Anti-backflow pressure reducing regulating valve with leakage protection

Abstract

This invention relates to the field of valve body technology; it proposes an anti-backflow pressure reducing regulating valve with leakage protection, comprising a main valve body, a main valve diaphragm, and a valve core assembly. The main valve body includes a valve cavity with an inlet end and an outlet end. The main valve diaphragm is disposed within the valve cavity and divides the valve cavity into a control cavity and a flow cavity. The pressure reducing regulating valve also includes a check valve core. The valve core assembly and the check valve core are sequentially disposed within the flow cavity, with an intermediate cavity between the valve core assembly and the check valve core. The valve core assembly is connected to the main valve diaphragm. The deformation of the main valve diaphragm controls the valve core assembly to open or close the flow cavity. The check valve core opens unidirectionally from the inlet end to the outlet end. The pressure reducing regulating valve also includes an anti-backflow reversing valve, a pressure reducing pilot valve, and a leakage protection valve. This technical solution solves the problem of maintaining the long-term reliability of anti-backflow valves in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of valve body technology, and more specifically, to an anti-backflow pressure reducing regulating valve with leakage protection. Background Technology

[0002] A pressure reducing valve is a valve that reduces the inlet pressure to a desired outlet pressure by adjustment, and automatically maintains a stable outlet pressure by relying on the energy of the medium itself.

[0003] Despite significant advancements in pressure-reducing valve technology, several challenges remain in practical applications. For instance, traditional pressure-reducing valves often continue to supply water even when dealing with large-scale drainage in case of downstream emergency leaks, leading to substantial water waste. Furthermore, they lack reliable backflow prevention when downstream pressure rises, especially in situations where downstream contamination is a concern. While some valves are designed with emergency shut-off functions, their reliability decreases with use due to deteriorating sealing. Therefore, a valve body capable of addressing these issues is urgently needed. Summary of the Invention

[0004] This invention proposes an anti-backflow pressure reducing regulating valve with leakage protection, which solves the problem that the reliability of valve anti-backflow is difficult to maintain for a long time in the prior art.

[0005] The technical solution of the present invention is as follows:

[0006] A backflow-preventing pressure-reducing regulating valve with leakage protection is disclosed. The pressure-reducing regulating valve includes a main valve body, a main valve diaphragm, and a valve core assembly. The main valve body includes a valve cavity with an inlet end and an outlet end. The main valve diaphragm is disposed within the valve cavity and divides the valve cavity into a control cavity and a flow cavity. The pressure-reducing regulating valve also includes a check valve core. The valve core assembly and the check valve core are sequentially disposed within the flow cavity, with an intermediate cavity between the valve core assembly and the check valve core. The valve core assembly is connected to the main valve diaphragm. The main valve diaphragm deforms to control the valve core assembly to open or close the flow cavity. The check valve core opens unidirectionally from the inlet end to the outlet end. The pressure-reducing regulating valve also includes an anti-backflow reversing valve, a pressure-reducing pilot valve, and a leakage protection valve. The inlet end, the anti-backflow reversing valve, the control cavity, the pressure-reducing pilot valve, and the outlet end are sequentially connected to enable the pressure-reducing regulating valve to be in a pressure-reducing dynamic adjustment state.

[0007] When the pressure reducing regulating valve is in the pressure reducing dynamic regulating state, the anti-backflow reversing valve switches to close the inlet end and the control chamber and connect the outlet end and the control chamber, so that the pressure reducing regulating valve switches to the emergency shut-off state and closes, and the check valve core closes in reverse.

[0008] When the pressure reducing regulating valve is in the emergency shut-off state, the venting protection valve selectively puts the intermediate chamber into a differential pressure protection state or a venting protection state based on the pressure difference between the intermediate chamber and the inlet end.

[0009] The anti-backflow reversing valve includes an anti-backflow port 1, an anti-backflow port 2, and an anti-backflow port 3. The pressure-reducing pilot valve includes a pilot valve port 1 and a pilot valve port 2. The pressure-reducing pilot valve includes a pilot valve body, a pilot valve diaphragm, a pre-tightening spring, and a pilot valve core. The pilot valve diaphragm divides the pilot valve body into a pressure-reducing chamber and a communicating chamber. The pilot valve core is connected to the pilot valve diaphragm. The pre-tightening spring is sleeved on the portion of the pilot valve core located in the pressure-reducing chamber. Both pilot valve port 1 and pilot valve port 2 are connected to the communicating chamber. When the pressure-reducing regulating valve is in a pressure-reducing dynamic adjustment state, anti-backflow port 1 is connected to the inlet end. The anti-backflow reversing valve connects anti-backflow port 2 and anti-backflow port 3 according to the pressure of anti-backflow port 1. The inlet end, anti-backflow port 2, anti-backflow port 3, control chamber, pilot valve port 1, pilot valve port 2, and outlet end can be connected sequentially.

