Water-washable toilet

Abstract

To provide a siphon jet flush toilet capable of preventing water splashing by air that is trapped in a jet waterway which is ejected from a jet spout water port for pushing out washing water even if the seal water level falls below the specified seal water level.SOLUTION: A siphon jet flush toilet 1 includes: a drain trap pipe 8 with a top that regulates the seal water level, which is located between an ascending pipe and a downstream pipe; a jet spout water port 14 that spouts washing water towards the entrance of the drain trap pipe; a water tank 4 that stores washing water supplied to the jet spout water port; a jet waterway 16 for guiding the washing water from the water tank to the jet spout water port; a controller that controls rim spout water and jet spout water: and a water level sensor that detects the position of sealing water. The jet spout water port is located in the sealing water, which is arranged so that, when the position of sealing water W1 is lower than the predetermined seal water level, adds washing water to a bowl to increase the position of sealing water, and jets the spout water in this state.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a flush toilet, and more particularly to a siphon jet type flush toilet. [Background technology]

[0002] Conventionally, siphon jet flush toilets have been known in which water is supplied directly from the water mains to the rim spout, and flush water is directed to the jet spout from a low-height water storage tank using head pressure, as described in Patent Document 1. Also known is a siphon jet flush toilet in which front rim spouting, middle rim spouting, and rear rim spouting are performed consecutively, and jet water spouting is performed during middle rim spouting (sequential control), as described in Patent Document 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5180295 [Patent Document 2] Japanese Patent Application Publication No. 2023-32964 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the flush toilet of Patent Document 1, the tank is positioned to have a low silhouette, and jet water is directed into the jet water conduit by the head pressure of the flush water in the tank. In this flush toilet, flush water is directed into the jet water conduit by a relatively weak head pressure, so the flow rate of the flush water discharged from the jet spout is slow, and the force of pulling into the drain trap pipe due to siphon action is small. As a result, clogging with waste or the like can cause the water seal position to drop below the specified water seal level. When flush water is discharged from the jet spout with the water seal position lowered, air that has accumulated in the jet water conduit is ejected from the jet spout, pushing out the flush water and causing splashes. The flush toilet of Patent Document 2 also has the same problem of water splashing as the toilet of Patent Document 1.

[0005] Therefore, the present invention was made to solve the problems (issues) associated with conventional technology, and aims to provide a siphon jet flush toilet that allows air accumulated in the jet water conduit to be ejected from the jet spout, pushing out the flush water and preventing splashing, even when the water seal position drops below a specified water seal level. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a siphon jet flush toilet, comprising: a bowl portion having a waste receiving surface and a rim portion formed along the upper edge of the waste receiving surface, wherein a seal water having a predetermined seal water level is formed at the bottom of the bowl portion; a rim spout formed in the rim portion for spouting flush water into the bowl portion; a drain trap pipe connected to the bottom of the bowl portion, comprising an ascending pipe extending upward from below the bowl portion, a descending pipe extending downward from the ascending pipe, and a drain trap pipe having a top located between the ascending pipe and the descending pipe and defining the seal water level; and a drain trap pipe connected to the inlet of the drain trap pipe. The device has a jet water outlet arranged below the bowl section so as to discharge flush water toward the bowl section, a water storage tank for storing flush water to be supplied to the jet water outlet, a jet water conduit connecting the water storage tank to the jet water outlet and guiding the flush water in the water storage tank to the jet water outlet, a control device for controlling rim water outlet that discharges flush water from the rim water outlet and jet water outlet that discharges flush water from the jet water outlet, and a detection means for detecting the water seal position, the jet water outlet is located within the water seal, and when the water seal position is lower than a predetermined water seal level, flush water is supplied to the bowl section to raise the water seal position to the water seal level, and in this state, jet water is discharged. For example, if a large amount of waste is clogged and discharged, and the siphon breaks after flush water is replenished into the water tank, the water seal position may drop. If the jet is discharged from the jet spout while the water seal position is lowered, the air trapped in the jet waterway will be ejected from the jet spout, pushing out the flush water and causing splashes. According to the present invention, when the water sealing position is lower than a predetermined water sealing level, cleaning water (sealing water) is replenished into the bowl section to raise the water sealing position, and jet water is discharged in this state, so that air accumulated in the jet water conduit is ejected from the jet water discharge port, pushing out the cleaning water and preventing water splashing.

[0007] In the present invention, the detection means for detecting the water seal position is preferably a water level sensor provided in the jet water conduit. According to the present invention configured as described above, the water seal position is directly detected by the water level sensor, so that the water seal position can be detected accurately.

