Dual flow control mechanical flush valve

Abstract

The utility model discloses a double flow control mechanical flush valve belongs to closestool technical field, including main pneumatic valve and deputy pneumatic valve for with control piston connection, small button, big button and three -way connection valve of row button, big button is with small button with three -way connection valve connection simultaneously, the gas -out end of three -way connection valve is with control end connection of main pneumatic valve, small button is with deputy pneumatic valve control end connection, set up two buttons to correspond to different flush demand, save closestool water. When pressing small button, main pneumatic valve and deputy pneumatic valve open simultaneously, the control piston is drained to main pneumatic valve direction, until main pneumatic valve closes, when the control piston negative pressure water absorption resets, deputy pneumatic valve replenishes water to it, until flush end deputy pneumatic valve closes. Deputy pneumatic valve replenishes water to control piston in reset stage, make and improve control piston reset speed, reduce flush time.

Description

Technical Field

[0001] This utility model relates to the field of toilet technology, and in particular to a dual-flow control mechanical flush valve. Background Technology

[0002] Fall-down flushing, a classic toilet operating principle, utilizes the gravity and kinetic energy of water flow to expel waste. In traditional designs, when the user activates the flushing device, the water stored in the tank, under the influence of gravity, flows directly through the steep walls and a concentrated water flow path, impacting the toilet bowl area and using the physical impact force of the water flow to flush waste out of the drain pipe. This flushing method relies primarily on positive pressure throughout the flushing process, unlike siphon toilets which require negative pressure in the pipes.

[0003] Mechanical flush control valves are inconvenient to operate, and existing technologies cannot achieve pneumatic micro-force control, nor can they achieve linkage control of two valve bodies to control the flush volume. Summary of the Invention

[0004] To address the aforementioned problems, this utility model aims to solve the problems described above. One objective of this utility model is to provide a dual-flow control mechanical flushing valve for purely mechanical flushing toilets, achieving both large and small flushing control based on mechanical control.

[0005] The solution adopted in this utility model is: a dual-flow control mechanical flushing valve, including a main pneumatic valve and an auxiliary pneumatic valve for connection with a control piston, a small discharge button, a large discharge button, and a three-way connecting valve; the large discharge button and the small discharge button are simultaneously connected to the three-way connecting valve, the air outlet of the three-way connecting valve is connected to the control end of the main pneumatic valve, and the small discharge button is connected to the control end of the auxiliary pneumatic valve; When the large drain button is pressed, the main pneumatic valve opens, and the control piston drains water towards the main pneumatic valve until the main pneumatic valve closes. At this point, the control piston returns to its negative pressure state and retracts water. When the small drain button is pressed, both the main pneumatic valve and the auxiliary pneumatic valve open simultaneously. The control piston drains water towards the main pneumatic valve until the main pneumatic valve closes. At this point, the auxiliary pneumatic valve replenishes water to the control piston until the flushing is complete and the auxiliary pneumatic valve closes.

[0006] Specifically, the auxiliary pneumatic valve includes a control valve body, a water supply pipe, and a water flow control rod. The water supply pipe is installed on the side wall of the water inlet pipe. The control valve body slides back and forth under the control of the small discharge button. One end of the water flow control rod is fixed to the control output end of the control valve body. A water supply hole is provided in the middle of the water supply pipe. The water flow control rod passes through the water supply hole and is connected to it with a gap. When the control valve body is opened, water from the water inlet pipe enters the water supply pipe and passes through the gap between the water flow control rod and the water supply hole.

[0007] A preferred technical solution is that the control valve body includes a valve piston, a valve spring, and a valve cavity. The valve piston is slidably connected in the valve cavity, and one end of the valve spring abuts against the valve piston. When started, the valve piston squeezes the valve spring under water pressure, and resets under the action of the valve spring when the pressure difference disappears.

[0008] To facilitate easier start-up, the control valve body also includes a sealing cap, a pressure rod, and a pressure spring. An opening flow channel is provided on the side of the valve cavity where the valve spring is installed. In the initial state, the pressure rod squeezes the sealing cap under the action of the pressure spring, and the sealing cap blocks the opening flow channel. When opening, the pressure rod lifts up and holds the sealing cap in place under water pressure until the water in the valve cavity is drained. The sealing cap then resets under the action of the pressure spring and blocks the opening flow channel.