[0010] The anti-backflow reversing valve also includes an anti-backflow port four and an anti-backflow port five. The anti-backflow port four is connected to the water outlet. The anti-backflow reversing valve selectively connects or shuts off the anti-backflow port three and the anti-backflow port five according to the pressure of the anti-backflow port four. The anti-backflow port five is connected to the water outlet.

[0011] The drain protection valve includes a connection port one, a connection port two, a connection port three, and a drain port. The drain protection valve includes a drain valve body, a drain valve core, and a drain spring. The connection port one is connected to the water inlet end. The connection ports two and three are both connected to the intermediate cavity. The connection ports one and three act on the two ends of the drain valve core, respectively. The drain spring is located at the end of the drain valve core near the connection port two. The drain valve core can move according to the pressure difference between the two ends to selectively connect the connection port two and the drain port.

[0012] The relief protection valve also includes an adjusting bolt, which is disposed on the relief valve housing, and the portion of the adjusting bolt located inside the relief valve housing abuts against the relief spring.

[0013] The check valve core includes a check bracket, a check spring, a check rod, and a check plate. The check bracket is disposed within the flow chamber. The check rod is movably disposed on the check bracket. The check plate is disposed on the check rod near the outlet end. The check spring is sleeved on the check rod, and the check spring causes the check rod to tend to move towards the inlet end. The movement of the check rod causes the check plate to open or close the flow chamber.

[0014] The anti-backflow reversing valve includes a reversing valve body and a reversing valve core, wherein the reversing valve core moves within the reversing valve body to switch the connection state.

[0015] The valve core assembly includes a valve stem and a valve plate. The valve stem is connected to the main valve diaphragm, and the valve plate is disposed in the portion of the valve stem located within the flow cavity.

[0016] The pressure reducing regulating valve also includes a regulating needle valve, and the anti-backflow reversing valve is connected to the control chamber via the regulating needle valve.

[0017] The working principle and beneficial effects of this invention are as follows:

[0018] This invention discloses an anti-backflow pressure reducing regulating valve with leakage protection. By setting an anti-backflow reversing valve, a leakage protection valve, and a pressure reducing pilot valve on the main valve body, after the pressure reducing regulating valve is opened, the connection state of each component is adjusted so that the entire valve body is in a dynamic pressure reducing regulating state. At this time, the valve body dynamically regulates the pressure between the inlet and outlet ends. When the pressure at the outlet end suddenly increases, and may be accompanied by water pollution, the check valve core closes in reverse and the connection state of each component is adjusted, so that the valve core assembly closes urgently. At this time, the reliability of anti-backflow is improved by the two anti-backflow designs. Based on this, considering the decay of the seal of the check valve core, the intermediate cavity also has the function of allowing the intermediate cavity to leak through the leakage protection valve. So even if the seal of the check valve core decays, the intermediate cavity can still leak, which plays a further role in anti-backflow protection. Based on the above solution, the problem of the difficulty in maintaining the long-term reliability of valve anti-backflow in the prior art can be solved. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram of the valve body in its initial state in this invention;

[0021] Figure 2 This is a schematic diagram of the valve body in the pressure reduction dynamic adjustment state in this invention;

[0022] Figure 3 This is a schematic diagram of the valve body in the closed and venting state in this invention.

