Diaphragm type pneumatic actuator for lifting rod ball valve

Abstract

The diaphragm type pneumatic actuator comprises a shell which is formed by detachably connecting an upper cover and a lower cover and provided with a piston cavity, a piston assembly is arranged in the piston cavity of the shell, and the piston assembly comprises a diaphragm, a diaphragm disc and a piston rod; the middle part of the diaphragm is tightly pressed between the two fixedly connected diaphragm discs, and the edge part of the diaphragm is tightly pressed between the upper cover and the lower cover of the shell; the diaphragm divides the piston cavity into an upper cavity and a lower cavity, a first air source connector communicated with the upper cavity of the piston cavity is arranged on the upper cover in a penetrating mode, and a second air source connector communicated with the lower cavity of the piston cavity is arranged on the lower cover in a penetrating mode. The piston rod is fixedly connected with the lower diaphragm disc and extends downwards out of the piston cavity, and the end, extending out of the piston cavity, of the piston rod is a valve rod connecting end; and the manual lifting mechanism is fixedly connected with the upper diaphragm disc. According to the lifting rod ball valve, normal use of the lifting rod ball valve in emergency can be guaranteed through two different operation modes of pneumatic operation and manual operation.

Description

Technical Field

[0001] The utility model relates to the technical field of valve equipment, in particular to a diaphragm type pneumatic actuator for a rising stem ball valve. Background Art

[0002] A rising stem ball valve is a ball valve with a special operation mode. For an ordinary ball valve, the valve ball can be rotated by 90° through driving the valve stem to cut off or connect a fluid pipeline; while the valve stem in a rising stem ball valve performs two actions: up-and-down lifting movement and rotational movement, so that after the valve ball rotates, it adheres to or disengages from the valve seat and then rotates to cut off or connect the fluid pipeline.

[0003] For example, the Chinese invention patent application with the publication number CN116677793A discloses a new type of two-way sealed lifting stem ball valve, and its technical solution includes a valve body, a ball, a valve stem, a valve seat, etc.; the lifting stem ball valve further includes a linkage pressurizing assembly, and the linkage pressurizing assembly includes a pressure diaphragm, an upper pressure plate, a lower pressure plate and a connecting pipeline; the pressure chamber, the first pressure flow channel, the connecting pipeline, the annular flow channel and the second pressure flow channel are sequentially communicated to form a pressure channel to apply a reverse acting force towards the spherical sealing ring to the valve seat. The technical solution of this invention application adds a linkage pressurizing assembly to the overall ball valve. The downward acting force applied by the actuator to the valve stem and the downward acting force applied by the actuator are jointly applied to the linkage pressurizing assembly connected to the valve stem to assist in pressing the valve seat, and together with the medium pressure in the valve body, act on the valve seat, so that it moves slightly to the left and contacts the ball, and can meet the high-quality sealing requirements of both high and low medium pressures.

[0004] Although the technical solution of the above patent discloses lifting the valve stem through a pneumatic actuator, when an emergency occurs and the pneumatic actuator cannot be started, the technical solution of this patent cannot operate the rising stem ball valve manually, so it cannot meet the use requirements of the rising stem ball valve in case of an emergency. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a diaphragm type pneumatic actuator for a rising stem ball valve, which can realize the opening and closing of the valve through two different operation modes: pneumatic and manual.

[0006] The technical solution adopted by the present utility model to solve the above technical problems is as follows: A diaphragm-type pneumatic actuator for a rising stem ball valve, comprising a housing with a piston chamber formed by detachably connecting an upper cover and a lower cover. A piston assembly is provided in the piston chamber of the housing. The piston assembly includes a diaphragm, a diaphragm disc, and a piston rod. The middle part of the diaphragm is pressed between two fixedly connected diaphragm discs, and the edge part of the diaphragm is pressed between the upper cover and the lower cover of the housing. The diaphragm divides the piston chamber into upper and lower chambers. A first air source interface communicating with the upper chamber of the piston chamber is provided through the upper cover, and a second air source interface communicating with the lower chamber of the piston chamber is provided through the lower cover. The piston rod is fixedly connected to the lower diaphragm disc and extends downward out of the piston chamber. One end of the piston rod extending out of the piston chamber is a valve rod connection end. It also includes a manual lifting mechanism fixedly connected to the upper diaphragm disc.

