Straight stroke pneumatic actuator for lifting rod ball valve

Abstract

The utility model discloses a straight stroke pneumatic actuator for a lifting rod ball valve. A piston cavity is divided into an upper cavity and a lower cavity by a partition plate; a first upper cavity air source connector is formed in the upper cover in a penetrating mode, a first lower cavity air source connector is formed in the lower cover in a penetrating mode, and a second upper cavity air source connector and a second lower cavity air source connector are formed in the partition plate; the piston assembly comprises a piston rod, an upper piston disc and a lower piston disc, the upper piston disc and the lower piston disc are fixed to the piston rod, the upper piston disc is located in an upper cavity of the piston cavity and matched with the upper cavity in a sealed mode, the lower piston disc is located in a lower cavity of the piston cavity and matched with the lower cavity in a sealed mode, and the piston rod penetrates through the partition plate and the lower end of the piston rod extends out of the piston cavity. One end of the piston rod extending out of the piston cavity is a valve rod connecting end; the manual lifting mechanism is detachably connected with the upper end of the piston rod. 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 linear pneumatic actuator for a rising stem ball valve. Background Technique

[0002] A rising stem ball valve is a ball valve with a special operation mode. An ordinary ball valve can cut off or connect a fluid pipeline only by driving the valve stem to rotate the valve ball by 90°; while the valve stem in the 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 utility model patent document with the publication number CN212004501U discloses a large-thrust pneumatic actuator for a plunger valve and a rising stem ball valve, which includes an upper cylinder head, an intermediate seat, a lower cylinder head and a piston rod. An upper cylinder body is fixed between the upper cylinder head and the intermediate seat, and a lower cylinder body is fixed between the lower cylinder head and the intermediate seat; the piston rod passes through the lower cylinder head and the upper cylinder head from bottom to top; an upper piston is fixed on the piston rod between the upper cylinder head and the intermediate seat, and the outer circumference of the upper piston is in contact and cooperation with the inner surface of the upper cylinder body; a lower piston is fixed on the piston rod between the lower cylinder head and the intermediate seat, and the outer circumference of the lower piston is in contact and cooperation with the inner surface of the lower cylinder body; a sleeve is sleeved on the piston rod, the lower end surface of the sleeve is in contact and cooperation with the upper end surface of the lower piston, and the upper end surface of the sleeve is in contact and cooperation with the lower end surface of the upper piston; an anti-rotation key is arranged below the piston rod and the lower cylinder head, and the anti-rotation key is in keyway fit.

[0004] Although the technical solution of the above patent discloses enhancing the thrust of the pneumatic actuator on the valve stem by setting a double-cylinder air cylinder, when the pneumatic actuator cannot be started in an emergency, 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 emergency. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a linear 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 linear 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. It further includes a partition fixed in the housing, and the partition divides the piston chamber into upper and lower chambers; a first upper chamber air source interface communicating with the upper chamber is provided through the upper cover, a first lower chamber air source interface communicating with the lower chamber is provided through the lower cover, a second upper chamber air source interface communicating from outside the housing to the upper chamber and a second lower chamber air source interface communicating from outside the housing to the lower chamber are provided on the partition; the piston assembly includes a piston rod, an upper piston disc and a lower piston disc fixed on the piston rod. The upper piston disc is located in the upper chamber of the piston chamber and is in sealing cooperation with the upper chamber, the lower piston disc is located in the lower chamber of the piston chamber and is in sealing cooperation with the lower chamber. The piston rod penetrates through the partition and the lower end of the piston rod extends outside the piston chamber, and one end of the piston rod extending outside the piston chamber is a valve rod connection end; it further includes a manual lifting mechanism detachably connected to the upper end of the piston rod.

