A pilot operated safety valve

Abstract

The application discloses a pilot safety valve and relates to the technical field of safety valves. The pilot safety valve comprises a main valve mechanism, a pilot valve mechanism and a connecting assembly. The main valve mechanism and the connecting assembly are in pipeline communication. The pilot valve mechanism comprises a pilot valve seat, a pilot valve cover and a pilot valve core. The pilot valve cover is arranged on the pilot valve seat. The pilot valve core penetrates through the bottom of the pilot valve cover. The pilot valve seat is internally provided with an exhaust hole and a connecting hole. One end of the connecting hole is in pipeline communication with the exhaust hole. The pilot valve cover is internally provided with a spring cavity. The pilot valve seat and the connecting assembly are in pipeline communication. The connecting hole is internally provided with a balance pipe. The pilot valve core is inserted into the spring cavity. One end of the balance pipe is inserted into the exhaust hole. The other end of the balance pipe is inserted into the spring cavity. The balance pipe is used for balancing the pressure on both sides of the pilot valve core. The application balances the pressure difference on both sides of the pilot valve core through the coordinated structure of the balance pipe and the metal wire arranged in the pilot valve mechanism, thereby shortening the reseating time of the pilot valve core.

Description

Technical Field

[0001] This invention relates to the field of safety valve technology, specifically a pilot-operated safety valve. Background Technology

[0002] Pilot-operated safety valves, as precision overpressure protection devices, are widely used in key industrial fields such as petroleum, chemical, and nuclear power. Their basic structure consists of two parts: a main valve and a pilot valve. The pilot valve senses the pressure of the medium and controls the opening and closing of the main valve. Current pilot-operated safety valve designs primarily focus on sealing performance, opening accuracy, and reseating reliability. They typically employ a spring-loaded pilot valve core and a piston-type main valve structure, connected via a pressure-conducting pipe.

[0003] In existing pilot-operated safety valves, the pilot valve discharge port is typically directly connected to the discharge pipeline, directing the discharged medium to a safe area. However, in actual operation, it has been found that when the pilot valve completes its discharge action and attempts to reseat and close, delayed reseating or even failure to reseat often occurs, leading to continuous discharge of the medium. Furthermore, in applications handling waxy, coking, or high-viscosity media, the main valve piston of pilot-operated safety valves often experiences problems such as motion stagnation, slow opening, or even complete jamming and failure after prolonged operation. Summary of the Invention

[0004] The purpose of this invention is to provide a pilot-operated safety valve to solve the problems of delayed pilot valve reseating and slow main valve piston opening in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A pilot-operated safety valve includes a main valve mechanism, a pilot valve mechanism, and a connecting assembly, wherein the main valve mechanism and the connecting assembly are connected by pipelines. The pilot valve mechanism includes a pilot valve seat, a pilot valve cover, and a pilot valve core. The pilot valve seat is provided with a pilot valve cover, and the pilot valve core passes through the bottom of the pilot valve cover. The pilot valve seat has an exhaust port and a connection port inside, and one end of the connection port is connected to the exhaust port pipe; The pilot valve cover has a spring cavity inside; The pilot valve seat and the connecting assembly are connected by a pipeline. A balance tube is provided inside the connecting hole. The pilot valve core is inserted into the spring cavity. One end of the balance tube is inserted into the vent hole, and the other end of the balance tube is inserted into the spring cavity. The balance tube is used to balance the pressure on both sides of the pilot valve core.

[0006] The flowing medium enters from the main valve mechanism and then passes through the connecting assembly into the pilot valve mechanism. The connecting assembly connects to the corresponding channels of both the main valve mechanism and the pilot valve mechanism, ensuring accurate and rapid transmission of medium pressure. This allows for precise opening and closing of the main valve. When the pressure of the flowing medium in the main pipeline is less than the set pressure of the pilot valve mechanism, the main valve mechanism is closed, and the flowing medium is normally transported within the main pipeline. When the pressure of the flowing medium in the main pipeline exceeds the set pressure of the pilot valve mechanism, the pilot valve core moves upward, closing the transport path from the pilot valve mechanism to the main valve mechanism and discharging the flowing medium through the vent. When the main valve mechanism is in the open state, the flowing medium in the main pipeline is discharged, releasing the pressure in the pipeline. When the exhaust port forms a momentary negative pressure due to gas inertia, one end of the balance tube immediately senses the negative pressure, and the other end draws gas from the spring chamber to replenish the exhaust channel. This process is completed in a short time, effectively neutralizing the local negative pressure in the exhaust port and eliminating the reverse suction force acting on the front of the pilot valve core, allowing the pilot valve core to be pushed back to its seat. The inner diameter and length of the balance tube can be precisely designed according to the discharge flow characteristics of different specifications of pilot valves to achieve the best matching of the pumping rate, with extremely high reliability and maintenance-free characteristics.

