Limiting protection device of valve actuator

Abstract

The invention relates to the related technical field of valve actuators, in particular to a limiting protection device of a valve actuator, which comprises an actuator, a switching mechanism is arranged on the upper surface of a worm gear, and a limiting mechanism is arranged on the outer side surface of a rotating shaft. Through the arrangement of a limiting mechanism, during use, a rotating shaft is rotated, a rotating plate is driven to rotate, a movable rod moves towards the center along with rotation of the rotating plate, a second connecting block and a trapezoidal block are driven to move towards the center together, the purpose of shrinking the trapezoidal block is achieved, and therefore the valve plate can be rotated at will; the rotating shaft is reversely rotated, so that the trapezoidal block moves towards the outer side and is clamped into the trapezoidal groove of the shaft sleeve, the valve plate does not continue to rotate any more, the maximum opening degree state is kept, the flow control precision of a system is improved, the equipment maintenance cost and the safety production risk are reduced, and the production efficiency is improved; and the stability of the whole technological process and the product quality are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field related to valve actuators, and in particular to a limit protection device for a valve actuator. Background Art

[0002] A valve actuator, also known as a valve driver, is a device that converts a control signal into a mechanical displacement. It is mainly used to drive a valve to open, close or adjust. Its main function is to accurately control the opening of the valve according to the instructions of the control system to achieve the flow, pressure and direction control of the medium in the pipeline, such as liquid, gas, steam, etc. It is widely used in petroleum, chemical, electric power, metallurgy, light industry, environmental protection and other industries. It is an indispensable part of industrial automation control systems. Therefore, a limit protection device for valve actuators is particularly needed.

[0003] When using existing valve actuators, the valve plate has no limit protection device and is prone to shifting position during operation, resulting in the valve being unable to accurately reach the preset opening, affecting the flow control accuracy of the system, and may even cause medium leakage or system shutdown, thereby increasing equipment maintenance costs and production safety risks, and resulting in extended operation response time, which reduces production efficiency, further affecting the stability of the overall process and product quality. Summary of the invention

[0004] The object of the present invention is to provide a limit protection device for a valve actuator to solve the problem that the existing valve actuator proposed in the above background technology, when in use, because the valve plate has no limit protection device, it is easy to shift the position during operation, resulting in the valve being unable to accurately reach the preset opening, affecting the flow control accuracy of the system, and may even cause medium leakage or system shutdown, thereby increasing equipment maintenance costs and production safety risks, and resulting in prolonged operation response time, resulting in reduced production efficiency, further affecting the stability of the overall process flow and the quality of the product.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a limit protection device for a valve actuator, comprising an actuator, an indicator chip is fixedly connected to the inner surface of the actuator, a connecting piece is fixedly connected to one side surface of the indicator chip, a control board is fixedly connected to one side surface of the connecting piece, a control cabinet is fixedly connected to the inner surface of the actuator, a motor is fixedly connected to the inner surface of the actuator, a worm is fixedly connected to one side surface of the motor, a valve body is fixedly connected to the outer surface of the actuator, a worm groove is provided on the outer surface of the valve body, a worm wheel is meshed on the outer surface of the worm, a switching mechanism is provided on the upper surface of the worm wheel, and the switching mechanism comprises a first connecting block, a switching sleeve, A connecting groove, a block, a slider, a manual lever, a spring, a rotating shaft, a slide groove, a switching block, a switching shaft, a clamping block, a switching lever and a clamping groove; a limiting mechanism is arranged on the outer surface of the rotating shaft; an upper shaft valve is fixedly connected to the outer surface of the rotating shaft; a connecting nail is slidably connected to the inner surface of the upper shaft valve; a locking block is rotatably connected to the outer surface of the connecting nail; a lower shaft valve is slidably connected to the outer surface of the connecting nail; a lower shaft valve is fixedly connected to the outer surface of the connecting nail; a butterfly valve is fixedly connected to the lower surface of the support frame; a connecting port is provided on the outer surface of the butterfly valve; a valve plate is fixedly connected to the lower surface of the rotating shaft; a hand wheel is fixedly connected to the upper surface of the rotating shaft; a handle is fixedly connected to the upper surface of the hand wheel; The limiting mechanism includes a rotating plate, a movable opening, a movable rod, a second connecting block, a trapezoidal block, a sleeve and a trapezoidal groove. The outer surface of the rotating shaft is fixedly connected to the rotating plate, the outer surface of the rotating plate is provided with a movable opening, the inner surface of the movable opening is slidably connected to the movable rod, the outer surface of the movable rod is fixedly connected to the second connecting block, the upper surface of the second connecting block is fixedly connected to the trapezoidal block, the outer surface of the rotating shaft is fixedly connected to the sleeve, and the inner surface of the sleeve is provided with a trapezoidal groove.

