CN112324936A

CN112324936A - Flat gate valve

Info

Publication number: CN112324936A
Application number: CN202011187163.7A
Authority: CN
Inventors: 张柏; 尹肖飞; 其他发明人请求不公开姓名
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2021-02-05

Abstract

The invention relates to a flat gate valve which comprises a valve body, a gate plate and a gate plate controller, wherein the valve body is provided with a flow passage, a middle chamber, an upper chamber and a lower chamber are arranged in the valve body, the gate plate controller comprises a driving device and a valve rod, the flow passage is in a conducting state when the driving device drives the gate plate to enter the upper chamber, the flow passage is in a stopping state when the driving device drives the gate plate to enter the lower chamber, and the flat gate valve further comprises a mud pushing protection mechanism used for scraping mud on the side position of the gate plate. The mud pushing protection mechanism is arranged, when the flashboard is opened, three mud pushing plates in the mud pushing protection mechanism sequentially move to the connecting edge between the middle cavity and the runner from bottom to top, then the mud in the middle cavity is pushed to the position of the runner, mud media can be prevented from being retained in the middle cavity, and when the flashboard is closed, the three mud pushing plates sequentially retract to the original position from top to bottom and are in contact with the side edge of the flashboard, so that the flashboard can be prevented from being damaged due to the influence of the mud.

Description

Flat gate valve

Technical Field

The invention belongs to the technical field of pipeline valves, and particularly relates to a flat gate valve.

Background

The wellhead device and the Christmas tree are important equipment for oil and gas exploitation, and comprise a casing head, a tubing head and a Christmas (gas) tree, which are used for connecting casing strings and tubing strings and sealing annular spaces among various layers of casings and among oil pipes, controlling the pressure of a production wellhead and regulating the flow of the oil (gas) wellhead, and can also be used for special operations such as acidizing fracturing, water injection, testing and the like. On oil gas field wellhead assembly and production tree, the medium of effect is mud, and traditional type high pressure plate valve is in the use, and its mud can get into the well cavity of valve body to the adhesion is at this well cavity lateral wall, and the removal route when leading to the flashboard to close is obstructed, destroys the flashboard easily.

Disclosure of Invention

In view of the above, it is desirable to provide a flat gate valve having a reasonable structure and preventing a slurry medium from being accumulated in a middle chamber side position.

