Wellhead electric anti-flow overflow device

Abstract

This invention discloses a wellhead electric overflow prevention device, relating to the field of wellhead blowout prevention technology. It includes a main body with a vertical hole for a drill pipe to pass through and a movable cavity communicating with the vertical hole. Two gates are slidably disposed within the movable cavity. An arc-shaped plate is rotatably disposed on the side of each gate that is close to it. A sealing gasket is slidably disposed inside the arc-shaped plate. The device also includes a triggering mechanism. When the two arc-shaped plates abut against each other and form a ring, the triggering mechanism operates to force the sealing gasket to approach and abut against the drill pipe. This invention provides a wellhead electric overflow prevention device where, when the two gates abut against each other, the two arc-shaped plates also abut against each other to form a ring, allowing the ring structure to rotate between the two gates to accommodate the rotation of the drill pipe. The sealing gasket is slidably disposed within the arc-shaped plate, and the triggering mechanism forces the sealing gasket to approach and abut against the drill pipe, thus minimizing friction and damage between the sealing gasket and the drill pipe.

Description

Technical Field

[0001] This invention relates to the field of wellhead blowout prevention technology, and specifically to an electric wellhead overflow prevention device. Background Technology

[0002] An overflow preventer is a safety device used to prevent blowouts or media leaks, typically installed in the wellhead system. When operating, its actuator holds the drill pipe in place to prevent blowouts, making it an essential piece of equipment used on oil wells.

[0003] For example, the patent document with authorization announcement number CN208267819U, authorization announcement date of April 21, 2018, and titled "A Novel Gate Blowout Preventer" includes a blowout preventer housing, a vertical hole, a stamping chamber, a blowout preventer gate, a flange connector, a flange, and a drive cylinder. The blowout preventer housing is provided with a vertical hole that allows fluid or tubular objects to pass through. A stamping chamber is provided on the outside of the vertical hole and opposite to the vertical hole. A blowout preventer gate is provided on the inside of the stamping chamber.

[0004] In existing technologies, sealing is typically achieved by directly contacting the drill pipe with an arc-shaped gate. Obviously, if the drill pipe is rotating, there will be relative rotation between the arc-shaped gate and the drill pipe, which can damage the drill bit and the gate, and may even affect the sealing effect at the gate, causing overflow. Summary of the Invention

[0005] The purpose of this invention is to provide an electric wellhead overflow prevention device to address the aforementioned shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An electric overflow prevention device for wellheads includes a main body, which has a vertical hole for passing through a drill pipe and a movable cavity communicating with the vertical hole. Two gates are slidably arranged in the movable cavity. An arc-shaped plate is rotatably arranged on the side of the two gates that are close to each other. A sealing gasket is slidably arranged on the inner side of the arc-shaped plate. The device also includes a triggering mechanism. When the two arc-shaped plates abut against each other and form a ring, the triggering mechanism operates to force the sealing gasket to approach and abut against the drill pipe.

[0007] In the above-mentioned wellhead electric anti-overflow device, the sealing gasket is constructed in an arc shape that is adapted to the drill pipe, and a sealing groove is constructed on the arc plate, and the sealing gasket slides in the sealing groove.

[0008] In the aforementioned electric overflow prevention device for wellheads, three sealing gaskets are slidably connected to one of the arc-shaped plates. When two arc-shaped plates abut against each other, the six sealing gaskets approach each other to form a ring to seal the drill pipe and the arc-shaped plates.

[0009] The above-mentioned electric overflow prevention device for wellheads includes a sliding plate on one side of each of the two gates that are close to each other, an arc plate that is rotatably connected to the sliding plate, and a first elastic element for forcing the sliding plate away from the gates; when the two gates are close to each other, the two sliding plates and the two arc plates first abut against each other, and the triggering mechanism is driven by the stroke of the two gates approaching each other after the two sliding plates are connected.

