CN116989151A

CN116989151A - Multi-section controlled pneumatic stop valve

Info

Publication number: CN116989151A
Application number: CN202311254620.3A
Authority: CN
Inventors: 靳明伟; 戴继新; 窦聪; 姜秋月; 邓明旺
Original assignee: Fiter Valve Manufacturer Co ltd
Current assignee: Fiter Valve Manufacturer Co ltd
Priority date: 2023-09-27
Filing date: 2023-09-27
Publication date: 2023-11-03
Anticipated expiration: 2043-09-27
Also published as: CN116989151B

Abstract

The invention discloses a pneumatic stop valve controlled by multiple sections, which relates to the technical field of valves and comprises a valve body, wherein a baffle seat is arranged in the valve body, a circulation opening is formed in the baffle seat, a cylinder is arranged on the valve body and comprises a cylinder body, a first piston cavity, a first piston and a first piston rod are arranged in the cylinder body, the outer end of the first piston rod extends into the valve body and is fixedly connected with a valve clack, a plug is fixedly connected with the bottom surface of the valve clack, a first annular groove is formed in the surface of the plug, a first annular air bag is connected in the first annular groove, and a second annular groove is formed in the inner wall of the circulation opening; the connecting rod is fixedly connected in the first piston cavity, the second piston is fixedly connected at the bottom end of the connecting rod, the second piston cavity is arranged in the first piston rod, the second piston is connected in a sealing sliding mode to the second piston cavity, the second piston cavity is partitioned into a first upper cavity and a first lower cavity, a first channel is arranged in the first piston rod, and the first channel is communicated with the first upper cavity and the first annular air bag. The invention adopts the composite seal of the pressing seal and the air bag seal, thereby improving the sealing effect.

Description

Multi-section controlled pneumatic stop valve

Technical Field

The invention relates to the technical field of valves, in particular to a pneumatic stop valve with multi-section control.

Background

The pneumatic stop valve is a stop valve which drives the valve clack to open and close through the air cylinder, the valve clack is tightly pressed on a baffle plate seat in the inner cavity of the valve body, the valve is closed, the current pneumatic stop valve only has two actions of opening and closing, the valve seal is realized only by the pressing and sealing of the valve clack and the baffle plate seat, and once the sealing layer on the bottom surface of the valve clack is worn, the valve directly loses the closure performance;

especially for large-scale valves, the required sealing peripheral area is large, the abrasion condition of the sealing layer is easy to occur, the pressure of the inflow end of the valve is large, the valve clack can be driven to slightly move by the inflow pressure, and the sealing performance can be directly influenced.

Disclosure of Invention

The invention aims to provide a pneumatic stop valve controlled by multiple sections, and aims to solve the technical problem that the pneumatic stop valve in the prior art is poor in sealing performance.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the utility model provides a pneumatic stop valve of multistage control, including the valve body, be equipped with the baffle seat in the valve body, be equipped with the circulation opening on the baffle seat, be equipped with the valve clack that is used for shutoff circulation opening in the valve body, install the cylinder on the valve body, the cylinder includes the cylinder body, be equipped with first piston chamber in the cylinder body, sealed sliding connection has first piston in the first piston chamber, first piston bottom rigid coupling has first piston rod, the outer end of first piston rod extends to in the valve body, and rigid coupling valve clack, the valve clack bottom surface rigid coupling has the cock stem, the cock stem side is equipped with first ring channel, be connected with first annular gasbag in the first ring channel, the circulation opening inner wall is equipped with the second ring channel, along with valve clack pressure baffle seat, cock stem clearance fit is in the circulation opening, first ring channel and second ring channel are just to setting; the first piston cavity is internally provided with a connecting rod, the top end of the connecting rod is fixedly connected with a cylinder body, the bottom end of the connecting rod is fixedly connected with a second piston, the connecting rod is in sealing sliding connection with the first piston and the first piston rod, the first piston rod is internally provided with a second piston cavity, the second piston is in sealing sliding connection with the second piston cavity and partitions the second piston cavity into a first upper cavity and a first lower cavity, a first channel is arranged in the first piston rod, one end of the first channel is communicated with the first upper cavity, the other end of the first channel extends to a plug, and the first channel is communicated with a first annular air bag.

Wherein, establish confined first installing chamber in the first piston rod, be equipped with the control valve subassembly in the first installing chamber, the control valve subassembly includes check valve and relief valve, and check valve and relief valve establish ties in first passageway through the pipe fitting respectively, and the check valve is parallelly connected with the relief valve and is set up, and check valve control fluid is by first annular gasbag to first upper chamber unidirectional flow, and relief valve control fluid is by first upper chamber to first annular gasbag unidirectional flow.

