Flush toilet bowl

Abstract

To provide a flush toilet bowl capable of, when cleaning a toilet bowl in a case of emergency such as blackout, surely performing toilet bowl cleaning, while curbing heightening of a required water level of cleaning water in a bowl part and preventing water leakage outside the bowl, by suppressing air retaining on a downstream side relative to a sealing water surface in a drain trap pipeline of the toilet bowl body by filling the space with cleaning water.SOLUTION: A flush toilet bowl 1 of the present invention includes a toilet bowl body 2 and an on-off valve for water retention 50 that opens / closes a drain trap pipeline 12 of the toilet bowl body. The on-off valve for water retention is disposed on a downstream side relative to a sealing water surface WL0 in the drain trap pipeline, and to a region A1 between the sealing water surface in the drain trap pipeline and the on-off valve for water retention, an air vent tube 54 capable of venting air A0 in the region to outside is connected.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a flush toilet, and more particularly to a flush toilet that is flushed with flush water to expel waste. [Background technology]

[0002] Conventionally, as a flush toilet that is flushed with flush water to expel waste, so-called hybrid flush toilets have been known, for example as described in Patent Document 1, in which flush water supplied under direct pressure from the water mains is supplied directly to the rim spout of the toilet body, and flush water that is temporarily supplied and stored in a tank is supplied to the jet spout of the toilet body by a pump. Such conventional flush toilets are equipped with a ceramic toilet body equipped with a bowl and a drain trap pipe, and a drain socket connected to the downstream end of the drain trap pipe of the toilet body. An on-off valve is provided inside the drain socket to open and close the flow path. This on-off valve is connected to an operating part that is opened and closed by the user in emergencies such as water outages due to power outages or pump failures. When the toilet is flushed normally, the drain socket's opening and closing valve is kept open, allowing waste in the bowl of the toilet body to be discharged from the drain trap pipe through the drain socket and into an external drain pipe. On the other hand, when flushing the toilet in an emergency, the user closes the drain socket valve using the operating unit, and then flush water is supplied to the bowl of the toilet body from an external bucket or pail, or the amount of flush water required for flushing is supplied into the bowl from the rim spout by supplying water using direct water pressure, etc. After that, the drain socket valve is operated to the open state again, so that waste in the bowl of the toilet body is discharged from the drain trap pipe through the drain socket to an external drain pipe, even in an emergency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-227852 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional flush toilets described above, air pockets form in the area between the water sealing surface in the drain trap pipe behind the bowl portion of the toilet body and the opening and closing valve of the drain socket when it is in the closed state, particularly when the toilet is flushed during an emergency such as a power outage. Therefore, due to the internal pressure (air pressure) caused by the air accumulation in this area, even if additional flushing water is supplied from the bowl side, flushing water is less likely to accumulate in the area downstream of the sealing surface in the drain trap pipe, while the flushing water level on the bowl side becomes higher the more water is supplied. As a result, the required water level for flushing the toilet in an emergency becomes higher in the bowl portion of the toilet body, which poses the risk of the flushing water in the bowl portion of the toilet body leaking to the outside (so-called "outside the machine leakage"). Furthermore, in such a situation, some users may be under the misconception that the water level in the bowl portion of the toilet body has risen higher than necessary, and as the user becomes anxious, they may open the drain socket opening / closing valve earlier than necessary while the flush water level in the bowl portion is rising to the required water level, resulting in a problem of not being able to ensure a sufficient amount of flush water for flushing the toilet. Therefore, in recent years, a pressing issue has been how to ensure that flush water is stored in the area between the sealing surface in the drain trap pipe of the toilet body and the on-off valve in the drain socket downstream of it, thereby securing a larger amount of flush water needed for emergency flushing while preventing water leakage outside the machine.

[0005] Therefore, the present invention has been made to solve the problems of the conventional technology and issues that have been required in recent years, and aims to provide a flush toilet that, when flushing the toilet in an emergency such as a power outage, can reliably perform toilet flushing while preventing the required water level of flushing water in the bowl from increasing and preventing water leakage outside the machine by suppressing air pockets downstream of the sealing surface in the drain trap pipe of the toilet body and filling it with flushing water. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a flush toilet that is flushed with flushing water to discharge waste, the flush toilet having a toilet body including a bowl portion that receives waste and a drain trap pipe that forms a drainage flow path that discharges the waste within the bowl portion, and a water collection opening / closing valve that allows water to be collected in the bowl portion by opening, closing, and closing the drain trap pipe, the drain trap pipe having an inlet portion connected to the below of the bowl portion, a curved pipe that extends from the inlet portion to a lower end at the rear and below and then rises to a top at the rear and above, and a descending pipe that descends from the top of the curved pipe to an outlet portion at the rear and below, and forms a water sealing surface in the area upstream of the top, the water collection opening / closing valve is provided downstream of the water sealing surface of the drain trap pipe, and an air vent pipe is connected between the water sealing surface in the drain trap pipe and the water collection opening / closing valve to vent air within that area to the outside. In the present invention configured in this manner, when flushing the toilet, the water reservoir valve is normally kept open, whereas in an emergency such as a power outage, the water reservoir valve is closed before starting the toilet flush. At this time, particularly when flushing the toilet in an emergency such as a power outage, if flushing water is supplied into the bowl portion of the toilet body with the water storage valve closed in advance, the flushing water in the bowl portion will flow into the curved pipe from the inlet of the drain trap pipe, and even if air accumulates in the area between the sealing surface in the drain trap pipe and the water storage valve, the air can be quickly bled using the air vent pipe. This ensures that air accumulation is prevented and the area upstream of the water storage valve in the drain trap pipe is quickly filled with flushing water before emergency toilet flushing begins, thereby ensuring a larger amount of flushing water accumulates in the area upstream of the water storage valve in the drain trap pipe. Therefore, it is possible to suppress an increase in the required water level within the bowl portion of the toilet body required for emergency toilet flushing. This makes it possible to prevent flush water in the bowl part of the toilet body from leaking to the outside in an emergency (so-called "outside the machine leakage"). Also, when starting a toilet flush in an emergency, it is possible to prevent the user from becoming anxious while the flush water level rising in the bowl part of the toilet body is rising to the required water level, causing the user to open the water reservoir opening / closing valve too early, resulting in an insufficient toilet flush. As a result, when flushing the toilet in an emergency such as a power outage, air pockets downstream of the water seal surface in the drain trap pipe of the toilet body are suppressed and filled with flushing water, thereby preventing the required water level of flushing water in the bowl from increasing and preventing water leakage outside the machine, thereby ensuring that the toilet is flushed reliably.

