flush toilet

Abstract

To provide a siphon jet flush toilet capable of reducing pressure loss that occurs caused by air between a jet drain valve and a jet waterway flowing out of a jet spout water port.SOLUTION: A siphon jet flush toilet 1 includes: a water tank 4 that stores the washing water supplied to the jet spout water port; a jet waterway 16 that is arranged so that the washing water in the water tank is guided due to the head pressure of the washing water in the water tank to the jet spout water port; and a controller that controls rim spout water spouted from and a jet spout water spouted from the jet spout water port. A jet drain valve is equipped with a valve body, and the valve body is located below the top surface of the bowl and above the seal water level and arranged to reduce air A present between the valve body of the jet drain valve and the water surface of the jet waterway by supplying the washing water to the jet waterway before opening the jet drain valve.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] In the flush toilet of Patent Document 1 mentioned above, the tank is positioned to have a low silhouette, and furthermore, the jet water is directed into the jet water conduit by the head pressure of the flush water in the tank, so there is a space between the valve body of the drain valve and the water level (= seal water level) of the jet water conduit, and when the tank's drain valve is opened to supply flush water into the jet water conduit, air in that space flows out from the jet water outlet, causing a pressure loss. Furthermore, in the flush toilet of Patent Document 2, as in the flush toilet of Patent Document 1, pressure loss occurs due to air flowing out from the jet spout.

[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 reduce the pressure loss caused by air present between the jet drain valve and the jet water conduit flowing out of the jet spout. [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 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, a top portion located between the ascending pipe and the descending pipe and defining 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 jet drain valve, The device comprises a water storage tank that stores flush water to be supplied to the jet spout, a jet water conduit that connects the water storage tank to the jet spout and allows the flush water in the water storage tank to be directed to the jet spout by the head pressure of the flush water in the water storage tank, and a control device that controls the rim water spout that is spouted from the rim spout and the jet water spout that is spouted from the jet spout, the jet drain valve having a valve body that is positioned lower than the top surface of the bowl part and higher than the seal water level, and before the jet drain valve is opened, flush water is supplied to the jet water conduit to reduce any air that exists between the valve body of the jet drain valve and the water surface in the jet water conduit. According to the present invention configured in this manner, flushing water is supplied to the jet water conduit before the jet drain valve is opened to reduce the air present between the jet drain valve and the upper part of the jet water conduit, so that when flushing water is supplied from the water storage tank to the jet water conduit, the pressure loss caused by this air flowing out from the jet water outlet can be reduced.

[0007] In the present invention, preferably, flush water is supplied to the jet water conduit, the water level in the jet water conduit rises to the vicinity of the jet drain valve, and the air is discharged, and then the jet drain valve is opened. According to the present invention configured in this manner, the jet drain valve is opened after the water level in the jet water conduit rises to the vicinity of the jet drain valve and the air is discharged, thereby reducing pressure loss due to air when wash water is discharged from the jet water outlet.

[0008] In the present invention, it is preferable that the device further includes an exhaust pipe extending from below the valve body of the jet drain valve to above the stop water level in the water storage tank. With this invention configured as described above, the exhaust pipe effectively exhausts any air remaining between the jet drain valve and the water surface of the jet water conduit. Furthermore, because the air is exhausted from the exhaust pipe into the water storage tank, the amount of air that flows out as air bubbles onto the water sealing surface (reservoir surface) of the bowl surface can be reduced, so cleaning is not adversely affected by these air bubbles.

[0009] In the present invention, the exhaust pipe is preferably provided inside the water storage tank. According to the present invention configured as described above, the exhaust pipe is provided inside the water storage tank, which makes it easy to install the exhaust pipe. The exhaust pipe also functions as an overflow pipe.

