Water-washable toilet

Abstract

To provide a siphon jet flush toilet capable of ensuring waste discharge performance by creating sufficient siphoning force even when a water tank is placed in a low silhouette.SOLUTION: A siphon jet flush toilet includes: a rim spout water port for spouting washing water to a bowl; a drain trap pipe; and a jet spout water port for spouting the washing water toward the entrance of the drain trap pipe; and a drain valve 38. The flush toilet further includes: a water tank for storing the washing water supplied to the jet spout water port; a jet waterway that guides the washing water via the head of the water tank to a jet spout water port from the water tank; and a controller that controls rim spout water and jet spout water. The valve body of the drain valve is placed at a position lower than the top of the bowl and higher than the seal water level. The controller is configured to control to spout washing water continuously from the rim spout water port in the order of "pre-rim water spout", "middle rim water spout", and "post rim water spout" in this order, and to perform "jet spout water" from the jet spout water port while performing "middle rim water spout".SELECTED DRAWING: Figure 3

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] In the flush toilet of Patent Document 1 mentioned above, the water storage tank is positioned to have a low silhouette, and furthermore, the jet water is directed to the jet water conduit by the head pressure of the flush water in the tank, so the flow rate of the flush water discharged from the jet spout is slower than in flush water that is directed to the jet water conduit by a pump, and therefore the force of attraction to the drain trap pipe due to siphon action is smaller.In the flush toilet of Patent Document 2 mentioned above, the water storage tank that directs flush water to the jet spout is located above the bowl, so the issue of reduced attraction force due to siphon action that occurs in the flush toilet of Patent Document 1 does not exist.

[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 can generate sufficient pulling force through the siphon action to ensure waste discharge performance, even when the water storage tank is positioned in a low silhouette and the jet water is directed into the jet water conduit by the head pressure of the flush water in the water storage tank. [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; a rim spout formed in the rim portion that spouts 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 that is located between the ascending pipe and the descending pipe and determines the seal water level; a jet spout positioned below the bowl portion so as to spout flush water toward the inlet of the drain trap pipe; and a drain valve, The device comprises a water storage tank for storing flush water to be supplied to the water spout, a jet water conduit that connects the water storage tank to the jet spout and directs flush water from the water storage tank to the jet spout using the head of the water storage tank, rim spout that is spouted from the rim spout, and a control device that controls the jet spout that is spouted from the jet spout, the drain valve having a valve body that is positioned lower than the top surface of the bowl part and higher than the sealed water level, and the control device controls the flush water to be spouted from the rim spout in succession in order as "front rim spout," "middle rim spout," and "rear rim spout" and to perform "jet spout" from the jet spout when "middle rim spout" is being performed. In the present invention configured as described above, the washing water is continuously discharged in sequence as "front rim water discharge", "middle rim water discharge", and "rear rim water discharge" from the rim water discharge port, and the sequence control is such that "jet water discharge" is performed from the jet water discharge port when "middle rim water discharge" is being carried out. As a result, the washing water supplied to the bowl portion by the front rim water discharge and the accumulated water remaining in the bowl portion due to the rear rim water discharge during the previous washing are combined with the washing water by the jet water discharge, and a large flow rate of washing water flows into the drain trap pipe to generate a siphon. In addition, the siphon action can be continued by the washing water by the subsequent jet water discharge and the washing water by the middle rim water discharge. As a result, according to the present invention, even when the washing water is supplied to the jet water conduit by the head pressure of the washing water in the water storage tank with a low siphon, the dirt can be surely discharged by the strong siphon action, and furthermore, water conservation can be achieved.

[0007] In the present invention, preferably, the water discharge time of the front rim water discharge is shorter than the water discharge time of the rear rim water discharge. According to the present invention configured as described above, the bowl portion can be washed by the front rim water discharge with a washing water amount less than the washing water by the rear rim water discharge, and furthermore, the siphon action can be generated by the washing water.

[0008] In the present invention, preferably, the total water discharge time of the front rim water discharge and the middle rim water discharge is shorter than the water discharge time of the rear rim water discharge. According to the present invention configured as described above, the front rim water discharge and the middle rim water discharge with a washing water amount less than the washing water by the rear rim water discharge can generate a siphon action together with the jet water discharge and continue the siphon.

[0009] In the present invention, preferably, the water stop level of the washing water in the water storage tank is set higher than the upper surface of the bowl surface. According to the present invention configured as described above, since the water stop level (WL0) of the washing water in the water storage tank is set higher than the upper surface of the bowl surface, a large head pressure can be obtained.

[0010] In the present invention, the flush water stop level in the water storage tank is preferably set lower than the upper surface of the bowl surface. According to the present invention configured in this manner, the flush water stopping water level (WL0) in the water storage tank is set lower than the upper surface of the bowl surface, so the height of the water storage tank can be lowered, making it possible to achieve a lower silhouette.