[0008] In the present invention, the detection means for detecting the water seal position is preferably a tank water level detection means for detecting the water level of the water storage tank, and the water seal position is estimated from the value of the dead water level, the value of the stopped water level, or the time required to supply water to the water storage tank until the stopped water level is reached, detected by this tank water level detection means. According to the present invention configured as described above, the water seal position is estimated using the existing tank water level detection means, so there is no need to provide a new detection sensor or the like.

[0009] In the present invention, the tank water level detection means is preferably a float switch that detects the still water level of the water storage tank. According to the present invention configured as described above, the water seal position is estimated using the existing flow and switch, so there is no need to provide a new detection sensor or the like.

[0010] In the present invention, preferably, before jet water spouting is performed, rim water spouting is performed to replenish seal water. According to the present invention configured in this manner, the bowl surface of the bowl section can be cleaned by performing rim water spraying before jet water spraying, and further, the cleaning water from this rim water spraying can be used to replenish the sealing water.

[0011] In the present invention, it is preferable that the water storage tank further has an overflow pipe for discharging flush water from the water storage tank into the jet water conduit when the time required to supply water to the water storage tank for the water level to rise to the stop water level becomes long, and flush water is replenished into the water storage tank, and this flush water is made to flow out of the overflow pipe into the jet water conduit to replenish sealing water. According to the present invention configured in this manner, the existing overflow pipe can be used to replenish the seal water, thereby simplifying the mechanism for replenishing the seal water.

[0012] In the present invention, preferably, cleaning water is supplied to the bowl portion to raise the water seal position to near a predetermined water seal level. According to the present invention configured in this manner, when the sealing water position is lower than the specified sealing water level, cleaning water (sealing water) is replenished in the bowl section to raise the sealing water position to near the specified sealing water level, and jet water is discharged in this state, so that air accumulated in the jet water conduit is sprayed out from the jet water discharge port, pushing out the cleaning water and preventing water splashing. [Effects of the Invention]

[0013] With the siphon jet flush toilet of the present invention, even if the water seal position drops below a specified water seal level, air trapped in the jet water conduit is ejected from the jet water outlet, pushing out the flush water and preventing splashing. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a plan view showing a flush toilet according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a side cross-sectional view taken along line II-II in FIG. [Figure 3] 10 is a time chart showing "rim spouting," "tank water supply," "jet spouting," and "tank water level" in a flush toilet according to an embodiment of the present invention. [Figure 4A] 10 is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" during a large flush of a flush toilet according to an embodiment of the present invention. [Figure 4B] 10 is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" in a small-flush mode of a flush toilet according to an embodiment of the present invention. [Figure 5] FIG. 1 is a side cross-sectional view of a flush toilet showing a state in which the water seal position is lower than a predetermined water seal level. [Figure 6] This is a graph obtained through experiments showing the relationship between the water seal position (water seal depth) and the average number of water droplets (water splashes) when the water seal position is lower than a specified water seal level. [Figure 7] FIG. 2 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention. [Figure 8A] A diagram showing the instantaneous flow rate of flush water discharged from the rim spout during a large flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water discharged from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe. [Figure 8B] This is a diagram showing the instantaneous flow rate of flush water discharged from the rim spout during a small flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water discharged from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe. DETAILED DESCRIPTION OF THE INVENTION

[0015] A flush toilet according to an embodiment of the present invention will now be described with reference to the drawings. First, the basic structure of a flush toilet according to this embodiment will be explained using Figures 1 and 2. Figure 1 is a plan view showing a flush toilet according to an embodiment of the present invention, and Figure 2 is a side cross-sectional view taken along line II-II in Figure 1.

[0016] As shown in Figures 1 and 2, the flush toilet 1 according to this embodiment is a siphon jet type flush toilet. This flush toilet 1 comprises a ceramic toilet body 2, a resin toilet seat and toilet lid (not shown) placed on the top surface of the toilet body 2, and a water storage tank 4 placed at the upper rear of the toilet body 2 and covered by a resin cover (not shown).

[0017] The toilet body 2 is formed with a bowl portion 6 for receiving waste, a drain trap pipe 8 provided at the bottom of the bowl portion 6 for discharging waste by siphon action, a rim spout 10 for rim water discharge, a rim water conduit 12 for guiding flushing water to the rim spout 10, a jet spout 14 for jet water discharge, and a jet water conduit 16 for guiding flushing water to the jet spout 14.