Wherein the inner wall of the second annular groove is covered with a flexible layer.

The flexible layer is a second annular air bag, a third piston cavity is arranged in the partition plate seat, a third piston is connected in a sealing sliding manner in the third piston cavity, the third piston partitions the third piston cavity into a second upper cavity and a second lower cavity, a second channel is arranged in the partition plate seat, and the second channel is communicated with the second upper cavity and the second annular air bag; the second lower cavity is internally provided with a first spring for driving the third piston to move upwards, the top surface of the third piston is vertically fixedly connected with a third piston rod, and the third piston rod is in sealing sliding connection with the partition plate seat and penetrates through the top surface of the partition plate seat in a sliding manner.

The plug bottom surface is coaxially and slidably connected with a first sliding column, the bottom end of the first sliding column is fixedly connected with a connecting plate, a third annular air bag is connected between the top surface of the connecting plate and the bottom surface of the plug in a sealing manner, a third channel is arranged in the plug, and the third channel is communicated with the first annular air bag and the third annular air bag.

Wherein, the second annular groove is internally provided with an annular bulge; a sliding cavity is arranged in the valve clack, a moving block is vertically and slidably connected in the sliding cavity, a second sliding column is fixedly connected to the bottom surface of the moving block, the second sliding column penetrates through the bottom surface of the valve clack in a sliding mode, and a second spring for driving the moving block to move downwards is arranged in the sliding cavity; the plug is internally provided with a second installation chamber, the first channel is communicated with the sliding cavity and the second installation chamber, a pull rope is penetrated in the first channel, one end of the pull rope is hinged to the middle position of the inner wall of the first annular air bag, the other end of the pull rope is hinged to the bottom surface of the moving block, a guide wheel is installed in the second installation chamber, and the pull rope is connected to the guide wheel in a guiding way; the stay cord is equipped with a plurality of, and a plurality of stay cords are the circumference and are arranged around the cock stem.

The first channel comprises a vertical channel, the vertical channel is communicated with the sliding cavity and the second installation chamber, a fourth piston is connected in the vertical channel in a sealing sliding manner, and the fourth piston is coaxially and fixedly connected to the pull rope.

After the technical scheme is adopted, the invention has the beneficial effects that:

1. according to the invention, multistage control is realized through the air cylinder, so that a composite sealing system of pressing seal and air bag seal is formed, and the sealing effect is effectively improved.

2. The air bag sealing action response of the invention is timely and accurate, and the abrasion of parts is effectively avoided.

3. When the air bag sealing structure is subjected to fluid pressure, the secondary inflation of the first annular air bag can be realized, and the larger the fluid pressure is, the larger the expansion amount of the first annular air bag is, and the higher the sealing compactness is.

4. The air bag sealing structure provided by the invention avoids the accumulation of impurities in the fluid and increases the sealing area.

Drawings

FIG. 1 is a longitudinal cross-sectional view of a first embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of a second embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 4 is a partial cross-sectional view of a valve in a third embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 5 is a partial cross-sectional view of a valve in a third embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 6 is a partial cross-sectional view of a fourth embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 7 is a partial cross-sectional view of a fifth embodiment of a multi-stage controlled pneumatic shut-off valve of the present invention;

FIG. 8 is an enlarged view of portion B of FIG. 7;

in the figure, the valve body 1, the flange joint 10, the diaphragm seat 2, the flow opening 20, the second annular groove 21, the second annular airbag 22, the second closed air chamber 220, the second upper chamber 23, the second lower chamber 24, the third piston 25, the second passage 26, the first spring 27, the third piston rod 28, the annular protrusion 29, the valve flap 3, the spool 30, the moving block 31, the second spool 32, the second spring 33, the vertical passage 34, the fourth piston 35, the plug 4, the first annular groove 40, the first closed air chamber 400, the first annular airbag 41, the first spool 42, the connection plate 43, the third annular airbag 44, the third passage 45, the second installation chamber 46, the guide wheel 47, the pull cord 48, the cylinder 5, the cylinder body 50, the first piston chamber 500, the first piston 51, the first piston rod 52, the first upper chamber 520, the first lower chamber 521, the first passage 522, the first installation chamber 523, the check valve, the pressure release valve 524, the connection rod 525, the second piston 54.

Detailed Description

The invention is further elucidated below in conjunction with the accompanying drawings.