[0010] In the aforementioned electric overflow prevention device for wellheads, the sliding plate is constructed with an arc-shaped groove, and the arc-shaped plate is slidably disposed within the arc-shaped groove.

[0011] The above-mentioned wellhead electric overflow prevention device includes a triggering mechanism comprising a second elastic element for forcing the sealing gasket close to the arc-shaped plate, an arc-shaped abutment plate provided in the arc-shaped groove, the abutment plate being slidably disposed along the thickness direction of the slide plate, a through hole communicating with the sealing groove being constructed on the arc-shaped plate, a movable plate being slidably disposed in the through hole, a first wedge block being constructed on the side of the sealing gasket close to the slide plate, and a first wedge surface being constructed on one end of the movable plate.

[0012] In the aforementioned wellhead electric overflow prevention device, the sliding plate has a through hole communicating with an arc-shaped groove. A trigger plate is slidably disposed in the through hole. A second wedge block is constructed at the end of the trigger plate near the contact plate, and a second wedge surface is constructed on the contact plate. The end of the trigger plate away from the second wedge block protrudes from the sliding plate. When the sliding plate and the gate plate approach each other, the trigger plate is pushed by the gate plate and moves closer to the contact plate, thereby driving the contact plate and the movable plate to approach the sealing gasket, thus forcing the sealing gasket to approach and push against the drill pipe.

[0013] The aforementioned electric overflow prevention device for wellheads also includes a third elastic element for forcing the movable plate close to the contact plate.

[0014] The aforementioned electric overflow prevention device for wellheads also includes a limiting mechanism for forcing the end of the arc-shaped plate to align with the end of the sliding plate.

[0015] The aforementioned electric overflow prevention device for wellheads has a semi-circular rubber pad at the bottom of the sliding plate.

[0016] In the above technical solution, the present invention provides a wellhead electric anti-overflow device in which, when the two gate plates abut and connect, the two arc-shaped plates also abut and connect to form a ring, so that the ring structure can rotate between the two gate plates to adapt to the rotation of the drill pipe; a sealing gasket is slidably set inside the arc plate, and then the sealing gasket is forced to approach and abut the drill pipe based on the triggering mechanism, so as to minimize friction and damage between the sealing gasket and the drill pipe. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1 This is a schematic diagram of the overall structure provided for an embodiment of the present invention; Figure 2 This is a schematic diagram of a sealing gasket structure provided in another embodiment of the present invention; Figure 3 This is a schematic diagram of a skateboard structure provided in another embodiment of the present invention; Figure 4 This is a schematic diagram of the first elastic element structure provided in another embodiment of the present invention; Figure 5 This is a schematic diagram of the second elastic element structure provided in another embodiment of the present invention; Figure 6 This is a schematic diagram of a trigger plate structure provided in another embodiment of the present invention; Figure 7 This is a schematic diagram of the third elastic element structure provided in another embodiment of the present invention; Figure 8 This is a schematic diagram of a movable plate structure provided in another embodiment of the present invention; Figure 9 This is a schematic diagram of a semi-annular rubber pad structure provided in another embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Main body; 2. Drill rod; 3. Gate plate; 4. Arc plate; 5. Sealing gasket; 6. Sealing strip; 7. Linear drive mechanism; 8. Slide plate; 9. First elastic element; 10. Second elastic element; 11. Contact plate; 12. Movable plate; 13. First wedge block; 14. First wedge surface; 15. Trigger plate; 16. Second wedge block; 17. Second wedge surface; 18. Slide rod; 19. Third elastic element; 20. Semi-annular rubber pad. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Reference Figure 1-9This invention provides a wellhead electric overflow prevention device, including a main body 1. The main body 1 has a vertical hole for passing through a drill pipe 2 and a movable cavity communicating with the vertical hole. Two gate plates 3 are slidably arranged in the movable cavity. An arc plate 4 is rotatably arranged on the side of the two gate plates 3 that are close to each other. A sealing gasket 5 is slidably arranged on the inner side of the arc plate 4. The device also includes a triggering mechanism. When the two arc plates 4 abut against each other and form a ring, the triggering mechanism operates to force the sealing gasket 5 to approach and abut against the drill pipe 2.