[0007] The manual lifting mechanism includes a lifting rod, a driving screw rod, a nut sleeve, and a handwheel. The lifting rod is fixedly connected to the upper diaphragm disc and extends upward out of the piston chamber. The nut sleeve is vertically fixed on the upper cover, and the driving screw rod is inserted into the nut sleeve and is in threaded cooperation with the nut sleeve. A through hole for clearance fit with the lifting rod is axially provided on the driving screw rod. The lifting rod sequentially passes through the nut sleeve and the driving screw rod upward. Limiting structures for axial limiting cooperation with the driving screw rod are provided on the upper and lower parts of the lifting rod. The handwheel is in transmission cooperation with the driving screw rod, and rotating the handwheel can drive the driving screw rod to rotate.

[0008] As an improvement to the above solution: A base and an internal thread blind hole are provided at the bottom end of the lifting rod. The outer diameter of the piston rod near the top end decreases sequentially to form three stepped stages. An external thread for threaded connection with the internal thread blind hole of the lifting rod is provided on the outermost stepped stage of the piston rod. The middle stepped stage of the piston rod penetrates the diaphragm disc and the diaphragm. The innermost stepped stage of the piston rod cooperates with the base of the lifting rod to clamp the diaphragm and the two diaphragm discs.

[0009] As an improvement to the above solution: A rectangular end is provided at one end of the driving screw rod in cooperation with the handwheel. A matching part is fixedly connected to the handwheel, and a rectangular limiting groove adapted to the rectangular end of the driving screw rod is provided on the matching part.

[0010] As an improvement to the above solution: Thrust ball bearings are installed below the limiting structure on the upper part of the lifting rod and above the limiting structure on the lower part of the lifting rod. The upper thrust ball bearing is fixed at the installation position by an elastic retaining ring, and the lower thrust ball bearing is fixed at the installation position by a nut, a spring washer, and a plain washer.

[0011] As an improvement to the above solution: It further includes an upper dust cover and a lower dust cover fixedly connected to the fitting part of the handwheel. The lower dust cover is fixedly connected to the lower end of the fitting part and sleeved outside the nut sleeve, and the upper dust cover is fixedly connected to the upper end of the fitting part and sleeved outside the rectangular end. One end of the driving lead screw with the rectangular end is fixed with a limiting convex ring that forms an axial limiting fit with the lower dust cover or the fitting part of the handwheel.

[0012] As an improvement to the above solution: The outer peripheral surface of the nut sleeve is provided with a positioning groove, and the positioning groove is an annular groove. A locking screw that forms an insertion fit with the positioning groove is threadedly connected to the lower dust cover, and the positioning groove is an annular groove.

[0013] As an improvement to the above solution: Sealing rings are provided between the diaphragm and the diaphragm disc, between the diaphragm disc and the piston rod, between the piston rod and the lower cover, between the lifting rod and the upper cover, and between the nut sleeve and the lower dust cover.

[0014] As an improvement to the above solution: The diaphragm is made of rubber material, and a mesh cloth is also provided inside the rubber.

[0015] As an improvement to the above solution: It further includes a stroke indicating rod detachably connected to the diaphragm disc located below. A sealing sleeve is threadedly connected to the lower cover, and the stroke indicating rod passes through the sealing sleeve and extends outside the piston chamber.

[0016] As an improvement to the above solution: The valve rod connection end of the piston rod is provided with an internal threaded hole. A guiding key is installed on the outer peripheral surface of the piston rod, and a key groove adapted to the guiding key is provided on the lower cover.

[0017] The beneficial effects of the present utility model are as follows: The present utility model divides the piston chamber of the housing into two chambers through a piston assembly including a diaphragm and a diaphragm disc, and uses the air source to communicate with different chambers for inflation to drive the piston assembly to rise and fall in the piston chamber, thereby driving the piston rod connected to the diaphragm disc to make a lifting movement, realizing the pneumatic control of the valve rod connected to the piston rod. The present utility model is provided with a manual lifting mechanism, and uses the handwheel in the manual lifting mechanism to drive the driving lead screw to rotate, so that a relative lifting occurs between the driving lead screw and the nut sleeve with a threaded fit, and uses the lifting action of the driving lead screw to drive the lifting rod connected to the diaphragm disc to make a lifting movement, realizing the manual control of the valve rod connected to the piston rod. The present utility model meets the operation requirements of the rising stem ball valve under normal working conditions and in case of emergency when pneumatic operation is unavailable through two different operation methods of pneumatic and manual, and can ensure the normal use of the rising stem ball valve in case of emergency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an axonometric view of the diaphragm type pneumatic actuator;

