl. When there is clogging in the toilet, the supply of washing water to the toilet is prohibited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above toilet device, the detection result is obtained at a predetermined timing after the supply of washing water to the toilet is completed, and based on the detection result, clogging of the toilet is determined. If clogging occurs in the toilet and washing water is supplied at a timing other than the predetermined timing, the washing water may overflow from the toilet. This specification provides a technology for suppressing a situation where washing water overflows from the toilet device.

Means for Solving the Problems

[0005] The water level detection device disclosed by this specification includes a water level detection unit that detects the water level in the bowl of the toilet device, and a control unit that controls the water level detection unit. The control unit obtains a supply timing at which washing water is supplied to the toilet device, and when the supply timing is obtained, before the washing water is supplied to the toilet device, the water level detection unit may be made to execute a first water level detection process for detecting the water level.

[0006] Details and further improvements of the technology disclosed in this specification will be described in the following "Mode for Carrying Out the Invention". [Brief explanation of the drawing]

[0007] [Figure 1] A side view of a flush toilet according to the first embodiment is shown. [Figure 2] A rear perspective view of a flush toilet according to the first embodiment is shown. [Figure 3] This shows a cross-sectional view of the toilet device of the first embodiment at the center in the left-right direction. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Figure 5] A block diagram illustrating the general configuration of the water level detection device is shown. [Figure 6] This shows a graph of the pressure detected by the pressure sensor of the first embodiment. [Figure 7] A flowchart of the process performed by the control device of the first embodiment is shown. [Figure 8] A perspective view of the water level detection device according to the second embodiment is shown. [Figure 9] This shows a cross-sectional view of the toilet device, including the water level detection device of the third embodiment, at the center in the left-right direction. [Figure 10] A flowchart of the process performed by the control device of the third embodiment is shown. [Figure 11] This shows a cross-sectional view of the toilet device, including the water level detection device of the fourth embodiment, at the center in the left-right direction. [Figure 12] This shows a cross-sectional view of the toilet device, including the water level detection device of the fifth embodiment, at the center in the left-right direction. [Modes for carrying out the invention]

[0008] (First Embodiment) (Outline of the configuration of a flush toilet 100) As shown in Figure 1, the flush toilet 100 is a so-called wall-mounted toilet fixed to the wall 9. The flush toilet 100 comprises a toilet unit 6, a tank 2, and a water level detection device 10. The toilet unit 6 comprises a toilet body 6m and a flushing pipe 4. The toilet body 6m is made of ceramic. The toilet body 6m has a bowl 6b that receives waste. The tank 2 stores flushing water to wash the bowl 6b. The toilet unit 6 has a flush button (not shown) electrically connected to the tank 2. As shown in Figure 13, when the flush button is operated by the user, a motor drive device 508 built inside the tank 2 opens a flapper valve (not shown) located at the bottom of the tank 2, and flushing water in the tank 2 is supplied to the bowl 6b via the flushing pipe 4. As a result, the flushing water washes away the waste in the bowl 6b. In the toilet unit 6, flushing water from the tank 2 may be supplied to the bowl 6b not only by operating the flush button, but also by operating a lever located on the toilet unit 6. The flush button may be located on a remote controller electrically connected to the tank 2 via either a wired or wireless connection. Flushing water from the tank 2 may also be supplied to the bowl 6b without any user operation. For example, if the sensor does not detect a user, flushing water from the tank 2 may be supplied to the bowl 6b.

[0009] Hereinafter, the direction in which the tank 2 and the toilet bowl 6 are aligned will be referred to as the front-to-back direction. In the front-to-back direction, the side of the toilet bowl 6 that is positioned relative to the tank 2 will be referred to as the front side of the front-to-back direction, and the side of the tank 2 that is positioned relative to the wall 9 will be referred to as the rear side of the front-to-back direction. The horizontal direction perpendicular to the front-to-back direction will be referred to as the left-to-right direction. In the left-to-right direction, the far side of the page in Figure 1 will be referred to as the right side, and the near side of the page in Figure 1 will be referred to as the left side. In other words, the left and right directions correspond to the left and right as seen from the perspective of a user facing the flush toilet 100. The vertical direction perpendicular to the front-to-back direction will be referred to as the up-and-down direction. In the up-and-down direction, the side of the tank 2 that is positioned relative to the flush pipe 4 will be referred to as the upper side, and the side of the tank 2 that is positioned relative to the flush pipe 4 will be referred to as the lower side.

[0010] The toilet device 6 further comprises a toilet seat 6s, a toilet lid 6c, a functional unit 6f, and a drain pipe 8. The toilet seat 6s and toilet lid 6c are each connected to the toilet body 6m in a manner that allows them to be opened and closed. The functional unit 6f automatically opens the toilet lid 6c when a user approaches the flush toilet 100. The functional unit 6f may have functions such as local washing, warm air drying, and deodorizing. The drain pipe 8 connects the bowl 6b to the sewer pipe (not shown). The flushing water in the bowl 6b is discharged into the sewer pipe via the drain pipe 8. In Figure 2, the toilet seat 6s and toilet lid 6c are not shown.

[0011] The tank 2, flush pipe 4, and water level detection device 10 are isolated from the space where the flush toilet 100 is located by a wall 9. The user cannot see the part of the water level detection device 10 that is located on the outside (i.e., the back side) of the toilet unit 6. This improves the aesthetic appearance of the flush toilet 100. It also prevents the user from accidentally damaging or soiling the tank 2, flush pipe 4, and water level detection device 10 during cleaning or other maintenance. The wall 9 is provided with an openable and closable inspection opening (not shown), and workers can perform maintenance on the tank 2, flush pipe 4, and water level detection device 10 through the inspection opening in the wall 9.

[0012] The flushing pipe 4 extends downward from the bottom of the tank 2, bends and extends forward to connect with the toilet bowl body 6m. The flushing water stored in the tank 2 is supplied to the toilet bowl body 6m via the flushing pipe 4. A water supply pipe 3s is connected to the upper rear 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 to the tank 2. As shown in Figure 2, the water supply solenoid valve 3 is connected to the water supply pipe 5 via a shut-off valve 3f with a filter. Water is supplied to the water supply pipe 5 from a water source (not shown). The water supply solenoid valve 3 can prevent foreign matter from entering by taking in water through the shut-off valve 3f with a filter. The water supply solenoid valve 3 is always open except when there is a malfunction in the toilet bowl device 6. A ballcock (not shown) is located inside the tank 2. The ballcock is equipped with a float ball (not shown) that displaces vertically according to the water level of the flushing water in tank 2. When the water level of the flushing water in tank 2 rises to a predetermined level, the float ball rises, closing the ballcock. This stops the supply of tap water to tank 2. When the flushing water in tank 2 is supplied to the toilet device 6 and the water level in tank 2 drops, the float ball descends, opening the ballcock. As a result, tap water is supplied to tank 2 from the water supply pipe 3s.

[0013] (Internal structure of toilet unit 6) The internal structure of the toilet unit 6 will be explained with reference to Figures 3 and 4. Figure 3 shows a cross-sectional view of the toilet unit 6 cut in the center in the left-right direction. In Figure 3, the toilet seat 6s, toilet lid 6c, and drain pipe 8 are not shown. 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. The flushing 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 behind the bowl 6b at the upper end 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. The washing water in the tank 2 flows into the rim water passage 20 from the washing pipe 4. In the rim water passage 20, the washing water flows forward from the rear water passage 21, is diverted into each water passage 22, 24, and is sent into the bowl 6b. The washing water swirls and flows along the inner surface of the bowl 6b. As a result, the inner surface of the bowl 6b is washed.

