Large bore normally open pneumatic valve

Abstract

The utility model discloses a big passageway normally open pneumatic valve relates to fluid control valve technical field, solves the technical problem of traditional pneumatic valve gas loss power loss cannot manual operation. Including pneumatic valve body, be equipped with the flow passageway cavity and control cavity on the pneumatic valve body, be provided with the liquid inlet and liquid outlet on the pneumatic valve body, and the liquid inlet and liquid outlet are communicated in the flow passageway cavity, and the flow passageway cavity is slidably provided with the valve assembly, and is equipped with the valve elastic member between the valve assembly and pneumatic valve body, and the valve elastic member can provide the valve assembly with the pre -tightening force, the other end of piston assembly cooperates with the handle set up on the pneumatic valve body, is provided with the piston elastic member in the control cavity, and the pre -tightening force provided by piston elastic member can make piston assembly promote valve assembly and compress valve elastic member and move to make the flow passageway cavity be in normally open state, be equipped with the pneumatic control structure that cooperates with piston assembly on the pneumatic valve body, and through handle and pneumatic control structure can all drive piston assembly to move and promote valve assembly to slide and close the flow passageway cavity.

Description

Technical Field

[0001] This utility model relates to the field of fluid control valve technology, and in particular to a large-diameter normally open pneumatic valve. Background Technology

[0002] In industrial automation control systems, pneumatic valves are widely used due to their advantages such as fast response speed, good explosion-proof performance, and strong environmental adaptability. Traditional normally open pneumatic valves are mainly divided into two categories: purely pneumatic control type and manually shut-off type. Purely pneumatic control valves cannot be manually operated in case of air loss or electrical control system failure, while manual valves lack remote automatic control functions.

[0003] For example, Chinese utility model patent CN202215830U discloses a normally closed pneumatic valve. This normally closed pneumatic valve includes an upper valve cover, a valve body, and a lower valve cover. A pneumatic actuator is located on the upper part of the valve body, forming an air chamber with the upper part of the valve body. A first spring is fitted inside the upper valve cover to press against the pneumatic actuator. The valve body contains a valve stem and a gas flow path. The lower valve cover has a gas pipe that connects to the gas flow path of the valve body. The lower end of the valve stem has an inverted conical valve core, and a second spring is fitted under the inverted conical valve core. A star-shaped ring located below the inverted conical valve core and conforming to the conical surface is engaged at the connection point between the lower valve cover and the gas flow path of the valve body. The upper end of the valve stem extends into the air chamber and abuts against the pneumatic actuator. This utility model can achieve a normally closed function and also achieve pneumatic opening and closing, but lacks manual adjustment capability.

[0004] To achieve dual control functionality, existing technologies typically employ parallel connection of manual valves upstream or downstream of the pneumatic valve, or the addition of a manual overrunning device to the external pneumatic actuator. However, these solutions have the following drawbacks: The system is highly complex: it requires additional piping and valves, and is large and heavy, which does not conform to the trend of miniaturization in modern industrial equipment. Reduced reliability: Increased connection points lead to a higher risk of leakage; Hysteresis: Parallel structures increase flow resistance, affecting the dynamic response characteristics of pneumatic valves; Increased costs: More parts and components lead to higher installation and maintenance costs.

[0005] Especially in applications requiring large diameter and high reliability, such as chemical, energy, shipbuilding, and aerospace industries, existing technologies struggle to simultaneously meet the demands for manual / automatic dual-mode integration, rapid response, and modular installation. Therefore, there is an urgent need for a large-diameter normally open pneumatic valve that is compact, highly reliable, and combines pneumatic automatic and manual direct-operation functions. Utility Model Content

[0006] To address the shortcomings in the aforementioned background technology, this utility model proposes a large-diameter normally open pneumatic valve, which solves the technical problem that traditional pneumatic valves cannot be manually operated when they lose air or power, and realizes an innovative design of single-valve dual-mode control.

