JP7751794B2 - flush toilet - Google Patents

Description

The present invention relates to flush toilets, and in particular to siphon jet flush toilets.

Siphon jet flush toilets have been known in the past, 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, for example. Also known is a siphon jet flush toilet that continuously spouts front, middle, and rear rim water, and also spouts jet water when spouting middle rim water (sequential control), as described in Patent Document 2.

Patent No. 5180295 JP 2023-32964 A

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 of 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.

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.

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.

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.

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.

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.

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.

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.

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.

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 of the jet spout.

1 is a plan view showing a flush toilet according to an embodiment of the present invention. FIG. FIG. 2 is a side cross-sectional view taken along line II-II in FIG. 1. 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. 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. 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. 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. 10 is a time chart showing another example of removing air present between the jet drain valve and the jet water conduit. 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. FIG. 2 is a diagram for explaining the flushing operation of a flush toilet according to an embodiment of the present invention. 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. 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.

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.

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 rear upper part of the toilet body 2 and covered by a resin cover (not shown).

The toilet body 2 is formed with a bowl portion 6 for receiving waste, a drain trap pipe 8 located 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 directing flushing water to the rim spout 10, a jet spout 14 for jet water discharge, and a jet water conduit 16 for directing flushing water to the jet spout 14.

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 line 16. A water sealing surface (reservoir surface) W is formed inside this pot portion 22.

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).

The rim spout 10 is formed on the rear left side of the rim portion 20 when viewing the toilet body 2 from the front. The rim spout 10 spouts flush water forward, and this flush water swirls around the inner 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.

The rim conduit 12 is formed in a tapered shape, with the flow path cross section gradually decreasing towards the rim spout 10. A water supply hose 23 that connects directly 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 the flush water is discharged from the rim spout 10 due to the water supply pressure of the water supply.

The jet water outlet 14 is formed at the bottom of the bowl portion 6. The jet water outlet 14 is positioned 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 action.

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 is discharged from the jet water outlet 14 due to the head pressure of the flush water.

The water storage tank 4 is a gravity-fed tank that stores flush water 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 bottom of the water storage tank 4 is located below the top surface of the rim portion 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 is provided with 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 reaches the water stop level (WLO). Also provided outside the water storage tank 4 is 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 transmits operation signals in response to user operation.

The water supply device 24 is equipped with a constant flow valve (not shown) connected to the water supply, a rim-side solenoid valve 30 that supplies or stops flush water to the rim spout 10, and a tank-side solenoid valve 34 that supplies or stops flush water to the 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 driven by commands from the controller 29 based on operation signals from the user and water level detection signals from the float switch 28.

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 electrical drive force. The overflow pipe 36 has open upper and lower ends, allowing overflowing water from the water storage tank 4 to be 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.

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

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.

Next, we will explain the "rim water discharge," "tank water supply," "jet water discharge," and "tank water level" in the flush toilet 1 according to this embodiment using Figure 3. Figure 3 is a time chart showing the "rim water discharge," "tank water supply," "jet water discharge," and "tank water level" in the flush toilet 1 according to this embodiment of the present invention.

Here, "rim spouting" refers to the spouting of flush water from the rim spout 10, "tank water supply" refers to the supply of water to the water storage tank 4, "jet spouting" refers to the spouting of flush water from the jet spout 14, and "tank water level" refers to the level of flush water in the water storage tank 4.

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 control unit, the rim-side solenoid valve 38 turns ON at time t1, and rim spouting begins, supplying water to the rim water conduit 12 and spouting flush water from the rim spout 10. This rim spouting continues until time t5.

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 spout port 14. This jet spouting ends at time t4. While jet spouting is taking place from time t2 to time t4, rim spouting is also taking place at the same time.

Here, as is clear from Figure 3, for convenience, rim water 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," 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 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.

Next, as shown in Figure 3, the 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 the float switch 28 turns OFF. This OFF state of the float switch 28 continues until time t7.