[0007] In the present invention, preferably, the air vent pipe has an inlet connected between the water sealing surface in the drain trap pipeline and the water reservoir opening / closing valve, and an outlet connected to the drainage flow path downstream of the water reservoir opening / closing valve. In the present invention configured in this manner, the inlet of the air vent pipe is connected between the sealing surface in the drain trap pipeline and the water storage valve, while the outlet of the air vent pipe is connected to the drainage flow path downstream of the water storage valve, so that odorous air in the area between the sealing surface and the water storage valve in the drain trap pipeline can be reliably discharged from the inlet to the outlet of the air vent pipe into the drain pipe. Therefore, it is possible to reliably prevent air containing bad odors in the area between the sealing surface and the water storage opening / closing valve in the drain trap pipe from flowing back into the area upstream of the water storage opening / closing valve in the drain trap pipe or into the bowl portion of the toilet body.

[0008] In the present invention, it is preferable that the toilet further includes a drain socket connected to the outlet portion of the drain trap pipe, the drain socket forming a drain flow path downstream of the water reservoir opening / closing valve and being assembled to a part of the toilet body, and the air vent pipe has an inlet connected between the sealing surface in the drain trap pipe and the water reservoir opening / closing valve and an outlet connected to the drain flow path of the drain socket. In the present invention configured in this manner, the inlet of the air vent pipe is connected between the sealing surface in the drain trap pipe and the water sump opening / closing valve, while the outlet of the air vent pipe is connected downstream of the water sump opening / closing valve in the drain socket assembled to a part of the toilet body, so that odorous air in the area between the sealing surface and the water sump opening / closing valve in the drain trap pipe can be reliably discharged from the inlet to the outlet of the air vent pipe into the drainage flow path of the drain socket. In addition, because the outlet of the air vent pipe is connected to the drainage flow path of the drain socket, the air vent pipe can be easily attached within the area of ​​the toilet body, eliminating the need for additional work on an external drain pipe located behind the wall or under the floor on which the toilet body is installed.

[0009] In the present invention, the outlet of the air vent pipe is preferably disposed adjacent to the water reservoir on-off valve in a closed state. In the present invention configured in this manner, the outlet of the air vent pipe is positioned adjacent to the water reservoir valve in the closed state, so that when the water reservoir valve in the closed state is opened, the cleaning water passing through the water reservoir valve can close the outlet of the air vent pipe. In addition, because the outlet of the air vent pipe is filled with flushing water that passes through the water reservoir on-off valve, the air vent pipe does not suck in air from its outlet, and therefore air is not discharged from the inlet of the air vent pipe. This prevents air from being entrained in the flushing water used to flush the toilet, and prevents a decrease in flushing performance. Therefore, for example, in the case of a so-called "siphon type flush toilet" that uses the siphon action to suck up waste within the bowl portion of the toilet body and then discharge it to the outside all at once through the drain trap, during normal flushing, it is possible to prevent the flush water passing through the open water reservoir opening / closing valve from sucking in air flowing out from the inlet of the air vent pipe, which could make it difficult to maintain the siphon action. In addition, even in an emergency such as a power outage, if a siphoning effect occurs when the water storage valve is closed to store water in the drain trap pipeline and then the water storage valve is opened, the flushing water passing through the open water storage valve will close the outlet of the air vent pipe and air will no longer be sucked in from the outlet of the air vent pipe, thereby preventing the siphoning effect from becoming difficult to sustain.

[0010] In the present invention, it is preferable that the toilet further comprises a flushing water supply device having a water storage tank for storing flushing water and supplying flushing water to the toilet body, and an overflow flow path for overflowing flushing water that exceeds the specified water level in the water storage tank, the outlet of the overflow flow path being connected between the sealing surface in the drain trap pipe and the water storage opening / closing valve, and the inlet or top of the air vent pipe being positioned at a higher position than the top of the drain trap pipe. In the present invention configured in this manner, the outlet of the overflow flow path, which overflows flushing water that exceeds the specified water level in the storage tank of the flushing water supply device, is connected between the sealing surface of the drain trap pipe and the water storage opening / closing valve, so that the opening cross-sectional area of ​​the outlet of the overflow flow path can be set relatively large when connected to the drain trap pipe. Therefore, before emergency toilet flushing begins, the overflow flush water flowing out from the outlet of the overflow flow path can be quickly pooled in the area between the sealing surface of the drain trap pipe and the water pool opening / closing valve. In addition, since the inlet or top of the air vent pipe is positioned at a higher position than the top of the drain trap pipe, even if air accumulates in the area between the sealing surface and the water storage opening / closing valve in the drain trap pipe, the air can be bled quickly and reliably through the air vent pipe.

[0011] In the present invention, the inlet of the air vent pipe is preferably connected to the overflow passage. In the present invention thus configured, the inlet of the air vent pipe is connected to the overflow passage, so that air within the overflow passage can also be easily vented by the air vent pipe. This improves the overflow performance in the overflow flow path, and also enables the overflow flushing water flowing out from the outlet of the overflow flow path to be quickly stored in the area between the sealing surface in the drain trap pipe and the water storage opening / closing valve before emergency toilet flushing begins. Incidentally, when collecting water in the drain trap pipe during an emergency such as a power outage, if the overflow passage is not provided above the drain trap pipe, it is necessary to connect the inlets of at least two air vent pipes to the upper parts of the drain trap pipe and the overflow passage, etc., and the need for multiple air vent pipes complicates the structure and increases manufacturing costs. On the other hand, if the overflow passage is provided above the drain trap pipe, the inlet of the air vent pipe can be connected to the upper part of the drain trap pipe and the upper part of the overflow passage, so that a single air vent pipe can be used, simplifying the structure and reducing manufacturing costs.

[0012] In the present invention, it is preferable that the device further comprises an air vent valve which is integrally provided with the water reservoir valve for opening and closing the outlet of the air vent pipe, and this air vent valve is configured to be linked to the water reservoir valve so that when the water reservoir valve is open, the outlet of the air vent pipe is closed, and when the water reservoir valve is closed, the outlet of the air vent pipe is open. In the present invention thus configured, the air vent valve which is provided integrally with the water reservoir valve and opens and closes the outlet of the air vent pipe can be linked to the water reservoir valve. Furthermore, by closing the outlet of the air vent pipe when the water reservoir valve is open, for example, in the case of a so-called "siphon type flush toilet," this prevents the flush water passing through the open water reservoir valve during normal flushing from drawing in air flowing out from the inlet of the air vent pipe, making it difficult to maintain the siphon action. On the other hand, when the water reservoir valve is closed, the air vent valve keeps the outlet of the air vent pipe open, so that even if air accumulates in the area between the sealing surface and the water reservoir valve in the drain trap pipeline, the air can be quickly bled through the air vent pipe.