[0015] As shown in FIG. 3, a through hole 32 is provided in the upper wall disposed above the rear water passage 21. The through hole 32 communicates the rim water passage 20 and the storage space 30 above the rear water passage 21. An air vent (not shown) is disposed at a portion defining the upper end of the storage space 30 of the toilet body 6m. When a drainage abnormality occurs and the washing water in the bowl 6b is not normally discharged, the water level of the washing water in the rim water passage 20 rises. When the water level of the washing water exceeds the through hole 32, the washing water pushes the air in the storage space 30 through the through hole 32. The air in the storage space 30 is discharged outside the storage space 30 when the air vent valve opens. As a result, the washing water flows into the storage space 30. The washing water in the storage space 30 is temporarily stored. When a drainage abnormality occurs in the bowl 6b, it is possible to prevent the washing water from overflowing from the bowl 6b by temporarily storing the washing water in the storage space 30. In a situation where the washing water in the bowl 6b is normally discharged, even when the water level of the washing water reaches the through hole 32, since the storage space 30 is a sealed space and there is air, the washing water does not flow into the storage space 30. Even if a little washing water flows into the storage space 30, the washing water flows out of the storage space 30 through the through hole 32 in accordance with the decrease in the water level of the washing water. Therefore, the washing water is not stored in the storage space 30.

[0016] (Configuration of the water level detection device 10) Referring to FIGS. 2 and 5, the configuration of the water level detection device 10 will be described. As shown in FIG. 2, the water level detection device 10 includes a control device 40, 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 control device 40, the pump 50, the air solenoid valve 52, and the pressure sensor 11 are housed in a box installed on the back of the tank 2. The actual box is covered with a cover from the rear side. In FIGS. 2 and 5, the illustration of the cover is omitted.

[0017] The control device 40 controls the flushing toilet 100. The control device 40 includes a CPU (abbreviation of Central Processing Unit), a RAM (abbreviation of Random Access Memory), a ROM (abbreviation of Read Only Memory), etc., which are hardware processors. When the control device 40 receives an operation of the flushing button, it opens a flapper valve 504 (not shown) disposed on the bottom surface of the tank 2. Thereby, the flushing water in the tank 2 is supplied to the toilet body 6m through the flushing pipe 4.

[0018] The first detection pipe 13 and the second detection pipe 14 each have a hollow tubular shape. The first detection pipe 13 is made of resin. The second detection pipe 14 is made of copper. 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 flushing pipe 4 and extends to the rear of the toilet device 6. The end of the second detection pipe 14 on the side opposite to the rim water passage 20 is connected to the first detection pipe 13 via a three-way joint 17. By making the second detection pipe 14 disposed in the rim water passage 20 of copper, it is possible to suppress the growth of mold and bacteria in the second detection pipe 14. The second detection pipe 14 may be made of a material such as silver, in addition to copper, which is difficult for mold and bacteria to grow.

[0019] The first detection pipe 13 connects the three-way joint 17 and the pressure sensor 11. An air tank 15 is positioned in the first detection pipe 13 between the pressure sensor 11 and the three-way joint 17. The cross-section of the air tank 15 perpendicular to the longitudinal direction of the first detection pipe 13 is larger than the cross-section of the first detection pipe 13 perpendicular to the longitudinal direction. Since the pressure sensor 11 is a high-precision micro-pressure sensor, it is highly sensitive to even slight pressure fluctuations caused by turbulence in the cleaning water flow. The air tank 15 can smooth out the turbulence in the pressure waveform caused by turbulence in the cleaning water flow. In a pressure sensor 11 capable of detecting minute pressure fluctuations, the air tank 15 suppresses the turbulence in the detected pressure, thereby preventing false detections by the pressure sensor 11. Furthermore, by positioning the air tank 15 upstream of the three-way joint 17, it is possible to suppress the inflow of cleaning water into the air tank 15.

[0020] A purge pipe 12 is connected to the three-way joint 17. The purge pipe 12 is connected to the pump 50 via an air solenoid valve 52.

[0021] 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 is equipped with a strain gauge resistor (not shown) inside. The displacement of the strain gauge resistor changes according to 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. 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, a semiconductor diaphragm type, or even at least one of a quartz pressure sensor and a capacitive bridge type sensor.

[0022] The first detection tube 13 is connected to the bowl 6b via the second detection tube 14. When the water level in the bowl 6b rises, the tip of the second detection tube 14 is blocked, and the pressure inside the second detection tube 14 increases. As the pressure inside the second detection tube 14 increases, the pressure inside the first detection tube 13 also increases. Therefore, the value detected by the pressure sensor 11 fluctuates according to the water level in the bowl 6b.

[0023] As shown by the dashed line in Figure 5, the control device 40 is communicatively connected to the water supply solenoid valve 3, pressure sensor 11, pump 50, and air solenoid valve 52. The control device 40 controls the water supply solenoid valve 3, pressure sensor 11, pump 50, and air solenoid valve 52. The control device 40 is communicatively connected to the management terminal 60. The management terminal 60 is a terminal operated by the administrator of the flush toilet 100, and is located, for example, at the management company of the building where the flush toilet 100 is installed. The control device 40 transmits the usage status of the flush toilet 100, the drainage status, etc. to the management terminal 60. The administrator 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 a portable terminal, PC, etc., owned by at least one of the users of the flush toilet 100 and the cleaning company.

[0024] (Detailed structure of the second detection tube 14) As shown in Figure 3, the second detection pipe 14 penetrates the outer wall of the flush pipe 4 via a joint 16 and extends forward. The second detection pipe 14 comprises an internal portion 14b located inside the toilet device 6 and an external portion 14a located outside the toilet device 6. The internal portion 14b of the second detection pipe 14 passes inside the flush pipe 4 and is located in the rim water passage 20 of the toilet body 6m.

[0025] By passing the second detection pipe 14 through the flushing pipe 4 connected to the back of the toilet bowl body 6m, each component of the water level detection device 10 (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, fitting 16, and three-way fitting 17), including the external component 14a of the device, can be positioned in a location inaccessible to the user. As a result, it is possible to prevent the components of the water level detection device 10 from coming into contact with the user. In particular, it is possible to suppress at least one of displacement and damage to the second detection pipe 14. Each component of the water level detection device 10 can be made less visible to the user. As a result, the aesthetic design of the flush toilet 100 can be improved.

[0026] As shown in Figure 4, the internal portion 14b of the device bends to the left (i.e., downwards in the plane of Figure 4) in the rear water passage 21 and extends into the left water passage 22. The tip portion 14c of the internal portion 14b is located within the left water passage 22. An opening is provided at the end face 18 of the tip portion 14c, which connects the internal portion 14b to the left water passage 22. The second detection pipe 14 connects the left water passage 22 and the pressure sensor 11 via the first detection pipe 13. When a drainage abnormality occurs and the water level of the cleaning water rises to the left water passage 22, the opening at the end face 18 of the second detection pipe 14 is blocked by the cleaning water. As a result, the pressure inside the second detection pipe 14 increases. The pressure inside the second detection pipe 14 is detected by the pressure sensor 11 via the first detection pipe 13.

[0027] The higher the water level of the cleaning water in bowl 6b, the greater the amount of cleaning water located above the end face 18. The higher the water level of the cleaning water in bowl 6b, the higher the pressure in the second detection tube 14 and the first detection tube 13. In other words, the water level of the cleaning water in bowl 6b is correlated with the pressure in the second detection tube 14 and the first detection tube 13. Therefore, the water level detection device 10 can detect the water level in bowl 6b by utilizing the pressure in the second detection tube 14 and the first detection tube 13.

[0028] The water level detection device 10 places a second detection pipe 14 in the left-side water passage 22 that supplies flushing water to the bowl 6b, and uses the pressure inside the second detection pipe 14 to determine the water level of the flushing water in the bowl 6b. Therefore, it is not necessary to secure a separate space within the toilet unit 6 for placing the second detection pipe 14. As a result, the water level of the bowl 6b can be detected without significantly changing the structure of the toilet unit 6, for example, by placing the second detection pipe 14 in the left-side water passage 22 of an existing toilet unit 6. The water level detection device 10 can be installed in a general-purpose toilet unit 6.

[0029] Since foreign matter such as dirt is present in the bowl 6b and trap section along with the washing water, the detected water level is affected by the foreign matter. As a result, the detected water level becomes unstable. In this embodiment, by placing the tip portion 14c of the second detection pipe 14 in the rim water passage 20, the influence of foreign matter on the detected water level can be suppressed.

