Flush 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 the rim spout is supplied with water directly from the water mains, and flush water is directed to the jet spout from a low-height water storage tank by 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 continuously, and jet water is spouted 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] JP 2023-32964 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the flush toilet of Patent Document 1, the tank is arranged with a low silhouette, and the jet water is directed to the jet water conduit by the head pressure of the flush water in the tank. In this flush toilet, flush water is directed to the jet water conduit by a relatively weak head pressure, so the flow rate of the flush water discharged from the jet water outlet is slow, and the force of pulling the flush water into the drain trap pipe due to siphon action is small. As a result, the water seal position may drop below the specified water seal level due to clogging with waste, etc. When flush water is discharged from the jet water outlet with the water seal position lowered, the air that has accumulated in the jet water conduit is ejected from the jet water outlet, pushing out the flush water and causing water splashing. 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 has been made to solve the problems (issues) associated with the conventional technology, and has as its object to provide a siphon jet type flush toilet that is capable of preventing air trapped in the jet water conduit from being ejected from the jet outlet, pushing out the flush water and causing water splashing, even when the water seal position falls 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 type 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, said bowl portion having a seal water having a predetermined seal water level formed at the lower part of said bowl portion, a rim spout formed in the rim portion for spouting flush water into the bowl portion, a drain trap pipe connected below said bowl portion, comprising an ascending pipe extending upward from below the bowl portion, a descending pipe extending downward from said ascending pipe, a drain trap pipe having a top located between said ascending pipe and the descending pipe and defining the seal water level, and an inlet of said drain trap pipe. The device has a jet water outlet arranged below the bowl portion so as to spray flushing water toward the face, a water storage tank for storing flushing water to be supplied to the jet water outlet, a jet water conduit connecting the water storage tank to the jet water outlet and directing the flushing water in the water storage tank to the jet water outlet, a control device for controlling the rim water outlet which sprays flushing water from the rim water outlet and the jet water outlet which sprays flushing 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, flushing water is replenished to the bowl portion to raise the water seal position to the water seal level, and in this state, jet water is sprayed. For example, if a large amount of waste is clogged and discharged, and the siphon breaks after flush water is replenished to the water tank, the water seal position may drop. If the jet is discharged from the jet outlet with the water seal position lowered, the air trapped in the jet water conduit will be ejected from the jet outlet, pushing out the flush water and causing water splashing. According to the present invention, when the sealing water position is lower than a predetermined sealing water level, cleaning water (sealing water) is replenished to the bowl section to raise the sealing water 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 thus configured, 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 sealing position is preferably a tank water level detection means for detecting the water level of the water storage tank, and the water sealing position is estimated based on the value of the dead water level, the value of the stop water level, or the time required to supply water to the water storage tank until the stop water level is reached, detected by this tank water level detection means. According to the present invention thus configured, 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 for detecting the stop water level of the water storage tank. According to the present invention configured as described above, the seal water 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, it is preferable to perform rim water spouting before performing jet water spouting, thereby replenishing 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 spouting before jet water spouting, and further, the cleaning water from this rim water spouting 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 in 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 caused to flow out of the overflow pipe into the jet water conduit to replenish sealing water. According to the present invention configured as described above, the seal water can be replenished using the existing overflow pipe, so that the mechanism for replenishing the seal water can be simplified.

[0012] In the present invention, preferably, cleaning water is supplied to the bowl portion to raise the water sealing position to near a predetermined water sealing level. According to the present invention configured in this manner, when the sealing water position is lower than a predetermined sealing water level, cleaning water (sealing water) is replenished to the bowl section to raise the sealing water position to near the predetermined 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. Effect of the Invention

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

[0014] [Figure 1] FIG. 1 is a plan view showing a flush toilet according to an embodiment of the present invention. [Diagram 2] 2 is a side cross-sectional view taken along line II-II in FIG. 1. [Diagram 3] 1 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] 1 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] 1 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 of a flush toilet according to an embodiment of the present invention. [Diagram 5] FIG. 2 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 seal water position (seal water depth) and the average number of water droplets (water splashes) when the seal water position is lower than a specified seal water 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] FIG. 1 is a diagram showing the instantaneous flow rate of flush water spouted 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 spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe. [Figure 8B] A diagram showing the instantaneous flow rate of flush water spouted 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 spouted 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 PREFERRED EMBODIMENTS