[0019] Figure 2 Cross-sectional view of the diaphragm pneumatic actuator when opening the valve pneumatically;

[0020] Figure 3 Cross-sectional view of the diaphragm pneumatic actuator when closing the valve pneumatically;

[0021] Figure 4 Cross-sectional view of the diaphragm pneumatic actuator when opening the valve manually;

[0022] Figure 5 Cross-sectional view of the diaphragm pneumatic actuator when closing the valve manually;

[0023] Figure 6 Schematic diagram of the un-locked state of the lower dust cover and the nut sleeve;

[0024] Figure 7 Schematic diagram of the locked state of the lower dust cover and the nut sleeve.

[0025] The markings in the figure are: 110 - upper cover, 111 - first air source interface, 120 - lower cover, 121 - second air source interface, 210 - diaphragm, 220 - diaphragm disc, 230 - piston rod, 231 - guide key, 310 - lifting rod, 320 - driving lead screw, 330 - nut sleeve, 340 - hand wheel, 400 - thrust ball bearing, 510 - upper dust cover, 520 - lower dust cover, 610 - positioning groove, 620 - locking screw, 700 - sealing ring, 810 - stroke indicating rod, 820 - sealing sleeve. Specific embodiments

[0026] For the convenience of understanding the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "front", "rear", "left", "right", "upper", "lower", "inner", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0028] Such as Figures 1 to 5As shown in the figure, the diaphragm pneumatic actuator for a rising stem ball valve disclosed by the present utility model includes a housing having a piston chamber. The housing is composed of an upper cover 110 and a lower cover 120 detachably connected by a plurality of bolts. A piston assembly is provided in the piston chamber inside the housing, and a first air source interface 111 penetrating the upper cover 110 is provided on the upper cover 110, and a second air source interface 121 penetrating the lower cover 120 is provided on the lower cover 120. The piston assembly includes a diaphragm 210, a diaphragm disc 220, and a piston rod 230. The diaphragm 210 is made of a flexible and airtight material. Two diaphragm discs 220 clamp the middle part of the diaphragm 210 from the upper and lower sides of the diaphragm 210 respectively. The edge part of the diaphragm 210 extends between the upper cover 110 and the lower cover 120, and the edge part of the diaphragm 210 is clamped by the upper cover 110 and the lower cover 120 to fix the diaphragm 210. There is an unclamped part between the edge part and the middle part of the diaphragm 210, and this part of the diaphragm 210 adapts to the movement of the piston assembly in the piston chamber through deformation. The diaphragm 210 divides the piston chamber in the housing into upper and lower parts, namely an upper chamber communicating with the first air source interface 111 and a lower chamber communicating with the second air source interface 121. Both the first air source interface 111 and the second air source interface 121 are connected to an external air source. The air source can transmit high-pressure gas into different chambers in the piston chamber through the first air source interface 111 and the second air source interface 121, so as to drive the piston assembly to move up and down in the piston chamber by forming a pressure difference between the upper and lower chambers, and make the piston rod 230 connected to the diaphragm disc 220 located below move up and down synchronously.

[0029] In order to ensure the sealing effect of the diaphragm 210 on the piston chamber, the diaphragm 210 is supported by a rubber material, and a mesh cloth can be added inside the rubber to enhance the strength of the diaphragm 210 and improve the service life of the diaphragm 210. The present utility model uses the diaphragm 210 to achieve pneumatic operation. Compared with the conventional linear pneumatic actuator in the prior art, there is no frictional movement between the piston assembly and the inner wall of the housing in the present utility model, and it can provide a thrust not less than that of the linear pneumatic actuator, which can meet the use requirements of the rising stem ball valve. Moreover, since the diaphragm 210 is made of a flexible material and has a light weight, the diaphragm pneumatic actuator of the same size is more portable than the linear pneumatic actuator.

[0030] In order to enable the staff to intuitively understand the opening and closing state of the rising stem ball valve when operating the pneumatic actuator to control the opening and closing of the rising stem ball valve, the present utility model also provides a stroke indicating rod 810, as Figures 2 to 5As shown, the stroke indicator rod 810 is detachably connected to the diaphragm disc 220 located below through screws and elastic pins. A threaded hole is provided on the lower cover 120, and a sealing sleeve 820 is threadedly connected to the threaded hole, so that one end of the stroke indicator rod 810 passes through the sealing sleeve 820 and extends outside the piston chamber. By the length of the stroke indicator rod 810 extending outside the housing, the opening and closing state and the degree of opening and closing of the lift rod ball valve can be intuitively understood at this time.