[0030] In the rim water channel 20, turbulence occurs in the rear water channel 21 before the branching point, which receives the cleaning water flowing in from the cleaning pipe 4. The turbulence of the cleaning water is suppressed as it flows from the rear water channel 21 toward the left and right water channels 22 and 24. By positioning the tip portion 14c of the second detection pipe 14 in the left water channel 22 after the branching point, the pressure on the second detection pipe 14 due to the flow of cleaning water can be suppressed. This allows for proper detection of the water level of the cleaning water in the bowl 6b.

[0031] Since the internal part 14b of the device is located within the rim water passage 20, it is covered by the outer wall of the toilet bowl body 6m that defines the rim water passage 20. Therefore, it is possible to suppress the adhesion of dirt to the internal part 14b of the device. For example, when cleaning the bowl 6b, it is possible to suppress at least one of displacement or damage to the tip portion 14c caused by contact with a cleaning tool.

[0032] (Purge process) When cleaning water is supplied to bowl 6b, the cleaning water passes through the left-side water channel 22 while being mixed with air in the cleaning channel. The inner circumferential surface of the tip portion 14c is affected by the large pressure changes that occur when cleaning water is supplied to bowl 6b, and cleaning water may enter, creating multiple layers of water and air. As shown in Figure 5, cleaning water that enters the second detection tube 14 may form a water film 72 that blocks the second detection tube 14. When the second detection tube 14 is blocked by the water film 72, pressure may not be transmitted even though the water level in bowl 6b has reached the second detection tube 14. In this case, the control device 40 cannot accurately detect the water level of the cleaning water in bowl 6b using the pressure value detected by the pressure sensor 11.

[0033] A purge pipe 12 is connected to the second detection pipe 14 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. During the purging process, the control device 40 opens the air solenoid valve 52 at the same time as operating the pump 50. As a result, air 70 is pumped into the second detection pipe 14 via the purge pipe 12 and the three-way joint 17. The air 70 pushes the water film 72 and the air layer inside the second detection pipe 14 out into the left-side waterway 22. After a predetermined time has elapsed, the control device 40 stops the operation of the pump 50 and simultaneously closes the air solenoid valve 52. This suppresses the formation of a 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 do not affect the detection pressure. Note that the air solenoid valve 52 may be replaced with a check valve.

[0034] (Pressure changes during washing) Referring to Figure 6, the pressure changes in the first detection tube 13 and the second detection tube 14 during the flushing period Tc will be explained. The flushing period Tc is the period from when the flush button operation is accepted at timing T1 until the supply of flushing water ends. The flushing period Tc includes the time required after the supply of flushing water ends for the flushing water to be drained and for the detected pressure by the pressure sensor 11 to stabilize sufficiently. The flushing period Tc is, for example, about 20 seconds and is preset by the manufacturer of the flush toilet 100, etc., according to the capacity of the tank 2, bowl 6b, etc.

[0035] (Pressure changes under normal conditions) First, the pressure inside the first detection pipe 13 and the second detection pipe 14 (hereinafter sometimes referred to as the detected pressure) when the toilet bowl body 6m can normally discharge flushing water (hereinafter sometimes referred to as the normal state) will be explained using the solid waveform W1.

[0036] During the period before the flush button is pressed at timing T1, the flush water does not pass through the left-side water channel 22. Therefore, the detected pressure is maintained at a value approximating atmospheric pressure Ap.

[0037] When the control device 40 receives an operation of the cleaning button at timing T1, it activates the pump 50 at timing T2, and stops the pump 50 after a predetermined time has elapsed. The activated pump 50 pumps air into the second detection tube 14. As a result, the detected pressure rises instantaneously, as shown by the pressure peak P1.

[0038] Subsequently, at timing T5, the flapper valve (not shown) of tank 2 is opened, and the supply of washing water to bowl 6b begins. This causes the water level of the washing water in tank 2 to drop. As a result, the float ball of the ball tap descends, the ball tap opens, and fresh tap water is supplied to tank 2 from the water supply pipe 3s (see Figure 1). Consequently, the fresh tap water supplied to tank 2 is also supplied to bowl 6b as washing water. This allows the large amount of washing water to wash away the dirt in bowl 6b.

[0039] When the supply of cleaning water to bowl 6b begins, the cleaning water flows into the left-side water channel 22. At this time, the cleaning water blocks the opening at the end face 18 of the second detection tube 14. As a result, the detection pressure increases. While the cleaning water is being supplied, the volume and pressure of the cleaning water are high immediately after the supply begins, and then the volume and pressure of the cleaning water gradually decrease.

[0040] After the supply of cleaning water is started at timing T5, the control device 40 operates the pump 50 again at timing T7. The pump 50 pumps air into the second detection tube 14. After a predetermined time has elapsed since the pump 50 started operating, the pump 50 is stopped. As a result of this operation, the detected pressure rises instantaneously again, as shown by the pressure peak P2.

[0041] Subsequently, the cleaning water continues to flow into bowl 6b until timing T9. As a result, the detected pressure repeatedly rises and falls until timing T9. When a predetermined amount of cleaning water from tank 2 flows into bowl 6b, the float connected to the flapper valve 504 descends along with the water level of the cleaning water in tank 2. This closes the flapper valve 504 at timing T9. This stops the supply of cleaning water from tank 2 to bowl 6b. As a result, the detected pressure gradually decreases while repeatedly rising and falling.

[0042] After the flapper valve is closed, the cleaning water remaining in the cleaning pipe 4 and rim water channel 20 is sent into the bowl 6b. The detected pressure gradually stabilizes and is held at atmospheric pressure Ap, and cleaning is completed at timing T10. At timing T10, the control device 40 operates the pump 50 again and stops the pump 50 after a predetermined time has elapsed. As a result, the detected pressure rises instantaneously, as shown by the pressure peak P3. In this way, during the cleaning period Tc, the normal detected pressure changes at each timing, as shown by the waveform W1, and is finally held at atmospheric pressure Ap.

[0043] (Pressure changes when a drainage malfunction occurs) The changes in detected pressure when a drainage abnormality occurs in the toilet device 6 due to a blockage will be explained using the thin dashed waveform W2 and the thick dashed waveform W3. In the following, the drainage abnormality that occurs in the toilet device 6 will be explained in two stages: the first drainage abnormality shown by waveform W2 and the second drainage abnormality shown by waveform W3.

[0044] The situation differs between the first and second drainage anomalies. In the first drainage anomaly, the water level in bowl 6b is at a normal level, but foreign matter is clogging the drainage path within bowl 6b and the drainage path downstream of bowl 6b, causing the drainage path to narrow compared to normal, resulting in a rise in the water level. The drainage path downstream of bowl 6b includes the drain pipe 8 and, for example, the drain pipe within the building where the flush toilet 100 is located (not shown). In the second drainage anomaly, the water level in bowl 6b has already risen above the normal level, and even if a smaller amount of flushing water is supplied to bowl 6b than in the first drainage anomaly, the detected pressure will rise. In the second drainage anomaly, similar to the first drainage anomaly, foreign matter is clogging the drainage path within bowl 6b and the drainage path downstream of bowl 6b, causing the drainage path to narrow compared to normal, resulting in a rise in the water level.

[0045] (Pressure changes during the first drainage abnormality) As can be seen by comparing waveforms W1 and W2, the detection pressure during the first drainage abnormality is approximately the same as the detection pressure during normal operation between timings T1 and T7. During the first drainage abnormality, the amount of cleaning water passing through the left-side water channel 22 when supplying cleaning water is the same as during normal operation. However, during the first drainage abnormality, the amount of water drained per unit time is lower than during normal operation, so the water level in bowl 6b does not drop as much as during normal operation. As shown in waveform W2, the detection pressure during the first drainage abnormality is higher than the detection pressure during normal operation from timing T7 onward. Even when the flapper valve 504 is closed at timing T9, the opening of the tip portion 14c of the second detection pipe 14 is blocked by the water in bowl 6b, so the detection pressure during the first drainage abnormality does not drop to atmospheric pressure Ap. The amount of cleaning water supplied to bowl 6b during one cleaning cycle is less than the capacity of bowl 6b. Therefore, during the first drainage abnormality, the supply of cleaning water ends before the cleaning water overflows from bowl 6b. From timing T10 onward, the detection pressure during the first drainage abnormality is maintained at a pressure slightly lower than the detection pressure that rose when the wash water was supplied at timing T5.

