Hidden toilet flushing valve

Abstract

The invention discloses a hidden closestool flushing valve, which belongs to the technical field of closestools, and comprises a water tank shell mounted at the bottom end in a closestool, the water tank shell is provided with a first flushing pipe connected with an upper ring of the closestool and a second flushing pipe connected with the bottom of the closestool, and the water tank shell is also provided with a water inlet pipe; a starting mechanism, a control piston and a flow channel switching mechanism are arranged in the water tank shell, the water inlet pipe is connected with the side wall of the control piston, when the starting mechanism is pressed, the control piston is driven to move back and forth, and when the control piston moves back and forth, the flow channel switching mechanism is controlled to be opened and closed. When the control piston moves back and forth, part of water flows into the water tank shell, a water drainage sleeve is arranged at the joint of the second flushing pipe and the flow channel switching mechanism, and when the second flushing pipe drains water, water in the water tank shell flows into the second flushing pipe from the water drainage sleeve under the action of negative pressure.

Description

Technical Field

[0001] This invention relates to the field of toilet technology, and more particularly to a concealed toilet flush valve. Background Technology

[0002] Chinese patent publication CN114411898A discloses a tankless mechanical valve flushing system, belonging to the field of toilet flushing systems. The system features a main control chamber with a first drain pipe, a second drain pipe, and a water inlet pipe on one side. A flow channel switching mechanism connects the first and second drain pipes. When the main control piston moves towards the activation chamber, the first drain pipe connects to the water inlet pipe. A water passage chamber is provided on the main control piston, and a switching control water channel is connected to the other end of the main control chamber. When the main control piston resets, the water passage chamber connects the switching control water channel to the water inlet pipe, driving the flow channel switching mechanism to connect the second drain pipe to the water inlet pipe. A delay setting in the activation chamber allows a single trigger to control the main control piston to complete one reciprocating motion. During this motion, the main control piston controls the flow channel switching mechanism to switch the water outlet pipe, thereby driving the water flow to complete the entire process of outer ring flushing, jet flushing, and outer ring secondary flushing and water storage. The entire process is completed through mechanical force and does not rely on the electricity of a water tank.

[0003] For aesthetic reasons, existing flush toilets generally have limited space at the top, making it more suitable to place the control mechanism in the lower cavity. However, for mechanical flushing mechanisms, the effects of water pressure and gravity need to be considered, and existing flushing mechanisms cannot meet the usage requirements. Summary of the Invention

[0004] To address the aforementioned problems, this invention aims to solve the problems described above. One object of this invention is to provide a concealed toilet flush valve that solves the problems described above.

[0005] The solution adopted in this invention is: a concealed toilet flush valve, including a water tank housing installed at the bottom of the toilet interior, the water tank housing being provided with a first flush pipe connected to the upper ring of the toilet and a second flush pipe connected to the bottom of the toilet, the water tank housing also being provided with a water inlet pipe; the concealed layout makes the toilet more aesthetically pleasing and can be directly adapted to most toilets on the market.

[0006] The water tank housing is equipped with an activation mechanism, a control piston, and a flow channel switching mechanism. The water inlet pipe is connected to the side wall of the control piston. When the activation mechanism is pressed, it drives the control piston to move back and forth. The back and forth movement of the control piston controls the opening and closing of the flow channel switching mechanism. When the flow channel switching mechanism is closed, the water flow from the inlet pipe passes through the control piston and is discharged from the first flushing pipe. When the flow channel switching mechanism is open, the water flow from the inlet pipe passes through the control piston and is discharged from the second flushing pipe. Based on pure mechanical control, it does not rely on electricity and is easy to use.

[0007] As the control piston moves back and forth, some water flows into the water tank housing. A drain sleeve is provided at the connection between the second flush pipe and the flow channel switching mechanism. When the second flush pipe drains, water in the water tank housing flows from the drain sleeve into the second flush pipe under negative pressure. This unique return water structure removes water from the water tank housing while preventing toilet backflow contamination.

[0008] Furthermore, one end of the drain sleeve is fixed to one outlet end of the flow channel switching mechanism, and a fixing ring is provided on the middle side wall of the drain sleeve. The fixing ring is fixedly connected to the water tank shell, and a water guide hole is provided in the middle of the fixing ring. The water guide hole is in communication with the inside of the water tank shell. The second flushing pipe is provided with a water pipe connector at its end. The water pipe connector is fixed to the water tank shell. A return cavity is provided between the water pipe connector and the fixing ring. The return cavity connects the inside of the water pipe connector and the water guide hole. A one-way sealing ring is provided in the return cavity. The one-way sealing ring is fixed to the end of the water guide hole, so that the water in the water guide hole can flow into the return cavity in one direction.

[0009] Furthermore, the drain sleeve is provided with a return groove, the one-way sealing ring is fixed in the return groove, the one-way sealing ring is provided with a fixing part and a deformation part, the thickness of the fixing part is greater than the thickness of the deformation part, the fixing part is sleeved on the return groove, and the deformation part extends from the fixing part until it covers the water guide hole.