[0031] One end of the piston rod 230 that is not connected to the diaphragm disc 220 is the valve rod connection end. The valve rod connection end of the piston rod 230 extends outside the piston chamber. If the valve rod of the lift rod ball valve is connected to the valve rod connection end of the piston rod 230, the valve rod of the lift rod ball valve can be driven to move up and down by driving the piston assembly through the air source; at the same time, in the present utility model, a threaded connection is adopted as the connection method between the piston rod 230 and the valve rod, so the connection between the valve rod and the piston rod 230 will not affect the rotation of the valve rod, and the valve rod can take into account two movement modes of lifting and rotation, meeting the opening and closing operations of the lift rod ball valve.

[0032] Further, in order to ensure that the piston rod 230 will not be affected by the torque during the rotation of the valve rod and make the piston rod 230 only move up and down, as Figures 2 to 5 shown, the present utility model also installs a guide key 231 on the outer peripheral surface of the piston rod 230. At the same time, a keyway adapted to the guide key 231 is provided at the corresponding position of the lower cover 120. The keyway extends vertically along the lifting direction of the piston rod 230, so that the guide key 231 can move up and down along the keyway, and the movement of the piston rod 230 is guided through the cooperation of the keyway and the guide key 231.

[0033] The above structure can realize the opening and closing operation of the lift rod ball valve in a pneumatic manner. In order to cope with the emergency situation where the lift rod ball valve encounters a failure of the air source or power supply, the present utility model also adds a manual lifting mechanism to the pneumatic actuator, so that the pneumatic actuator can also open and close the lift rod ball valve by manual operation; a manual lifting mechanism is fixedly connected to the diaphragm disc 220 located above, and the entire piston assembly is driven to lift through the manual lifting mechanism.

[0034] Specifically, as Figures 2 to 5As shown in the figure, the manual lifting mechanism adopted in the utility model includes a lifting rod 310, a driving lead screw 320, a nut sleeve 330 and a hand wheel 340. The lifting rod 310 is fixedly connected to the diaphragm disc 220 located above and extends upward out of the piston chamber. The lifting and lowering movement of the lifting rod 310 can drive the entire piston assembly to perform lifting and lowering movements. The nut sleeve 330 is a cylindrical structure with a through hole. The through hole of the nut sleeve 330 is an internal thread through hole. The nut sleeve 330 is vertically arranged and fixedly connected to the upper cover 110. An external thread adapted to the internal thread hole of the nut sleeve 330 is provided on the outer peripheral surface of the driving lead screw 320. The driving lead screw 320 also has a through hole axially arranged. The driving lead screw 320 is inserted into the nut sleeve 330 and is in threaded cooperation with the nut sleeve 330. The lifting rod 310 forms a clearance fit with the through hole of the driving lead screw 320. The lifting rod 310 sequentially passes through the nut sleeve 330 and the driving lead screw 320 upward. Limiting structures are provided at both the upper and lower parts of the lifting rod 310. The limiting structure located at the upper part of the lifting rod 310 forms an axial limiting cooperation with the top end of the driving lead screw 320, and the limiting structure located at the lower part of the lifting rod 310 forms an axial limiting cooperation with the bottom end of the driving lead screw 320. The hand wheel 340 forms a transmission cooperation with the driving lead screw 320. By rotating the hand wheel 340, the driving lead screw 320 can be driven to rotate. When the hand wheel 340 is rotated to drive the driving lead screw 320 to rotate, relative movement occurs between the driving lead screw 320 and the nut sleeve 330. Since the nut sleeve 330 is fixed to the housing, only the driving lead screw 320 can perform lifting and lowering movements. When the driving lead screw 320 contacts the limiting structure on the lifting rod 310 during the lifting and lowering process, it will push the limiting structure of the lifting rod 310, so that the lifting rod 310 performs lifting and lowering movements, and finally drives the entire piston assembly to perform lifting and lowering movements in the piston chamber, so that the piston rod 230 connected to the diaphragm disc 220 located below moves up and down synchronously, realizing the manual opening and closing operation of the lift rod ball valve.