[0022] Specifically, the upper and lower sides of the main body 1 are equipped with flange structures for easy connection with other mechanisms at the wellhead; the left and right sides of the main body 1 are equipped with linear drive mechanisms 7 for driving the gate to slide within the movable cavity. The linear drive mechanism 7 is electrically driven, such as a combination of a motor and a reduction mechanism, or a combination of a motor and a lead screw structure. Compared with hydraulic drive, the electric anti-overflow device has a simple structure, eliminates the need for hydraulic pipelines, and avoids the risk of pipeline leakage; a dynamic sealing structure is provided between the gate 3 and the movable cavity, such as several sealing strips 6 embedded in the outer wall of the gate 3; the above are all existing technologies and will not be elaborated here. The innovation of this invention lies in the fact that each of the two gate plates 3 is provided with an arc-shaped plate 4, a sealing gasket 5, and a triggering mechanism on the side where they are close to each other. For a gate plate 3, the arc-shaped plate 4 is rotatably connected to it, allowing the arc-shaped plate 4 to rotate 180 degrees and detach from the gate plate 3. However, when the two gate plates 3 are close to each other, the two arc-shaped plates 4 can abut and form a ring, allowing the two arc-shaped plates 4 to rotate continuously between the two gate plates 3, thus accommodating the rotation of the drill rod 2. The sealing gasket 5 is located on the side of the arc-shaped plate 4 closest to the drill rod 2. When the two arc-shaped plates 4 are abutting, the sealing gasket 5 is on the side closest to the arc-shaped plate 4. The triggering mechanism can be an electric push rod or similar structure. After the two arc-shaped plates 4 are abutted, the triggering mechanism operates to force the sealing gasket 5 close to the drill rod 2, so that the multiple sealing gaskets 5 on the two arc-shaped plates 4 abut against the drill rod 2 and form a ring-shaped sealing ring, thus sealing the drill rod 2 and the arc-shaped plates 4.

[0023] The advantage of this design is that, in existing technologies, the sealing gasket 5 is generally made of rubber, and rubber structures typically deform under pressure, improving connectivity and sealing performance. That is, the inner diameter of the annular sealing ring formed by multiple sealing gaskets 5 is generally smaller than the outer diameter of the drill rod 2. When the sealing gasket 5 contacts the drill rod 2, its deformation due to contact improves the seal between them. Obviously, if the sealing gasket 5 is directly fixed to the arc plate 4, a situation arises where the two arc plates 4 are not aligned while the sealing gasket 5 is already in contact with the drill rod 2. This would cause friction and damage between the drill rod 2 and the sealing gasket 5, and could even cause misalignment between the arc plate 4 and the gate plate 3, affecting their alignment. Therefore, a triggering mechanism is provided to force the sealing gasket 5 closer to the drill rod 2 after the two arc plates 4 are aligned. The friction between the sealing gasket 5 and the drill rod 2 at this point directly drives the two arc plates 4 to rotate between the two gate plates 3, minimizing damage to the drill rod 2 and the actuators of the overflow prevention device.

