Underwater hydraulic control gate valve of Christmas tree for oil exploitation

Abstract

The utility model relates to the technical field of hydraulic control gate valves, in particular to an underwater hydraulic control gate valve of a Christmas tree for oil exploitation. Comprising a shell, one side of the shell communicates with a first pipe, the other side of the shell communicates with a second pipe, the side, away from the first pipe and the second pipe, of the shell is fixedly connected with a hydraulic rod, the telescopic end of the hydraulic rod is located in the shell and fixedly connected with a connecting plate, and the side, away from the hydraulic rod, of the connecting plate is fixedly connected with sliding rods distributed in a central symmetry mode; the side, away from the connecting plate, of the sliding rod is fixedly connected with a first sliding plate, a sliding block is slidably connected into the shell and provided with first cavities distributed in a central symmetry mode, the first sliding plate is slidably connected with the adjacent first cavities, and the sliding block is provided with second cavities distributed in a central symmetry mode. The sealing plate does not make contact with the shell, the first pipe and the second pipe in the moving process along with the sliding block, so that abrasion of the sealing plate is reduced, the sealing effect of the device is guaranteed, and the service life of the device is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulically controlled gate valves, in particular to an underwater hydraulically controlled gate valve for a Christmas tree used in petroleum mining. Background Art

[0002] During offshore oil exploitation, after the oil is extracted, it enters the oil pipeline through the oil tree and is distributed to various refineries. When the oil is transported through the pipeline, a gate valve is needed. The pipeline gate valve is a gate plate of an opening and closing component. The movement direction of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. When the existing gate valve is in use, a seal is formed between the gate plate and the valve body. However, during the process of opening and closing the gate plate, the gate plate and the valve body rub against each other. As the number of opening and closing times increases during use, the sealing material between the gate plate and the valve body will wear, thereby reducing the sealing effect of the gate valve. If the gate valve is not closed tightly, it will affect the transportation of oil and cause economic losses. Utility Model Content

[0003] In order to overcome the shortcomings mentioned in the above background technology, the present invention provides a subsea hydraulically controlled gate valve for oil production using a Christmas tree.

[0004] The technical implementation scheme of the present invention is: an underwater hydraulically controlled gate valve for oil production using a Christmas tree, comprising a shell, one side of the shell is connected to a No. 1 pipe, the other side of the shell is connected to a No. 2 pipe, a hydraulic rod is fixedly connected to the side of the shell away from the No. 1 pipe and the No. 2 pipe, the telescopic end of the hydraulic rod is located in the shell and fixedly connected to a connecting plate, the side of the connecting plate away from the hydraulic rod is fixedly connected to a sliding rod with central symmetry distribution, the side of the sliding rod away from the connecting plate is fixedly connected to a first sliding plate, a sliding block is slidably connected in the shell, the sliding block is provided with a first cavity with central symmetry distribution, the first sliding plate is located in an adjacent first cavity and slides, the sliding block is provided with a second cavity with central symmetry distribution, a sealing plate is slidably connected in the second cavity, the first cavity is located adjacent to the first sliding plate and away from the adjacent sliding rod, the first cavity is filled with liquid, the second cavity and the sealing space formed by the adjacent sealing plate are filled with liquid, the part of the second cavity filled with liquid is connected to the part of the adjacent first cavity filled with liquid, the No. 1 pipe and the No. 2 pipe are respectively pressed and matched with the adjacent sealing plates.

[0005] Preferably, the back sides of the sealing plates that are symmetrically distributed at the center are all made of elastic material to form a seal.

[0006] Preferably, the lower side of the sliding block is squeezed into the lower side of the shell, the part where the sliding block fits into the shell is made of elastic material, and the curvature of the lower side of the longitudinal section of the sliding block is greater than that of the lower side of the longitudinal section of the shell.

[0007] Preferably, the sliding block is slidably connected to a first limiting column that is centrally symmetrically distributed, a spring is arranged between the sliding block and a side of the first limiting column away from the adjacent sealing plate, and the sealing plate is provided with a groove that cooperates with the adjacent first limiting column.