[0046] (Pressure changes during the second drainage abnormality) During the second drainage anomaly, the water level in bowl 6b has risen to the vicinity of the rim waterway 20 (for example, during the first drainage anomaly), and cleaning water is supplied to bowl 6b. During the second drainage anomaly, the detected pressure may already be higher than atmospheric pressure Ap before the cleaning water is newly supplied. If the water level in bowl 6b does not exceed the rim waterway 20 during the timing T1 to T5 until the cleaning water is supplied, waveform W3 will be the same as waveforms W1 and W2. If the water level in bowl 6b exceeds the opening of the end face 18 during the timing T1 to T5 until the cleaning water is supplied, waveform W3 will be higher than atmospheric pressure Ap. During the second drainage anomaly, once cleaning water is supplied to bowl 6b, the water level in bowl 6b will continue to rise. Therefore, as shown in waveform W3, the detected pressure during the second drainage anomaly will be higher than the detected pressure during the first drainage anomaly. In the case of a second drainage abnormality, the bowl 6b may overflow because it cannot accept the amount of cleaning water supplied to it during a single flush. The detected pressure during a second drainage abnormality is maintained at a higher value than the detected pressure during a first drainage abnormality.

[0047] The control device 40 detects the water level of the flushing water in the bowl 6b by comparing the detected pressure received from the pressure sensor 11 with a reference pressure. The control device 40 uses the detected pressure received from the pressure sensor 11 to determine the water level of the flushing water in the bowl 6b. As described above, the detected pressure changes according to the water level of the flushing water in the bowl 6b. The control device 40 stores the reference pressures Th1, Th2, Th3, and Th4 in advance. Depending on the timing of pressure detection, the control device 40 uses each of the reference pressures Th1 to Th4 to perform an abnormality detection process to detect the occurrence of a drainage abnormality in the toilet device 6. In Figure 6, the reference pressures Th1 to Th4 that the control device 40 uses as a comparison target for the detected pressure at each timing are shown by dashed lines. Note that since each of the reference pressures Th1 to Th4 is a value used to distinguish between normal and abnormal conditions, it may be possible to store values ​​obtained by learning control that corrects for variations in toilet shape and construction conditions.

[0048] (Normal abnormality detection process performed by the control device 40) When the flush toilet 100 is installed, the water level detection device 10 is activated. When the water level detection device 10 is activated, the control device 40 performs abnormality detection processing. The abnormality detection processing includes normal abnormality detection processing and flushing abnormality detection processing. In normal abnormality detection processing, the control device 40 detects that the pressure in the second detection pipe 14 exceeds the reference pressure Th2 immediately after receiving the user's operation of the flush button and before flushing begins. In normal abnormality detection processing, the control device 40 detects that the pressure in the second detection pipe 14 exceeds the reference pressure Th2 for a predetermined period after the supply of flushing water. When the flushing water is drained normally, the water level in the bowl 6b does not reach the second detection pipe 14, and the opening of the end face 18 is not blocked. The detected pressure is approximated by atmospheric pressure Ap. In a situation where a drainage abnormality occurs, if water is supplied to bowl 6b from a source other than tank 2, such as by directly supplying washing water to bowl 6b using a bucket, the water level in bowl 6b may reach the second detection pipe 14. In this case, the detection pressure will rise. The reference pressure Th2 is set to a value that allows detection of a state where the opening of the second detection pipe 14 is blocked by water in bowl 6b by comparing it with the detection pressure. This makes it possible to detect a drainage abnormality when water is supplied to bowl 6b from a source other than tank 2.

[0049] (Anomaly detection process during cleaning performed by the control device 40) In the cleaning abnormality detection process, the control device 40 performs abnormality detection processing during the cleaning period Tc, using the reference pressures Th1 to Th4. When the control device 40 receives an operation of the cleaning button (timing T1 in Figure 6), it receives a signal indicating that the operation of the cleaning button has been received, and starts the process shown in Figure 7.

[0050] In S2, the control device 40 operates the pump 50 (timing T2 in Figure 9), and after a predetermined time has elapsed, stops operating the pump 50. In S3, the control device 40 determines whether the timing of receiving the reception signal is such that a predetermined period has elapsed since the last time flushing water was supplied to the bowl 6b. The predetermined period is predetermined and stored in the memory of the control device 40. The predetermined period is the period after supplying flushing water to the bowl 6b during which the water level in the bowl 6b is higher than when no flushing water is supplied, i.e., the period during which flushing water remains without being drained. The predetermined period is, for example, the flushing period Tc. The predetermined period may also be a period appropriately determined by the structure of the toilet device 6. If it is determined that the timing of receiving the reception signal is such that a predetermined period has elapsed since the last time flushing water was supplied to the bowl 6b (YES in S3), the process proceeds to S4. If the timing of receiving the reception signal is such that a predetermined period has not elapsed since the last time flushing water was supplied to the bowl 6b (NO in S3), the process proceeds to S5.

[0051] In S4, the control device 40 detects that the detected pressure exceeds the reference pressure Th2 (between timing T3 and T4). In S5, the control device 40 detects that the detected pressure exceeds the reference pressure Th3 (between timing T3 and T4).

[0052] Through the processes from S2 to S5, the control device 40 pumps air 70 (see Figure 5) into the second detection tube 14 using the pump 50, and then detects the water level in the bowl 6b. The pressure sensor 11 can detect the detection pressure while suppressing the formation of a water film 72 on the inner surface of the second detection tube 14. As a result, the pressure detected by the pressure sensor 11 can be used to appropriately determine whether or not the opening at the tip portion 14c of the second detection tube 14 is blocked by the water in the bowl 6b.

[0053] As shown in Figure 6, the reference pressure Th2 is higher than atmospheric pressure Ap. The reference pressure Th2 is set to a value that allows detection of the blockage of the opening of the second detection tube 14 by the cleaning water in bowl 6b, by comparing it with the detection pressure. The reference pressure Th2 is lower than the reference pressure Th3. When the reference pressure Th2 is used, the cleaning button is pressed and cleaning water is about to be supplied from tank 2.

[0054] The reference pressure Th3 is higher than atmospheric pressure Ap. In the water level detection device 10, if a predetermined period has not elapsed since the last supply of flushing water to the bowl 6b, the water level may be high even though there is no serious blockage in the toilet device 6, as shown by waveform W3 in Figure 6, because flushing water remains in the bowl 6b. In S5, in a situation where a predetermined period has not elapsed since the last supply of flushing water to the bowl 6b, a reference pressure Th3 that is higher than the reference pressure Th2 used when a predetermined period has elapsed since the last supply of flushing water to the bowl 6b is used.

[0055] In S4, if the detected pressure exceeds the reference pressure Th2 (YES in S4), proceed to S54. Similarly, in S5, if the detected pressure exceeds the reference pressure Th3 (YES in S5), proceed to S54. In S54, the control device 40 does not supply cleaning water to the bowl 6b. In this case, even though the user has pressed the cleaning button, the flapper valve 504 is not opened. That is, the control device 40 does not start cleaning if the detected pressure exceeds the reference pressure Th2 in S4 or the reference pressure Th3 in S5. This prevents cleaning water from being supplied to the bowl 6b, where a drainage abnormality has occurred and the water level of the cleaning water has already risen. This prevents cleaning water from overflowing from the bowl 6b.

[0056] If, in S4, the detected pressure does not exceed the reference pressure Th2 (NO in S4), or if, in S5, the detected pressure does not exceed the reference pressure Th3 (NO in S5), the control device 40 proceeds to S10. In S10, the control device 40 opens the flapper valve 504 of the tank 2 and starts cleaning the bowl 6b (timing T5).

