JP7675611B2 - Water level determination device and flush toilet - Google Patents

Description

The technology disclosed in this specification relates to a water level determination device and a flush toilet.

Patent document 1 discloses a system that uses a capacitance sensor to prevent toilet overflow. In this system, the water level in the bowl of the toilet body is determined by detecting the capacitance between two conductive plates attached to the outer surface of the outer wall of the toilet body.

Special Publication No. 2020-525690

When water in the bowl overflows from the toilet body, the area around the toilet body becomes dirty. In order to prevent the water in the bowl from overflowing from the toilet body, it is necessary to properly determine the water level in the bowl. This specification provides a novel technology for determining the water level in the bowl of the toilet body.

The water level determination device disclosed in this specification may include a pressure detection unit that detects pressure, and a water level determination unit that determines the water level in the bowl of the toilet device using the detected pressure.

Details and further improvements of the technology disclosed in this specification are explained in the "Description of Embodiments" below.

FIG. 1 shows a side view of a flush toilet according to an embodiment. FIG. 2 is a rear perspective view of the flush toilet according to the embodiment. 1 is a cross-sectional view taken at the center in the left-right direction of a toilet apparatus according to an embodiment of the present invention. 4 shows a cross-sectional view taken along line IV-IV in FIG. 5 shows an enlarged view of the area surrounded by the dashed line V in FIG. 4. 6 shows an enlarged view similar to FIG. 5 of an end face of a second sensing tube of a second embodiment. 7 shows a cross-sectional view taken along line VII-VII in FIG. FIG. 8 shows an enlarged view of the area enclosed by dashed line VIII in FIG. 9 is an enlarged view similar to FIG. 8 of an end face of a second sensing tube according to a third embodiment; 1 is a block diagram showing a schematic configuration of a water level detection device; 4 shows a graph of the pressure detected by the pressure sensor. 4 shows a flowchart of a process executed by a control device.

First Embodiment
(Outline of the configuration of the flush toilet 100: Figs. 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 includes a toilet device 6, a tank 2, and a water level detection device 10. The toilet device 6 includes a toilet body 6m and a flush pipe 4. The toilet body 6m is made of ceramic. The toilet body 6m includes a bowl 6b that receives waste. The tank 2 stores flush water for flushing the bowl 6b. The toilet device 6 includes a flush button (not shown) electrically connected to the tank 2. When the flush button is operated by a user, a motor drive device built into the tank 2 opens a flapper valve (not shown) arranged on the bottom surface of the tank 2, and flush water in the tank 2 is supplied to the bowl 6b via the flush pipe 4. As a result, the flush water washes away waste in the bowl 6b. In the toilet device 6, flush water in the tank 2 may be supplied to the bowl 6b by operating a lever arranged on the toilet device 6 in addition to operating the flush button. The flush button may be arranged on a remote controller electrically connected either wired or wirelessly to the tank 2. The flush water in the tank 2 may be supplied to the bowl 6b even without any operation by the user. For example, when the user is not detected by the sensor, the flush water in the tank 2 may be supplied to the bowl 6b.

Hereinafter, the direction in which the tank 2 and the toilet device 6 are lined up is referred to as the front-rear direction. In the front-rear direction, the side on which the toilet device 6 is arranged relative to the tank 2 is referred to as the front side in the front-rear direction, and the side on which the tank 2 is arranged relative to the wall 9 is referred to as the rear side in the front-rear direction. The horizontal direction perpendicular to the front-rear direction is referred to as the left-right direction. In the left-right direction, the back side of the paper in FIG. 1 is referred to as the right side, and the front side of the paper in FIG. 1 is referred to as the left side. In other words, the left and right directions correspond to the left and right as seen by a user facing the flush toilet 100. The vertical direction perpendicular to the front-rear direction is referred to as the up-down direction. In the up-down direction, the side on which the tank 2 is arranged relative to the flush pipe 4 is referred to as the upper side, and the side on which the flush pipe 4 is arranged relative to the tank 2 is referred to as the lower side.

The toilet device 6 further includes a toilet seat 6s, a toilet lid 6c, a functional unit 6f, and a drain pipe 8. The toilet seat 6s and the toilet lid 6c are each connected to the toilet body 6m so as to be openable and closable. The functional unit 6f automatically opens the toilet lid 6c when the user approaches the flush toilet 100. The functional unit 6f may have functions such as local cleaning, hot air drying, and deodorizing functions. The 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. The toilet seat 6s and the toilet lid 6c are not shown in FIG. 2.

The tank 2, flush pipe 4, and water level detection device 10 are isolated by a wall 9 from the space in which the flush toilet 100 is placed. A user cannot see the part of the water level detection device 10 that is placed on the outside (i.e., the back side) of the toilet device 6. This improves the design of the flush toilet 100. It is possible to prevent a user from accidentally damaging or soiling the tank 2, flush pipe 4, and water level detection device 10 when cleaning, etc. An inspection hatch (not shown) that can be opened and closed is provided in the wall 9, and an operator performs maintenance on the tank 2, flush pipe 4, and water level detection device 10 through the inspection hatch in the wall 9.