[0007] Furthermore, a metal wire is installed inside the balance tube. One end of the metal wire is fixed to the balance tube and is close to the valve cover of the pilot valve, while the other end of the metal wire is close to the exhaust port.

[0008] The metal wire installed inside the balance tube has its fixed end near the pilot valve cover and its other end near the vent. This design further optimizes the pressure balance, reduces the resistance of the pilot valve core during operation, and improves its response speed and reseating accuracy. The metal wire is made of a high-strength and corrosion-resistant material to ensure that it will not break due to media corrosion or frequent operation during long-term use. During the pilot valve core's operation, the metal wire effectively guides the flow of the medium, preventing the formation of eddies within the balance tube, thereby reducing energy loss and pressure fluctuations. When the pilot valve core reseats, the metal wire quickly transmits the pressure change near the vent to the other end of the balance tube, accelerating the pressure balance process and further improving the response speed and reseating accuracy of the pilot valve mechanism.

[0009] Furthermore, the connecting assembly includes a pressure guiding pipe and a return pipe, with both ends of the pressure guiding pipe connected to the pipeline and both ends of the return pipe connected to the pipeline. The pilot valve seat also includes a pressure guiding hole and a return hole; The two ends of the pressure guiding pipe are connected to the pressure guiding hole and the main valve mechanism pipeline, respectively, and the two ends of the return pipe are connected to the return hole and the main valve mechanism pipeline, respectively.

[0010] The pressure-conducting pipe and the return pipe constitute the key channels for the transmission and return of medium pressure. The pressure-conducting pipe accurately transmits the medium pressure in the main pipeline to the pilot valve mechanism, ensuring that the pilot valve mechanism can act in a timely manner according to the actual pressure. When the pressure in the main pipeline exceeds the set value, the pressure-conducting pipe transmits a high-pressure signal to the pilot valve mechanism, triggering the pilot valve mechanism to open and discharge the medium. The return pipe is responsible for returning the medium remaining during the closing process of the main valve mechanism back to the system, preventing the medium from accumulating inside the main valve mechanism. Through the precise connection between the pressure-conducting hole and the return hole and the main valve mechanism, closed-loop control of the medium pressure is realized, improving the stability and reliability of the entire safety valve system.

[0011] Furthermore, the pilot valve mechanism also includes a transition assembly, which is slidably connected to the pilot valve core; The pilot valve seat also includes a transition chamber and an inlet chamber. A through hole is provided between the transition chamber and the inlet chamber. The transition chamber is connected to the exhaust hole and the return hole pipe respectively, and the inlet chamber is connected to the pressure guide hole pipe. The transition cavity is equipped with a transition component.

[0012] The transition component plays a crucial role in the pilot valve mechanism. Through its sliding connection with the pilot valve core, it ensures smooth flow of the medium within the pilot valve. After entering the inlet chamber from the pressure-conducting port, the medium flows through the through-hole into the transition chamber, and then from the transition chamber to the exhaust port and return port. The presence of the transition component reduces pressure loss and fluctuations during medium flow, thereby improving the operational stability of the pilot valve. Furthermore, the design of the transition component takes into account the characteristics of the medium and operating conditions, ensuring that the pilot valve mechanism functions normally under different media and pressure conditions, effectively preventing problems such as pilot valve reseating delay and slow opening of the main valve piston.

[0013] Furthermore, the pilot valve core includes an upper valve core, a middle valve core, and a lower valve core, which are arranged sequentially from top to bottom; The transition component has a transfer cavity and a transfer hole inside, and the transfer cavity and the transfer hole are connected by pipes; The upper valve core is inserted into the spring cavity, the middle valve core passes through the through hole, and the lower valve core is inserted into the transmission cavity. The transmission hole and the exhaust hole are connected.