[0007] The manual lifting mechanism includes a lifting rod, a driving lead screw, a nut sleeve and a handwheel; the lifting rod is detachably connected to the upper end of the piston rod and extends upward outside the piston chamber, and a through hole for the lifting rod to pass through is provided on the upper cover; the nut sleeve is vertically fixed on the upper cover and seals the through hole of the upper cover, the driving lead screw is inserted into the nut sleeve and is in threaded cooperation with the nut sleeve; a through hole in clearance fit with the lifting rod is axially provided on the driving lead screw, the lifting rod passes through the nut sleeve and the driving lead screw upward in sequence, and limiting structures for axially limiting cooperation with the driving lead screw are provided on both the upper and lower parts of the lifting rod; the handwheel is in transmission cooperation with the driving lead screw, and rotating the handwheel can drive the driving lead screw to rotate.

[0008] 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 thrust ball bearing located above is fixed at the installation position by an elastic retaining ring, and the thrust ball bearing located below is fixed at the installation position by a nut, a spring washer and a plain washer.

[0009] As an improvement to the above solution: The end of the driving lead screw cooperating with the handwheel is provided with a rectangular end, and a cooperating part is fixedly connected to the handwheel, and the cooperating part is provided with a rectangular limiting groove adapted to the rectangular end of the driving lead screw.

[0010] As an improvement to the above solution: It further includes an upper dust cover and a lower dust cover fixedly connected to the cooperating part of the handwheel. The lower dust cover is fixedly connected to the lower end of the cooperating part and sleeved outside the nut sleeve, and the upper dust cover is fixedly connected to the upper end of the cooperating part and sleeved outside the rectangular end; a limiting convex ring for axially limiting cooperation with the lower dust cover or the cooperating part of the handwheel is fixed at the end of the driving lead screw provided with the rectangular end.

[0011] As an improvement to the above solution: a positioning groove is provided on the outer peripheral surface of the nut sleeve, and the positioning groove is an annular groove; a locking screw that forms a plug-in fit with the positioning groove is threadedly connected to the lower dust cover.

[0012] As an improvement to the above solution: sealing rings are provided between the upper piston disc and the inner wall of the upper chamber, between the lower piston disc and the inner wall of the lower chamber, between the piston rod and the partition plate, between the piston rod and the lower cover, between the nut sleeve and the upper cover, and between the nut sleeve and the lower dust cover.

[0013] As an improvement to the above solution: the sealing rings between the upper piston disc and the inner wall of the upper chamber and between the lower piston disc and the inner wall of the lower chamber are both T-shaped sealing rings; the cross-section of the T-shaped sealing ring is T-shaped, and the T-shaped sealing ring is composed of a bottom ring and an outer ring connected to the middle of the outer side of the bottom ring, and the end face of the outer ring is a circular surface; sealing grooves that form a fitting with the bottom ring are provided on the upper piston disc and the lower piston disc, and retaining rings filled above and below the outer ring are also provided in the sealing grooves.

[0014] As an improvement to the above solution: it further includes a stroke indicating rod detachably connected to the lower piston disc, a sealing sleeve is threadedly connected to the lower cover, and the stroke indicating rod passes through the sealing sleeve and extends out of the piston chamber.

[0015] As an improvement to the above solution: an internal threaded hole is provided at the valve stem connection end of the piston rod, a guide key is installed on the outer peripheral surface of the piston rod, and a key groove adapted to the guide key is provided on the lower cover.

[0016] 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 by providing a partition plate, and further divides the two chambers by the upper piston disc and the lower piston disc in the piston assembly, so as to form a double-layer cylinder in the piston chamber. The piston assembly is pushed to rise and fall in the piston chamber by inflating with the air source communicated with different chambers, thereby driving the piston rod to do lifting motion, and realizing the pneumatic control of the valve stem connected to the piston rod; the present utility model provides double thrust through the double-layer cylinder, making the pneumatic control of the valve stem easier, and the present utility model can effectively reduce the volume of the cylinder compared with a single-cylinder cylinder providing the same thrust; the present utility model is provided with a manual lifting mechanism, and the handwheel in the manual lifting mechanism is used to drive the driving screw to rotate, so that relative lifting occurs between the driving screw and the nut sleeve in threaded fit, and the lifting action of the driving screw is used to push the lifting rod connected to the piston rod to do lifting motion, realizing the manual control of the valve stem 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