[0006] Preferably, the movable openings are provided in multiple groups on the outer surface of the rotating plate, and the movable openings are symmetrically arranged with respect to the central axis of the rotating plate.

[0007] Preferably, the outer wall surface size of the trapezoidal block matches the inner wall surface size of the trapezoidal groove, and the trapezoidal grooves are provided in multiple groups on the inner surface of the sleeve.

[0008] Preferably, the upper surface of the upper surface of the worm gear is fixedly connected with a first connecting block, the outer surface of the first connecting block is slidably connected with a switching sleeve, the outer surface of the switching sleeve is provided with a connecting groove, the upper surface of the switching sleeve is fixedly connected with a block, the inner surface of the switching sleeve is fixedly connected with a sliding block, the outer surface of the block is slidably connected with a manual rod, the lower surface of the manual rod is fixedly connected with a spring, the inner surface of the switching sleeve is slidably connected with a rotating shaft, the outer surface of the rotating shaft is provided with a sliding groove, the lower surface of the switching sleeve is rotatably connected with a switching block, one side surface of the switching block is fixedly connected with a switching shaft, the outer surface of the switching shaft is fixedly connected with a clamping block, the outer surface of the clamping block is slidably connected with a switching rod, and the inner surface of the switching rod is provided with a clamping groove.

[0009] Preferably, the first connecting blocks are provided in multiple groups on the upper surface of the worm gear, and the connecting grooves are provided in multiple groups on the outer surface of the switching sleeve.

[0010] Preferably, two groups of the blocks are provided on the lower surface of the switching sleeve, and multiple groups of the sliding blocks are provided on the inner surface of the switching sleeve.

[0011] Preferably, the slide groove is provided with a plurality of groups on the outer surface of the slide groove, and the size of the outer wall surface of the clamping block is consistent with the size of the inner wall surface of the clamping groove.

[0012] Preferably, the connecting pieces are provided in multiple groups on one side surface of the indicating chip, and the size of the outer wall surface of the worm is consistent with the size of the inner wall surface of the worm groove.

[0013] Preferably, the connecting pins are provided in multiple groups on the inner surface of the upper shaft valve, and the supporting frames are provided in multiple groups on the outer surface of the lower shaft valve.

[0014] Preferably, the connection ports are provided in multiple groups on the outer surface of the butterfly valve, and the size of the inner wall surface of the butterfly valve matches the size of the outer wall surface of the valve plate.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the limit protection device of the valve actuator, through the setting of the limit mechanism, when in use, rotates the rotating shaft to drive the rotating plate to rotate, and the movable rod moves toward the center as the rotating plate rotates, driving the second connecting block and the trapezoidal block to move toward the center together, thereby achieving the purpose of shrinking the trapezoidal block, so that the valve plate can be rotated at will, and when the valve plate needs to be fixed at the maximum opening, the rotating shaft is rotated in the opposite direction to make the trapezoidal block move outward, thereby engaging into the trapezoidal groove of the shaft sleeve, and the valve plate no longer continues to rotate and maintains the maximum opening state, thereby improving the flow control accuracy of the system, reducing equipment maintenance costs and production safety risks, and at the same time reducing the operation response time, improving production efficiency, and further improving the stability of the overall process flow and the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the side appearance structure of the present invention; Figure 2 This is a schematic diagram of the structure of the indicator chip and the connecting piece cooperating with each other in the present invention; Figure 3 This is a schematic diagram of the structure of the hand wheel and the handle cooperating with each other in the present invention; Figure 4 It is a schematic diagram of the structure of the worm and the worm wheel cooperating with each other in the present invention; Figure 5 This is a schematic diagram of the structure of the first connecting block and the switching sleeve cooperating with each other in the present invention; Figure 6 This is a schematic diagram of the structure of the upper shaft valve and the lower shaft valve cooperating with each other in the present invention; Figure 7 This is a schematic diagram of the structure of the trapezoidal block and the shaft sleeve cooperating with each other in the present invention; Figure 8 It is a schematic diagram of the structure of the butterfly valve and the valve plate cooperating with each other in the present invention.