[0011] In the present invention, the control device preferably supplies water to the water tank after the rear rim water spouting has ended. According to the present invention configured in this manner, water is supplied to the water tank after the rear rim water discharge has ended, so that the rim water discharge can be continued at a constant flow rate and the flow rate does not decrease. [Effects of the Invention]

[0012] With the siphon jet flush toilet of the present invention, even if the water storage tank is positioned to have a low silhouette and the jet water is guided into the jet water conduit by the head pressure of the flush water in the tank, sufficient pulling force is generated by the siphon action, ensuring waste discharge performance. [Brief explanation of the drawings]

[0013] [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. 2 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention. [Figure 6A] 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 6B] 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

[0014] 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.

[0015] 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).

[0016] 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.

[0017] 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.

[0018] 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) attached to the floor or wall via a drain socket (not shown).

[0019] 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 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, cleaning it.

[0020] 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.

[0021] Jet water spout 14 is formed in the bottom of bowl portion 6. Jet water spout 14 is positioned opposite inlet 8a of drain trap pipe 8 and is directed toward inlet 8a of drain trap pipe 8. Jet water spout 14 spouts flush water toward inlet 8a of drain trap pipe 8, and this flush water flows into drain trap pipe 8, activating the siphon action.

[0022] 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.

[0023] 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 the stop water level (WL0), and flush water from the stop water level to the 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 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 water storage tank 4 may also be a ceramic tank that is integrated with the toilet body 2.

[0024] Provided within the water storage tank 4 are 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). Also provided outside the water storage tank 4 are a controller 29 that controls the water supply device 24 and drainage device 26 to operate or stop based on an operation signal from the user, and an operation unit (not shown) that sends out an operation signal in response to operation by the user.

[0025] The water supply device 24 comprises a constant flow valve (not shown) connected to the water supply, a rim-side solenoid valve 30 which supplies or stops the flow of flush water to the rim spout 10, and a tank-side solenoid valve 34 which 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 tank-side solenoid valve 34 are controlled by commands from a controller 29 based on operation signals from the user and water level detection signals from a float switch 28.

[0026] The drainage device 26 comprises 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 so that overflowing water from the water storage tank 4 is discharged 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 operation signals from the user.

[0027] As mentioned above, the flush toilet 1 is a low-silhouette type toilet, but more specifically, as shown in Figure 2, the valve body 38a of the jet drain valve 38 is positioned lower than the upper surface of the bowl portion 6 (upper surface of the rim portion 20) and higher than the seal water level.

[0028] 2, the water level (WL0) of the water storage tank 4 is set higher than the upper surface of the rim portion 20 of the bowl portion 6. As a variant, the water level may be set lower than the upper surface of the rim portion 20 of the bowl portion 6.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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).

[0040] 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).

[0041] 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).

[0042] 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).

[0043] Next, the flushing operation of a flush toilet according to an embodiment of the present invention will be explained with reference to Figure 5. Figure 5 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention.

[0044] 5(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 A is stagnating in a part of the upstream flow path 16a located directly below the water storage tank 4.

[0045] Next, as shown in Figure 5(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 the trapped air A is expelled from the overflow pipe 36, filling the jet water conduit 16 with water.

[0046] After this, as shown in Figure 5(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 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.

[0047] Next, as shown in Figure 5(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.

[0048] Thereafter, as shown in Figure 5(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.

[0049] Next, as shown in Figure 5(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).

[0050] 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 6A and 6B. Figure 6A 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 6B 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.

[0051] In Figures 6A and 6B, 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.

[0052] As shown in Figure 6A, 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Next, as shown in Figure 6B, 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 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 jet water spouting to decrease as well.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Next, the effects achieved by the flush toilet according to the embodiment of the present invention described above will be explained. First, in the flush toilet 1 according to this embodiment, flush water is successively discharged from the rim spout 10 in the order "front rim spouting," "middle rim spouting," and "rear rim spouting," and the sequence is controlled so that "jet spouting" is performed from the jet spout 14 when "middle rim spouting" is being performed, so that the flush water supplied to the bowl section 6 by the front rim spouting and the pooled water remaining in the bowl section 6 by the rear rim spouting from the previous flush combine with the flush water from the jet spouting, causing a large flow rate of flush water to flow into the drain trap pipe 8, generating a siphon, and the siphoning action can be continued by the subsequent flush water from the jet spouting and the flush water from the middle rim spouting. As a result, according to this embodiment, even if flush water is supplied to the jet water conduit 16 by the head pressure of the flush water from the storage tank 4, which has a low silhouette and limited volume, a powerful siphoning action can be used to reliably discharge waste, and water conservation can also be achieved.

