Flush toilet system using combination of domestic wastewater and tap water

Abstract

The present invention addresses the problem of maintaining a clean state and saving water in a flush toilet by reusing domestic wastewater that is generated in a living environment and by using clean tap water for a water seal in a wastewater trap pipeline. A flush toilet system (100) is provided with: a domestic wastewater tank (110); a tap water tank (120); a lavatory-pan bowl part (140); a wastewater trap pipeline (150) that forms a water seal between an ascending pipeline and a descending pipeline; and a toilet cleaning control unit (130) that is provided with a toilet cleaning mode and a water seal formation mode. The toilet cleaning control unit (130): in the toilet cleaning mode, supplies bowl cleaning water from the domestic wastewater tank (110) to the lavatory-pan bowl part (140) to clean the lavatory-pan bowl part; in the water seal formation mode, the water seal is formed with the tap water by supplying water seal formation water from the tap water tank (120) to the lavatory-pan bowl part (140) or to the wastewater trap pipeline (150). It is also possible to spray, on a wall surface in the vicinity of the water-seal water line, a spray water to clean the wall surface in a focused manner by using a water-seal water line spray nozzle (170).

Description

A flush toilet system that uses a combination of domestic wastewater and tap water

[0001] The present invention relates to a flush toilet system that temporarily receives waste and discharges it together with flush water. In particular, the present invention relates to a flush toilet system that uses tap water in combination with domestic wastewater generated from kitchens, showers, baths, etc. in residential and office spaces.

[0002] Water resources are important resources, but they are ubiquitous around the world. In the future, securing and utilizing water resources will become an important issue in national strategies. Water resources are beginning to be recognized as an important strategic material, as they are directly linked to improving people's lives, securing food and drinking water, and promoting domestic industries that consume water.

[0003] Various approaches have been taken to the issue of how to conserve and effectively utilize precious water resources, even in the case of flush toilets. Conventional flush toilet systems are equipped with a drain trap pipe. The drain trap pipe seals the connection between the flush toilet system and the sewerage system with accumulated water, and the seal water remains in the drain trap pipe from the time of flushing using the flush toilet system until the next time the flush toilet system is used, thereby blocking odors from the sewerage system and keeping it clean.

[0004] A conventional flush toilet basically comprises a toilet bowl having a waste receiving surface for temporarily receiving waste, a flush water supply means such as a water storage tank for supplying flush water to the toilet bowl, an inlet connected to the bottom of the toilet bowl, an ascending pipe extending upward from the inlet, and a descending pipe extending downward from the end of the ascending pipe. The flush toilet also includes a drain trap pipe that stores water from the inlet to at least a portion of the ascending pipe when not in use, forming a seal with at least a portion of the stored water. Patent Document 1 also includes a stored water utilization mechanism to improve water conservation. The flush toilet disclosed in JP 2012-215010 (Patent Document 1) reuses the seal water in the drain trap pipe to reduce the amount of wastewater used during flushing. Figure 5 shows the structure of the conventional flush toilet disclosed in JP 2012-215010 (Patent Document 1). As shown in Figure 5(a), the flush toilet of Patent Document 1 draws in a portion of the accumulated water (seal water) from the drain trap pipe as drawn-in water and stores it in a temporary tank 50d, and returns this drawn-in water to the drain trap pipe through return pipes 510d and 511d. In other words, the seal water is reused without being wasted, thereby saving water.

[0005] JP 2012-215010 A

[0006] Water resources are extremely important resources, and how to secure and utilize water resources is an important issue as a national strategy, but a large-scale water circulation system at the societal level is required.

[0007] The first problem with the technology of Patent Document 1 is that the water-saving effect is small and there is room for significant improvement. As mentioned above, the technology of Patent Document 1 is a water-saving technology that draws in and stores a portion of the seal water accumulated in the drain trap pipe, and then returns and drains it during flushing. However, the amount of water saved by this technology is small, being only a portion of the seal water accumulated in the drain trap pipe. On the other hand, a large amount of water is required to flush the bowl of a toilet. Therefore, in order to dramatically improve the water-saving effect, it is far more effective to save water during the flushing of the bowl of a toilet than to draw in and reuse the seal water from the drain trap pipe.