[0018] Bowl portion 6 has a bowl-shaped waste receiving surface 18, a rim portion 20 formed along the upper edge of bowl portion 6, and a shelf portion 21 formed between waste receiving surface 18 and rim portion 20. Bowl portion 6 also has a pot portion 22 formed in the area below waste receiving surface 18 and connected to drain trap pipe line 16. A water sealing surface (water collecting surface) W is formed inside pot portion 22.

[0019] The drain trap pipeline 8 has an inlet 8a, an ascending pipeline 8b extending upward from the inlet 8a, a descending pipeline 8c extending downward from the ascending pipeline 8b, and a top 8d located between the descending pipeline 8c and the ascending pipeline 8b and determining the sealing water level of the sealing surface W. Here, the lower end of the descending pipe 8c of the drain trap pipe 8 is connected to a drain pipe (not shown) via a drain socket (not shown).

[0020] When viewing the toilet body 2 from the front, the rim spout 10 is formed on the left rear side of the rim portion 20. The rim spout 10 spouts flush water forward, and this flush water flows down onto the waste receiving surface 18 while swirling around the inner circumferential surface of the rim portion 20 and the shelf surface of the shelf portion 21, thereby cleaning the waste receiving surface 18.

[0021] The rim conduit 12 is formed in a tapered shape, with the flow path cross section gradually becoming smaller towards the rim spout 10. A water supply hose 23 that is directly connected to the water supply is connected to the upstream side of the rim conduit 12. Flush water is supplied to the rim conduit 12 from the water supply, and is discharged from the rim spout 10 by the water supply pressure of the water supply.

[0022] Jet water outlet 14 is formed in the bottom of bowl portion 6. Jet water outlet 14 is positioned opposite inlet 8a of drain trap pipe 8 and is directed towards inlet 8a of drain trap pipe 8. Jet water outlet 14 ejects flush water towards inlet 8a of drain trap pipe 8, and this flush water flows into drain trap pipe 8, activating the siphon action. Furthermore, jet water outlet 14 is positioned so as to be located within the sealed water (accumulated water).

[0023] The jet water conduit 16 comprises an upstream flow path 16a extending forward from the water storage tank 4, a curved flow path 16b bending from this upstream flow path, and a downstream flow path 16c extending rearward from this curved flow path and connecting to the jet water spouting port 14. Flush water is supplied to the jet water conduit 16 from the water storage tank 4, and the flush water is spouted from the jet water spouting port 14 due to the head pressure of the flush water.

[0024] The water storage tank 4 is a gravity-fed tank that stores flush water to be used for jet spouting and supplies it to the jet spout 14. Flush water is stored in the water storage tank 4 up to a predetermined stop water level (WL0), and flush water from this stop water level to a predetermined dead water level (DWL) is used for jet spouting. The water storage tank 4 is a small resin tank. The lower part of the water storage tank 4 (the valve body of the drain valve 38, described below) is positioned below the top surface of the rim part 20 of the toilet body 2, and above the top 8d of the drain trap pipe 8. This makes the flush toilet 1 a low-profile toilet. The flush water source (flushing water supply device) that supplies flush water to the jet water outlet 14 is not limited to the gravity-fed water storage tank shown in this embodiment, but may also be configured to supply flush water from the storage tank to the jet water outlet 14 using a pressure pump.

[0025] Within the water storage tank 4 are provided a water supply device 24 that supplies flush water into the water storage tank 4, a drainage device 26 that supplies or stops the flush water stored in the water storage tank 4 to the jet water conduit 16, and a float switch 28 that detects when the flush water level in the water storage tank 4 has reached the stop water level (WL0). Note that instead of a float switch, the stop water level of the flush water in the water storage tank 4 may also be detected by a capacitance sensor, ultrasonic liquid level sensor, or the like. Furthermore, outside the water storage tank 4, there is provided a controller 29 that controls the water supply device 24 and the drainage device 26 to operate or stop based on an operation signal from the user, and an operation unit (not shown) that transmits an operation signal in response to the user's operation.

[0026] The water supply device 24 comprises a constant flow valve (not shown) connected to the water supply, a rim-side solenoid valve 30 that supplies or stops the flow of flush water to the rim spout 10, and a tank-side solenoid valve 34 that supplies or stops the flow of flush water to a tank water supply port 32 located inside the water storage tank 4. The rim-side solenoid valve 30 and the tank-side solenoid valve 34 are driven by commands from a controller 29 based on operation signals from the user and water level detection signals from a float switch 28.

