Stainless steel nuclear grade direct stroke piston pneumatic actuator

Abstract

The application discloses a stainless steel nuclear-grade straight stroke piston type pneumatic actuator, which comprises a cylinder body, an upper cylinder cover, a lower cylinder cover, a piston, a piston rod, an open-close nut device, a hand wheel and a position indicating device, the upper cylinder cover is connected with the first end of the cylinder body through a mortise and tenon joint, the lower cylinder cover is connected with the second end of the cylinder body through a mortise and tenon joint, the piston rod passes through the upper cylinder cover, the piston and the lower cylinder cover, the open-close nut device is arranged on the part of the piston rod located outside the cylinder body and close to the upper cylinder cover in a circumferential direction, the end of the open-close nut device, which is far away from the upper cylinder cover, is connected with the hand wheel in a circumferential direction, and the end of the piston rod, which is close to the upper cylinder cover, is further connected with the position indicating device. The application solves the stress deformation under high-temperature and earthquake working conditions, avoids the screw thread from being locked to cause the actuator to be unable to be disassembled, and saves the arrangement space.

Description

Technical Field

[0001] This invention relates to the field of valve actuator technology, and in particular to a stainless steel nuclear-grade linear piston pneumatic actuator. Background Technology

[0002] In a pneumatic system, a pneumatic actuator is a transmission device that converts the energy of compressed air into mechanical energy to achieve linear, rotary, or oscillating motion. Pneumatic actuators mainly come in three forms: diaphragm type, cylinder type, and oscillating type. They are simple in structure, low in manufacturing cost, easy to maintain, operate at low pressure, move quickly, and their output force and speed are easily adjustable.

[0003] In recent years, pneumatic technology has combined the advantages of electronic, hydraulic, mechanical, and electrical transmission technologies, resulting in its exceptionally rapid development. With the rapid advancement of modern industrial automation, instrumentation and automation equipment is widely used in pipeline control systems to achieve automated control. In the event of emergencies such as short-term power outages at the pipeline site, pneumatic actuators with manual / pneumatic switching capabilities can be selected. In the event of power outages or malfunctions of solenoid valves and their control circuits, the operating handle can be easily turned to quickly switch between pneumatic and manual operation, ensuring normal pipeline operation and preventing accidents.

[0004] Nuclear-grade valves used in nuclear power systems require all parts to be made of stainless steel because their pneumatic actuators need to operate in environments with certain levels of radioactivity and corrosion. Furthermore, given these special environmental conditions, they must be designed for rapid inspection, replacement, and disassembly to minimize radiation exposure for maintenance personnel. However, current cylinder structures on the market primarily use a cylinder body connected to upper and lower cylinder heads with tie rods. When both the tie rods and nuts are made of stainless steel, the tie rods and nuts are prone to seizing.

[0005] Therefore, those skilled in the art are dedicated to providing a stainless steel nuclear-grade linear piston pneumatic actuator that achieves manual-pneumatic switching through a clutch-type manual operation and a lever-less open-loop tenon structure, and can prevent misoperation during manual operation. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is how to provide a pneumatic actuator that can quickly switch between manual and pneumatic operation and prevent manual misoperation.

[0007] To achieve the above objectives, the present invention provides a stainless steel nuclear-grade linear piston pneumatic actuator, comprising a cylinder body, an upper cylinder head, a lower cylinder head, a piston, a piston rod, an opening and closing nut device, a handwheel, and a position indicator device. The upper cylinder head is tenon-jointed to a first end of the cylinder body, and the lower cylinder head is tenon-jointed to a second end of the cylinder body. The piston is located within the cylinder body, and the piston rod passes through the upper cylinder head, piston, and lower cylinder head. The piston and piston rod are fixedly connected. The portion of the piston rod outside the cylinder body near the upper cylinder head has an external thread. The portion of the piston rod outside the cylinder body near the upper cylinder head has the opening and closing nut device circumferentially arranged. The end of the opening and closing nut device away from the upper cylinder head is circumferentially connected to the handwheel. The opening and closing nut device is configured to engage or disengage with the external thread of the piston rod. The end of the piston rod near the upper cylinder head is also connected to the position indicator device, which is configured to indicate the stroke position of the piston rod.