[0008] The second problem with the technology described in Patent Document 1 is the issue of contamination. In the technology described in Patent Document 1, when the toilet bowl temporarily receives waste and then discharges it together with flush water, the water intake mechanism first drives the intake means to draw in the accumulated water and store it in a temporary storage tank as intake water. Near the end of the flush, the return means is driven to return the intake water to the drain trap pipe. However, even if the intake means is driven to draw in seal water from the drain trap pipe before flushing the toilet bowl, the seal water accumulated in the drain trap pipe at the time of drawing in may already be contaminated by waste. If seal water accumulated in the drain trap pipe, which has been contaminated by waste, is drawn in and reused, the returned water may be contaminated with waste, and the resulting seal water itself may be contaminated. In other words, drawing and reusing seal water accumulated in the drain trap pipe solely for the purpose of water conservation not only has little water-saving effect, but also has the disadvantage of the resulting seal water being contaminated.

[0009] Inventor Masaaki Takano recognized the importance of water resources early on and has been developing technologies related to the utilization of water resources. For example, he has developed a groundbreaking water-saving faucet for kitchen sinks that reduces water consumption while improving cleaning power, a water-saving shower for bathrooms, and kitchenware such as dishes that have excellent stain-resistant properties and reduce water consumption during cleaning. In this work, inventor Masaaki Takano aimed to reduce water consumption in flush toilet systems by reusing domestic wastewater generated from kitchen, shower, and bath drainage while keeping the sealing water stored in the drain trap pipes clean by using clean water, thereby increasing water conservation effects.

[0010] In order to achieve the above-mentioned object of the present invention, the flush toilet system of the present invention is a toilet flushing system that uses a combination of domestic wastewater, including kitchen wastewater, shower wastewater, and bath wastewater generated from human living environments including residential environments, office environments, and commercial facilities, and tap water, and is equipped with a domestic wastewater tank that receives and stores the domestic wastewater, a tap water tank that receives and stores tap water from a tap water facility, a toilet bowl portion having a wastewater receiving surface for temporarily receiving waste, a drain trap pipe that has an inlet connected to the below of the toilet bowl portion, an ascending pipe, and a descending pipe, and that forms a water seal in the ascending pipe and the descending pipe when not in use, and a toilet flush control unit that has a toilet flush mode that flushes the toilet bowl portion and a subsequent water seal formation mode that stores water seal in the drain trap pipe, and is characterized in that the toilet flush control unit supplies bowl flush water from the domestic wastewater tank to the toilet bowl portion in the toilet flush mode, and supplies water seal formation water from the tap water tank to the toilet bowl portion or the drain trap pipe in the water seal formation mode.

[0011] With the above configuration, the bowl flush water used to flush waste from the toilet bowl is replaced by tap water, using domestic wastewater from the domestic wastewater tank, thereby reducing the amount of tap water used and saving water, while at the same time using tap water to store seal water in the drain trap pipe, maintaining a clean seal and a good toilet environment. In this way, water conservation and cleanliness are both achieved.

[0012] Next, in the configuration of the flush toilet system of the present invention, the toilet flushing control unit is configured to include a domestic wastewater tank water volume detection unit that detects whether the amount of domestic wastewater stored in the domestic wastewater tank is the amount of water required to flush the toilet bowl in the toilet flushing mode, and if the domestic wastewater tank water volume detection unit detects that there is not enough water to use in the toilet flushing mode, the toilet flushing control unit supplies tap water from the tap water tank to the toilet bowl in the toilet flushing mode, allowing it to be used as the bowl flushing water instead.