[0017] Figure 1 Is an axonometric view of a linear pneumatic actuator;

[0018] Figure 2 Is a cross-sectional view of the linear pneumatic actuator when opening the valve pneumatically;

[0019] Figure 3 Is a cross-sectional view of the linear pneumatic actuator when closing the valve pneumatically;

[0020] Figure 4 Is a cross-sectional view of the linear pneumatic actuator when opening the valve manually;

[0021] Figure 5 Is a cross-sectional view of the linear pneumatic actuator when closing the valve manually;

[0022] Figure 6 Is a schematic diagram of the state where the lower dust cover and the nut sleeve are not locked;

[0023] Figure 7 Is a schematic diagram of the state where the lower dust cover and the nut sleeve are locked;

[0024] Figure 8 Is a schematic assembly structure diagram of the piston disc and the T-shaped sealing ring.

[0025] The marks in the figure are: 110 - upper cover, 111 - first upper chamber air source interface, 120 - lower cover, 121 - second lower chamber air source interface, 130 - partition, 131 - second upper chamber air source interface, 132 - second lower chamber air source interface, 210 - upper piston disc, 220 - lower piston disc, 230 - piston rod, 231 - guiding 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 - T-shaped sealing ring, 710 - bottom ring, 720 - outer ring, 730 - retaining ring, 810 - stroke indicating rod, 820 - sealing sleeve, 900 - end cover. Detailed Description of the Preferred 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 utility model, 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. It is only for convenience of description and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0028] As Figures 1 to 5 shown, the linear pneumatic actuator for a rising stem ball valve disclosed in 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 and a partition 130 are arranged in the piston chamber inside the housing. The partition 130 is transversely arranged in the piston chamber and fixedly connected to the housing. The partition 130 divides the piston chamber into upper and lower chambers, and the upper chamber and the lower chamber are independent of each other. The piston assembly adopted in the present utility model includes an upper piston disc 210, a lower piston disc 220 and a piston rod 230. The upper piston disc 210 and the lower piston disc 220 are both fixed on the piston rod 230. The upper piston disc 210 is located in the upper chamber of the piston chamber, and the lower piston disc 220 is located in the lower chamber of the piston chamber. The upper piston disc 210 is in sealing cooperation with the upper chamber of the piston chamber to form a cylinder, and the lower piston disc 220 is in sealing cooperation with the lower chamber of the piston chamber to form a cylinder, so that a double-cylinder structure is formed in the piston chamber. At the same time, four air inlets are provided in the present utility model, namely a first upper chamber air source interface 111 penetrating through the upper cover 110 and communicating with the upper chamber, a first lower chamber air source interface 121 penetrating through the lower cover 120 and communicating with the lower chamber, a second upper chamber air source interface 131 provided on the partition 130 and communicating from outside the housing to the upper chamber, and a second lower chamber air source interface 132 communicating from outside the housing to the lower chamber. Connecting the above air source interfaces to an external air source can introduce high-pressure gas into different chambers of the double-cylinder structure. Since the upper piston disc 210 and the lower piston disc 220 are both fixed on the piston rod 230, the upper piston disc 210 and the lower piston disc 220 move synchronously. By introducing high-pressure gas through the air source, a pressure difference is formed in the chambers of the upper and lower cylinders to drive the piston assembly to move up and down in the piston chamber, so that the piston rod 230 moves up and down synchronously. Since a double-cylinder structure is adopted in the present utility model, double thrust can be provided by synchronously pushing the upper piston disc 210 and the lower piston disc 220, thereby providing a stronger driving force for the lifting action of the piston rod 230. In addition, compared with a single-cylinder cylinder that can provide the same thrust, the present utility model can reduce the volume of the overall structure and is suitable for an installation environment where the installation space in the horizontal direction is compact and the installation space in the vertical direction is sufficient.