[0008] Furthermore, the opening and closing nut device includes a thrust pin bearing, a transmission sleeve, a locking rod, a spring seat, a spring, an opening and closing rod, an opening and closing disc, an opening and closing nut, and a four-opening ring. The transmission sleeve is connected to the upper cylinder head through the thrust pin bearing. The locking rod and the opening and closing rod are located at both ends of the piston rod in the circumferential direction. One end of the locking rod is provided with the spring seat. The transmission sleeve has a locking rod hole for accommodating the spring seat. The spring is provided between the spring seat and the opening and closing disc. The opening and closing disc is connected to the opening and closing nut. The end of the opening and closing disc is also provided with the four-opening ring. The handwheel is sleeved on the four-opening ring.

[0009] Furthermore, it also includes an upper bushing, which is sleeved on the piston rod and embedded in the upper cylinder head and the transmission sleeve.

[0010] Furthermore, the position indicating device includes an indicator rod, an indicator, a closed indicator block, an open indicator block, and a protective cover. The indicator rod is fixed to the end of the piston rod, the indicator is disposed on the indicator rod, the protective cover is disposed on the outside of the indicator rod, and the closed indicator block and the open indicator block are disposed on the protective cover.

[0011] Furthermore, the piston rod is connected to a saddle-shaped quick-release anti-rotation component at the end near the lower cylinder head, and the other end of the saddle-shaped quick-release anti-rotation component is configured to connect to the valve stem.

[0012] Furthermore, the piston rod is rotatably connected to the saddle-shaped clamp quick-release anti-rotation component, and the valve rod is fixedly connected to the saddle-shaped clamp quick-release anti-rotation component.

[0013] Furthermore, a bracket is provided on the outer side of the saddle-shaped anti-rotation component, through which the valve stem passes.

[0014] Furthermore, a nut is provided on the piston rod between the piston and the lower cylinder head, and the nut is fitted to the piston.

[0015] Furthermore, sealing rings are respectively provided between the piston and the inner wall of the cylinder, between the upper cylinder head and the inner wall of the cylinder, and between the lower cylinder head and the inner wall of the cylinder.

[0016] Furthermore, the tenon and mortise structure between the upper cylinder head and the cylinder body, and between the lower cylinder head and the cylinder body, is provided with an open ring.

[0017] The present invention has at least the following beneficial technical effects:

[0018] 1. The stainless steel nuclear-grade linear piston pneumatic actuator provided by this invention uses a tenon and mortise structure to connect the cylinder body and cylinder head. Compared with the tie rod connection mechanism, this solves the stress deformation problem under high temperature conditions and seismic conditions, avoids thread seizure leading to disassembly, and also avoids safety accidents caused by tie rod corrosion and breakage in corrosive environments. The tenon and mortise connection makes the device more compact and saves layout space.

[0019] 2. The stainless steel nuclear-grade linear piston pneumatic actuator provided by the present invention realizes the switching between pneumatic and manual operation through the opening and closing nut device, and the opening and closing is achieved in the radial direction of the piston rod, which reduces the height of the pneumatic actuator and makes the manual-pneumatic switching safe and convenient.

[0020] 3. The stainless steel nuclear-grade linear piston pneumatic actuator provided by this invention has a position indicator that can adjust the indication according to the formation of different equipment, and fine-tune the errors in the assembly and production process, thus solving the problem of inaccurate indication.

[0021] 4. The stainless steel nuclear-grade linear piston pneumatic actuator provided by this invention adopts an integrated piston rod design, which ensures the accuracy of output force and piston formation, and allows the internal components of the cylinder to be removed at one time, facilitating the replacement of seals and the inspection of internal components, thus saving maintenance time.

[0022] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the stainless steel nuclear-grade linear piston pneumatic actuator provided in an embodiment of the present invention;

[0024] Figure 2 This is a three-dimensional schematic diagram of a stainless steel nuclear-grade linear piston pneumatic actuator provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the overall structure of the opening and closing nut device provided in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the switching process of the opening and closing nut device provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the position indicator device provided in an embodiment of the present invention.