[0013] While the water supply tank is connected to the water supply system and receives water from the water supply, the domestic wastewater tank receives and stores wastewater from the human living environment, including kitchen, shower, and bath wastewater, and so temporary water shortages can be anticipated. Therefore, if the water storage volume in the domestic wastewater tank is detected to be insufficient for use in toilet flushing mode, the shortage can be compensated for by switching to a water supply from the water supply tank.

[0014] Next, in the configuration of the flush toilet system of the present invention, it is possible to configure it with a water seal draft jet nozzle that shoots out a jet of water onto the wall surface near the water seal draft. It is preferable that the jet angle of this water seal draft jet nozzle is adjusted to an angle that jets water toward the wall surface near the water seal draft.

[0015] With the above configuration, water is sprayed from the water seal line jet nozzle onto the wall near the waterline of the seal. Even if a flush toilet system flushes waste and uses clean tap water for the seal with each use, small amounts of fecal matter adhering to the walls of the toilet bowl and the drain trap pipe can accumulate over time. It is empirically expected that as the interval between toilet cleanings increases, a line of dirt will form along the waterline on the wall near the waterline of the seal. Furthermore, while the water seal formation water used in the water seal formation mode is tap water from the water tank, the bowl flush water used in the toilet flush mode is domestic wastewater, and even a small amount of oil may be mixed in, which can easily float and accumulate on the waterline. Therefore, the above-described configuration of the flush toilet system of the present invention includes a water seal line jet nozzle, which can spray water onto the wall near the waterline of the seal for special cleaning.

[0016] The above-mentioned water seal draft jet nozzle may be configured to be incorporated into the toilet seat body. In this configuration, the jet angle of the water from the water seal draft jet nozzle is set at a downward angle, toward the vicinity of the water seal draft. If the water is jetted from above downward, it is less likely to bounce back above the toilet bowl. Note that toilet seats with a warm water washing function, i.e., toilet seats equipped with a mechanism that jets warm water upward from a nozzle aimed at the user's buttocks, are now common, but the water seal draft jet nozzle of the present invention is similarly incorporated into the toilet seat body, and jets from above downward instead.

[0017] Here, it is also preferable that the user can operate the seal water line jet nozzle by pressing a button. In other words, if the operation button for the seal water line jet nozzle is provided on the toilet operation panel, the user can use it at any time by pressing the operation button for the seal water line jet nozzle on the toilet operation panel. In other words, the user can clean the wall surface near the seal water line at any timing before, during, or after using the flush toilet system. However, it is also possible to automate the jet operation of the seal water line jet nozzle. For example, this can be done between the toilet flush mode and the seal water formation mode.

[0018] Next, the water sprayed by the water seal line spray nozzle can be tap water or detergent-containing water, which is tap water with detergent added. In other words, the timing when the water seal line spray nozzle sprays the water is assumed to be just before or after the toilet flush mode ends, so if the water is tap water, the sprayed water can be used to form the seal water. If the water is detergent-containing water, the formed seal water contains detergent, but it can be said that containing detergent in the seal water itself is preferable in terms of maintaining cleanliness. If it foams during urination, it can also be expected to have a noise-deadening effect.

[0019] According to the flush toilet system of the present invention, the bowl flush water used to flush waste from the toilet bowl is provided by using domestic wastewater from the domestic wastewater tank instead of tap water, thereby eliminating the use of tap water and saving water, and by using tap water for the seal water formation water that stores seal water in the drain trap pipe, the seal water can be kept clean and a good toilet environment can be maintained, achieving both water conservation and maintaining cleanliness. Also, according to the flush toilet system of the present invention, the water is sprayed from the seal waterline jet nozzle onto the wall near the seal waterline, so that even if a small amount of bowl flush water used in the toilet flush mode is mixed in, it can be sprayed from the seal waterline jet nozzle onto the wall near the seal waterline.