[0057] Next, in S20, the control device 40 detects that the detected pressure exceeds the reference pressure Th4 (between timings T4 and T6). If the detected pressure exceeds the reference pressure Th4 (YES in S20), the control device 40 proceeds to S52.

[0058] In S52, the control device 40 stops the water supply to tank 2. Specifically, the control device 40 closes the water supply solenoid valve 3 (see Figure 5). This stops the supply of tap water from the water supply pipe 5 to tank 2. During cleaning, in addition to the cleaning water originally stored in tank 2, tap water supplied from the water supply pipe 5 is also supplied to bowl 6b via tank 2 as cleaning water. If the detected pressure exceeds the reference pressure Th4 immediately after the supply of cleaning water (YES in S20), the water supply to tank 2 is stopped, thereby reducing the amount of cleaning water supplied to bowl 6b in the event of a drainage abnormality. As a result, overflow from the top of bowl 6b is prevented in the event of a drainage abnormality, and even if cleaning water overflows from the top of bowl 6b, the amount of overflowing cleaning water can be reduced. When the process in S52 is completed, the process proceeds to S54.

[0059] If the detected pressure is blocked and does not exceed the reference pressure Th4 (NO in S20), the control device 40 operates the pump 50 in S22 (timing T7 in Figure 6), and stops the operation of the pump 50 after a predetermined time has elapsed. While the pump 50 is operating, the pressure in the second detection pipe 14 rises regardless of the water level. While the pump 50 is operating, the control device 40 does not compare the detected pressure with the reference pressure. This prevents the system from mistakenly determining that the water level in the bowl 6b has risen.

[0060] At timings T5 to T7, immediately after the cleaning water passes through the left-side water channel 22, the opening of the tip portion 14c of the second detection pipe 14 is temporarily blocked by the cleaning water supplied from the tank 2 to the bowl 6b. Immediately after the start of cleaning water supply (timing T5), the pressure of the cleaning water flowing through the rim water channel 20 is high. In this case, the detection pressure temporarily rises regardless of whether or not a drainage abnormality has occurred. As shown in Figure 6, the detection pressure immediately after the start of cleaning water supply (timing T5) may be higher than the reference pressure Th3. If the detection pressure is compared with the reference pressure Th3 immediately after the start of cleaning water supply, the control device 40 may execute the process in S52 even though the water level of the cleaning water in the bowl 6b has not risen due to a drainage abnormality. As a result, the amount of cleaning water supplied is reduced. Immediately after the start of cleaning water supply (between timings T4 and T6), the control device 40 compares the detection pressure with a reference pressure Th4, which is higher than the reference pressure Th3. This allows the control device 40 to prevent a reduction in the amount of cleaning water supplied due to a temporary pressure increase that occurs immediately after the start of cleaning water supply. On the other hand, immediately after the start of cleaning water supply, the amount of water supplied to bowl 6b is the highest during the cleaning water supply. Therefore, if a drainage abnormality occurs, the water level in bowl 6b will rise significantly. Immediately after the start of cleaning water supply, the reference pressure Th4 can be used to detect a situation in which the water level in bowl 6b rises significantly due to a drainage abnormality.

[0061] In S30, the control device 40 detects that the detected pressure exceeds the reference pressure Th3 (between timings T8 and T10). If the detected pressure exceeds the reference pressure Th3 (YES in S30), the control device 40 proceeds to S52. As a result, the supply amount of cleaning water is reduced. Between timings T8 and T10, the supply of cleaning water from tank 2 continues. The opening of the tip portion 14c of the second detection pipe 14 is temporarily blocked by the cleaning water supplied from tank 2 to bowl 6b. By setting the reference pressure Th3 to a pressure higher than the reference pressure Th2, the control device 40 can detect the occurrence of a drainage abnormality even during the cleaning period Tc.

[0062] Between timings T8 and T10, time has passed since the start of the cleaning water supply, and the supply volume and pressure of the cleaning water have decreased compared to immediately after the start of the cleaning water supply. Therefore, between timings T8 and T10, the pressure in the second detection tube 14 does not rise compared to immediately after the start of the cleaning water supply (between timings T4 and T6). By setting the reference pressure Th3 used between timings T8 and T10 lower than the reference pressure Th4 used between timings T4 and T6, it is possible to detect earlier a condition in which the water level in the bowl 6b rises significantly due to a drainage abnormality while time has passed since the start of the cleaning water supply.

[0063] The control device 40 uses the detected pressure received from the pressure sensor 11 to detect the water level in the bowl 6b while cleaning water is being supplied to the bowl 6b. If a drainage abnormality occurs while cleaning water is being supplied, and the supply rate is not reduced, cleaning water may overflow from the top of the bowl 6b. By detecting the water level in the bowl 6b while cleaning water is being supplied, the control device 40 can detect the occurrence of a drainage abnormality while cleaning water is being supplied and prevent the cleaning water from overflowing.

[0064] If the detected pressure is blocked and does not exceed the reference pressure Th3 (NO in S30), the control device 40 detects in S32 that the drainage period has elapsed. The drainage period is the period from timing T9, when the flapper valve 504 is closed, to timing T10, and is the period from when the cleaning water supplied from the tank 2 is sent to the bowl 6b until the cleaning water no longer flows into the rim water channel 20. The drainage period is preset according to the capacity of the tank 2, the size of the bowl 6b, etc. If the drainage period has not elapsed (NO in S32), the control device 40 executes the process in S30 again. That is, the control device 40 repeatedly detects that the detected pressure exceeds the reference pressure Th3 until the drainage period has elapsed (between timings T8 and T10).

[0065] When the drainage period has elapsed (YES in S32), in S34, the control device 40 operates the pump 50 (timing T10), and after a predetermined time has elapsed, stops the operation of the pump 50. The control device 40 does not compare the detected pressure with the reference pressure while the pump 50 is operating. Next, in S40, the control device 40 detects that the detected pressure exceeds the reference pressure Th2 (between timings T11 and T12). If the detected pressure does not exceed the reference pressure Th2 (NO in S40), in S42, the control device 40 detects that a predetermined period Ta (see Figure 11) has elapsed. If the predetermined period Ta has not elapsed (NO in S42), the control device 40 executes the process in S40 again. That is, the control device 40 repeatedly detects that the detected pressure exceeds the reference pressure Th2 until the predetermined period Ta has elapsed (between timings T11 and T12). When the predetermined period Ta has elapsed (YES in S42), the control device 40 terminates the process in Figure 12. Alternatively, instead of setting a predetermined period Ta, the system may be designed to detect when the pressure exceeds the reference pressure Th2 until cleaning begins.

[0066] The control device 40 detects when the detected pressure exceeds the reference pressure Th3 while flushing water is being supplied (between timings T8 and T10), and during a predetermined period Ta (between timings T11 and T12), it detects when the detected pressure exceeds the reference pressure Th2, which is lower than the reference pressure Th3. During the predetermined period Ta, it uses the reference pressure Th2, which is lower than the reference pressure Th3, to detect the occurrence of a drainage abnormality. The control device 40 can accurately detect the occurrence of a drainage abnormality in the toilet device 6 even if the water level in the bowl 6b changes due to the supply of flushing water.

[0067] If the detected pressure exceeds the reference pressure Th2 (YES in S40), the control device 40 proceeds to S54. In S54, the control device 40 prohibits cleaning. Specifically, even if the control device 40 receives a press of the cleaning button, it does not open the flapper valve 504. Even if the cleaning button is pressed, the cleaning water in the tank 2 is not supplied to the bowl 6b.

