Special gas back pressure valve

Abstract

The application relates to a special gas back pressure valve which comprises a valve body, a valve seat assembly, a diaphragm assembly, a valve cover assembly, an upper cover and an adjusting device, the diaphragm assembly comprises a diaphragm assembly, a valve rod assembly and a diaphragm flat plate with a center hole, the diaphragm assembly comprises a corrugated diaphragm with a center hole, a lifting screw, a locking nut and a lifting nut, and the valve rod assembly comprises a valve rod and a return spring. The application adopts the diaphragm assembly and the valve rod assembly to form a balanced valve rod structure, the diaphragm assembly and the valve rod are designed as a linkage assembly, the return spring and the lifting nut are combined, the effective sensing area of the diaphragm is large, small pressure fluctuation can be converted into the action of the valve rod, the sensitivity of the back pressure valve is obviously improved, the slight change of the inlet pressure can be accurately sensed, the inlet pressure can be effectively controlled even if the inlet pressure fluctuates in a very small error range, and the high-precision pressure stabilizing function is realized.

Description

Technical Field

[0001] This application relates to the field of valve technology, specifically to a special gas back pressure valve. Background Technology

[0002] Specialty gases refer to high-purity gases or mixtures of high-purity elemental gases used in specific fields with special requirements. They are widely used in various industries such as electronics, chemicals, and medicine. In the semiconductor chip manufacturing process, the purity and pressure stability of process gases (specialty gases) directly determine chip yield and performance. From photolithography and etching to chemical vapor deposition (CVD), key processes rely on high-purity process gases (with purity requirements reaching ppb level, i.e., impurity control at the part-in-a-billion level). As a core component for maintaining back pressure and stable flow in the gas delivery system, the performance of the back pressure valve directly affects process stability.

[0003] The semiconductor industry is currently facing two major technological challenges driven by trends: First, the continuous breakthroughs in process nodes, evolving from 7nm to 3nm and 2nm, mean that the tolerance of processes to gas impurities (metal particles, volatile organic compounds) and pressure fluctuations (which need to be controlled within ±1%) is approaching its limit; Second, the popularization of advanced processes, such as EUV lithography and atomic layer deposition (ALD), requires gas delivery systems to have the ultimate performance of "ultra-high purity, leak-free, and high precision".

[0004] In summary, the semiconductor industry has an urgent need for high-purity, low-leakage, high-precision, and corrosion-resistant back pressure valves. Traditional industrial-grade products can no longer meet the technical requirements of advanced processes, and there is an urgent need to develop high-purity back pressure valves that are specifically adapted to semiconductor scenarios. Utility Model Content

[0005] The purpose of this application is to provide a special gas back pressure valve that solves the problems of insufficient control accuracy and sensitivity and gas leakage of traditional back pressure valves.

[0006] To achieve the above objectives, this application provides a special gas back pressure valve, including a valve body, a valve seat assembly, a diaphragm assembly, a valve cover assembly, a top cover, and an adjustment device; The diaphragm assembly includes a diaphragm assembly, a valve stem assembly, and a diaphragm plate with a central hole. The diaphragm assembly includes a corrugated diaphragm with a central hole, a lifting screw, a locking nut, and a lifting nut. The valve stem assembly includes a valve stem and a return spring. The lifting screw has a step, with a first thread at the upper end of the step and a second thread at the lower end. The end of the lifting screw with the first thread passes through the central hole of the corrugated diaphragm and the central hole of the diaphragm plate, and is connected to the locking nut through the first thread. The step of the lifting screw is in close contact with the corrugated diaphragm, and the root of the step is welded to the corrugated diaphragm. The end of the lifting screw with the second thread has a cavity inside, in which a return spring and one end of the valve stem are installed. The other end of the valve stem passes through the lifting nut, and the lifting nut is connected to the second thread of the lifting screw. The valve body is provided with a valve seat cavity and an outlet cavity. The valve seat assembly is installed in the valve seat cavity. The valve seat assembly is provided with a through hole that communicates with the outlet cavity. The other end of the valve stem passes through the through hole of the valve seat assembly and can reciprocate within the through hole. The valve body is connected to the diaphragm assembly, the upper cover, and the valve cover assembly. An adjustment device is provided on the upper cover, and the adjustment device is connected to the diaphragm assembly.

[0007] Preferably, the upper cover is an inverted cup shape, and the valve cover assembly includes a valve cover and a valve cover nut. The cup-shaped opening of the upper cover is connected to the valve cover through the valve cover nut. A through hole is provided at the bottom of the cup shape, and the adjustment device passes through the through hole and is connected to the diaphragm assembly.