The invention discloses a flat gate valve, which comprises a valve body, a gate plate and a gate plate controller, wherein the valve body is provided with a flow passage communicated or separated by the gate plate, a middle cavity communicated with the flow passage is arranged at the position of the gate plate in the valve body, an upper cavity communicated with the middle cavity is arranged above the gate plate in the valve body, a lower cavity communicated with the middle cavity is arranged below the gate plate in the valve body, the gate plate controller is arranged in linkage with the gate plate, the gate plate controller comprises a driving device for lifting the gate plate and a valve rod for connecting the driving device with the gate plate, when the driving device drives the gate plate to enter the upper cavity, the flow passage is in a conducting state, when the driving device drives the gate plate to enter the lower cavity, the flow passage is in a stopping state, and the flat gate valve also comprises a mud pushing protection mechanism, the mud pushing protection mechanism comprises: the valve rod penetrates through the piston cavity, a movable piston which is in sliding connection with the inner wall of the piston cavity is fixedly connected to the valve rod, and the movable piston divides the piston cavity into a first piston cavity and a second piston cavity which is located above the first piston cavity; two groups of mud pushing cavity groups are symmetrically arranged on two sides of the valve body, which are positioned in the middle cavity, each group of mud pushing cavity group comprises a first mud pushing cavity, a second mud pushing cavity positioned above the first mud pushing cavity and a third mud pushing cavity positioned above the second mud pushing cavity, the first mud pushing cavity, the second mud pushing cavity and the third mud pushing cavity are respectively and slidably connected with a first slide block, a second slide block and a third slide block, the first slide block separates the first mud pushing cavity into a first inner cavity close to one side of the middle cavity and a first outer cavity far away from one side of the middle cavity, the second slide block separates the second mud pushing cavity into a second inner cavity close to one side of the middle cavity and a second outer cavity far away from one side of the middle cavity, and the third slide block separates the third mud pushing cavity into a third inner cavity close to one side of the middle cavity and a third outer cavity far away from one side of the middle cavity, the second slider lateral surface is seted up and is close to the first annular of well cavity one side and is located the second annular in the first annular outside, the third slider lateral surface is seted up and is close to the third annular of well cavity one side and is located the fourth annular in the third annular outside, the inboard upper end of first inner chamber the outside terminal surface of first outer cavity respectively with the second pushes away mud chamber intercommunication and has first air guide channel and second air guide channel, and works as the second slider removes when the second pushes away mud chamber outermost end, first air guide channel with first annular is linked together, second air guide channel with the second annular communicates mutually, the inboard upper end of second inner chamber the upper surface middle part inboard of second push away mud chamber communicate jointly have with the third air guide channel that third pushed away mud chamber intercommunication, the outside terminal surface of second inner chamber, The second pushes away the upper surface middle part outside in mud chamber and communicates together with the third pushes away the fourth air guide passageway in mud chamber intercommunication, and when the second slider, the third slider moves respectively the second pushes away mud chamber, when the third pushes away the outermost end in mud chamber, first annular with the third annular is linked together, the second annular with the fourth annular communicates mutually, the inboard upper end in third inner chamber, the upper surface middle part inboard in third pushes away the mud chamber communicates together with the fifth air guide passageway that communicates with first piston cavity, the outer end face in third inner chamber, the upper surface middle part outside in third pushes away the mud chamber communicates together with the sixth air guide passageway that communicates with second piston cavity, and when the third slider moves the outer end in third pushes away the mud chamber, the fifth air guide passageway with the third annular is linked together, the sixth air guide channel is communicated with the fourth ring groove; two sets of mud pushing plate groups, symmetrical sliding connection in the middle cavity, every group mud pushing plate group including first mud pushing plate, be located the second mud pushing plate of first mud pushing plate top and be located the third mud pushing plate of second mud pushing plate top, first slider the second slider with the inner of third slider respectively with first mud pushing plate, the second mud pushing plate third mud pushing plate fixed connection is used for driving mud pushing plate group slides in the middle cavity.

In one embodiment, the piston further comprises two check valves, the check valves are respectively installed in the two fifth air guide channels and used for stopping the flow direction of the third inner cavity to the first piston cavity, each check valve comprises a valve core and a first return spring, through holes communicated with the fifth air guide channels are formed in two side walls of the upper cavity, and one end, far away from the first return spring, of the valve core penetrates through the through holes and extends into the upper cavity.

In one embodiment, the valve body comprises an upper valve body and a lower valve body, the lower chamber, the middle chamber and the upper chamber are arranged in the lower valve body, and the piston cavity is arranged in the upper valve body.

In one embodiment, a lifting mud pushing plate is slidably connected in the lower chamber, and a plurality of second return springs are fixedly connected between the lifting mud pushing plate and the bottom surface of the lower chamber.

In one embodiment, the driving device is a handwheel, and the upper part of the upper valve body is in threaded connection with the upper part of the valve rod.

The technical scheme has the advantages that:

the mud pushing plate group is arranged, when the flashboard is opened, three mud pushing plates in the mud pushing plate group sequentially move to the connecting edge between the middle cavity and the runner from bottom to top, then mud in the middle cavity is pushed out to the position of the runner, mud media can be prevented from being retained in the middle cavity, and when the flashboard is closed, the three mud pushing plates sequentially retract to the original position from top to bottom and are in contact with the side edge of the flashboard, so that the flashboard can be prevented from being damaged due to the influence of the mud.

Drawings

FIG. 1 is a cross-sectional view of the shutter of the present invention in a fully closed position;

FIG. 2 is a cross-sectional view A-A of FIG. 1;

FIG. 3 is a cross-sectional view B-B of FIG. 1;

FIG. 4 is a first sectional view of the shutter of the present invention in an open state;

FIG. 5 is a second sectional view of the shutter of the present invention in an open state;

fig. 6 is a sectional view of the shutter of the present invention in a fully opened state.