[0015] A flush toilet according to an embodiment of the present invention will be described below with reference to the drawings. First, the basic structure of a flush toilet according to this embodiment will be explained with reference to 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 of this embodiment is a siphon jet type flush toilet. This flush toilet 1 is equipped with a ceramic toilet body 2, a plastic toilet seat and toilet lid (not shown) placed on the top surface of this toilet body 2, and a water storage tank 4 placed at the upper rear of the toilet body 2 and covered by a plastic 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 water outlet 10 for rim water spouting, a rim water conduit 12 for guiding flushing water to the rim water outlet 10, a jet water outlet 14 for jet water spouting, and a jet water conduit 16 for guiding flushing water to the jet water outlet 14.

[0018] The bowl portion 6 comprises a bowl-shaped waste receiving surface 18, a rim portion 20 formed along the upper edge of the bowl portion 6, and a shelf portion 21 formed between the waste receiving surface 18 and the rim portion 20. The bowl portion 6 also comprises a pot portion 22 formed in the area below the waste receiving surface 18 and connected to the drain trap pipe 16. A water sealing surface (reservoir surface) W is formed inside the 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 looking at the toilet body 2 from the front, the rim spout 10 is formed on the rear left side of the rim portion 20. The rim spout 10 spouts flushing water forward, and this flushing water swirls around the inner circumferential surface of the rim portion 20 and the shelf surface of the shelf portion 21 before flowing down to the waste receiving surface 18 and cleaning the waste receiving surface 18.

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

[0022] The jet water outlet 14 is formed in the bottom of the bowl portion 6. The jet water outlet 14 is disposed opposite the inlet 8a of the drain trap pipe 8, and is directed toward the inlet 8a of the drain trap pipe 8. The jet water outlet 14 ejects flush water toward the inlet 8a of the drain trap pipe 8, and this flush water flows into the drain trap pipe 8, activating the siphon effect. The jet water outlet 14 is disposed so as to be located within the sealed water (pooled 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 outlet 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 outlet 14 by 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-silhouette type toilet. In addition, the flush water source (flush 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, and a pressure pump may be used to supply flush water from the storage tank to the jet water outlet 14.

[0025] Provided within the water storage tank 4 are a water supply device 24 which supplies flush water into the water storage tank 4, a drainage device 26 which supplies or stops the flush water stored in the water storage tank 4 to the jet water conduit 16, and a float switch 28 which detects when the flush water level in the water storage tank 4 has reached the stop water level (WL0). Note that the stop water level of the flush water in the water storage tank 4 may be detected by a capacitance sensor, ultrasonic liquid level sensor, or the like, other than the float switch. In addition, outside the water tank 4, there is provided a controller 29 that controls the water supply device 24 and the drainage device 26 to be driven or stopped 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 a water supply, a rim-side solenoid valve 30 which supplies or stops flush water to the rim spout 10, and a tank-side solenoid valve 34 which supplies or stops flush water to a tank water supply port 32 arranged in 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 an operation signal from the user or a water level detection signal 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 by an electric driving force. The overflow pipe 36 has both upper and lower ends open. 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 overflowing water from the water storage tank 4 is discharged to the jet water conduit 16 by the overflow pipe 36. 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 a command from the controller 29 based on an operation signal from the user.

[0028] The controller 29 is electrically connected to the operation unit, the float switch 28, the rim side solenoid valve 30, the tank side solenoid valve 34, and the 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 drives or stops the rim side solenoid valve 30, the tank side solenoid valve 34, and the toilet flushing unit 40 based on a flush sequence stored in advance.

[0029] Next, "rim water spouting," "tank water supply," "jet water spouting," and "tank water level" in a flush toilet 1 according to this embodiment will be explained 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 spouting" refers to spouting flush water from the rim spout 10, "tank water supply" refers to supplying water to the water storage tank 4, "jet spouting" refers to spouting flush water from the jet spout 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, at time t1 the rim-side solenoid valve 38 turns ON, commencing rim spouting, which supplies water to the rim water conduit 12 and spouts flush water 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 water spouting port 14. This jet water spouting ends at time t4. When jet water spouting is being performed from time t2 to time t4, rim water spouting is also being performed at the same time.