[0010] In the present invention, preferably, before the jet drain valve of the water storage tank is opened, flush water is discharged from the rim outlet to raise the water level in the bowl section, thereby supplying flush water to the jet water conduit. According to the present invention configured in this way, flush water is discharged from the rim spout to raise the water level in the bowl section before the jet drain valve of the water storage tank is opened, thereby supplying flush water to the jet water conduit. Therefore, the bowl section is cleaned with flush water discharged from the rim spout, and the flush water after cleaning raises the water level in the bowl section, allowing flush water to be supplied to the jet water conduit. Furthermore, water can be saved because flush water from the bowl section can be used. Furthermore, because flush water is supplied from the bowl section to the jet water conduit, air can easily escape through the exhaust pipe. As a result, fewer bubbles are discharged into the bowl section, making them less noticeable to the user.

[0011] In the present invention, preferably, before the jet drain valve of the water storage tank is opened, a portion of the flush water supplied to the water storage tank is guided from the water storage tank to the jet water conduit by the exhaust pipe. According to the present invention configured in this manner, flush water is guided into the jet water conduit, which raises the water level in the jet water conduit and also raises the water level in the water storage tank.

[0012] In the present invention, the exhaust pipe is preferably arranged rearward of the jet drain valve in the front-rear direction. According to the present invention configured in this manner, the exhaust pipe is positioned rearward of the drain valve, so when the jet drain valve of the water tank is opened, the cleaning water flows out of the water tank toward the front, and the air is guided rearward and reliably discharged from the exhaust pipe. [Effects of the Invention]

[0013] The siphon jet flush toilet of the present invention can reduce pressure loss caused by air existing between the jet drain valve and the jet water conduit flowing out from the jet spout. [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. 10 is a side cross-sectional view of a flush toilet according to an embodiment of the present invention, illustrating the presence of air between the jet drain valve and the jet water conduit. [Figure 6] 10 is a time chart showing another example of removing air present between the jet drain valve and the jet water conduit. [Figure 7] FIG. 10 is a partial plan view showing another example of the arrangement of the jet drain valve and overflow pipe (exhaust pipe) of a flush toilet according to an embodiment of the present invention. [Figure 8] FIG. 2 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention. [Figure 9A] 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 9B] 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) attached to the floor or wall 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 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.

[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 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.

[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 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 tank made of resin. The bottom 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.

[0025] 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 water stop level (WLO). 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 operation signals from the user, and an operation unit (not shown) that sends out operation signals in response to user 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 comprises an overflow pipe 36 that drains overflowing water from the water storage tank 4 into the toilet body, a jet drain valve 38 fixed to the lower end of the overflow pipe 36, and a toilet flushing unit 40 that opens and closes the jet 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 jet 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.

[0028] 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.

[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 jet 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 presence of air between the jet drain valve and the jet waterway in a flush toilet 1 according to this embodiment will be explained using Figure 5. Figure 5 is a side cross-sectional view of a flush toilet to explain the presence of air between the jet drain valve and the jet waterway in a flush toilet according to an embodiment of the present invention.

[0044] As shown in Figure 5, in a flush toilet 1 in standby mode, the flush water discharged by the rear rim discharge described above is stored as seal water (reserved water) in the lower part of the bowl portion 6. As a result, the jet water conduit 16 is filled with flush water up to a height position corresponding to the seal water level. Meanwhile, because the valve element 38a of the jet drain valve 38 is positioned above the seal water level, air A remains between the valve element 38a of this jet drain valve 38 and the upper part of the jet water conduit 14. During jet water discharge, when the jet drain valve 38 is opened and flush water in the water storage tank 4 flows out into the jet water conduit 16 and is discharged from the jet water spout 14, this air A becomes mixed into the jet water discharge, causing a popping sound and also resulting in pressure loss.

[0045] In this embodiment, in order to reduce the pressure loss caused by this air A, the air A remaining between the valve body 38a of the jet drain valve 38 and the upper part of the jet water conduit 14 is discharged to the outside before the jet drain valve 38 opens, as in the first and second examples described below.