[0020] Fig. 1 is a diagram showing an example of the configuration of a flush toilet system 100 according to Example 1 of the present invention. Fig. 2 is a diagram briefly explaining the operation of the flush toilet system 100 according to Example 1. Fig. 3 is a diagram showing the flow of supplying tap water as toilet flush water instead of domestic wastewater when a shortage of the remaining amount of wastewater in the domestic wastewater tank 130 is detected. Fig. 4 is a diagram showing an example of the configuration of a flush toilet system 100a equipped with a water seal draft waterline injection nozzle 170 according to Example 2. Fig. 5 is a diagram showing an example of the configuration of a flush toilet system in the prior art disclosed in JP 2012-215010 A (Patent Document 2).

[0021] An example of a flush toilet system according to the present invention will be described below. However, it goes without saying that the scope of the present invention is not limited to the specific uses, shapes, numbers, etc. shown in the following examples.

[0022] The flush toilet system 100 of the present invention is a toilet flushing system that uses tap water in combination with domestic wastewater, including kitchen wastewater, shower wastewater, and bath wastewater generated in human living environments, including residential environments, office environments, and commercial facilities. The flush toilet system 100 of the present invention plays a part in a social infrastructure system that supports the circulation of water resources.

[0023] Figure 1 is a simplified diagram showing the structure of a flush toilet system 100 of the present invention. Parts are shown in longitudinal cross section, and parts are depicted as blocks in a block diagram. The diagram shows only the main parts of the flush toilet system 100, and small components are not shown.

[0024] As shown in Figure 1, the flush toilet system 100 of the present invention includes a domestic wastewater tank 110, a domestic wastewater tank water level detection unit 131, a water supply tank 120, a toilet flush control unit 130, a toilet bowl unit 140, a drain trap pipe 150, and a toilet seat main body 160. While a toilet seat typically includes a toilet seat cover and a toilet lid in addition to the toilet seat main body 160, the toilet seat cover and toilet lid are not shown here, and only the toilet seat main body 160 is simply illustrated. In recent years, flush toilet systems have been equipped with a variety of functions, such as a warm water flush function, a sound deadening function, and a deodorizing function, and these functions are often primarily installed in the toilet seat main body 160. While these functions are assumed to be installed in the toilet seat main body 160 here, illustrations and detailed explanations of these functions are omitted.

[0025] The toilet bowl 140 is a container having a waste receiving surface for receiving waste, and is the so-called main container of the toilet.

[0026] The drain trap pipe 150 is a member having an inlet 121, an ascending pipe 122, and a descending pipe 123, with the inlet 121 connected to the bottom of the toilet bowl portion 140 and the ascending pipe 122 and the descending pipe 123 continuing behind the inlet 121. When the flush toilet system 100 is not in use, a water seal is formed between the ascending pipe 122 and the descending pipe 123.

[0027] The domestic wastewater tank 110 is a tank that receives and stores domestic wastewater. The domestic wastewater source connected to the domestic wastewater tank 110 is connected to a drainage system that discharges wastewater from human living environments, such as residential and office spaces. For example, this drainage system is for domestic wastewater generated from kitchen, shower, and bath use. Kitchen wastewater, shower wastewater, and bath wastewater flow into and are stored in these drainage systems. The domestic wastewater stored in the domestic wastewater tank 110 is so-called greywater, containing dirt from washing vegetables and food and dishwashing in the case of kitchen wastewater, and dirt from washing body soap, shampoo, conditioner, and human rinsing in the case of shower and bath wastewater. While conventional technology would have directly disposed of such domestic wastewater in the sewer system, the flush toilet system 100 of the present invention reuses this domestic wastewater to flush the toilet bowl 140 of the flush toilet. By reusing domestic wastewater that would otherwise be discarded to flush the toilet bowl 140 of the flush toilet, significant water conservation can be achieved.

[0028] The water supply tank 120 is a tank that receives and stores tap water from a waterworks facility. The source of tap water connected to the water supply tank 120 may be a general public waterworks facility or a private waterworks facility. In conventional technology, tap water drawn from the waterworks facility and stored in the water supply tank was used to flush waste accumulated in the toilet bowl 140 of a flush toilet, to clean the walls of the toilet bowl 140, and to seal the drain trap pipe 150. In contrast, the flush toilet system 100 of the present invention uses tap water stored in the water supply tank 120 only to seal the drain trap pipe 150. This dramatically reduces the amount of tap water used in the water supply tank 120 from the waterworks facility, resulting in significant water-saving effects.