[0007] The technical solution of this utility model is implemented as follows: A large-diameter normally open pneumatic valve includes a pneumatic valve body, which has a flow channel cavity and a control cavity. The pneumatic valve body has an inlet and an outlet, which are connected in the flow channel cavity. A valve assembly is slidably disposed in the flow channel cavity, and a valve elastic element is disposed between the valve assembly and the pneumatic valve body. The valve elastic element can provide a pre-tightening force to the valve assembly. A piston assembly is slidably disposed in the control cavity. One end of the piston assembly passes into the flow channel cavity and its end cooperates with the valve assembly. The other end of the piston assembly cooperates with a handle disposed on the pneumatic valve body. A piston elastic element is disposed in the control cavity. The pre-tightening force provided by the piston elastic element can cause the piston assembly to push the valve assembly to move and compress the valve elastic element, thereby keeping the flow channel cavity in a normally open state. The pneumatic valve body has a pneumatic control structure that cooperates with the piston assembly. Both the handle and the pneumatic control structure can drive the piston assembly to move and compress the piston elastic element. At the same time, the valve elastic element resets and pushes the valve assembly to slide and close the flow channel cavity.

[0008] Preferably, the piston assembly includes a piston slidably disposed in the control chamber, the piston being fixedly connected to the piston rod, and the piston elastic element including a piston spring disposed between the piston and the pneumatic valve body, the piston spring being located on the side of the piston away from the flow channel cavity, the pneumatic valve body being provided with a connecting hole I communicating with the flow channel cavity and the control chamber, and the piston rod passing through the connecting hole I into the flow channel cavity.

[0009] Preferably, the pneumatic valve body includes a valve body and a cylinder body connected together. A flow passage cavity is opened on the valve body, a control cavity is opened on the cylinder body, a connection hole I is opened on the valve body, a connection port corresponding to the connection hole I is opened on the valve body, an end cap is detachably installed on the connection port, and a valve assembly is installed on the end cap.

[0010] Preferably, a partition is fixedly installed inside the flow channel cavity, which divides the flow channel cavity into a first chamber and a second chamber. The first chamber and the second chamber are connected at the connection port. The first chamber and the second chamber are respectively connected to the liquid inlet and the liquid outlet. The valve body and the partition at the connection port are respectively provided with sealing surfaces. The valve assembly cooperates with the sealing surface to control the communication relationship between the first chamber and the second chamber.

[0011] Preferably, the valve assembly includes a valve slidably disposed on the end cover, and the valve elastic element includes a valve spring disposed between the valve and the end cover. The valve spring can press the valve tightly against the sealing surface, and the preload provided by the valve spring is less than the preload provided by the piston spring.

[0012] Preferably, the handle includes a handle rod, a connecting hole II is provided on the cylinder body, the middle part of the handle rod is engaged with the connecting hole II, the lower end of the handle rod is movably connected to the piston rod, and the upper end of the handle rod is connected to the grip.

[0013] Preferably, the pneumatic control structure includes a first interface and a second interface formed on the cylinder body. The first interface and the second interface are respectively located on both sides of the piston. The first interface is used to introduce or extract control gas into the control chamber on one side of the piston, and the second interface is used to maintain the air pressure balance in the control chamber on the other side of the piston. The first interface is equipped with an NPT compression fitting, and the second interface is equipped with a silencer. Sealing rings are provided on the connecting hole I, connecting hole II, connecting port, and valve. Connecting flanges are provided on both the liquid inlet and the liquid outlet.

[0014] The beneficial effects of this utility model are: By setting up a valve assembly in conjunction with a piston assembly, the flow passage cavity can be kept in a normally open state under the synergistic action of the valve elastic element and the piston elastic element, thus meeting the normally open use control requirements of the normally open pneumatic valve. By setting up a piston assembly in conjunction with a pneumatic control structure, the piston assembly can be pneumatically controlled to drive the valve assembly to open and close, thereby achieving pneumatic control. By further setting up a handle, the piston assembly can be manually moved, thereby achieving manual control of the valve assembly to open and close the flow passage cavity. This allows for automatic opening in the event of a gas or power failure, ensuring safety, while retaining manual operation capability for easy emergency maintenance.