[0010] A preferred technical solution is that the control piston includes a main piston and a secondary piston. The main piston is divided into a control chamber and a water flow chamber on both sides. The main piston is slidably connected in the control chamber. The starting mechanism is connected to the control chamber. When the starting mechanism is activated, the control chamber is connected to the inside of the water tank shell. Under water pressure, the main piston slides to discharge water from the control chamber to the water tank shell. The water inlet pipe is connected to the water flow chamber. The water flow chamber is provided with a water outlet port connected to the flow channel switching mechanism. When the main piston is reset, it squeezes the secondary piston against the water outlet port, cutting off the water channel between the water inlet pipe and the flow channel switching mechanism.

[0011] A preferred technical solution is that the main piston is provided with a mounting hole in the middle, a guide post and a compression spring are provided in the mounting hole, the compression spring is sleeved on the guide post, and the compression spring provides the main piston with a force to move towards the water outlet port; The main piston is provided with a water supply channel, which connects the mounting hole and the water flow chamber. When the main piston is reset, the water in the water flow chamber enters the control chamber after passing through the water supply channel and the mounting hole.

[0012] A preferred technical solution is that a secondary spring is sleeved on the secondary piston, one end of the secondary spring abuts against the water outlet port, the secondary spring provides a force to the secondary piston away from the water outlet port, and a secondary sealing ring is provided in the middle of the secondary piston, which abuts against the water outlet port when closed; A pressure regulating gap is provided between the auxiliary piston and the main piston. The main piston is provided with a limiting section, and the auxiliary piston is restricted to sliding only on the limiting section. A pressure regulating sealing ring is provided at the end of the limiting section. When the main piston is reset, the pressure regulating sealing ring abuts against the end of the auxiliary piston.

[0013] A preferred technical solution is that a flow-limiting plug is fixedly installed at the end of the first flushing pipe, a flow-limiting cap is slidably installed in the first flushing pipe, a flow-limiting column is installed in the middle of the flow-limiting plug, a flow-limiting spring is sleeved on the flow-limiting column, one end of the flow-limiting spring abuts against the flow-limiting cap, so that the flow-limiting cap has a tendency to move away from the flow-limiting plug; a flow-limiting hole is installed in the middle of the flow-limiting cap, and when the water pressure increases, the flow-limiting cap moves towards the flow-limiting column, and the gap between the flow-limiting column and the flow-limiting cap decreases; The flow-limiting cap has a return water pressure regulating channel on the side near the water inlet. The return water pressure regulating channel is connected to the inside of the water tank shell. A return water piston and a return water spring are installed in the return water pressure regulating channel. The return water spring abuts against the return water piston, causing the return water piston to close the return water pressure regulating channel. When a negative pressure is formed in the first flushing pipe, the return water piston squeezes the return water spring, and the return water pressure regulating channel opens.

[0014] The preferred technical solution is that the flow channel switching mechanism includes a switching housing, a switching piston and a switching spring, the switching housing is provided with a first flow channel and a second flow channel, the first flow channel is connected to the first flushing pipe and the second flow channel is connected to the second flushing pipe; A switching cavity is also provided, in which the switching piston is slidably connected. The switching spring is sleeved on the switching piston and squeezes the switching piston to block the second flow channel. The switching cavity extends to provide a control channel. The main piston is provided with a control hole. When the main piston slides, the control hole moves to connect the control channel and the water inlet pipe, and the switching piston moves to block the first flow channel, while the second flow channel opens.

[0015] A preferred technical solution is that the starting mechanism includes a pneumatic button, a starting piston, and a pressure rod. One side of the starting piston is a drain chamber, and the other side is a pressure relief chamber. The drain chamber is connected to the control chamber, and the pressure relief chamber is located on the side close to the pressure rod. When the pneumatic button is pressed, the pressure rod is lifted, and the pressure relief chamber is connected to the inside of the water tank shell. The starting piston moves towards the pressure relief chamber under the push of water pressure. At this time, the drain chamber is connected to the inside of the water tank shell.

[0016] A preferred technical solution is that a fixing frame is provided on the outside of the water tank shell, the water tank shell is fixed in the fixing frame, the fixing frame is installed at the bottom of the toilet, the second flush pipe is located at the bottom after installation, and an air breaker is provided on the first flush pipe.

[0017] Compared with the prior art, the concealed toilet flush valve of the present invention has the following technical advantages: 1. This application features a concealed toilet flush valve, achieving both aesthetic appeal and broad compatibility. By integrating the entire flush valve system into a flat tank housing and installing it in the bottom cavity of the toilet's ceramic body, it completely eliminates the space occupied by traditional mechanical flush valves behind or above the toilet, resulting in a complete and simple integrated design. Standardized piping interfaces allow it to be directly adapted as an independent module to most toilets on the market, offering strong versatility.

[0018] The fully mechanical intelligent control system is stable, reliable, and maintenance-free. It relies on a pure mechanical transmission chain consisting of a starting mechanism, a control piston, and a flow channel switching mechanism to achieve a predetermined flushing sequence and automatic switching between upper ring rinsing and bottom spraying. The entire process requires no electricity or electronic components, fundamentally avoiding problems such as circuit failure and battery depletion. It is highly adaptable to the environment, has a long lifespan, and is easy to use.