[0029] The toilet flush control unit 130 is a control unit that controls at least the flushing process of the toilet bowl unit 140 and the process of forming a water seal in the drain trap pipe 150. In recent years, flush toilet systems have been equipped with various functions, such as a warm water flushing function, a sound-deadening function, and a deodorizing function, and these functions may also be installed, and detailed explanations of these functions will be omitted here. The toilet flush control unit 130 is equipped with an operation button panel 131 to accept user operations, and instructions input by the user via the operation button panel 131 are given to the toilet flush control unit 130, enabling the use of the various functions of the flush toilet system 100.

[0030] The flush toilet system 100 of the present invention has a toilet flush mode for flushing the toilet bowl 140, and a water seal formation mode following the toilet flush mode for storing seal water in the drain trap pipe 150. In the toilet flush mode, the toilet flush control unit 130 supplies domestic wastewater from the domestic wastewater tank 110 to the toilet bowl 140 as bowl flush water to flush the toilet bowl 140. In the water seal formation mode, the toilet flush control unit 130 supplies tap water from the tap water tank 150 to the toilet bowl 140 or the drain trap pipe 150 as seal formation water to form a water seal in the drain trap pipe 150.

[0031] The domestic wastewater tank water level detection unit 131 has the function of detecting whether the amount of domestic wastewater stored in the domestic wastewater tank 110 is the amount of water necessary to flush the toilet bowl section 140 in the toilet flush mode. The domestic wastewater tank water level detection unit 131 outputs detection result data to the toilet flush control unit 130. The toilet flush control unit 130 changes operation in the toilet flush mode according to the detection result of the domestic wastewater tank water level detection unit 131. In the normal toilet flush mode, the toilet flush control unit 130 supplies domestic wastewater from the domestic wastewater tank 110 to the toilet bowl section 140 as bowl flush water to flush the toilet bowl section 140, as described above.

[0032] Here, when the toilet flush control unit 130 receives data from the domestic wastewater tank water level detection unit 131 indicating that there is not enough water for the toilet flush mode, the toilet flush control unit 130 switches from the domestic wastewater tank 110 to the tap water tank 150 as an emergency toilet flush mode, supplies tap water to the toilet bowl unit 140, and uses the tap water as bowl flush water instead. The configuration shown above is an overview of the flush toilet system 100 of the present invention according to Example 1.

[0033] Next, the flow of operation of the flush toilet system 100 of the present invention according to Example 1 will be briefly explained. Figure 2 is a diagram briefly explaining the operation of the flush toilet system 100 of the present invention according to Example 1. Figure 2(a) is a diagram showing the flow of supplying domestic wastewater as toilet flush water in the toilet flush mode. Figure 2(b) is a diagram showing the flow of supplying tap water as seal formation water in the seal formation mode.

[0034] (1) When a user relieves themselves, they instruct the toilet flushing control unit 130 to start the toilet flushing mode via the operation panel (step S1 in Figure 2(a)). The instruction to start the toilet flushing mode can be given by pressing the flush button or by activating the flush button without touching it. In recent years, however, there has been an increase in toilet flushing control units 130 that automatically activate the toilet flushing mode without the user having to instruct it to start.

[0035] (2) Upon receiving an instruction to start the toilet flush mode, the toilet flush control unit 130 supplies domestic wastewater from the domestic wastewater tank 110 to the toilet bowl portion 140 as bowl flush water to flush the toilet bowl portion 140 (FIG. 2(a) step S2). From the beginning to the end of this toilet flush mode, waste matter present in the toilet bowl portion 140 is washed away, and the wall surface of the toilet bowl portion 140 is cleaned.