[0009] To control the water replenishment rate and prevent clogging, the valve spring is equipped with an extension guide rod that passes through the valve piston. When the valve piston resets, the valve cavity replenishes water through the gap between the extension guide rod and the valve piston to balance the negative pressure.

[0010] A preferred technical solution is that the main pneumatic valve includes a control valve body and a drain nozzle. The drain nozzle is installed at the end of the valve cavity of the control valve body. When not open, the valve piston blocks the channel between the drain nozzle and the water storage tank. When the main pneumatic valve is open, the valve cavity is connected to the water storage tank through the drain nozzle, and the control piston discharges water from the drain nozzle. The control valve body of the main pneumatic valve has the same structure as the control valve body of the auxiliary pneumatic valve.

[0011] To achieve coordinated control, a connecting water supply pipe is provided between the drain nozzle and the water supply pipe. When the main pneumatic valve is closed, the water in the inlet pipe enters the valve cavity of the main pneumatic valve through the water supply hole to supply water to the control piston.

[0012] To facilitate pneumatic control, the control valve body also includes an airbag lifting section. Both the small and large airbag buttons are equipped with pressing airbags inside. The pressing airbags are connected to the airbag lifting section. The top of the airbag lifting section abuts against one end of the pressure rod. When the small or large airbag button is pressed, the airbag lifting section lifts one end of the pressure rod.

[0013] The preferred technical solution is that the three-way connecting valve includes a three-way housing and a switching sleeve, the small drain button and the large drain button are connected to both ends of the three-way housing, the side wall of the three-way housing is provided with an air outlet pipe, the switching sleeve is slidably connected in the three-way housing, pressing the small drain button pushes the switching sleeve to slide to the other end, so that the small drain button is connected to the air outlet pipe.

[0014] Compared with the prior art, the dual-flow control mechanical flushing valve of this utility model has the following technical advantages: 1. This application discloses a dual-flow-control mechanical flushing valve, comprising a main pneumatic valve and an auxiliary pneumatic valve for connection to a control piston, a small flush button, a large flush button, and a three-way connecting valve; the large flush button and the small flush button are simultaneously connected to the three-way connecting valve, the air outlet of the three-way connecting valve is connected to the control end of the main pneumatic valve, and the small flush button is connected to the control end of the auxiliary pneumatic valve; the two buttons correspond to different flushing needs, saving toilet water. The two control valves work together to enable the mechanical toilet to achieve different flushing volumes.

[0015] When the large drain button is pressed, the main pneumatic valve opens, and the control piston drains water towards the main pneumatic valve until the main pneumatic valve closes. At this point, the control piston returns to its negative pressure state and draws water in, resetting. When the small drain button is pressed, both the main and auxiliary pneumatic valves open simultaneously. The control piston drains water towards the main pneumatic valve until the main pneumatic valve closes. During the negative pressure water draw-in resetting phase, the auxiliary pneumatic valve replenishes water to the control piston until the flushing is complete and then closes. The auxiliary pneumatic valve replenishes water to the control piston during the reset phase, increasing the reset speed and reducing flushing time.

[0016] Other features and advantages of the present invention will become clear when reading the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present 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.

[0018] Figure 1 This is a schematic diagram of the overall structure of the dual-flow control mechanical flushing valve provided in a specific embodiment of this utility model; Figure 2 This is provided in a specific embodiment of the present utility model. Figure 1 Enlarged diagram of section B; Figure 3 This is provided in a specific embodiment of the present utility model. Figure 1 Enlarged structural diagram of section C; Figure 4 This is provided in a specific embodiment of the present utility model. Figure 1 Enlarged structural diagram of section D in the middle; Figure 5This is provided in a specific embodiment of the present utility model. Figure 1 Enlarged structural diagram of section E in the middle.

[0019] In the picture: 4. Inlet pipe; 6. Control piston; 20. Control valve body; 21. Large drain button; 22. Three-way connecting valve; 23. Small drain button; 24. Auxiliary pneumatic valve; 25. Main pneumatic valve; 26. Air outlet pipe; 27. Water supply pipe; 28. Water flow control rod; 281. Water supply hole; 201. Valve piston; 202. Valve spring; 203. Valve cavity; 204. Sealing cap; 205. Pressure rod; 206. Compression spring; 207. Airbag lifting part; 2021. Extension guide rod; 251. Drain nozzle; 29. ​​Connecting water supply pipe; 234. Press airbag; 221. Three-way housing; 222. Switching sleeve. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. 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.