[0017] In the figure: 1, actuator; 2, indicator chip; 3, connecting piece; 4, control board; 5, control cabinet; 6, motor; 7, worm; 8, valve body; 9, worm groove; 10, worm wheel; 11, switching mechanism; 1101, first connecting block; 1102, switching sleeve; 1103, connecting groove; 1104, stopper; 1105, slider; 1106, manual lever; 1107, spring; 1108, rotating shaft; 1109, slide groove; 1110, switching block; 1111, switching shaft ; 1112, block; 1113, switching rod; 1114, slot; 12, limit mechanism; 1201, rotating plate; 1202, movable port; 1203, movable rod; 1204, second connecting block; 1205, trapezoidal block; 1206, shaft sleeve; 1207, trapezoidal slot; 13, upper shaft valve; 14, connecting nail; 15, locking block; 16, lower shaft valve; 17, support frame; 18, butterfly valve; 19, connecting port; 20, valve plate; 21, handwheel; 22, handle. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-8The present invention provides a technical solution: a limit protection device for a valve actuator, comprising an actuator 1, an indicator chip 2 is fixedly connected to the inner surface of the actuator 1, a connecting piece 3 is fixedly connected to one side surface of the indicator chip 2, a control board 4 is fixedly connected to one side surface of the connecting piece 3, a control cabinet 5 is fixedly connected to the inner surface of the actuator 1, a motor 6 is fixedly connected to the inner surface of the actuator 1, a worm 7 is fixedly connected to one side surface of the motor 6, a valve body 8 is fixedly connected to the outer surface of the actuator 1, a worm groove 9 is provided on the outer surface of the valve body 8, a worm wheel 10 is meshed on the outer surface of the worm 7, a switching mechanism 11 is provided on the upper surface of the worm wheel 10, and the switching mechanism 11 comprises a first connecting block 1101, a switching sleeve 1102, a connecting groove 1103, a stopper 1104, a slider 1105, a manual lever 1106, and a spring 1107. , a rotating shaft 1108, a slide groove 1109, a switching block 1110, a switching shaft 1111, a clamping block 1112, a switching rod 1113 and a clamping groove 1114, a limiting mechanism 12 is provided on the outer surface of the rotating shaft 1108, an upper shaft valve 13 is fixedly connected to the outer surface of the rotating shaft 1108, a connecting nail 14 is slidably connected to the inner surface of the upper shaft valve 13, a locking block 15 is rotatably connected to the outer surface of the connecting nail 14, a lower shaft valve 16 is slidably connected to the outer surface of the connecting nail 14, a supporting frame 17 is fixedly connected to the outer surface of the lower shaft valve 16, a butterfly valve 18 is fixedly connected to the lower surface of the supporting frame 17, a connecting port 19 is provided on the outer surface of the butterfly valve 18, a valve plate 20 is fixedly connected to the lower surface of the rotating shaft 1108, a hand wheel 21 is fixedly connected to the upper surface of the rotating shaft 1108, and a handle 22 is fixedly connected to the upper surface of the hand wheel 21; The limiting mechanism 12 includes a rotating plate 1201, a movable opening 1202, a movable rod 1203, a second connecting block 1204, a trapezoidal block 1205, a sleeve 1206 and a trapezoidal groove 1207. The outer surface of the rotating shaft 1108 is fixedly connected with the rotating plate 1201, the outer surface of the rotating plate 1201 is provided with a movable opening 1202, the inner surface of the movable opening 1202 is slidably connected with the movable rod 1203, the outer surface of the movable rod 1203 is fixedly connected with the second connecting block 1204, the upper surface of the second connecting block 1204 is fixedly connected with the trapezoidal block 1205, the outer surface of the rotating shaft 1108 is fixedly connected with the sleeve 1206, the inner surface of the sleeve 1206 is provided with a trapezoidal groove 1207, and the movable plate 1201, the movable opening 1202, the movable opening 1202, the movable rod 1203, the outer surface of the movable rod 1203 is fixedly connected with the second connecting block 1204, the upper surface of the second connecting block 1204 is fixedly connected with the trapezoidal block 1205, the outer surface of the rotating shaft 1108 is fixedly connected with the sleeve 1206, the inner surface of the sleeve 1206 is provided with a trapezoidal groove 1207, 1202, movable rod 1203, second connecting block 1204, trapezoidal block 1205, shaft sleeve 1206 and trapezoidal groove 1207 are arranged. When in use, the rotating shaft 1108 is rotated, 1108 drives the rotating plate 1201 to rotate, and the movable rod 12039 moves toward the center as the rotating plate 1201 rotates, driving the second connecting block 1204 and the trapezoidal block 1205 to move toward the center together, so as to achieve the purpose of contracting the trapezoidal block 1205, so that the valve plate 20 can be rotated at will. When it is necessary to fix the valve plate 20 at the maximum opening, the rotating shaft 1108 is rotated in the opposite direction, so that the trapezoidal block 1205 moves outward, thereby engaging into the trapezoidal groove 1207 of the shaft sleeve 1206, and the valve plate 20 no longer rotates and maintains the maximum opening state.