[0008] Preferably, the valve cover is a rotating body with a central through-hole, and the diaphragm assembly is disposed between the valve cover nut and the valve body. The end of the valve cover nut connected to the valve body is provided with an annular retaining edge to reserve space for the movement of the diaphragm assembly.

[0009] Preferably, a sealing ring is provided between the adjusting device and the upper cover, a sealing ring is provided between the upper cover and the valve cover nut, and a sealing ring is provided between the valve cover nut and the valve cover, thereby forming a sealed DOME pressure chamber between the diaphragm assembly, the valve cover assembly, the upper cover and the adjusting device; The upper cover cup-shaped side is provided with a connection port as a DOME pressure control port.

[0010] Preferably, the adjusting device includes a knob, an adjusting screw, and a pressure adjusting spring; The knob is located on the outside of the upper cover and is connected to the adjusting screw. The pressure regulating spring is located inside the upper cover. The adjusting screw passes through the upper cover and is connected to one end of the pressure regulating spring through the spring knob. The other end of the pressure regulating spring is connected to the diaphragm assembly.

[0011] Preferably, a sealing ring is provided between the spring button and the upper cover; The adjusting screw is connected to the upper cover by a thread.

[0012] Preferably, the valve seat assembly includes a nozzle with a central hole and a valve plate; The valve plate is disposed at the end of the nozzle near the outlet cavity. The central hole of the valve plate is coaxially arranged with the central hole of the nozzle, and the diameter of the central hole of the valve plate is smaller than the diameter of the central hole of the nozzle. The central hole of the valve plate is connected to the outlet cavity, and the valve plate is sealed with the valve body. The central hole of the valve plate forms the valve opening and closing port. The valve stem can reciprocate within the central hole of the nozzle and valve plate to open and close the valve opening / closing port.

[0013] Preferably, the valve stem includes a stem cap, a body, and a tip; The radial dimension of the rod cap is larger than the radial dimension of the main body, and the rod cap is snapped into the lifting nut and abuts against the return spring; The main body is a cylinder with a flat section, that is, the surface of the cylinder has a flat section plane parallel to the axis of the cylinder; The tip is a cylinder with a radial dimension smaller than that of the main body, and the tip and the main body are connected by a conical transition.

[0014] Preferably, the valve body is further provided with an air inlet and an air outlet. After the valve body is connected to the diaphragm assembly, a valve body pressure chamber is formed. The air inlet is connected to the valve body pressure chamber. The valve body pressure chamber is opened and closed with the outlet chamber by the movement of the valve stem. The outlet chamber is connected to the air outlet.

[0015] Preferably, the valve body is sealed to the diaphragm assembly, and an annular protective edge is provided on the outer side of the sealing connection on the valve body.

[0016] Compared with the prior art, this application has the following beneficial effects: 1. This application adopts a diaphragm assembly and a valve stem assembly to form a balanced valve stem structure. The diaphragm assembly and the valve stem are designed as a linkage assembly. Combined with the cooperation of the return spring and the lifting nut, the large effective sensing area of ​​the diaphragm can convert small pressure fluctuations into valve stem movements, which significantly improves the sensitivity of the back pressure valve. This allows it to accurately sense subtle changes in inlet pressure, thereby ensuring that even fluctuations in inlet pressure within a very small error range can be effectively controlled, achieving a high-precision pressure stabilization function.

[0017] 2. This application adopts a DOME pressure chamber and pressure control port structure, forming an independent DOME pressure chamber through multiple sets of sealing rings, and setting a connection port as a DOME pressure control port; on the one hand, users can connect an external pressure source through the connection port to realize remote or external load control, increasing the operational flexibility of the back pressure valve; on the other hand, the DOME pressure chamber can be used as a leakage gas collection chamber, which can effectively collect the gas that escapes after the diaphragm fatigues and breaks, and lead the escaped gas to a safe area through the connection port, avoiding direct leakage into the environment, which is particularly suitable for conveying special hazardous gases and greatly improving the safety of industrial sites.

[0018] 3. The valve body of this application has an annular protective edge on the outside of the sealing connection with the diaphragm assembly. That is, an annular protective edge is added to the outside of the diaphragm sealing surface of the valve body. During production, assembly or transportation, it can form a physical barrier to prevent the diaphragm sealing surface on the valve body from being directly exposed to the outside. This effectively protects the precision diaphragm sealing surface from accidental bumps and damage, thereby ensuring the product yield and sealing reliability.