Also, at time t6, the tank-side solenoid valve 34 opens and turns ON, starting tank water supply to the water storage tank 4, which ends 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 the float switch 28 to return to ON at time t7 when the flush water level in the water storage tank 4 rises to the stop water level, entering a full water state.

Figure 3 explains the case of a large flush, but the time chart in Figure 3 also applies to small flushes. Note that, as will be explained later, the water discharge duration and volume differ between large and small flushes.

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

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

As is clear from Figure 4A, in the case of a 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).

Similarly, as shown in Figure 4B, for small flushes, the front rim water discharge time is 1.4 seconds (s) and the water discharge volume is 0.31 liters (L), the middle rim water discharge time is 1.7 seconds (s) and the water discharge volume is 0.37 liters (L), and the rear rim water discharge time is 7.6 seconds (s) and the water discharge volume is 1.64 liters (L). Furthermore, the jet water discharge time is 1.7 seconds (s) and the water discharge volume is 1.50 liters (L).

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).

Next, using Figure 5, we will explain that air exists between the jet drain valve and the jet waterway in a flush toilet 1 according to this embodiment. Figure 5 is a side cross-sectional view of a flush toilet to explain that air exists between the jet drain valve and the jet waterway in a flush toilet according to an embodiment of the present invention.

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 corresponding to the seal water level. Meanwhile, because the valve body 38a of the jet drain valve 38 is positioned above the seal water level, air A remains between the valve body 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 into the jet water conduit 16 and is discharged from the jet water discharge port 14, this air A mixes with the jet water, generating a popping sound and also causing pressure loss.

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.

First, the first example will be described with reference to Figure 3. As shown in Figure 3, after a standby state, at time t1, the rim-side solenoid valve 30 opens, and flush water is discharged from the rim spout 10 (i.e., the pre-rim spouting described above is performed). This flush water is supplied to the bowl 6, causing the seal water surface (reservoir surface) W to rise above the seal water level, and the water level in the bowl 6 to be higher than the seal water level. At this time, flush water in the bowl 6 is supplied from the jet spout 14 into the jet conduit 16, causing the water level in the jet conduit 16 to rise to the vicinity of the valve body 38a of the jet drain valve 38. In this way, the amount of flush water discharged from the rim spout 10 is preferably an amount sufficient to raise the water level in the jet 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 that it extends from below the valve body 38a of the jet drain valve 38 to above the stop water level, so that as 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.

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 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 pressure loss can be reduced when flush water is discharged from the jet spout 14.

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

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 storage tank 4. At this time, the water level in the storage tank 4 is at the stop water level, so when this water supply causes the water level in the 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 storage tank 4.

In this second example, the jet drain valve 38 opens at time t2, after time t12 when the supply of flush water into the water storage tank 4 has finished. Therefore, 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, thereby reducing pressure loss when the flush water is discharged from the jet water outlet 14.

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 disposed rearward of the jet drain valve 50.

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

Figure 8(a) shows the standby state, with flush water pooled in the bowl section 6 up to the seal water level W, and flush water pooled 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 trapped 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.

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. Accordingly, the flush water level also gradually rises in the jet water conduit 16, and trapped air A is expelled from the overflow pipe 36, filling the jet water conduit 16 with water (see the first example above).

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

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

After that, 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 also accumulates in the jet water conduit 16 up to the same height as the seal water level.

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 the system returns to its original standby state as shown in Figure 8(a).

Next, Figures 9A and 9B will be used to explain the instantaneous flow rate of flush water discharged from the rim spout during the large flush and small flush operations in 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 6A is a diagram showing the instantaneous flow rate of flush water discharged from the rim spout during the large flush operation in 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, while Figure 6B is a diagram showing the instantaneous flow rate of flush water discharged from the rim spout during the small flush operation in 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.

In Figures 9A and 9B, the dashed line indicates the instantaneous flow rate of flush water discharged from the jet water discharge port 14, the dashed-dotted line indicates the instantaneous flow rate of flush water discharged from the rim water discharge port 10, and the solid line indicates the instantaneous flow rate of flush water flowing into the inlet 8a of the drain trap pipe 8.