[0028] In the picture,

[0029] 1-Cylinder block, 2-Piston, 31-Upper cylinder head, 32-Lower cylinder head, 4-Opening ring, 5-Opening and closing nut, 6-Opening and closing nut operating mechanism, 62-Opening and closing rod, 63-Spring, 64-Spring seat, 65-Locking rod, 7-Handwheel, 8-Four-ring open, 9-Indicator, 10-Position indicating device, 101-Open indicator block, 102-Closed indicator block, 103-Screw, 104-Indicator rod, 105-Protective cover, 11-Bracket, 12-Saddle-shaped clamp quick-release anti-rotation component, 13-Piston rod, 14-Transmission sleeve, 15-Adjusting sleeve, 16-Opening and closing disc, 17-End cap, 18-Thrust pin bearing, 19-Upper bushing, 20-Compression spring, 21-Nut. Detailed Implementation

[0030] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0031] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0032] This invention provides a stainless steel nuclear-grade linear piston pneumatic actuator, such as... Figure 1 and Figure 2 As shown, the pneumatic actuator of the present invention includes a cylinder body 1, a piston 2, an upper cylinder head 31, a lower cylinder head 32, a piston rod 13, a handwheel 7, a saddle-shaped clamp quick-release anti-rotation component 12, an opening and closing nut device, and a position indicator device 10. The cylinder body 1, the upper cylinder head 31, and the lower cylinder head 32 are connected to form a sealed cylinder. The piston 2 is located inside the cylinder body 1. The piston rod 13 passes through the upper cylinder head 31, the piston 2, and the lower cylinder head 32 in sequence, and the piston 2 is fixed on the piston rod 13, so that the piston 2 moves up and down with the piston rod 13.

[0033] In this invention, the upper cylinder head 31 and the cylinder body 1, and the lower cylinder head 32 and the cylinder body 1, are connected by mortise and tenon joints. This mortise and tenon connection makes the cylinder structure compact, reducing the space occupied. Furthermore, it reduces deformation during vibration under anti-vibration conditions, avoids the seizing phenomenon present in threaded connections, and facilitates disassembly and maintenance. Specifically, as... Figure 1 As shown in detailed drawing I, the upper cylinder head 31 and lower cylinder head 32 are provided with a variable diameter structure near the middle position on the circumference, which matches the inner wall of the cylinder body 1, so that the upper cylinder head 31 and lower cylinder head 32 fit snugly against the cylinder body 1; as detailed... Figure II As shown, an opening ring 4 is provided at the end of the upper cylinder head 31 and the lower cylinder head 32 away from the piston 2. Grooves are formed on the inner wall of the cylinder body 1 and at the edges of the upper cylinder head 31 and the lower cylinder head 32. The opening ring 4 is placed in the groove, engaging the upper cylinder head 31 with the cylinder body 1 and the lower cylinder head 32 with the cylinder body 1. By removing the opening ring 4, the upper cylinder head 31 and the lower cylinder head 32 can be removed from the cylinder body 1. See details... Figure II As shown, a pressure strip is also provided on the outside of the open ring 4 to encapsulate the slotted part.

[0034] To improve the sealing effect, sealing rings are provided between the inner wall of the upper cylinder head 31 and the inner wall of the cylinder body 1, between the inner wall of the lower cylinder head 32 and the inner wall of the cylinder body 1, and between the piston 2 and the inner wall of the cylinder body 1, to ensure that the gas drives the piston 2.

[0035] The piston rod 13 can be segmented with external threads as needed to connect with nuts. In this embodiment, the portion of the piston rod 13 located between the piston 2 and the lower cylinder head 32 has external threads, on which a nut 21 engages. The nut 21 is in close contact with the piston 2, thus limiting the piston 2 and preventing it from moving too far, which could damage the cylinder. It also prevents the piston 2 from slipping off the piston rod 13 when the valve is disassembled.

[0036] The piston rod 13 is connected to a saddle-shaped quick-release anti-rotation component 12 at the end near the lower cylinder head 32. The other side of the saddle-shaped quick-release anti-rotation component 12 is connected to the valve stem, thus connecting the piston rod 13 and the valve stem. A bracket 11 is provided on the outside of the saddle-shaped quick-release anti-rotation component 12 to protect it, and the valve stem passes through the bracket 11.

[0037] In this embodiment, the saddle-shaped quick-release anti-rotation component 12 has a U-shaped structure. One of its two sides is rotatably connected to the end of the piston rod 13. Specifically, a hole can be opened on this side, and a groove and a boss can be provided circumferentially on the piston rod 13 so that the groove matches the opening. This allows the piston rod 13 to rotate relative to this side while restricting its axial movement relative to this side. The valve stem is fixedly connected to the other side of the U-shape, specifically by bolts. Thus, the saddle-shaped quick-release anti-rotation component 12 can both prevent the valve stem from rotating and enable quick assembly and disassembly.