[0023] In the diagram: 1. Main valve body, 2. Main valve diaphragm, 3. Inlet, 4. Outlet, 5. Control chamber, 6. Flow chamber, 7. Check valve core, 8. Intermediate chamber, 9. Anti-backflow directional valve, 10. Pressure reducing pilot valve, 11. Relief protection valve, 12. Anti-backflow port one, 13. Anti-backflow port two, 14. Anti-backflow port three, 15. Pilot valve port one, 16. Pilot valve port two, 17. Pilot valve body, 18. Pilot valve diaphragm, 19. Preload spring, 20. Pilot valve core, 21. Pressure reducing valve body. 21. Pressure chamber; 22. Connecting chamber; 23. Anti-backflow port four; 24. Anti-backflow port five; 25. Connection port one; 26. Connection port two; 27. Connection port three; 28. Drain port; 29. ​​Drain valve body; 30. Drain valve core; 31. Drain spring; 32. Adjusting bolt; 33. Check bracket; 34. Check spring; 35. Check rod; 36. Check plate; 37. Reversing valve body; 38. Reversing valve core; 39. Valve stem; 40. Valve plate; 41. Adjusting needle valve. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figures 1-3 As shown in the figure, this embodiment proposes an anti-backflow pressure reducing regulating valve with leakage protection. The pressure reducing regulating valve includes a main valve body 1, a main valve diaphragm 2, and a valve core assembly. The main valve body 1 includes a valve cavity with an inlet end 3 and an outlet end 4. The main valve diaphragm 2 is disposed in the valve cavity and divides the valve cavity into a control cavity 5 and a flow passage cavity 6. The pressure reducing regulating valve also includes a check valve core 7. The valve core assembly and the check valve core 7 are sequentially disposed in the flow passage cavity 6, with an intermediate cavity 8 between the valve core assembly and the check valve core 7. The valve core assembly is connected to the main valve diaphragm 2. The main valve diaphragm 2 deforms to control the valve core assembly to open or close the flow chamber 6. The check valve core 7 opens unidirectionally from the water inlet 3 to the water outlet 4. The pressure reducing regulating valve also includes an anti-backflow reversing valve 9, a pressure reducing pilot valve 10, and a leakage protection valve 11. The water inlet 3, the anti-backflow reversing valve 9, the control chamber 5, the pressure reducing pilot valve 10, and the water outlet 4 are sequentially connected to put the pressure reducing regulating valve in a pressure reducing dynamic regulating state.

[0026] When the pressure reducing regulating valve is in the pressure reducing dynamic adjustment state, the anti-backflow reversing valve 9 switches to close the inlet end 3 and the control chamber 5 and connects the outlet end 4 and the control chamber 5, so that the pressure reducing regulating valve switches to the emergency shut-off state and closes, and the check valve core 7 closes in reverse.

[0027] When the pressure reducing regulating valve is in the emergency shut-off state, the leakage protection valve 11 selectively puts the intermediate chamber 8 into a differential pressure protection state or a leakage protection state according to the pressure difference between the intermediate chamber 8 and the water inlet 3.

[0028] In this embodiment, the proposed anti-backflow pressure reducing regulating valve with leakage protection has a structure in which a valve cavity is set inside the main valve body 1. The valve cavity has an inlet end 3 and an outlet end 4. A main valve diaphragm 2 is set inside the valve cavity, dividing the valve cavity into a control cavity 5 and a flow cavity 6. The main valve diaphragm 2 is connected to the valve core assembly. The main valve diaphragm 2 deforms according to the pressure in the control cavity 5, thereby controlling the movement of the valve core assembly. The valve core assembly controls the opening and closing of the flow cavity 6. The main valve body 1 is also provided with a check valve core 7, an anti-backflow reversing valve 9, a leakage protection valve 11, and a pressure reducing pilot valve 10. Different connection states form different connection schemes, thereby making the entire pressure reducing regulating valve in a state of... Different states are used to deal with different scenarios. In the initial state of the pressure reducing regulating valve, the valve core assembly and the check valve core 7 are closed, the water pressure at the inlet 3 increases, and the water pressure reaches the outlet 4 through the anti-backflow reversing valve 9, the control chamber 5, and the pressure reducing pilot valve 10. The medium in the control chamber 5 flows to the outlet 4, so the water pressure is lower. At this time, the water pressure at the inlet 3 acts on the valve core assembly, so that the valve body opens. At the same time, the check valve core 7 opens, and the inlet 3 and the outlet 4 are connected. The pressure reducing pilot valve 10 senses the water pressure at the outlet 4, so as to fine-tune the opening amount, adjust the medium distribution flow in the control chamber 5, and then adjust the deformation of the main valve diaphragm 2 to achieve dynamic pressure reduction regulation.