[0019] 4. This application adopts a valve cover nut with an annular buckle structure, which provides sufficient space for the expansion and contraction of the diaphragm assembly and the reciprocating motion of the valve stem, avoids motion interference, and indirectly improves the pressure regulation response speed and accuracy. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of this application; Figure 2 This is a cross-sectional view of the valve body in this application; Figure 3 These are cross-sectional and isometric views of the valve seat assembly of this application; Figure 4 These are the front view and isometric view of the valve stem in this application; Figure 5 This is a cross-sectional view of the diaphragm assembly of this application; Figure 6 These are cross-sectional and exploded views of the diaphragm assembly of this application; Figure 7 These are the cross-sectional and isometric views of the lifting nut in this application.

[0021] In the picture: Valve body 1; Inlet 1-1; Outlet 1-2; Valve seat cavity 1-3; Outlet cavity 1-4; Diaphragm sealing surface 1-5; Annular guard 1-6; Valve seat assembly 2; Nozzle 2-1; Valve plate 2-2; Rounded corner seal 2-3; Diaphragm assembly 3; Corrugated diaphragm 3-1; Lifting screw 3-2; First thread 3-21; Lifting screw flat section 3-22; Step 3-23; Second thread 3-24; Valve stem 4; cone 4-1; stem cap 4-2; flat surface 4-3; body 4-4; tip 4-5; 5. Return spring; 6. Lifting nut; 6-1. Flat part of lifting nut; 6-2. Round hole of valve stem; 6-3. Internal thread; 16. Locking nut; 7. Diaphragm plate; Valve cover 8; Valve cover nut 9; Top cover 10; Connection port 10-1; Valve opening / closing port 111; DOME pressure chamber 113; Pressure regulating spring 11; spring knob 12; knob 13; adjusting screw 18; Spring button sealing ring 14; valve cover sealing ring 15; top cover sealing ring 17. Detailed Implementation

[0022] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0023] A special gas back pressure valve, such as Figure 1-7 As shown, the device includes a valve body 1, a valve seat assembly 2, a diaphragm assembly, a valve cover assembly, a top cover 10, and an adjusting device. The diaphragm assembly includes a diaphragm assembly 3, a valve stem assembly, and a diaphragm plate 7 with a central hole. The diaphragm assembly 3 includes a corrugated diaphragm 3-1 with a central hole, a lifting screw 3-2, a locking nut 16, and a lifting nut 6. The valve stem assembly includes a valve stem 4 and a return spring 5. The lifting screw 3-2 has a step 3-23. One end of the upper part of the step 3-23 is provided with a first thread 3-21, and one end of the lower part of the step 3-23 is provided with a second thread 3-24. The end of the lifting screw 3-2 with the first thread 3-21 passes through the central hole of the corrugated diaphragm 3-1 and the central hole of the diaphragm plate 7, and is connected to the locking nut 16 through the first thread 3-21. Step 3-23 is tightly attached to the corrugated diaphragm 3-1, and the root of step 3-23 is welded to the corrugated diaphragm 3-1; the lifting screw 3-2 has a cavity inside one end with the second thread 3-24, and a return spring 5 and one end of the valve stem 4 are installed in the cavity. The other end of the valve stem 4 passes through the lifting nut 6, and the lifting nut 6 is connected to the second thread 3-24 of the lifting screw 3-2; the valve body 1 is provided with a valve seat cavity 1-3 and an outlet cavity 1-4. The valve seat assembly 2 is installed in the valve seat cavity 1-3. The valve seat assembly 2 is provided with a through hole, which communicates with the outlet cavity 1-4. The other end of the valve stem 4 passes through the through hole of the valve seat assembly 2 and can reciprocate within the through hole; the valve body 1 is connected to the diaphragm assembly 3, the upper cover 10, and the valve cover assembly. The upper cover 10 is provided with an adjustment device, which is connected to the diaphragm assembly 3.

[0024] The corrugated diaphragm 3-1 of this application features high sensitivity and strong sealing performance. Its corrugated structure amplifies the pressure sensing signal, enabling rapid response to pressure difference changes (pressure difference changes between the DOME pressure chamber 113 and the valve body pressure chamber), driving the valve stem 4 to move precisely and improving pressure regulation sensitivity. The corrugated diaphragm 3-1 can be made of corrugated stainless steel. In some embodiments, laser welding can be used to weld the lifting screw 3-2 to the corrugated diaphragm 3-1, ensuring the sealing of the weld joint, greatly improving the mechanical strength of the lifting screw 3-2, increasing the lifting force, and extending the service life of the corrugated diaphragm 3-1 and its ability to cope with harsh working conditions.