[0036] (3) The toilet flush control unit 130 activates the water seal formation mode following the toilet flush mode (step S3 in FIG. 2(b)).

[0037] (4) Tap water is supplied from the tap water tank 150 to the toilet bowl 140 or the drain trap pipe 150 as seal water, forming a seal in the drain trap pipe 150 (step S4 in FIG. 2(b)). The flushing process is carried out according to the procedure from step S1 to step S4, and waste matter present in the toilet bowl 140 is thoroughly washed away, and finally, clean tap water is used to form a seal in the drain trap pipe 150. In this way, a clean state is maintained, and in the toilet flushing mode, grey water, which is domestic wastewater, is used, resulting in a significant water-saving effect.

[0038] Prior to step S2, if the domestic wastewater tank water level detection unit 131 detects that the amount of domestic wastewater stored in the domestic wastewater tank 110 is insufficient to flush the toilet bowl 140 in the toilet flush mode, the alternative step S2 is replaced by the following procedure. This alternative step S2 will now be explained. Figure 3 is a diagram showing the flow of supplying tap water as a substitute for domestic wastewater as toilet flush water in the toilet flush mode when an insufficient amount of wastewater is detected in the domestic wastewater tank 130.

[0039] (Alternative 2) If the domestic wastewater tank water level detection unit 131 detects that the remaining amount of wastewater in the domestic wastewater tank 130 is insufficient, it notifies the toilet flush control unit 130 (alternative step S2-1 in Figure 3). The toilet flush control unit 130 changes operation in toilet flush mode according to the detection result of the domestic wastewater tank water level detection unit 131, receives an instruction to start the toilet flush mode from the user (alternative step S2-2 in Figure 3), and as an emergency toilet flush mode, the toilet flush control unit 130 switches from the domestic wastewater tank 110 to the tap water tank 150, supplies tap water to the toilet bowl unit 140, and uses the tap water as bowl flush water instead (alternative step S2-3 in Figure 3).

[0040] As described above, by using the flush toilet system 100 of the present invention according to Example 1, in flush mode, domestic wastewater is supplied from the domestic wastewater tank 110 to the toilet bowl portion 140 as bowl flush water to flush the toilet bowl portion 140, thereby saving tap water usage. Also, in seal formation mode, tap water is supplied from the tap water tank 150 to the toilet bowl portion 140 or the drain trap pipe 150 as seal formation water, and clean tap water is used in the drain trap pipe 150 to form a seal. In other words, it is possible to achieve both tap water conservation and the formation of clean seal water.

[0041] In the flush toilet system 100a of the present invention according to Example 2, even when clean tap water is used, for example, when the interval between toilet cleanings is extended, it is expected that a line of dirt will form along the waterline on the wall of the drain trap pipe 150 near the seal waterline. Taking into consideration that the bowl flush water used in the toilet flush mode is domestic wastewater, the flush toilet system 100a according to Example 2 is equipped with a water seal draft line jet nozzle 170, which jets water onto the wall of the drain trap pipe 150 near the seal waterline for intensive cleaning. The amount of water jetted onto the wall of the drain trap pipe 150 near the seal waterline by the water seal draft line jet nozzle 170 may be the amount of water needed to replace the seal water in the drain trap pipe 150, but since the purpose of the jet is to prevent dirt from settling on the wall near the seal waterline, a short, small amount of water may also be sufficient.

[0042] The flush toilet system 100a of the present invention according to Example 2 is an example configuration that includes a seal water line jet nozzle 170 inside the toilet seat body 160a in addition to the configuration of the flush toilet system 100 of the present invention described in Example 1. The seal water line jet nozzle 170 jets water to clean the boundary between the seal water draft and the wall surface of the drain trap pipe 150 in order to prevent the adhesion and accumulation of dirt that forms in a circular ring shape.