[0015] This utility model adopts a dual-mode integrated design, integrating manual mechanical control and pneumatic automatic control into a single valve structure. It eliminates the need for external parallel pipelines, reduces the size and weight of the valve body, and lowers the complexity of the system. It is particularly suitable for applications with limited space and large-diameter requirements. Attached Figure Description

[0016] To more clearly illustrate the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the normally open state structure of the normally open pneumatic valve of this utility model; Figure 2 This is a schematic diagram of the normally open pneumatic valve in the pneumatically closed state according to this utility model; Figure 3 This is a schematic diagram of the normally open pneumatic valve of this utility model in the manual closed state; In the diagram: 1a-flow channel cavity, 1b-control cavity, 3-piston assembly, 4-valve assembly, 5-handle, 6-pneumatic control structure, 11-valve body, 12-cylinder body, 13-connection port, 14-end cover, 15-partition plate, 16-first chamber, 17-second chamber, 18-sealing surface, 31-piston, 32-piston rod, 33-piston spring, 41-valve, 42-valve spring, 51-handle rod, 52-grip, 61-first interface, 62-second interface. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] like Figure 1 , 2 As shown in Figure 3, in Embodiment 1, a large-diameter normally open pneumatic valve includes a pneumatic valve body. The pneumatic valve body has a flow channel cavity 1a and a control cavity 1b. The pneumatic valve body has an inlet and an outlet, which are connected within the flow channel cavity 1a. A valve assembly 4 is disposed within the flow channel cavity 1a. A valve elastic element is disposed between the valve assembly 4 and the pneumatic valve body. The valve elastic element can provide a pre-tightening force to the valve assembly 4, thereby closing the flow channel cavity using the valve assembly without the action of other external forces. By setting the valve assembly in conjunction with the piston assembly, the flow channel cavity can be kept in a normally open state under the synergistic action of the valve elastic element and the piston elastic element, thus meeting the normally open use control requirements of the normally open pneumatic valve.

[0020] A piston assembly 3 is slidably disposed within the control chamber 1b. One end of the piston assembly 3 penetrates into the flow channel chamber 1a and engages with the valve assembly 4. The other end of the piston assembly 3 engages with a handle 5 disposed on the pneumatic valve body. A piston elastic element is disposed within the control chamber 1b. The preload provided by the piston elastic element enables the piston assembly 3 to push the valve assembly 4 to move and compress the valve elastic element, thereby keeping the flow channel chamber 1a in a normally open state. The pneumatic valve body is provided with a pneumatic control structure 6 that engages with the piston assembly 3. Both the handle 5 and the pneumatic control structure 6 can drive the piston assembly 3 to move and compress the piston elastic element. Simultaneously, the valve elastic element resets and pushes the valve assembly 4 to slide, closing the flow channel chamber 1a.

[0021] In this embodiment, by setting a piston assembly in conjunction with a pneumatic control structure, the piston assembly can be pneumatically controlled to drive the valve assembly to open, thus achieving pneumatic control of opening and closing. By further setting a handle, the piston assembly can be manually moved, thereby achieving manual control of the valve assembly to open and close the flow channel cavity. This realizes a dual-mode integrated design of pneumatic and manual control, which can automatically open in the event of a gas or power failure to ensure safety, while retaining manual operation capability for easy emergency maintenance.

[0022] Specifically, in this embodiment, the piston assembly 3 includes a piston 31 slidably disposed within the control chamber 1b. The piston 31 is fixedly connected to the piston rod 32. The piston elastic element includes a piston spring 33 disposed between the piston 31 and the pneumatic valve body. The piston spring 33 is located on the side of the piston 31 away from the flow channel chamber 1a, and in this embodiment, it is located above the piston, so that its preload can press the piston to a lower position. The pneumatic valve body is provided with a connecting hole I that connects the flow channel chamber 1a and the control chamber 1b. The piston rod 32 passes through the connecting hole I into the flow channel chamber 1a. The control chamber is a cylindrical chamber, and the piston is a cylindrical piston. A groove is formed on the outer circular sidewall of the piston 31, and a rubber sealing ring is disposed in the groove. The piston moves axially, thereby improving the sealing performance between the piston and the inner wall of the control chamber while satisfying the sliding requirement. During the upward axial movement of the piston driven by the pneumatic control structure, the piston compresses the piston spring. Simultaneously, the piston drives the piston rod to move upward axially, and the lower end of the piston rod separates from the valve assembly, thereby releasing the upper restriction of the valve assembly. Under the action of the valve elastic element, the valve assembly is pushed upward to disconnect the flow channel cavity 1a. When there is a power outage, gas outage, or a failure of the pneumatic control structure, the piston moves downward to reset under the push of the piston spring, and at the same time drives the piston rod downward. The valve assembly is supported by the piston rod and moves downward, thereby opening the flow channel cavity and achieving the purpose of being normally open.