The flush pipe 4 extends downward from the underside of the tank 2, then bends and extends forward to connect with the toilet body 6m. The flush water stored in the tank 2 is supplied to the toilet body 6m through 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, then bends and extends upward. A water supply solenoid valve 3 is disposed at the end of the water supply pipe 3s opposite the tank 2. As shown in FIG. 2, the water supply solenoid valve 3 is connected to the clean water pipe 5 through 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 can prevent the intrusion of foreign matter by taking in clean water through the filter-equipped stop valve 3f. 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 disposed in the tank 2. The ball tap is equipped with a float (not shown) that displaces vertically depending on the flush water level in the tank 2. When the flush water level in the tank 2 rises to a predetermined level, the float rises and closes the ball tap. This stops the supply of clean water to the tank 2. The 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 drops and the ball tap opens. As a result, clean water is supplied from the water supply pipe 3s into the tank 2.

(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. Figure 3 shows a cross-sectional view of the toilet apparatus 6 cut at the centre in the left-right direction of the toilet apparatus 6. The toilet seat 6s, toilet lid 6c and drain pipe 8 are omitted from 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.

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. The cleaning water in the tank 2 flows into the rim water passage 20 from the cleaning pipe 4. In the rim water passage 20, the cleaning water flows forward from the rear water passage 21, branches into each water passage 22, 24, and is sent into the bowl 6b. The cleaning water flows in a swirling manner along the inner surface of the bowl 6b. As a result, the inner surface of the bowl 6b is cleaned.

As shown in FIG. 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 that defines the upper end of the storage space 30 of the toilet body 6m. When a drainage abnormality occurs and the flush water in the bowl 6b is not discharged normally, the flush water level in the rim water passage 20 rises. When the flush water level exceeds the through hole 32, the flush water pushes the air in the storage space 30 through the through hole 32. The air in the storage space 30 is released outside the storage space 30 by opening the air vent valve. As a result, the flush water flows into the storage space 30. The flush water in the storage space 30 is temporarily stored. When a drainage abnormality occurs in the bowl 6b, the flush water can be temporarily stored in the storage space 30 to prevent the flush water from overflowing from the bowl 6b. When the wash water in the bowl 6b is discharged normally, even if the wash water level reaches the through hole 32, the wash water does not flow into the storage space 30 because the storage space 30 is a sealed space and contains air. Even if a small amount of wash water flows into the storage space 30, the wash water flows out of the storage space 30 through the through hole 32 as the wash water level drops. Therefore, the wash water is not stored in the storage space 30.

(Configuration of water level detection device 10: Figs. 2 and 10)
The configuration of the water level detection device 10 will be described with reference to Figures 2 and 10. As shown in Figure 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 rear side of the tank 2. The actual box is covered with a cover from the rear side. The cover is not shown in Figures 2 and 10.

The control device 40 controls the flush toilet 100. The control device 40 includes a hardware processor such as a CPU (short for Central Processing Unit), a RAM (short for Random Access Memory), and a ROM (short for Read Only Memory). When the control device 40 receives operation of the flush button, it opens a flapper valve (not shown) located on the bottom surface of the tank 2. This allows flush water in the tank 2 to be supplied to the toilet body 6m via the flush pipe 4.

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 of the second detection pipe 14 is placed 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. By making the second detection pipe 14 placed in the rim water passage 20 out 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 other than copper that is difficult for mold and bacteria to grow on, such as silver.

The first detection pipe 13 connects the three-way joint 17 and the pressure sensor 11. An air tank 15 is placed 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 perpendicular to the longitudinal direction of the first detection pipe 13. The pressure sensor 11 is a highly accurate micro-pressure sensor, so it is 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 the pressure sensor 11 capable of detecting minute pressure fluctuations, the air tank 15 suppresses the turbulence in the detected pressure, thereby preventing the pressure sensor 11 from making a false detection. Furthermore, by placing 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.

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

The pressure sensor 11 is a sensor that detects the pressure in 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 in the first detection tube 13. As a result, the resistance value of the strain gauge resistor changes. The pressure sensor 11 detects the pressure in 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 or a semiconductor diaphragm type, and may further be at least one of a quartz pressure sensor and a capacitance bridge type sensor.

The first detection pipe 13 is connected to the bowl 6b via the second detection pipe 14. When the water level in the bowl 6b rises, the tip of the second detection pipe 14 is blocked and the pressure in the second detection pipe 14 rises. As the pressure in the second detection pipe 14 rises, the pressure in the first detection pipe 13 also rises. Therefore, the detection value of the pressure sensor 11 fluctuates according to the water level in the bowl 6b.

As shown by the dashed lines in FIG. 10, the control device 40 is 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 the management terminal 60. The management terminal 60 is a terminal operated by the manager of the flush toilet 100, and is located, for example, in the management company of the building in which the flush toilet 100 is installed. The control device 40 transmits the usage status, drainage status, etc. 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 a mobile terminal, PC, etc. owned by at least one of the user of the flush toilet 100 and the cleaning company.

(Detailed structure of the second detection tube 14: FIGS. 3 to 9)
3, the second detection pipe 14 penetrates the outer wall of the flush pipe 4 via the joint 16 and extends forward. The second detection pipe 14 has an internal portion 14b disposed inside the toilet apparatus 6 and an external portion 14a disposed outside the toilet apparatus 6. The internal portion 14b of the second detection pipe 14 passes inside the flush pipe 4 and is disposed in the rim water passage 20 of the toilet body 6m.