[0024] In another embodiment of the present invention, the sealing gasket 5 is further configured as an arc shape adapted to the drill pipe 2, and a sealing groove is constructed on the arc plate 4, within which the sealing gasket 5 slides. Three sealing gaskets 5 are slidably connected to one of the arc plates 4. When two arc plates 4 abut against each other, the six sealing gaskets 5 approach each other to form a ring to seal the drill pipe 2 and the arc plate 4. Specifically, the sealing groove has an overall arc-shaped structure, and the sealing gasket 5 is shaped to fit the sealing gasket 5, allowing it to slide radially along the arc plate 4 within the sealing groove. The arc plate 4 is semi-circular, and the three sealing gaskets 5 on one arc plate 4 can also form a semi-circle when they approach each other. In this case, the semi-circular ring of the arc plate 4 and the semi-circular ring formed by the three sealing gaskets 5 are concentric. When two arc plates 4 are joined, the six sealing gaskets 5 can form a ring-shaped sealing ring that abuts against the drill rod 2 to achieve a seal. Simultaneously, this sealing ring also seals the sealing groove, minimizing overflow at the arc plate 4. The advantage is that multiple sealing gaskets 5 can slide radially along the arc plate 4 within their corresponding sealing grooves, thereby abutting against the drill rod 2 to accommodate its rotation, or retracting into the sealing groove to avoid premature contact with the drill rod 2 and affecting the joining of the arc plate 4.

[0025] In another embodiment of the present invention, preferably, a sliding plate 8 is slidably provided on the side of the two gate plates 3 that are close to each other, and an arc plate 4 is rotatably connected to the sliding plate 8. The invention also includes a first elastic member 9 for forcing the sliding plate 8 away from the gate plate 3. When the two gate plates 3 are close to each other, the two sliding plates 8 and the two arc plates 4 first abut and connect, and the triggering mechanism is driven by the stroke of the two gate plates 3 approaching each other after the two sliding plates 8 connect. Specifically, in the above embodiment, the arc plate 4 can be directly rotatably connected to the gate plate 3. In this embodiment, the arc plate 4 is rotatably connected to the slide plate 8 on the gate plate 3. The sliding direction of the slide plate 8 on the gate plate 3 is parallel to the sliding direction of the gate plate 3 in the movable cavity. The gate plate 3 is constructed with a sliding groove, and the slide plate 8 is slidably disposed in the sliding groove. The slide plate 8 has a certain sliding stroke in the sliding groove. The first elastic member 9 can be a spring structure in the prior art. One end of the spring is fixed to the inner wall of the sliding groove, and the other end is fixed to the slide plate 8. The first elastic member 9 forces the slide plate 8 to move to the end of the sliding groove closer to the drill rod 2, so that the ends of the slide plate 8 and the arc plate 4 can protrude from the gate plate 3 (e.g., Figure 3 and Figure 4 (As shown); the purpose of this arrangement is that when the two gate plates 3 approach each other, the ends of the two arc plates 4 can first abut and connect, and then the two gate plates 3 continue to approach, thereby overcoming the elastic force of the first elastic element 9, so that the slide plate 8 is relatively retracted into the slide groove, so that the arc plate 4, the slide plate 8 and the gate plate 3 are aligned; the advantage is that this connection method can leave a section of the gate plate 3's travel stroke after the two arc plates 4 abut and connect, and this travel stroke can be used to drive the trigger mechanism to run (the trigger mechanism can be a linkage or other travel ring structure in the prior art, to drive the trigger mechanism to run based on the travel stroke of the gate plate 3), so that after the two arc plates 4 connect, multiple sealing gaskets 5 are forced to approach the drill rod 2.

[0026] Preferably, the slide plate 8 has an arc-shaped groove, and the arc-shaped plate 4 is slidably disposed within the arc-shaped groove. Specifically, the side of the slide plate 8 closest to the arc-shaped plate 4 is constructed to fit the arc shape, and the arc-shaped groove is constructed on the side of the slide plate 8 closest to the arc-shaped plate 4 so that the arc-shaped plate 4 can slide (or rotate) within the arc-shaped groove until the two arc-shaped plates 4 are joined together, and the arc-shaped grooves in the two arc-shaped plates 4 form an annular groove, so that the annular structure formed after the two arc-shaped plates 4 are joined together can slide (or rotate) within the annular groove.