[0021] The dual-flow control mechanical flushing valve will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figure 1-5 As shown, this embodiment details a dual-flow control mechanical flushing valve. This valve is the core control component of a drop-type mechanical flushing tank, and through a purely mechanical and pneumatic structure, it achieves reliable switching and precise control between two flushing modes: large-flow and small-flow.

[0023] The dual-flow control mechanical flushing valve mainly includes a main pneumatic valve 25, an auxiliary pneumatic valve 24, a small flush button 23, a large flush button 21, and a three-way connecting valve 22. The large flush button 21 and the small flush button 23 are both connected to the three-way connecting valve 22. The outlet of the three-way connecting valve 22 is connected to the control terminal of the main pneumatic valve 25, and the small flush button 23 is connected to the control terminal of the auxiliary pneumatic valve 24. This connection constitutes a simple pneumatic logic circuit. When the user presses the large flush button 21, the generated airflow is transmitted to the control terminal of the main pneumatic valve 25 only through the three-way connecting valve 22, causing it to open independently. When the user presses the small flush button 23, the generated airflow is divided into two paths: one path directly drives the auxiliary pneumatic valve 24 to open; the other path drives the main pneumatic valve 25 to open through the three-way connecting valve 22, thereby achieving simultaneous opening of the main and auxiliary pneumatic valves 24.

[0024] The core control logic of the flushing mode is as follows: When the large drain button 21 is pressed, the main pneumatic valve 25 opens, and the control piston 6 drains water towards the main pneumatic valve 25 until the main pneumatic valve 25 closes. At this point, the control piston 6 returns to its negative pressure state and draws water in, resetting. When the small drain button 23 is pressed, both the main pneumatic valve 25 and the auxiliary pneumatic valve 24 open simultaneously. The control piston 6 drains water towards the main pneumatic valve 25 until the main pneumatic valve 25 closes. At this point, the auxiliary pneumatic valve 24 replenishes water to the control piston 6, and the flushing ends when the auxiliary pneumatic valve 24 closes. Large drain mode: Only the main pneumatic valve 25 is opened, providing a single channel for the drainage of the control piston 6. When the control piston 6 resets, its control chamber slowly draws water through the gap channel within the control piston 6 itself to balance the pressure. The reset speed is relatively slow, resulting in a longer effective flushing time and a larger total drainage volume. Small drain mode: Both the main pneumatic valve 25 and the auxiliary pneumatic valve 24 are opened simultaneously. The opening of the auxiliary pneumatic valve 24 provides a second water supply channel from the high-pressure water inlet pipe 4 to the control chamber of the control piston 6. During the reset process of the control piston 6, high-pressure water continuously supplies water to the control chamber through the auxiliary pneumatic valve 24. The rapid pressure balance causes the control piston 6 to reset quickly under the spring force, thus significantly reducing the reset time of the control piston 6. This results in a shorter effective flushing time and a reduction in total drainage volume. By whether or not high-pressure water is introduced into the control chamber, the reset dynamics of the control piston 6 are cleverly altered, thereby precisely controlling the effective opening time of the flushing valve. This is a very ingenious fully mechanical flow control method that meets the user's needs for water conservation during small discharges and strong flushing during large discharges.

[0025] The detailed structure and working process of the auxiliary pneumatic valve 24 are as follows: The auxiliary pneumatic valve 24 includes a control valve body 20, a water supply pipe 27, and a water flow control rod 28. The water supply pipe 27 is installed on the side wall of the inlet pipe 4 and is directly connected to the high-pressure water source. The control valve body 20 slides back and forth under the pneumatic control of the small drain button 23. One end of the water flow control rod 28 is fixed to the control output end of the control valve body 20 and moves synchronously with it. A precision water supply hole 281 is provided in the middle of the water supply pipe 27, and the water flow control rod 28 passes through the water supply hole 281 and maintains a precise clearance fit with it. When the small drain button 23 is pressed, the control valve body 20 opens and drives the water flow control rod 28 to move, so that the annular gap between the water flow control rod 28 and the water supply hole 281 is opened. At this time, the high-pressure water in the inlet pipe 4 enters the water supply pipe 27 and flows out at high speed through the annular gap into the subsequent pipeline. The gap connection between the water flow control rod 28 and the water inlet hole 281 serves two purposes. First, it acts as a throttle valve, allowing precise control of the water supply and thus precise regulation of the flushing volume in the small-discharge mode. Second, the high-speed water flow through the gap has a self-cleaning effect, effectively preventing scale or impurities from accumulating and clogging the channel, ensuring long-term reliability.