[0019] A unique negative pressure return water drying mechanism ensures hygiene and safety. Addressing the issue of water accumulation in bottom-mounted installations, an innovative drain sleeve with a one-way valve is integrated at the beginning of the flushing pipe. Utilizing the Venturi negative pressure generated during flushing, the water accumulated inside the shell is actively sucked away and emptied, achieving automatic drying of the inner cavity. At the same time, it physically prevents sewage backflow, fundamentally solving the hygiene and pollution hazards of bottom-mounted water tanks.

[0020] The optimized design of the main control valve core ensures smooth operation and adaptability to water pressure. It employs a main and auxiliary piston working in tandem and a pressure regulating gap design, decoupling the drive and sealing functions. This achieves pressure balance during valve opening and pilot shut-off during closing, effectively preventing water flow impact and water hammer effects. This results in smooth opening and closing actions, reliable sealing, and significantly improved valve core lifespan and adaptability to different inlet water pressures.

[0021] Integrating multiple anti-backflow and pressure regulation features enhances system reliability. Key components include a vacuum breaker to prevent siphon contamination of the water source, a return water structure with a one-way valve to prevent sewage backflow, and a flushing flow limiter to stabilize flow and prevent negative pressure. This multi-layered safety protection ensures stable system operation and safe water use under various operating conditions.

[0022] Other features and advantages of the invention will become clear when reading the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the invention, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without any inventive effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the concealed toilet flush valve installed on the toilet according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram of the external housing of the concealed toilet flush valve provided in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the internal cross-sectional structure of the filter tank provided in a specific embodiment of the present invention; Figure 4 This is an enlarged structural diagram of the starting mechanism provided in a specific embodiment of the present invention; Figure 5 This is an enlarged structural diagram of the control piston section provided in a specific embodiment of the present invention; Figure 6 This is a partial enlarged structural diagram of the flow channel switching mechanism provided in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of a cross-sectional view of the flushing flow restrictor provided in a specific embodiment of the present invention. In the picture: 1. Water tank shell; 11. First flush pipe; 12. Second flush pipe; 13. Inlet pipe; 2. Starting mechanism; 3. Control piston; 4. Flow channel switching mechanism; 5. Drainage sleeve; 7. Fixing bracket; 111. Air breaker; 51. Fixing ring; 52. Water guide hole; 53. Water pipe joint; 54. Return chamber; 55. One-way sealing ring; 56. Return groove; 551. Fixing part; 552. Deformation part; 31. Main piston; 32. Auxiliary piston; 33. Control chamber; 34. Water flow chamber; 341. Water outlet port; 35. Mounting hole; 351. Guide post; 352. Compression spring; 36. Water replenishment channel 37. Secondary spring; 38. Secondary sealing ring; 39. Pressure regulating gap; 311. Limiting section; 312. Pressure regulating sealing ring; 313. Control hole; 61. Flushing flow limiting plug; 62. Flow limiting cap; 63. Flow limiting spring; 611. Flow limiting column; 621. Flow limiting hole; 622. Return water pressure regulating channel; 64. Return water piston; 65. Return water spring; 41. Switching housing; 42. Switching piston; 43. Switching spring; 44. First flow channel; 45. Second flow channel; 46. Switching slide cavity; 47. Control channel; 21. Pneumatic button; 22. Start piston; 23. Pressure rod; 24. Drainage cavity; 25. Pressure relief cavity. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0026] The concealed toilet flush valve will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] like Figure 1-7As shown, a concealed toilet flush valve includes a water tank housing 1 installed at the bottom of the toilet bowl. The water tank housing 1 is equipped with a first flush pipe 11 connected to the upper part of the toilet bowl and a second flush pipe 12 connected to the bottom of the toilet bowl. The water tank housing 1 also has a water inlet pipe 13. The concealed layout makes the toilet more aesthetically pleasing and is compatible with most toilets on the market. The water tank housing 1 is a flat, well-sealed container-like structure, its shape and size specifically designed to fit the pre-reserved cavity at the rear or bottom of most toilet bowl ceramic bodies. The first flush pipe 11 extends upwards and connects to the annular flushing channel on the upper part of the toilet bowl via a pipe; the second flush pipe 12 extends downwards or horizontally and connects to the jet hole at the bottom of the toilet bowl; the water inlet pipe 13 is used to connect to the municipal water supply pipe. The entire valve body is integrated as a module and is secured inside the toilet bowl ceramic body by a mounting bracket 7 on its outer shell. This design completely conceals the traditional exposed water tank or suspended flush valve within the toilet body, resulting in a clean, streamlined, and integrated appearance that greatly enhances the product's aesthetics and modern feel. The standardized interface design allows for installation without modifying the toilet's main structure, ensuring strong compatibility and facilitating market promotion and retrofitting of existing toilets.