In the figure, a lower valve body 1, a lower cavity 11, a middle cavity 12, an upper cavity 13, a flow passage 14, a first air guide channel 15, a second air guide channel 16, a third air guide channel 17, a fourth air guide channel 18, a first outer cavity 1a1, a first inner cavity 1b1, a second outer cavity 1a2, a second inner cavity 1b2, a third outer cavity 1a3, a third inner cavity 1b3, an upper valve body 2, a second piston cavity 2a, a first piston cavity 2b, a sixth air guide channel 201, the hydraulic control valve comprises a fifth air guide channel 202, a valve rod 3, a movable piston 31, a gate plate 4, a first slide block 51, a second slide block 52, a second annular groove 521, a first annular groove 522, a third slide block 53, a fourth annular groove 531, a third annular groove 532, a first mud pushing plate 61, a second mud pushing plate 62, a third mud pushing plate 63, a first return spring 70, a valve core 71, a driving device 8, a lifting mud pushing plate 9 and a second return spring 91.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

A flat gate valve, as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6, comprises a valve body, a gate plate 4, and a gate plate controller, wherein the valve body is provided with a flow passage 14 communicated or blocked by the gate plate 4, a middle chamber 12 communicated with the flow passage 14 is arranged at the position of the gate plate 4 in the valve body, an upper chamber 13 communicated with the middle chamber 12 is arranged above the gate plate 4 in the valve body, a lower chamber 11 communicated with the middle chamber 12 is arranged below the gate plate 4 in the valve body, the gate plate controller is arranged in linkage with the gate plate 4, the gate plate controller comprises a driving device 8 for lifting the gate plate 4 and a valve rod 3 for connecting the driving device 8 with the gate plate 4, when the driving device 8 drives the gate plate 4 to enter the upper chamber 13, the flow passage 14 is in a conducting state, the drive arrangement 8 drive flashboard 4 gets into when cavity 11 down, runner 14 is in the off-state, the plate valve still including pushing away mud protection mechanism, it includes to push away mud protection mechanism: the valve rod 3 penetrates through the piston cavity, a movable piston 31 in sliding connection with the inner wall of the piston cavity is fixedly connected to the valve rod 3, and the movable piston 31 divides the piston cavity into a first piston cavity 2b and a second piston cavity 2a located above the first piston cavity 2 b; two sets of mud pushing cavity groups are symmetrically arranged on two sides of the middle cavity 12, each group of mud pushing cavity groups comprises a first mud pushing cavity, a second mud pushing cavity and a third mud pushing cavity, the first mud pushing cavity is arranged on the second mud pushing cavity and the third mud pushing cavity is arranged on the second mud pushing cavity, the first mud pushing cavity is arranged on the second mud pushing cavity and the third mud pushing cavity is respectively and slidably connected with a first sliding block 51, a second sliding block 52 and a third sliding block 53, the first sliding block 51 is used for separating the first mud pushing cavity into a first inner cavity 1b1 on one side of the middle cavity 12 and keeping away from the first outer cavity 1a1 on one side of the middle cavity 12, the second sliding block 52 is used for separating the second mud pushing cavity into a second inner cavity 1b2 on one side of the middle cavity 12 and keeping away from the second outer cavity 1a2 on one side of the middle cavity 12, and the third sliding block 53 is used for separating the third mud pushing cavity into a third inner cavity 3 on one side of the middle cavity 12 and keeping away from the middle cavity 3 The third outer chamber 1a3 of room 12 one side, second slider 52 lateral surface is seted up and is close to first annular 522 of well chamber 12 one side and is located the second annular 521 in the first annular 522 outside, third slider 53 lateral surface is seted up and is close to third annular 532 of well chamber 12 one side and is located the fourth annular 531 in the third annular 532 outside, the inboard upper end of first inner chamber 1b1, the outside terminal surface of first outer chamber 1a1 respectively with the second pushes away mud chamber intercommunication has first air guide channel 15 and second air guide channel 16, and works as the second slider 52 moves when the second pushes away mud chamber outermost end, first air guide channel 15 with first annular 522 is linked together, second air guide channel 16 with second annular 521 is linked together, the inboard upper end of second inner chamber 1b2, the inboard intercommunication in the middle part of the second push away mud chamber have with the third air guide channel 17 that third pushed away mud chamber intercommunication jointly, the outer end surface of the second inner cavity 1b2, the upper surface middle outside of the second mud pushing cavity are communicated with a fourth air guide channel 18 communicated with the third mud pushing cavity, and when the second slider 52 and the third slider 53 move to the second mud pushing cavity and the third mud pushing cavity respectively, the first ring groove 522 is communicated with the third ring groove 532, the second ring groove 521 is communicated with the fourth ring groove 531, the inner upper end of the third inner cavity 1b3, the inner side of the upper surface middle of the third mud pushing cavity is communicated with a fifth air guide channel 202 communicated with the first piston cavity 2b, the outer end surface of the third inner cavity 1b3, the outer side of the upper surface middle outside of the third mud pushing cavity are communicated with a sixth air guide channel 201 communicated with the second piston cavity 2a, and when the third slider 53 moves to the outer end of the third mud pushing cavity, the fifth air guide channel 202 is communicated with the third annular groove 532, and the sixth air guide channel 201 is communicated with the fourth annular groove 531; the two groups of mud pushing plate groups are symmetrically and slidably connected in the middle cavity 12 and each group of mud pushing plate groups comprises a first mud pushing plate 61, a second mud pushing plate 62 positioned above the first mud pushing plate 61 and a third mud pushing plate 63 positioned above the second mud pushing plate 62, and the inner ends of the first sliding block 51, the second sliding block 52 and the third sliding block 53 are fixedly connected with the first mud pushing plate 61, the second mud pushing plate 62 and the third mud pushing plate 63 respectively to drive the mud pushing plate groups to slide in the middle cavity 12.