The orientations referred to in the present specification are all based on the orientations of the multistage-controlled pneumatic stop valve of the present invention when the valve is normally operated, and are not limited to orientations during storage and transportation, but only represent relative positional relationships, and not absolute positional relationships.

Example 1

As shown in fig. 1 and fig. 2 together, the pneumatic stop valve with multi-section control comprises a valve body 1, wherein an inner cavity is arranged in the valve body 1, flange joints 10 are arranged at two ends of the valve body 1, a baffle seat 2 for blocking the inner cavity is arranged in the valve body 1, a vertically arranged circulation opening 20 is formed in the baffle seat 2, fluid enters the inner cavity through the flange joint 10 at one end of the valve body 1, then passes through the circulation opening 20 and flows out from the flange joint 10 at the other end of the valve body 1.

The cylinder 5 is installed at valve body 1 top, cylinder 5 vertical setting, cylinder 5 includes cylinder body 50, the top and the bottom of cylinder body 50 all are equipped with the business turn over air port, be equipped with first piston chamber 500 in the cylinder body 50, vertical sealed sliding connection has first piston 51 in the first piston chamber 500, the vertical rigid coupling in bottom of first piston 51 has first piston rod 52, extend to the inner chamber after the bottom seal of first piston rod 52 passes cylinder body 50 bottom, and the valve clack 3 in the rigid coupling inner chamber, valve clack 3 bottom surface is equipped with the sealing layer, along with first piston 51 moves down, valve clack 3 presses the baffle seat 2 top surface, and cover circulation opening 20, realize valve closure.

The bottom surface of the valve clack 3 is coaxially and fixedly connected with a plug 4, in this embodiment, the valve clack 3 and the plug 4 are cast integrally, the plug 4 is in clearance fit with the circulation opening 20, the surface of the plug 4 is provided with a first annular groove 40, the first annular groove 40 extends around the axial direction of the plug 4, the first annular groove 40 is provided with a plurality of first annular grooves 40, and the plurality of first annular grooves 40 are arranged at intervals along the axial direction of the plug 4. The inner wall of the circulation opening 20 is provided with a second annular groove 21, and a plurality of second annular grooves 21 are arranged and are horizontally opposite to the first annular grooves 40 one by one.

The first annular groove 40 is connected with the first annular air bag 41, in this embodiment, the cross section of the first annular air bag 41 is arc-shaped, that is, the first annular air bag 41 is open, the inner ring side of the first annular air bag 41 is open and is in butt joint with the opening of the first annular groove 40, so that a first closed air cavity 400 is formed between the first annular air bag 41 and the first annular groove 40. In other modes, the cross section of the first annular air bag 41 is circular, namely the first annular air bag 41 is closed, a first closed air cavity 400 is formed in the first annular air bag 41, the first annular air bag 41 is sleeved in the first annular groove 40, and the inner ring side of the first annular air bag 41 is adhered to the groove wall of the first annular groove 40.

The first piston cavity 500 is internally provided with a connecting rod 53, the top end of the connecting rod 53 is fixedly connected to the top surface of the first piston cavity 500, and the bottom end of the connecting rod 53 is coaxially fixedly connected with a second piston 54.

The connecting rod 53 and the first piston 51 are coaxially arranged, a second piston cavity is arranged in the first piston rod 52, the bottom end of the connecting rod 53 penetrates through the first piston 51 in a sliding mode and extends into the second piston cavity, the second piston 54 is vertically connected in a sliding mode in the second piston cavity in a sealing mode and is separated into a first upper cavity 520 and a first lower cavity 521, a first channel 522 is arranged in the first piston rod 52, one end port of the first channel 522 is communicated with the first upper cavity 520, the other end of the first channel 522 extends to the plug 4 and is communicated with the first closed air cavity 400.

When the valve is closed, the cylinder 5 drives the first piston rod 52 to move downwards, so that the valve clack 3 moves downwards synchronously, the valve clack 3 is tightly pressed on the top surface of the partition seat 2, thereby closing the circulation opening 20, and the plug 4 enters the circulation opening 20.

Simultaneously with the downward movement of the first piston rod 52, the second piston 54 compresses the first upper chamber 520 such that the gas in the first upper chamber 520 enters the first closed air chamber 400 through the first passage 522, causing the first annular bladder 41 to inflate and fill the second annular groove 21. The expansion type sealing is realized, and the sealing performance is effectively improved.