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 device external part 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, three-way joint 17), can be positioned so that the user cannot access them. 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 misalignment and damage of 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.

As shown in FIG. 4, the inside-device portion 14b bends leftward (i.e., downward in the plane of FIG. 4) at the rear water passage 21 and extends through the left water passage 22. The tip portion 14c of the inside-device portion 14b is located in the left water passage 22. An opening is provided on the end face 18 of the tip portion 14c, which connects the inside-device portion 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) through the first detection pipe 13. When a drainage abnormality occurs and the flush water level rises to the left water passage 22, the opening on 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 through the first detection pipe 13.

The higher the level of the cleaning water in the bowl 6b, the greater the amount of cleaning water located above the end surface 18. The higher the level of the cleaning water in the bowl 6b, the greater the pressure in the second detection tube 14 and the first detection tube 13. In other words, the level of the cleaning water in the 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 the bowl 6b by using the pressure in the second detection tube 14 and the first detection tube 13.

The water level detection device 10 places the second detection pipe 14 in the left water passage 22 that supplies flushing water to the bowl 6b, and uses the pressure in the second detection pipe 14 to determine the flushing water level in the bowl 6b. Therefore, there is no need to secure a separate space in the toilet device 6 for placing the second detection pipe 14. As a result, the water level in the bowl 6b can be detected without significantly changing the structure of the toilet device 6, for example, by placing the second detection pipe 14 in the left water passage 22 of an existing toilet device 6. The water level detection device 10 can be installed in a general-purpose toilet device 6.

Because foreign matter such as dirt is present in the bowl 6b and trap section along with the flushing water, the detected water level is affected by the foreign matter. As a result, the detected water level becomes unstable. In this embodiment, the tip portion 14c of the second detection tube 14 is disposed in the rim water passage 20, thereby preventing the detected water level from being affected by the foreign matter.

In the flush water in the rim water passage 20, turbulence occurs in the rear water passage 21 before branching, which receives flush water flowing in from the flush pipe 4. The turbulence of the flush water is suppressed from the rear water passage 21 toward the left and right side water passages 22, 23. By placing the tip portion 14c of the second detection pipe 14 in the left water passage 22 after branching, the pressure of the second detection pipe 14 due to the flow of flush water can be suppressed. This allows the flush water level in the bowl 6b to be properly detected.

The device interior portion 14b is disposed within the rim water passage 20 and is therefore covered by the outer wall of the toilet body 6m that defines the rim water passage 20. This makes it possible to prevent dirt from adhering to the device interior portion 14b. For example, when cleaning the bowl 6b, the tip portion 14c can be prevented from coming into contact with a cleaning tool, which can cause at least one of the following: displacement of the tip portion 14c and damage to the tip portion 14c.

As shown in FIG. 7, each water passage 22, 24 branches out and extends to the left and right sides of the upper edge of the bowl 6b. The second detection pipe 14 has a leg 19. The leg 19 extends from the lower end of the second detection pipe 14 toward the bottom surface 28 of the left water passage 22. The lower end of the leg 19 abuts the bottom surface 28. As a result, as shown in FIG. 8, the end surface 18 of the second detection pipe 14 is disposed above and away from the bottom surface 28. Cleansing water may remain on the bottom surface 28 of the left water passage 22. When the cleaning water remaining on the bottom surface 28 flows in from the opening of the end surface 18 of the second detection pipe 14, even if the opening is not completely blocked, a water film may be generated due to the surface tension between the surface of the flowing in cleaning water and the inner surface of the second detection pipe 14. When the opening of the end surface 18 of the second detection pipe 14 is covered by the water film, the pressure inside the second detection pipe 14 increases. By positioning the end face 18 of the second detection tube 14 above and away from the bottom face 28, it is possible to prevent cleaning water remaining on the bottom face 28 from flowing into the second detection tube 14 through the opening of the end face 18 of the second detection tube 14.

(Purge process: FIG. 10)
When flush water is supplied to the bowl 6b, the flush water passes through the left water passage 22 while being mixed with the air in the flush water passage. The flush water may enter the inner peripheral surface of the tip portion 14c due to the influence of a large pressure change that occurs when flush water is supplied to the bowl 6b, and multiple layers of water and air may be generated. As a result, the flush water that has entered the second detection tube 14 may form a water film 72 that blocks the second detection tube 14. If the second detection tube 14 is blocked by the water film 72, pressure may not be transmitted even if the water level in the bowl 6b has reached the second detection tube 14. In this case, the control device 40 cannot accurately detect the flush water level in the bowl 6b using the pressure value detected by the pressure sensor 11.

As shown in FIG. 10, the 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. The control device 40 operates the pump 50 and simultaneously opens the air solenoid valve 52. This causes air 70 to be pumped to 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 layer of air in the second detection pipe 14 to the left water passage 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 makes it possible to suppress the formation of the water film 72 in the second detection pipe 14. As a result, it is possible to suppress the influence of the water film 72 and the layer of air in the second detection pipe 14 on the detection pressure. The air solenoid valve 52 may be replaced with a check valve.