[0014] This segmented design of the pilot valve core, combined with the special structure of the transition component, enables precise control and smooth flow of the medium within the pilot valve. The upper valve core, within the spring chamber, is subjected to the force of the pilot valve spring, allowing it to respond promptly to pressure changes in the medium within the main pipeline. As the middle valve core passes through the through-hole, its cooperation with the transition component ensures a stable transition of the medium between the inlet and transition chambers, reducing pressure shocks and fluctuations. The lower valve core inserts into the transmission chamber and connects to the vent hole through the transmission hole, allowing the medium to be quickly discharged through the vent hole when the pressure in the main pipeline exceeds the set value, thereby opening the main valve.

[0015] Furthermore, the lower valve core is provided with a transmission hole, which is connected to the transition chamber and the transmission chamber pipes respectively.

[0016] The design of the transmission hole allows the medium to form a continuous flow channel inside the pilot valve core, avoiding dead zones or stagnation during the flow process, thus effectively preventing valve core jamming caused by medium crystallization, deposition, etc.

[0017] Furthermore, the pilot valve mechanism also includes a pilot valve spring and an adjusting screw. The adjusting screw is inserted into the spring cavity, and the lower end of the adjusting screw is provided with a pilot valve spring. The upper valve core is provided below the pilot valve spring.

[0018] The combined design of the pilot valve spring and adjusting screw provides the pilot valve mechanism with flexible pressure regulation. By rotating the adjusting screw, the preload of the pilot valve spring can be precisely changed, thereby adjusting the opening pressure setting of the pilot valve mechanism. This design allows the pilot-operated safety valve to adapt to pressure protection requirements under different operating conditions. Precise setting of the opening pressure can be achieved simply by adjusting the position of the adjusting screw, without replacing the entire pilot valve mechanism, greatly improving the applicability and maintenance convenience of the equipment. The pilot valve spring is made of high-strength, corrosion-resistant materials, ensuring that it will not lose its elasticity due to media corrosion or frequent operation during long-term use, guaranteeing the reliability and stability of the pilot valve mechanism. Under the action of the pilot valve spring, the upper valve core can respond promptly to pressure changes in the main pipeline. When the pressure exceeds the set value, the upper valve core overcomes the spring force and moves upward, triggering the pilot valve mechanism to open and discharge the media, thereby realizing the opening of the main valve and pressure release.

[0019] Furthermore, the main valve mechanism includes a main valve body, a main valve seat, a piston, a main valve spring, and a main valve cover. The main valve body and the piston are slidably connected. The main valve spring is located below the main valve cover, and the piston is located below the main valve spring. The upper end of the main valve seat and the lower end of the piston abut against each other.

[0020] The main valve body, as the fundamental supporting component of the entire main valve mechanism, has a rational and robust structural design, capable of withstanding various forces generated by the medium during flow. The main valve seat and the lower end of the piston are tightly abutted together; the sealing design between them is meticulously considered, employing high-precision machining processes and high-quality sealing materials to effectively prevent medium leakage when the main valve is closed, ensuring safe system operation. The piston slides within the main valve body, featuring a smooth surface and good wear resistance, reducing frictional resistance with the main valve body, lowering energy loss, and improving the flexibility and stability of piston movement. The main valve spring is installed below the main valve cover between it and the piston, providing a reset force for the piston. The main valve cover protects the internal components of the main valve and seals the main valve mechanism; it is reliably connected to the main valve body, forming a closed working space to prevent external impurities from entering the main valve and affecting its normal operation.

[0021] Furthermore, the main valve body includes an inlet and an outlet; The piston has several sets of guide grooves on its upper outer ring; The main valve cover includes a reflux port; The inlet is equipped with a main valve seat at the upper end, and the inlet is connected to the pressure guide pipe, while the return port is connected to the return pipe.

[0022] The inlet and outlet ports inside the main valve body serve as channels for the medium to flow in and out, respectively. The main valve seat, located above the inlet, fits tightly with the lower end of the piston, forming a reliable sealing structure that effectively prevents leakage of the medium when the main valve is closed. Several sets of guide grooves on the outer ring of the upper end of the piston not only guide the flow of the medium and reduce the impact force of the medium on the piston, but also reduce the frictional resistance during piston movement, extending the service life of the main valve. The return port on the main valve cover is connected to the return pipe. After the medium enters, it induces local eddies at the guide grooves. These eddies effectively break the boundary layer on the piston surface, carrying away depositing impurity particles, achieving a self-cleaning effect without any external flushing medium. This also allows the main valve mechanism to quickly discharge residual medium back into the system during the closing process, preventing the accumulation and crystallization of the medium inside the main valve mechanism, further improving the reliability and safety of the main valve.