[0035] Furthermore, in order to simplify the structure of the piston assembly and reduce the assembly difficulty of the piston assembly, as Figures 2 to 5 shown, the utility model sets a base and an internal thread blind hole at the bottom end of the lifting rod 310. At the same time, the outer diameter of the piston rod 230 near the top end is sequentially reduced to form three-stage steps. External threads for threaded connection with the internal thread blind hole of the lifting rod 310 are provided on the outermost stage step of the piston rod 230. The middle stage step of the piston rod 230 penetrates the diaphragm disc 220 and the diaphragm 210. The innermost stage step of the piston rod 230 cooperates with the base of the lifting rod 310 to clamp the diaphragm 210 and the two diaphragm discs 220. When the piston rod 230 is threadedly connected to the lifting rod 310, the two diaphragm discs 220 and the diaphragm 210 can be clamped together through the stage steps on the piston rod 230, realizing the fixation of the piston assembly without the need to additionally set other fastening structures, which is beneficial to reducing the production cost and assembly difficulty.

[0036] In the present utility model, the transmission cooperation between the handwheel 340 and the driving lead screw 320 is achieved by means of a limiting structure. In the present utility model, the end of the driving lead screw 320 that is matched with the handwheel 340 is set as a rectangular end, and at the same time, a matching part is fixedly connected to the handwheel 340. The structure of the matching part is not limited. Necessarily, a rectangular limiting groove adapted to the rectangular end of the driving lead screw 320 is provided in the matching part. Inserting the rectangular end of the driving lead screw 320 into the rectangular limiting groove of the matching part of the handwheel 340 can form a circumferential limiting cooperation between the handwheel 340 and the driving lead screw 320, and relative rotation between the handwheel 340 and the driving lead screw 320 will not occur, that is, rotating the handwheel 340 can drive the driving lead screw 320 to rotate synchronously.

[0037] Furthermore, as Figures 2 to 5 shown, two thrust ball bearings 400 are installed on the lifting rod 310 of the present utility model. The installation positions of the thrust ball bearings 400 are below the limiting structure at the upper part of the lifting rod 310 and above the limiting structure at the lower part of the lifting rod 320; the thrust ball bearings 400 are used to bear the thrust load applied by the driving lead screw 320 to the lifting rod 310. The upper thrust ball bearing 400 is fixed at the installation position by an elastic retaining ring, and the lower thrust ball bearing 400 is fixed at the installation position by a nut, a spring washer and a flat washer.

[0038] In order to protect and dust-proof the manual lifting mechanism, the present utility model also provides an upper dust cover 510 and a lower dust cover 520. As Figures 1 to 5 shown, the upper dust cover 510 is fixedly connected to the upper end of the matching part of the handwheel 340 and sleeved outside the rectangular end, and the lower dust cover 520 is fixedly connected to the lower end of the matching part of the handwheel 340 and sleeved outside the nut sleeve 330; and, a limiting convex ring that forms an axial limiting cooperation with the lower dust cover 520 or the matching part of the handwheel 340 is fixed at one end of the driving lead screw 320 provided with the rectangular end. The lifting movement of the driving lead screw 320 is limited by the limiting convex ring to prevent the driving lead screw 320 from disengaging from the nut sleeve 330.

[0039] Furthermore, after the dust cover is provided, the present utility model also provides a positioning groove 610 on the outer peripheral surface of the nut sleeve 330, and at the same time, a locking screw 620 that forms an insertion fit with the positioning groove 610 is threadedly connected to the lower dust cover 520; the positioning groove 610 is an annular groove, so that as long as the positioning groove 610 and the locking screw 620 are at the same height position, the insertion fit can be achieved. As Figure 6As shown, when turning the handwheel 340, the locking screw 620 can be loosened so that the locking screw 620 exits from the positioning groove 610. At this time, the lower dust cover 520 and the nut sleeve 330 can move relative to each other, and then the handwheel 340 can be turned to open and close the lift rod ball valve; such as Figure 7 As shown, after the opening and closing operation of the lift rod ball valve is completed, the locking screw 620 can be tightened so that the locking screw 620 is inserted into the positioning groove 610. At this time, the lower dust cover 520 and the nut sleeve 330 are relatively fixed, and the handwheel 340 is also locked and cannot be turned. Since the manual operation mode is only applicable to opening and closing the lift rod ball valve in case of emergency, after the emergency is over, the manual lifting mechanism must be reset, otherwise the pneumatic actuator cannot work properly when the air source or power supply is normal. After opening the lift rod ball valve in an emergency, the handwheel 340 needs to be rotated clockwise to reset the handwheel 340, and the locking screw 620 is screwed into the positioning groove 610 to lock the handwheel 340; after closing the lift rod ball valve in an emergency, the handwheel 340 needs to be rotated counterclockwise to reset the handwheel 340, and the locking screw 620 is screwed into the positioning groove 610 to lock the handwheel 340.