(Pressure change during cleaning: Figure 11)
With reference to Figure 11, the change in pressure inside the first detection pipe 13 and the second detection pipe 14 during the flush period Tc will be described. The flush period Tc is the period from when the flush button operation is accepted at timing T1, when flush water is supplied, until the supply of flush water ends. The flush period Tc includes the time required for the flush water to be drained after the supply of flush water ends and for the pressure detected by the pressure sensor 11 to become sufficiently stable. The flush period Tc is, for example, about 20 seconds, and is set in advance by the manufacturer of the flush toilet 100 depending on the capacity of the tank 2 and bowl 6b, etc.

(Normal pressure change)
First, using the solid line waveform W1, we will explain the pressure (hereinafter sometimes referred to as the detected pressure) in the first detection pipe 13 and the second detection pipe 14 when the toilet body 6m can normally discharge flushing water (hereinafter sometimes referred to as the normal state).

During the period before the flush button is operated at timing T1, flush water does not pass through the left water passage 22. Therefore, the detected pressure is maintained at a value close to the atmospheric pressure Ap.

When the control device 40 accepts 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 pressure peak P1.

After that, at timing T5, the flapper valve (not shown) of tank 2 is opened, and the supply of cleaning water to bowl 6b begins. This causes the level of cleaning water in tank 2 to drop. As a result, the float of the ball tap drops, the ball tap is opened, and new clean water is supplied to tank 2 from water supply pipe 3s (see Figure 1). As a result, the new clean water supplied to tank 2 is also supplied to bowl 6b as cleaning water. This allows a large amount of cleaning water to wash away dirt in bowl 6b.

When the supply of wash water to the bowl 6b begins, the wash water flows into the left water passage 22. At that time, the wash water blocks the opening of the end face 18 of the second detection tube 14. As a result, the detection pressure increases. While the wash water is being supplied, the amount and pressure of the wash water are high immediately after the start of the supply of wash water, and then the amount and pressure of the wash water gradually decrease.

After the supply of cleaning water begins at timing T5, the control device 40 operates the pump 50 again at timing T7. The pump 50 pressurizes air into the second detection pipe 14. After a predetermined time has elapsed since the pump 50 was operated, the pump 50 is stopped. As a result of this operation, the detected pressure rises again instantaneously, as shown by pressure peak P2.

After that, the cleaning water continues to flow into the 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 in the tank 2 flows into the bowl 6b, the float connected to the flapper valve falls along with the cleaning water level in the tank 2. This causes the flapper valve to close at timing T9. This stops the supply of cleaning water from the tank 2 to the bowl 6b. As a result, the detected pressure gradually decreases while repeatedly rising and falling.

After the flapper valve is closed, the cleaning water remaining in the cleaning pipe 4 and rim water passage 20 is sent into the bowl 6b, and the detected pressure gradually stabilizes and is maintained at atmospheric pressure Ap, and cleaning ends at timing T10. The control device 40 operates the pump 50 again at timing T10, and after a predetermined time has elapsed, stops operation of the pump 50. This causes the detected pressure to rise instantaneously, as shown by pressure peak P3. Thus, during the cleaning period Tc, the detected pressure under normal conditions changes at each timing, as shown by waveform W1, and is ultimately maintained at atmospheric pressure Ap.

(Pressure change when drainage abnormality occurs)
Using the thin dashed waveform W2 and the thick dashed waveform W3, a change in the detected pressure when a drainage abnormality occurs in the toilet device 6 will be described. Below, a drainage abnormality that occurs in the toilet device 6 will be described in two stages: a first drainage abnormality indicated by the waveform W2, and a second drainage abnormality indicated by the waveform W3.

The situation is different when the first drainage abnormality occurs and when the second drainage abnormality occurs. When the first drainage abnormality occurs, the water level in the bowl 6b is at a normal water level, and foreign objects are clogged in the drainage path in the bowl 6b and the drainage path downstream of the bowl 6b, narrowing the drainage path compared to normal, causing the water level to rise. The drainage path downstream of the bowl 6b includes the drain pipe 8 and, for example, a drain pipe (not shown) in the building in which the flush toilet 100 is installed. When the second drainage abnormality occurs, the water level in the bowl 6b has already risen above the normal water level, and even if a smaller amount of flush water is supplied to the bowl 6b than when the first drainage abnormality occurs, the detection pressure rises. When the second drainage abnormality occurs, as when the first drainage abnormality occurs, foreign objects are clogged in the drainage path in the bowl 6b and the drainage path downstream of the bowl 6b, narrowing the drainage path compared to normal, causing the water level to rise.

(Pressure change during first drainage abnormality)
As can be seen by comparing the waveforms W1 and W2, the detected pressure during the first drainage abnormality is approximately the same as the detected pressure during the normal state described above during the period from timing T1 to T7. During the first drainage abnormality, the amount of flush water passing through the left water passage 22 when flush water is supplied is the same as during normal times. However, during the first drainage abnormality, the amount of flush water discharged per unit time is lower than during normal times, so the water level in the bowl 6b does not drop as much as during normal times. As shown in the waveform W2, the detected pressure during the first drainage abnormality is higher than the detected pressure during normal times after timing T7. Even if the flapper valve is closed at timing T9, the opening of the tip portion 14c of the second detection pipe 14 is blocked by the water in the bowl 6b, so the detected pressure during the first drainage abnormality does not drop to atmospheric pressure Ap. The amount of flush water supplied to the bowl 6b during one flush is smaller than the capacity of the bowl 6b. Therefore, during the first drainage abnormality, the supply of flush water ends before the flush water overflows from the bowl 6b. After timing T10, the detected pressure during the first drainage abnormality is maintained at a pressure slightly lower than the detected pressure that rose when flush water was supplied at timing T5.