[0023] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention effectively balances the pressure difference on both sides of the pilot valve core by setting a synergistic structure of a balance tube and a metal wire inside the pilot valve mechanism, thereby shortening the pilot valve core reseating time; 2. In this invention, the main valve mechanism adopts a design with a guide groove and multiple pipelines. After the medium enters, a local vortex is generated at the guide groove. This vortex can effectively destroy the boundary layer on the piston surface and carry away the impurity particles that are being deposited, thus achieving a self-cleaning effect. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the pilot valve mechanism of the present invention; Figure 3 for Figure 2 A magnified view of part A of the view; Figure 4 for Figure 2 A magnified view of part B in the view; Figure 5 This is a schematic diagram of the structure of the pilot valve mechanism and connecting assembly of the present invention; Figure 6 for Figure 5 A magnified view at point C in the view; Figure 7 This is a schematic diagram of the main valve mechanism of the present invention; Figure 8 for Figure 7 A magnified view at point D in the view.

[0025] In the diagram: 1. Main valve mechanism; 11. Main valve body; 111. Inlet; 112. Outlet; 12. Main valve seat; 13. Piston; 131. Guide groove; 14. Main valve spring; 15. Main valve cover; 151. Return port; 2. Pilot valve mechanism; 21. Pilot valve seat; 211. Exhaust port; 212. Connection hole; 213. Pressure guide hole; 214. Return hole; 215. Transition chamber; 216. Inlet 217. Through hole; 22. Pilot valve cover; 221. Spring cavity; 23. Pilot valve core; 231. Upper valve core; 232. Middle valve core; 233. Lower valve core; 2331. Transmission hole; 24. Balance tube; 25. Metal wire; 26. Transition assembly; 261. Transmission cavity; 262. Transmission hole; 27. Pilot valve spring; 28. Adjusting screw; 3. Connecting assembly; 31. Pressure guide tube; 32. Return tube. Detailed Implementation

[0026] 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, and 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.

[0027] Example: Figures 1-8 As shown, the present invention provides a technical solution: a pilot-operated safety valve.

[0028] like Figures 1-2As shown, a pilot-operated safety valve includes a main valve mechanism 1, a pilot valve mechanism 2, and a connecting assembly 3, with the main valve mechanism 1 and the connecting assembly 3 connected by pipelines. The pilot valve mechanism 2 includes a pilot valve seat 21, a pilot valve cover 22, and a pilot valve core 23. The pilot valve seat 21 is provided with the pilot valve cover 22, and the pilot valve core 23 passes through the bottom of the pilot valve cover 22. The pilot valve seat 21 is provided with an exhaust hole 211 and a connection hole 212 inside, and one end of the connection hole 212 is connected to the exhaust hole 211 via a pipe. The pilot valve cover 22 has a spring cavity 221 inside; The pilot valve seat 21 and the connecting assembly 3 are connected by a pipeline. The connecting hole 212 is provided with a balance tube 24. The pilot valve core 23 is inserted into the spring cavity 221. One end of the balance tube 24 is inserted into the exhaust hole 211, and the other end of the balance tube 24 is inserted into the spring cavity 221. The balance tube 24 is used to balance the pressure on both sides of the pilot valve core 23.

[0029] The flowing medium enters from the main valve mechanism 1 and passes through the connecting assembly 3 into the pilot valve mechanism 2. The connecting assembly 3 is connected to the corresponding channels of the main valve mechanism 1 and the pilot valve mechanism 2, ensuring that the medium pressure can be transmitted accurately and quickly, thereby realizing the precise opening and closing of the main valve. When the pressure of the flowing medium in the main pipeline is less than the set pressure of the pilot valve mechanism 2, the main valve mechanism 1 is in the closed state, and the flowing medium is normally transported in the main pipeline. When the pressure of the flowing medium in the main pipeline is greater than the set pressure of the pilot valve mechanism 2, the pilot valve core 23 moves upward, closing the transport path from the pilot valve mechanism 2 to the main valve mechanism 1, and discharging the flowing medium from the vent 211, thus... The main valve mechanism 1 is in the open state, thereby discharging the flowing medium in the main pipeline and releasing the pressure in the pipeline. When the exhaust port 211 forms an instantaneous negative pressure due to gas inertia, one end of the balance tube 24 immediately senses the negative pressure, and the other end draws gas from the spring chamber 221 to replenish the discharge channel. This process is completed in a short time, effectively neutralizing the local negative pressure of the exhaust port 211 and eliminating the reverse suction force acting on the front of the pilot valve core 23, so that the pilot valve core 23 can be pushed back to its seat. The inner diameter and length of the balance tube 24 can be precisely designed according to the discharge flow characteristics of different specifications of pilot valves to achieve the best air pumping rate matching, with extremely high reliability and maintenance-free characteristics.