[0023] This invention integrates manual mechanical control and pneumatic automatic control into a single valve structure, eliminating the need for external parallel pipelines, reducing the size and weight of the valve body, and lowering the complexity of the system. It is particularly suitable for applications with limited space and large-diameter requirements.

[0024] Example 2: A large-diameter normally open pneumatic valve, based on Example 1, the pneumatic valve body includes a valve body 11 and a cylinder body 12 connected to each other. A flow passage cavity 1a is opened on the valve body 11, a control cavity 1b is opened on the cylinder body 12, a connection hole I is opened on the valve body 11, a connection port 13 corresponding to the connection hole I is opened on the valve body 11, an end cover 14 is detachably installed on the connection port 13, and a valve assembly 4 is installed on the end cover 14.

[0025] In this embodiment, the valve assembly 4 includes a valve 41 slidably mounted on the end cap 14. The valve elastic element includes a valve spring 42 disposed between the valve 41 and the end cap 14. When there is no external force, the valve spring 42 pre-presses the valve 41 onto the sealing surface 18. The end cap has a cylindrical groove that meets the requirements of the valve assembly, and the valve assembly is slidably mounted in the cylindrical groove. As a further optional solution, the valve slides in conjunction with the inner wall of the cylindrical groove, and the side wall of the valve has a sealing ring that mates with the inner wall of the cylindrical groove. The end cap has an air hole that connects to the cavity where the valve spring is located, so that during the process of the valve being pushed down and reset by the piston rod, the cavity below the valve used to accommodate the valve spring can maintain air pressure balance.

[0026] Furthermore, a partition 15 is fixedly installed in the flow channel cavity 1a, which divides the flow channel cavity 1a into a first chamber 16 and a second chamber 17. The first chamber 16 and the second chamber 17 are connected at the connection port 13. The valve body 11 is provided with an inlet and an outlet that are respectively connected to the first chamber 16 and the second chamber 17. The valve body 11 and the partition 15 at the connection port 13 are respectively provided with sealing surfaces 18. The valve 41 is provided with a sealing ring for sealing with the sealing surface 18. The valve assembly 4 cooperates with the sealing surface 18 to control the communication relationship between the first chamber 16 and the second chamber 17. In the absence of any external operation, the normally open pneumatic valve in this embodiment is in the open state. At this time, the elastic force of the piston spring 33 causes the piston 31 to be located at the lower limit position of the control chamber 1b, the lower end of the piston rod 32 contacts the top of the valve 41, and the pre-tightened elastic force of the piston spring presses the valve 41 down to separate it from the sealing surface 18 of the valve body 11 and the partition 15. At the same time, the valve spring is compressed, and the first chamber 16 and the second chamber 17 of the flow channel chamber 1a are connected, so that the liquid can flow from the inlet to the outlet, realizing the normally open function.

[0027] In addition, both the inlet and outlet of the liquid in this embodiment are equipped with connecting flanges, and the connecting flanges are equipped with sealing rings or sealing gaskets, so as to achieve quick and sealed connection with conventional pipelines.

[0028] In this embodiment, the end cap is threaded onto the connection port. By rotating the end cap, the pre-compression and pre-tightening force of the valve spring can be adjusted. Additionally, the cylinder body is also threaded onto the valve body. During assembly, the valve assembly 4 is first pre-installed on the end cap 14, then the end cap 14 is inserted into the connection port. The pre-tightening force of the valve spring is adjusted, and the sealing performance is checked. The piston assembly 3 is then installed into the cylinder body 12, the piston spring is installed, and finally, the valve body 11 and cylinder body 12 are threaded together. This modular assembly of components is achieved through a rapid assembly process, improving assembly efficiency and reducing complexity.

[0029] Example 3: A large-diameter normally open pneumatic valve, based on Example 2, includes a handle 5 with a handle rod 51. A connecting hole II is provided on the cylinder body 12. The middle part of the handle rod 51 is slidably or threadedly engaged with the connecting hole II. The lower end of the handle rod 51 is movably engaged with the piston rod 32. The upper end of the handle rod 51 is connected to the handle 52. In this example, a mounting hole is provided on the handle. The end of the handle rod 51 passes through the mounting hole and is locked by a set screw threaded onto the handle.

[0030] The piston rod has a groove at its upper end, and the lower end of the handle rod is inserted into the groove of the piston rod. At the same time, the lower end of the handle rod has a T-shaped cross section, which allows the lower end of the handle rod to slide within the groove. The T-shaped end prevents it from coming out of the groove, and it can also drive the piston rod to move axially synchronously when it reaches the limit position, thus meeting the adjustment and reset movement requirements.