[0026] The core driving mechanism of the control valve body 20 lies in the fact that the control valve body 20 includes a valve piston 201, a valve spring 202, and a valve cavity 203. The valve piston 201 is slidably connected in the valve cavity 203, dividing the valve cavity 203 into upper and lower chambers. One end of the valve spring 202 abuts against the valve piston 201, and the other end abuts against the valve cavity 203. In the closed state, the elastic force of the valve spring 202 is balanced by the water pressure and friction in the upper chamber of the valve piston 201, keeping the valve piston 201 in the closed position. When a pneumatic opening signal is received, the upper chamber of the valve piston 201 is connected to the atmosphere, and the pressure drops sharply. At this time, under the action of the high-pressure water in the lower chamber, the valve piston 201 quickly compresses the valve spring 202 and slides upward, opening the valve. When the pneumatic signal disappears, the upper chamber closes again, and high-pressure water from the lower chamber slowly seeps into the upper chamber through a specially designed microchannel. Once the pressure in the upper and lower chambers gradually balances, the valve piston 201 resets under the restoring force of the valve spring 202, closing the valve. This structure utilizes water pressure as the primary driving force to open the valve, providing strong force and rapid action; it uses spring force and hydraulic balance for reset, ensuring smooth and reliable operation. The entire valve body does not require direct electromagnetic force for opening and closing, making it energy-efficient and structurally robust.

[0027] For easier start-up, the control valve body 20 also includes a sealing cap 204, a pressure rod 205, and a pressure spring 206. The valve cavity 203 has an opening flow channel on the side where the valve spring 202 is installed; this side is the upper chamber. Initially, the pressure rod 205, under the action of the pressure spring 206, presses downwards against the sealing cap 204, causing the sealing cap 204 to tightly seal the opening flow channel. When the valve needs to be opened, an external force lifts the pressure rod 205 upwards, relieving the pressure on the sealing cap 204. At this time, the water pressure in the upper chamber of the valve piston 201 pushes the lightweight sealing cap 204 upwards from the inside, instantly opening the opening flow channel and connecting the upper chamber to the atmosphere or a drain pipe, thus achieving rapid valve opening. When the external force disappears, the pressure rod 205 returns to its original position under the action of the pressure spring 206, pressing the sealing cap 204 back onto the opening flow channel and sealing it. This design separates the action of the long-stroke lever 205 from the opening and closing of the tiny sealing cap 204. The user only needs to lift the lever 205 with minimal force, while the seal is opened by internal water pressure, making the button operation very easy and enhancing the user experience. Simultaneously, the small sealing surface of the sealing cap 204 facilitates reliable sealing.

[0028] To control the water replenishment rate and prevent clogging, the valve spring 202 is equipped with an extension guide rod 2021, which passes through a through hole in the middle of the valve piston 201. When the valve piston 201 resets, the lower chamber of the valve cavity 203 slowly replenishes water to the upper chamber through a tiny gap between the extension guide rod 2021 and the through hole of the valve piston 201 to balance the negative pressure. This tiny gap forms a precise throttling channel. When the valve needs to close, water is slowly replenished to the upper chamber of the valve piston 201 through this gap, gradually balancing the pressure between it and the lower chamber. This allows the valve piston 201 to reset smoothly and slowly under the action of the valve spring 202, avoiding water hammer impact caused by rapid closure. The extension guide rod 2021 has both guiding and throttling functions. First, it ensures the linearity of the movement of the valve piston 201 and prevents jamming; second, the size of the throttling channel determines the valve's closing delay, giving the control piston 6 sufficient time to complete its stroke; third, the channel is not easily blocked, ensuring the stability of the system's long-term operation.