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 outlet 14. The instantaneous flow rate of the jet water discharge, shown by the dashed line, increases suddenly immediately after the start and then remains approximately constant. At time t4, the drain valve 48 closes, causing the instantaneous flow rate of the jet water discharge to decrease.

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.

As a result, in this embodiment, even if flush water is supplied to the jet water conduit 16 using the head pressure of flush water from the low-profile water storage tank (although siphoning 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, resulting in a powerful siphoning effect that ensures that waste is discharged.

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 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 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.

Next, as shown in Figure 9B, during the 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 discharged from the jet water outlet 14. The instantaneous flow rate of the jet water discharge, shown by the dashed line, increases suddenly immediately after the start and then remains approximately constant. At time t4, the jet drain valve 38 closes, causing the instantaneous flow rate of the jet water discharge to decrease.

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.

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 using the head pressure of the flush water from the low-profile water storage tank (although siphon action is unlikely to occur with this jet water discharge alone), the flush water from the rim discharge and the accumulated water also flow into the inlet 8a of the drain trap pipe 8, so a powerful siphon action ensures that waste is reliably discharged.

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 small flushes, a strong siphon action can be generated without increasing the amount of water stored in the water storage tank 4, and further, this siphon action can be continued, so that water conservation can be achieved.

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 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.

(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 the 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.

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 escapes as bubbles onto the water sealing surface (reservoir surface) W of the bowl surface 6, so cleaning is not adversely affected by these bubbles.

Fourth, with the flush toilet 1 according to this embodiment, the overflow pipe 36 is provided inside the storage tank 4, making it easy to install the overflow pipe 36.

Fifth, with the flush toilet 1 of this embodiment, flush water is discharged from the rim spout 10 to raise the water level in the bowl section 6 before the jet drain valve 38 of the water storage tank 4 is opened, thereby supplying flush water to the jet water conduit 12. Therefore, 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 can be saved because flush water in the bowl section 6 can be used. Furthermore, because flush water is supplied from the bowl section 6 to the jet water conduit 16, air A is more easily released through the overflow pipe 36. As a result, fewer air bubbles are discharged into the bowl section 6, making them less noticeable to the user.

Sixth, with the flush toilet 1 according to this embodiment, flush water is guided into the jet water conduit 16, raising the water level in the jet water conduit 16 and also raising the water level in the water storage tank 4.

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 forward from the water storage tank 4, and air A is guided rearward and reliably discharged from the overflow pipe 38.

1 Flush toilet 2 Toilet body 4 Water storage tank 6 Bowl portion 8 Drain trap pipe 8a Inlet 8b Ascending pipe 8c Descending pipe 8d Top portion 10 Rim water outlet 14 Jet water outlet 16 Jet water conduit 18 Waste receiving surface 20 Rim portion 24 Water supply device 26 Drain device 28 Float switch 29 Controller 30 Rim side solenoid valve 32 Tank water supply port 34 Tank side solenoid valve 36, 52 Overflow pipe (exhaust pipe)
38, 50 Jet drain valve 40 Toilet flushing unit W Sealing surface (reservoir surface)
WL0: Still water level DWL: Dead water level A: Air

Claims (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 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. A flush toilet as described in claim 1, wherein flush water is supplied to the jet water conduit, the jet water conduit water level rises to the vicinity of the jet water drain valve, and the jet water drain valve is opened after air is discharged. A flush toilet as recited in 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. A flush toilet according to claim 3, wherein the exhaust pipe is provided inside the water storage tank. A flush toilet as described in claim 3, in which flush water is discharged from the rim spout to raise the water level in the bowl before the jet drain valve of the water storage tank is opened, thereby supplying flush water to the jet water conduit. A flush toilet as described in claim 4, wherein a portion of the flush water supplied to the water storage tank is guided from the water storage tank to the jet water conduit via the exhaust pipe before the jet drain valve of the water storage tank is opened. A flush toilet according to claim 3, wherein the exhaust pipe is positioned rearward of the jet drain valve in the front-to-rear direction.