[0027] The drainage device 26 includes an overflow pipe 36 that drains overflowing water from the water storage tank 4 into the toilet body, a drain valve 38 fixed to the lower end of the overflow pipe 36, and a toilet flushing unit 40 that opens and closes the drain valve 38 by moving the overflow pipe 36 up and down using an electric drive force. The overflow pipe 36 has open upper and lower ends. Therefore, if it takes a long time to supply water to the water storage tank 4 to raise the water level to the stop water level (WL0), the overflow pipe 36 will drain the overflowing water from the water storage tank 4 into the jet water conduit 16. A guide member 42 that guides the up and down movement of the drain valve 38 is attached to the periphery of the drain outlet 4a of the water storage tank 4. The toilet flushing unit 40 is driven by commands from the controller 29 based on an operation signal from the user.

[0028] The controller 29 is electrically connected to the operation unit, float switch 28, rim-side solenoid valve 30, tank-side solenoid valve 34, and toilet flushing unit 40, and is capable of sending and receiving various signals. The controller 29 receives a flush start signal for a large flush or small flush from the operation unit, and activates or stops the rim-side solenoid valve 30, tank-side solenoid valve 34, and toilet flushing unit 40 based on a pre-stored flush sequence.

[0029] Next, we will explain "rim water spouting," "tank water supply," "jet water spouting," and "tank water level" in a flush toilet 1 according to this embodiment with reference to Figure 3. Figure 3 is a time chart showing "rim water spouting," "tank water supply," "jet water spouting," and "tank water level" in a flush toilet according to an embodiment of the present invention.

[0030] Here, "rim water discharge" refers to the discharge of flush water from the rim water discharge port 10, "tank water supply" refers to the supply of water to the water storage tank 4, "jet water discharge" refers to the discharge of flush water from the jet water discharge port 14, and "tank water level" refers to the level of flush water in the water storage tank 4.

[0031] As shown in Figure 3, during a large flush of the flush toilet 1, first, after a standby state at time t0, when the user operates the operating part, the rim-side solenoid valve 38 turns ON at time t1, commencing rim spouting, in which water is supplied to the rim water conduit 12 and flush water is spouted from the rim spout 10. This rim spouting continues until time t5.

[0032] Next, at time t2, the drain valve 38 is opened and turned ON, and jet spouting begins, in which flush water in the water storage tank 4 passes through the jet water conduit 16 and is spouted from the jet spouting port 14. This jet spouting ends at time t4. While jet water spouting is taking place from time t2 to time t4, rim spouting is also taking place at the same time.

[0033] 3, for convenience, the rim spouting from time t1 when rim water spouting begins to time t2 when jet water spouting begins will be referred to as "front rim water spouting," the rim water spouting from time t2 when jet water spouting is performed to time t4 will be referred to as "middle rim water spouting," and the rim water spouting from time t4 when jet water spouting ends to time t5 when rim water spouting ends will be referred to as "rear rim water spouting." Also, as mentioned above, "jet water spouting" is performed from time t2 to time t4.

[0034] Next, as shown in Figure 3, at time t2 when jet water spouting began, the level of flush water in the water storage tank 4 was at the still water level so float switch 28 was ON, but at the subsequent time t3 the level of flush water in the water storage tank 4 drops below the still water level so float switch 28 turns OFF. This OFF state of float switch 28 continues until time t7.

[0035] Also, at time t6, tank-side solenoid valve 34 is opened and turned ON, and tank water supply to the water storage tank 4 begins, finishing at time t8. As this tank water supply begins at time t6, the flush water level in the water storage tank 4 rises, which causes float switch 28 to return to ON at time t7 as the flush water level in the water storage tank 4 rises to the stop water level, entering a full water state.

[0036] The large flush has been explained using Figure 3, but the time chart in Figure 3 also applies to the small flush. Note that, as will be described later, the large flush and small flush have different water discharge times and volumes.

[0037] Next, the water spouting times and water spouting volumes of rim spouting and jet water spouting in the large flush and small flush will be explained using Figures 4A and 4B. Figure 4A is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet water spouting" in the large flush of a flush toilet according to an embodiment of the present invention, and Figure 4B is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet water spouting" in the small flush of a flush toilet according to an embodiment of the present invention.