[0028] The water tank housing 1 is equipped with an activation mechanism 2, a control piston 3, and a flow channel switching mechanism 4. The water inlet pipe 13 is connected to the side wall of the control piston 3. When the activation mechanism 2 is pressed, it drives the control piston 3 to move back and forth. The back-and-forth movement of the control piston 3 controls the opening and closing of the flow channel switching mechanism 4. When the flow channel switching mechanism 4 is closed, the water flow from the water inlet pipe 13 passes through the control piston 3 and is discharged from the first flushing pipe 11. When the flow channel switching mechanism 4 is open, the water flow from the water inlet pipe 13 passes through the control piston 3 and is discharged from the second flushing pipe 12. Based on purely mechanical control, it does not rely on electricity and is easy to use. The activation mechanism 2, control piston 3, and flow channel switching mechanism 4 are the three core functional modules of the valve body, which are linked by hydraulic and mechanical means. The user operates the activation mechanism 2 to generate an initial trigger signal. This signal acts on the control piston 3, causing it to overcome the spring force and begin to move. The movement of piston 3 serves two key functions: first, it directly controls the opening and closing of the main water passage; second, through a specific structure on its piston rod, it changes the opening and closing state of the control water passage of the flow switching mechanism 4 when moving to different positions, thereby directing the switching mechanism to operate and changing the water outlet path. The entire control process is completed entirely by mechanical components, requiring no circuits, batteries, or solenoid valves. This gives the product extremely high reliability, long lifespan, and excellent resistance to humid environments, while completely eliminating concerns about electrical safety and the need for battery replacement. Purely mechanical transmission also means direct response and a low failure rate.

[0029] When the control piston 3 moves back and forth, some water flows into the water tank shell 1. A drain sleeve 5 is provided at the connection between the second flush pipe 12 and the flow channel switching mechanism 4. When the second flush pipe 12 drains, the water in the water tank shell 1 flows from the drain sleeve 5 into the second flush pipe 12 under negative pressure. The unique return water structure removes the water in the water tank shell 1, while avoiding toilet backflow pollution. During the flushing cycle, the drainage of the control chamber 33 of the control piston 3, possible sealing leaks, or condensation may cause a small amount of water to accumulate inside the flat water tank shell 1. This solution integrates a drain sleeve 5 at the outlet of the second flow channel 45 of the flow channel switching mechanism 4. When the flow channel switches to the second flush pipe 12 for powerful flushing, the high-speed water flow passes through the drain sleeve 5, and according to the Venturi effect, a local negative pressure zone is generated at that point. This negative pressure acts on the inside of the water tank shell 1 through the flow guide structure connected to it, thereby actively sucking out the water accumulated inside the shell like a straw, and flushing it away with the main flushing water flow. This design perfectly solves the common problem of water accumulation inside bottom-mounted flush valves. By utilizing the fluid dynamics generated during flushing, it achieves automatic drying inside the housing, preventing stagnant water from accumulating, breeding bacteria, producing odors, or forming scale. At the same time, because it uses negative pressure suction and the water flow is unidirectional, it fundamentally eliminates the possibility of sewage flowing back into the housing from the drain pipe, ensuring a high level of hygiene and safety.

[0030] The specific implementation of the return water path and the one-way sealing structure are as follows: one end of the drain sleeve 5 is fixed to one outlet end of the flow channel switching mechanism 4; a fixing ring 51 is provided on the middle side wall of the drain sleeve 5; the fixing ring 51 is fixedly connected to the water tank shell 1; a water guide hole 52 is provided in the middle of the fixing ring 51; the water guide hole 52 is connected to the inside of the water tank shell 1; a water pipe connector 53 is provided at the end of the second flushing pipe 12; the water pipe connector 53 is fixed to the water tank shell 1; a return cavity 54 is provided between the water pipe connector 53 and the fixing ring 51; the return cavity 54 connects the inside of the water pipe connector 53 and the water guide hole 52; a one-way sealing ring 55 is provided in the return cavity 54; the one-way sealing ring 55 is fixed to the end of the water guide hole 52, so that the water in the water guide hole 52 can flow into the return cavity 54 in one direction. Furthermore, the drain sleeve 5 is provided with a return groove 56, and the one-way sealing ring 55 is fixed in the return groove 56. The one-way sealing ring 55 is provided with a fixing part 551 and a deformable part 552. The thickness of the fixing part 551 is greater than the thickness of the deformable part 552. The fixing part 551 is sleeved on the return groove 56, and the deformable part 552 extends from the fixing part 551 until it covers the water guide hole 52. The drain sleeve 5 is sealed to the wall of the water tank shell 1 through its fixing ring 51, and the water guide hole 52 becomes the only channel between the inside of the shell and the return cavity 54. The one-way sealing ring 55 is firmly stuck in the return groove 56. Its thick fixing part 551 ensures a firm installation, while the thin and flexible deformable part 552 acts like a one-way valve. When the second flush pipe 12 generates negative pressure, the pressure in the return chamber 54 decreases. Water accumulated in the water tank housing 1 is pushed open by air pressure, and enters the return chamber 54 through the guide hole 52, subsequently flowing into the main water flow. When flushing ends or abnormal positive pressure occurs, the deformation part 552, under water pressure or its own elasticity, tightly covers the guide hole 52, achieving a seal. This structure provides an extremely simple and reliable one-way valve solution. The retaining ring 51 ensures a stable and sealed installation; the special one-way sealing ring 55 design guarantees both the robustness of the installation and the sensitivity of the valve disc's action and the reliability of the seal. It is not prone to fatigue failure over long-term use, effectively maintaining the long-lasting effectiveness of the return water drying function and providing a safety barrier against backflow.