[0027] Furthermore, the triggering mechanism includes a second elastic element 10 for forcing the sealing gasket 5 close to the arc plate 4. An arc-shaped abutment plate 11 is provided in the arc groove. The abutment plate 11 is slidably disposed along the thickness direction of the slide plate 8. A through hole communicating with the sealing groove is constructed on the arc plate 4. A movable plate 12 is slidably disposed in the through hole. A first wedge block 13 is constructed on the side of the sealing gasket 5 close to the slide plate 8. A first wedge surface 14 is constructed on one end of the movable plate 12. The slide plate 8 has a through hole communicating with the arc-shaped groove. A trigger plate 15 is slidably disposed in the through hole. A second wedge block 16 is constructed on the end of the trigger plate 15 near the abutment plate 11. A second wedge surface 17 is constructed on the abutment plate 11. The end of the trigger plate 15 away from the second wedge block 16 protrudes from the slide plate 8. When the slide plate 8 and the gate plate 3 approach each other, the trigger plate 15 is abutted by the gate plate 3 and approaches the abutment plate 11, so as to drive the abutment plate 11 and the movable plate 12 to approach the sealing gasket 5, thereby forcing the sealing gasket 5 to approach and abut the drill rod 2.

[0028] Specifically, the sealing gasket 5 includes an elastic sealing portion that abuts against the drill pipe 2 and a rigid portion that slides in connection with the sealing groove (a sealing strip 6 can be embedded in the outer wall of the rigid portion to improve the sealing performance between the sealing gasket 5 and the sealing groove). The second elastic element 10 can be a spring from the prior art, with one end fixed to the inner wall of the sealing groove and the other end fixed to the rigid portion of the sealing gasket 5, thereby forcing the sealing gasket 5 to retract into the sealing groove (e.g., Figure 4 (As shown); the first wedge block 13 is constructed on the rigid part of the sealing gasket 5. The first wedge surface 14 at one end of the movable plate 12 is adapted to the first wedge block 13, so that when the movable plate 12 approaches the sealing gasket 5 along the through hole, it can force the sealing gasket 5 away from the arc plate 4; the abutment plate 11 is constructed as an arc shape adapted to the arc groove. A slide rod 18 is constructed on the abutment plate 11, and a groove adapted to the slide rod 18 is constructed on the slide plate 8, so that the abutment plate 11 can slide in the arc groove along the thickness direction of the slide plate 8; when the arc plate 4 rotates in the arc groove, the sealing gasket 5 and the movable plate 12 rotate with the arc plate 4, while the abutment plate 11 does not rotate in the arc groove. Therefore, friction will occur between the movable plate 12 and the abutment plate 11 (compared to the friction between the sealing gasket 5 and the drill rod 2). (In terms of friction, this friction method is more acceptable and controllable). The length direction of the trigger plate 15 is set along the sliding direction of the slide plate 8. The overall structure of the abutment plate 11 is a semi-circular ring. The second wedge surface 17 is constructed at the junction of its top surface and the outer side wall. The second wedge surface 17 is adapted to the second wedge block 16. Since the end of the trigger plate 15 away from the abutment plate 11 is exposed on the slide plate 8, the slide plate 8 and the gate plate 3 can abut the trigger plate 15 when they approach each other, so as to force the trigger plate 15 to retract into the through hole. Then, the second wedge block 16 abuts the second wedge surface 17, thereby forcing the abutment plate 11 to approach the movable plate 12, so as to drive the movable plate 12 to approach the sealing gasket 5. And through the first wedge surface 14 and the first wedge block 13, the sealing gasket 5 is forced to approach and abut the drill rod 2.