[0020] Furthermore, multiple groups of movable openings 1202 are arranged on the outer surface of the rotating plate 1201, and the movable openings 1202 are symmetrically arranged with respect to the central axis of the rotating plate 1201. Through the arrangement of the movable openings 1202, when in use, the rotating plate 1201 rotates, changing the position of the movable openings 1202, thereby giving power to the movable rod 1203, driving the second connecting block 1204 and the trapezoidal block 1205 to move toward the center together, thereby achieving the purpose of controlling the movement of the trapezoidal block 1205.

[0021] Furthermore, the outer wall surface size of the trapezoidal block 1205 is consistent with the inner wall surface size of the trapezoidal groove 1207. There are multiple groups of trapezoidal grooves 1207 on the inner surface of the sleeve 1206. Through the arrangement of the trapezoidal block 1205 and the trapezoidal grooves 1207, when in use, when the trapezoidal block 1205 is engaged into the trapezoidal groove 1207 of the sleeve 1206, the valve plate 20 no longer rotates, thereby maintaining the maximum opening state.

[0022] Further, the upper surface of the upper surface of the worm gear 10 is fixedly connected with a first connecting block 1101, the outer surface of the first connecting block 1101 is slidably connected with a switching sleeve 1102, the outer surface of the switching sleeve 1102 is provided with a connecting groove 1103, the upper surface of the switching sleeve 1102 is fixedly connected with a stopper 1104, the inner surface of the switching sleeve 1102 is fixedly connected with a slider 1105, the outer surface of the stopper 1104 is slidably connected with a manual rod 1106, the lower surface of the manual rod 1106 is fixedly connected with a spring 1107, the inner surface of the switching sleeve 1102 is slidably connected with a rotating shaft 1108, and the outer surface of the rotating shaft 1108 is fixedly connected with a spring 1107. A sliding groove 1109 is provided on the side surface, a switching block 1110 is rotatably connected to the lower surface of the switching sleeve 1102, a switching shaft 1111 is fixedly connected to one side surface of the switching block 1110, a clamping block 1112 is fixedly connected to the outer surface of the switching shaft 1111, a switching rod 1113 is slidably connected to the outer surface of the clamping block 1112, a clamping groove 1114 is provided on the inner surface of the switching rod 1113, and a manual lever 1106, a spring 1107, a rotating shaft 1108, a sliding groove 1109, a switching block 1110, a switching shaft 1111, a switching shaft 1111, a clamping block 1112, a switching rod 1113, a switching rod 1113, a switching shaft ... The arrangement of the switching shaft 1111, the block 1112, the switching rod 1113 and the slot 1114, when in use, when it is necessary to switch to manual mode, press the switching rod 1113, let the block 1112 engage in the slot 1114, and then press the switching rod 1113 downward, the downward movement of the switching rod 1113 gives the switching shaft 1111 a power to rotate, so that the switching block 1110 rotates around the switching shaft 1111, thereby giving the switching sleeve 1102 a power to move upward, until the switching sleeve 1102 moves to fit with the manual rod 1106, and the hand wheel 21 is turned, and the hand wheel 21 drives the manual rod 1106 to rotate, because the block 1104 and the manual The rod 1106 fits together, so that the manual rod 1106 drives the switching sleeve 1102 to rotate, the switching sleeve 1102 drives the rotating shaft 1108 to rotate, and the rotating shaft 1108 drives the valve plate 20 to rotate, thereby changing the opening and closing degree of the valve plate 20. When it is necessary to switch to automatic, the switching rod 1113 is rotated to make the block 1112 withdraw from the slot 1114, and the switching block 1110 slides downward until it fits with the worm gear 10, and the motor 6 is started. The motor 6 drives the worm 7 to rotate, thereby driving the worm gear 10 to rotate, and the rotation of the worm gear 10 drives the rotating shaft 1108 to rotate, and the rotating shaft 1108 drives the valve plate 20 to rotate, thereby changing the opening and closing degree of the valve plate 20.