[0040] To ensure the sealing effect of the present invention, sealing rings 700 are provided at the mating parts where gas leakage may occur in each component of the present invention. The installation positions of the sealing rings 700 include the mating part between the diaphragm 210 and the diaphragm disc 220, the mating part between the diaphragm disc 220 and the piston rod 230, the mating part between the piston rod 230 and the lower cover 120, the mating part between the lift rod 310 and the upper cover 110, and the mating part between the nut sleeve 330 and the lower dust cover 520.

[0041] When opening the lift rod ball valve by pneumatic operation mode, such as Figure 2 As shown, the air source is used to ventilate the second air source interface 121. Due to the partition and sealing effect of the diaphragm 210, the air pressure in the lower chamber of the piston chamber increases. The piston assembly moves upward under the action of air pressure, driving the valve stem connected to the piston rod 230 to lift together, realizing the valve opening action, and at the same time the stroke indicating rod 810 rises synchronously.

[0042] When closing the lift rod ball valve by pneumatic operation mode, such as Figure 3 As shown, the air source is used to ventilate the first air source interface 111. Due to the partition and sealing effect of the diaphragm 210, the air pressure in the upper chamber of the piston chamber increases. The piston assembly moves downward under the action of air pressure, driving the valve stem connected to the piston rod 230 to press down together, realizing the valve closing action, and at the same time the stroke indicating rod 810 descends synchronously.

[0043] When opening the lift rod ball valve by manual operation mode, such as Figure 4As shown in the figure, turn the handwheel 340 counterclockwise to drive the driving lead screw 320 to rotate. The driving lead screw 320 moves upward under the action of the thread engagement structure with the nut sleeve 330. After rising a certain idle stroke, it abuts against the thrust ball bearing 400 located above on the lifting rod 310, thereby pushing the lifting rod 310 upward, driving the piston assembly and the valve stem connected to the piston rod 230 to lift together, realizing the valve opening action, and at the same time, the stroke indicating rod 810 rises synchronously.

[0044] When closing the lift rod ball valve manually, as Figure 5 shown in the figure, turn the handwheel 340 clockwise to drive the driving lead screw 320 to rotate. The driving lead screw 320 moves downward under the action of the thread engagement structure with the nut sleeve 330. After descending a certain idle stroke, it abuts against the thrust ball bearing 400 located below on the lifting rod 310, thereby pushing the lifting rod 310 downward, driving the piston assembly and the valve stem connected to the piston rod 230 to press down together, realizing the valve closing action, and at the same time, the stroke indicating rod 810 descends synchronously.

Claims

1. Diaphragm pneumatic actuator for rising stem ball valve, comprising a housing with a piston chamber formed by detachably connecting an upper cover (110) and a lower cover (120), wherein a piston assembly is provided in the piston chamber of the housing, characterized in that: The piston assembly includes a diaphragm (210), a diaphragm disc (220), and a piston rod (230); the middle part of the diaphragm (210) is pressed between two fixedly connected diaphragm discs (220), and the edge part of the diaphragm (210) is pressed between the upper cover (110) and the lower cover (120) of the housing; the diaphragm (210) divides the piston chamber into upper and lower chambers, a first gas source interface (111) communicating with the upper chamber of the piston chamber is provided through the upper cover (110), and a second gas source interface (121) communicating with the lower chamber of the piston chamber is provided through the lower cover (120); the piston rod (230) is fixedly connected to the lower diaphragm disc (220) and extends downward out of the piston chamber, and one end of the piston rod (230) extending out of the piston chamber is a valve rod connection end; a manual lifting mechanism fixedly connected to the upper diaphragm disc (220) is further included. The manual lifting mechanism includes a lifting rod (310), a driving lead screw (320), a nut sleeve (330), and a handwheel (340); the lifting rod (310) is fixedly connected to the upper diaphragm disc (220) and extends upward out of the piston chamber; the nut sleeve (330) is vertically fixed on the upper cover (110), and the driving lead screw (320) is inserted into the nut sleeve (330) and is in threaded cooperation with the nut sleeve (330); a through hole for clearance fit with the lifting rod (310) is axially provided on the driving lead screw (320), the lifting rod (310) sequentially passes upward through the nut sleeve (330) and the driving lead screw (320), and limiting structures for axially limiting fit with the driving lead screw (320) are provided on both the upper and lower parts of the lifting rod (310); the handwheel (340) is in transmission cooperation with the driving lead screw (320), and rotating the handwheel (340) can drive the driving lead screw (320) to rotate.