[0046] First, the first example will be explained with reference to Figure 3. As shown in Figure 3, after the standby state, at time t1, the rim-side solenoid valve 30 opens and flush water is spouted from the rim spout port 10 (i.e., the pre-rim spouting described above is performed), and this flush water is supplied to the bowl section 6, causing the seal water surface (reserved water surface) W to rise from the seal water level, and the water level in the bowl section 6 to be higher than the seal water level. At this time, flush water in the bowl section 6 is supplied from the jet spout port 14 into the jet water conduit 16, causing the water level in the jet water conduit 16 to rise to the vicinity of the valve body 38a of the jet drain valve 38. In this way, it is preferable that the amount of flush water spouted from the rim spout port 10 is an amount that can raise the water level in the jet water conduit 16 to the vicinity of the valve body 38a of the jet drain valve 38. At this time, the overflow pipe 36 is positioned so as to extend from below the valve body 38a of the jet drain valve 38 to above the stop water level, so that when the water level in the jet water conduit 16 rises, air A passes through the inside of the overflow pipe 36 and is discharged into the space above the water storage tank 4. At this time, the overflow pipe 36 functions as an exhaust pipe.

[0047] In this first example, after flush water is discharged from the rim spout 10 at time t1, the jet drain valve 38 is opened at time t2, so that the flush water flowing into the jet water conduit 16 does not contain air, and even if it does contain air, the amount is quite small, so that pressure loss can be reduced when flush water is discharged from the jet spout 14.

[0048] In the first example described above, the rim-side solenoid valve 30 opens and flush water is discharged from the rim water discharge port 10, thereby raising the water sealing surface W from the water sealing position. Instead of this first example, the following modified example may be used. That is, a rim drain valve (not shown) may be provided in the water storage tank 4 together with the jet drain valve 38, and this rim drain valve may be opened to raise the position of the water sealing surface W.

[0049] Next, a second example will be described with reference to Fig. 6. Fig. 6 is a time chart showing another example (second example) for removing air existing between the jet drain valve and the jet water conduit. As shown in Figure 6, after the standby state, between time t11 and time t12, the tank solenoid valve 34 is opened and flush water is supplied to the water storage tank 4. At this time, the water level in the water storage tank 4 is at the stop water level, so when this water supply causes the water level in the water storage tank 4 to rise from the stop water level to the upper end of the overflow pipe 36, flush water flows into the overflow pipe 36 from the upper end opening of the overflow pipe 36 and is supplied to the jet water conduit 16. As a result, the water level in the jet water conduit 16 rises to the vicinity of the valve body 38a of the jet drain valve 38. As a result, air A passes through the inside of the overflow pipe (exhaust pipe) 36 and is discharged into the space above the water storage tank 4.

[0050] In this second example, the jet drain valve 38 is opened at time t2, after time t12 when the supply of flush water into the water storage tank 4 has finished, so the flush water that flows out into the jet water conduit 16 does not contain air, and even if it does contain air, it is in a very small amount, so that pressure loss can be reduced when the flush water is discharged from the jet water outlet 14.

[0051] Next, another example of the arrangement of the jet drain valve and overflow pipe will be explained with reference to Figure 7. Figure 7 is a partial plan view showing another example of the arrangement of the jet drain valve and overflow pipe (exhaust pipe) of a flush toilet according to an embodiment of the present invention. 7, in this example, the jet drain valve 50 does not have an overflow pipe, and only lightly closes the drain outlet of the water storage tank 4. Furthermore, the overflow pipe 52 is arranged rearward of the jet drain valve 50.

[0052] Next, the flushing operation of a flush toilet according to an embodiment of the present invention will be explained with reference to Figure 8. Figure 8 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention.

[0053] 8(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, as described above, air A is retained between the valve body 38a of the jet drain valve 38 in the water storage tank 4 and the upper part of the jet water conduit 16.

[0054] Next, as shown in Figure 8(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 stagnant air A is expelled from the overflow pipe 36, filling the jet water conduit 16 with water (see the first example above).

[0055] After this, as shown in Figure 8(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 8(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 8(e), the flush water level in the bowl section 6 drops as the accumulated water is discharged by 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, 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 has also accumulated in the jet water conduit 16 up to the same height as the seal water level.

[0058] Next, as shown in Figure 8(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 8(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 9A and 9B. 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.

[0060] In Figures 9A and 9B, 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 9A, 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 jet 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 9B, in a small flush, at time t2 the jet 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 jet drain valve 38 closes, which causes the instantaneous flow rate of the jet water spouting to decrease as well.