[0038] The opening and closing nut device is used to switch the pneumatic actuator of the present invention between manual and pneumatic operation. The opening and closing nut device is located on the side of the piston rod 13 outside the upper cylinder head 31, and the piston rod 13 is provided with external threads. The main components of the opening and closing nut device are the opening and closing nut operating mechanism 6, the opening and closing nut 5, and the opening and closing disc 16. When the opening and closing nut 5 is engaged with the thread of the piston rod 13, manual operation of the actuator can be realized. When the opening and closing nut 5 is disengaged from the thread of the piston rod 13, pneumatic control of the actuator is performed.

[0039] Specifically, such as Figure 3 and Figure 4 As shown, the opening and closing nut device consists of a thrust pin bearing 18, a transmission sleeve 14, a locking rod 65, a spring seat 64, a spring 63, an opening and closing rod 62, an opening and closing disc 16, an opening and closing nut 5, and a four-ring 8. The transmission sleeve 14 is connected to the upper cylinder head 31 via the thrust pin bearing 18 to reduce the friction between the transmission sleeve 14 and the upper cylinder head 31. The locking rod 65 and the opening and closing rod 62 are located at both ends of the piston rod 13 circumferentially. One end of the locking rod 65 is provided with a spring seat 64, and the transmission sleeve 14 has a locking rod hole to accommodate the spring seat 64. A spring 63 is provided between the spring seat 64 and the opening and closing disc 16, and the opening and closing disc 16 is connected to the opening and closing nut 5. When the spring seat 64 is in the locking rod hole, rotating the opening and closing rod 62 counterclockwise by a certain angle will cause the opening and closing plate 16 to disengage the opening and closing nut 5 from the piston rod 13, and the actuator will switch to pneumatic operation. When the spring seat 64 is disengaged from the locking rod hole, rotating the opening and closing rod 62 clockwise by the same angle will cause the opening and closing plate 16 to engage the opening and closing nut 5 with the piston rod 13, and the actuator will switch to manual operation.

[0040] The end of the opening and closing plate 16 is also provided with a four-ring 8, which can restrict the axial movement of the opening and closing plate 16 along the piston rod 13. The handwheel 7 is sleeved on the four-ring 8. In manual operation mode, the piston rod 13 can be raised and lowered by operating the handwheel 7.

[0041] like Figure 2As shown, an adjusting sleeve 15 is provided on the outside of the transmission sleeve 14, and an end cap 17 is provided on the outside of the four-ring 8. The adjusting sleeve 15 and the end cap 17 encapsulate the opening and closing nut device as a whole, realizing a compact connection of the device.

[0042] When the actuator is switched to manual operation, the handwheel 7 is turned to drive the opening and closing nut device to rotate as a whole. The opening and closing nut 5 rotates relative to the piston rod 13, and the piston rod 13 is raised and lowered under the drive of the opening and closing nut 5.

[0043] To facilitate the lifting and lowering of the piston rod 13, the pneumatic actuator of the present invention is also provided with an upper bushing 19, which is sleeved on the piston rod 13 and embedded in the upper cylinder head 31 and the transmission sleeve 14. To achieve cylinder sealing, a sealing ring is also provided between the upper bushing 19 and the upper cylinder head 31.

[0044] like Figure 5 As shown, the position indicating device 10 is used to indicate the stroke of the piston rod 13. Specifically, it consists of an indicating rod 104, an indicator 9, a closed indicating block 102, an open indicating block 101, and a protective cover 105. The indicating rod 104 is fixed to the end of the piston rod 13. The indicator 9 is located on the indicating rod 104. The protective cover 105 is located on the outside of the indicating rod 104. The closed indicating block 102 and the open indicating block 101 are located on the protective cover 105 and are fixed to the protective cover 105 by screws 103. The position indicating device 10 is an adjustable mechanism. The indicating height can be adjusted by adjusting the indicator 9, and the stroke range of the equipment can be adjusted by adjusting the open indicating block 101 and the closed indicating block 102. This allows for fine-tuning of errors during assembly and production, and the screws 103 prevent movement caused by external vibrations, thus solving the problem of inaccurate indication.