[0025] This application employs a diaphragm assembly 3 and a valve stem assembly to form a balanced valve stem 4 structure. The diaphragm assembly 3 and the valve stem 4 are designed as a linkage assembly. Combined with the cooperation of the return spring 5 and the lifting nut 6, the large effective sensing area of ​​the diaphragm can convert minute pressure fluctuations into the action of the valve stem 4, significantly improving the sensitivity of the back pressure valve. This allows it to accurately sense minute changes in the inlet pressure, thereby ensuring that even fluctuations in the inlet pressure within a very small error range can be effectively controlled, achieving a high-precision pressure stabilization function.

[0026] In some embodiments, such as Figure 1 As shown, the upper cover 10 is an inverted cup shape. The valve cover assembly includes a valve cover 8 and a valve cover nut 9. The cup-shaped opening of the upper cover 10 is connected to the valve cover 8 through the valve cover nut 9. A through hole is provided at the bottom of the cup shape, through which the adjusting device is connected to the diaphragm assembly 3. The inverted cup-shaped structure provides a closed installation space for the internal components, simplifies the assembly process, ensures the coaxiality of the transmission connection between the adjusting device and the diaphragm assembly 3, guarantees the stability of pressure regulation, and adapts to high-precision control requirements.

[0027] In some embodiments, such as Figure 1 As shown, the valve cover 8 is a centrally permeable rotating body. The diaphragm assembly 3 is disposed between the valve cover nut 9 and the valve body 1. The end of the valve cover nut 9 connected to the valve body 1 is provided with an annular retaining edge to reserve space for the movement of the diaphragm assembly 3. The permeable structure facilitates pressure transmission, and the annular retaining edge prevents interference between the diaphragm assembly 3 and other components during movement. At the same time, it improves the assembly and positioning accuracy of the valve cover assembly and the valve body 1, ensures the flexibility of the diaphragm assembly 3 in expansion and contraction, and indirectly improves the pressure response speed.

[0028] In some embodiments, such as Figure 1 As shown, a sealing ring (spring button sealing ring 14) is provided between the adjusting device and the upper cover 10, a sealing ring (upper cover sealing ring 17) is provided between the upper cover 10 and the valve cover nut 9, and a sealing ring (valve cover sealing ring 15) is provided between the valve cover nut 9 and the valve cover 8, thereby forming a sealed DOME pressure chamber 113 between the diaphragm assembly 3, the valve cover assembly, the upper cover 10, and the adjusting device; the upper cover 10 has a connection port 10-1 on its cup-shaped side as a DOME pressure control port. By setting multiple sealing rings, a sealed DOME pressure chamber 113 is formed between the core components, which, together with the DOME pressure control port on the side of the upper cover 10, enables precise pressure control of the pressure chamber. On the one hand, users can connect to an external pressure source through connection port 10-1 to achieve remote or external load control, increasing the operational flexibility of the back pressure valve; on the other hand, the DOME pressure chamber 113 can be used as a leakage gas collection chamber, which can effectively collect the gas that escapes after the diaphragm fatigues and breaks, and lead the escaped gas to a safe area through connection port 10-1, avoiding direct leakage into the environment. It is particularly suitable for conveying special hazardous gases and greatly improves the safety of industrial sites.

[0029] In some embodiments, such as Figure 1 As shown, the adjusting device includes a knob 13, an adjusting screw 18, and a pressure regulating spring 11. The knob 13 is located on the outside of the upper cover 10 and is connected to the adjusting screw 18. The pressure regulating spring 11 is located inside the upper cover 10. The adjusting screw 18 passes through the upper cover 10 and is connected to one end of the pressure regulating spring 11 via a spring knob 12. The other end of the pressure regulating spring 11 is connected to the diaphragm assembly 3. A spring knob sealing ring 14 is provided between the spring knob 12 and the upper cover 10. The adjusting screw 18 is connected to the upper cover 10 via a threaded connection. The adjusting device adopts a transmission structure of "knob - adjusting screw - pressure regulating spring," and the threaded connection enables precise adjustment of the preload of the pressure regulating spring 11. The knob 13 is easy to operate, the threaded transmission has high precision, and the pressure regulating spring 11 can smoothly transmit the adjusting force to the diaphragm assembly 3, achieving linear pressure adjustment, improving the control accuracy of the back pressure valve, and adapting to the pressure parameter requirements of different process scenarios.