[0043] 4 is a diagram showing an example of the configuration of a flush toilet system 100a of the present invention according to Example 2. In addition to the components of the flush toilet system 100 of Example 1, including the domestic wastewater tank 110, mains water tank 120, toilet flush control unit 130, domestic wastewater tank water level detection unit 131, toilet bowl 140, and drain trap pipe 150, this system is configured to include a seal water draft waterline spray nozzle 170 within the toilet seat body 160a. Of these components, the toilet bowl 140, drain trap pipe 150, toilet flush control unit 130, domestic wastewater tank 110, domestic wastewater tank water level detection unit 131, and mains water tank 120 may be the same as those of Example 1, and detailed description thereof will be omitted here.

[0044] As shown in FIG. 4(a), a water-sealing waterline jet nozzle 170 is incorporated into the toilet seat body 160a of the flush toilet system 100a of the present invention according to Example 2. FIG. 4(a) simply illustrates the state in which the water-sealing waterline jet nozzle 170 is housed within the toilet seat body 160a. The toilet seat is structured with a toilet seat cover and a toilet lid in addition to the toilet seat body 160a. However, the toilet seat cover and toilet lid are not shown here, and only the toilet seat body 160a is simply illustrated. The toilet seat body 160a is also equipped with various functions common to flush toilet systems, such as a warm water cleaning function, a sound-deadening function, and a deodorizing function, but these functions will not be illustrated or described in detail here. In FIG. 4, the warm water toilet seat shower function is simply illustrated as a warm water toilet seat shower nozzle 161. When washing the user's bottom, this warm water toilet seat shower nozzle 161 protrudes from the toilet seat body 160a and sprays a warm water shower upward.

[0045] 4(b) shows the state in which the seal water draft jet nozzle 170 protrudes from the toilet seat body 160a and jets water downward toward the wall surface near the seal water draft. The seal water draft jet nozzle 10 is arranged so that it can shoot the jet of water onto the wall surface near the seal water draft. The jet outlet of the seal water draft jet nozzle 170 is adjusted to an angle (downward) facing the wall surface of the drain trap pipe 150 near the seal water draft.

[0046] The structure of the nozzle of the seal water draft jet nozzle 170 is not limited, but may be, for example, a nozzle that sprays water in a circularly expanding cone shape. Because the boundary between the seal water draft surface and the wall surface of the drain trap pipe is a circular ring, the nozzle of the seal water draft jet nozzle 170 sprays water in a circularly expanding cone shape in order to intensively clean that area. Furthermore, the nozzle structure of the seal water draft jet nozzle 170 does not have to be one that sprays water in a circular shape, as long as it is a circular nozzle. For example, the nozzle of the seal water draft jet nozzle 170 may spray water in a string shape, with the destination of the jet moving circularly along the boundary between the seal water draft surface and the wall surface of the drain trap pipe. As shown in FIG. 4( b), the water from the seal water draft jet nozzle 170 is sprayed onto the wall surface of the drain trap pipe 150 near the seal water draft surface.

[0047] The spray angle of the water from the seal water draft jet nozzle 170 is set at a downward angle, toward the vicinity of the seal water draft surface. With this angle setting, even if the water is sprayed from the seal water draft jet nozzle 170 with a somewhat strong pressure, it is unlikely to bounce back above the toilet bowl section 140. Next, the timing of spraying the water from the seal water draft jet nozzle 170 will be explained. The timing of spraying the water from the seal water draft jet nozzle 170 is not limited, but may be as follows:

[0048] For example, a user operates the activation of the seal water draft line spray nozzle 170. If an operation button for the seal water draft line spray nozzle 170 is provided on the toilet operation panel, the user can press the button on the operation panel, at any time before, during, or after using the flush toilet system 100a, according to the user's request, and the toilet flush control unit 130 will start the cleaning process for the wall surface of the drain trap pipe 150 near the seal water draft line.

[0049] In addition, automatic operation is also possible, for example, by the toilet flushing control unit 130. For example, the toilet flushing control unit 130 is equipped with a timer and an automatic processing program, records the time of the most recent toilet flushing process, and when it detects that a predetermined time has passed since the time of the most recent toilet flushing process, the automatic processing program is activated and executes the spraying process of the seal water line spray nozzle 170.