[0038] As shown in Figure 4A, in the case of large flush, the front rim water spouting time is 1.9 seconds (s) and the water spouting volume is 0.41 liters (L), the middle rim water spouting time is 2.4 seconds (s) and the water spouting volume is 0.52 liters (L), and the rear rim water spouting time is 6.1 seconds (s) and the water spouting volume is 1.32 liters (L). In addition, the jet water spouting time is 2.4 seconds (s) and the water spouting volume is 2.31 liters (L).

[0039] As is clear from Figure 4A, in the case of large flush, the water spouting time of the front rim water spout (1.9 seconds) is shorter than the water spouting time of the rear rim water spout (6.1 seconds). Furthermore, the total water spouting time of the front rim water spout and the middle rim water spout (1.9 seconds + 2.4 seconds) is shorter than the water spouting time of the rear rim water spout (6.1 seconds).

[0040] Similarly, as shown in Figure 4B, for a small flush, the front rim water spouting time is 1.4 seconds (s) and the water spouting volume is 0.31 liters (L), the middle rim water spouting time is 1.7 seconds (s) and the water spouting volume is 0.37 liters (L), and the rear rim water spouting time is 7.6 seconds (s) and the water spouting volume is 1.64 liters (L). Also, the jet water spouting time is 1.7 seconds (s) and the water spouting volume is 1.50 liters (L).

[0041] As is clear from Figure 4A, in the case of the small flush, as in the case of the large flush described above, the water spouting time of the front rim water spout (1.4 seconds) is shorter than the water spouting time of the rear rim water spout (7.6 seconds). Furthermore, the total water spouting time of the front rim water spout and the middle rim water spout (1.4 seconds + 1.7 seconds) is shorter than the water spouting time of the rear rim water spout (7.6 seconds).

[0042] Next, we will explain what happens when the water seal position in a flush toilet drops below a predetermined water seal level with reference to Figure 5. Figure 5 is a side cross-sectional view of a flush toilet showing the state in which the water seal position is lower than the predetermined water seal level. In the flush toilet 1, the seal water level is set with reference to the inlet 8a of the drain trap pipe 8, and is normally maintained at a predetermined seal water level (the position of the seal surface W in FIG. 2).

[0043] In a flush toilet 1, the water seal position is normally maintained at a predetermined water seal level (position W of the water seal surface), but in situations such as those described below, the water seal position W1 may fall below the water seal level, as shown in Figure 5. For example, when installing a toilet or turning on the power, flush water may not be supplied to the bowl, in which case the water seal position will be lowered. The water seal position will also be lowered if waste clogs the water supply pipe or drain trap pipe, causing the flush water to be drawn out for a long time due to the siphon effect. The water seal position may also be lowered when the power is turned on after the waste blockage is cleared. The water seal position will also be lowered if the amount of flush water supplied (refilled) to the bowl is simply low.

[0044] In this way, the inventors have discovered that when flush water is discharged from the jet water outlet 14 with the water seal position lowered below the specified water seal level, the air accumulated in the jet water conduit 16 is ejected from the jet water outlet 14, pushing out the flush water and causing water splashing. Therefore, the inventors conducted experiments to verify what kind of water sealing position would cause a lot of water splashing.

[0045] Fig. 6 is a diagram obtained through experiments showing the relationship between the water seal position (water seal depth) and the average number of water droplets (water splashes) when the water seal position is lower than a predetermined water seal level. In Fig. 6, the water seal position (water seal depth) is based on the upper end 8e of the inlet 8a of the drain trap pipe 8. As is clear from FIG. 6, it was verified that the largest number of water droplets were ejected when the water sealing position (water sealing depth) was near the upper end of the jet water spouting port 14.

[0046] Next, a method for detecting whether the water seal position has dropped below a predetermined water seal level will be described. First, a water level sensor 46 for detecting the water seal position is provided at one or more locations in the jet water conduit 16 (see FIG. 5), and this water level sensor 46 detects whether the water seal position has dropped below a predetermined water seal level.

[0047] Next, as described above, the water storage tank 4 is provided with a float switch 28 for detecting the water stop level (WL0). This float switch 28 can indirectly detect a drop in the water seal position from a change in the time it takes for water to be supplied to the water storage tank 4. That is, when the water seal position is at a predetermined water seal level, after jet water spouting has been performed, the water level in the water storage tank 4 drops to a predetermined dead water level (DWL). However, if, for example, waste is clogging the drain pipe or drain trap pipe 8 and the water seal position drops below the predetermined water seal level, the head pressure between the flush water level in the water storage tank and the water seal position increases, and a lot of flush water is discharged from the water storage tank during flushing, causing the water level to drop below the predetermined dead water level (DWL). When water supply to the water storage tank 4 is started from this state, the time it takes for the dead water level (DWL) to reach the stop water level (WL0) detected by the float switch 28 will be extended, causing a discrepancy with the normal water supply time. This discrepancy in water supply time (longer water supply time) makes it possible to detect a drop in the water seal position. In addition, a float switch may be provided to detect the dead water level (DWL), and this float switch may be used to detect when the dead water level has dropped below a predetermined dead water level, thereby detecting a drop in the seal water position.