[0030] In some embodiments, such as Figure 3 As shown, the valve seat assembly 2 includes a nozzle 2-1 with a central hole and a valve plate 2-2. The valve plate 2-2 is disposed at the end of the nozzle 2-1 near the outlet cavity 1-4. The central hole of the valve plate 2-2 is coaxially arranged with the central hole of the nozzle 2-1, and the diameter of the central hole of the valve plate 2-2 is smaller than that of the central hole of the nozzle 2-1. The central hole of the valve plate 2-2 communicates with the outlet cavity 1-4. The valve plate 2-2 is sealed to the valve body 1 by a rounded corner seal 2-3. The central hole of the valve plate 2-2 forms a valve opening / closing port 111. The valve stem 4 can reciprocate within the central holes of the nozzle 2-1 and the valve plate 2-2 to open and close the valve opening / closing port 111. The coaxial structure ensures precise contact between the valve stem 4 and the valve opening / closing port 111 during reciprocating motion. The small-diameter valve opening / closing port 111 improves sealing reliability, reduces gas leakage, optimizes the gas flow path, reduces pressure loss, ensures stable gas flow, and meets the high-precision requirements of semiconductor processes for airflow control.

[0031] In some embodiments, such as Figure 4As shown, the valve stem 4 includes a stem cap 4-2, a body 4-4, and a tip 4-5; the radial dimension of the stem cap 4-2 is larger than the radial dimension of the body 4-4, and the stem cap 4-2 is engaged in the valve stem circular hole 6-2 of the lifting nut 6 and abuts against the return spring 5; the body 4-4 is a cylinder with a flat section, that is, the surface of the cylinder has a flat section plane 4-3 parallel to the cylinder axis; the tip 4-5 is a cylinder, and its radial dimension is smaller than the radial dimension of the body 4-4, and the tip 4-5 and the body 4-4 are connected by a cone 4-1. It adopts a three-section structure. The main body 4-4 has a flat plane 4-3, and the tip 4-5 is connected by a cone 4-1. The rod cap 4-2 achieves stable contact with the return spring 5. The flat plane 4-3 is the gas flow area. The cone 4-1 transitions to the small-diameter tip 4-5 to improve the sealing fit with the valve opening and closing port 111. The overall structure takes into account both rigidity and sealing performance, so as to achieve rapid opening and closing and precise sealing of the valve opening and closing port 111.

[0032] In some embodiments, such as Figure 2 As shown, the valve body 1 is also provided with an air inlet 1-1 and an air outlet 1-2. The valve body 1 and the diaphragm assembly 3 are connected through the diaphragm sealing surface 1-5 to form a valve body pressure chamber. The air inlet 1-1 is connected to the valve body pressure chamber. The valve body pressure chamber is opened and closed with the outlet chamber 1-4 by the movement of the valve stem 4. The outlet chamber 1-4 is connected to the air outlet 1-2, forming a clear gas flow path.

[0033] In some embodiments, such as Figure 2 As shown, the valve body 1 and the diaphragm assembly 3 are sealed together via diaphragm sealing surfaces 1-5. An annular protective edge 1-6 is provided on the outer side of the sealing connection on the valve body 1. This enhances the structural strength of the sealing connection, preventing deformation of the connection due to long-term use or pressure shock, and also prevents external impurities from entering the sealing surface, protecting the sealing ring from wear, extending the service life of the sealing structure, and further ensuring the leak-free performance of the back pressure valve, thus meeting the long-term stable operation requirements of the semiconductor industry.

[0034] In a preferred embodiment, its structure, working principle, and effects are as follows: Valve body 1 is a cylindrical shape with a cavity, including an air inlet 1-1, an air outlet 1-1, a valve seat cavity 1-3, an outlet cavity 1-4, and a diaphragm sealing surface 1-5 (the sealing connection between the valve body and the diaphragm assembly). Compared with a conventional valve body, an annular protective edge 1-6 is added to the outside of the diaphragm sealing surface, which can effectively protect the diaphragm sealing surface 1-5 during production. Figure 2 As shown.

[0035] Valve seat assembly 2 includes a nozzle 2-1 and a valve plate 2-2. The nozzle 2-1 is a screw-type plug with a central through-hole and an air groove at the top. The end of the valve plate 2-2 connected to the nozzle 2-1 has a right angle at the bottom and a rounded corner seal 2-3 at the through-hole. The valve plate 2-2 is inserted into the countersunk hole at the bottom of the nozzle 2-1 with the right angle facing downwards. Figure 3 As shown.

[0036] The diaphragm assembly 3 includes a corrugated diaphragm 3-1 with a central hole and a lifting screw 3-2. The upper end of the lifting screw 3-2 has a first thread 3-21, and above the first thread is a lifting screw flat section 3-22. The lifting screw has a step 3-23, and the lower end of the step has a second thread 3-24. An internal hole is opened inside the lower end of the lifting screw. The end of the lifting screw 3-2 with the first thread 3-21 is inserted into the central hole of the corrugated diaphragm 3-1. The end face of the step 3-22 is tightly against the underside of the corrugated diaphragm 3-1. The corrugated diaphragm 3-1 and the lifting screw 3-2 are welded together using laser welding. Figure 5 As shown.