[0029] The structure and coordinated water replenishment scheme of the main pneumatic valve 25 are as follows: the main pneumatic valve 25 includes the control valve body 20 and the drain nozzle 251. The drain nozzle 251 is installed at the end of the valve cavity 203 of the control valve body 20. When not open, the valve piston 201 blocks the channel between the drain nozzle 251 and the water storage tank under the action of spring force. When the main pneumatic valve 25 is open, the valve cavity 203 is connected to the water storage tank through the drain nozzle 251, and the water in the control chamber of the control piston 6 can be discharged from the drain nozzle 251 to the water storage tank. The control valve body 20 of the main pneumatic valve 25 has the same structure as the control valve body 20 of the auxiliary pneumatic valve 24, realizing the generalization and standardized production of parts. As the main channel for drainage of the control piston 6, the opening and closing of the main pneumatic valve 25 directly controls the start and end of the flushing cycle. In order to achieve coordinated control, a connecting water replenishment pipe 29 is provided between the drain nozzle 251 and the water replenishment pipe 27. When the main pneumatic valve 25 is closed, some of the water from the inlet pipe 4, after passing through the water replenishment hole 281, will flow back through the connecting water replenishment pipe 29 into the valve chamber 203 of the closed main pneumatic valve 25, replenishing the lower chamber of its valve piston 201. This design ensures that after the main pneumatic valve 25 completes one drainage cycle and closes, the lower chamber of its valve piston 201 can be quickly filled with water through this path, and the replenished water enters the chamber of the control piston 6 to balance the pressure. Rapid water replenishment speeds up the reset speed of the control piston 6, and the reset process is a flushing process, which significantly reduces the flushing time to save water.

[0030] To facilitate pneumatic control, the control valve body 20 also includes an airbag lifter 207. Both the small flush button 23 and the large flush button 21 have internal pressing airbags 234. The pressing airbags 234 are connected to the airbag lifter 207 via an air tube. The top of the airbag lifter 207 abuts against one end of the pressure rod 205. When the user presses the button, the pressing airbag 234 inside the button is compressed, and the resulting compressed air is instantly transmitted to the distal airbag lifter via the air tube. The airbag lifter 207 expands under air pressure, lifting the pressure rod 205 upwards, thereby triggering the aforementioned valve opening sequence. Pneumatic control achieves physical separation between the button and the valve body, allowing the button to be installed in a convenient location such as the toilet tank lid, while the valve body can be placed in an optimal position within the tank, offering high design flexibility. Furthermore, pneumatic transmission is more flexible than mechanical linkages and eliminates the risk of jamming.

[0031] The switching logic of the three-way connecting valve 22 is as follows: the three-way connecting valve 22 includes a three-way housing 221 and a switching sleeve 222. The connecting air pipes of the small exhaust button 23 and the large exhaust button 21 are respectively connected to the two ends of the three-way housing 221. An air outlet pipe 26 is provided on the side wall of the three-way housing 221, which is connected to the control end of the main pneumatic valve 25. The switching sleeve 222 is slidably connected in the three-way housing 221. Pressing the large exhaust button 21: airflow enters from the large exhaust button 21 end, pushing the switching sleeve 222 to slide towards the small exhaust button 23 end, blocking the channel of the small exhaust button 23, so that airflow can only flow out from the air outlet pipe 26 on the side wall, driving the main pneumatic valve 25. Pressing the small exhaust button 23: airflow enters from the small exhaust button 23 end, pushing the switching sleeve 222 to slide towards the large exhaust button 21 end, blocking the channel of the large exhaust button 21. At this time, the airflow from the small exhaust button 23 goes directly to the auxiliary pneumatic valve 24 on one hand, and flows out through the air outlet pipe 26 on the side wall through the cavity inside the three-way housing 221, driving the main pneumatic valve 25. The three-way connecting valve 22, as a mechanical pneumatic logic switch, perfectly realizes the complex control logic that the large exhaust button 21 only conducts the main circuit, while the small exhaust button 23 conducts both the main and auxiliary circuits through a simple sliding sleeve structure. It is the core hub of the entire dual-mode control system, and its design is extremely ingenious and effective.

[0032] 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.