[0013] In the present invention, the air vent pipe is preferably equipped with a check valve which is configured to allow air to pass from the inlet side to the outlet side of the air vent pipe while blocking air from flowing from the outlet side to the inlet side of the air vent pipe. In the present invention configured in this manner, the air vent pipe is equipped with a check valve, which allows air to pass from the inlet side to the outlet side of the air vent pipe, while preventing air from flowing from the outlet side to the inlet side of the air vent pipe (reverse air flow). Therefore, the air flow in the air vent pipe can be restricted to one direction to prevent backflow, eliminating air accumulation in the area between the sealing surface and the water storage valve in the drain trap pipe before emergency toilet flushing begins, and ensuring a larger amount of flush water to accumulate in the area upstream of the water storage valve. Effect of the Invention

[0014] According to the flush toilet of the present invention, when flushing the toilet in an emergency such as a power outage, air pockets downstream of the water sealing surface in the drain trap pipe of the toilet body are suppressed and filled with flushing water, thereby preventing the required water level of flushing water in the bowl from increasing and preventing water leakage outside the machine, thereby ensuring that the toilet is flushed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a plan view of a flush toilet according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 1 is a schematic diagram showing the overall structure of a flush toilet according to a first embodiment of the present invention. [Figure 4] FIG. 1 is a diagram showing the overall configuration of a flush toilet according to a first embodiment of the present invention, and a schematic diagram of the process for supplying and draining flush water. [Diagram 5] 2 is a cross-sectional view taken along line VV in FIG. 1. [Figure 6] FIG. 1 is a perspective view of a flush water supply device for a flush toilet according to a first embodiment of the present invention, seen diagonally from the rear. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8A] FIG. 1 is a schematic diagram showing a flush toilet according to a first embodiment of the present invention in an emergency state before water is filled. [Figure 8B] FIG. 2 is a schematic diagram showing the flush toilet according to the first embodiment of the present invention in an emergency state when water is being stored. [Figure 8C]FIG. 1 is a schematic diagram showing a flush toilet according to a first embodiment of the present invention in an emergency flushing state. [Figure 9A] FIG. 13 is an enlarged cross-sectional view of the outlet and its downstream portion of the drain trap pipe of a flush toilet according to a second embodiment of the present invention, showing the state in which the water reservoir on-off valve is open. [Figure 9B] FIG. 13 is an enlarged cross-sectional view of the outlet and its downstream portion of the drain trap pipe of a flush toilet according to a second embodiment of the present invention, showing the state in which the water reservoir on-off valve is closed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A flush toilet according to a first embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1 is a plan view of a flush toilet according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Furthermore, Fig. 3 is a schematic diagram showing the overall structure of a flush toilet according to this embodiment. First, as shown in Figures 1 and 2, the flush toilet 1 according to the first embodiment of the present invention is a so-called "floor-mounted flush toilet", in which the toilet body 2 is placed in contact with the floor surface F. Furthermore, as shown in Figures 1 and 2, the floor-standing flush toilet 1 of this embodiment comprises a ceramic toilet body 2 that is placed in contact with the floor surface F, and a flush water supply device 4 that supplies flush water to this toilet body 2.

[0017] Next, as shown in Figures 1 to 3, the toilet body 2 specifically comprises a bowl portion 10 including a waste receiving surface 6 for receiving waste and a rim portion 8 formed on the upper edge of this waste receiving surface 6. The toilet body 2 also includes a drain trap pipe 12 that forms a drain passage for discharging waste from within the bowl portion 10.

[0018] Furthermore, as shown in Figures 2 and 3, more specifically, the drain trap pipe 12 forms a curved pipe line that, from the upstream side to the downstream side, its inlet portion 12a is connected to the lower portion of the bowl portion 10, extends from this inlet portion 12a to the rear and downward lowest end portion 12b, then rises to a rear and upper top portion 12c, and descends rear and downward from this top portion 12c. As shown in Figs. 2 and 3, a water seal (water seal surface WL0) is formed in the drain trap pipe 12 in a region upstream (forward) of the top 12c. Furthermore, in the flush toilet 1 of this embodiment, the outlet portion 12d on the downstream (rear) side of the curved pipe of the drain trap pipe 12 is connected via a drain socket 14 to a drain pipe 16 on the back side of the wall W (or the front wall W of the cabinet C), resulting in a so-called "wall drainage" drainage configuration.

[0019] 2 and 3, the toilet body 2 is equipped with a rim spouting section 18 including a rim spouting outlet 18a provided in the rim section 8. The rim spouting outlet 18a is directed toward the inside of the bowl section 10. As a result, flush water supplied from the flush water supply device 4 to the toilet body 2 is spouted W1 (rim spouting W1) from the rim spouting port 18a of the rim spouting section 18 towards the inside of the bowl section 10. That is, in this embodiment, toilet flushing is performed only by the rim water spout W1 spouted only from the rim water spouting port 18a, that is, toilet flushing by "100% rim water spouting flush" is performed.

[0020] Next, the flush water supply device 4 in the flush toilet 1 of the present embodiment will be explained in detail with reference to Figs. Fig. 4 is a diagram showing the overall configuration of a flush toilet according to this embodiment, and the flush water supply and drainage process thereof. Also, Fig. 5 is a cross-sectional view taken along line VV in Fig. 1. Furthermore, Fig. 6 is a perspective view of the flush water supply device for a flush toilet according to this embodiment, seen diagonally from behind, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. First, as shown in Figures 1 to 3, the flush water supply device 4 includes, from an external water source 22, such as a water main, toward the downstream side, a stopcock 24, a valve unit 26, a water supply section 28, a water storage tank 30, a pump 32, a rim-side supply pipe 36, and an overflow pipe 40. First, although a detailed description of the valve unit 26 will be omitted, the valve unit 26 is equipped with a constant flow valve (not shown), a diaphragm valve (not shown) which is an opening / closing valve provided downstream of the constant flow valve (not shown), and a solenoid valve (not shown) which opens and closes this opening / closing valve (diaphragm valve), etc. For example, cleaning water W0 (supply water W0) supplied from water supply source 22 through stop valve 24 at the water supply pressure of a water supply or the like passes through a constant flow valve (not shown) of valve unit 26 to adjust the flow rate to a constant level when a diaphragm valve (not shown) is opened by the operation of an electromagnetic valve (not shown) of valve unit 26, and then passes through the diaphragm valve (not shown). As a result, flush water W0 that has passed through valve unit 26 is supplied from water supply section 28 into water storage tank 30.