[0068] If the detected pressure exceeds the reference pressure Th3 (YES in S30), the control device 40 reduces the amount of cleaning water supplied to the bowl 6b by stopping the water supply to the tank 2 in S52. Furthermore, if the detected pressure exceeds the reference pressure Th3 (YES in S30), even if the cleaning button is pressed for a predetermined period, the control device 40 will not supply cleaning water from the tank 2 to the bowl 6b. When the detected pressure exceeds the reference pressure Th3, the water level of the cleaning water in the bowl 6b is high, and there is a high possibility that the cleaning water will overflow from the top of the bowl 6b. When a second drainage abnormality occurs, in which there is an even higher possibility of overflow from the top of the bowl 6b, the control device 40 performs a process to change the amount of cleaning water supplied. This makes it possible to suppress the overflow of cleaning water from the top of the bowl 6b when a second drainage abnormality occurs. After the control device 40 stops the water supply to the tank 2 in S52, the flapper valve of the tank 2 is closed (i.e., the supply of cleaning water from the tank 2 to the bowl 6b is stopped), and after a predetermined time has elapsed, the water supply solenoid valve 3 is opened again. In a modified example, the control device 40 may perform a process to change the amount of cleaning water supplied by using at least one of the following: forcibly closing the flapper valve during cleaning; arranging a valve device to block the cleaning pipe 4 and blocking the cleaning pipe 4; and sending the cleaning water flowing through the cleaning pipe 4 to the drain pipe 8 without passing through the bowl 6b.

[0069] If the detected pressure exceeds the reference pressure Th2 (YES in S40), the supply of cleaning water from tank 2 to bowl 6b has already ended, and the process to reduce the amount of cleaning water supplied to bowl 6b is not performed. If the detected pressure exceeds the reference pressure Th2 (YES in S40), even if the cleaning button is pressed within a predetermined period, the cleaning water in tank 2 will not be supplied to bowl 6b.

[0070] Next, in S56, the control device 40 notifies the management terminal 60 (see Figure 10) of the occurrence of a drainage abnormality. Specifically, if the result of any of the processes in S4, S5, S30, and S40 is YES, the control device 40 transmits to the management terminal 60 information indicating that an abnormality has occurred in the water level of bowl 6b and information indicating that a blockage has occurred in bowl 6b. The management terminal 60 outputs the information received from the control device 40, which indicates that an abnormality has occurred in the water level of bowl 6b and information indicating that a blockage has occurred in bowl 6b. If the result of the process in S20 is YES, the control device 40 transmits to the management terminal 60 information indicating that the water in bowl 6b is overflowing. The management terminal 60 outputs the information received from the control device 40, which indicates that the water in bowl 6b is overflowing. The output includes the management terminal 60 displaying an image representing the information received from the control device 40 on the display unit and emitting sound representing the information received from the control device 40 from the sound output unit. This allows the administrator of the flush toilet 100 to become aware of the occurrence of a drainage problem.

[0071] In S60, the control device 40 detects that the detected pressure is below the reference pressure Th1. If the detected pressure is not below the reference pressure Th1 (NO in S60), the control device 40 repeats the process in S60 until the detected pressure falls below the reference pressure Th1. As shown in Figure 6, the reference pressure Th1 is slightly higher than atmospheric pressure Ap. The reference pressure Th1 is set to a value that allows detection of the state in which the opening of the second detection pipe 14 is exposed to the washing water by comparing it with the detected pressure. By comparing the detected pressure with the reference pressure Th1, the control device 40 can detect that the water level of the washing water in the bowl 6b is below the second detection pipe 14, i.e., that the drainage abnormality has been resolved.

[0072] For example, if a drainage abnormality caused by a toilet paper blockage resolves itself relatively quickly, or if the drainage abnormality is resolved by the administrator, at least one of these causes the water level of the flushing water in the bowl 6b to drop and the detected pressure to fall below the reference pressure Th1 (YES in S60), then in S62, the control device 40 releases the flushing prohibition in S54. By detecting the resolution of the drainage abnormality in the S60 process and releasing the flushing prohibition in the S62 process, the control device 40 can avoid continuing the flushing prohibition for a drainage abnormality that has already been resolved. Subsequently, in S64, the control device 40 notifies the management terminal 60 that the drainage abnormality has been resolved and terminates the flushing abnormality detection process. This allows the administrator of the flush toilet 100 to recognize that the drainage abnormality has been resolved.

[0073] In the water level detection device 10, the water level of the bowl 6b is detected by the pressure sensor 11. The pressure sensor 11 has higher accuracy in detecting the water level of the bowl 6b while cleaning water is being supplied compared to other sensors such as float sensors, capacitance sensors, and ultrasonic sensors. Therefore, the water level detection device 10 can detect the water level of the bowl 6b more accurately than configurations that detect the water level using other sensors.

[0074] In the cleaning abnormality detection process, the water level detection process differs depending on whether a predetermined period has elapsed since the last supply of cleaning water to bowl 6b when the reception signal is received. Specifically, if a predetermined period has elapsed since the last supply of cleaning water to bowl 6b when the reception signal is received, the reference pressure Th2 is used in S4. If a predetermined period has not elapsed since the last supply of cleaning water to bowl 6b when the reception signal is received, a reference pressure Th3, which is higher than the reference pressure Th2, is used in S5. With this configuration, the water level can be detected using a reference pressure that matches the water level of the cleaning water accumulated in bowl 6b. With this configuration, it is possible to prevent cleaning from being prohibited in S54 even if no serious blockage has occurred when a predetermined period has not elapsed since the last supply of cleaning water to bowl 6b.

[0075] (Correspondence) Pump 50, air solenoid valve 52, pressure sensor 11, first detection pipe 13, and second detection pipe 14 are examples of a "water level detection unit," and control device 40 is an example of a "control unit." The process in S4 is an example of a "first water level detection process," and the process in S5 is an example of a "second water level detection process." Reference pressure Th2 is an example of a "first reference water level," reference pressure Th3 is an example of a "second reference water level," and reference pressure Th4 is an example of a "third reference water level."

[0076] (Second Embodiment) As shown in Figure 8, the flush toilet 100 of this embodiment is equipped with a water level detection device 200 instead of the water level detection device 10. The water level detection device 200 comprises a pair of electrodes 202 and 204 and a control device. The control device has the same configuration as the control device 40. Hereinafter, the control device of this embodiment will be referred to as the control device 240. The pair of electrodes 202 and 204 are arranged in an electrically insulated state. The pair of electrodes 202 and 204 are positioned so that they are not submerged in the water in the bowl 6b when there is no blockage in the toilet device 6.

[0077] The flushing abnormality detection process in this embodiment is started at the same timing as the flushing abnormality detection process in the first embodiment. In the flushing abnormality detection process, the control device 240 determines whether or not to conduct electricity between the pair of electrodes 202 and 204. Specifically, the control device 240 applies a voltage to electrode 202 and identifies the current flowing between electrodes 202 and 204. When a drainage abnormality occurs in the toilet device 6 due to a blockage, the water level in the bowl 6b rises, and the pair of electrodes 202 and 204 are submerged in water. As a result, when the pair of electrodes 202 and 204 are submerged in water, electricity is conducted between the pair of electrodes 202 and 204 via the water.

[0078] When the control device 240 detects that current is flowing between the pair of electrodes 202 and 204, it prohibits cleaning, similar to S54. This prevents a situation where cleaning water is supplied when the water level in bowl 6b is high.

[0079] The control device 240 may perform the same processing as in S56. Following the processing in S56, the control device 240 determines whether or not to energize the pair of electrodes 202 and 204. The control device 240 repeats this determination until energization is no longer conducted between the pair of electrodes 202 and 204, and once energization is no longer conducted between the pair of electrodes 202 and 204, it may perform the same processing as in S62 and S64.

[0080] (Third embodiment) As shown in Figure 9, the flush toilet 100 of this embodiment is equipped with a water level detection device 300 instead of the water level detection device 10. The water level detection device 300 comprises a distance measuring sensor 302 and a control device. The control device has the same configuration as the control device 40. Hereinafter, the control device of this embodiment will be referred to as the control device 340. The distance measuring sensor 302 is attached to the toilet seat 6s. The distance measuring sensor 302 emits ultrasonic waves toward the bottom surface of the bowl 6b. The distance measuring sensor 302 receives ultrasonic waves reflected from the water surface of the bowl 6b. The control device 340 determines the distance between the distance measuring sensor 302 and the water surface of the bowl 6b using the period from when the distance measuring sensor 302 emits ultrasonic waves until when it receives them.