[0031] As a further specific implementation, the handle rod has an external thread in the middle and an internal thread on the connecting hole II. The lower end of the handle rod can rotate in the groove at the end of the piston rod. When it needs to be opened manually, the handle rod is rotated by rotating the grip, thereby realizing the axial movement of the handle rod.

[0032] The pneumatic control structure 6 includes a first interface 61 and a second interface 62 opened on the cylinder body 12. The first interface 61 and the second interface 62 are respectively arranged on both sides of the piston 31. The first interface 61 is used to introduce or extract control gas into the control chamber 1b on one side of the piston 31, and the second interface 62 is used to maintain the air pressure balance in the control chamber 1b on the other side of the piston 31.

[0033] As a further specific implementation, the first interface 61 is equipped with an NPT compression fitting, and the second interface 62 is equipped with a silencer. The silencer reduces the noise during gas entry and exit. Sealing rings are provided on connection hole I, connection hole II, connection port 13, and valve 41 to improve the sealing performance of the connection points. In actual use, the NPT compression fitting is connected to the existing pneumatic control pipeline. Under the control of the solenoid valve in the existing pneumatic control pipeline, control gas is introduced or discharged through the NPT compression fitting to achieve the purpose of pneumatically controlling the piston movement.

[0034] In emergency situations such as gas supply failure, power outage, or system malfunction, the operator can manually close the valve. The operator grasps handle 52 and pulls upwards to rotate the lever 51, causing it to move the piston rod and piston assembly upwards. The pulling force generated by the handle overcomes the spring force of the piston spring, causing the valve 41 to lose the support of the piston rod and be pressed against the sealing surface 18 by the valve spring. During manual operation, the air in the control chamber 1b above the piston 31 is compressed and discharged through the second port 61, while air is drawn into the control chamber 1b below the piston through the first port 61, maintaining internal and external pressure balance.

[0035] Once the emergency is over, the operator rotates the handle 52 in the opposite direction to release it. The piston 31 resets under the action of the piston spring 33, and the valve 41 reopens under the action of the valve spring 42, restoring the valve to its safe open state.

[0036] In actual use, the normally open pneumatic valve in the above embodiment is initially in the normally open state: Rotate the handle to the lowest position. The piston moves downward to the lowest position under the force of the piston spring. The valve is pushed to the state of separation from the sealing end face. The valve spring is compressed. At this time, the product is in the closed state.

[0037] During the pneumatic opening and closing of a normally open pneumatic valve: Pneumatic shut-off: Rotate the handle to the lowest position and introduce control gas through the NPT compression fitting at a pressure of 0.4~0.8MPa. The piston and piston rod will be forced upward to the highest position, and the sealing end face of the valve will contact the sealing surface 18 of the valve body to seal. At this time, the product is in the closed state.

[0038] Pneumatic opening: The control gas is released through the NPT compression fitting. The piston moves downward under the force of the piston spring, overcoming the force of the valve spring and pushing the valve downward. The valve sealing face separates from the valve body sealing face, and the whole is in the open state.

[0039] Normally open pneumatic valve during manual opening and closing: Manual closing: Rotate the handle to the highest position. At this time, the handle drives the piston and piston rod to move upward to the highest position. The piston rod separates from the valve. The valve moves upward under the action of the valve piston. The sealing end face of the valve contacts the sealing surface of the valve body. At this time, the valve is in the closed state.

[0040] Manual opening: Rotate the handle to the lowest position. The piston moves downward under the force of the piston spring, overcoming the force of the valve spring and pushing the valve downward. The sealing end face of the valve separates from the sealing surface of the valve body. At this time, the product is in the open state.

[0041] This utility model achieves efficient integration of manual and automatic modes through structural innovation, enabling modular and rapid assembly, significantly improving system reliability and engineering applicability, and has good promotional value.