[0021] Incidentally, the flush water supply device 4 is equipped with a controller (not shown) that controls the operation of the pump 32, and a float switch 42 that detects the water level in the water storage tank 30. Furthermore, the opening and closing operation of the solenoid valve (not shown) of the valve unit 26 is controlled by a controller (not shown) based on the water level in the water storage tank 30 detected by a float switch 42. Furthermore, the operation of the pump 32 is also controlled by a controller (not shown) based on the water level in the water storage tank 30 detected by a float switch 42. For example, when the water level in the water tank 30 detected by the float switch 42 is below a predetermined level, the solenoid valve (not shown) of the valve unit 26 opens and the diaphragm valve (not shown) of the valve unit 26 opens, thereby supplying water W0 from the water supply section 28 to the water tank 30.

[0022] Next, as shown in Figures 3, 5 and 6, the flush water supplying device 4 is provided with a toilet body side connecting pipe 44 that forms a pipe 44a (toilet body side connecting pipe 44a) that extends downstream from the first outlet 30a, which is below the specified water level (upper limit water level or full water level) WL1 of the water storage tank 30, via the pump 32. As a result, when the pump 32 operates under the control of a controller (not shown) based on the water level in the water tank 30 detected by the float switch 42, the flushing water in the water tank 30 flows out from the first outlet 30a to the toilet body side connecting pipe 44a, is sucked up by the pump 32 and supplied to the rim water channel 36a from the rim side supply pipe 36. As a result, flush water in the water storage tank 30 passes through the pump 32 and is discharged from the rim spout 18a of the toilet body 2 as rim spout W1. Then, as shown in Figure 3, when the water level in the water storage tank 30 reaches a predetermined water level (stopping water level) WL2 which is lower than the specified water level WL1, the solenoid valve (not shown) of the valve unit 26 closes based on the detection of the float switch 42 and the diaphragm valve (not shown) closes, thereby stopping the water supply from the water supply section 28 and stopping the pump 32.

[0023] Next, as shown in Figures 3, 5 and 6, the water tank 30 is provided with an overflow side connecting pipe 46 that extends from its interior to the second outlet 30b above the specified water level WL1 of the water tank 30 and is connected to the overflow pipe 40. The overflow side connecting pipe 46 forms a pipe line 46a (overflow side connecting pipe line 46a) that connects the inside of the water storage tank 30 with the flow path 40a of the overflow pipe 40 (overflow flow path 40a). Also, as shown in Figures 2, 3, 5 and 7, the drain trap pipe 12 of the toilet body 2 is provided with a connecting member 12e that connects the downstream side of the drain trap pipe 12 and the upstream side of the drain socket 14, and this connecting member 12e forms a descending pipe 12f that descends from the top 12c of the drain trap pipe 12 to the downstream side (rear and downward). Furthermore, as shown in Figures 2, 3, 5 and 7, the overflow pipe 40 of the cleaning water supplying device 4 connects the outlet (second outlet 30b) of the overflow side connecting pipe 46 to the upper surface of the descending pipe 12f of the drain trap pipe 12. As a result, flush water W3 (overflow flush water W2) that has exceeded the specified water level WL1 in the water storage tank 30 is caused to overflow by the overflow pipe 40 into the descending pipe 12f of the drain trap pipe 12.

[0024] As shown in Figures 2, 3, 5 and 7, the outlet of the overflow side connecting pipe 46a corresponds to the second outlet 30b and essentially serves as the overflow port 30b, and a flapper valve 48 is provided in this overflow port 30b so as to be capable of being opened and closed. During normal use, when the toilet is not being flushed, the flapper valve 48 keeps the overflow port 30b normally closed. Also, when flushing the toilet, the flapper valve 48 closes the overflow port 30b to prevent backflow of water in the drain trap pipe 12 and suppress a decrease in flushing ability. In addition, even if a drain blockage occurs in the drain trap pipe 12, the flapper valve 48 closes to prevent backflow of drainage from the descending pipe 12f side of the drain trap pipe 12 through the overflow flow path 40a toward the overflow side connecting pipe 46a. It is also possible to prevent the intrusion of pests from the overflow flow path 40a into the overflow side connecting pipe 46a. Furthermore, in the event of an abnormality such as a malfunction of the flush water supply device 4 or shutdown due to a power outage, when the water level in the water storage tank 30 rises above the specified water level WL1, the fluid force of the flush water causes the flapper valve 48 to open the overflow port 30b. This allows the flush water W2 flowing out from the overflow port 30b to flow (overflow) into the descending pipe 12f of the drain trap pipe 12 in the toilet body 2 without backflowing from the overflow flow path 40a.

[0025] Next, as shown in Figures 3, 5 and 6, the water supply section 28 of the cleaning water supply device 4 comprises a water supply pipe 28a connected to the valve unit 26 upstream of it, a water supply nozzle 28b connected to this water supply pipe 28a, a water supply port 28c provided at the downstream end of this water supply nozzle 28b, and a water receiving housing 28d that receives the cleaning water supplied from this water supply port 28c. This water receiving housing 28d is communicatively connected to the upper part of the water storage tank 30, and the flushing water W0 supplied into the water receiving housing 28d from the water supply port 28c is first received in the water receiving housing 28d, and then flows into the water storage tank 30 through the communication passage 28e between the water receiving housing 28d and the water storage tank 30. In addition, an opening 28f located above the overflow port 30b of the water storage tank 30 is provided in a portion of the side wall of the water receiving housing 28d. Furthermore, the bottom end 28g of the opening 28f of the water receiving housing 28d is located below the water supply port 28c. As a result, in the unlikely event of a power outage or a malfunction of the pump 32, flush water in the water storage tank 30 rises into the water receiving housing 28d and reaches the opening 28f, the flush water will leak outside the machine from this opening 28f, allowing the user to become aware of the emergency caused by the leak. Furthermore, when the flush water supply device 4 of the flush toilet 1 of this embodiment is to comply with overseas specifications such as those of Europe, the opening 28f of the water receiving housing 28d can provide an opening that is connected to the atmosphere above the overflow port 30b of the water storage tank 30 and below the water supply port 28c, and it is possible to provide a space (air gap) between this water supply port 28c and the lower end 28g of the opening 28f without submerging the water supply port 28c of the water supply section 28.