[0048] As another example of detecting a lowering of the water seal position, a change in the inflow rate from the water source can be predicted from the time required for the water level to rise from the dead water level (DWL) to the stop water level (WL0) in the water storage tank 4. If it takes longer than usual for the water level to rise, in other words, if the water supply time is longer than usual, it is possible that the inflow rate from the water source has decreased. In such a case, the refill by the rear rim water discharge, which will be described later, will be insufficient, causing the water seal position to drop, and the lowering of the water seal position can be detected from the time it takes for the water level in the water storage tank to rise.

[0049] In the flush toilet 1 according to this embodiment, when it is detected that the water seal position has dropped below a predetermined water seal level, flush water is replenished into the bowl section 6 before jet water spouting is performed, and jet water spouting is performed with the water seal position returned to the predetermined water seal position. Replenishment of flush water into the bowl section 6 is carried out according to the first and second examples described below.

[0050] In the first example, the time from time t1 to time t2, which is the time for front rim water spouting shown in Figure 3, is made longer (time t1 is advanced) than in the normal case (when the water seal position is at a predetermined water seal level), and this longer time is used to increase the amount of flush water supplied to the bowl section 6 more than in the normal case, so that the lowered water seal position is returned to the predetermined water seal level. After this, jet water spouting begins at time t2.

[0051] In the second example, before jet water spouting begins at time t2 shown in Figure 3, the tank solenoid valve 34 is opened to supply flush water to the water storage tank 4, causing the water level in the water storage tank 4 to rise above the upper end of the overflow pipe 36. This causes flush water to flow into the overflow pipe 36 from its upper end, pass through the jet water conduit 16, and be replenished into the bowl section 6, with the water seal position returning to the specified water seal level. After this, jet water spouting begins.

[0052] Next, the flushing operation of a flush toilet according to an embodiment of the present invention will be explained with reference to Figure 7. Figure 7 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention.

[0053] 7(a) shows the standby state, in which flush water has accumulated in the bowl section 6 up to the seal water level W, and flush water has also accumulated in the jet water conduit 16 up to the same height as the seal water level. At this time, air is stagnating in part of the upstream flow path 16a located directly below the water storage tank 4.

[0054] Next, as shown in Figure 7(b), the rim-side solenoid valve 30 opens, rim spouting begins, and the flush water level gradually rises in the bowl section 6. In conjunction with this, the flush water level also gradually rises in the jet water conduit 16, and trapped air is expelled from the overflow pipe 36, filling the jet water conduit 16 with water.

[0055] After this, as shown in Figure 7(c), while rim water spouting continues, drain valve 38 opens and jet water spouting begins. At this time, the pooled water (sealing water) remaining in bowl section 6 and flush water from rim water spouting combine with flush water from jet water spouting, and a large flow of flush water flows into drain trap pipe 8, causing a powerful siphon action and discharging waste.

[0056] Next, as shown in Figure 7(d), while rim water spouting continues, the drain valve 38 closes. Even when the drain valve 38 closes, rim water spouting and jet water spouting flow into the drain trap pipe 8, so the siphon action can continue.

[0057] Thereafter, as shown in Figure 7(e), the flush water level in bowl section 6 drops as the accumulated water is discharged by siphon action, and air enters from the top of inlet 8a of drain trap pipe 8, ending the siphon action. Even after the siphon action ends, rim spouting continues and ends when flush water accumulates in bowl section 6 up to the seal water level. At this time, flush water has also accumulated in jet water conduit 16 up to the same height as the seal water level.

[0058] Next, as shown in Figure 7(f), the tank-side solenoid valve 34 opens and tank water supply begins. When the flush water level in the water storage tank 4 rises and the float switch 28 detects that the flush water level has reached the stop water level, the tank-side solenoid valve 27 closes, and then the system returns to its original standby state as shown in Figure 5(a).