[0029] In order to enable the staff to intuitively understand the opening and closing state of the lift stem ball valve when operating the direct stroke pneumatic actuator to control the opening and closing of the lift stem ball valve, the present utility model also provides a stroke indicating rod 810. As Figures 2 to 5 shown, the stroke indicating rod 810 is detachably connected to the lower piston disc 220 through screws and elastic pins, and threaded holes are provided on the lower cover 120. A sealing sleeve 820 is threadedly connected to the threaded holes, so that one end of the stroke indicating rod 810 passes through the sealing sleeve 820 and extends outside the piston chamber. Through the length of the stroke indicating rod 810 extending outside the housing, the opening and closing state and the degree of opening and closing of the lift stem ball valve at this time can be intuitively understood.

[0030] One end of the piston rod 230 that is not connected to the piston disc is the valve rod connection end. The valve rod connection end of the piston rod 230 extends outside the piston chamber. Connecting the valve rod of the lift stem ball valve to the valve rod connection end of the piston rod 230, the valve rod of the lift stem 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, 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 both the up and down movement and the rotation movement, meeting the opening and closing operations of the lift stem ball valve.

[0031] Further, in order to ensure that the piston rod 230 will not be affected by the torque when the valve rod rotates, so that the piston rod 230 can 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, and at the corresponding position of the lower cover 120, a key groove adapted to the guide key 231 is provided. The key groove extends vertically along the lifting direction of the piston rod 230, so that the guide key 231 can move up and down along the key groove, and the movement of the piston rod 230 is guided through the cooperation of the key groove and the guide key 231.

[0032] The above structure can realize the opening and closing operation of the lift stem ball valve through a pneumatic method. In order to cope with the emergency situation where the lift stem ball valve encounters a failure of the air source or power supply, the present utility model also adds a manual lifting mechanism to the direct stroke pneumatic actuator, so that the direct stroke pneumatic actuator can also perform the opening and closing operation of the lift stem ball valve through manual operation. A manual lifting mechanism is connected to the upper end of the piston rod 230, and the entire piston assembly is driven to lift through the manual lifting mechanism. Since the connection part of the manual lifting mechanism needs to be extended into the piston chamber from outside the piston chamber to be connected to the piston rod 230 when manually lifting the piston rod 230 by using the manual lifting mechanism, a through hole for connection needs to be provided on the upper cover 110 of the housing, and the airtightness of the piston chamber needs to be ensured during pneumatic operation. As Figure 2 and Figure 3As shown in the figure, a end cover 900 is provided on the upper cover 110 corresponding to the present utility model. The end cover 900 is installed on the upper cover 110 by a plurality of bolts in a detachable connection manner. When performing pneumatic operation, the through holes on the upper cover 110 are blocked and sealed by the end cover 900. When performing manual operation, the end cover 900 is detached from the upper cover 110, and the manual lifting mechanism is connected to the piston rod 230.

[0033] Specifically, as Figures 2 to 5 shown in the figure, the manual lifting mechanism adopted in the present 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 detachably connected to the top end of the piston rod 230 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 movement. 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. The outer peripheral surface of the driving lead screw 320 is provided with an external thread adapted to the internal thread hole of the nut sleeve 330, and 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 on both the upper and lower parts of the lifting rod 310. The limiting structure located on 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 on 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 rotating the hand wheel 340 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 on the housing, only the driving lead screw 320 can perform lifting and lowering movement. 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 movement, and finally drives the entire piston assembly to perform lifting and lowering movement in the piston chamber, and the valve rod connected to the lower end of the piston rod 230 is lifted and lowered synchronously, realizing the manual opening and closing operation of the lift rod ball valve.