[0023] Furthermore, multiple groups of first connecting blocks 1101 are arranged on the upper surface of the worm gear 10, and multiple groups of connecting grooves 1103 are arranged on the outer surface of the switching sleeve 1102. Through the arrangement of the first connecting blocks 1101 and the connecting grooves 1103, when in use, the first connecting blocks 1101 and the connecting grooves 1103 are engaged, so that the worm gear 10 can drive the rotating shaft 1108 to rotate, and the rotating shaft 1108 drives the valve plate 20 to rotate, thereby changing the opening and closing degree of the valve plate 20.

[0024] Furthermore, two groups of blocks 1104 are provided on the lower surface of the switching sleeve 1102, and multiple groups of sliders 1105 are provided on the inner surface of the switching sleeve 1102. Through the setting of the blocks 1104 and the sliders 1105, when in use, the blocks 1104 and the manual rod 1106 fit together, so that the manual rod 1106 can drive the switching sleeve 1102 to rotate, thereby achieving the purpose of changing the opening and closing degree of the valve plate 20.

[0025] Furthermore, the slide groove 1109 is provided with multiple groups on the outer surface of the slide groove 1109, and the outer wall surface size of the block 1112 is consistent with the inner wall surface size of the slot 1114. Through the setting of the slide groove 1109 and the block 1112, when in use, the slide groove 1109 limits the movement direction of the slider 1105, so that the slider 1105 can only move along the track of the slide groove 1109.

[0026] Furthermore, the connecting piece 3 is provided with multiple groups on one side surface of the indicating chip 2, and the outer wall surface size of the worm 7 is consistent with the inner wall surface size of the worm groove 9. Through the setting of the connecting piece 3 and the worm 7, when in use, the worm wheel 10 rotates to drive the rotating shaft 1108 to rotate, and the rotating shaft 1108 drives the valve plate 20 to rotate, thereby changing the opening and closing degree of the valve plate 20.

[0027] Furthermore, multiple groups of connecting pins 14 are arranged on the inner surface of the upper shaft valve 13, and multiple groups of support frames 17 are arranged on the outer surface of the lower shaft valve 16. Through the arrangement of the connecting pins 14 and the support frames 17, when in use, the support frames 17 allow the lower shaft valve 16 to be more firmly connected to the butterfly valve 18, thereby making the butterfly valve 18 more stable during operation.

[0028] Furthermore, multiple groups of connecting ports 19 are arranged on the outer surface of the butterfly valve 18, and the inner wall surface size of the butterfly valve 18 is consistent with the outer wall surface size of the valve plate 20. Through the arrangement of the connecting ports 19 and the butterfly valve 18, when the butterfly valve 18 is damaged during use, the connecting ports 19 make it possible to quickly replace the butterfly valve 18 without affecting the entire pipeline system.