[0033] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. The utility model 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 solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A dual-flow-control mechanical flushing valve, characterized in that: It includes a main pneumatic valve and an auxiliary pneumatic valve for connection with a control piston, a small discharge button, a large discharge button, and a three-way connecting valve; the large discharge button and the small discharge button are both connected to the three-way connecting valve, the outlet end of the three-way connecting valve is connected to the control end of the main pneumatic valve, and the small discharge button is connected to the control end of the auxiliary pneumatic valve; When the main pneumatic valve is pressed, the control piston drains water towards the main pneumatic valve until the main pneumatic valve closes, at which point the control piston returns to its original position under negative pressure. When the small drain button is pressed, the main pneumatic valve and the auxiliary pneumatic valve open simultaneously. The control piston drains water towards the main pneumatic valve until the main pneumatic valve closes. When the control piston is resetting due to negative pressure water intake, the auxiliary pneumatic valve replenishes water to it until the flushing is finished and the auxiliary pneumatic valve closes.

2. The dual-flow control mechanical flushing valve as described in claim 1, characterized in that: The auxiliary pneumatic valve includes a control valve body, a water supply pipe, and a water flow control rod. The water supply pipe is installed on the side wall of the water inlet pipe. The control valve body slides back and forth under the control of the small discharge button. One end of the water flow control rod is fixed to the control output end of the control valve body. A water supply hole is provided in the middle of the water supply pipe. The water flow control rod passes through the water supply hole and is connected to it with a gap. When the control valve body is opened, water from the inlet pipe enters the water supply pipe and passes through the gap between the water flow control rod and the water supply hole.

3. The dual-flow control mechanical flushing valve as described in claim 2, characterized in that: The control valve body includes a valve piston, a valve spring, and a valve cavity. The valve piston is slidably connected in the valve cavity. One end of the valve spring abuts against the valve piston. When started, the valve piston squeezes the valve spring under water pressure. When the pressure difference disappears, the valve spring resets its position.

4. The dual-flow control mechanical flushing valve as described in claim 3, characterized in that: The control valve body also includes a sealing cap, a pressure rod, and a pressure spring. An opening flow channel is provided on the side of the valve cavity where the valve spring is installed. In the initial state, the pressure rod squeezes the sealing cap under the action of the pressure spring, and the sealing cap blocks the opening flow channel. When the valve is opened, the pressure rod is raised, and the sealing cap is fixed in place under the action of water pressure until the water in the valve cavity is drained. Then, the sealing cap is reset and blocks the opening flow channel under the action of the compression spring.

5. The dual-flow control mechanical flushing valve as described in claim 4, characterized in that: The valve spring is provided with an extension guide rod that passes through the valve piston. When the valve piston is reset, the valve cavity is replenished with water through the gap between the extension guide rod and the valve piston to balance the negative pressure.

6. The dual-flow control mechanical flushing valve as described in claim 3, characterized in that: The main pneumatic valve includes the control valve body and a drain nozzle. The drain nozzle is installed at the end of the valve cavity of the control valve body. When it is not open, the valve piston blocks the channel between the drain nozzle and the water storage tank. When the main pneumatic valve is open, the valve cavity is connected to the water storage tank through the drain nozzle, and the control piston discharges water from the drain nozzle.

7. The dual-flow control mechanical flushing valve as described in claim 6, characterized in that: A connecting water supply pipe is provided between the drain nozzle and the water supply pipe. When the main pneumatic valve is closed, the water in the inlet pipe enters the valve chamber of the main pneumatic valve through the water supply hole to supply water to the control piston.

8. The dual-flow control mechanical flushing valve as described in claim 4, characterized in that: The control valve body also includes an airbag lifting part. Both the small and large drain buttons are equipped with pressing airbags. The pressing airbags are connected to the airbag lifting part. The top of the airbag lifting part abuts against one end of the pressure rod. When the small or large drain button is pressed, the airbag lifting part lifts one end of the pressure rod.

9. The dual-flow control mechanical flushing valve as described in claim 8, characterized in that: The three-way connecting valve includes a three-way housing and a switching sleeve. The small drain button and the large drain button are connected to both ends of the three-way housing. An air outlet pipe is provided on the side wall of the three-way housing. The switching sleeve is slidably connected in the three-way housing. Pressing the small drain button pushes the switching sleeve to slide to the other end, so that the small drain button is connected to the air outlet pipe.

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