[0034] Furthermore, as Figures 2 to 5As shown in the figure, two thrust ball bearings 400 are installed on the lifting rod 310. 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 exerted by the driving lead screw 320 on 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.

[0035] In the present utility model, the transmission cooperation between the handwheel 340 and the driving lead screw 320 is realized by means of a limiting structure. One end of the driving lead screw 320 that is matched with the handwheel 340 is set as a rectangular end. At the same time, a matching part is fixedly connected to the handwheel 340. The structure of the matching part is not limited. It is necessary to set a rectangular limiting groove on the matching part that is adapted to the rectangular end of the driving lead screw 320. Insert the rectangular end of the driving lead screw 320 into the rectangular limiting groove of the matching part of the handwheel 340, then a circumferential limiting cooperation can be formed between the handwheel 340 and the driving lead screw 320, and there will be no relative rotation between the handwheel 340 and the driving lead screw 320, that is, rotating the handwheel 340 can drive the driving lead screw 320 to rotate synchronously.

[0036] In order to protect and dust-proof the manual lifting mechanism, the present utility model also provides an upper dust-proof cover 510 and a lower dust-proof cover 520. As Figures 1 to 5 shown, the upper dust-proof cover 510 is fixedly connected to the upper end of the matching part of the handwheel 340 and sleeved outside the rectangular end. The lower dust-proof 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-proof cover 520 or the matching part of the handwheel 340 is fixed at one end of the driving lead screw 320 where the rectangular end is provided. 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.

[0037] Furthermore, after the dust-proof cover is provided, the present utility model also provides a positioning groove 610 on the outer peripheral surface of the nut sleeve 330. At the same time, a locking screw 620 that forms an insertion cooperation with the positioning groove 610 is threadedly connected to the lower dust-proof cover 520. The positioning groove 610 is an annular groove, so that the insertion cooperation can be realized as long as the positioning groove 610 and the locking screw 620 are at the same height position. As Figure 6 shown, when rotating the handwheel 340, the locking screw 620 can be loosened to withdraw the locking screw 620 from the positioning groove 610. At this time, the lower dust-proof cover 520 and the nut sleeve 330 can move relative to each other, and then the handwheel 340 can be rotated to open and close the lift rod ball valve. As Figure 7As shown, after the opening and closing operation of the rising stem 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 rotate. Since the manual operation mode is only applicable to opening and closing the rising stem 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 rising stem 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 rising stem 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.

[0038] To ensure the sealing effect of the present utility model, sealing rings are provided at the mating parts where gas leakage may occur in each component of the present utility model. The setting positions of the sealing rings include the mating part between the upper piston disc 210 and the inner wall of the upper chamber, the mating part between the lower piston disc 220 and the inner wall of the lower chamber, the mating part between the piston rod 230 and the partition plate 130, the mating part between the piston rod 230 and the lower cover 120, the mating part between the nut sleeve 330 and the upper cover 110, and the mating part between the nut sleeve 330 and the lower dust cover 520.

[0039] Furthermore, since the mating part between the piston disc and the piston chamber is the main sealing part of the linear pneumatic actuator, if the seal fails at this place, it will directly cause the actuator to be unable to drive the rising stem ball valve to open and close. If a conventional O-ring is used, it needs to be extruded against the inner wall of the piston chamber to form a sealing fit, and this extrusion force will generate friction, resulting in torque when the O-ring moves up and down with the piston disc, which will reduce the service life of the O-ring. Considering the above problems, as Figures 2 to 5 shown, the present utility model sets the sealing rings between the upper piston disc 210 and the inner wall of the upper chamber and between the lower piston disc 220 and the inner wall of the lower chamber as special T-shaped sealing rings 700. As Figure 8As shown, the cross-section of the T-shaped sealing ring 700 is T-shaped. The T-shaped sealing ring 700 is composed of a bottom ring 710 and an outer ring 720 connected to the middle of the outer side of the bottom ring 710. The end face of the outer ring 720 is a circular surface. Sealing grooves that form a fitting cooperation with the bottom ring 710 are provided on the upper piston disk 210 and the lower piston disk 220, and retaining rings 730 filled above and below the outer ring 720 are also arranged in the sealing grooves. By adopting the special T-shaped sealing ring 700, the bottom ring 710 of the T-shaped sealing ring 700 is sealed with the piston disk by extrusion in the sealing groove of the piston disk. The end face of the outer ring 720 of the T-shaped sealing ring 700 is a circular surface, and two retaining rings 730 are configured to reinforce the outer ring 720. The T-shaped sealing ring 700 will not generate torque during the process of moving up and down with the piston disk, thereby effectively improving the service life of the sealing ring at the above position.