[0008] Preferably, the shell is slidably connected with a second limiting column, a spring is provided between the second limiting column and the shell, and the sliding block is provided with a groove which cooperates with the second limiting column in limiting manner.

[0009] Preferably, it also includes a connecting tube, which is slidably connected to the side of the No. 2 pipe close to the shell, the No. 2 pipe is fixedly connected to a fixed shell, a sliding column is slidably connected to the fixed shell, the No. 2 pipe is provided with a slide groove, the fixed shell is connected to the No. 2 pipe through the slide groove, the sliding column is slidably matched with the slide groove of the No. 2 pipe, the sliding column is fixedly connected to the side of the connecting tube away from the shell, and the connecting tube is in contact with the No. 1 pipe.

[0010] Preferably, the chute of the No. 2 pipe is located on the upper side of the No. 2 pipe, and is used to discharge the liquid entering the chute of the No. 2 pipe.

[0011] Preferably, a groove is provided on one side of the No. 1 pipe close to the shell, the inner side of the groove of the No. 1 pipe is made of elastic material, and the groove of the No. 1 pipe includes three diameters, large, medium and small. The large diameter is larger than the outer diameter of the connecting tube, the medium diameter is smaller than the outer diameter of the connecting tube but larger than its inner diameter, and the small diameter is equal to the inner diameter of the connecting tube.

[0012] Preferably, the curved portion of the longitudinal section of the connecting tube close to the sliding column is streamlined, a diameter change is provided inside the No. 2 pipe, and the longitudinal section curve of the diameter change inside the No. 2 pipe is streamlined to reduce the resistance to liquid flow.

[0013] Preferably, a second sliding plate is slidably connected to a side of the shell away from the sliding block, the second sliding plate is squeezed and matched with the connecting plate, a spring is arranged between the second sliding plate and a side of the shell away from the sliding block, symmetrically distributed limit blocks are fixedly connected to the shell, the symmetrically distributed limit blocks are all limitedly matched with the second sliding plate, the second sliding plate is slidably connected to the telescopic end of the hydraulic rod, liquid is injected between a side of the second sliding plate away from the symmetrically distributed limit blocks and the shell, liquid is injected between a side of the sliding column away from the shell and the fixed shell, and a portion of the fixed shell injected with liquid and a portion of the shell injected with liquid are connected through a pipeline.

[0014] The present invention has the following advantages: the present invention reduces the wear of the sealing plate by preventing the sealing plate from contacting the shell, the first pipe and the second pipe during the movement of the sliding block, thereby ensuring the sealing effect of the device and extending the service life of the device.

[0015] By first squeezing the sliding block against the middle of the lower side of the shell, the residual liquid in the shell is discharged, thereby preventing the liquid such as petroleum in the shell from being solidified for a long time and causing the pipeline to be blocked.

[0016] When the gate is opened, the No. 1 pipe and the No. 2 pipe are connected through the connecting tube, thereby preventing the turbulence of the liquid through the shell from causing the vibration of the device, thereby extending the service life of the device.

[0017] When the connecting tube is inserted into the groove of the No. 1 pipe, the connecting tube squeezes the elastic part of the groove of the No. 1 pipe, thereby enhancing the sealing effect between the two, and the inner diameters of the connecting tube and the No. 1 pipe are equal, so that the liquid flows more stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0019] Figure 2 It is a sectional view of the three-dimensional structure of the present invention;

[0020] Figure 3 It is a three-dimensional structural cross-sectional view of the sliding block of the present invention;

[0021] Figure 4 It is a planar structural cross-sectional view of the present invention when the housing and the lower side of the sliding block are separated;

[0022] Figure 5 A three-dimensional structural cross-sectional view of the first cavity and the second cavity of the present invention;

[0023] Figure 6 for Figure 3 The enlarged view of point A in the middle;

[0024] Figure 7 for Figure 3 The enlarged view of point B in the middle;

[0025] Figure 8 It is a three-dimensional structural cross-sectional view of the second pipe and the connecting tube of the present invention;

[0026] Fig. 9 It is a three-dimensional structural cross-sectional view of the second sliding plate and the limiting block of the present invention.