[0029] The advantage of this arrangement is that, during the process of the two gate plates 3 approaching each other, the two sliding plates 8 and the two curved plates 4 can first engage in contact, and the two contact plates 11 can also engage in contact, allowing the two curved plates 4 to rotate (or slide) between the two sliding plates 8. Subsequently, as the two gate plates 3 continue to approach, they can force the sliding plates 8 into their corresponding grooves, so that they can contact the trigger plate 15 through the outer wall of the gate plate 3. Until the gate plate 3 and the sliding plates 8 are in contact, the trigger plate 15 is retracted into the through hole, so that the sealing gasket 5 is forced to approach and contact the drill rod 2 through the contact plate 11 and the movable plate 12, etc.; when the sealing gasket 5 approaches and contacts the drill rod 2... During the contact process of drill rod 2, if drill rod 2 is rotating, drill rod 2 can drive the sealing gasket 5 and arc plate 4 to rotate through friction, so that the annular structure formed by the two abutment plates 11 rubs against the multiple movable plates 12, so as to avoid friction and damage between the sealing gasket 5 and drill rod 2 as much as possible; conversely, when the two gate plates 3 are far apart, the elastic force of the second elastic element 10 can force the sealing gasket 5, movable plate 12, abutment plate 11 and trigger plate 15 to reset (in this embodiment, the first wedge surface 14 and the first wedge block 13 remain in contact, and the second wedge surface 17 and the second wedge block 16 remain in contact).

[0030] In the above embodiment, the friction between the sealing gasket 5 and the drill rod 2 is transferred to the movable plate 12 and the abutment plate 11. Compared to the flexible material of the sealing gasket 5, the friction between the rigid movable plate 12 and the abutment plate 11 causes less damage, but prolonged use will still cause wear, which will affect the abutment force of the sealing gasket 5 against the drill rod 2 (if the movable plate 12 shortens due to friction, the sealing gasket 5 will slightly retract into the sealing groove, which will affect the displacement and abutment force of the sealing gasket 5), thereby affecting the sealing effect. Preferably, a third elastic member 19 is also included to force the movable plate 12 closer to the abutment plate 11. Specifically, the third elastic element 19 is disposed on one side of the movable plate 12 and the sealing gasket 5 (the second elastic element 10 is disposed on the other side of the sealing gasket 5 to minimize interference between the two). The third elastic element 19 can be a spring structure in the prior art, with one end fixed to the movable plate 12 and the other end fixed to the arc plate 4, thereby forcing the movable plate 12 closer to the contact plate 11 through the third elastic element 19. In this embodiment, when the trigger plate 15 is inserted into the through hole, the second wedge block 16 and the second wedge surface 17 remain in contact, while the first wedge block 13 separates from the first wedge surface 14, so that the side wall of the movable plate 12 contacts the end of the first wedge block 13. In this way, the position of the sealing gasket 5 can be limited by the movable plate 12 until the two gates 3 move away from each other. The movable plate 12 can then move towards the contact plate 11 under the action of the third elastic element 19, thereby driving the contact plate 11 and the trigger plate 15 to reset. Subsequently, the second elastic element 10 can drive the sealing gasket 5 to reset. The advantage of this arrangement is that, in this embodiment, the side wall of the movable plate 12 abuts against and limits the end of the first wedge block 13. When the movable plate 12 has a certain wear space, that is, when the movable plate 12 becomes shorter due to friction, the movable plate 12 will move slightly upward compared to the original. However, this does not affect the movable plate 12 from continuing to abut against the end of the first wedge block 13 through the side wall, and does not affect the contact force and sealing effect of the sealing gasket 5 on the drill rod 2. Until the wear of the movable plate 12 exceeds a certain length, the movable plate 12 will no longer be able to abut against the first wedge block 13 through the side wall, and the contact force of the sealing gasket 5 on the drill rod 2 will decrease. At this time, the component needs to be inspected or replaced in time (the device is generally inspected regularly, and the movable plate 12 can be directly replaced when the wear reaches a certain level, which will not be elaborated).