[0030] like Figures 2-3 As shown, a metal wire 25 is provided inside the balance tube 24. One end of the metal wire 25 is fixed to the balance tube 24 and is close to the valve cover 22 of the pilot valve, while the other end of the metal wire 25 is close to the exhaust port 211.

[0031] The metal wire 25 installed inside the balance tube 24 has its fixed end near the pilot valve cover 22 and its other end near the exhaust port 211. This design further optimizes the pressure balance effect, reduces the resistance of the pilot valve core 23 during operation, and improves its response speed and reseating accuracy. The metal wire 25 is made of a high-strength and corrosion-resistant material to ensure that it will not break due to media corrosion or frequent operation during long-term use. When the pilot valve core 23 is operating, the metal wire 25 can effectively guide the flow direction of the medium, preventing the medium from forming eddies in the balance tube 24, thereby reducing energy loss and pressure fluctuations. When the pilot valve core 23 reseats, the metal wire 25 can quickly transmit the pressure change near the exhaust port 211 to the other end of the balance tube 24, accelerating the pressure balance process and further improving the response speed and reseating accuracy of the pilot valve mechanism 2.

[0032] like Figure 5 As shown, the connecting component 3 includes a pressure guiding pipe 31 and a return pipe 32. Both ends of the pressure guiding pipe 31 are connected to the pipeline, and both ends of the return pipe 32 are connected to the pipeline. The valve seat 21 of the pilot valve also includes a pressure guiding hole 213 and a return hole 214; The two ends of the pressure guiding pipe 31 are connected to the pressure guiding hole 213 and the main valve mechanism 1 pipeline, respectively, and the two ends of the return pipe 32 are connected to the return hole 214 and the main valve mechanism 1 pipeline, respectively.

[0033] The pressure-conducting pipe 31 and the return pipe 32 constitute the key channels for the transmission and return of medium pressure. The pressure-conducting pipe 31 accurately transmits the medium pressure in the main pipeline to the pilot valve mechanism 2, ensuring that the pilot valve mechanism 2 can act in a timely manner according to the actual pressure. When the pressure in the main pipeline exceeds the set value, the pressure-conducting pipe 31 transmits a high-pressure signal to the pilot valve mechanism 2, triggering the pilot valve mechanism 2 to open and discharge the medium. The return pipe 32 is responsible for returning the medium remaining in the main valve mechanism 1 during the closing process to the system, preventing the medium from accumulating inside the main valve mechanism 1. Through the precise connection with the main valve mechanism 1 via the pressure-conducting hole 213 and the return hole 214, closed-loop control of the medium pressure is realized, improving the stability and reliability of the entire safety valve system.

[0034] like Figure 4 As shown, the pilot valve mechanism 2 also includes a transition component 26, which is slidably connected to the pilot valve core 23; The valve seat 21 of the pilot valve also includes a transition chamber 215 and an inlet chamber 216. A through hole 217 is provided between the transition chamber 215 and the inlet chamber 216. The transition chamber 215 is connected to the exhaust hole 211 and the return hole 214 respectively, and the inlet chamber 216 is connected to the pressure guide hole 213. The transition cavity 215 is equipped with a transition component 26.

[0035] The transition component 26 plays a crucial role in the pilot valve mechanism 2. Through its sliding connection with the pilot valve core 23, it enables smooth flow of the medium within the pilot valve. After the medium enters the inlet chamber 216 through the pressure guide hole 213, it flows into the transition chamber 215 through the through hole 217, and then flows from the transition chamber 215 to the exhaust hole 211 and the return hole 214. The presence of the transition component 26 reduces pressure loss and fluctuations during medium flow, thereby improving the operational stability of the pilot valve. Furthermore, the design of the transition component 26 takes into account the characteristics of the medium and operating conditions, ensuring that the pilot valve mechanism 2 can operate normally under different medium and pressure conditions, effectively preventing problems such as pilot valve reseating delay and slow opening of the main valve piston 13.