[0027] The markings of the components in the accompanying drawings are as follows: 1: shell, 2: pipe No. 1, 3: pipe No. 2, 4: hydraulic rod, 5: connecting plate, 6: sliding rod, 7: first sliding plate, 8: sliding block, 801: first cavity, 802: second cavity, 9: sealing plate, 10: first limiting column, 11: second limiting column, 12: connecting tube, 13: fixed shell, 14: sliding column, 15: second sliding plate, 16: limiting block. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It is hereby stated that the directional terms such as upper, lower, left, right, inside, outside, etc. that appear or will appear in the text of the present invention are only based on the accompanying drawings of the present invention, and are not specific limitations of the present invention.

[0029] Embodiment 1: A submerged hydraulically controlled gate valve for oil production using a Christmas tree, such as Figure 1-Figure 5 and Figure 7As shown, it includes a shell 1, which is arc-shaped all around. The left side of the shell 1 is connected to a No. 1 pipe 2, and the right side of the shell 1 is connected to a No. 2 pipe 3. A hydraulic rod 4 is fixedly connected to the upper side of the shell 1, and the hydraulic rod 4 penetrates the upper side of the shell 1. The telescopic end of the hydraulic rod 4 is located in the shell 1 and is fixedly connected to a connecting plate 5. Two sliding rods 6 distributed symmetrically in the center are fixedly connected to the lower side of the connecting plate 5. A first sliding plate 7 is fixedly connected to the lower side of the sliding rod 6. A sliding block 8 is slidably connected in the shell 1. The lower side of the sliding block 8 is pressed and matched with the lower side of the shell 1. The sliding block 8 moves downward and presses the lower side of the shell 1, thereby discharging the residual oil in the shell 1. The part of the sliding block 8 that matches the shell 1 is an elastic material, which is used to form a seal with the shell 1. The curvature of the curve on the lower side of the longitudinal section of the sliding block 8 is greater than the curvature of the curve on the lower side of the longitudinal section of the shell 1, so that the lower side of the sliding block 8 first contacts with the middle part of the lower side of the shell 1, thereby discharging the oil in the shell 1. The sliding block 8 is provided with two first air holes distributed symmetrically in the center. Cavity 801, the first sliding plate 7 slides in the adjacent first cavity 801, the sliding block 8 is provided with two second cavities 802 distributed symmetrically by the center, the second cavity 802 is slidably connected with a sealing plate 9, the two sealing plates 9 are respectively squeezed and matched with the No. 1 pipe 2 and the No. 2 pipe 3, the first cavity 801 located at the lower side of the adjacent first sliding plate 7 is filled with liquid, the liquid used for transmission mentioned here and below is hydraulic oil (excluding the liquid flowing through the device when the device is in use), the sealed space formed by the second cavity 802 and the adjacent sealing plate 9 is filled with liquid, the sliding block 8 is provided with two through holes distributed symmetrically by the center, the through holes connect the part of the adjacent first cavity 801 filled with liquid and the part of the adjacent second cavity 802 filled with liquid, the back sides of the two sealing plates 9 are elastic materials for forming a seal, when the sealing plate 9 is squeezed with the No. 1 pipe 2 or the No. 2 pipe 3, the elastic part of the sealing plate 9 is deformed to adapt to the shape of the No. 1 pipe 2 or the No. 2 pipe 3, thereby enhancing the sealing effect.

[0030] like Figure 6 As shown, the sliding block 8 is slidably connected to two first limiting columns 10 which are centrally symmetrically distributed. The first limiting columns 10 are composed of a cylinder and a hemisphere. A spring is arranged between the upper side of the first limiting columns 10 and the sliding block 8. The spring is used to insert the adjacent first limiting columns 10 into the grooves of the adjacent sealing plates 9. The sealing plates 9 are provided with grooves which cooperate with the adjacent first limiting columns 10. When the first limiting columns 10 are inserted into the grooves of the adjacent sealing plates 9, the force required to move the sealing plates 9 becomes larger.

