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

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

[0004] In the flush toilet of Patent Document 1 mentioned above, the tank is positioned to have a low silhouette, and further, 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 to 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 water outlet.

[0005] Therefore, the present invention has been made to solve the problems (issues) associated with the conventional technology, and has as its object to provide a siphon jet type flush toilet that can reduce the pressure loss caused by air present between the jet drain valve and the jet water conduit flowing out from the jet spout. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a siphon jet type flush toilet, comprising a bowl portion having a waste receiving surface and a rim portion formed along the upper edge of the waste receiving surface, 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 a seal water level, a jet spout disposed below the bowl portion so as to spout flush water toward an inlet of the drain trap pipe, and a jet drain valve, the jet discharge valve has a valve body that is located lower than the upper surface of the bowl portion and higher than the seal water level, and before the jet discharge valve is opened, flushing water is supplied to the jet discharge valve to reduce any air present between the valve body of the jet discharge valve and the water surface of the jet discharge valve. According to the present invention configured in this manner, before the jet drain valve is opened, wash water is supplied to the jet water conduit to reduce the air present between the jet drain valve and the upper part of the jet water conduit, thereby reducing the pressure loss caused by this air flowing out from the jet water outlet when wash water is supplied from the water storage tank to the jet water conduit.

[0007] In the present invention, preferably, wash 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. According to the present invention configured in this way, the exhaust pipe effectively exhausts the air remaining between the jet drain valve and the water surface of the jet water conduit. Furthermore, since 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 tank. According to the present invention configured as above, since the exhaust pipe is provided inside the water storage tank, the exhaust pipe can be easily attached. The exhaust pipe also functions as an overflow pipe.

[0010] In the present invention, preferably, before the jet drain valve of the water 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 thus configured, before the jet drain valve of the water storage tank is opened, flush water is discharged from the rim water outlet to raise the water level in the bowl section, and flush water is supplied to the jet waterway, so that flush water discharged from the rim water outlet is used to wash the bowl section, and flush water can be supplied to the jet waterway by utilizing the fact that the water level in the bowl section rises due to the flush water after washing. Furthermore, water can be saved because flush water in the bowl section can be used. In addition, because flush water is supplied from the bowl section to the jet waterway, air can easily escape from the exhaust pipe, and as a result, fewer air bubbles are discharged into the bowl section, making it difficult for the user to notice the bubbles.

[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 inside the water storage tank to the jet water conduit by the exhaust pipe. According to the present invention thus configured, wash water is guided to the jet water conduit, which causes the water level in the jet water conduit to rise and also causes the water level in the water storage tank to rise.

[0012] In the present invention, the exhaust pipe is preferably disposed 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 that when the jet drain valve of the water tank is opened, cleaning water flows out of the water tank toward the front, and air is guided rearward and reliably discharged from the exhaust pipe. Effect of the Invention

[0013] According to the siphon jet flush toilet of the present invention, it is possible to reduce the pressure loss caused by air existing between the jet drain valve and the jet water conduit flowing out from the jet spout. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is a plan view showing a flush toilet according to an embodiment of the present invention. [Diagram 2] 2 is a side cross-sectional view taken along line II-II in FIG. 1. [Diagram 3] 1 is a time chart showing "rim spouting," "tank water supply," "jet spouting," and "tank water level" in a flush toilet according to an embodiment of the present invention. [Figure 4A] 1 is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" during a large flush of a flush toilet according to an embodiment of the present invention. [Figure 4B] 1 is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" in a small-flush of a flush toilet according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a side cross-sectional view of a flush toilet for illustrating the presence of air between the jet drain valve and the jet water conduit in a flush toilet according to an embodiment of the present invention. [Figure 6] 13 is a time chart showing another example of removing air present between the jet drain valve and the jet water conduit. [Figure 7] FIG. 11 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] FIG. 1 is a diagram showing the instantaneous flow rate of flush water spouted from the rim spout during a large flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe. [Figure 9B] A diagram showing the instantaneous flow rate of flush water spouted from the rim spout during a small flush of a flush toilet according to an embodiment of the present invention, the instantaneous flow rate of flush water spouted from the jet spout, and the instantaneous flow rate of flush water flowing into the inlet of the drain trap pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

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

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

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

[0020] When looking at the toilet body 2 from the front, the rim spout 10 is formed on the rear left side of the rim portion 20. The rim spout 10 spouts flushing water forward, and this flushing water swirls around the inner circumferential surface of the rim portion 20 and the shelf surface of the shelf portion 21 before flowing down to the waste receiving surface 18 and cleaning the waste receiving surface 18.