[0036] like Figures 5-6 As shown, the pilot valve core 23 includes an upper valve core 231, a middle valve core 232, and a lower valve core 233, which are arranged sequentially from top to bottom; The transition component 26 has a transfer cavity 261 and a transfer hole 262 inside, and the transfer cavity 261 and the transfer hole 262 are connected by pipes; The upper valve core 231 is inserted into the spring cavity 221, the middle valve core 232 passes through the through hole 217, and the lower valve core 233 is inserted into the transmission cavity 261. The transmission hole 262 and the exhaust hole 211 are connected by pipes.

[0037] This segmented design of the pilot valve core 23, combined with the special structure of the transition component 26, enables precise control and smooth flow of the medium within the pilot valve. The upper valve core 231, within the spring chamber 221, is subjected to the force of the pilot valve spring 27, allowing it to respond promptly to pressure changes in the medium within the main pipeline. When the middle valve core 232 passes through the through hole 217, its cooperation with the transition component 26 ensures a stable transition of the medium between the inlet chamber 216 and the transition chamber 215, reducing pressure shocks and fluctuations. The lower valve core 233 is inserted into the transmission chamber 261 and connected to the vent hole 211 through the transmission hole 262, allowing the medium to be quickly discharged through the vent hole 211 when the pressure in the main pipeline exceeds the set value, thereby opening the main valve.

[0038] like Figure 6 As shown, the lower valve core 233 has a transmission hole 2331 inside, which is connected to the transition chamber 215 and the transmission chamber 261 respectively.

[0039] The design of the transmission port 2331 enables the medium to form a continuous flow channel inside the pilot valve core 23, avoiding dead zones or stagnation during the flow process, thereby effectively preventing valve core jamming caused by medium crystallization, deposition, etc.

[0040] like Figures 1-2As shown, the pilot valve mechanism 2 also includes a pilot valve spring 27 and an adjusting screw 28. The adjusting screw 28 is inserted into the spring cavity 221. The lower end of the adjusting screw 28 is provided with the pilot valve spring 27, and the upper valve core 231 is provided below the pilot valve spring 27.

[0041] The combined design of the pilot valve spring 27 and the adjusting screw 28 provides the pilot valve mechanism 2 with flexible pressure regulation. By rotating the adjusting screw 28, the preload of the pilot valve spring 27 can be precisely changed, thereby adjusting the opening pressure setting value of the pilot valve mechanism 2. This design allows the pilot-operated safety valve to adapt to the pressure protection requirements under different working conditions. The precise setting of the opening pressure can be achieved simply by adjusting the position of the adjusting screw 28, without replacing the entire pilot valve mechanism 2, greatly improving the applicability and maintenance convenience of the equipment. The pilot valve spring 27 is made of high-strength, corrosion-resistant materials, ensuring that it will not lose its elasticity due to medium corrosion or frequent operation during long-term use, guaranteeing the reliability and stability of the pilot valve mechanism 2. Under the action of the pilot valve spring 27, the upper valve core 231 can respond promptly to pressure changes in the medium in the main pipeline. When the pressure exceeds the set value, the upper valve core 231 overcomes the spring force and moves upward, triggering the pilot valve mechanism 2 to open and discharge the medium, thereby realizing the opening of the main valve and pressure release.

[0042] like Figure 7 As shown, the main valve mechanism 1 includes a main valve body 11, a main valve seat 12, a piston 13, a main valve spring 14, and a main valve cover 15. The main valve body 11 and the piston 13 are slidably connected. The main valve spring 14 is located below the main valve cover 15, and the piston 13 is located below the main valve spring 14. The upper end of the main valve seat 12 and the lower end of the piston 13 abut against each other.