[0031] The detailed structure and preferred technical solution for smooth control of the control piston 3 are as follows: the control piston 3 includes a main piston 31 and a secondary piston 32. The main piston 31 is divided into a control chamber 33 and a water flow chamber 34 on both sides. The main piston 31 is slidably connected in the control chamber 33. The starting mechanism 2 is connected to the control chamber 33. When the starting mechanism 2 is activated, the control chamber 33 communicates with the interior of the water tank shell 1. Under water pressure, the main piston 31 slides to discharge water from the control chamber 33 to the water tank shell 1. The water inlet pipe 13 communicates with the water flow chamber 34. The water flow chamber 34 is provided with a water outlet port 341 connected to the flow channel switching mechanism 4. When the main piston 31 is reset, it squeezes the secondary piston 32 to abut against the water outlet port 341, cutting off the water channel between the water inlet pipe 13 and the flow channel switching mechanism 4. The main piston 31 is a rod-shaped member with a piston head, which divides the cylindrical piston chamber into the non-communicating control chamber 33 and water flow chamber 34. The starting mechanism 2 controls the connection and disconnection between the control chamber 33 and the low-pressure area inside the water tank shell 1. When the starting mechanism 2 is activated, the control chamber 33 is depressurized, and the high-pressure water in the water flow chamber 34 pushes the main piston 31 towards the control chamber 33, completing the opening stroke. During this stroke, the upper ring is flushed through the first drain pipe. The auxiliary piston 32 is fitted onto the rod of the main piston 31 and is located inside the water flow chamber 34. During the closing process, the main piston 31 is reset under the action of the compression spring 352, and the end of its rod pushes the auxiliary piston 32 towards the water outlet port 341 until the sealing ring on the auxiliary piston 32 presses against the port, closing the water passage. The main and auxiliary pistons 32 are designed separately, decoupling the driving function from the sealing function. The main piston 31 is responsible for the large stroke motion control, while the auxiliary piston 32 is dedicated to precision sealing. This design reduces the motion resistance of the main piston 31, making its operation smoother, while allowing the auxiliary piston 32 and its sealing ring to be independently optimized for the best sealing effect, improving overall reliability and lifespan.

[0032] The reset, guiding, and automatic water replenishment scheme of the main piston 31 is as follows: A mounting hole 35 is provided in the middle of the main piston 31. A guide post 351 and a compression spring 352 are installed in the mounting hole 35. The compression spring 352 is sleeved on the guide post 351, providing a force to the main piston 31 to move towards the water outlet 341. A water replenishment channel 36 is provided on the main piston 31, connecting the mounting hole 35 and the water flow chamber 34. When the main piston 31 resets, water from the water flow chamber 34 enters the control chamber 33 after passing through the water replenishment channel 36 and the mounting hole 35. The guide post 351 is fixed to the end of the piston chamber, passing through the mounting hole 35 of the main piston 31, providing precise radial positioning for the reciprocating motion of the main piston 31, preventing uneven wear and jamming. The compression spring 352 provides a constant reset force. The water replenishment channel 36 is a small channel formed on the main piston 31. When the main piston 31 resets, its mounting hole 35 and water supply channel 36 connect the high-pressure water flow chamber 34 to the control chamber 33, allowing water to be slowly injected into the control chamber 33. The guide post 351 ensures precise control; the spring provides reliable reset force independent of water pressure. The design of the water supply channel 36 is crucial; it automatically replenishes the control chamber 33 with high-pressure water after each flushing cycle, ensuring the control chamber 33 is always full of water. This prepares the main piston 31 for sufficient water pressure thrust during the next start-up, guaranteeing the stability and consistency of the system's continuous operation. The size of the water supply hole determines the reset speed and controls the flushing time.

[0033] A secondary spring 37 is fitted onto the secondary piston 32. One end of the secondary spring 37 abuts against the water outlet port 341, and the secondary spring 37 exerts a force on the secondary piston 32 to move it away from the water outlet port 341. A secondary sealing ring 38 is provided in the middle of the secondary piston 32. When closed, the secondary sealing ring 38 abuts against the water outlet port 341. A pressure regulating gap 39 is provided between the secondary piston 32 and the main piston 31. The main piston 31 has a limiting section 311, and the secondary piston 32 is restricted to sliding only on the limiting section 311. A pressure regulating sealing ring 312 is provided at the end of the limiting section 311. When the main piston 31 returns to its original position, the pressure regulating sealing ring 312 abuts against the end of the secondary piston 32. The secondary spring 37 keeps the secondary piston 32 in a constant tendency to open. When open, the main piston 31 moves a small distance first, opening the pressure regulating gap 39. High-pressure water quickly fills the rear space of the secondary piston 32 through this gap, balancing the pressure at both ends. Subsequently, under the slight thrust of the auxiliary spring 37, the auxiliary piston 32 smoothly retracts, opening the water outlet port 341, avoiding explosive opening caused by direct impact from high-pressure water. Upon closing, the main piston 31 resets, and its pressure-regulating sealing ring 312 first contacts and seals the end of the auxiliary piston 32, cutting off the water supply to the pressure-regulating gap 39 and isolating the pressure at the rear of the auxiliary piston 32. The main piston 31 continues to advance, mechanically pushing the now pressure-free auxiliary piston 32 to complete the seal. The cooperation between the pressure-regulating gap 39 and the pressure-regulating sealing ring 312 is key to achieving smooth valve opening and closing and eliminating water hammer. It ensures smooth, impact-free opening, and upon closing, first removes the sealing back pressure before final tightening, greatly reducing wear on the sealing ring and impact noise, significantly improving valve lifespan and user experience.