[0059] Next, the instantaneous flow rate of flush water spouted from the rim spout during the large flush and small flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe will be explained with reference to Figures 8A and 8B. Figure 8A is a diagram showing the instantaneous flow rate of flush water spouted from the rim spout during the large flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe, and Figure 8B is a diagram showing the instantaneous flow rate of flush water spouted from the rim spout, the instantaneous flow rate of flush water spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe during the small flush of a flush toilet according to an embodiment of the present invention.

[0060] In Figures 8A and 8B, the dashed line indicates the instantaneous flow rate of flush water discharged from the jet water outlet 14, the dotted line indicates the instantaneous flow rate of flush water discharged from the rim water outlet 10, and the solid line indicates the instantaneous flow rate of flush water flowing into the inlet 8a of the drain trap pipe 8.

[0061] As shown in Figure 8A, during a large flush, at time t2 the drain valve 38 opens and flush water in the water storage tank 4 passes through the jet water conduit 17 and is discharged from the jet water spouting port 14. The instantaneous flow rate of the jet water spouting, shown by the dashed line, increases suddenly immediately after it starts and then remains approximately constant. At time t4 the drain valve 48 closes, and as a result the instantaneous flow rate of the jet water spouting also decreases.

[0062] The rim water spouting indicated by the dashed dotted line has a constant instantaneous flow rate and is also performed between time t2 and time t4 when jet water spouting is being performed. Furthermore, flush water discharged by the rear rim discharge during the previous flush remains in the bowl portion 6 as pooled water. Therefore, between time t2 and time t4, the flush water from the rim spout and the accumulated water remaining in the bowl section 6 due to the post-rim spout from the previous flush combine with the flush water from the jet spout, and a large flow of flush water flows into the inlet 8a of the drain trap pipe 8, as shown by the solid line.

[0063] As a result, in this embodiment, even if flush water is supplied to the jet water conduit 16 by the head pressure of the flush water in the low-profile water storage tank (although siphon action is unlikely to occur with this jet water spout alone), the flush water and accumulated water from the rim spout also flow into the inlet 8a of the drain trap pipe 8, so that a powerful siphon action can be used to reliably discharge waste.

[0064] After the drain valve 38 closes at time t4, the instantaneous flow rate of the jet water spouting decreases, but the rim water spouting continues at the same instantaneous flow rate. As a result, the instantaneous flow rate of flush water from the jet water spouting and rim water spouting decreases, but this allows the siphon action to continue. In this way, a strong siphon action can be generated without increasing the amount of water stored in the water storage tank 4, and furthermore, this siphon action can be continued, so that water conservation can be achieved.

[0065] Next, as shown in Figure 8B, in a small flush, at time t2 the drain valve 38 opens and flush water in the water storage tank 4 passes through the jet water conduit 17 and is spouted from the jet water spouting port 14. The instantaneous flow rate of the jet water spouting, shown by the dashed line, increases suddenly immediately after it starts and then remains approximately constant. At time t4 the drain valve 48 closes, which causes the instantaneous flow rate of the jet water spouting to also decrease.

[0066] The rim water spouting indicated by the dashed dotted line has a constant instantaneous flow rate and is also performed between time t2 and time t4 when jet water spouting is being performed. Furthermore, flush water discharged by the rear rim discharge during the previous flush remains in the bowl portion 6 as pooled water. For this reason, between time t2 and time t4, flush water from the jet spouting and rim spouting flows into the inlet 8a of the drain trap pipe 8. However, after time t4, the flush water from the rim spouting and the pooled water remaining in the bowl section 6 combine with the flush water from the jet spouting, and a large flow rate of flush water flows into the inlet 8a of the drain trap pipe 8, as shown by the solid line.

[0067] As a result, in this embodiment, even in the case of a small flush, even if flush water is supplied to the jet water conduit 16 by the head pressure of the flush water in the low-silhouette water storage tank (although siphon action is unlikely to occur with this jet water spout alone), the flush water and accumulated water from the rim spout also flow into the inlet 8a of the drain trap pipe 8, so that a strong siphon action can be used to reliably discharge waste.

[0068] Furthermore, after a strong siphoning action occurs, the instantaneous flow rate of flush water from the jet spouting and rim spouting decreases, but this allows the siphoning action to continue. In this way, even in the case of a small flush, a strong siphon action can be generated without increasing the amount of water stored in the water storage tank 4, and this siphon action can be continued, thereby achieving water conservation.