When the valve is opened, the cylinder 5 drives the first piston rod 52 to move upwards, the valve clack 3 moves upwards synchronously, the second piston 54 compresses the first lower cavity 521, the first upper cavity 520 becomes larger in volume, and accordingly gas in the first closed air cavity 400 is pumped out, the first annular air bag 41 is exhausted and contracted, and the first annular air bag 41 is contained in the first annular groove 40. The communication between the flow openings 20 is achieved, at the same time, friction between the first annular air pocket 41 and the walls of the second annular groove 21 is avoided, and the wear of the components is reduced.

Example two

The difference between this embodiment and the first embodiment is that, as shown in fig. 3, a closed first installation chamber 523 is provided in the first piston rod 52, a control valve assembly is installed in the first installation chamber 523, the control valve assembly includes a check valve 524 and a relief valve 525, the check valve 524 and the relief valve 525 are respectively connected in series to the first channel 522 through pipes, and the check valve 524 is connected in parallel to the relief valve 525, the check valve 524 controls the unidirectional flow of fluid from the first annular air bag 41 to the first upper chamber 520, and the relief valve 525 controls the unidirectional flow of fluid from the first upper chamber 520 to the first annular air bag 41.

When the first annular bladder 41 is inflated, the second piston 54 compresses the first upper chamber 520 and the pressure of the compressed gas gradually increases, and when the plug 4 enters the flow opening 20, the pressure of the compressed gas reaches a critical point of a preset pressure value of the relief valve 525, thereby driving the relief valve 525 to open, the compressed gas rapidly enters the first closed air chamber 400, so that the second annular bladder 22 rapidly expands and fills the second annular groove 21.

When the first annular air bag 41 is exhausted, the second piston 54 compresses the first lower chamber 521, thereby pumping out the air in the first annular air bag 41 at the first time, and the pumped-out air flows into the first upper chamber 520 through the check valve 524.

Through the unidirectional control function of the control valve assembly, the expansion and contraction of the first annular air bag 41 are both generated in the time period of the cooperation of the plug 4 and the circulation opening 20, so that the action response of the first annular air bag 41 is more accurate and timely. Further avoiding wear of the first annular bladder 41.

Example III

The difference between this embodiment and the second embodiment is that, as shown in fig. 4 and 5, the inner wall of the second annular groove 21 is covered with a flexible layer, and the first annular air bag 41 is more tightly abutted against the flexible layer when expanding, so that the sealing effect is better.

Preferably, the flexible layer is a second annular bladder 22, and a second closed air chamber 220 is formed between the second annular bladder 22 and the second annular groove 21.

The partition plate seat 2 is provided with a third piston cavity, a third piston 25 is vertically and hermetically connected in the third piston cavity in a sliding manner, the third piston 25 partitions the third piston cavity into a second upper cavity 23 and a second lower cavity 24, the partition plate seat 2 is internally provided with a second channel 26, and the second channel 26 is communicated with the second upper cavity 23 and the second annular air bag 22;

the second lower chamber 24 is internally provided with a first spring 27, the first spring 27 is elastically supported between the bottom surface of the second lower chamber 24 and the bottom surface of the third piston 25, and the third piston 25 is driven to move upwards by the first spring 27.

The top surface of the third piston 25 is vertically fixedly connected with a third piston rod 28, the third piston rod 28 is in sealing sliding connection with the partition plate seat 2, and the top end of the third piston rod 28 penetrates through the top surface of the partition plate seat 2 in a sliding manner.

In the initial state, the first spring 27 drives the third piston 25 to move to the topmost position, and the gas in the second upper cavity 23 fills the second closed air cavity 220, so that the second annular air bag 22 is inflated, and the concave area of the second annular groove 21 is filled up, thereby avoiding the phenomenon that when the fluid containing impurities flows through the circulation opening 20, the impurities are accumulated in the second annular groove 21 and influence the normal use of the valve.

When the valve is closed, the valve clack 3 is pressed against the top surface of the partition plate seat 2, so that the third piston rod 28 is pressed down, the third piston 25 compresses the second lower cavity 24, the pressure in the second upper cavity 23 is reduced, the gas in the second annular air bag 22 is partially extracted, the second annular air bag 22 is concave, the first annular air bag 41 is expanded into the second annular groove 21, the first annular air bag 41 and the second annular air bag 22 are mutually abutted, tight abutment is formed, and the tightness is further improved.