[0029] Working principle: When it is necessary to switch to manual mode, press and hold the switch rod 1113, let the block 1112 engage in the slot 1114, and then press the switch rod 1113 downward. The downward movement of the switch rod 1113 gives the switch shaft 1111 a rotational force, so that the switch block 1110 rotates around the switch shaft 1111, thereby giving the switch sleeve 1102 an upward movement force until the switch sleeve 1102 moves to fit with the manual rod 1106, and the hand wheel 21 is turned. The hand wheel 21 drives the manual rod 1106 to rotate because the block 1104 and the manual rod 1106 are in contact. The manual lever 1106 drives the switching sleeve 1102 to rotate, the switching sleeve 1102 drives the rotating shaft 1108 to rotate, the rotating shaft 1108 drives the valve plate 20 to rotate, thereby changing the opening and closing degree of the valve plate 20. When it is necessary to switch to automatic, the switching lever 1113 is rotated to make the block 1112 withdraw from the card slot 1114, the switching block 1110 slides downward until it fits with the worm gear 10, the motor 6 is started, the motor 6 drives the worm 7 to rotate, thereby driving the worm gear 10 to rotate, the rotation of the worm gear 10 drives the rotating shaft 1108 to rotate, and the rotating shaft 1108 drives the valve The door plate 20 rotates, thereby changing the opening and closing degree of the valve plate 20. When the rotating shaft 1108 is rotated, 1108 drives the rotating plate 1201 to rotate, and the movable rod 12039 moves toward the center with the rotation of the rotating plate 1201, driving the second connecting block 1204 and the trapezoidal block 1205 to move toward the center together, so as to achieve the purpose of contracting the trapezoidal block 1205, so that the valve plate 20 can be rotated at will. When it is necessary to fix the valve plate 20 at the maximum opening, the rotating shaft 1108 is rotated in the opposite direction, so that the trapezoidal block 1205 moves outward, thereby engaging with the shaft sleeve 1206. In the trapezoidal groove 1207, the valve plate 20 no longer rotates and maintains the maximum opening state, which solves the problem that the existing valve actuator, when in use, the valve plate has no limit protection device and is prone to shifting position during operation, resulting in the valve being unable to accurately reach the preset opening, affecting the flow control accuracy of the system, and may even cause medium leakage or system shutdown, thereby increasing equipment maintenance costs and production safety risks, and resulting in extended operation response time, which reduces production efficiency, further affecting the stability of the overall process flow and product quality.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A limit protection device for a valve actuator, comprising an actuator (1), characterized in that: The inner surface of the actuator (1) is fixedly connected to an indication chip (2), one side surface of the indication chip (2) is fixedly connected to a connecting piece (3), one side surface of the connecting piece (3) is fixedly connected to a control panel (4), the inner surface of the actuator (1) is fixedly connected to a control cabinet (5), the inner surface of the actuator (1) is fixedly connected to a motor (6), one side surface of the motor (6) is fixedly connected to a worm (7), and the outer surface of the actuator (1) is fixedly connected to a valve body ( 8), a worm groove (9) is formed on the outer surface of the valve body (8), a worm wheel (10) is meshed on the outer surface of the worm (7), and a switching mechanism (11) is provided on the upper surface of the worm wheel (10), wherein the switching mechanism (11) comprises a first connecting block (1101), a switching sleeve (1102), a connecting groove (1103), a stopper (1104), a sliding block (1105), a manual lever (1106), a spring (1107), a rotating shaft (1108), a sliding groove (1109), A switching block (1110), a switching shaft (1111), a clamping block (1112), a switching rod (1113) and a clamping groove (1114); a limiting mechanism (12) is provided on the outer surface of the rotating shaft (1108); an upper shaft valve (13) is fixedly connected to the outer surface of the rotating shaft (1108); a connecting pin (14) is slidably connected to the inner surface of the upper shaft valve (13); a locking block (15) is rotatably connected to the outer surface of the connecting pin (14); and the outer surface of the connecting pin (14) is rotatably connected to the locking block (15). A lower shaft valve (16) is slidably connected to the rotating shaft (1108); the outer surface of the lower shaft valve (16) is fixedly connected to a support frame (17); the lower surface of the support frame (17) is fixedly connected to a butterfly valve (18); the outer surface of the butterfly valve (18) is provided with a connection port (19); the lower surface of the rotating shaft (1108) is fixedly connected to a valve plate (20); the upper surface of the rotating shaft (1108) is fixedly connected to a hand wheel (21); and the upper surface of the hand wheel (21) is fixedly connected to a handle (22); The limiting mechanism (12) comprises a rotating plate (1201), a movable opening (1202), a movable rod (1203), a second connecting block (1204), a trapezoidal block (1205), a shaft sleeve (1206) and a trapezoidal groove (1207); the outer surface of the rotating shaft (1108) is fixedly connected to the rotating plate (1201); the outer surface of the rotating plate (1201) is provided with a movable opening (1202); the inner surface of the movable opening (1202) is slidably connected to the movable rod (1203); the outer surface of the movable rod (1203) is fixedly connected to the second connecting block (1204); the upper surface of the second connecting block (1204) is fixedly connected to the trapezoidal block (1205); the outer surface of the rotating shaft (1108) is fixedly connected to the shaft sleeve (1206); and the inner surface of the shaft sleeve (1206) is provided with a trapezoidal groove (1207).