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

[0022] The jet water outlet 14 is formed in the bottom of the bowl portion 6. The jet water outlet 14 is disposed opposite the inlet 8a of the drain trap pipe 8 and is directed toward the inlet 8a of the drain trap pipe 8. The jet water outlet 14 ejects flush water toward the inlet 8a of the drain trap pipe 8, and this flush water flows into the drain trap pipe 8, activating the siphon 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 outlet 14. Flush water is supplied to the jet water conduit 16 from the water storage tank 4, and the flush water is spouted from the jet water outlet 14 by the head pressure of the flush water.

[0024] The water storage tank 4 is a gravity-fed tank that stores flush water to be used for jet spouting and supplies it to the jet spout 14. Flush water is stored in the water storage tank 4 up to 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-silhouette type toilet.

[0025] Provided within the water storage tank 4 are a water supply device 24 which supplies flush water into the water storage tank 4, a drainage device 26 which supplies or stops the flush water stored in the water storage tank 4 to the jet water conduit 16, and a float switch 28 which detects when the flush water level in the water storage tank 4 has reached the water stop level (WLO). Also provided outside the water storage tank 4 are a controller 29 which 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) which transmits an operation signal in response to operation by the user.

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

[0027] The drainage device 26 is equipped with 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 with an electric driving force. The upper and lower ends of this overflow pipe 36 are open so that overflowing water from the water storage tank 4 can 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 port 4a of the water storage tank 4. The toilet flushing unit 40 is driven by commands from the controller 29 based on an operation signal from the user.

[0028] As described above, the flush toilet 1 is a low-silhouette type toilet, but more specifically, as shown in FIG. 2, the valve body 38a of the jet drain valve 38 is positioned lower than the upper surface of the bowl portion 6 (the 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, the float switch 28, the rim side solenoid valve 30, the tank side solenoid valve 34, and the toilet flushing unit 40, and is capable of sending and receiving various signals. The controller 29 receives a flush start signal for a large flush or small flush from the operation unit, and drives or stops the rim side solenoid valve 30, the tank side solenoid valve 34, and the toilet flushing unit 40 based on a flush sequence stored in advance.

[0030] Next, "rim water spouting," "tank water supply," "jet water spouting," and "tank water level" in a flush toilet 1 according to this embodiment will be explained with reference to Figure 3. Figure 3 is a time chart showing "rim water spouting," "tank water supply," "jet water spouting," and "tank water level" in a flush toilet according to an embodiment of the present invention.

[0031] Here, "rim spouting" refers to spouting flush water from the rim spout 10, "tank water supply" refers to supplying water to the water storage tank 4, "jet spouting" refers to spouting flush water from the jet spout 14, and "tank water level" refers to the level of flush water in the water storage tank 4.

[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, at time t1 the rim-side solenoid valve 38 turns ON, commencing rim spouting, which supplies water to the rim water conduit 12 and spouts flush water from the rim spout 10. This rim spouting continues until time t5.

[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 water spouting port 14. This jet water spouting ends at time t4. When jet water spouting is being performed from time t2 to time t4, rim water spouting is also being performed at the same time.

[0034] Here, as is clear from Figure 3, for convenience, rim spouting from time t1 when rim spouting begins to time t2 when jet water spouting begins is referred to as "front rim spouting," rim water spouting from time t2 to time t4 when jet water spouting is performed is referred to as "middle rim spouting," and rim water spouting from time t4 when jet water spouting ends to time t5 when rim spouting ends is referred to as "rear rim spouting." Also, as mentioned above, "jet water spouting" is performed from time t2 to time t4.

[0035] Next, as shown in Figure 3, float switch 28 was ON at time t2 when jet water spouting began because the flush water level in the water storage tank 4 was at the stop water level, but then at time t3, the flush water level in the water storage tank 4 drops below the stop water level, so it turns OFF. This OFF state of float switch 28 continues until time t7.