[0040] When opening the lift stem ball valve by pneumatic operation, as Figure 2 shown, first install the end cover 900 on the upper cover 110 to close the upper cover 110, and then ventilate the first lower chamber air source interface 121 and the second upper chamber air source interface 131 through the air source. Due to the partition and sealing effect of the upper piston disk 210 and the lower piston disk 220, the air pressure below the upper piston disk 210 and the air pressure below the lower piston disk 220 increase simultaneously. 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.

[0041] When closing the lift stem ball valve by pneumatic operation, as Figure 3 shown, first install the end cover 900 on the upper cover 110 to close the upper cover 110, and then ventilate the first upper chamber air source interface 111 and the second lower chamber air source interface 132 through the air source. Due to the partition and sealing effect of the upper piston disk 210 and the lower piston disk 220, the air pressure above the upper piston disk 210 and the air pressure above the lower piston disk 220 increase simultaneously. 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.

[0042] When opening the lift stem ball valve by manual operation, as Figure 4As shown, first remove the end cover 900 from the upper cover 110, connect the lifting rod 310 of the manual lifting mechanism to the top of the piston rod 230, and fix the nut sleeve 330 on the upper cover 110 at the same time. Then rotate 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 will abut against the thrust ball bearing 400 located above on the lifting rod 310, and then push 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.

[0043] When closing the lift rod ball valve by manual operation, as Figure 5 shown, first remove the end cover 900 from the upper cover 110, connect the lifting rod 310 of the manual lifting mechanism to the top of the piston rod 230, and fix the nut sleeve 330 on the upper cover 110 at the same time. Then rotate 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 will abut against the thrust ball bearing 400 located below on the lifting rod 310, and then push 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. A linear stroke pneumatic actuator for a rising stem ball valve, comprising a housing having a piston chamber formed by a removable upper cover (110) and a lower cover (120), wherein a piston assembly is disposed in the piston chamber of the housing, and characterized in that: The piston assembly also includes a partition (130) fixed in the shell, the partition (130) dividing the piston chamber into two upper and lower chambers; the upper cover (110) is provided with a first upper chamber air source interface (111) communicating with the upper chamber, the lower cover (120) is provided with a first lower chamber air source interface (121) communicating with the lower chamber, the partition (130) is provided with a second upper chamber air source interface (131) communicating from the outside of the shell to the upper chamber, and a second lower chamber air source interface (132) communicating from the outside of the shell to the lower chamber; the piston assembly includes The utility model comprises a piston rod (230) and an upper piston plate (210) and a lower piston plate (220) fixed on the piston rod (230), wherein the upper piston plate (210) is located in the upper chamber of the piston chamber and is sealed with the upper chamber, and the lower piston plate (220) is located in the lower chamber of the piston chamber and is sealed with the lower chamber, the piston rod (230) passes through the partition (130) and the lower end of the piston rod (230) extends out of the piston chamber, and the end of the piston rod (230) extending out of the piston chamber is a valve stem connection end; and also comprises a manual lifting mechanism detachably connected to the upper end of the piston rod (230); The manual lifting mechanism comprises a lifting rod (310), a driving screw rod (320), a nut sleeve (330) and a hand wheel (340); the lifting rod (310) is detachably connected to the upper end of the piston rod (230) and extends upward to the outside of the piston cavity; the upper cover (110) is provided with a through hole for the lifting rod (310) to pass through; the nut sleeve (330) is vertically fixed on the upper cover (110) and seals the through hole of the upper cover (110); the driving screw rod (320) is inserted into the nut sleeve (330) and The lifting rod (310) is threadedly matched with the nut sleeve (330); the driving screw rod (320) is axially provided with a through hole that is clearance-matched with the lifting rod (310); the lifting rod (310) passes through the nut sleeve (330) and the driving screw rod (320) in sequence upward; the upper and lower parts of the lifting rod (310) are provided with limiting structures that form axial limiting cooperation with the driving screw rod (320); the hand wheel (340) forms a transmission cooperation with the driving screw rod (320); rotating the hand wheel (340) can drive the driving screw rod (320) to rotate.

2. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 1, characterized in that: Thrust ball bearings (400) are installed 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 (310); the thrust ball bearing (400) located at the upper part is fixed to the installation position by means of an elastic retaining ring, and the thrust ball bearing (400) located at the lower part is fixed to the installation position by means of a nut, a spring washer and a flat washer.

3. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 1, characterized in that: One end of the driving screw rod (320) that matches with the hand wheel (340) is provided with a rectangular end head, and a matching portion is fixedly connected to the hand wheel (340), and the matching portion is provided with a rectangular limiting groove that matches with the rectangular end head of the driving screw rod (320).

4. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 3, characterized in that: It also includes an upper dust cover (510) and a lower dust cover (520) fixedly connected to the matching part of the hand wheel (340), wherein the lower dust cover (520) is fixedly connected to the lower end of the matching part and sleeved on the outside of the nut sleeve (330), and the upper dust cover (510) is fixedly connected to the upper end of the matching part and sleeved on the outside of the rectangular end head; one end of the driving screw rod (320) is provided with a rectangular end head, and a limiting convex ring is fixed to form an axial limiting fit with the matching part of the lower dust cover (520) or the hand wheel (340).

5. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 4, 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) is threadedly connected on the lower dust cover (520) and is plug-fitted with the positioning groove (610).

6. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 4, characterized in that: Sealing rings are provided between the upper piston disc (210) and the inner wall of the upper chamber, between the lower piston disc (220) and the inner wall of the lower chamber, between the piston rod (230) and the partition (130), between the piston rod (230) and the lower cover (120), between the nut sleeve (330) and the upper cover (110), and between the nut sleeve (330) and the lower dust cover (520).

7. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 6, characterized in that: The sealing ring between the upper piston disc (210) and the inner wall of the upper chamber and the sealing ring between the lower piston disc (220) and the inner wall of the lower chamber are both T-shaped sealing rings (700); the cross section of the T-shaped sealing ring (700) is T-shaped, and the T-shaped sealing ring (700) is composed of a bottom ring (710) and an outer ring (720) connected to the middle part of the outer side of the bottom ring (710), and the end face of the outer ring (720) is a circular face; the upper piston disc (210) and the lower piston disc (220) are provided with sealing grooves that form an interlocking fit with the bottom ring (710), and the sealing grooves are also provided with retaining rings (730) that fill the upper and lower parts of the outer ring (720).

8. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 1, characterized in that: It also includes a stroke indicating rod (810) detachably connected to the lower piston plate (220); 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 out of the piston cavity.

9. The linear stroke pneumatic actuator for a rising stem ball valve according to claim 1, characterized in that: The valve stem connecting end of the piston rod (230) is provided with an internal threaded hole, a guide key (231) is installed on the outer peripheral surface of the piston rod (230), and a key groove matched with the guide key (231) is provided on the lower cover (120).

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