Example IV

The difference between this embodiment and the second embodiment is that, as shown in fig. 6, the bottom surface of the plug 4 is coaxially and slidably connected with a first sliding column 42, a connecting plate 43 is fixedly connected with the bottom end of the first sliding column 42, the connecting plate 43 is located below the plug 4, a third annular air bag 44 is sealingly connected between the top surface of the connecting plate 43 and the bottom surface of the plug 4, the third annular air bag 44 is coaxially sleeved outside the first sliding column 42, a third channel 45 is provided in the plug 4, and the third channel 45 communicates the first annular air bag 41 and the third annular air bag 44.

After the plug 4 enters the circulation opening 20, the fluid pressure in the valve body 1 acts on the connecting plate 43 to drive the connecting plate 43 to move upwards by a certain distance, so that the gas in the third annular air bag 44 is pressed into the first annular air bag 41, the second inflation of the first annular air bag 41 is realized, when the fluid pressure is larger, the second inflation amount of the first annular air bag 41 is also larger, the inflation amount of the first annular air bag 41 is increased, the filling in the second annular groove 21 is more compact, and the sealing effect is further improved.

Example five

The present embodiment is different from the second embodiment in that, as shown in fig. 7 and 8 in common, an annular protrusion 29 is provided inside the second annular groove 21, and the annular protrusion 29 increases the inner wall area of the second annular groove 21.

The valve clack 3 is internally provided with a sliding cavity 30, the sliding cavity 30 is vertically connected with a moving block 31 in a sliding manner, the bottom surface of the moving block 31 is fixedly connected with a second sliding column 32, the second sliding column 32 penetrates through the bottom surface of the valve clack 3 in a sliding manner, at least two second sliding columns 32 are arranged in a circumferential arrangement mode around the valve clack 3, the sliding cavity 30 is internally provided with a second spring 33, the second spring 33 is elastically supported between the top surface of the sliding cavity 30 and the top surface of the moving block 31, the moving block 31 is driven to move downwards through the second spring 33, the second spring 33 is provided with a plurality of second springs 33, and the second springs 33 are circumferentially arranged around the moving block 31.

The plug 4 is internally provided with a second installation chamber 46, the first channel 522 is communicated with the sliding cavity 30 and the second installation chamber 46, the pull rope 48 is penetrated in the first channel 522, the pull rope 48 is coaxially sleeved in the first channel 522, a first shackle is arranged in the middle of the inner wall of the first annular air bag 41, the bottom surface of the moving block 31 is provided with a second shackle, one end of the pull rope 48 is tied on the first shackle, and the other end of the pull rope 48 penetrates through the second installation chamber 46 and the sliding cavity 30 and is tied on the second shackle.

The second installation chamber 46 is internally provided with a guide wheel 47, and the stay ropes 48 are connected to the guide wheel 47 in a guiding way, so that the stay ropes 48 are changed from transverse movement to vertical movement under the guiding of the guide wheel 47, a plurality of stay ropes 48 are arranged, and the plurality of stay ropes 48 are circumferentially arranged around the plug 4.

In the process that the valve clack 3 is pressed against the baffle seat 2, the second sliding column 32 is blocked by the top surface of the baffle seat 2 and moves upwards, so that the moving block 31 moves upwards synchronously, and the pull rope 48 is pulled, so that the middle of the first annular air bag 41 receives a pulling force to deform, the outer annular surface of the first annular air bag 41 is concave, and the fit with the annular bulge 29 to form accurate tight fit, the sealing area is increased, and the sealing performance is further improved.

The annular bulge 29 can be clamped after the first annular air bag 41 is concavely deformed, so that a high sealing effect is realized, and meanwhile, the first annular air bag 41 is prevented from being filled in a concaved area on one side inside the second annular groove 21 in a staggered manner, and a cavity is formed in the concaved area on the other side, so that sealing is not tight.

Further, the first passage 522 includes a vertical passage 34, the vertical passage 34 communicates the sliding cavity 30 with the second installation chamber 46, a fourth piston 35 is connected in the vertical passage 34 in a sealing sliding manner, the fourth piston 35 is coaxially and fixedly connected to the pull rope 48, and the second installation chamber 46 is separated from the sliding cavity 30 by the fourth piston 35, so that the influence of the pressure change in the sliding cavity 30 on the pressure in the second installation chamber 46 is reduced when the moving block 31 moves vertically. When the pull rope 48 acts, the fourth piston 35 slides vertically synchronously, so that the stability of the action of the pull rope 48 is improved.

The present invention is not limited to the above-described specific embodiments, and various modifications may be made by those skilled in the art without inventive effort from the above-described concepts, and are within the scope of the present invention.