[0043] The main valve body 11, as the fundamental supporting component of the entire main valve mechanism 1, has a reasonable and robust structural design, capable of withstanding various forces generated by the medium during flow. The main valve seat 12 is tightly abutted against the lower end of the piston 13. The sealing design between them has been carefully considered, employing high-precision machining technology and high-quality sealing materials to ensure effective prevention of medium leakage when the main valve is closed, guaranteeing the safe operation of the system. The piston 13 is slidably connected within the main valve body 11, featuring a smooth surface and good wear resistance, reducing frictional resistance with the main valve body 11, lowering energy loss, and improving the flexibility and stability of piston 13 movement. The main valve spring 14 is installed below the main valve cover 15 between itself and the piston 13, providing a reset force for the piston 13. The main valve cover 15 protects the internal components of the main valve and seals the main valve mechanism 1. It is reliably connected to the main valve body 11, forming a closed working space to prevent external impurities from entering the main valve and affecting its normal operation.

[0044] like Figures 7-8As shown, the main valve body 11 includes an inlet 111 and an outlet 112. The piston 13 has several sets of guide grooves 131 on the outer ring at the upper end; The main valve cover 15 includes a return port 151; The inlet 111 is equipped with a main valve seat 12 at its upper end. The inlet 111 is connected to the pressure guide pipe 31, and the return port 151 is connected to the return pipe 32.

[0045] The inlet 111 and outlet 112 inside the main valve body 11 serve as channels for the medium to flow in and out, respectively. The main valve seat 12, located at the upper end of the inlet 111, fits tightly with the lower end of the piston 13, forming a reliable sealing structure that effectively prevents leakage of the medium when the main valve is closed. Several sets of guide grooves 131 on the outer ring of the upper end of the piston 13 not only guide the flow of the medium and reduce the impact force of the medium on the piston 13, but also reduce the frictional resistance of the piston 13 during movement, extending the service life of the main valve. The return port 151 on the main valve cover 15 is connected to the return pipe 32. After the medium enters, a local vortex is induced at the guide groove 131. This vortex can effectively break the boundary layer on the surface of the piston 13, carrying away the depositing impurity particles, achieving a self-cleaning effect without any external flushing medium. It also allows the main valve mechanism 1 to quickly discharge the residual medium back to the system during the closing process, avoiding the accumulation and crystallization of the medium inside the main valve mechanism 1, further improving the reliability and safety of the main valve.

[0046] Working principle of the invention: When the system is running normally, the pressure of the medium in the main pipeline is less than the set pressure of the pilot valve mechanism 2. The pilot valve core 23 is in the initial position. The medium enters through the inlet 111 of the main valve mechanism 1, passes through the sealing area between the main valve seat 12 and the piston 13, and flows out normally from the outlet 112. It is transported in the main pipeline, forming a stable pressure balance state. When the pressure of the medium flowing in the main pipeline gradually increases and exceeds the set pressure of the pilot valve mechanism 2, the pressure of the medium in the inlet chamber 216 increases, pushing the pilot valve core 23 to move upward against the preload of the pilot valve spring 27. The lower valve core 233 gradually disengages from the transmission chamber 261, closing the transmission path from the pilot valve mechanism 2 to the main valve mechanism 1. The medium is quickly discharged through the transmission hole 262 and the exhaust hole 211, causing the pressure at the upper end of the piston 13 of the main valve mechanism 1 to decrease.

[0047] During the exhaust process, when the exhaust port 211 forms a momentary negative pressure due to gas inertia, one end of the balance tube 24 immediately senses the negative pressure, and the other end draws gas from the spring chamber 221 to replenish the exhaust channel. This process is completed in a short time, effectively neutralizing the local negative pressure of the exhaust port 211 and eliminating the reverse suction force acting on the front of the pilot valve core 23. This allows the pilot valve core 23 to be pushed back to its seat under the action of the pilot valve spring 27. Furthermore, the metal wire 25 installed inside the balance tube 24 can effectively guide the flow direction of the medium during the operation of the pilot valve core 23, preventing the medium from forming eddies in the balance tube 24 and reducing energy loss and pressure fluctuations.