[0050] Next, the type of water sprayed by the sealing water draft line spray nozzle 170 is not limited, but can be tap water alone or detergent-containing water, which is tap water with a detergent added. If the spray water is detergent-containing water, it is expected to be more effective in preventing the adhesion of grease and oil stains. By spraying water from the sealing water draft line spray nozzle 170 onto the wall of the drain trap pipe 150 near the sealing water draft, it is possible to intensively clean the area near the sealing water draft line, where dirt tends to accumulate, and to prevent the adhesion of grease and oil stains.

[0051] 100 Flush toilet system 110 Domestic wastewater tank 120 Tap water tank 130 Flush control unit 131 Domestic wastewater tank water level detection unit 140 Toilet bowl unit 150 Drain trap pipe 160 Toilet seat body 161 Hot water flush nozzle 170 Sealing water line spray nozzle

Claims

1. A toilet flushing system that uses tap water in combination with domestic wastewater, including any or a combination of kitchen wastewater, shower wastewater, bath wastewater, and laundry wastewater generated from human living environments including residential environments, office environments, and commercial facilities, and the system comprises: a domestic wastewater tank that receives and stores the domestic wastewater; a tap water tank that receives and stores tap water from the tap water facility; a toilet bowl portion having a wastewater receiving surface for temporarily receiving waste; a drain trap pipe that has an inlet, an ascending pipe, and a descending pipe connected to the bottom of the toilet bowl portion, and that forms a water seal in the ascending pipe and the descending pipe when not in use; and a toilet flushing control unit that has a toilet flush mode that flushes the toilet bowl portion and a subsequent water seal formation mode that stores water seal in the drain trap pipe, wherein the toilet flush control unit supplies bowl flush water from the domestic wastewater tank to the toilet bowl portion in the toilet flush mode, and supplies water seal formation water from the tap water tank to the toilet bowl portion or the drain trap pipe in the water seal formation mode.

2. The flush toilet system described in claim 1, characterized in that the toilet flushing control unit is equipped with a domestic wastewater tank water volume detection unit that detects whether the amount of domestic wastewater stored in the domestic wastewater tank is the amount of water required to flush the toilet bowl in the toilet flushing mode, and if the domestic wastewater tank water volume detection unit detects that there is not enough water in the toilet flushing mode, the toilet flushing control unit supplies tap water from the tap water tank to the toilet bowl in the toilet flushing mode and uses it as the bowl flushing water instead.

3. A toilet flushing system as described in claim 1 or 2, characterized in that it is provided with a seal water draft line injection nozzle that shoots out a jet of water onto a wall surface near the draft surface of the seal water, the seal water draft line injection nozzle is adjusted to an angle that injects the jet of water toward the wall surface near the draft surface of the seal water, and the jet of water is injected from the seal water draft line injection nozzle onto the wall surface near the draft surface of the seal water.

4. A flush toilet system as described in claim 3, characterized in that the seal water draft waterline spray nozzle is incorporated into the toilet seat body, and the spray angle of the water from the seal water draft waterline spray nozzle is set diagonally downward toward the waterline of the seal water, making it less likely to splash back above the toilet bowl.

5. A toilet flushing system as described in claim 3, wherein an operation button for the seal water draft jet nozzle is provided on the toilet operation panel, allowing the user to clean the wall surface near the seal water draft line at any time before, during, or after using the flush toilet system.

6. The toilet flushing system of claim 3, wherein the spraying process of the water by the water seal draft spray nozzle is automatically controlled by the toilet flushing control unit, and the water spraying process is automatically performed after a predetermined time has elapsed after the water seal formation mode following the most recent use of the toilet.

7. A toilet flushing system as described in claim 3, characterized in that the water sprayed by the seal water line spray nozzle is tap water or detergent-containing water obtained by adding detergent to the tap water.

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