[0034] The pressure regulation and anti-siphon technology of the first flush pipe 11 is as follows: a flushing flow restrictor 61 is fixedly installed at the end of the first flush pipe 11; a flow restrictor cap 62 is slidably installed in the first flush pipe 11; a flow restrictor column 611 is installed in the middle of the flushing flow restrictor 61; a flow restrictor spring 63 is sleeved on the flow restrictor column 611; one end of the flow restrictor spring 63 abuts against the flow restrictor cap 62, causing the flow restrictor cap 62 to have a tendency to move away from the flushing flow restrictor 61; a flow restrictor orifice 621 is installed in the middle of the flow restrictor cap 62; when the water pressure increases, the flow restrictor cap 62 moves towards the flow restrictor column 611; the flow restrictor column 611... The gap between the first flush pipe 11 and the flow-limiting cap 62 is reduced. A return water pressure regulating channel 622 is provided on the side of the flow-limiting cap 62 near the water inlet. The return water pressure regulating channel 622 is connected to the interior of the water tank shell 1. A return water piston 64 and a return water spring 65 are provided in the return water pressure regulating channel 622. The return water spring 65 abuts against the return water piston 64, causing the return water piston 64 to close the return water pressure regulating channel 622. When a negative pressure is formed in the first flush pipe 11, the return water piston 64 squeezes the return water spring 65, opening the return water pressure regulating channel 622. This component integrates constant flow and vacuum breaking functions. Under the action of the flow-limiting spring 63, the flow-limiting cap 62 maintains a large gap between its flow-limiting orifice 621 and the flow-limiting column 611. When the inlet water pressure increases, the thrust of the water flow on the flow-limiting cap 62 increases, overcoming the spring force and causing it to move towards the flow-limiting column 611. The gap becomes smaller, the throttling effect is enhanced, thereby stabilizing the output flow and achieving water saving. The return water pressure regulating channel 622 is a bypass, and the return water piston 64 inside it is normally closed under the action of the return water spring 65. When negative pressure is generated in the first flush pipe 11 due to siphon or other reasons, the external atmospheric pressure pushes the return water piston 64 through the water tank shell 1 to overcome the spring force and open, allowing air to enter the pipe and breaking the vacuum. The constant flow function keeps the flow rate of the upper flush stable under different water pressures, ensuring the flushing effect while saving water. The integrated vacuum breaker provides anti-siphon protection for the first flush pipe 11, preventing the potential risk of the toilet water seal being sucked dry or sewage backflow, and has a compact structure that does not occupy additional space.

[0035] The flow channel switching mechanism 4 is hydraulically controlled. The flow channel switching mechanism 4 includes a switching housing 41, a switching piston 42, and a switching spring 43. The switching housing 41 is provided with a first flow channel 44 and a second flow channel 45. The first flow channel 44 is connected to the first flushing pipe 11, and the second flow channel 45 is connected to the second flushing pipe 12. A switching slide cavity 46 is also provided. The switching piston 42 is slidably connected in the switching slide cavity 46. The switching spring 43 is sleeved on the switching piston 42 and squeezes the switching piston 42 to block the second flow channel 45. The switching slide cavity 46 extends to provide a control channel 47. The main piston 31 is provided with a control hole 313. When the main piston 31 slides, the control hole 313 moves to connect the control channel 47 and the water inlet pipe 13. The switching piston 42 moves to block the first flow channel 44, and the second flow channel 45 opens. The flow channel switching mechanism 4, by default, operates under the action of the switching spring 43, with the switching piston 42 blocking the second flow channel 45, allowing water to flow only from the first flow channel 44 for the upper flush. The control channel 47 connects to one end of the switching chamber 46. A control hole 313 is provided on the main piston 31 rod. When the main piston 31 moves to a specific position in the flushing sequence, this control hole 313 precisely connects the high-pressure water inlet pipe 13 to the control channel 47. High-pressure water enters the switching chamber 46, pushing the switching piston 42 to compress the switching spring 43, thereby changing the flow channel state and switching to the second flow channel 45 for bottom flushing. By utilizing the mechanical position of the main piston 31 to precisely control the timing of hydraulic signal transmission, a rigid linkage between flow channel switching and the main flushing sequence is achieved. This ensures that the scientific process of flushing the upper chamber first and then spraying the bottom is followed, optimizing the flushing effect. The hydraulic control force is strong and the operation is reliable. When the pneumatic button 21 is pressed, the control chamber 33 of the main piston 31 is depressurized, causing the water flow to propel it forward. At this time, flushing begins, and water flows from the first flow channel 44 to flush the upper rim of the toilet. Because the main piston 31 is depressurized, the flushing water pressure is significantly reduced during this process, achieving a gentle, throttling flush. When the main piston 31 resets, the initial flushing pressure increases to flush the upper rim. Soon, the control channel 47 is opened, allowing for a high-flow flush of the bottom. During this process, because the water flow is not depressurized, the flushing pressure is relatively high.