Claims

1. The utility model provides a pneumatic stop valve of multistage control, includes the valve body, be equipped with the baffle seat in the valve body, be equipped with the circulation opening on the baffle seat, be equipped with the valve clack that is used for shutoff circulation opening in the valve body, install the cylinder on the valve body, the cylinder includes the cylinder body, be equipped with first piston chamber in the cylinder body, sealed sliding connection has first piston in the first piston chamber, first piston bottom rigid coupling has first piston rod, the outer end of first piston rod extends to in the valve body, and rigid coupling valve clack, its characterized in that,

the bottom surface of the valve clack is fixedly connected with a plug, the side surface of the plug is provided with a first annular groove, a first annular air bag is connected in the first annular groove, the inner wall of the circulation opening is provided with a second annular groove, the plug is in clearance fit with the circulation opening along with the valve clack pressing against the baffle seat, and the first annular groove and the second annular groove are opposite to each other;

the connecting rod is fixedly connected to the cylinder body at the top end of the connecting rod, the second piston is fixedly connected to the bottom end of the connecting rod, the connecting rod is in sealing sliding connection with the first piston and the first piston rod, the second piston cavity is arranged in the first piston rod, the second piston is in sealing sliding connection with the second piston cavity and is separated into a first upper cavity and a first lower cavity, a first channel is arranged in the first piston rod, one end of the first channel is communicated with the first upper cavity, the other end of the first channel is extended to the plug, and the first channel is communicated with a first annular air bag.

2. The multi-section controlled pneumatic stop valve as claimed in claim 1, wherein a closed first installation chamber is arranged in the first piston rod, a control valve assembly is arranged in the first installation chamber, the control valve assembly comprises a one-way valve and a pressure release valve, the one-way valve and the pressure release valve are respectively connected in series with the first channel through pipe fittings, the one-way valve and the pressure release valve are arranged in parallel, the one-way valve controls fluid to flow unidirectionally from the first annular air bag to the first upper cavity, and the pressure release valve controls fluid to flow unidirectionally from the first upper cavity to the first annular air bag.

3. A multi-segment controlled pneumatic shut-off valve as in claim 2 wherein said second annular groove inner wall is covered with a flexible layer.

4. A multi-section controlled pneumatic stop valve as claimed in claim 3 wherein the flexible layer is a second annular air bag, a third piston chamber is provided in the diaphragm seat, a third piston is connected in a sealing sliding manner in the third piston chamber, the third piston partitions the third piston chamber into a second upper chamber and a second lower chamber, a second channel is provided in the diaphragm seat, and the second channel communicates the second upper chamber with the second annular air bag;

the second lower cavity is internally provided with a first spring for driving the third piston to move upwards, the top surface of the third piston is vertically and fixedly connected with a third piston rod, and the third piston rod is in sealing sliding connection with the partition plate seat and penetrates through the top surface of the partition plate seat in a sliding manner.

5. The multi-section controlled pneumatic stop valve of claim 2, wherein the bottom surface of the plug is coaxially and slidably connected with a first sliding column, a connecting plate is fixedly connected to the bottom end of the first sliding column, a third annular air bag is hermetically connected between the top surface of the connecting plate and the bottom surface of the plug, a third channel is arranged in the plug, and the third channel is communicated with the first annular air bag and the third annular air bag.

6. A multi-stage controlled pneumatic shut-off valve as in claim 2 wherein said second annular groove has an annular projection therein;

a sliding cavity is arranged in the valve clack, a moving block is vertically and slidably connected in the sliding cavity, a second sliding column is fixedly connected to the bottom surface of the moving block, the second sliding column penetrates through the bottom surface of the valve clack in a sliding mode, and a second spring for driving the moving block to move downwards is arranged in the sliding cavity;

the plug is internally provided with a second installation chamber, the first channel is communicated with the sliding cavity and the second installation chamber, a pull rope is installed in the first channel in a penetrating way, one end of the pull rope is hinged to the middle position of the inner wall of the first annular air bag, the other end of the pull rope is hinged to the bottom surface of the moving block, a guide wheel is installed in the second installation chamber, and the pull rope is connected to the guide wheel in a guiding way;

the stay cord is equipped with a plurality of, and a plurality of stay cords are the circumference and are arranged around the cock stem.

7. The multi-segment controlled pneumatic shut-off valve of claim 6 wherein the first passage comprises a vertical passage communicating the sliding chamber with the second mounting chamber, a fourth piston sealingly and slidingly connected within the vertical passage, the fourth piston coaxially secured to the pull cord.