It is worth mentioning that as shown in fig. 1, the lower surface of the first mud pushing plate 61 contacts with the bottom surface of the middle chamber 12, the upper surface of the first mud pushing plate 61 contacts with the lower surface of the second mud pushing plate 62, and after the first mud pushing plate 61 is completely pushed out, the second mud pushing plate 62 still contacts with the first mud pushing plate 61, the upper surface of the second mud pushing plate 62 contacts with the lower surface of the third mud pushing plate 63, and after the second mud pushing plate 62 is completely pushed out, the third mud pushing plate 63 still contacts with the second mud pushing plate 62, and the upper surface of the third mud pushing plate 63 contacts with the top surface of the middle chamber 12.

It is worth mentioning that, as shown in fig. 6, when the shutter 4 is fully opened, there is a height difference between the lower surface of the shutter 4 and the third mud jacking plate 63.

Preferably, as shown in fig. 4 and 5, the check valve further includes two check valves respectively installed in the fifth air guide channels 202 and configured to stop the flow direction of the third inner chamber 1b3 to the first piston chamber 2b, the check valve includes a valve core 71 and a first return spring 70, through holes communicated with the fifth air guide channels 202 are respectively formed in two side walls of the upper chamber 13, and one end of the valve core 71 away from the first return spring 70 passes through the through holes and extends into the upper chamber 13.

It is worth mentioning that, as shown in fig. 5, one end surface of the valve core 71 extending into the upper chamber 13 is hemispherical.

Preferably, as shown in fig. 1, 3 and 4, the valve body includes an upper valve body 2 and a lower valve body 1, the lower chamber 11, the middle chamber 12 and the upper chamber 13 are opened in the lower valve body 1, and the piston cavity is opened in the upper valve body 2.

Preferably, as shown in fig. 4 and 5, a lifting mud pushing plate 9 is slidably connected in the lower chamber 11, and a plurality of second return springs 91 are fixedly connected between the lifting mud pushing plate 9 and the bottom surface of the lower chamber 11.

It can be understood that, as shown in fig. 1 and 4, when the shutter 4 is closed, the shutter 4 is lowered into the lower chamber 11 and presses the lifting and lowering mud pushing plate 9 to move downward, and when the shutter 4 is opened, the lifting and lowering mud pushing plate 9 moves upward to the opening of the lower chamber 11 under the action of the second return spring 91.

Preferably, as shown in fig. 1, the driving device 8 is a hand wheel, and the upper part of the upper valve body 2 is in threaded connection with the upper part of the valve rod 3.

It will be appreciated that the valve stem 3 is rotatably connected to the shutter 4 as shown in figure 1.