[0069] Next, the effects achieved by the flush toilet according to the embodiment of the present invention described above will be explained. First, the water seal position may drop if, for example, a large amount of waste clogging the drain and the siphon breaks after flush water is replenished into the water storage tank 4. When the water seal position is lowered and a jet is discharged from the jet water outlet 14, the air that has accumulated in the jet water conduit 16 is ejected from the jet water outlet 14, pushing out the flush water and causing splashes. With the flush toilet 1 of this embodiment, if the water seal position is lower than the specified water seal level, flush water (seal water) is replenished into the bowl section 6 to raise the water seal position, or to raise it to near the specified water seal level, and jet water is discharged in this state, so that air accumulated in the jet water conduit 16 is sprayed out from the jet water discharge port 16, pushing out the flush water and preventing water splashing.

[0070] Secondly, with the flush toilet 1 according to this embodiment, the water seal position is detected directly by the water level sensor 46, so the water seal position can be detected accurately.

[0071] Thirdly, with the flush toilet 1 according to this embodiment, the water seal position is estimated using tank water level detection means such as an existing float switch 28, so there is no need to install a new detection sensor or the like.

[0072] Fourth, with the flush toilet 1 of this embodiment, the bowl surface of the bowl section 6 can be cleaned by performing rim water spouting before jet water spouting, and furthermore, the flush water from this rim water spouting can be used to replenish the sealing water.

[0073] Fifth, with the flush toilet 1 of this embodiment, seal water can be replenished using the existing overflow pipe 36, making it possible to simplify the mechanism for replenishing seal water. [Explanation of symbols]

[0074] 1 flush toilet 2 Toilet body 4. Water tank 6 Bowl section 8 Drain trap pipe 8a entrance 8b Ascending pipe 8c descending pipe 8d top 10 Rim Spout 14 Jet outlet 16 Jet Waterway 18 Waste receiving surface 20 Rim 24 Water supply equipment 26 Drainage system 28 Float switch 29 Controller 30 Rim side solenoid valve 32 Tank water inlet 34 Tank side solenoid valve 36 Overflow pipe 38 Drain valve 40 Toilet flushing unit 46 Water level sensor W Water sealing surface (water storage surface) W1 Water sealing position WL0 Water stop level DWL dead water level

Claims

1. A siphon jet flush toilet, A bowl portion having a waste receiving surface and a rim portion formed along the upper edge of the waste receiving surface, wherein a water seal having a predetermined water seal level is formed in the lower part of the bowl portion; a rim spout formed in the rim portion for spouting flush water into the bowl portion; a drain trap pipe connected to the lower part of the bowl portion, the drain trap pipe having an ascending pipe extending upward from the lower part of the bowl portion, a descending pipe extending downward from the ascending pipe, and a top portion positioned between the ascending pipe and the descending pipe and defining the seal water level; a jet spout disposed below the bowl portion so as to spout flush water toward the inlet of the drain trap pipe; a water storage tank that stores flush water to be supplied to the jet water outlet; a jet water conduit that connects the water storage tank and the jet water outlet and guides the flush water in the water storage tank to the jet water outlet; a control device that controls rim spouting, which spouts flush water from the rim spout port, and jet spouting, which spouts flush water from the jet spout port; and a detection means for detecting the water seal position, The jet outlet is located within the water seal, When the water seal position is lower than the predetermined water seal level, flush water is replenished to the bowl section to raise the water seal position, and jet water is discharged in this state.

2. 2. The flush toilet according to claim 1, wherein the detection means for detecting the water seal position is a water level sensor provided within the jet water conduit.

3. A flush toilet as set forth in claim 1, wherein the detection means for detecting the water seal position is a tank water level detection means for detecting the water level of the water storage tank, and the water seal position is estimated from the value of the dead water level, the value of the stopped water level, or the time it takes to supply water to the water storage tank until the stopped water level is detected by this tank water level detection means.

4. 4. A flush toilet according to claim 3, wherein the tank water level detection means is a float switch that detects the still water level of the water storage tank.

5. 2. The flush toilet according to claim 1, wherein the seal water is replenished by performing rim water spouting before performing jet water spouting.

6. A flush toilet as set forth in claim 1, further comprising an overflow pipe within the water storage tank that discharges flush water from the water storage tank into the jet water conduit when the time required to supply water to the water storage tank for the water level in the water storage tank to rise to the stop water level becomes long, and flush water is replenished into the water storage tank, and this flush water is allowed to flow out of the overflow pipe into the jet water conduit to replenish seal water.

7. 2. The flush toilet according to claim 1, wherein flush water is supplied to the bowl portion to raise the water seal position to near a predetermined water seal level.

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