[0031] like Figure 3As shown, a second limiting column 11 is slidably connected to the left side of the shell 1. The second limiting column 11 consists of a cylinder and a hemisphere. A spring is arranged between the second limiting column 11 and the shell 1. The spring is used to insert the second limiting column 11 into the groove of the sliding block 8. The sliding block 8 is provided with a groove that cooperates with the second limiting column 11. When the second limiting column 11 is inserted into the groove of the sliding block 8, the force required to move the sliding block 8 becomes larger.

[0032] When using the device, first install the device on the oil tree, with the No. 1 pipe 2 as the inlet and the No. 2 pipe 3 as the outlet. Then the connection and closing of the pipeline can be controlled by the device. When the gate is opened, the hydraulic rod 4 is controlled to contract, and the telescopic end of the hydraulic rod 4 drives the connecting plate 5 to move upward, and the connecting plate 5 drives the two sliding rods 6 to move upward, and the sliding rod 6 drives the adjacent first sliding plate 7 to move upward. At this time, the second limiting column 11 is inserted into the groove of the sliding block 8 under the action of the adjacent spring, so when the first sliding plate 7 moves upward, it will not drive the sliding block 8 to move upward, but will draw the liquid in the adjacent second cavity 802 into the adjacent first cavity 801, and the liquid in the second cavity 802 will be reduced, so that the two sealing plates 9 move toward each other.

[0033] When the first sliding plate 7 moves upward to its upper side and contacts the sliding block 8, the sealing plate 9 on the left separates from the No. 1 pipe 2 and enters the adjacent second cavity 802, and the sealing plate 9 on the right separates from the No. 2 pipe 3 and enters the adjacent second cavity 802. At this time, the first limiting column 10 is inserted into the groove of the adjacent sealing plate 9 under the action of the adjacent spring, and then the first sliding plate 7 drives the sliding block 8 to move upward. When the sliding block 8 moves upward, the groove of the sliding block 8 squeezes the second limiting column 11, causing the second limiting column 11 to move to the left and compress the adjacent spring. When the sliding block 8 moves to its lower side higher than the upper side of the No. 1 pipe 2 and the No. 2 pipe 3, the hydraulic rod 4 stops working and drives the sliding block 8 to stop moving. At this time, the device is opened, and the oil flows through the No. 1 pipe 2 to the shell 1 and then to the No. 2 pipe 3.

[0034] When the gate is closed, the telescopic end of the control hydraulic rod 4 is extended, and the telescopic end of the hydraulic rod 4 drives the connecting plate 5 to move downward, and the connecting plate 5 drives the two sliding rods 6 to move, and the sliding rod 6 drives the adjacent first sliding plate 7 to move downward. At this time, the two sealing plates 9 are respectively limited by the adjacent first limiting columns 10 to move back and forth, so the two first sliding plates 7 drive the sliding block 8 to move downward through the liquid in the adjacent first cavity 801. When the sliding block 8 moves to its lower side and contacts the lower side of the inside of the shell 1, the connection between the No. 1 pipe 2 and the No. 2 pipe 3 is cut off. At this time, the sliding block 8 continues to move downward, and the middle part of the lower side of the sliding block 8 first contacts the lower side of the inside of the shell 1, and then the elastic part of the lower side of the sliding block 8 is squeezed and deformed, and the oil between the sliding block 8 and the lower side of the shell 1 is gradually squeezed to the left and right sides, thereby discharging the oil in the shell 1, and preventing the oil that has accumulated for a long time in the shell 1 from solidifying and clogging the pipeline.