2. The diaphragm pneumatic actuator for a rising stem ball valve according to claim 1, wherein: A base and an internal thread blind hole are provided at the bottom end of the lifting rod (310), the outer diameter of the piston rod (230) near the top end decreases sequentially to form three stepped stages, an external thread for threaded connection with the internal thread blind hole of the lifting rod (310) is provided on the outermost stepped stage of the piston rod (230), the middle stepped stage of the piston rod (230) penetrates the diaphragm disc (220) and the diaphragm (210), and the innermost stepped stage of the piston rod (230) cooperates with the base of the lifting rod (310) to clamp the diaphragm (210) and the two diaphragm discs (220).

3. The diaphragm pneumatic actuator for the rising stem ball valve according to claim 1, characterized in that: Thrust ball bearings (400) are installed both below the limiting structure on the upper part of the lifting rod (310) and above the limiting structure on the lower part of the lifting rod (310); the upper thrust ball bearing (400) is fixed at the installation position by an elastic retaining ring, and the lower thrust ball bearing (400) is fixed at the installation position by a nut, a spring washer, and a plain washer.

4. The diaphragm pneumatic actuator for the rising stem ball valve according to claim 1, characterized in that: One end of the driving lead screw (320) cooperating with the handwheel (340) is provided with a rectangular end, a cooperating part is fixedly connected to the handwheel (340), and the cooperating part is provided with a rectangular limiting groove adapted to the rectangular end of the driving lead screw (320).

5. The diaphragm pneumatic actuator for a rising stem ball valve according to claim 4, characterized in that: It further includes an upper dust cover (510) and a lower dust cover (520) fixedly connected to the mating portion of the handwheel (340). The lower dust cover (520) is fixedly connected to the lower end of the mating portion and sleeved outside the nut sleeve (330), and the upper dust cover (510) is fixedly connected to the upper end of the mating portion and sleeved outside the rectangular end; one end of the driving lead screw (320) provided with a rectangular end is fixed with a limiting convex ring that forms an axial limiting fit with the mating portion of the lower dust cover (520) or the handwheel (340).

6. The diaphragm pneumatic actuator for a rising stem ball valve according to claim 5, characterized in that: A positioning groove (610) is provided on the outer peripheral surface of the nut sleeve (330), and the positioning groove (610) is an annular groove; a locking screw (620) that forms an insertion fit with the positioning groove (610) is threadedly connected to the lower dust cover (520).

7. The diaphragm pneumatic actuator for a rising stem ball valve as claimed in claim 5, wherein: Sealing rings (700) are provided between the diaphragm (210) and the diaphragm disc (220), between the diaphragm disc (220) and the piston rod (230), between the piston rod (230) and the lower cover (120), between the lifting rod (310) and the upper cover (110), and between the nut sleeve (330) and the lower dust cover (520).

8. The diaphragm pneumatic actuator for the rising stem ball valve according to claim 1, characterized in that: The diaphragm (210) is made of rubber, and a mesh cloth is further provided inside the rubber.

9. The diaphragm pneumatic actuator for the rising stem ball valve according to claim 1, characterized in that: It further includes a stroke indicating rod (810) detachably connected to the diaphragm disc (220) located below. A sealing sleeve (820) is threadedly connected to the lower cover (120), and the stroke indicating rod (810) passes through the sealing sleeve (820) and extends outside the piston chamber.

10. The diaphragm pneumatic actuator for the rising stem ball valve according to claim 1, characterized in that: The valve rod connection end of the piston rod (230) is provided with an internal threaded hole. A guiding key (231) is installed on the outer peripheral surface of the piston rod (230), and a key groove adapted to the guiding key (231) is provided on the lower cover (120).

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