[0029] When the water pressure at the outlet 4 surges and is accompanied by potential contamination, the anti-backflow reversing valve 9 adjusts and switches to disconnect the inlet 3 from the control chamber 5 and connect the outlet 4 to the control chamber 5. Due to the surge in pressure at the outlet 4, the main valve diaphragm 2 responds quickly and deforms under the pressure of the water at the outlet 4, and the valve core assembly closes. At the same time, the check valve core 7 also closes, thus putting the valve body into an emergency shut-off state.

[0030] Based on this, the valve core assembly and the check valve core 7 are closed, and the intermediate cavity 8 is a closed space. Considering the decay of sealing reliability, if the check valve core 7 leaks, causing the pressure in the intermediate cavity 8 to rise, the intermediate cavity 8 will be protected by the relief protection valve 11. According to the pressure difference between the intermediate cavity 8 and the inlet end 3, if the pressure difference between the intermediate cavity 8 and the inlet end 3 reaches a certain threshold, the intermediate cavity 8 will directly vent. If the threshold is not reached, the pressure value of the intermediate cavity 8 will always be less than the pressure value of the inlet end 3, that is, the medium in the intermediate cavity 8 will not flow back to the inlet end 3 side. The above can achieve backflow prevention protection.

[0031] It should be noted that the multiple auxiliary valves set up based on the technical concept of this application to achieve the functions of pressure reduction dynamic adjustment, emergency shutdown and backflow prevention, that is, to adjust the connection status of each auxiliary valve according to the pressure change of the inlet end 3 and the outlet end 4. If it is just a simple change in the valve body structure, quantity and connection method, it should fall within the protection scope of this application.

[0032] The anti-backflow reversing valve 9 includes an anti-backflow port 12, an anti-backflow port 23, and an anti-backflow port 34. The pressure-reducing pilot valve 10 includes a pilot valve port 15 and a pilot valve port 26. The pressure-reducing pilot valve 10 includes a pilot valve body 17, a pilot valve diaphragm 18, a preload spring 19, and a pilot valve core 20. The pilot valve diaphragm 18 divides the pilot valve body 17 into a pressure-reducing chamber 21 and a communicating chamber 22. The pilot valve core 20 is connected to the pilot valve diaphragm 18. The preload spring 19 is sleeved on the portion of the pilot valve core 20 located within the pressure-reducing chamber 21. Both pilot valve port 15 and pilot valve port 16 are connected to the connecting cavity 22. When the pressure reducing regulating valve is in the pressure reducing dynamic adjustment state, the anti-backflow port 12 is connected to the water inlet 3. The anti-backflow reversing valve 9 connects the anti-backflow port 13 and the anti-backflow port 34 according to the pressure of the anti-backflow port 12. The water inlet 3, the anti-backflow port 23, the anti-backflow port 34, the control cavity 5, the pilot valve port 15, the pilot valve port 16, and the water outlet 4 can be connected in sequence.

[0033] In this embodiment, the pressure reducing regulating valve is open and the inlet 3 and outlet 4 are in normal operating condition. The pressure reducing pilot valve 10 can sense the pressure at the outlet 4. Specifically, the anti-backflow reversing valve 9 is in one of the reversing positions through the medium pressure at the anti-backflow port 12, connecting the anti-backflow port 23 and the anti-backflow port 34. The medium pressure at the inlet 3 enters the control chamber 5 through the anti-backflow port 23 and the anti-backflow port 34. The medium pressure in the control chamber 5 can be connected to the pressure reducing pilot valve 10 through the pilot valve port 15, and the pilot valve port 216 is connected to the outlet 4. In the pressure reducing chamber 21 inside the pilot valve body 17, the pre-tensioning spring 19... The medium pressure at the outlet 4 is applied to the pilot valve diaphragm 18 through the pilot valve port 16. Initially, under the action of the pre-tightening spring 19, the pilot valve core 20 is in the open state. As the valve opens, the pressure at the outlet 4 increases. The pressure at the outlet 4 acts on the pilot valve diaphragm 18, causing the opening of the pressure reducing pilot valve 10 to decrease and maintain a dynamic adjustment state. When the pressure at the outlet 4 is less than the preset adjustment pressure value, the pre-tightening spring 19 causes the pilot valve core 20 to move and increase the opening. This increases the flow diversion in the control chamber 5, increases the opening of the valve core assembly control flow chamber 6, and increases the pressure compensation at the outlet 4. Conversely, the pilot valve core 20 decreases the opening.