[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, with the flush toilet 1 of this embodiment, flush water is supplied to the jet water conduit 16 before the jet drain valve 38 is opened, reducing the amount of air A present between the jet drain valve 38 and the upper part of the jet water conduit 16, so when flush water is supplied from the water storage tank 4 to the jet water conduit 16, the pressure loss caused by this air flowing out from the jet water outlet 14 can be reduced.

[0070] (Claim 2) Secondly, with the flush toilet 1 of this embodiment, the jet drain valve 38 is opened after the water level in the jet water conduit 16 has risen to the vicinity of the jet drain valve 38 and air A has been discharged, so that when flush water is discharged from the jet water outlet 14, pressure loss due to air can be reduced.

[0071] Thirdly, with the flush toilet 1 of this embodiment, the overflow pipe (exhaust pipe) 36 can effectively exhaust air A remaining between the jet drain valve 38 and the water surface of the jet water conduit 16. Furthermore, because air A is exhausted from the overflow pipe 36 into the water storage tank 4, less air flows out as bubbles onto the water sealing surface (reservoir surface) W of the bowl surface 6, so cleaning by these bubbles is not adversely affected.

[0072] Fourth, with the flush toilet 1 of this embodiment, the overflow pipe is provided inside the storage tank 4, making it easy to install the overflow pipe .

[0073] Fifth, with the flush toilet 1 of this embodiment, flush water is discharged from the rim spout 10 before the jet drain valve 38 of the water tank 4 is opened, raising the water level in the bowl section 6, and as a result, flush water is supplied to the jet water conduit 12, so that the bowl section 6 is flushed with flush water discharged from the rim spout 10, and the rise in the water level in the bowl section 6 due to the flush water after this flush is used to supply flush water to the jet water conduit 16. Furthermore, water is saved because the flush water in the bowl section 6 can be used. Also, because flush water is supplied from the bowl section 6 to the jet water conduit 16, air A is more easily released from the overflow pipe 36, and as a result, fewer air bubbles are discharged into the bowl section 6, making them less noticeable to the user.

[0074] Sixth, with the flush toilet 1 according to this embodiment, flush water is guided to the jet water conduit 16, causing the water level in the jet water conduit 16 to rise, and the water level in the water tank 4 can also be raised.

[0075] Seventh, with the flush toilet 1 of this embodiment, the overflow pipe 52 is positioned rearward of the jet drain valve 50, so when the jet drain valve 38 of the water storage tank 4 is opened, flush water flows out from the water storage tank 4 toward the front, and air A is guided rearward and reliably discharged from the overflow pipe 38. [Explanation of symbols]

[0076] 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, 52 Overflow pipe (exhaust pipe) 38, 50 Jet 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 jet 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 that guides flush water in the water storage tank to the jet water outlet by the head pressure of the flush water in 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 jet drain valve includes a valve body, and the valve body is positioned lower than the upper surface of the bowl portion and higher than the seal water level, In this flush toilet, flush water is supplied to the jet waterway before the jet drain valve is opened, thereby reducing the amount of air present between the valve body of the jet drain valve and the water surface in the jet waterway.

2. 2. A flush toilet according to claim 1, wherein flush water is supplied to the jet water conduit, the water level in the jet water conduit rises to the vicinity of the jet drain valve, and the air is discharged, after which the jet drain valve is opened.

3. 3. The flush toilet according to claim 1 or 2, further comprising an exhaust pipe extending from below the valve body of the jet drain valve to above the stop water level in the water storage tank.

4. The flush toilet according to claim 3, wherein the exhaust pipe is provided inside the water storage tank.

5. A flush toilet as set forth in claim 3, wherein flush water is discharged from the rim spout to raise the water level in the bowl section before the jet drain valve of the water storage tank is opened, thereby supplying flush water to the jet water conduit.

6. A flush toilet as set forth in claim 4, wherein a portion of the flush water supplied to the water storage tank is guided from within the water storage tank to the jet water conduit by the exhaust pipe before the jet drain valve of the water storage tank is opened.

7. The flush toilet according to claim 3, wherein the exhaust pipe is positioned rearward of the jet drain valve in the front-to-rear direction.

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