[0042] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A large-diameter normally open pneumatic valve, characterized in that: The device includes a pneumatic valve body, which has a flow channel cavity (1a) and a control cavity (1b). The pneumatic valve body has an inlet and an outlet, which are connected within the flow channel cavity (1a). A valve assembly (4) is slidably disposed within the flow channel cavity (1a). A valve elastic element is provided between the valve assembly (4) and the pneumatic valve body, providing pre-tightening force to the valve assembly (4). A piston assembly (3) is slidably disposed within the control cavity (1b). One end of the piston assembly (3) penetrates into the flow channel cavity (1a) and its end engages with the valve assembly (4). 3) The other end is engaged with the handle (5) on the pneumatic valve body; a piston elastic element is provided in the control chamber (1b), and the preload provided by the piston elastic element can cause the piston assembly (3) to push the valve assembly (4) to move and compress the valve elastic element, thereby making the flow passage chamber (1a) normally open; the pneumatic valve body is provided with a pneumatic control structure (6) that cooperates with the piston assembly (3). The handle (5) and the pneumatic control structure (6) can both drive the piston assembly (3) to move and compress the piston elastic element, while the valve elastic element resets and pushes the valve assembly (4) to slide and close the flow passage chamber (1a).

2. The large-diameter normally open pneumatic valve according to claim 1, characterized in that: The piston assembly (3) includes a piston (31) slidably disposed in the control chamber (1b). The piston (31) is fixedly connected to the piston rod (32). The piston elastic element includes a piston spring (33) disposed between the piston (31) and the pneumatic valve body. The piston spring (33) is located on the side of the piston (31) away from the flow channel chamber (1a). The pneumatic valve body is provided with a connecting hole I that connects the flow channel chamber (1a) and the control chamber (1b). The piston rod (32) passes through the connecting hole I into the flow channel chamber (1a).

3. The large-diameter normally open pneumatic valve according to claim 2, characterized in that: The pneumatic valve body includes a valve body (11) and a cylinder body (12) connected to each other. A flow channel cavity (1a) is opened on the valve body (11), a control cavity (1b) is opened on the cylinder body (12), a connection hole I is opened on the valve body (11), a connection port (13) corresponding to the connection hole I is opened on the valve body (11), an end cap (14) is detachably installed on the connection port (13), and a valve assembly (4) is installed on the end cap (14).

4. The large-diameter normally open pneumatic valve according to claim 3, characterized in that: A partition (15) is fixedly installed inside the flow channel cavity (1a). The partition (15) divides the flow channel cavity (1a) into a first chamber (16) and a second chamber (17). The first chamber (16) and the second chamber (17) are connected at the connection port (13). The first chamber (16) and the second chamber (17) are respectively connected to the liquid inlet and the liquid outlet. The valve body (11) at the connection port (13) and the partition (15) are respectively provided with sealing surfaces (18). The valve assembly (4) cooperates with the sealing surface (18) to control the communication relationship between the first chamber (16) and the second chamber (17).

5. The large-diameter normally open pneumatic valve according to claim 4, characterized in that: The valve assembly (4) includes a valve (41) slidably disposed on the end cover (14), and the valve elastic element includes a valve spring (42) disposed between the valve (41) and the end cover (14). The valve spring (42) can press the valve (41) against the sealing surface (18), and the preload provided by the valve spring (42) is less than the preload provided by the piston spring (33).

6. The large-diameter normally open pneumatic valve according to claim 5, characterized in that: The handle (5) includes a handle rod (51), a connecting hole II is provided on the cylinder body (12), the middle part of the handle rod (51) is engaged with the connecting hole II, the lower end of the handle rod (51) is movably connected to the piston rod (32), and the upper end of the handle rod (51) is connected to the grip (52).

7. The large-diameter normally open pneumatic valve according to claim 6, characterized in that: The pneumatic control structure (6) includes a first interface (61) and a second interface (62) on the cylinder (12). The first interface (61) and the second interface (62) are respectively located on both sides of the piston (31). The first interface (61) is used to introduce or extract control gas into the control chamber (1b) on one side of the piston (31), and the second interface (62) is used to maintain the air pressure balance in the control chamber (1b) on the other side of the piston (31).

8. The large-diameter normally open pneumatic valve according to claim 7, characterized in that: The first interface (61) is equipped with an NPT ferrule connector, and the second interface (62) is equipped with a silencer.

9. The large-diameter normally open pneumatic valve according to claim 8, characterized in that: Sealing rings are provided on the connecting hole I, connecting hole II, connecting port (13), and valve (41).

10. The large-diameter normally open pneumatic valve according to any one of claims 4 to 9, characterized in that: Both the inlet and outlet are equipped with connecting flanges.

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