[0036] A preferred technical solution is that the starting mechanism 2 includes a pneumatic button 21, a starting piston 22, and a pressure rod 23. One side of the starting piston 22 is a drain chamber 24, and the other side is a pressure relief chamber 25. The drain chamber 24 is connected to the control chamber 33. The pressure relief chamber 25 is located near the pressure rod 23. When the pneumatic button 21 is pressed, the pressure rod 23 is lifted, and the pressure relief chamber 25 becomes connected to the interior of the water tank housing 1. The starting piston 22 moves towards the pressure relief chamber 25 under water pressure, thus maintaining communication between the drain chamber 24 and the interior of the water tank housing 1. The pneumatic button 21 is connected to the pressure relief chamber 25 of the starting mechanism 2 via a flexible hose. When the button is pressed, compressed air pushes the pressure rod 23 up through the hose, opening the seal of the pressure relief chamber 25. Since the drain chamber 24 is always connected to the control chamber 33 via a pipe, it is filled with high-pressure water. After the pressure relief chamber 25 is opened, the starting piston 22 moves towards the pressure relief chamber 25 under the action of high-pressure water in the drain chamber 24, thereby opening the channel between the drain chamber 24 and the water tank shell 1. This causes the control chamber 33 to start draining and releasing pressure, triggering the main piston 31 to act. Pneumatic control achieves physical separation between the button and the valve body, allowing the button to be flexibly installed in any convenient location, such as the water tank lid or the side wall of the toilet, offering a high degree of design freedom. Simultaneously, pneumatic transmission avoids the friction and jamming problems of mechanical linkages, resulting in a light and reliable operating feel.

[0037] A preferred technical solution is that a fixing bracket 7 is provided on the outside of the water tank shell 1, and the water tank shell 1 is fixed in the fixing bracket 7. The fixing bracket 7 is installed at the bottom of the toilet, and after installation, the second flush pipe 12 is located at the bottom. An air breaker 111 is provided on the first flush pipe 11. The fixing bracket 7 serves as a transition component, facilitating the secure installation of the integrated valve body module onto the bottom mounting surface of different toilet models. Ensuring that the second flush pipe 12 is in the lowest position facilitates the use of gravity to drain any remaining water. The air breaker 111 installed on the first flush pipe 11 can quickly draw in air when negative pressure is generated in the pipe, providing additional anti-siphon protection. The fixing bracket 7 enhances the versatility and stability of the installation. As a redundant safety design, the air breaker 111, together with the integrated anti-siphon structure in the first flush pipe 11, forms a double insurance, greatly improving the safety of the entire water supply path and fully complying with strict sanitary ware water supply safety standards.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or apparatus that includes that element.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. The present invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hidden toilet flushing valve, characterized in that: a water tank shell is installed at the bottom end of the inside of the toilet, the water tank shell is provided with a first flushing pipe connected with the upper ring of the toilet and a second flushing pipe connected with the bottom of the toilet, and the water tank shell is further provided with a water inlet pipe; a starting mechanism, a control piston and a flow channel switching mechanism are arranged in the water tank shell, the water inlet pipe is connected with the side wall of the control piston, when the starting mechanism is pressed, the control piston is driven to move back and forth, the control piston moves back and forth to control the opening and closing of the flow channel switching mechanism, when the flow channel switching mechanism is closed, the water flow of the water inlet pipe is discharged from the first flushing pipe after passing through the control piston, when the flow channel switching mechanism is opened, the water flow of the water inlet pipe is discharged from the second flushing pipe after passing through the control piston; part of the water flow enters the water tank shell when the control piston moves back and forth, a drain sleeve is arranged at the connection between the second flushing pipe and the flow channel switching mechanism, when the second flushing pipe discharges water, the water in the water tank shell flows into the second flushing pipe from the drain sleeve under the action of negative pressure.

2. The hidden toilet flushing valve according to claim 1, characterized in that: one end of the drain sleeve is fixed on one water outlet end of the flow channel switching mechanism, a fixed ring is arranged on the middle part of the side wall of the drain sleeve, the fixed ring is fixedly connected with the water tank shell, a water guide hole is arranged in the middle part of the fixed ring, and the water guide hole is in communication with the inside of the water tank shell; a water pipe joint is arranged at the end of the second flushing pipe, the water pipe joint is fixed on the water tank shell, a backflow cavity is arranged between the water pipe joint and the fixed ring, the backflow cavity is in communication with the inside of the water pipe joint and the water guide hole, a one-way sealing ring is arranged in the backflow cavity, and the one-way sealing ring is fixed on the end of the water guide hole, so that the water in the water guide hole can flow into the backflow cavity in one direction.