[0034] The anti-backflow reversing valve 9 also includes an anti-backflow port 4 23 and an anti-backflow port 5 24. The anti-backflow port 4 23 is connected to the water outlet 4. The anti-backflow reversing valve 9 selectively connects or shuts off the anti-backflow port 3 14 and the anti-backflow port 5 24 according to the pressure of the anti-backflow port 4 23. The anti-backflow port 5 24 is connected to the water outlet 4.

[0035] In this embodiment, when the pressure at the outlet 4 suddenly increases, the anti-backflow port 23 of the anti-backflow reversing valve 9 senses the high pressure at the outlet 4. The anti-backflow reversing valve 9 then adjusts the connection state, closing the anti-backflow port 23 and the anti-backflow port 34, and connecting the anti-backflow port 34 with the anti-backflow port 524. The anti-backflow port 524 is connected to the outlet 4, and the high pressure at the outlet 4 enters the control chamber 5 through the anti-backflow port 524 and the anti-backflow port 314. The pressure in the control chamber 5 increases instantaneously, causing the pressure reducing regulating valve to close quickly and preventing backflow.

[0036] The drain protection valve 11 includes a first connection port 25, a second connection port 26, a third connection port 27, and a drain port 28. The drain protection valve 11 includes a drain valve body 29, a drain valve core 30, and a drain spring 31. The first connection port 25 is connected to the water inlet 3. The second connection port 26 and the third connection port 27 are both connected to the intermediate cavity 8. The first connection port 25 and the third connection port 27 act on the two ends of the drain valve core 30, respectively. The drain spring 31 is located at the end of the drain valve core 30 near the second connection port 26. The drain valve core 30 can move according to the pressure difference between the two ends to selectively connect the second connection port 26 and the drain port 28.

[0037] In this embodiment, the relief valve 11 provides pressure protection and relief protection for the intermediate cavity 8 by sensing the medium pressure at the inlet end 3 and the intermediate cavity 8. Specifically, the relief valve 11 senses the medium pressure at the inlet end 3 through connection port 1 25 and senses the medium pressure in the intermediate cavity 8 through connection port 3 27. The two ends of the relief valve core 30 sense the medium pressure at the inlet end 3 and the intermediate cavity 8, respectively. A relief spring 31 is also provided on the side near connection port 3 27. Therefore, the relief valve core 30 will only move when the medium pressure in the intermediate cavity 8 and the elastic force of the relief spring 31 are greater than the medium pressure at the inlet end 3. After the relief valve core 30 moves, connection port 2 26 and relief port 28 will then open. When the pressure reducing regulating valve is shut off due to backflow, the intermediate chamber 8 is closed by the valve core assembly and the check valve core 7. When the combined force of the medium pressure in the intermediate chamber 8 and the spring force of the relief spring 31 is still less than the medium pressure at the inlet end 3, the relief protection valve 11 keeps the pressure value in the intermediate chamber 8 at a lower protection value to prevent backflow to the inlet end 3 due to the decay of the sealing reliability of the valve core assembly. When the combined force of the medium pressure in the intermediate chamber 8 and the spring force of the relief spring 31 is greater than the medium pressure at the inlet end 3, the relief valve core 30 moves, connecting the second connection port 26 and the relief port 28, and the intermediate chamber 8 leaks and reduces pressure until the relief valve core 30 moves back to its original position, disconnecting the second connection port 26 and the relief port 28, thereby protecting the intermediate chamber 8 from backflow.

[0038] The relief protection valve 11 also includes an adjusting bolt 32, which is disposed on the relief valve housing 29. The portion of the adjusting bolt 32 located inside the relief valve housing 29 abuts against the relief spring 31.

[0039] In this embodiment, an adjusting bolt 32 is provided on the relief protection valve 11. The compression of the relief spring 31 is adjusted by rotating the adjusting bolt 32 to the depth of screwing into the relief valve housing 29, thereby adjusting the operating pressure difference between the intermediate chamber 8 and the water inlet 3. The so-called operating pressure difference means that when the operating pressure difference is exceeded, the relief valve core 30 will perform a switching action.

[0040] The check valve core 7 includes a check bracket 33, a check spring 34, a check rod 35, and a check plate 36. The check bracket 33 is disposed within the flow chamber 6. The check rod 35 is movably disposed on the check bracket 33. The check plate 36 is disposed on the check rod 35 near the outlet end 4. The check spring 34 is sleeved on the check rod 35. The check spring 34 causes the check rod 35 to tend to move towards the inlet end 3. The movement of the check rod 35 causes the check plate 36 to open or close the flow chamber 6.