(Pressure change during the second drainage abnormality)
During the second drainage abnormality, flush water is further supplied to the bowl 6b when the water level in the bowl 6b has risen to the vicinity of the rim water passage 20 (for example, during the first drainage abnormality). During the second drainage abnormality, when flush water is supplied to the bowl 6b, the water level in the bowl 6b continues to rise. For this reason, as shown in the waveform W3, the detected pressure during the second drainage abnormality is higher than the detected pressure during the first drainage abnormality. During the second drainage abnormality, the bowl 6b cannot accept the amount of flush water supplied to it during one flush, and flush water may overflow from the bowl 6b. The detected pressure during the second drainage abnormality is maintained at a value higher than the detected pressure during the first drainage abnormality.

The control device 40 detects the level of the flush water in the bowl 6b by comparing the detected pressure received from the pressure sensor 11 with the reference pressure. The control device 40 uses the detected pressure received from the pressure sensor 11 to determine the level of the flush water in the bowl 6b. As described above, the detected pressure changes depending on the level of the flush water in the bowl 6b. The control device 40 stores the reference pressures Th1, Th2, Th3, and Th4 in advance. The control device 40 executes an abnormality detection process to detect the occurrence of a drainage abnormality in the toilet device 6 by using each of the reference pressures Th1 to Th4 depending on the timing of detecting the pressure. In FIG. 11, the reference pressures Th1 to Th4 used by the control device 40 as a comparison target for the detected pressure at each timing are shown by thick lines. Note that the reference pressures Th1 to Th4 are values for distinguishing between normal and abnormal conditions, so values obtained by learning control that corrects variations in the shape of the toilet and variations in the construction state may be stored.

(Normal Abnormality Detection Process Executed by the Control Device 40)
When the flush toilet 100 is installed, the water level detection device 10 is started. When the water level detection device 10 is started, the control device 40 executes an abnormality detection process. The abnormality detection process includes a normal abnormality detection process and a flush abnormality detection process. In the normal abnormality detection process, the control device 40 detects that the pressure of the second detection pipe 14 exceeds the reference pressure Th2 immediately after accepting the operation of the flush button by the user and before the start of flushing. In the normal abnormality detection process, the control device 40 detects that the pressure of the second detection pipe 14 exceeds the reference pressure Th2 for a predetermined period after the supply of flush water. When flush 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 close to the atmospheric pressure Ap. In a situation where a drainage abnormality has occurred, if water is supplied into bowl 6b from a source other than tank 2, for example by supplying flushing water directly to bowl 6b from a bucket, the water level in bowl 6b may reach second detection pipe 14. In this case, the detection pressure rises. Reference pressure Th2 is set to a value that can detect a state in which the opening of 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 in a situation in which water is supplied to bowl 6b from a source other than tank 2.

(Washing Abnormality Detection Process Executed by the Control Device 40: FIG. 12)
In the cleaning abnormality detection process, the control device 40 executes the abnormality detection process using each of the reference pressures Th1 to Th4 during the cleaning period Tc. When the control device 40 accepts operation of the cleaning button (timing T1 in FIG. 11), the control device 40 starts the process in FIG. 12 due to receiving a signal indicating that the cleaning button operation has been accepted.

In S2, the control device 40 operates the pump 50 (timing T2 in FIG. 9), and after a predetermined time has elapsed, stops the operation of the pump 50. Next, in S4, the control device 40 detects that the detected pressure exceeds the reference pressure Th2 (between timings T3 and T4).

By processing S2 to S4, the control device 40 detects the water level in the bowl 6b after pumping air 70 (see FIG. 10) into the second detection tube 14 with the pump 50. The pressure sensor 11 can detect the detected pressure while suppressing the formation of a water film 72 on the inner surface of the second detection tube 14. As a result, the detected pressure of the pressure sensor 11 can be used to appropriately determine whether the opening of the tip portion 14c of the second detection tube 14 is blocked by the water in the bowl 6b.

As shown in FIG. 11, the reference pressure Th2 is a pressure higher than the atmospheric pressure Ap. The reference pressure Th2 is set to a value that allows detection of a state in which the opening of the second detection tube 14 is blocked by the cleaning water in the bowl 6b by comparing it with the detection pressure. The reference pressure Th2 is a pressure lower than the reference pressure Th3. At the timing when the reference pressure Th2 is used, operation of the cleaning button is accepted and cleaning water is about to be supplied from the tank 2.

If the detected pressure exceeds the reference pressure Th2 (YES in S4), proceed to S54. In this case, the control device 40 does not supply cleaning water to the bowl 6b. That is, when the detected pressure exceeds the reference pressure Th2, the control device 40 does not open the flapper valve even if the control device 40 accepts operation of the cleaning button from the user. That is, when the detected pressure exceeds the reference pressure Th2, the control device 40 does not start cleaning. This makes it possible to prevent cleaning water from being supplied to the bowl 6b where a drainage abnormality has occurred and the cleaning water level has already risen. It is possible to prevent cleaning water from overflowing from the bowl 6b.

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

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.