The working principle of the invention is as follows:

when the hand wheel is rotated to open the gate plate 4, the valve rod 3 moves upwards to drive the movable piston 31 and the gate plate 4 to move upwards, when the gate plate 4 starts to move upwards, the acting force of the upper surface of the lifting mud-pushing plate 9 is removed, at this time, under the acting force of the second return spring 91, the lifting mud-pushing plate 9 moves upwards along the lower chamber 11, so that mud on the side wall of the lower chamber 11 is scraped, the movable piston 31 moves upwards to compress the second piston chamber 2a, so that the volume of the first piston chamber 2b is increased, the volume of the second piston chamber 2a is decreased, further, gas in the second piston chamber 2a is gradually pressed into the sixth gas guide channel 201 and enters the first outer chamber 1a1 through the fourth ring groove 531, the fourth gas guide channel 18, the second ring groove 521 and the second gas guide channel 16, so as to push the first slider 51 to move towards the central position of the gate plate 4, further, the first mud-pushing plate 61 is driven to move towards the central position of the gate plate 4, after the first mud pushing plate 61 is completely pushed out, the gas in the second piston chamber 2a enters the second outer chamber 1a2 through the sixth gas guide channel 201, the fourth ring groove 531 and the fourth gas guide channel 18, pushes the second slider 52 to move towards the center of the gate plate 4, and further drives the second mud pushing plate 62 to move towards the center of the gate plate 4, so as to scrape off the slurry on the upper surface of the first mud pushing plate 61 during the moving process, after the second mud pushing plate 62 is completely pushed out, the gas in the second piston chamber 2a enters the third outer chamber 1a3 through the sixth gas guide channel 201, pushes the third slider 53 to move towards the center of the gate plate 4, and further drives the third mud pushing plate 63 to move towards the center of the gate plate 4 until the gate plate 4 is completely opened, so as to scrape off the slurry on the upper surface of the second mud pushing plate 62 during the moving process, at this time, the lower surface of the first mud pushing plate 61 and the upper surface of the third mud pushing plate 63 respectively contact with the bottom surface and the top surface of the middle chamber 12, so that when the gate plate 4 is lifted, slurry medium can be prevented from being retained at the side position of the middle chamber 12, namely in a cavity between the side wall of the middle chamber 12 and the gate plate 4;

when the hand wheel is rotated to close the gate plate 4, the valve rod 3 moves downwards to drive the movable piston 31 and the gate plate 4 to move downwards, when the gate plate 4 contacts the valve core 71 and continues to move downwards, the valve core 71 moves outwards, so that the one-way valve is in an open state, the movable piston 31 moves downwards to compress the first piston chamber 2b, the volume of the second piston chamber 2a is increased, the volume of the first piston chamber 2b is reduced, the gas in the first piston chamber 2b enters the third inner chamber 1b3 through the fifth gas guide channel 202, the third slider 53 is pushed to move in a direction away from the center of the gate plate 4, the third mud pushing plate 63 is driven to retract to the original position, and then the gas in the first piston chamber 2b enters the second inner chamber 1b2 through the fifth gas guide channel 202 and the third gas guide channel 531 to push the second slider 52 to move away from the center of the gate plate 4, and then the second mud pushing plate 62 is driven to retract to the original position, and then the gas in the first piston chamber 2b enters the first inner chamber 1b1 through the fifth gas guide channel 202, the third ring groove 531 and the first ring groove 521 to push the first slider 51 to move in the direction away from the center of the gate plate 4, so as to drive the first mud pushing plate 61 to retract to the original position, at this time, the gate plate 4 continues to move downwards until contacting with the lifting mud pushing plate 9, and continues to move to downwards extrude the lifting mud pushing plate 9, so that the gate plate 4 is completely closed, and therefore, when the gate plate 4 is closed, the gate plate 4 can be prevented from being damaged due to the influence of mud.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A flat gate valve comprises a valve body, a gate plate and a gate plate controller, wherein the valve body is provided with a flow channel which is communicated or separated by the gate plate, a middle cavity communicated with the flow channel is arranged at the position of the gate plate in the valve body, an upper cavity communicated with the middle cavity is arranged above the gate plate in the valve body, a lower cavity communicated with the middle cavity is arranged below the gate plate in the valve body, the gate plate controller is arranged in linkage with the gate plate, the gate plate controller comprises a driving device for lifting the gate plate and a valve rod for connecting the driving device with the gate plate, when the driving device drives the gate plate to enter the upper cavity, the flow channel is in a conducting state, when the driving device drives the gate plate to enter the lower cavity, the flow channel is in a stopping state, and the flat gate valve is characterized in that the flat gate valve further comprises a mud pushing protection mechanism, for scraping off the mud of flashboard side position, push away mud protection mechanism includes:

the valve rod penetrates through the piston cavity, a movable piston which is in sliding connection with the inner wall of the piston cavity is fixedly connected to the valve rod, and the movable piston divides the piston cavity into a first piston cavity and a second piston cavity which is located above the first piston cavity;

two groups of mud pushing cavity groups are symmetrically arranged on two sides of the valve body, which are positioned in the middle cavity, each group of mud pushing cavity group comprises a first mud pushing cavity, a second mud pushing cavity positioned above the first mud pushing cavity and a third mud pushing cavity positioned above the second mud pushing cavity, the first mud pushing cavity, the second mud pushing cavity and the third mud pushing cavity are respectively and slidably connected with a first slide block, a second slide block and a third slide block, the first slide block separates the first mud pushing cavity into a first inner cavity close to one side of the middle cavity and a first outer cavity far away from one side of the middle cavity, the second slide block separates the second mud pushing cavity into a second inner cavity close to one side of the middle cavity and a second outer cavity far away from one side of the middle cavity, and the third slide block separates the third mud pushing cavity into a third inner cavity close to one side of the middle cavity and a third outer cavity far away from one side of the middle cavity, the second slider lateral surface is seted up and is close to the first annular of well cavity one side and is located the second annular in the first annular outside, the third slider lateral surface is seted up and is close to the third annular of well cavity one side and is located the fourth annular in the third annular outside, the inboard upper end of first inner chamber the outside terminal surface of first outer cavity respectively with the second pushes away mud chamber intercommunication and has first air guide channel and second air guide channel, and works as the second slider removes when the second pushes away mud chamber outermost end, first air guide channel with first annular is linked together, second air guide channel with the second annular communicates mutually, the inboard upper end of second inner chamber the upper surface middle part inboard of second push away mud chamber communicate jointly have with the third air guide channel that third pushed away mud chamber intercommunication, the outside terminal surface of second inner chamber, The second pushes away the upper surface middle part outside in mud chamber and communicates together with the third pushes away the fourth air guide passageway in mud chamber intercommunication, and when the second slider, the third slider moves respectively the second pushes away mud chamber, when the third pushes away the outermost end in mud chamber, first annular with the third annular is linked together, the second annular with the fourth annular communicates mutually, the inboard upper end in third inner chamber, the upper surface middle part inboard in third pushes away the mud chamber communicates together with the fifth air guide passageway that communicates with first piston cavity, the outer end face in third inner chamber, the upper surface middle part outside in third pushes away the mud chamber communicates together with the sixth air guide passageway that communicates with second piston cavity, and when the third slider moves the outer end in third pushes away the mud chamber, the fifth air guide passageway with the third annular is linked together, the sixth air guide channel is communicated with the fourth ring groove;

two sets of mud pushing plate groups, symmetrical sliding connection in the middle cavity, every group mud pushing plate group including first mud pushing plate, be located the second mud pushing plate of first mud pushing plate top and be located the third mud pushing plate of second mud pushing plate top, first slider the second slider with the inner of third slider respectively with first mud pushing plate, the second mud pushing plate third mud pushing plate fixed connection is used for driving mud pushing plate group slides in the middle cavity.

2. The plate valve as claimed in claim 1, further comprising two check valves respectively installed in the fifth air guide channels and used for stopping the flow direction of the third inner chamber to the first piston chamber, wherein each check valve comprises a valve core and a first return spring, through holes communicated with the fifth air guide channels are formed in both side walls of the upper chamber, and one end of the valve core, which is far away from the first return spring, penetrates through the through holes and extends into the upper chamber.

3. The gate valve of claim 1, wherein the valve body comprises an upper valve body and a lower valve body, the lower chamber, the middle chamber, the upper chamber opening into the lower valve body, and the piston cavity opening into the upper valve body.

4. The plate valve of claim 1, wherein a lifting mud pushing plate is slidably connected in the lower chamber, and a plurality of second return springs are fixedly connected between the lifting mud pushing plate and the bottom surface of the lower chamber.

5. The flat gate valve of claim 3, wherein said drive means is a hand wheel, and an upper portion of said upper valve body is threadedly connected to an upper portion of said valve stem.