[0026] Next, the drain socket 14 will be described in detail with reference to Figs. As shown in Figures 2 to 7, the drain socket 14 has a main body portion 14a connected to the outlet portion 12d of the drain trap pipe line 12 of the toilet body 2, and this main body portion 14a connects the outlet portion 12d of the descending pipe line 12f of the drain trap pipe line 12 to the inlet portion 16a of the drain pipe 16 behind it. Furthermore, the main body 14a has a flow path (internal flow path) 14b formed therein, and the upstream end of this internal flow path 14b is an inlet 14c connected to the outlet 12d of the downflow pipe 12f of the drain trap pipe 12. The drain socket 14 also includes a water reservoir opening / closing valve 50 that is openably and closably provided for the inlet 14c of the internal flow path 14b in the main body 14a and the outlet 12d of the descending pipe 12f of the drain trap pipe 12. As a result, the drain socket 14 forms a drain flow path 14b downstream of the water reservoir opening / closing valve 50 and is attached to a part of the toilet body 2. Furthermore, the water reservoir opening / closing valve 50 includes a rotating shaft 50a, a valve body 50b that is integrally provided on the rotating shaft 50a, and a mechanism 50c that allows the rotating shaft 50a to rotate. An operating unit 52 that allows the user to manually open and close the valve in an emergency such as a power outage is connected to the mechanism 50c. Here, in Figure 7, the water storage opening / closing valve 50 is shown by a solid line when the outlet 12d of the drain trap pipe 12 is closed, and by a dotted line when it is open, but under normal circumstances, the valve body 50b rotates in the rotation direction R1 around the rotation axis 50a, keeping the outlet 12d of the drain trap pipe 12 always open. On the other hand, as shown in Figure 7, in the event of an emergency such as a power outage, the user can manually close the water storage valve 50 by operating the operating part 52, thereby allowing water to be stored in the flow path within the drain trap pipe 12 of the toilet body 2 upstream of the water storage valve 50 and in the storage part within the bowl section 10.

[0027] Next, as shown in FIGS. 2, 3, and 5 to 7, the water reservoir on-off valve 50 is provided on the downstream side of the water sealing surface WL0 of the drain trap pipe 12. In addition, an air vent pipe 54 is connected between the water sealing surface WL0 in the drain trap pipe line 12 and the water reservoir opening / closing valve 50, which can vent the air in the area A1 to the outside. The air vent pipe 54 has its inlet 54a connected between the sealing surface WL0 in the drain trap pipeline 12 and the water reservoir opening / closing valve 50, and its outlet 54b connected to the drain flow path 14b downstream of the water reservoir opening / closing valve 50 in the drain socket 14. The outlet 54b of the air vent pipe 54 may be connected to a drainage flow path such as the drain pipe 16 that is connected downstream of the drain socket 14. Furthermore, as shown in FIG. 7, the outlet 54b of the air vent pipe 54 is positioned adjacent to the rear of the water reservoir valve in the closed state so that it is closed by cleaning water passing through the water reservoir valve in the open state.

[0028] Next, as shown in FIG. 7, the inlet 54a of the air vent pipe 54 is connected to the overflow flow path 40a by being positioned above the outlet 40b of the overflow pipe 40 (overflow flow path 40a) which communicates with the descending pipe 12f of the lower drain trap pipe 12. The air vent pipe 54 curves upward from its inlet 54a toward its top portion 54c, then curves downward from the top portion 54c, and extends linearly to its outlet 54b below. Furthermore, the inlet 54 a and the top 54 c of the air vent pipe 54 are positioned higher than the top 12 g of the drain trap pipe 12 . As shown in Figures 3 and 7, the air vent pipe 54 is provided with a check valve 56. The check valve 56 allows air A0 to pass from the inlet 54a side of the air vent pipe 54 toward the outlet 54b side, while blocking the flow of air A0 from the outlet 54b side of the air vent pipe 54 toward the inlet 54a side.

[0029] Next, with reference to Figures 8A to 8C, we will explain the emergency response operations carried out when performing toilet flushing in an emergency such as a power outage in a flush toilet 1 according to the first embodiment of the invention, as well as the series of movements and actions related to the flush toilet 1 that accompany these emergency response operations. 8A to 8C are schematic diagrams showing the flush toilet of this embodiment in an emergency state before water is filled, when water is filled, and when flushing, respectively. First, as shown in FIG. 8A, in the event of an emergency such as a power outage, the operating portion 52 of the water reservoir opening / closing valve 50 is operated before starting a toilet flush, to previously close the water reservoir opening / closing valve 50. Then, when flushing water is supplied to the bowl portion 10 of the toilet body 2 from outside using a pail or bucket, or when overflow flushing water W2 is supplied from the water storage tank 30 to the descending pipe 12f of the drain trap pipe 12 via the overflow flow path 40a, air A0 is quickly vented by the air vent pipe 54 into the area A1 between the sealing surface WL0 and the water storage opening / closing valve 50 in the drain trap pipe 12. As a result, before emergency toilet flushing begins, the area A1 upstream of the water storage opening / closing valve 50 in the drain trap pipe 12 is filled with flushing water, and water is stored in both the bowl portion 10 of the toilet body 2 and the drain trap pipe 12. Then, after confirming that the level of the flushing water in the bowl portion 10 of the toilet body 2 has risen to the required water level WL3 required for emergency toilet flushing, as shown in Figure 8B, the operating portion 52 of the water storage opening / closing valve 50 is operated to open the water storage opening / closing valve 50 and start emergency toilet flushing, as shown in Figure 8C. At this time, as shown in Figure 8C, flush water W3 in the drain trap pipe 12 is discharged into the drain flow path 14b downstream of the water storage opening / closing valve 50. At the same time, flush water W3 containing waste in the bowl portion 10 of the toilet body 2 is sucked into the drain trap pipe 12 by the siphon action occurring in the drain trap pipe 12, and then discharged from the outlet portion 12d of the drain trap pipe 12 through the internal flow path 14b of the drain socket 14 into the drain pipe 16, completing the emergency toilet flush.