In S52, the control device 40 stops the water supply to the tank 2. Specifically, the control device 40 closes the water supply solenoid valve 3 (see FIG. 10). This stops the supply of clean water from the clean water pipe 5 to the tank 2. During flushing, in addition to the flush water originally stored in the tank 2, the clean water supplied from the clean water pipe 5 is also supplied to the bowl 6b via the tank 2 as flush water. If the detected pressure exceeds the reference pressure Th4 immediately after flush water supply (YES in S20), the water supply to the tank 2 is stopped, thereby reducing the amount of flush water supplied to the bowl 6b when a drainage abnormality occurs. As a result, overflow from the top end of the bowl 6b is prevented when a drainage abnormality occurs, and even if flush water overflows from the top end of the bowl 6b, the amount of overflowing flush water can be reduced. When the processing of S52 is completed, proceed to S54.

If the detected pressure does not exceed the clogging reference pressure Th4 (NO in S20), the control device 40 operates the pump 50 in S22 (timing T7 in FIG. 11) 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 water level in the bowl 6b from being erroneously determined to have risen.

At timings T5 to T7 immediately after the flush water passes through the left water passage 22, the opening of the tip portion 14c of the second detection pipe 14 is temporarily blocked by the flush water supplied from the tank 2 to the bowl 6b. Immediately after the start of the flush water supply (timing T5), the pressure of the flush water flowing through the rim water passage 20 is high. In this case, the detected pressure temporarily rises regardless of whether a drainage abnormality occurs. As shown in FIG. 11, the detected pressure immediately after the start of the flush water supply (timing T5) may be higher than the reference pressure Th3. If the detected pressure is compared with the reference pressure Th3 immediately after the start of the flush water supply, the control device 40 may execute the process of S52 even though the flush water level in the bowl 6b has not risen due to the occurrence of a drainage abnormality. As a result, the amount of flush water supplied is reduced. Immediately after the start of the flush water supply (between timings T4 and T6), the control device 40 compares the detected pressure with the 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 increase in pressure 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 largest during cleaning water supply. Therefore, if a drainage abnormality occurs, the water level in bowl 6b rises significantly. By using the reference pressure Th4, immediately after cleaning water supply starts, it is possible to detect a state in which the water level in bowl 6b rises significantly due to a drainage abnormality.

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. This reduces the amount of cleaning water supplied. Between timings T8 and T10, the supply of cleaning water from the 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 the tank 2 to the 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.

Between timings T8 and T10, time has passed since the start of the supply of cleaning water, and the supply amount and pressure of cleaning water are lower than immediately after the start of the supply of cleaning water. For this reason, between timings T8 and T10, the pressure in the second detection tube 14 does not increase compared to immediately after the start of the supply of cleaning water (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 state 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 supply of cleaning water.

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 cleaning water is continuously supplied to the bowl 6b without reducing the supply amount, the 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.

If the detected pressure does not exceed the clogging 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 between timing T9 and timing T10 when the flapper valve is closed, during which flush water supplied from the tank 2 is sent to the bowl 6b and until flush water stops flowing in the rim water passage 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 of 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).

When the drainage period has elapsed (YES in S32), in S34, the control device 40 operates the pump 50 (timing T10) and stops the operation of the pump 50 after a predetermined time has elapsed. 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 FIG. 11) has elapsed. If the predetermined period Ta has not elapsed (NO in S42), the control device 40 executes the process of 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 ends the process in FIG. 12. Note that the predetermined period Ta may not be set, and the control device 40 may detect that the pressure exceeds the reference pressure Th2 until cleaning is started.

The control device 40 detects that the detected pressure exceeds the reference pressure Th3 while flushing water is being supplied (between timings T8 and T10), and detects that the detected pressure exceeds a reference pressure Th2 that is lower than the reference pressure Th3 during the specified period Ta (between timings T11 and T12). During the specified period Ta, the control device 40 detects the occurrence of a drainage abnormality using the reference pressure Th2 that is lower than the reference pressure Th3. 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.

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 accepts operation of the cleaning button, it does not open the flapper valve. Even if the control device 40 accepts operation of the cleaning button, cleaning water in the tank 2 is not supplied to the bowl 6b.

When 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, when the detected pressure exceeds the reference pressure Th3 (YES in S30), even if the cleaning button is operated for a predetermined period of time, the cleaning water in the tank 2 is not supplied to the bowl 6b. When the detected pressure exceeds the reference pressure Th3, the level of cleaning water in the bowl 6b is high, and there is a high possibility that the cleaning water will overflow from the upper end of the bowl 6b. When a second drainage abnormality occurs, which is even more likely to overflow from the upper end of the bowl 6b, the control device 40 executes a process to change the amount of cleaning water supplied. This makes it possible to prevent the cleaning water from overflowing from the upper end of the bowl 6b when the second drainage abnormality occurs. After stopping the water supply to the tank 2 in S52, the control device 40 closes the flapper valve of the tank 2 (i.e., the supply of cleaning water in the tank 2 to the bowl 6b is stopped), and after a predetermined time has elapsed, opens the water supply solenoid valve 3 again. In a modified example, the control device 40 may execute a process to change the amount of cleaning water supplied by forcibly closing the flapper valve during cleaning.