3. The hidden toilet flushing valve according to claim 2, characterized in that: a backflow clamping groove is arranged on the drain sleeve, the one-way sealing ring is fixed in the backflow clamping groove, the one-way sealing ring is provided with a fixed part and a deformation part, the thickness of the fixed part is greater than that of the deformation part, the fixed part is sleeved on the backflow clamping groove, and the deformation part extends from the fixed part to cover the water guide hole.

4. The hidden toilet flushing valve according to claim 1, characterized in that: the control piston comprises a main piston and a secondary piston, the two sides of the main piston are separated into a control cavity and a water flow cavity, the main piston is slidingly connected in the control cavity, the starting mechanism is connected with the control cavity, when the starting mechanism is opened, the control cavity is in communication with the inside of the water tank shell, and the main piston slides under the action of water pressure to discharge the water in the control cavity to the water tank shell; the The water inlet pipe is in communication with 5. The hidden toilet flushing valve according to claim 4, characterized in that: The water flow cavity is provided with a water outlet port connected with the flow channel switching mechanism, when the main piston resets, the secondary piston is pressed against the water outlet port, cutting off the water channel between the water inlet pipe and the flow channel switching mechanism. an installation hole is arranged in the middle part of the main piston, a guide column and a compression spring are arranged in the installation hole, the compression spring is sleeved on the guide column, and the compression spring provides a force for the main piston to move to the water outlet port. ​ The main piston is provided with a water supplement channel, which communicates the mounting hole with the water flow cavity, and when the main piston resets, the water in the water flow cavity enters the control cavity through the water supplement channel and the mounting hole.

6. The concealed toilet flush valve of claim 5, wherein: The auxiliary piston is sleeved with an auxiliary spring, one end of the auxiliary spring abuts against the water outlet port, and the auxiliary spring gives the auxiliary piston an acting force away from the water outlet port, and the auxiliary piston is provided with an auxiliary sealing ring in the middle part, which abuts against the water outlet port when closed; The auxiliary piston and the main piston are provided with a pressure regulating gap, the main piston is provided with a limiting section, the auxiliary piston is limited to slide on the limiting section only, and the end of the limiting section is provided with a pressure regulating sealing ring, which abuts against the end of the auxiliary piston when the main piston resets.

7. The concealed toilet flush valve of claim 1, wherein: The end of the first flush pipe is fixedly provided with a flush flow limiting plug, the first flush pipe is slidably provided with a flow limiting cap, the middle part of the flush flow limiting plug is provided with a flow limiting column, the flow limiting column is sleeved with a flow limiting spring, one end of the flow limiting spring abuts against the flow limiting cap, so that the flow limiting cap has a movement tendency away from the flush flow limiting plug; the middle part of the flow limiting cap is provided with a flow limiting hole, when the water pressure increases, the flow limiting cap moves to the flow limiting column, and the gap between the flow limiting column and the flow limiting cap decreases; The side close to the water inlet end of the flow limiting cap is provided with a backwater pressure regulating channel, which communicates with the inside of the water tank shell, the backwater pressure regulating channel is provided with a backwater piston, and the backwater pressure regulating channel is also provided with a backwater spring, which abuts against the backwater piston, so that the backwater piston closes the backwater pressure regulating channel, when negative pressure is formed in the first flush pipe, the backwater piston extrudes the backwater spring, and the backwater pressure regulating channel is opened.

8. The concealed toilet flush valve of claim 1, wherein: The flow channel switching mechanism includes a switching shell, a switching piston and a switching spring, the switching shell is provided with a first flow channel and a second flow channel, the first flow channel communicates with the first flush pipe, and the second flow channel communicates with the second flush pipe; A switching sliding cavity is also provided, the switching piston is slidably connected in the switching sliding cavity, the switching spring is sleeved on the switching piston and extrudes the switching piston to block the second flow channel, the switching sliding cavity is extended to be provided with a control channel, the main piston is provided with a control hole, when the main piston slides, the control hole moves to the control channel and the water inlet pipe, the switching piston moves to block the first flow channel, and the second flow channel is opened.

9. The concealed toilet flush valve of claim 4, wherein: The starting mechanism comprises a pneumatic button, a starting piston, a pressing rod, one side of the starting piston is a drainage cavity, the other side is a pressure relief cavity, the drainage cavity is communicated with the control cavity, the pressure relief cavity is located on the side close to the pressing rod, when the pneumatic button is pressed, the pressing rod is lifted, the pressure relief cavity is communicated with the inside of the water tank shell, the starting piston is moved to the direction of the pressure relief cavity under the water pressure, at this time, the drainage cavity is communicated with the inside of the water tank shell.

10. The concealed toilet flush valve of claim 1, wherein: The water tank shell is provided with a fixing frame outside, the water tank shell is fixed in the fixing frame, the fixing frame is installed at the bottom of the toilet, after installation, the second flush pipe is located at the bottom end, and the air breaker is arranged on the first flush pipe.

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