[0030] Next, the operation of the flush toilet 1 according to the first embodiment of the present invention described above will be explained with reference to Figs. 1 to 8C. First, with the flush toilet 1 according to the first embodiment of the present invention, the water reservoir opening / closing valve 50 is normally kept in an open state when a toilet flush is performed. On the other hand, when flushing a toilet in an emergency such as a power outage or a breakdown in the pump 32 of the flush water supply device 4, the operating unit 52 is operated before starting the toilet flush to close the water reservoir opening / closing valve 50 in advance (see Figure 8A). At this time, when the water storage opening / closing valve 50 is closed in advance, flushing water is supplied into the bowl portion 10 of the toilet body 2, or overflow flushing water W2 is supplied from the water storage tank 30 into the descending pipe 12f of the drain trap pipe 12 via the overflow flow path 40a, and air A0 is quickly vented into the area A1 between the sealing surface WL0 and the water storage opening / closing valve 50 in the drain trap pipe 12 by the air vent pipe 54 (see Figures 7 and 8A). This ensures that air pockets are prevented from forming in the area A1 upstream of the water reservoir on-off valve 50 in the drain trap pipe 12, and that the area can be quickly filled with flush water before emergency toilet flushing begins (see FIG. 8B). Therefore, a larger amount of flush water can be secured to accumulate in the area A1 upstream of the water reservoir on-off valve 50 in the drain trap pipe 12. Therefore, it is also possible to prevent an increase in the required water level WL3 (see FIG. 8B) of flush water within the bowl portion 10 of the toilet body 2 that is required for toilet flushing in an emergency. This makes it possible to prevent flush water in bowl portion 10 of toilet body 2 from leaking to the outside in an emergency (so-called "outside the machine leakage"). Also, when starting a toilet flush in an emergency, it is possible to prevent the user from becoming anxious and opening water reservoir opening / closing valve 50 too early while the flush water level rising in bowl portion 10 of toilet body 2 is rising to required water level WL3, resulting in an insufficient toilet flush. As a result, when flushing the toilet in an emergency such as a power outage, air pockets downstream of the water sealing surface WL0 in the drain trap pipe 12 of the toilet body 2 are suppressed and filled with flushing water, thereby preventing the required water level WL3 of flushing water in the bowl portion 10 of the toilet body 2 from increasing and preventing water leakage outside the machine, thereby ensuring that the toilet is flushed.

[0031] Furthermore, according to the flush toilet 1 of this embodiment, the inlet 54a of the air vent pipe 54 is connected between the water sealing surface WL0 and the water sump opening / closing valve 50 in the drain trap pipeline 12, while the outlet 54b of the air vent pipe 54 is connected to the drainage flow path 14b downstream of the water sump opening / closing valve 50, so that odorous air A0 in the area A1 between the water sealing surface WL0 and the water sump opening / closing valve 50 in the drain trap pipeline 12 can be reliably discharged from the inlet 54a to the outlet 54b of the air vent pipe 54 and into the drain pipe 16 downstream (rear) of the drainage flow path 14b. Therefore, it is possible to reliably prevent odor-containing air A0 in the area A1 between the sealing surface WL0 and the water storage opening / closing valve 50 in the drain trap pipe 12 from flowing back into the area A1 upstream of the water storage opening / closing valve 50 in the drain trap pipe 12 or into the bowl portion 10 of the toilet body 2.

[0032] Furthermore, in the flush toilet 1 of this embodiment, the inlet 54a of the air vent pipe 54 is connected between the sealing surface WL0 in the drain trap pipe line 12 and the water reservoir opening / closing valve 50, while the outlet 54b of the air vent pipe 54 is connected to the drainage flow path 14b downstream of the water reservoir opening / closing valve 50 in the drain socket 14 assembled to a part of the toilet body 2. This allows odorous air A0 in the area A1 between the sealing surface WL0 and the water storage opening / closing valve 50 in the drain trap pipeline 12 to be reliably discharged from the inlet 54a to the outlet 54b of the air vent pipe 54 into the drain flow path 14b of the drain socket 14. Furthermore, since the outlet 54b of the air vent pipe 54 is connected to the drainage flow path 14b of the drain socket 14, the air vent pipe 54 can be easily attached within the area of ​​the toilet body 2, eliminating the need for additional work on the external drainage pipe 16 located behind the wall W on which the toilet body 2 is installed or below the floor surface F, for example.

[0033] Furthermore, in the flush toilet 1 of this embodiment, the outlet 54b of the air vent pipe 54 is positioned adjacent to the rear of the closed water reservoir valve 50, so that when the closed water reservoir valve 50 is opened to initiate toilet flushing in an emergency such as a power outage, the flush water W3 passing through the water reservoir valve 50 can close the outlet 54b of the air vent pipe 54 (see Figure 8C). Furthermore, because the outlet 54b of the air vent pipe 54 is filled with flushing water W3 that passes through the water reservoir opening / closing valve 50, the air vent pipe 54 does not suck in air A0 from its outlet 54b, and therefore air A0 is not discharged from the inlet 54a of the air vent pipe 54. This prevents air A0 from being entrained in the flushing water W3 used to flush the toilet, preventing a decrease in flushing performance. Therefore, in this embodiment, a form is described in which the toilet is flushed using only rim water spouting from the rim outlet 18a, that is, so-called "toilet flushing using 100% rim water spouting", but if a so-called "siphon type flush toilet" is used in which the siphon action is used to suck up waste within the bowl portion 10 of the toilet body 2 and then discharged all at once to the outside through the drain trap, it is possible to prevent the flush water W3 passing through the open water storage opening / closing valve 50 during normal flushing from sucking in the air A0 flowing out from the inlet 54a of the air vent pipe 54, making it difficult to maintain the siphon action. Furthermore, even in the event of an emergency such as a power outage, even if a siphoning effect occurs when the water storage valve 50 is closed to store water in the drain trap pipeline 12 and then the water storage valve 50 is opened, the cleaning water W3 passing through the open water storage valve 50 closes the outlet 54b of the air vent pipe 54, and air A0 is no longer sucked in from the outlet 54b of the air vent pipe 54, thereby preventing the siphoning effect from becoming difficult to sustain.

[0034] Furthermore, according to the flush toilet 1 of this embodiment, the outlet 40b of the overflow flow path 40a, which allows flush water W2 that has exceeded the specified water level (upper limit water level, full water level) WL1 in the storage tank 30 of the flush water supply device 4 to overflow, is connected to the descending pipe 12f between the sealing surface WL0 of the drain trap pipe 12 and the water storage opening / closing valve 50, so that the overflow port 30b and the opening cross-sectional area S1 of the outlet 40b of the overflow flow path 40a can be connected to the drain trap pipe 12 with a relatively large setting. Therefore, before emergency toilet flushing begins, the overflow flush water W2 flowing out from the outlet 40b of the overflow flow path 40a can be quickly stored in the area A1 between the sealing surface WL0 in the drain trap pipe 12 and the water storage opening / closing valve 50 (see Figure 8B).