[0037] The valve stem 4 includes a stem cap 4-2, a body 4-4, and a tip 4-5; the body 4-4 and the tip 4-5 are connected by a tapered joint 4-1. The body 4-4 has a flat surface 4-3, which is the area where the medium fluid flows. Figure 4 As shown.

[0038] Return spring 5, a common cylindrical compression spring.

[0039] The lifting nut 6 is cylindrical in shape and has a lifting nut flat section 6-1, which is designed for locking and unlocking functions. The lifting nut 6 has a valve stem hole 6-2 and internal threads 6-3 inside. For example... Figure 7 As shown.

[0040] The diaphragm plate 7 is a flat-bottomed structure with a central through hole.

[0041] Locking nut 16, ordinary nut, can be equipped with standard spring washer.

[0042] Valve cover 8 is a rotating body with a central through-hole. One end has a threaded inner hole with a sealing groove on the outside of the thread. The other end has flanges on both the inner and outer sides, with a boss at the lower end of the flange. The inner hole has an inner step.

[0043] Valve cover nut 9, one end has internal thread, and the other end has an annular buckle on the inner hole.

[0044] The upper cover 10 is an inverted cup shape with a countersunk cavity at the bottom opening; the lower outer edge is provided with threads and a flange edge, and a sealing groove is provided between the threads and the flange edge; the upper bottom is thickened, and the center is an adjustment threaded hole; a threaded hole 10-1 is provided on the side of the countersunk cavity.

[0045] The adjustment device includes a knob 13, an adjusting screw 18, and a pressure adjusting spring 11. The pressure adjusting spring 11 is a standard cylindrical compression spring. The spring knob 12 is a disc-shaped knob with a central boss and a sealing groove on its outer edge, configured as a piston. The spring knob sealing ring 14 is a standard annular sealing ring, which is optional.

[0046] Valve cover sealing ring 15, a standard annular sealing ring, is an optional component.

[0047] The top cover sealing ring 17 is a standard annular sealing ring and is an optional component.

[0048] A diaphragm plate 7 and a locking nut 16 are sequentially fitted onto the end of the lifting screw 3-2 of the diaphragm assembly 3 with the first thread 3-21, and the locking nut 16 is screwed into the first thread 3-21. A return spring 5 is placed in the internal cavity of the end of the lifting screw 3-2 with the second thread 3-24. The rod cap 4-2 of the valve stem 4 passes through the lifting nut 6, and the return spring 5 is compressed by a special compression tool, so that the second thread 3-24 of the lifting screw 3-2 is screwed into the thread of the lifting nut 6. The lifting nut flat part 6-1 is clamped and the locking nut 16 is tightened, thus forming the diaphragm assembly. Figure 6 As shown.

[0049] The valve seat assembly 2 is placed inside the valve seat cavity 1-3 of the valve body 1. The valve seat assembly 2 is screwed into the valve seat cavity 1-3 of the valve body 1, and the valve plate 2-2 is sealed to the bottom surface of the valve seat cavity 1-3. Under the pressure regulating force of the pressure regulating spring 11, the cone 4-1 of the valve stem 4 presses on the rounded corner seal 2-3 of the valve plate 2-2, forming the valve opening and closing port 111.

[0050] The diaphragm assembly is placed on the valve body 1, at which point the outer edge of the corrugated diaphragm 3-1 adheres to the diaphragm sealing surface 1-5 of the valve body 1. The annular protective edge 1-6 of the valve body 1 effectively protects the diaphragm sealing surface 1-5 from damage during operation. The valve stem 4 and valve plate 2-2 form a sealed open state; when the regulating device adjusts the pressure, the valve stem 4 and valve plate 2-2 form a sealed closed state.

[0051] Place the valve cover 8 with the valve cover sealing ring 15 on the outer edge of the corrugated diaphragm 3-1, tighten the valve cover nut 9, and apply a certain torque to ensure a seal between the corrugated diaphragm 3-1 and the diaphragm sealing surface 1-5. An annular cavity is formed between the valve cover 8 and the diaphragm plate 7.

[0052] Place the pressure regulating spring 11 on the diaphragm plate 7, and place the spring button 12 with the spring button sealing ring 14 on the upper part of the pressure regulating spring 11. Put the upper cover 10 on the outside of the pressure regulating spring 11 and screw it into the valve cover 8 to fix it. Finally, install the regulating device.

[0053] Furthermore, the spring cavity, which is sealed by the spring button sealing ring 14, valve cover sealing ring 15, and upper cover sealing ring 17, enclosing the diaphragm assembly 3, valve cover 8, upper cover 10, and spring button 12, is completely sealed to form the DOME pressure chamber 113. The connection port 10-1 (which can be a screw hole) on the side of the upper cover 10 forms the DOME pressure control port, used for external control loading, increasing the control function of the back pressure valve. It can also serve as a collection chamber to effectively collect the gas that escapes after the diaphragm fatigues and ruptures, and guide the escaped gas to a safe area.