[0036] Also, at time t6, the tank-side solenoid valve 34 is opened and turned ON, starting tank water supply to the storage tank 4, and the tank water supply ends at time t8. As a result of this tank water supply starting at time t6, the flush water level in the storage tank 4 rises, which causes the float switch 28 to return to ON at time t7 as the flush water level in the storage tank 4 rises to the stop water level, entering a full water state.

[0037] The large flush has been explained using Figure 3, but the small flush also applies to the time chart in Figure 3. Note that, as will be described later, the large flush and small flush have different water discharge times and water discharge volumes.

[0038] Next, the spouting times and water spouting volumes of rim spouting and jet spouting in the large flush and small flush will be explained with reference to Figures 4A and 4B. Figure 4A is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" in the large flush of a flush toilet according to an embodiment of the present invention, and Figure 4B is a table showing the water spouting times and water spouting volumes of "front rim spouting," "middle rim spouting," "rear rim spouting," and "jet spouting" in the small flush of a flush toilet according to an embodiment of the present invention.

[0039] As shown in Fig. 4A, in the case of large flush, the front rim water spouting time is 1.9 seconds (s) and the water spouting volume is 0.41 liters (L), the middle rim water spouting time is 2.4 seconds (s) and the water spouting volume is 0.52 liters (L), and the rear rim water spouting time is 6.1 seconds (s) and the water spouting volume is 1.32 liters (L). Also, the jet water spouting time is 2.4 seconds (s) and the water spouting volume is 2.31 liters (L).

[0040] As is clear from Figure 4A, in the case of large flush, the water discharge time of the front rim water discharge (1.9 seconds) is shorter than the water discharge time of the rear rim water discharge (6.1 seconds). Furthermore, the total water discharge time of the front rim water discharge and the middle rim water discharge (1.9 seconds + 2.4 seconds) is shorter than the water discharge time of the rear rim water discharge (6.1 seconds).

[0041] Similarly, as shown in Figure 4B, in the case of a small flush, the front rim water spouting time is 1.4 seconds (s) and the water spouting volume is 0.31 liters (L), the middle rim water spouting time is 1.7 seconds (s) and the water spouting volume is 0.37 liters (L), and the rear rim water spouting time is 7.6 seconds (s) and the water spouting volume is 1.64 liters (L). Also, the jet water spouting time is 1.7 seconds (s) and the water spouting volume is 1.50 liters (L).

[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 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).

[0043] Next, the presence of air between the jet drain valve and the jet water conduit in a flush toilet 1 according to this embodiment will be explained with reference to 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 water conduit 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 state, flush water discharged by the rear rim spouting 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 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 spouting, 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 outlet 14, this air A mixes with the jet water, generating a popping sound and also causing a 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 described with reference to Fig. 3. As shown in Fig. 3, after the standby state, at time t1, the rim-side solenoid valve 30 opens, flush water is discharged from the rim water outlet 10 (i.e., the above-mentioned pre-rim water outlet is performed), and this flush water is supplied to the bowl section 6, the water seal surface (pooled water surface) W rises from the water seal level, and the water level in the bowl section 6 becomes higher than the water seal level. At this time, flush water in the bowl section 6 is supplied from the jet water outlet 14 into the jet water conduit 16, and the water level in the jet water conduit 16 rises 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 water outlet 10 is preferably 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, since the overflow pipe 36 is disposed so as to extend from below the valve body 38a of the jet drain valve 38 to above the stop water level, the water level in the jet water conduit 16 rises, and the 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 wash water is discharged from the rim outlet 10 at time t1, the jet drain valve 38 is opened at time t2, so that the wash 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 wash water is discharged from the jet outlet 14.