[0035] When the lower side of the sliding block 8 is completely fitted with the lower side of the shell 1, the second limiting column 11 is reinserted into the groove of the sliding block 8 under the action of the adjacent spring. At this time, the hydraulic rod 4 continues to drive the two first sliding plates 7 to move downward, and the first sliding plates 7 squeeze the liquid in the adjacent first cavity 801 into the adjacent second cavity 802. The liquid in the second cavity 802 increases, and the two sealing plates 9 symmetrically distributed in the center move back to back. When the sealing plates 9 move, they squeeze the adjacent first limiting columns 10. The first limiting columns 10 move upward to compress the adjacent springs, and the two sealing plates 9 move to the separated After contacting the No. 1 pipe 2 and the No. 2 pipe 3, the first sliding plate 7 continues to move downward, thereby pressurizing the two sealing plates 9, and enhancing the sealing effect between the two sealing plates 9 and the No. 1 pipe 2 and the No. 2 pipe 3 respectively. When the lower side of the first sliding plate 7 contacts the sliding block 8, the hydraulic rod 4 stops working, and the gate is closed at this time. In the process of opening and closing the above-mentioned gate, the two sealing plates 9 do not rub against the shell 1, the No. 1 pipe 2 and the No. 2 pipe 3 during movement, thereby reducing the wear of the sealing plates, thereby ensuring the sealing effect of the device and extending the service life of the device.

[0036] Embodiment 2: Based on embodiment 1, Figure 2 , Figure 3 and Figure 8As shown, it also includes a connecting tube 12, which is slidably connected to the left side of the No. 2 pipe 3. A fixed shell 13 is fixedly connected to the upper side of the No. 2 pipe 3. The fixed shell 13 is provided with a slide groove. The slide groove of the fixed shell 13 is connected to the slide groove of the No. 2 pipe 3. A sliding column 14 is slidably connected in the fixed shell 13. The sliding column 14 consists of a cylinder and a connecting block. The connecting block part of the sliding column 14 is located in the slide groove of the fixed shell 13 and slides. The right curved part of the longitudinal section of the connecting tube 12 is streamlined. The No. 2 pipe 3 is provided with a diameter change. The longitudinal section of the diameter change inside the No. 2 pipe 3 is curved. The line is streamlined to reduce the flow resistance of oil. When the oil flowing through the connecting tube 12 and the No. 2 pipe 3 passes through, the oil is gently guided to reduce the vibration caused by the impact of the oil. The No. 2 pipe 3 is provided with a slide groove, which is slidably connected with the connecting block part of the sliding column 14. The slide groove of the No. 2 pipe 3 is located on the upper side of the No. 2 pipe 3 (the position of the slide groove on the No. 2 pipe 3 is opposite to the direction in which the oil in the No. 2 pipe 3 is subjected to gravity, that is, when the gravity of the oil in the No. 2 pipe 3 is downward, the slide groove is located on the upper side of the No. 2 pipe 3), which is used to discharge the oil entering the slide groove of the No. 2 pipe 3. When When the device is closed, the oil in the chute of the No. 2 pipe 3 flows into the No. 2 pipe 3, the left side of the sliding column 14 is fixedly connected to the right side of the connecting tube 12, the connecting tube 12 contacts and cooperates with the No. 1 pipe 2, and the connecting tube 12 moves to the left to contact with the No. 1 pipe 2, so that the oil in the No. 1 pipe 2 enters the No. 2 pipe 3 through the connecting tube 12. An annular groove is provided on the side of the No. 1 pipe 2 close to the shell 1. The inner side of the groove of the No. 1 pipe 2 is made of elastic material, which is used to cooperate with the connecting tube 12 to form a seal, and the groove of the No. 1 pipe 2 includes three diameters of large, medium and small. The diameter on the right side of the groove is The largest diameter is medium in the middle, the diameter on the left is equal to the inner diameter of the No. 1 pipe 2, and the diameter of the part between the largest diameter and the medium diameter changes evenly. There is a plane between the medium diameter and the smallest diameter. The large diameter is larger than the outer diameter of the connecting tube 12, the medium diameter is smaller than the outer diameter of the connecting tube 12 but larger than its inner diameter, so that the connecting tube 12 is easy to insert into the No. 1 pipe 2. When the connecting tube 12 is inserted into the No. 1 pipe 2, the two are squeezed against each other to improve the sealing effect. The small diameter is equal to the inner diameter of the connecting tube 12, so that the oil can flow smoothly from the No. 1 pipe 2 into the connecting tube 12.