[0054] During operation, rotating the adjustment device pushes the spring knob 12, compresses the pressure regulating spring 11, and simultaneously pushes the diaphragm assembly downward, causing the corrugated diaphragm 3-1 to deform, loading the diaphragm assembly 3, compressing the reset spring 5, closing the valve opening / closing port 111, and setting the back pressure of the back pressure valve.

[0055] When the intake port 1-1 is connected to the intake pressure, the airflow enters the valve seat cavity 1-3 and / or the valve body pressure cavity, is throttled by the valve opening / closing 111, and then enters the outlet cavity 1-4, and is output through the outlet port 1-2. The working principle is similar to that of a normal back pressure valve. The inlet pressure acting below the diaphragm assembly 3 pushes the diaphragm assembly upward, forming a dynamic balance with the compression force of the pressure regulating spring 11. When the inlet pressure increases, the pressure acting on the lower side of the diaphragm assembly is greater than the elastic force of the pressure regulating spring 11, pushing the diaphragm assembly upward and pulling the valve stem 4 upward, thus increasing the valve opening / closing port 111, reducing throttling, and lowering the input pressure until the valve opening / closing port 111 closes. When the intake pressure decreases, the elastic force of the pressure regulating spring 11 is greater than the pressure acting on the lower side of the diaphragm assembly, driving the valve 4 downward, thus decreasing the valve opening / closing port 111, reducing throttling, and lowering the output pressure until the valve opening / closing port 111 is completely closed.

[0056] If you want to control the output pressure remotely, you can control the back pressure by increasing or decreasing the pressure through the DOME pressure control port.

[0057] The diaphragm assembly adopts a balanced valve stem structure, making the diaphragm assembly 3 and the valve stem 4 form a moving assembly. Even a slight up-and-down movement of the diaphragm assembly 3 will amplify the sealing performance of the valve stem 4 and the valve plate 2-2. In other words, the inlet pressure drives the diaphragm assembly 3 to move up and down, and the valve stem 4 and the valve plate 2-2 will continuously open and close. Due to the large effective sensing area of ​​the diaphragm assembly 3, the back pressure valve can sensitively sense the inlet pressure, ensuring that the inlet pressure fluctuates within a very small error range.

[0058] The annular protective edge 1-6 of the valve body 1 can effectively protect the diaphragm sealing surface 1-5 during the production process.

[0059] The DOME pressure chamber 113 and DOME pressure control port can control the output pressure through external pressure loading, thus enhancing the function of the back pressure valve. The DOME pressure chamber 113 and DOME pressure control port can also function as collection chambers, effectively collecting gas that escapes after diaphragm fatigue rupture and guiding it to a safe area. Suitable for conveying highly toxic, harmful, flammable, and explosive gases, improving safety.

[0060] It adopts a metal diaphragm, a balanced valve stem structure, and a waste collection port, which is convenient for conveying special gas media, such as highly toxic, harmful, flammable and explosive dangerous gases, and gases that are prone to crystallization.

[0061] The valve adopts a balanced stem structure. When the medium pressure decreases or there is no pressure in the pipeline, the force of the pressure regulating spring 11 does not act on the valve seat sealing surface. The force on the valve seat is only the force of the medium on the valve stem 4 and the force of the return spring 5 compression on the valve seat, which increases the service life of the back pressure valve.

[0062] In this application, the use of directional terms such as "up," "down," "left," "right," "bottom," and "top" is defined relative to the directions shown in the accompanying drawings and is used only to indicate relative positional relationships. These relative positional relationships may change accordingly when the absolute position of the described object changes. These or other directional terms should not be construed as restrictive.

[0063] The use of terms such as "a," "an," "a kind," and "the" in this application does not indicate a quantity limitation and may indicate a singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this application are intended to cover non-exclusive inclusion; the terms "first," "second," and "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0064] In this application, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may not be directly connected to the other devices but may have an intermediary device.

[0065] Furthermore, this application does not discuss in detail the technologies and equipment known to those skilled in the art, but where appropriate, such technologies and equipment should be considered part of the specification.

[0066] The specific embodiments of this application have been described above. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this application. Unless otherwise specified, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other.