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

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

[0035] Also, at time t6, the tank-side solenoid valve 34 is opened and turned ON, starting tank water supply to the storage tank 4, and the tank water supply ends at time t8. As a result of this tank water supply starting at time t6, the flush water level in the storage tank 4 rises, which causes the float switch 28 to return to ON at time t7 as the flush water level in the 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 small flush also applies to the time chart in Figure 3. Note that, as will be described later, the large flush and small flush have different water discharge times and water discharge volumes.

[0037] Next, the spouting times and water spouting volumes of rim spouting and jet spouting in the large flush and small flush will be explained with reference to 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 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 spouting" in the small flush of a flush toilet according to an embodiment of the present invention.

[0038] As shown in Fig. 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). Also, 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 discharge time of the front rim water discharge (1.9 seconds) is shorter than the water discharge time of the rear rim water discharge (6.1 seconds). Furthermore, the total water discharge time of the front rim water discharge and the middle rim water discharge (1.9 seconds + 2.4 seconds) is shorter than the water discharge time of the rear rim water discharge (6.1 seconds).

[0040] Similarly, as shown in Figure 4B, in the case of 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 discharge time of the front rim water discharge (1.4 seconds) is shorter than the water discharge time of the rear rim water discharge (7.6 seconds). Furthermore, the total water discharge time of the front rim water discharge and the middle rim water discharge (1.4 seconds + 1.7 seconds) is shorter than the water discharge time of the rear rim water discharge (7.6 seconds).

[0042] Next, a case in which the water seal position in a flush toilet falls below a specified water seal level will be explained with reference to Figure 5. Figure 5 is a side cross-sectional view of a flush toilet showing a state in which the water seal position is lower than a specified 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 water 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 the toilet is installed or the power is turned on, 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 material clogs the water distribution pipe or drain trap pipe, causing 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 material clog is cleared. The water seal position will also be lowered if the amount of flush water supplied (refilled) to the bowl is simply small.

[0044] The inventors have discovered that when wash water is discharged from the jet water outlet 14 with the water seal position lowered below a predetermined water seal level, air accumulated in the jet water conduit 16 is ejected from the jet water outlet 14, pushing out the wash water and causing water splashing. Therefore, the present inventors conducted experiments to verify what kind of water sealing position is most likely to cause water splashing.

[0045] Fig. 6 is a graph obtained by experiment, 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 when the water sealing position (water sealing depth) is in the vicinity of the upper end of the jet water discharge port 14, the largest number of water droplets are ejected.

[0046] Next, a method for detecting that 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 the water level sensor 46 detects that 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 of water supply to the water storage tank 4. That is, when the water seal position is at a predetermined water seal level, the water level in the water storage tank 4 drops to a predetermined dead water level (DWL) after jet water discharge has been performed. However, for example, if waste is clogged in the drain pipe or drain trap pipe 8 and the water seal position is lower than 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, so the water level drops below the predetermined dead water level (DWL). When water supply to the water storage tank 4 is started from this state, the time from the dead water level (DWL) to the stop water level (WL0) detected by the float switch 28 is extended, causing a deviation from the normal water supply time. This deviation in water supply time (longer water supply time) makes it possible to detect the lowering of 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 is lower than a predetermined dead water level, thereby detecting a lowering of the seal water position.

[0048] As another example of detecting a lowering of the water seal position, a change in the inflow from the water source is predicted from the time required for the water level to rise from the dead water level (DWL) to the dead water level (WL0) in the water storage tank 4, and if it takes longer than usual for the water level to rise, in other words, if the water supply time is longer than usual, there is a possibility that the inflow from the water source is decreasing. In such a case, the water seal position will drop due to insufficient refill by the rear rim spout described below, and the lowering of the water seal position can be detected from the time it takes for the water level to rise in the water storage tank.