[0048] In the first example described above, the rim-side solenoid valve 30 opens and flush water is discharged from the rim water outlet 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, the 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 Fig. 6, after the standby state, the tank solenoid valve 34 is opened between time t11 and time t12, 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 the water level in the water storage tank 4 rises from the stop water level to the upper end of the overflow pipe 36 due to this water supply, 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 tank 4 has ended, 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, thereby reducing pressure loss 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 include an overflow pipe, and only lightly closes the drain port of the water storage tank 4. Furthermore, the overflow pipe 52 is disposed 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, where flush water has accumulated in bowl portion 6 up to seal water level W, and flush water has also accumulated in jet conduit 16 up to the same height as the seal water level. At this time, as described above, air A is retained between valve body 38a of jet drain valve 38 in water storage tank 4 and the upper part of jet 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 the trapped air A is discharged 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 (seal water) remaining in bowl portion 6 and flush water from rim water spouting combine with flush water from jet water spouting, and a large flow rate of flush water flows into drain trap pipe 8, causing a strong siphon effect and discharging waste.

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

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

[0058] Next, as shown in Fig. 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 the original standby state as shown in Fig. 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 flushing water discharged from the jet water outlet 14, the dotted line indicates the instantaneous flow rate of flushing water discharged from the rim water outlet 10, and the solid line indicates the instantaneous flow rate of flushing water flowing into the inlet 8a of the drain trap pipe 8.

[0061] As shown in Figure 9A, in a large flush, at time t2, the drain valve 38 is opened and flush water in the water storage tank 4 passes through the jet water conduit 17 and is spouted from the jet water spouting port 14. The instantaneous flow rate of the jet water spouting, shown by the dashed line, increases suddenly immediately after it starts and then remains approximately constant. At time t4, the drain valve 48 is closed, which causes the instantaneous flow rate of the jet water spouting to also decrease.

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

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

[0064] After the 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 siphoning action can be generated and continued without increasing the amount of water stored in the water storage tank 4, thereby achieving water conservation.

[0065] Next, as shown in Figure 9B, in the small flush, at time t2, the jet drain valve 38 is opened and flush water in the water storage tank 4 passes through the jet water conduit 17 and is spouted from the jet water spouting port 14. The instantaneous flow rate of the jet water spouting, shown by the dashed line, increases suddenly immediately after it starts and then remains approximately constant. At time t4, the jet drain valve 38 is closed, which causes the instantaneous flow rate of the jet water spouting to also decrease.

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

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

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

[0069] Next, the effects achieved by the flush toilet according to the embodiment of the present invention described above will be explained. Firstly, 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 that 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, it is possible to reduce the amount of air that flows out as air bubbles to the water sealing surface (reserved water surface) W of the bowl surface 6, so cleaning by these air bubbles is not adversely affected.

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

[0073] Fifth, according to 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, and flush water is thereby supplied to the jet water conduit 12, so that the flush water discharged from the rim spout 10 flushes the bowl section 6, and the flush water after this flush rises the water level in the bowl section 6, making it possible to supply flush water to the jet water conduit 16. Furthermore, water can be 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 it harder for the user to notice the air bubbles.

[0074] Sixth, with the flush toilet 1 of 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, according to 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 is reliably discharged from the overflow pipe 38. [Explanation of symbols]

[0076] 1 flush toilet 2 Toilet bowl body 4. Water tank 6 Bowl section 8 Drain trap line 8a entrance 8b Ascending Pipe 8c descending pipe 8d top 10 Rim Spout 14 Jet outlet 16 Jet Waterway 18 Waste receiving surface 20 Rim section 24 Water supply equipment 26 Drainage system 28 Float switch 29 Controller 30 Rim side solenoid valve 32 Tank water inlet 34 Tank side solenoid valve 36, 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 type 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 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 located between the ascending pipe and the descending pipe and defining a seal water level; a jet water outlet disposed below the bowl portion so as to discharge flush water toward an inlet of the drain trap pipe; a water storage tank that is equipped with a jet drain valve and stores flush water to be supplied to the jet water outlet; a jet water conduit that connects the water storage tank and the jet water outlet, and 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 for controlling the rim water spouting from the rim water spouting port and the jet water spouting from the jet water spouting port, The jet 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, 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 of the jet waterway.

2. 2. The flush toilet according to claim 1, wherein flush water is supplied to the jet water conduit, and the jet drain valve is opened after the water level in the jet water conduit has risen to the vicinity of the jet drain valve and air has been discharged.

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 described 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. 4. The flush toilet according to claim 3, wherein the exhaust pipe is disposed rearward of the jet drain valve in the front-to-rear direction.

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