[0081] The control device 340 stores reference distances Dt1, Dt2, Dt3, and Dt4 in advance. Reference distance Dt1 corresponds to the same water level as the water level specified by the reference pressure Th1. Reference distance Dt2 corresponds to the same water level as the water level specified by the reference pressure Th2. Reference distance Dt3 corresponds to the same water level as the water level specified by the reference pressure Th3. Reference distance Dt4 corresponds to the same water level as the water level specified by the reference pressure Th4. Similar to the control device 40, the control device 340 uses each of the reference distances Dt1 to Dt4 depending on the timing of detecting the distance to the water surface, and performs an abnormality detection process to detect the occurrence of a drainage abnormality in the toilet device 6.

[0082] (Anomaly detection process during cleaning performed by control device 340) The cleaning abnormality detection process in this embodiment is started at the same timing as the cleaning abnormality detection process in the first embodiment. The same processes as the cleaning abnormality detection process in the first embodiment are indicated by the same reference numerals as in Figure 7. As shown in Figure 10, the cleaning abnormality detection process executes the process in S3. If it is determined that a predetermined period has elapsed since the cleaning water was supplied to the bowl 6b immediately before the reception signal was received (YES in S3), the process proceeds to S304. If the predetermined period has not elapsed since the cleaning water was supplied to the bowl 6b immediately before the reception signal was received (NO in S3), the process proceeds to S305.

[0083] In S304, the control device 340 detects that the distance to the water surface detected by the distance measuring sensor 302 (hereinafter referred to as "detected distance") exceeds the reference distance Dt2 (between timings T3 and T4). In S305, the control device 340 detects that the detected pressure exceeds the reference distance Dt3 (between timings T3 and T4).

[0084] In S304, if the detection distance exceeds the reference distance Dt2 (YES in S304), proceed to S54. Similarly, in S305, if the detection distance exceeds the reference distance Dt3 (YES in S305), proceed to S54.

[0085] If, in S304, the detection distance does not exceed the reference distance Dt2 (NO in S304), or if, in S305, the detection distance does not exceed the reference distance Dt3 (NO in S305), the control device 340 proceeds to S10. After the processing in S10, in S320, the control device 340 detects that the detection distance exceeds the reference distance Dt4 (between timings T4 and T6). If the detection distance exceeds the reference distance Dt4 (YES in S320), the control device 340 proceeds to S52. As a result, the amount of washing water supplied is reduced.

[0086] If the detection distance does not exceed the reference distance Dt4 (NO in S320), in S330, the control device 340 detects that the detection distance exceeds the reference distance Dt3 (between timings T8 and T10). If the detection distance exceeds the reference distance Dt3 (YES in S330), the control device 340 proceeds to S52. As a result, the amount of washing water supplied is reduced.

[0087] If the detection distance does not exceed the reference distance Dt3 (NO in S330), proceed to S32. If YES in S32, in S340, the control device 340 detects that the detection distance exceeds the reference distance Dt2 (between timings T11 and T12). If the detection distance does not exceed the reference distance Dt2 (NO in S340), proceed to S42. If the detection distance exceeds the reference distance Dt2 (YES in S340), proceed to S54. After processing in S54 and S56 is completed, in S360, the control device 340 detects that the detection distance falls below the reference distance Dt1. If the detection distance does not fall below the reference distance Dt1 (NO in S360), the control device 340 repeats the process in S360 until the detection distance falls below the reference distance Dt1. If the detection distance falls below the reference distance Dt1 (YES in S360), the processes in S62 and S64 are executed, and the cleaning abnormality detection process is terminated.

[0088] In this embodiment, the water level detection device 300 does not require purging when detecting the water level.

[0089] (Fourth Embodiment) As shown in Figure 11, the flush toilet 100 of this embodiment is equipped with a water level detection device 400 instead of the water level detection device 10. The water level detection device 400 comprises a pair of electrodes 402 and 404 and a control device. The control device has the same configuration as the control device 40. Hereinafter, the control device of this embodiment will be referred to as the control device 440. The pair of electrodes 402 and 404 are attached to the back surface of the bowl 6b of the toilet body 6m. Each of the pair of electrodes 402 and 404 has a conductive flat plate shape. Each of the pair of electrodes 402 and 404 is attached in a shape that conforms to the mounting surface of the toilet body 6m.

[0090] The control device 440 detects the capacitance of the pair of electrodes 402 and 404. The control device 440 detects the capacitance of the pair of electrodes 402 and 404 when a predetermined potential difference is applied between the pair of electrodes 402 and 404.

[0091] The control device 440 stores reference capacities Ec1, Ec2, Ec3, and Ec4 in advance. Reference capacities Ec1 correspond to the same water level as specified by reference pressure Th1. Reference capacities Ec2 correspond to the same water level as specified by reference pressure Th2. Reference capacities Ec3 correspond to the same water level as specified by reference pressure Th3. Reference capacities Ec4 correspond to the same water level as specified by reference pressure Th4. Similar to the control device 40, the control device 340 performs an abnormality detection process to detect the occurrence of a drainage abnormality in the toilet device 6 by using each reference capacities Ec1 to Ec4 depending on the timing of detecting the distance to the water surface.

[0092] (Anomaly detection process during cleaning performed by control device 440) The cleaning abnormality detection process in this embodiment is started at the same timing as the cleaning abnormality detection process in the third embodiment. The cleaning abnormality detection process in this embodiment is the same as the cleaning abnormality detection process in the third embodiment. However, in S304, the control device 440 detects that the capacitance of the detected pair of electrodes 402 and 404 (hereinafter referred to as "detected capacitance") exceeds the reference capacitance Ec2. In S305, the control device 440 detects that the detected capacitance exceeds the reference capacitance Ec3. In S320, the control device 440 detects that the detected capacitance exceeds the reference capacitance Ec4. In S330, the control device 440 detects that the detected capacitance exceeds the reference capacitance Ec3. In S340, the control device 440 detects that the detected capacitance exceeds the reference capacitance Ec3. In S360, the control device 440 detects that the detected capacitance exceeds the reference capacitance Ec1. Other processes of the cleaning abnormality detection process in this embodiment are the same as those of the cleaning abnormality detection process in the third embodiment.

[0093] (Fifth embodiment) As shown in Figure 12, the flush toilet 100 of this embodiment is equipped with a water level detection device 500 instead of the water level detection device 10. The water level detection device 500 comprises a float 502 and a control device. The control device has the same configuration as the control device 40. Hereinafter, the control device of this embodiment will be referred to as the control device 540. The float 502 is housed in the rear water passage 21. The float 502 floats on the water in the rear water passage 21. The float 502 moves vertically according to the water level in the rear water passage 21. When the float 502 comes into contact with the upper surface of the rear water passage 21, it transmits a signal to the control device 540.

[0094] The abnormality detection process during cleaning in this embodiment is started at the same timing as the abnormality detection process during cleaning in the first embodiment. During the abnormality detection process during cleaning, the control device 540 determines whether or not to receive a signal from the float 502. If the control device 540 receives a signal from the float 502, it prohibits cleaning, as in S54. This prevents a situation where cleaning water is supplied when the water level in the bowl 6b is high.

[0095] The control device 540 may perform the same processing as in S56. Following the processing in S56, the control device 540 determines whether or not a signal is being received from the float 502. The control device 240 repeats this determination until no more signals are received from the float 502, and when no more signals are received, it may perform the same processing as in S62 and S64.

[0096] The specific examples of the technology disclosed herein have been described in detail above. These are merely illustrative examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. Modifications of the above embodiments are listed below.

[0097] (Modification 1) In the water level detection device 10, the tip portion 14c of the internal portion 14b of the second detection pipe 14 does not have to be located in the left-side water passage 22. For example, the tip portion 14c of the second detection pipe 14 may be located inside the flush pipe 4 or in the bowl 6b.