[0037] like Figure 2 and Fig. 9As shown, a second sliding plate 15 is slidably connected to the upper side of the shell 1, and the second sliding plate 15 is squeezed and matched with the connecting plate 5. A spring is arranged between the upper side of the second sliding plate 15 and the shell 1, and the spring is used to reset the second sliding plate 15. Two symmetrically distributed limit blocks 16 are fixedly connected to the shell 1, and the two limit blocks 16 are limit-matched with the second sliding plate 15. When the second sliding plate 15 moves downward to contact with the limit blocks 16, it cannot continue to move. The second sliding plate 15 is slidably connected to the telescopic end of the hydraulic rod 4, and liquid is injected between the upper side of the second sliding plate 15 and the shell 1, and liquid is injected between the right side of the sliding column 14 and the fixed shell 13. The part of the fixed shell 13 injected with liquid is connected to the part of the shell 1 injected with liquid through a pipeline. When the second sliding plate 15 moves upward, the liquid between it and the shell 1 is squeezed into the fixed shell 13 through the pipeline, thereby pushing the sliding column 14 to move to the left.

[0038] When the gate is opened, the connecting plate 5 contacts the second sliding plate 15. At this time, the telescopic end of the hydraulic rod 4 continues to shorten, driving the connecting plate 5 to move upward. The connecting plate 5 drives the second sliding plate 15 to move upward and compress the adjacent spring. The second sliding plate 15 squeezes the liquid between it and the shell 1, so that the liquid inside enters between the fixed shell 13 and the sliding column 14 through the pipeline. The amount of liquid between the fixed shell 13 and the sliding column 14 increases, pushing the sliding column 14 to drive the connecting cylinder 12 to move leftward, and the connecting cylinder 12 moves to contact the groove of the No. 1 pipe 2 and continues to move. The connecting cylinder 12 squeezes the elastic part in the groove of the No. 1 pipe 2, thereby forming a seal. When the connecting cylinder 12 contacts the left side of the groove of the No. 1 pipe 2, the hydraulic rod 4 stops working. At this time, the oil flows to the connecting cylinder 12 through the No. 1 pipe 2, and then flows to the fixed shell 13, thereby avoiding the oil from entering the irregular cross-section of the shell 1 during the flow process to form turbulence and cause the vibration of the device, thereby reducing the vibration of the device and extending the service life of the device.

[0039] When closing the gate, the hydraulic rod 4 is controlled to extend, and the telescopic end of the hydraulic rod 4 drives the connecting plate 5 to move downward. At this time, the second sliding plate 15 moves downward with the connecting plate 5 under the action of the adjacent spring. When the second sliding plate 15 moves downward, the liquid between the fixed shell 13 and the sliding column 14 is drawn back into the shell 1, and the liquid between the fixed shell 13 and the sliding column 14 is reduced, so that the sliding column 14 drives the connecting tube 12 to move to the right. When the second sliding plate 15 moves downward to contact with the two limit blocks 16, the sliding column 14 drives the connecting tube 12 to return to its original position, and then the hydraulic rod 4 continues to extend to close the gate. The closing process is the same as above.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. An underwater hydraulically controlled gate valve for oil production using a Christmas tree, characterized by: The invention comprises a shell (1), one side of the shell (1) is connected to a first pipe (2), the other side of the shell (1) is connected to a second pipe (3), a hydraulic rod (4) is fixedly connected to a side of the shell (1) away from the first pipe (2) and the second pipe (3), a telescopic end of the hydraulic rod (4) is located in the shell (1) and is fixedly connected to a connecting plate (5), a side of the connecting plate (5) away from the hydraulic rod (4) is fixedly connected to a sliding rod (6) distributed symmetrically in the center, a side of the sliding rod (6) away from the connecting plate (5) is fixedly connected to a first sliding plate (7), a sliding block (8) is slidably connected in the shell (1), and the sliding block (8) is provided with a first cavity (801) distributed symmetrically in the center, The first sliding plate (7) is located in the adjacent first cavity (801) and slides therein; the sliding block (8) is provided with a second cavity (802) distributed symmetrically with respect to the center; a sealing plate (9) is slidably connected to the second cavity (802); a portion of the first cavity (801) located on the side of the adjacent first sliding plate (7) away from the adjacent sliding rod (6) is filled with liquid; a sealed space formed by the second cavity (802) and the adjacent sealing plate (9) is filled with liquid; a portion of the second cavity (802) filled with liquid is connected to a portion of the adjacent first cavity (801) filled with liquid; and the first tube (2) and the second tube (3) are respectively extruded and matched with the adjacent sealing plate (9).

2. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 1 is characterized by: The back sides of the sealing plates (9) which are symmetrically distributed around the center are all made of elastic material and are used to form a seal.

3. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 1 is characterized by: The lower side of the sliding block (8) is pressed into engagement with the lower side of the shell (1); the portion where the sliding block (8) engages with the shell (1) is made of elastic material; the curvature of the lower side of the longitudinal section of the sliding block (8) is greater than the curvature of the lower side of the longitudinal section of the shell (1).

4. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 3 is characterized by: The sliding block (8) is slidably connected to a first limiting column (10) which is centrally symmetrically distributed, a spring is arranged between a side of the first limiting column (10) away from the adjacent sealing plate (9) and the sliding block (8), and the sealing plate (9) is provided with a groove which cooperates with the adjacent first limiting column (10) in limiting manner.

5. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 4 is characterized by: The housing (1) is slidably connected to a second limiting column (11), a spring is provided between the second limiting column (11) and the housing (1), and the sliding block (8) is provided with a groove that cooperates with the second limiting column (11) in limiting manner.

6. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 1, characterized in that: The invention also comprises a connecting tube (12), wherein the connecting tube (12) is slidably connected to a side of the No. 2 pipe (3) close to the shell (1), the No. 2 pipe (3) is fixedly connected to a fixed shell (13), a sliding column (14) is slidably connected to the fixed shell (13), the No. 2 pipe (3) is provided with a sliding groove, the fixed shell (13) is connected to the No. 2 pipe (3) through the sliding groove, the sliding column (14) is slidably matched with the sliding groove of the No. 2 pipe (3), the sliding column (14) is fixedly connected to a side of the connecting tube (12) away from the shell (1), and the connecting tube (12) is in contact with the No. 1 pipe (2).

7. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 6 is characterized by: The chute of the No. 2 pipe (3) is located on the upper side of the No. 2 pipe (3) and is used to discharge the liquid that has entered the chute of the No. 2 pipe (3).

8. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 6, characterized in that: A groove is provided on one side of the first pipe (2) close to the shell (1); the inner side of the groove of the first pipe (2) is made of elastic material, and the groove of the first pipe (2) includes three diameters: large, medium and small. The large diameter is larger than the outer diameter of the connecting tube (12); the medium diameter is smaller than the outer diameter of the connecting tube (12) but larger than its inner diameter; and the small diameter is equal to the inner diameter of the connecting tube (12).

9. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 8, characterized in that: The curved portion of the longitudinal section of the connecting tube (12) close to the sliding column (14) is streamlined, and a diameter change portion is provided inside the second tube (3). The longitudinal section curve of the diameter change portion inside the second tube (3) is streamlined, so as to reduce the flow resistance of the liquid.

10. The underwater hydraulically controlled gate valve for oil production using a Christmas tree according to claim 6, characterized in that: A second sliding plate (15) is slidably connected to a side of the housing (1) away from the sliding block (8), the second sliding plate (15) is pressed and matched with the connecting plate (5), a spring is arranged between the second sliding plate (15) and the side of the housing (1) away from the sliding block (8), symmetrically distributed limit blocks (16) are fixedly connected to the housing (1), the symmetrically distributed limit blocks (16) are all limitedly matched with the second sliding plate (15), the second sliding plate (15) is slidably connected to the telescopic end of the hydraulic rod (4), liquid is injected between a side of the second sliding plate (15) away from the symmetrically distributed limit blocks (16) and the housing (1), liquid is injected between a side of the sliding column (14) away from the housing (1) and the fixed housing (13), and a portion of the fixed housing (13) injected with liquid is connected to a portion of the housing (1) injected with liquid via a pipeline.

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