[0061] Secondly, with the flush toilet 1 according to this embodiment, the spouting time of the front rim spout is shorter than the spouting time of the rear rim spout, so the bowl section 6 is flushed with a smaller amount of flush water than the flush water produced by the rear rim spout, and furthermore, a siphon effect can be generated by this flush water.

[0062] Thirdly, with the flush toilet 1 of this embodiment, the total spouting time of the front rim spout and the middle rim spout is shorter than the spouting time of the rear rim spout, so the front rim spout and the middle rim spout, which have a smaller amount of flush water than the flush water from the rear rim spout, can generate a siphoning action along with the jet spout, allowing the siphoning to continue.

[0063] Fourth, with the flush toilet 1 of this embodiment, the flush water stop level (WL0) in the reservoir tank 4 is set higher than the upper surface of the bowl surface 6, allowing for a large head pressure.

[0064] Fifth, with the flush toilet 1 of this embodiment, the flush water stop level (WL0) in the water tank is set lower than the upper surface of the bowl surface, so the height of the water tank 4 can be lowered, making it possible to achieve an even lower silhouette.

[0065] Sixth, with the flush toilet 1 of this embodiment, the controller 29 supplies water to the water storage tank 4 after rear rim spouting has finished, so rim spouting can continue at a constant flow rate and the flow rate does not decrease. [Explanation of symbols]

[0066] 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 W Water sealing surface (water storage surface) WL0 Water stop level DWL dead water level A. Air

Claims

1. A siphon jet flush toilet, a bowl portion having a waste receiving surface and a rim portion formed along an upper edge of the waste receiving surface; 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 located between the ascending pipe and the descending pipe and defining a 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 equipped with a drain valve and configured to store 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 flush water from the water storage tank to the jet water outlet through the head of the water storage tank; A control device that controls rim spouting that is discharged from the rim spouting port and jet spouting that is discharged from the jet spouting port, The drain valve has a valve body, and the valve body is arranged at a position lower than the rim spout and higher than the seal water level, The control device controls the flush toilet so that flush water is successively discharged from the rim spout in the order of "front rim spouting," "middle rim spouting," and "rear rim spouting," and also controls so that "jet spouting" is performed from the jet spout when "middle rim spouting" is being performed.

2. The flush toilet according to claim 1, wherein the spouting time of the front rim spouting is shorter than the spouting time of the rear rim spouting.

3. The flush toilet according to claim 1, wherein the total spouting time of the front rim spouting and the middle rim spouting is shorter than the spouting time of the rear rim spouting.

4. 2. The flush toilet according to claim 1, wherein the flush water stop level in the water storage tank is set higher than the upper surface of the bowl surface.

5. 2. The flush toilet according to claim 1, wherein the flush water stop level in the water storage tank is set lower than the upper surface of the bowl surface.

6. 2. The flush toilet according to claim 1, wherein the control device supplies water to the water tank after rear rim spouting has finished.

7. A siphon jet flush toilet, a bowl portion having a waste receiving surface and a rim portion formed along an upper edge of the waste receiving surface; 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 located between the ascending pipe and the descending pipe and defining a 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 equipped with a drain valve and configured to store 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 flush water from the water storage tank to the jet water outlet through the head of the water storage tank; A control device that controls rim spouting that is discharged from the rim spouting port and jet spouting that is discharged from the jet spouting port, The drain valve includes a valve body, and the valve body is disposed at a position lower than the upper surface of the bowl portion and higher than the seal water level. The control device controls flush water to be discharged from the rim spout in succession in the order of "front rim spouting," "middle rim spouting," and "rear rim spouting," and also controls so that "jet spouting" is performed from the jet spout when "middle rim spouting" is being performed, A flush toilet in which the water discharge time of the front rim water discharge is shorter than the water discharge time of the rear rim water discharge.

8. A siphon jet flush toilet, a bowl portion having a waste receiving surface and a rim portion formed along an upper edge of the waste receiving surface; 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 located between the ascending pipe and the descending pipe and defining a 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 equipped with a drain valve and configured to store 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 flush water from the water storage tank to the jet water outlet through the head of the water storage tank; A control device that controls rim spouting that is discharged from the rim spouting port and jet spouting that is discharged from the jet spouting port, The drain valve includes a valve body, and the valve body is disposed at a position lower than the upper surface of the bowl portion and higher than the seal water level. The control device controls flush water to be discharged from the rim spout in succession in the order of "front rim spouting," "middle rim spouting," and "rear rim spouting," and also controls so that "jet spouting" is performed from the jet spout when "middle rim spouting" is being performed, A flush toilet in which the total water discharge time of the front rim water discharge and the middle rim water discharge is shorter than the water discharge time of the rear rim water discharge.

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