[0041] In this embodiment, a check bracket 33 is provided in the flow cavity 6, and a check rod 35 passes through the middle of the check bracket 33. A check spring 34 is sleeved on the part of the check rod 35 that passes through the check bracket 33. When the check spring 34 is compressed, its elastic force causes the check rod 35 to tend to move towards the side closer to the water inlet end 3. The check plate 36 on the check rod 35 is on the side closer to the water outlet end 4. When the pressure changes from high to low along the direction from the water inlet end 3 to the water outlet end 4, the pressure of the medium acting on the check plate 36 overcomes the elastic force of the check spring 34, thus conducting. When the pressure at the water outlet end 4 increases, the check plate 36 closes under the action of the check spring 34, thus closing the flow cavity 6.

[0042] The anti-backflow reversing valve 9 includes a reversing valve housing 37 and a reversing valve core 38, wherein the reversing valve core 38 moves within the reversing valve housing 37 to switch the connection state.

[0043] In this embodiment, the anti-backflow reversing valve 9 adopts a structure in which a reversing valve core 38 is set inside the reversing valve housing 37. The reversing valve core 38 can be moved by the medium pressure, spring force or external pressing force to adjust the connection state and realize different working states of the pressure reducing regulating valve.

[0044] The valve core assembly includes a valve stem 39 and a valve plate 40. The valve stem 39 is connected to the main valve diaphragm 2, and the valve plate 40 is disposed in the portion of the valve stem 39 located within the flow cavity 6.

[0045] In this embodiment, the valve core assembly consists of a valve stem 39 and a valve plate 40. The valve stem 39 is connected to the main valve diaphragm 2. A guide structure that cooperates with the valve stem 39 is provided in the main valve body 1 so that the deformation of the main valve diaphragm 2 can drive the valve stem 39 to move. The end of the valve stem 39 is provided with a valve plate 40. The valve plate 40 can abut against and seal with the flow channel structure in the flow cavity 6 to realize the closure and opening of the flow channel.

[0046] The pressure reducing regulating valve also includes a regulating needle valve 41, and the anti-backflow reversing valve 9 is connected to the control chamber 5 via the regulating needle valve 41.

[0047] In this embodiment, the anti-backflow reversing valve 9 is connected to the control chamber 5 through the regulating needle valve 41. The regulating needle valve 41 consists of a needle valve body and a needle valve core. Rotating the needle valve core can adjust the opening of the regulating needle valve 41 and control the flow rate of the diverted flow.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A backflow-preventive pressure-reducing regulating valve with a leakage protection, characterized in that, The pressure reducing regulating valve includes a main valve body (1), a main valve diaphragm (2), and a valve core assembly. The main valve body (1) includes a valve cavity with an inlet end (3) and an outlet end (4). The main valve diaphragm (2) is disposed in the valve cavity and divides the valve cavity into a control cavity (5) and a flow cavity (6). The pressure reducing regulating valve also includes a check valve core (7). The valve core assembly and the check valve core (7) are sequentially disposed in the flow cavity (6). An intermediate cavity (8) is formed between the valve core assembly and the check valve core (7). The valve core assembly is connected to the main valve diaphragm (2). The main valve diaphragm (2) deforms to control the valve core assembly to open or close the flow cavity (6). The check valve core (7) opens unidirectionally from the inlet end (3) to the outlet end (4). The pressure reducing regulating valve also includes an anti-backflow reversing valve (9), a pressure reducing pilot valve (10), and a leakage protection valve (11). The inlet end (3), the anti-backflow reversing valve (9), the control chamber (5), the pressure reducing pilot valve (10), and the outlet end (4) are connected in sequence to put the pressure reducing regulating valve in a pressure reducing dynamic regulation state. The pressure reducing pilot valve (10) senses the water pressure at the outlet end (4), adjusts the medium flow rate in the control chamber (5), and then adjusts the deformation of the main valve diaphragm (2) to achieve pressure reducing dynamic regulation. When the pressure reducing regulating valve is in the pressure reducing dynamic regulating state, the anti-backflow reversing valve (9) switches to close the inlet end (3) and the control chamber (5) and connect the outlet end (4) and the control chamber (5) so that the pressure reducing regulating valve switches to the emergency shut-off state and closes, and the check valve core (7) closes in the reverse direction. When the pressure reducing regulating valve is in the emergency shut-off state, the leakage protection valve (11) selectively puts the intermediate chamber (8) into the differential pressure protection state or the leakage protection state according to the pressure difference between the intermediate chamber (8) and the water inlet (3); The drain protection valve (11) includes a first connection port (25), a second connection port (26), a third connection port (27), and a drain port (28). The drain protection valve (11) includes a drain valve body (29), a drain valve core (30), and a drain spring (31). The first connection port (25) is connected to the inlet end (3). The second connection port (26) and the third connection port (27) are both connected to the intermediate cavity (8). The first connection port (25) and the third connection port (27) act on the two ends of the drain valve core (30). The drain spring (31) is located at the end of the drain valve core (30) near the second connection port (26). The drain valve core (30) can move according to the pressure difference between the two ends so that the second connection port (26) and the drain port (28) can be selectively connected.

2. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 1, characterized in that, The anti-backflow reversing valve (9) includes an anti-backflow port one (12), an anti-backflow port two (13), and an anti-backflow port three (14). The pressure-reducing pilot valve (10) includes a pilot valve port one (15) and a pilot valve port two (16). The pressure-reducing pilot valve (10) includes a pilot valve body (17), a pilot valve diaphragm (18), a preload spring (19), and a pilot valve core (20). The pilot valve diaphragm (18) divides the pilot valve body (17) into a pressure-reducing chamber (21) and a connecting chamber (22). The pilot valve core (20) is connected to the pilot valve diaphragm (18). The preload spring (19) is sleeved on the pilot valve core (20) located in the pressure-reducing chamber (21). In the part inside, the pilot valve port one (15) and the pilot valve port two (16) are both connected to the connecting cavity (22). When the pressure reducing regulating valve is in the pressure reducing dynamic adjustment state, the anti-backflow port one (12) is connected to the water inlet (3). The anti-backflow reversing valve (9) connects the anti-backflow port two (13) and the anti-backflow port three (14) according to the pressure of the anti-backflow port one (12). The water inlet (3), the anti-backflow port two (13), the anti-backflow port three (14), the control cavity (5), the pilot valve port one (15), the pilot valve port two (16) and the water outlet (4) can be connected in sequence.

3. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 2, characterized in that, The anti-backflow reversing valve (9) also includes an anti-backflow port four (23) and an anti-backflow port five (24). The anti-backflow port four (23) is connected to the water outlet (4). The anti-backflow reversing valve (9) selectively connects or shuts off the anti-backflow port three (14) and the anti-backflow port five (24) according to the pressure of the anti-backflow port four (23). The anti-backflow port five (24) is connected to the water outlet (4).

4. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 1, characterized in that, The relief protection valve (11) also includes an adjusting bolt (32), which is disposed on the relief valve housing (29), and the portion of the adjusting bolt (32) located inside the relief valve housing (29) abuts against the relief spring (31).

5. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 3, characterized in that, The check valve core (7) includes a check bracket (33), a check spring (34), a check rod (35), and a check plate (36). The check bracket (33) is disposed in the flow chamber (6). The check rod (35) is movably disposed on the check bracket (33). The check plate (36) is disposed on the check rod (35) on the side near the outlet end (4). The check spring (34) is sleeved on the check rod (35). The check spring (34) causes the check rod (35) to have a tendency to move towards the inlet end (3). The movement of the check rod (35) causes the check plate (36) to open or close the flow chamber (6).

6. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 5, characterized in that, The anti-backflow reversing valve (9) includes a reversing valve housing (37) and a reversing valve core (38), wherein the reversing valve core (38) moves within the reversing valve housing (37) to switch the connection state.

7. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 6, characterized in that, The valve core assembly includes a valve stem (39) and a valve plate (40). The valve stem (39) is connected to the main valve diaphragm (2), and the valve plate (40) is disposed on the portion of the valve stem (39) located in the flow cavity (6).

8. The anti-backflow pressure reducing regulating valve with leakage protection according to claim 7, characterized in that, The pressure reducing regulating valve also includes a regulating needle valve (41), and the anti-backflow reversing valve (9) is connected to the control chamber (5) via the regulating needle valve (41).

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