If the detected pressure exceeds the reference pressure Th2 (YES in S40), the supply of cleaning water from the tank 2 to the bowl 6b has already ended, and the process of reducing the amount of cleaning water supplied to the bowl 6b is not executed. If the detected pressure exceeds the reference pressure Th2 (YES in S40), cleaning water in the tank 2 is not supplied to the bowl 6b even if the cleaning button is operated for a specified period of time.

Next, in S56, the control device 40 notifies the management terminal 60 (see FIG. 10) of the occurrence of a drainage abnormality. This allows the manager of the flush toilet 100 to recognize the occurrence of a drainage abnormality. 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 of S60 until the detected pressure is below the reference pressure Th1. As shown in FIG. 11, the reference pressure Th1 is a pressure slightly higher than the atmospheric pressure Ap. The reference pressure Th1 is set to a value that can detect a state in which the opening of the second detection pipe 14 is exposed from the flush 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 flush water in the bowl 6b is located below the second detection pipe 14, i.e., that the drainage abnormality has been resolved.

For example, if the level of flush water in the bowl 6b drops and the detected pressure falls below the reference pressure Th1 (YES in S60) due to at least one of the following: a drainage abnormality caused by a clogged toilet paper is naturally resolved in a relatively short time, or the drainage abnormality is resolved by the manager, then in S62 the control device 40 cancels the prohibition on flushing in S54. By detecting the elimination of the drainage abnormality in the process of S60 and canceling the prohibition on flushing in the process of S62, the control device 40 can avoid continuing the prohibition on flushing for a drainage abnormality that has already been resolved. After that, in S64, the control device 40 notifies the management terminal 60 that the drainage abnormality has been resolved, and ends the flushing abnormality detection process. This allows the manager of the flush toilet 100 to recognize that the drainage abnormality has been resolved.

(Effects of this embodiment)
In the water level detection device 10, the water level in the bowl 6b is detected by the pressure sensor 11. The pressure sensor 11 has a higher accuracy in detecting the water level in the bowl 6b while flush water is being supplied than other sensors such as a float sensor, a capacitance sensor, an ultrasonic sensor, etc. Therefore, the water level detection device 10 can detect the water level in the bowl 6b more accurately than configurations that detect the water level by other sensors.

If dust or other foreign matter adheres to the opening of the end face 18 of the internal device portion 14b from the outside, the pressure in the second detection pipe 14 and the pressure in the left water passage 22 may not match. In this case, even if the pressure in the second detection pipe 14 is detected by the pressure sensor 11, the pressure in the left water passage 22 cannot be accurately determined. In the above-mentioned flush toilet 100, the internal device portion 14b of the second detection pipe is arranged in the left water passage 22 of the toilet device 6, so that it is possible to prevent foreign matter from adhering to the internal device portion 14b. In other words, the accuracy of water level detection can be improved compared to a configuration in which the internal device portion 14b is arranged outside the toilet device 6. By arranging the external device portion 14a and each component of the water level detection device 10, which have little effect on the pressure detection accuracy, outside the toilet device 6, the space occupied by the water level detection device 10 in the toilet device 6 can be reduced, and the size of the toilet device 6 can be reduced.

As described above, the water level detection device 10 detects the occurrence of a drainage abnormality by comparing the detected pressure at each of the multiple timings during the cleaning period Tc with multiple reference pressures Th1 to Th4. Therefore, the water level detection device 10 can detect the occurrence of a drainage abnormality even during the cleaning period Tc when cleaning water is being supplied and the water level in the bowl may change.

(Second embodiment; FIG. 6)
As shown in Fig. 5, the end face 18 of the tip portion 14c of the second detection pipe 14 in the first embodiment is formed perpendicular to the direction in which the tip portion 14c extends. This improves the manufacturing efficiency of the second detection pipe 14. As shown in Fig. 6, the end face 18 in the second embodiment is formed at an incline with respect to the direction in which the tip portion 14c extends. The internal portion 14b is disposed so that the end face 18 is approximately perpendicular to the front-rear direction. The end face 18 is disposed parallel to the opening 26 located on the bowl 6b side of the left water passage 22. With this configuration, compared to a configuration in which the end face 18 is disposed at an incline with respect to the opening 26, the rise in the water level of the bowl 6b can be detected more accurately by the detected pressure of the pressure sensor 11.

(Third embodiment; FIG. 9)
As shown in Figure 9, the end face 18 of the second detection pipe 14 abuts against the bottom surface 28 of the left water passage 22. The second detection pipe 14 does not have legs 19. As a result, when the flush water level reaches the bottom surface 28 of the left water passage 22, the flush water begins to block the opening of the end face 18 of the second detection pipe 14. When the flush water level is low, the opening of the end face 18 is likely to be blocked by the flush water. This allows the control device 40 to detect the water level in the bowl 6b at a relatively early stage after the flush water level starts to rise.

(Correspondence)
The pressure sensor 11 is an example of a "pressure detection unit." The control device 40 is an example of a "water level determination unit." The water level detection device 10 is an example of a "water level determination device." The first detection pipe 13 and the second detection pipe 14 are an example of a "communicating pipe."

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 given above. Modifications of the above embodiments are listed below.