[0031] In the above embodiments, when the two arc-shaped plates 4 rotate between the two sliding plates 8, the relative positions between the arc-shaped plates 4 and the sliding plates 8 will change. Therefore, there will be a situation where one arc-shaped plate 4 is simultaneously in both sliding plates 8. Obviously, this will affect the separation of the two gate plates 3. Therefore, when it is necessary to separate the two gate plates 3, the drill rod 2 is actively rotated at a certain angle (the drill rod 2 has its own driving mechanism, and it can also be driven to rotate by other external forces, which is the prior art and will not be described in detail), so that the two arc-shaped plates 4 move into the arc-shaped grooves of the two sliding plates 8 respectively (so that the ends of the arc-shaped plates 4 and the sliding plates 8 are aligned), so that the two gate plates 3 can be separated. In this process, whether the two arc-shaped plates 4 have moved into the corresponding arc-shaped grooves can be determined by a structure such as a position sensor (the structure such as a position sensor that can determine the position of the arc-shaped plate 4 in the arc-shaped groove is the prior art and will not be described in detail or illustrated). After the position of the arc-shaped plates 4 is determined, the two gate plates 3 can be driven to move away from each other.

[0032] In another embodiment of the present invention, a limiting mechanism is further included to force the end of the arc-shaped plate 4 to align with the end of the slide plate 8. Specifically, to prevent the arc-shaped plate 4 from shifting position within the arc-shaped groove when the device is idle, a limiting mechanism is provided on the slide plate 8. The limiting mechanism can be an electric snap-fit ​​mechanism from the prior art to snap the relative positions of the arc-shaped plate 4 and the slide plate 8 when their ends are aligned. Preferably, the limiting mechanism uses a magnetic adsorption structure, in which mutually adsorbing magnets are embedded at positions where the arc-shaped plate 4 and the slide plate 8 are close to each other. When the ends of the arc-shaped plate 4 and the slide plate 8 are aligned, the two magnets adsorb each other to force the ends of the arc-shaped plate 4 and the slide plate 8 to align (the force of the mutual adsorption of the magnets does not affect the operation of the above structure). Correspondingly, the arc-shaped plate 4 and the slide plate 8 as a whole can be made of an alloy structure to minimize the impact on the operation of the magnetic adsorption structure. The magnetic adsorption structure is prior art and will not be described in detail here, nor is it illustrated.

[0033] In various embodiments of the present invention, sealing strips 6 or other sealing structures can be added between the relatively moving structures. For example, a sealing strip 6 is embedded on the outer wall of the gate 3 to accommodate sliding with the movable cavity. A sealing strip 6 is also embedded on the side of the gate 3 near the sliding plate 8 to improve the sealing effect when the gate 3 and the sliding plate 8 are in contact. A dynamic sealing structure, such as a labyrinth sealing structure, can be provided between the arc plate 4 and the sliding plate 8. That is, a small-diameter semi-circular labyrinth structure is provided on the arc plate 4, and a large-diameter semi-circular labyrinth structure is provided on the sliding plate 8. When the two sliding plates 8 and the two arc plates 4 abut and connect, the two small straight... Two semi-circular labyrinth structures of different diameters can be joined to form a small-diameter circular labyrinth structure, and two large-diameter semi-circular labyrinth structures can be joined to form a large-diameter circular labyrinth structure. The two can be matched to each other to complete the dynamic seal between the arc plate 4 and the slide plate 8. The labyrinth sealing structure is an existing technology. This technical solution can be completed by symmetrically dividing a complete circular labyrinth sealing structure into two halves. It will not be described in detail here and is not illustrated. For the parts that need to be in contact, the sealing effect can also be improved by embedding sealing strips 6, such as the ends of the arc plate 4, the slide plate 8, and the gate 3. It will not be described in detail here.