[0045] The linear piston pneumatic actuator of this invention can be a single-acting actuator or a double-acting actuator. When it is a single-acting actuator, it is further divided into normally closed and normally open types; for example... Figure 1 The diagram shows a normally closed piston type, with a compression spring 20 fitted on the piston rod 13 between the piston 2 and the upper cylinder head 31. In the normally open type, a compression spring 20 is fitted on the piston rod 13 between the piston 2 and the lower cylinder head 32. When the piston 2 moves up and down with the piston rod 13, the compression spring 20 provides a restoring force to the piston 2. Correspondingly, intake or exhaust ports are provided on the lower cylinder head 32 and the upper cylinder head 31. In the case of a double-acting actuator, springs are not required on either side of the piston 2. Correspondingly, intake ports are provided on both the upper cylinder head 31 and the lower cylinder head 32. The piston 2 moves up and down by alternating intake and exhaust through the upper and lower cylinder heads. The intake ports can also be used for exhaust.

[0046] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A stainless steel nuclear-grade linear piston pneumatic actuator, characterized in that, The system includes a cylinder block, an upper cylinder head, a lower cylinder head, a piston, a piston rod, a nut and bolt assembly, a handwheel, and a position indicator. The upper cylinder head is tenon-jointed to the first end of the cylinder block, and the lower cylinder head is tenon-jointed to the second end of the cylinder block. An opening ring is provided in the tenon-joint structure between the upper and lower cylinder heads. A variable-diameter structure matching the inner wall of the cylinder block is provided near the center of the circumference of the upper and lower cylinder heads, allowing them to fit snugly against the cylinder block. The opening ring is located at the end of the upper and lower cylinder heads away from the piston. Grooves are formed on the inner wall of the cylinder block and at the edges of the upper and lower cylinder heads, with the opening ring positioned within these grooves. A pressure strip is also provided on the outer side of the opening ring. The piston is located within the cylinder block, and the piston rod passes through the upper cylinder head, piston, and lower cylinder head. The piston is fixedly connected to the piston rod. The portion of the piston rod located outside the cylinder body near the upper cylinder head has external threads. The portion of the piston rod located outside the cylinder body near the upper cylinder head has the opening and closing nut device circumferentially connected. The end of the opening and closing nut device away from the upper cylinder head is circumferentially connected to the handwheel. The opening and closing nut device is configured to engage or disengage with the external threads of the piston rod. The end of the piston rod near the upper cylinder head is also connected to the position indicator device, which is configured to indicate the stroke position of the piston rod. The end of the piston rod near the lower cylinder head is connected to a saddle-shaped quick-release anti-rotation component. The other end of the saddle-shaped quick-release anti-rotation component is configured to connect to a valve stem. The piston rod is rotatably connected to the saddle-shaped quick-release anti-rotation component, and the valve stem is fixedly connected to the saddle-shaped quick-release anti-rotation component.

2. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 1, characterized in that, The opening and closing nut device includes a thrust pin bearing, a transmission sleeve, a locking rod, a spring seat, a spring, an opening and closing rod, an opening and closing disc, an opening and closing nut, and a four-opening ring. The transmission sleeve is connected to the upper cylinder head through the thrust pin bearing. The locking rod and the opening and closing rod are located at both ends of the piston rod circumferentially. One end of the locking rod is provided with the spring seat. The transmission sleeve has a locking rod hole for accommodating the spring seat. The spring is provided between the spring seat and the opening and closing disc. The opening and closing disc is connected to the opening and closing nut. The end of the opening and closing disc is also provided with the four-opening ring. The handwheel is sleeved on the four-opening ring.

3. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 2, characterized in that, It also includes an upper bushing, which is fitted onto the piston rod and embedded in the upper cylinder head and the transmission sleeve.

4. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 1, characterized in that, The position indicating device includes an indicator rod, an indicator, a closed indicator block, an open indicator block, and a protective cover. The indicator rod is fixed to the end of the piston rod, the indicator is located on the indicator rod, the protective cover is located on the outside of the indicator rod, and the closed indicator block and the open indicator block are located on the protective cover.

5. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 1, characterized in that, The outer side of the saddle-shaped anti-rotation component is also provided with a bracket, through which the valve stem passes.

6. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 1, characterized in that, The piston rod is provided with a nut between the piston and the lower cylinder head, and the nut is fitted to the piston.

7. The stainless steel nuclear-grade linear piston pneumatic actuator as described in claim 1, characterized in that, A sealing ring is provided between the piston and the inner wall of the cylinder, between the upper cylinder head and the inner wall of the cylinder, and between the lower cylinder head and the inner wall of the cylinder.

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