Claims

1. A special gas back pressure valve, characterized in that, Includes valve body, valve seat assembly, diaphragm assembly, valve cover assembly, top cover, and regulating device; The diaphragm assembly includes a diaphragm assembly, a valve stem assembly, and a diaphragm plate with a central hole. The diaphragm assembly includes a corrugated diaphragm with a central hole, a lifting screw, a locking nut, and a lifting nut. The valve stem assembly includes a valve stem and a return spring. The lifting screw has a step, with a first thread at the upper end of the step and a second thread at the lower end. The end of the lifting screw with the first thread passes through the central hole of the corrugated diaphragm and the central hole of the diaphragm plate, and is connected to the locking nut through the first thread. The step of the lifting screw is in close contact with the corrugated diaphragm, and the root of the step is welded to the corrugated diaphragm. The end of the lifting screw with the second thread has a cavity inside, in which a return spring and one end of the valve stem are installed. The other end of the valve stem passes through the lifting nut, and the lifting nut is connected to the second thread of the lifting screw. The valve body is provided with a valve seat cavity and an outlet cavity. The valve seat assembly is installed in the valve seat cavity. The valve seat assembly is provided with a through hole that communicates with the outlet cavity. The other end of the valve stem passes through the through hole of the valve seat assembly and can reciprocate within the through hole. The valve body is connected to the diaphragm assembly, the upper cover, and the valve cover assembly. An adjustment device is provided on the upper cover, and the adjustment device is connected to the diaphragm assembly.

2. The special gas back pressure valve according to claim 1, characterized in that, The upper cover is an inverted cup shape. The valve cover assembly includes a valve cover and a valve cover nut. The cup-shaped opening of the upper cover is connected to the valve cover through the valve cover nut. A through hole is provided at the bottom of the cup shape. The adjustment device passes through the through hole and is connected to the diaphragm assembly.

3. The special gas back pressure valve according to claim 2, characterized in that, The valve cover is a rotating body with a central open structure. The diaphragm assembly is located between the valve cover nut and the valve body. The end of the valve cover nut that connects to the valve body is provided with an annular retaining edge to reserve space for the movement of the diaphragm assembly.

4. The special gas back pressure valve according to claim 2, characterized in that, A sealing ring is provided between the regulating device and the upper cover, a sealing ring is provided between the upper cover and the valve cover nut, and a sealing ring is provided between the valve cover nut and the valve cover, thereby forming a sealed DOME pressure chamber between the diaphragm assembly, the valve cover assembly, the upper cover, and the regulating device. The upper cover cup-shaped side is provided with a connection port as a DOME pressure control port.

5. The special gas back pressure valve according to claim 1, characterized in that, The adjusting device includes a knob, an adjusting screw, and a pressure adjusting spring; The knob is located on the outside of the upper cover and is connected to the adjusting screw. The pressure regulating spring is located inside the upper cover. The adjusting screw passes through the upper cover and is connected to one end of the pressure regulating spring through the spring knob. The other end of the pressure regulating spring is connected to the diaphragm assembly.

6. The special gas back pressure valve according to claim 5, characterized in that, A sealing ring is provided between the spring button and the top cover; The adjusting screw is connected to the upper cover by a thread.

7. The special gas back pressure valve according to claim 1, characterized in that, The valve seat assembly includes a nozzle having a central orifice and a valve plate; The valve plate is disposed at the end of the nozzle near the outlet cavity. The central hole of the valve plate is coaxially arranged with the central hole of the nozzle, and the diameter of the central hole of the valve plate is smaller than the diameter of the central hole of the nozzle. The central hole of the valve plate is connected to the outlet cavity, and the valve plate is sealed with the valve body. The central hole of the valve plate forms the valve opening and closing port. The valve stem can reciprocate within the central hole of the nozzle and valve plate to open and close the valve opening / closing port.

8. The special gas back pressure valve according to claim 1, characterized in that, The valve stem includes a stem cap, a body, and a tip; The radial dimension of the rod cap is larger than the radial dimension of the main body, and the rod cap is snapped into the lifting nut and abuts against the return spring; The main body is a cylinder with a flat section, that is, the surface of the cylinder has a flat section plane parallel to the axis of the cylinder; The tip is a cylinder with a radial dimension smaller than that of the main body, and the tip and the main body are connected by a conical transition.

9. The special gas back pressure valve according to claim 1, characterized in that, The valve body is also provided with an air inlet and an air outlet. After the valve body is connected to the diaphragm assembly, a valve body pressure chamber is formed. The air inlet is connected to the valve body pressure chamber. The valve body pressure chamber is opened and closed with the outlet chamber by the movement of the valve stem. The outlet chamber is connected to the air outlet.

10. The special gas back pressure valve according to claim 1, characterized in that, The valve body is sealed to the diaphragm assembly, and a ring-shaped protective edge is provided on the outside of the sealing connection on the valve body.

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