[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 to the bowl portion 6 before jet water spouting is performed, and jet water spouting is performed in a state in which the water seal position has returned to the predetermined water seal position. The replenishment of flush water to the bowl portion 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 of 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 due to this longer time, the amount of flush water supplied to the bowl portion 6 is made greater 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 is started 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 from its upper end into the overflow pipe 36, pass through the jet water conduit 16, and be replenished into the bowl section 6, and the water seal position returns 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 bowl section 6 up to seal water level W, and flush water has also accumulated in jet conduit 16 up to the same height as the seal water level. At this time, air is retained in a part of upstream flow path 16a located directly below 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 (seal water) remaining in bowl portion 6 and flush water from rim water spouting combine with flush water from jet water spouting, and a large flow rate of flush water flows into drain trap pipe 8, causing a strong siphon effect and discharging waste.

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

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

[0058] Next, as shown in Fig. 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 the original standby state as shown in Fig. 5(a).

[0059] Next, the instantaneous flow rate of flush water spouted from the rim spout during the large flush and small flush, 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 in a flush toilet according to an embodiment of the present invention 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 in a 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 flushing water discharged from the jet water outlet 14, the dotted line indicates the instantaneous flow rate of flushing water discharged from the rim water outlet 10, and the solid line indicates the instantaneous flow rate of flushing water flowing into the inlet 8a of the drain trap pipe 8.

[0061] As shown in Figure 8A, in a large flush, at time t2, the drain valve 38 is opened 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 is closed, which causes the instantaneous flow rate of the jet water spouting to also decrease.

[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 performed. Furthermore, flush water discharged by the rear rim discharge during the previous flush remains in the bowl portion 6 as pooled water. As a result, 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 rate 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-silhouette water storage tank (although siphon action is unlikely to occur with this jet water alone), the flush water from the rim water spout and the pooled water 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.

[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 wash water from the jet water spouting and rim water spouting decreases, but this allows the siphon action to continue. In this way, a strong siphoning action can be generated and continued without increasing the amount of water stored in the water storage tank 4, thereby achieving water conservation.

[0065] Next, as shown in Figure 8B, in the small flush, at time t2, the drain valve 38 is opened 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 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 is closed, which causes the instantaneous flow rate of 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 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 spout and rim spout flows into the inlet 8a of the drain trap pipe 8. However, after time t4, the flush water from the rim spout and the pooled water remaining in the bowl section 6 combine with the flush water from the jet spout, 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 alone), the flush water from the rim water spout and the pooled water 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 water spout and rim water spout decreases, but this allows the siphoning action to continue. In this way, even in the case of a small flush, a strong siphoning action can be generated without increasing the amount of water stored in the water tank 4, and this siphoning 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, for example, if a large amount of waste is discharged while clogging, and the siphon breaks after flush water is replenished to the water storage tank 4, the water seal position may drop. When the jet is discharged from the jet water outlet 14 with the water seal position lowered, 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 water splashing. According to the flush toilet 1 of this embodiment, when the seal position is lower than a predetermined seal water level, flush water (seal water) is replenished into the bowl portion 6 to raise the seal position, or to a level close to the predetermined seal water level, and jet water is discharged in this state, so that air accumulated in the jet water conduit 16 is ejected from the jet water discharge port 16, pushing out the flush water and preventing water splashing.

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

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

[0072] Fourthly, 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 seal 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 bowl body 4. Water tank 6 Bowl section 8 Drain trap line 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 section 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 type flush toilet, A bowl portion having a waste receiving surface and a rim portion formed along an upper edge portion of the waste receiving surface, the bowl portion having a seal water having a predetermined seal water level formed at a lower portion 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 below the bowl portion, the drain trap pipe having an ascending pipe extending upward from below 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 water outlet disposed below the bowl portion so as to discharge flush water toward an inlet of the drain trap pipe; a water storage tank for storing wash 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 a rim spouting that spouts wash water from the rim spouting port and a jet spouting that spouts wash water from the jet spouting port; 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 portion to raise the water seal position, and in this state, jet water is discharged.

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 passage.

3. 2. The flush toilet according to 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 dead water level value, the stop water level value, or the time it takes to supply water to the water storage tank until the stop water level is reached, detected by this tank water level detection means.

4. 4. The flush toilet according to claim 3, wherein the tank water level detection means is a float switch that detects the stop water level in 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 claimed in claim 1, further comprising an overflow pipe within the water storage tank for discharging flush water within the water storage tank into the jet water conduit when the time it takes to supply water to the water storage tank for the water level within 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 caused 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 replenished to the bowl portion to raise the water seal position to near a predetermined water seal level.

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