[0035] Furthermore, with the flush toilet 1 of this embodiment, the inlet 54a of the air vent pipe 54 is connected to the overflow flow path 40a, so the air A0 within the overflow flow path 40a can also be easily vented by the air vent pipe 54. This improves the overflow performance in the overflow flow path 40a, and also enables the overflow flushing water W2 flowing out from the outlet 40b of the overflow flow path 40a to be quickly stored in the area A1 between the sealing surface WL0 in the drain trap pipe 12 and the water storage opening / closing valve 50 before emergency toilet flushing begins. Incidentally, when collecting water in the drain trap pipe 12 during an emergency such as a power outage, if the overflow flow path 40a is not provided at the top of the drain trap pipe 12, it is necessary to connect the inlets of at least two air vent pipes to the top of the drain trap pipe 12 and the overflow flow path 40a, etc., but the need for multiple air vent pipes will complicate the structure and increase manufacturing costs. On the other hand, in this embodiment, the overflow flow path 40a is provided at the top of the drain trap pipe line 12, and the inlet 54a of the air vent pipe 54 is connected to the top of the drain trap pipe line 12 and the top of the overflow flow path 40a, so that the air vent pipe 54 can be of a single form, thereby simplifying the structure and reducing manufacturing costs.

[0036] Furthermore, in the flush toilet 1 of this embodiment, the air vent pipe 54 is equipped with a check valve 56, which allows the flow of air A0 from the inlet 54a side toward the outlet 54b side of the air vent pipe 54 to pass, while preventing the flow of air A0 from the outlet 54b side toward the inlet 54a side of the air vent pipe 54 (reverse flow of air A0). Therefore, the air flow in the air vent pipe 54A0 can be restricted to one direction to prevent backflow, thereby eliminating air accumulation in the area A1 between the sealing surface WL0 and the water storage opening / closing valve 50 in the drain trap pipe 12 before emergency toilet flushing is started, and ensuring a larger amount of flush water to accumulate in the area A1 upstream of the water storage opening / closing valve 50. In addition, during normal flushing, it is possible to prevent the flush water W3 passing through the open water reservoir valve 50 from sucking in the air A0 flowing out from the inlet 54a of the air vent pipe 54, which makes it difficult to maintain the siphon action.

[0037] Next, a flush toilet 100 according to a second embodiment of the present invention will be explained with reference to Figures 9A and 9B. 9A and 9B are enlarged cross-sectional views of the outlet and downstream portion of the drain trap pipe of a flush toilet according to a second embodiment of the present invention, showing the state in which the water reservoir opening / closing valve is open and the state in which the water reservoir opening / closing valve is closed. The closed valve state is shown. Here, in the flush toilet 100 according to the second embodiment of the present invention shown in Figures 9A and 9B, the same parts as the flush toilet 1 according to the first embodiment of the present invention described above are given the same reference numerals, and explanations of these will be omitted. As shown in Figures 9A and 9B, in the flush toilet 100 of this embodiment, the inlet 154a of the air vent pipe 154 is connected to the uppermost part 112a of the drain trap pipe 112, which differs from the structure in the flush toilet 1 of the first embodiment of the present invention described above, in that the inlet 54a of the air vent pipe 54 is connected to the overflow flow path 40a. Furthermore, in this embodiment, the structure in which the air vent valve 156, which opens and closes the outlet 154b of the air vent pipe 154, is integral with the water reservoir valve 150 differs from the structure of the water reservoir valve 50 in the flush toilet 1 of the first embodiment of the present invention described above. Furthermore, this air vent opening / closing valve 156 is adapted to rotate about the same rotation axis as the rotation axis 150 a of the water reservoir opening / closing valve 150 , and is adapted to rotate in conjunction with the water reservoir opening / closing valve 150 . That is, as shown in FIG. 9A, when the water reservoir opening / closing valve 150 opens the outlet 112b of the drain trap pipe 112, the air vent opening / closing valve 156 is configured to close the outlet 154b of the air vent pipe 154 adjacent to the pivot shaft 150a of the water reservoir opening / closing valve 150. On the other hand, as shown in FIG. 9B, when the water reservoir on-off valve 150 closes the outlet portion 112b of the drain trap pipe 112, the air vent valve 156 is configured to open the outlet 154b of the air vent pipe 154.

[0038] According to the flush toilet 100 according to the second embodiment of the present invention described above, the air vent on-off valve 156, which is provided integrally with the water reservoir on-off valve 150 and opens and closes the outlet 154b of the air vent pipe 154, can be linked to the water reservoir on-off valve 150. Furthermore, when the water reservoir opening / closing valve 150 is open, this air vent opening / closing valve 156 closes the outlet of the air vent pipe (see FIG. 9A), and in the case of this embodiment which employs a so-called "siphon type flush toilet", this prevents the flush water W3 passing through the open water reservoir opening / closing valve 150 during normal flushing from drawing in air A0 flowing out from the inlet 154a of the air vent pipe 154, making it difficult to maintain the siphon action. On the other hand, when the water reservoir opening / closing valve 150 is closed, the air vent valve 156 keeps the outlet 154b of the air vent pipe 154 open (see Figure 9B), so that even if air accumulates in the area A101 between the water sealing surface WL0 and the water reservoir opening / closing valve 150 in the drain trap pipeline 112, air can be quickly vented through the air vent pipe 154.