2. A limit protection device for a valve actuator according to claim 1, characterized in that: The movable openings (1202) are arranged in multiple groups on the outer surface of the rotating plate (1201), and the movable openings (1202) are arranged symmetrically with respect to the central axis of the rotating plate (1201).

3. The limit protection device for a valve actuator according to claim 1, characterized in that: The dimensions of the outer wall surface of the trapezoidal block (1205) match the dimensions of the inner wall surface of the trapezoidal groove (1207), and a plurality of groups of the trapezoidal grooves (1207) are provided on the inner surface of the shaft sleeve (1206).

4. The limit protection device for a valve actuator according to claim 1, characterized in that: The upper surface of the upper surface of the worm gear (10) is fixedly connected to a first connecting block (1101); the outer surface of the first connecting block (1101) is slidably connected to a switching sleeve (1102); the outer surface of the switching sleeve (1102) is provided with a connecting groove (1103); the upper surface of the switching sleeve (1102) is fixedly connected to a stopper (1104); the inner surface of the switching sleeve (1102) is fixedly connected to a sliding block (1105); the outer surface of the stopper (1104) is slidably connected to a manual rod (1106); and the lower surface of the manual rod (1106) is fixedly connected to a spring (1106). 107), the inner surface of the switching sleeve (1102) is slidably connected to a rotating shaft (1108), the outer surface of the rotating shaft (1108) is provided with a sliding groove (1109), the lower surface of the switching sleeve (1102) is rotatably connected to a switching block (1110), a side surface of the switching block (1110) is fixedly connected to a switching shaft (1111), the outer surface of the switching shaft (1111) is fixedly connected to a clamping block (1112), the outer surface of the clamping block (1112) is slidably connected to a switching rod (1113), and the inner surface of the switching rod (1113) is provided with a clamping groove (1114).

5. The limit protection device for a valve actuator according to claim 1, characterized in that: The first connection blocks (1101) are provided in multiple groups on the upper surface of the worm wheel (10), and the connection grooves (1103) are provided in multiple groups on the outer surface of the switching sleeve (1102).

6. The limit protection device for a valve actuator according to claim 1, characterized in that: Two groups of the stoppers (1104) are provided on the lower surface of the switching sleeve (1102), and multiple groups of the sliders (1105) are provided on the inner surface of the switching sleeve (1102).

7. The limit protection device for a valve actuator according to claim 1, characterized in that: The slide groove (1109) is provided with a plurality of groups on the outer surface of the slide groove (1109), and the outer wall surface size of the clamping block (1112) matches the inner wall surface size of the clamping groove (1114).

8. The limit protection device for a valve actuator according to claim 1, characterized in that: The connecting pieces (3) are provided in multiple groups on a surface of one side of the indicating chip (2), and the size of the outer wall surface of the worm (7) matches the size of the inner wall surface of the worm groove (9).

9. The limit protection device for a valve actuator according to claim 1, characterized in that: The connecting pins (14) are provided in multiple groups on the inner surface of the upper shaft valve (13), and the supporting frames (17) are provided in multiple groups on the outer surface of the lower shaft valve (16).

10. The limit protection device for a valve actuator according to claim 1, characterized in that: The connection ports (19) are arranged in multiple groups on the outer surface of the butterfly valve (18), and the dimensions of the inner wall surface of the butterfly valve (18) match the dimensions of the outer wall surface of the valve plate (20).

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