[0048] When the pressure in the main pipeline drops below the set value, the pilot valve core 23 returns to its initial position under the action of the pilot valve spring 27, and the piston 13 of the main valve mechanism 1 moves downward under the action of the main valve spring 14, closing the main valve mechanism 1 and restoring the system to normal operation.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A pilot-operated safety valve, characterized in that: The pilot-operated safety valve includes a main valve mechanism (1), a pilot valve mechanism (2), and a connecting assembly (3), wherein the main valve mechanism (1) and the connecting assembly (3) are connected by a pipeline; The pilot valve mechanism (2) includes a pilot valve seat (21), a pilot valve cover (22) and a pilot valve core (23). The pilot valve seat (21) is provided with a pilot valve cover (22), and the pilot valve core (23) passes through the bottom of the pilot valve cover (22). The valve seat (21) of the pilot valve is provided with an exhaust hole (211) and a connection hole (212) inside, and one end of the connection hole (212) is connected to the exhaust hole (211) through a pipe; The valve cover (22) of the pilot valve is provided with a spring cavity (221). The pilot valve seat (21) and the connecting assembly (3) are connected by a pipe. The connecting hole (212) is provided with a balance tube (24). The pilot valve core (23) is inserted into the spring cavity (221). One end of the balance tube (24) is inserted into the exhaust hole (211), and the other end of the balance tube (24) is inserted into the spring cavity (221). The balance tube (24) is used to balance the pressure on both sides of the pilot valve core (23).

2. The pilot-operated safety valve according to claim 1, characterized in that: The balance tube (24) is provided with a metal wire (25). One end of the metal wire (25) is fixed to the balance tube (24) and is close to the valve cover (22) of the pilot valve. The other end of the metal wire (25) is close to the exhaust hole (211).

3. A pilot-operated safety valve according to claim 2, characterized in that: The connecting assembly (3) includes a pressure guiding pipe (31) and a return pipe (32). The two ends of the pressure guiding pipe (31) are respectively connected to the pipeline, and the two ends of the return pipe (32) are respectively connected to the pipeline. The valve seat (21) of the pilot valve also includes a pressure guiding hole (213) and a return hole (214). The two ends of the pressure guiding pipe (31) are connected to the pressure guiding hole (213) and the main valve mechanism (1) respectively, and the two ends of the return pipe (32) are connected to the return hole (214) and the main valve mechanism (1) respectively.

4. A pilot-operated safety valve according to claim 3, characterized in that: The pilot valve mechanism (2) further includes a transition component (26), which is slidably connected to the pilot valve core (23); The valve seat (21) of the pilot valve also includes a transition chamber (215) and an inlet chamber (216). A through hole (217) is provided between the transition chamber (215) and the inlet chamber (216). The transition chamber (215) is connected to the exhaust hole (211) and the return hole (214) respectively. The inlet chamber (216) is connected to the pressure guide hole (213). The transition cavity (215) is provided with a transition component (26).

5. A pilot-operated safety valve according to claim 4, characterized in that: The pilot valve core (23) includes an upper valve core (231), a middle valve core (232) and a lower valve core (233), which are arranged sequentially from top to bottom; The transition component (26) is provided with a transfer cavity (261) and a transfer hole (262) inside, and the transfer cavity (261) and the transfer hole (262) are connected by a pipe; The upper valve core (231) is inserted into the spring cavity (221) at its upper end, the middle valve core (232) passes through the through hole (217), the lower valve core (233) is inserted into the transmission cavity (261), and the transmission hole (262) and the exhaust hole (211) are connected by pipes.

6. A pilot-operated safety valve according to claim 5, characterized in that: The lower valve core (233) is provided with a transmission hole (2331), which is connected to the transition cavity (215) and the transmission cavity (261) respectively.

7. A pilot-operated safety valve according to claim 6, characterized in that: The valve guide mechanism (2) further includes a valve guide spring (27) and an adjusting screw (28). The adjusting screw (28) is inserted into the spring cavity (221). The lower end of the adjusting screw (28) is provided with the valve guide spring (27), and the lower part of the valve guide spring (27) is provided with an upper valve core (231).

8. A pilot-operated safety valve according to claim 7, characterized in that: The main valve mechanism (1) includes a main valve body (11), a main valve seat (12), a piston (13), a main valve spring (14), and a main valve cover (15). The main valve body (11) and the piston (13) are slidably connected. The main valve cover (15) is provided with a main valve spring (14) below it. The piston (13) is provided with a piston below the main valve spring (14). The upper end of the main valve seat (12) and the lower end of the piston (13) abut against each other.

9. A pilot-operated safety valve according to claim 8, characterized in that: The main valve body (11) includes an inlet (111) and an outlet (112). The piston (13) has several sets of guide grooves (131) on the outer ring of its upper end. The main valve cover (15) includes a return port (151); The inlet (111) is provided with a main valve seat (12) at the upper end. The inlet (111) is connected to the pressure guide pipe (31), and the return port (151) is connected to the return pipe (32).

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