[0039] In the flush toilet 1,100 according to the first and second embodiments of the present invention described above, a "floor-mounted flush toilet" configuration is adopted in which the toilet body 2 is placed in contact with the floor surface F, and the drainage configuration has been described as an example in which a so-called "wall drainage" drainage configuration is adopted in which the outlet portion 12d of the drain trap pipe 12 is connected to the drain pipe 16 on the back side of the wall W (or the front wall W of the cabinet C) via the drain socket 14. However, when a "floor-mounted flush toilet" is adopted, the drainage form is not limited to "wall drainage", and a so-called "floor drainage" drainage form may also be adopted in which the outlet portion 12d of the drain trap pipe 12 is connected to a drain pipe located below the floor surface F via the drain socket 14. In addition, instead of adopting a "floor-mounted flush toilet" configuration, a so-called "wall-hung flush toilet" may be adopted in which the rear of the toilet body 2 is fixed to the wall W of the toilet room T (or the front wall W of the cabinet C) and positioned above and spaced apart from the floor surface F. Furthermore, in the flush toilet 1,100 of the first and second embodiments of the present invention described above, a form has been described in which so-called "toilet flushing with 100% rim water spouting" is performed using only rim water spouting from only the rim water spout 18a, but as a modified example, it is also possible to apply a form in which so-called "toilet flushing with rim jet flushing" is performed using a combination of rim water spout W1 from the rim water spout 18a of the toilet body 2 and jet water spouting from the jet water spout. Furthermore, as a modified example of the flush toilet 1,100 of the first and second embodiments of the present invention described above, it is also applicable to a so-called "hybrid flush toilet" in which flush water supplied under direct pressure from the water supply is supplied directly to the rim spout 18a of the toilet body 2, and flush water that is temporarily supplied and stored in the water storage tank 30 is supplied to the jet spout of the toilet body 2 by the pump 32. [Explanation of symbols]

[0040] 1. Flush toilet according to the first embodiment of the present invention 2 Toilet bowl body 4. Cleaning water supply device 6 Waste receiving surface 8 Rim 10 Bowl section 12 Drain trap line 12a Inlet of drain trap pipe 12b Bottom end of drain trap pipe 12c Top of drain trap line 12d Outlet of drain trap pipe 12e Drain trap pipe connection parts 12f Drain trap pipe descending pipe 12g Top of drain trap pipe 14 Drain socket 14a Drain socket body 14b Drain socket internal flow passage, drain flow passage 14c Inlet of the internal flow passage of the drain socket 16 Drain pipe 16a Drain pipe inlet 18 Rim outlet 18a Rim Spout 22 Water supply source 24 Stopcock 26 Valve unit 28 Water supply section 28a Water supply pipe 28b Water supply nozzle 28c water inlet 28d Water receiving housing 28e Communication path 28f aperture 28g Bottom of opening 30 Water Tank 30a 1st outlet 30b Second outlet, overflow port 32 Pump 36 Rim side supply pipe 36a Rim Waterway 40 Overflow pipe 40a Overflow channel 40b Outlet of overflow channel 42 Float switch 44 Toilet body side connection pipe 44a Toilet body side connection pipe 46 Overflow side connecting pipe 46a Overflow side connection pipe 48 Flapper valve 50 Water reservoir on-off valve 50a Rotating shaft 50b Valve body 50c Mechanism 52 Operation section 54 Air vent pipe 54a Air vent pipe inlet 54b Air vent outlet 54c Top of the air vent pipe 56 Check valve 100 Flush toilet according to the second embodiment of the present invention 112 Drain trap pipe 112a Top of drain trap pipe 112b Outlet of drain trap pipe 150 Water reservoir on-off valve 150a Rotating shaft 154 Air vent pipe 154a Air vent pipe inlet 154b Air vent outlet 156 Air vent valve A0 Air in the area between the sealing surface and the water reservoir valve in the drain trap pipe A1 The area between the sealing surface and the water reservoir valve in the drain trap pipe C Cabinet F Floor R1 Rotation direction R2 Rotation direction T Toilet room S1 Overflow opening cross-sectional area W Toilet room wall or cabinet front wall W0 Water supply W1 Rim water discharge, rim cleaning water W2 Overflow cleaning water W3 Wash water passing through the water reservoir on-off valve WL0 Sealing surface of the bowl of the toilet body and the drain trap pipe WL1 Standard water level, upper limit water level, full water level in water tank WL2 Stop water level in water tank WL3 Required flush water level for emergency toilet flushing

Claims

1. A flush toilet that is flushed with flush water to expel waste, A toilet body including a bowl portion for receiving waste and a drain trap pipe forming a drain flow path for discharging the waste in the bowl portion; a water reservoir opening / closing valve that opens, closes, and closes the drain trap pipe to allow water to accumulate in the bowl portion; The drain trap pipe includes an inlet portion connected below the bowl portion, a curved pipe extending from the inlet portion to a rearward and downward lower end portion, and then rising to a rearward and upward top portion, and a descending pipe descending from the top of the curved pipe toward a rearward and downward outlet portion, and forms a water sealing surface in an area upstream of the top portion. A flush toilet characterized in that the water reservoir opening / closing valve is provided downstream of the water sealing surface of the drain trap pipe, and an air vent pipe is connected between the water sealing surface and the water reservoir opening / closing valve in the drain trap pipe, allowing air within that area to be vented to the outside.

2. 2. The flush toilet according to claim 1, wherein the air vent pipe has an inlet connected between the sealing surface in the drain trap pipe and the water reservoir opening / closing valve, and an outlet connected to the drainage flow path downstream of the water reservoir opening / closing valve.

3. A flush toilet as described in claim 1, further comprising a drain socket connected to the outlet of the drain trap pipe, the drain socket forming a drain flow path downstream of the water reservoir opening / closing valve and assembled to a part of the toilet body, the air vent pipe having an inlet connected between the sealing surface in the drain trap pipe and the water reservoir opening / closing valve and an outlet connected to the drain flow path of the drain socket.

4. 2. The flush toilet according to claim 1, wherein the outlet of the air vent pipe is disposed adjacent to the water reservoir opening / closing valve when in a closed state.

5. The toilet further comprises a flush water supply device that is provided with a water storage tank for storing flush water and supplies flush water to the toilet body, and an overflow flow path that causes flush water that has exceeded the specified water level in the water storage tank to overflow, The outlet of the overflow passage is connected between the sealing surface of the drain trap pipe and the water reservoir opening / closing valve, 2. The flush toilet according to claim 1, wherein the air vent pipe has an inlet or a top portion disposed at a position higher than the top portion of the drain trap pipe.

6. 6. The flush toilet according to claim 5, wherein the air vent pipe has an inlet connected to the overflow flow path.

7. A flush toilet as claimed in any one of claims 1 to 6, further comprising an air vent on-off valve that is provided integrally with the water reservoir on-off valve and opens and closes the outlet of the air vent pipe, and this air vent on-off valve is linked to the water reservoir on-off valve so that when the water reservoir on-off valve is open, the outlet of the air vent pipe is closed, and when the water reservoir on-off valve is closed, the outlet of the air vent pipe is open.

8. 7. The flush toilet according to any one of claims 1 to 6, wherein the air vent pipe is equipped with a check valve, and this check valve is configured to allow air to pass from the inlet side to the outlet side of the air vent pipe, while blocking air from flowing from the outlet side to the inlet side of the air vent pipe.

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