[0098] (Modification 2) In the water level detection device 10, the tip portion 14c may be located in at least one of the rear water channel 21 and the right water channel 24. In another modification, the rim water channel 20 may branch further downward in addition to the left water channel 22 and the right water channel 24. In this modification, the tip portion 14c may be located in the water channel that has branched downward. The rim water channel 20 does not need to branch.

[0099] (Modification 3) In the water level detection device 10, the internal portion 14b of the second detection pipe 14 may be fixed to the outer wall of the toilet bowl body 6m located above the left water passage 22 by penetrating the outer wall of the toilet bowl body 6m, and positioned in the left water passage 22. In yet another modification, the internal portion 14b may be fixed to the outer wall of the toilet bowl body 6m located above the rear water passage 21 by penetrating the outer wall of the toilet bowl body 6m, and positioned in the rear water passage 21 by penetrating the storage space 30.

[0100] (Modification 4) The toilet bowl body 6m does not need to have a storage space 30.

[0101] (Modification 5) In the water level detection device 10, the internal portion 14b of the second detection pipe 14 may be fixed to the outer wall of the toilet bowl body 6m located to the left of the left-side water passage 22 by penetrating the outer wall of the toilet bowl body 6m located to the left of the left-side water passage 22, and then positioned in the left-side water passage 22.

[0102] (Modification 6) The water level detection device 10 may detect the water level by measuring the weight of the toilet bowl body 6m. In this case, a weight sensor may be placed below the toilet bowl body 6m. The control device 40 may perform flushing abnormality detection processing using a plurality of weight thresholds.

[0103] (Modification 7) In the water level detection device 10, the control device 40 may perform a purge process as appropriate. For example, the control device 40 may perform a purge process periodically regardless of whether or not washing water is supplied. The control device 40 may perform a purge process for a longer period of time at a predetermined timing after the start of washing water supply (for example, 59 seconds later) compared to other timings. The control device 40 may perform a larger number of purge processes at the above-mentioned predetermined timing compared to other timings. At the above-mentioned predetermined timing, the supply of washing water may have ended and the water level may have stabilized.

[0104] (Modification 8) The water level detection device 10 may detect the pressure while performing a purge at the time of water level detection.

[0105] (Modification 9) The water level detection device 10 may be capable of obtaining information indicating that the blockage has been cleared. For example, the control device 40 may be electrically connected to a blockage clearing button operated by the user when the blockage is cleared by the user. When the blockage clearing button is operated by the user, the control device 40 may perform a purge process and water level detection.

[0106] (Modification 10) The flushing pipe 4 that supplies flushing water to the toilet bowl body 6m may extend from outside the toilet bowl body 6m into either the left water passage 22 or the right water passage 24. In this case, the second detection pipe 14 in the water level detection device 10 may extend from outside the flushing pipe 4 into either the left water passage 22 or the right water passage 24.

[0107] (Modification 11) In the water level detection device 10, the second detection tube 14 may be bent downwards such that its tip portion 14c faces downwards. For example, the tip portion 14c may be bent at an angle of 5° or more with respect to the portion of the second detection tube 14 that is connected to the tip portion 14c. This can suppress the formation of a water film on the tip portion 14c.

[0108] (Example 12) In the water level detection device 10, the inner diameter of the tip portion 14c of the second detection tube 14 may be larger than the inner diameter of the other parts of the second detection tube 14. This can suppress the formation of a water film on the tip portion 14c.

[0109] (Example 13) In the water level detection device 10, a support member for supporting the second detection pipe 14 may be fixed to the rim water channel 20. The second detection pipe 14 may be attached to the toilet body 6m during construction.

[0110] (Variation 14) In the water level detection device 10, the opening and closing speed of the flapper valve in the tank 2 may be reduced. By suppressing pressure fluctuations in the rim water channel 20, the formation of a water film in the second detection pipe 14 can be suppressed.

[0111] (Variation 15) In the water level detection device 10, the control device 40 may perform the cleaning abnormality detection process using the reference pressure Th2, without using at least one of the reference pressures Th1, Th3, and Th4. In this case, in the cleaning abnormality detection process shown in Figure 9, the control device 40 does not need to perform at least one of the processes S4, S20, and S60 in which an unused reference pressure is used among the reference pressures Th1, Th3, and Th4. The control device 40 may also perform at least one of the processes S4, S20, and S60 in which an unused reference pressure is used among the reference pressures Th1, Th3, and Th4, using the reference pressure Th2. The same applies to the second to fifth embodiments.

[0112] (Variation 16) The water level detection device 10 may include an outside air pressure sensor located outside the bowl 6b that detects the atmospheric pressure outside the toilet device 6. The pressure sensor 11 and the outside air pressure sensor may be capable of detecting absolute pressure. The control device 40 may detect the water level using the pressure detected by the pressure sensor 11 and the outside air pressure sensor. With this configuration, it is possible to avoid situations in which the water level is not properly detected due to fluctuations in the pressure detected by the pressure sensor 11 caused by external factors such as atmospheric pressure and temperature. The pressure sensor 11 and the outside air pressure sensor may be housed in a single package.

[0113] (Example 17) In the first embodiment, the control device 40 may adjust at least one of the reference pressures Th1, Th2, Th3, and Th4, taking into account the operating environment and aging of the flush toilet 100, by detecting the pressure when no abnormality occurs in the water level at at least one of periodic and irregular timings. Similarly, in other embodiments, the reference volume, reference distance, etc., may be adjusted.

[0114] (Example 18) The suppression device may have a configuration that combines at least two of the first to fifth embodiments described above.

[0115] (Modification 19) In the cleaning abnormality detection process, the control device 40 does not have to execute the process in S5. In this case, the control device 40 may execute the process in S10 if NO is detected in S3. If a predetermined period has not elapsed since the cleaning water was supplied to the bowl 6b immediately before (NO in S3), the water level in the bowl 6b may be high even though no blockage has occurred. In this modification, by skipping the water level detection before the supply of cleaning water, it is possible to avoid a situation where cleaning water is not supplied even though no blockage has occurred.

[0116] The technical elements described herein or in the drawings demonstrate technical utility individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical utility. [Explanation of symbols]

[0117] 2: Tank, 4: Flushing pipe, 6: Toilet assembly, 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, 20: Rim water passage, 21: Rear water passage, 22: Left side water passage, 24: Right side water passage, 40: Control device, 60: Management terminal, 100: Flush toilet

Claims

1. A water level detection unit that detects the water level in the bowl of the toilet unit, The system includes a control unit for controlling the water level detection unit, The control unit, The supply timing is acquired at which a signal for supplying flushing water to the toilet device is obtained. A water level detection device that, when the supply timing is obtained, causes the water level detection unit to perform a first water level detection process to detect the water level before the flushing water is supplied to the toilet device.

2. The water level detection device according to claim 1, wherein the control unit causes the water level detection unit to perform a second water level detection process to detect the water level in the bowl of the toilet device when a supply timing is obtained in which a signal to supply new flushing water to the toilet device is obtained during the period from the start of supplying flushing water to the toilet device to a period in which the water level in the bowl is higher than when flushing water is not supplied.

3. The water level detection device according to claim 2, wherein the control unit detects the water level in the bowl in accordance with the change in the water level of the washing water in the bowl due to the supply of the washing water in the second water level detection process.

4. The control unit, In the first water level detection process, if a water level exceeding the first reference water level is detected, the supply of the flushing water to the toilet device is prohibited. The water level detection device according to claim 2 or 3, wherein in the second water level detection process, when a water level exceeding the first reference water level is detected, the flushing water is supplied to the toilet device.

5. The control unit, In the first water level detection process, if a water level exceeding the first reference water level is detected, the output unit is instructed to output information indicating that an abnormality has occurred in the water level in the bowl. The water level detection device according to any one of claims 2 to 4, wherein in the second water level detection process, if a water level exceeding a second reference water level that is higher than the first reference water level is detected, the output unit outputs information indicating that an abnormality has occurred in the water level in the bowl.

6. The water level detection device according to claim 5, wherein the control unit further causes the output unit to output information indicating that the water in the bowl is overflowing when a water level exceeding a third reference water level, which is higher than the second reference water level, is detected.

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