[0034] Preferably, a semi-annular rubber pad 20 is provided at the bottom of the slide plate 8. The larger diameter side of the semi-annular rubber pad 20 is fixed to the slide plate 8, and the smaller diameter side extends to the arc plate 4. When the two slide plates 8 and the two arc plates 4 are connected, the two semi-annular rubber pads 20 are also connected to form an annular rubber pad. This arrangement can minimize the impact of the semi-annular rubber pad 20 on the rotation of the arc plate 4 on the slide plate 8. In the event of a blowout, the greater pressure below can force the annular rubber pad to press against the arc plate 4, thereby creating a dynamic seal between the arc plate 4 and the slide plate 8. At this time, if the drill rod 2 rotates, it will drive the arc plate 4 to rotate, and friction will occur between the arc plate 4 and the annular rubber pad. This does not affect the normal operation of the device, and the annular rubber pad can be inspected or replaced periodically.

[0035] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A wellhead electric overflow prevention device, comprising a main body, wherein the main body has a vertical hole for passing through a drill pipe and a movable cavity communicating with the vertical hole, and two gates are slidably disposed within the movable cavity, characterized in that, An arc-shaped plate is rotatably provided on one side of the two gates that are close to each other, and a sealing gasket is slidably provided on the inner side of the arc-shaped plate. It also includes a triggering mechanism. When the two arc-shaped plates abut against each other and form a ring, the triggering mechanism operates to force the sealing gasket to approach and abut against the drill rod.

2. The wellhead electric overflow prevention device according to claim 1, characterized in that, The sealing gasket is constructed in an arc shape that fits the drill pipe, and a sealing groove is constructed on the arc plate, in which the sealing gasket slides in a sealing groove.

3. The wellhead electric overflow prevention device according to claim 2, characterized in that, Three sealing gaskets are slidably connected to one of the arc-shaped plates. When two arc-shaped plates abut against each other, the six sealing gaskets come closer together to form a ring to seal the drill rod and the arc-shaped plate.

4. The wellhead electric overflow prevention device according to claim 2, characterized in that, Each of the two gates has a sliding plate slidably disposed on one side of each other, and an arc plate is rotatably connected to the sliding plate. The gate also includes a first elastic element for forcing the sliding plate away from the gate. When the two gates approach each other, the two sliding plates and the two arc plates first abut and engage. The triggering mechanism is driven by the stroke of the two gates approaching each other after the two sliding plates engage.

5. A wellhead electric overflow prevention device according to claim 4, characterized in that, The slide plate has an arc-shaped groove, and the arc-shaped plate is slidably disposed in the arc-shaped groove.

6. A wellhead electric overflow prevention device according to claim 5, characterized in that, The triggering mechanism includes a second elastic element for forcing the sealing gasket close to the arc-shaped plate. An arc-shaped abutment plate is provided in the arc-shaped groove. The abutment plate is slidably disposed along the thickness direction of the slide plate. A through hole communicating with the sealing groove is constructed on the arc-shaped plate. A movable plate is slidably disposed in the through hole. A first wedge block is constructed on the side of the sealing gasket close to the slide plate. A first wedge surface is constructed on one end of the movable plate.

7. A wellhead electric overflow prevention device according to claim 6, characterized in that, The slide plate has a through hole communicating with the arc-shaped groove. A trigger plate is slidably disposed in the through hole. A second wedge block is constructed at the end of the trigger plate near the abutment plate. A second wedge surface is constructed on the abutment plate. The end of the trigger plate away from the second wedge block protrudes from the slide plate. When the slide plate and the gate plate approach each other, the trigger plate is abutted by the gate plate and approaches the abutment plate, thereby driving the abutment plate and the movable plate to approach the sealing gasket, thereby forcing the sealing gasket to approach and abut the drill rod.

8. A wellhead electric overflow prevention device according to claim 7, characterized in that, It also includes a third elastic element for forcing the movable plate closer to the abutment plate.

9. A wellhead electric overflow prevention device according to claim 4, characterized in that, It also includes a limiting mechanism for aligning the curved plate end with the sliding plate end.

10. A wellhead electric overflow prevention device according to claim 4, characterized in that, A semi-circular rubber pad is provided at the bottom of the skateboard.

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