(Variation 1) The pressure sensor 11 does not have to detect the pressure in the second detection pipe 14 and the first detection pipe 13. For example, the pressure sensor 11 may be disposed on the bottom surface 28 of the left water passage 22 and detect the pressure value of the flush water in the left water passage 22. The pressure sensor 11 may transmit the detected pressure value in the left water passage 22 to the control device 40 either wirelessly or by wire. In this variation, the "communication pipe" can be omitted.

(Variation 2) The water level detection device 10 does not need to include the pump 50, the purge pipe 12, the air solenoid valve 52, and the air pipe 54.

(Variation 3) The control device 40 may not need to compare the detected pressure with the reference pressure after operating the pump 50 and pumping air into the first detection pipe 13 and the second detection pipe 14. For example, the control device 40 may operate the pump 50 at a predetermined cycle and stop the operation after a predetermined time has elapsed. For example, the control device 40 may not need to execute at least one of the processes S2, S22, and S34 in the cleaning abnormality detection process.

(Variation 4) Instead of air, the pump 50 may pump at least one fluid, for example a gas other than air and a liquid, into the first detection tube 13 and the second detection tube 14.

(Variation 5) The tip portion 14c of the device internal portion 14b of the second detection pipe 14 does not have to be positioned in the left water passage 22. For example, the tip portion 14c of the second detection pipe 14 may be positioned in the cleaning pipe 4 or in the bowl 6b.

(Variation 6) The tip portion 14c may be located in at least one of the rear water passage 21 and the right water passage 24. In another variation, the rim water passage 20 may further branch downward in addition to the left water passage 22 and the right water passage 24. In this variation, the tip portion 14c may be located in the water passage that branches downward. The rim water passage 20 does not have to branch.

(Variation 7) The second detection pipe 14 may not have a leg 19. For example, the tip portion 14c of the second detection pipe 14 may partially abut the bottom surface 28 at the rear and bend upward at the front. This allows the end surface 18 to be held at a position spaced above the bottom surface 28. In another variation, the second detection pipe 14 may be positioned spaced above the bottom surface 28 by being suspended from the top surface of the left water passage 22. Furthermore, the second detection pipe 14 may be positioned spaced above the bottom surface 28 by being fixed to either the left or right wall of the left water passage 22.

(Variation 8) The pressure sensor 11 may be disposed inside the toilet device 6. In other words, the second detection pipe 14 does not have to penetrate the outer wall of the flush pipe 4 and be disposed from the rim water passage 20 to the outside of the toilet device 6.

(Variation 9) The control device 40 does not need to execute at least one of the normal abnormality detection process and the cleaning abnormality detection process.

The technical elements described in this specification or drawings have 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 can achieve multiple objectives simultaneously, and achieving any one of those objectives is itself technically useful.

2: Tank, 3: Water supply solenoid valve, 4: Flush pipe, 6: Toilet device, 6b: Bowl, 6m: Toilet body, 10: Water level detection device, 11: Pressure sensor, 12: Purge pipe, 13: First detection pipe, 14: Second detection pipe, 14a: External part of device, 14b: Internal part of device, 14c: Tip part, 18: End face, 19: Leg, 20: Rim water passage, 21: Rear water passage, 22: Left water passage, 24: Right water passage, 26: Opening, 28: Bottom, 30: Storage space, 32: Through hole, 40: Control device, 50: Pump, 52: Air solenoid valve, 60: Management terminal, 70: Air, 72: Water film, 100: Flush toilet, Ta: Predetermined period, Tc: Flush period, Th1, Th2, Th3, Th4: Reference pressure

Claims (13)

A pressure detection unit that detects pressure;
a water level determining unit that determines a water level in a bowl of the toilet device using the detected pressure ,
A water level determining device , wherein the pressure detection unit detects the pressure above a trap unit that discharges water from the bowl . A communication pipe communicating with the bowl is further provided.
The water level determining device according to claim 1 , wherein the water level determining unit determines the water level of the bowl by using a pressure in the communicating pipe. The water level determination device according to claim 2, further comprising a pump that pumps fluid into the communication pipe. The water level determination device according to claim 3, wherein the water level determination unit determines the water level of the bowl after the pump pumps the fluid into the connecting pipe. The water level determination device according to claim 3 or 4, wherein the fluid is air. The water level determination device according to any one of claims 2 to 5, wherein the tip portion of the communication pipe is disposed in a rim water passage that delivers cleaning water to the bowl. The rim water passage branches to the left and right sides of the upper edge of the bowl,
The water level identifying device according to claim 6 , wherein the tip portion is disposed downstream of a branch point. The water level determination device according to claim 7, wherein the end face of the tip portion is arranged parallel to an opening located at the end of the rim water passage on the bowl side. The water level determination device according to any one of claims 6 to 8, wherein the lower end of the tip portion abuts against the bottom surface of the rim water passage. The water level determination device according to any one of claims 6 to 9, wherein the end face of the tip portion is positioned above and away from the bottom surface of the rim water passage. The pressure detection unit is disposed outside the toilet device,
The water level identifying device according to any one of claims 6 to 10, wherein the communication pipe penetrates an outer wall of the toilet device and extends from the outside of the toilet device to the rim water passage. The water level determination device according to any one of claims 1 to 11, wherein the water level determination unit determines the water level of the bowl while cleaning water is being supplied to the bowl. A flush toilet comprising the water level identifying device according to any one of claims 1 to 12 and the toilet device.

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