High temperature and high pressure double seal double adjustment needle valve

Abstract

The present invention relates to the technical field of needle valves, and discloses a high-temperature and high-pressure double-sealed double-adjustable needle valve, comprising a valve body and a valve stem assembly, wherein a feed channel, a discharge channel and a connecting cavity are arranged in the valve body, wherein the inner end of the feed channel is divided into an upper channel and a lower channel, wherein the upper channel is connected to the bottom surface of the connecting cavity located at the upper part of the valve body, and the lower channel is connected to the top surface of the connecting cavity located at the lower part of the valve body, and the valve stem assembly comprises an inner valve stem, wherein the inner valve stem is arranged in the valve body along its own axial sliding, wherein the inner end of the inner valve stem penetrates the connecting cavity and reaches the connecting point between the feed channel and the connecting cavity, and a fixed sealing assembly is arranged between the valve stem assembly and the valve body, wherein the fixed sealing assembly comprises a packing ring and a packing gland, and a plurality of packing rings are arranged in a stacked manner. The present invention can solve or at least alleviate the problem of easy wear and leakage of the existing needle valve, and enhance the sealing performance of the high-temperature and high-pressure double-sealed double-adjustable needle valve.

Description

Technical Field

[0001] The invention relates to the technical field of needle valves, and in particular to a high-temperature and high-pressure double-sealed double-adjustable needle valve. Background Art

[0002] The valve core of the needle valve is a pointed cone, which is inserted into the valve seat like a needle, hence the name of the needle valve. The needle valve is a valve with simple structure, convenient operation, good sealing performance and high adjustment accuracy, but it also has some disadvantages, mainly including:

[0003] ‌1. Easy to wear. The valve core and valve seat of the needle valve are usually made of metal, which is easy to wear during long-term use, causing valve leakage. In addition, the valve stem of the needle valve is relatively slender and is also easily damaged if it is hit by external force.

[0004] 2. The fluid resistance is large. The needle valve requires a large force when opening and closing because its design makes the fluid encounter greater resistance when passing through the valve. Especially in the case of high-pressure fluid, in order to ensure the sealing performance, the sealing packing ring needs to be compressed and fit tightly with the valve stem. Although the sealing performance is improved, the torque required for opening and closing is also increased, and the wear of the packing ring is also accelerated.

[0005] 3. Not suitable for media with particles, high viscosity, or easy to coke: The design of the needle valve makes it unsuitable for handling media containing particles, high viscosity, or easy to coke, because these characteristics may cause damage or blockage to the internal structure of the valve.

[0006] In order to solve the problem that needle valves are prone to leakage under high-pressure environments, an invention patent with publication number CN115681594A discloses a high-temperature and high-pressure double-seal double-adjustable needle valve, including a valve body, a protection box is installed on the top of the valve body, and a protection cover, a protection box and a fixing groove are provided. When the valve stem is not in use, the operator pulls the protection cover to make the protection cover drive the connecting shaft to move upward, and then rotates the protection cover so that the protection cover is located above the protection box, and then loosens the protection cover so that the supporting spring pushes the moving block to move downward, so that the connecting shaft drives the protection cover to move downward, so that the bottom end of the protection cover is inserted into the fixing groove, and the positioning block is located in the fixing block. Then the operator loosens the fixing rod, and at this time, the connecting spring pushes one end of the clamping column to be inserted into the positioning block to fix the protection cover, thereby closing the protection box, protecting the valve stem and the valve seat, and preventing the valve stem and the valve seat from being eroded by the outside world, so that the valve stem cannot rotate. However, its structure is not only complicated, but also can only prevent the valve stem and valve seat from being bonded together and unable to rotate due to external erosion. It cannot solve the problem of valve stem wear and sealing, nor can it solve the problem that the needle valve itself has large fluid resistance and is difficult to rotate to open and close. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art, solve or at least alleviate the problem of easy wear and leakage of the existing needle valve, and provide a high-temperature and high-pressure double-sealed double-adjustable needle valve.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a high-temperature and high-pressure double-sealed double-adjustable needle valve, comprising a valve body and a valve stem assembly, wherein a feed channel, a discharge channel and a connecting cavity are arranged in the valve body, and the two connecting cavities are respectively located at the upper and lower parts of the valve body, and the inner end of the feed channel is divided into an upper channel and a lower channel, the upper channel is connected to the bottom surface of the connecting cavity located at the upper part of the valve body, and the lower channel is connected to the top surface of the connecting cavity located at the lower part of the valve body, and the inner ends of the two discharge channels are respectively connected to the side surfaces of the two connecting cavities; the two valve stem assemblies are respectively located at one end of the two connecting cavities away from the feed channel, and the valve stem assembly comprises an inner valve stem, and the inner valve stem slides along its own axial direction It is arranged in the valve body, and the inner end of the inner valve stem penetrates the connecting cavity and reaches the connecting point between the feed channel and the connecting cavity; a fixed sealing assembly is arranged between the valve stem assembly and the valve body, and a sealing cavity and a pressing cavity are arranged in sequence from the inside to the outside at one end of the connecting cavity away from the feed channel, and the fixed sealing assembly includes a packing ring and a packing gland, and the packing ring is an annular flat plate made of elastic material, the packing ring is sleeved on the inner valve stem and located in the sealing cavity, and several packing rings are stacked, and the packing gland is in the shape of a circular tube, and the circumferential outer wall of the packing gland is threadedly fitted in the pressing cavity, and the inner end of the packing gland presses the packing ring in the sealing cavity, and the inner valve stem is axially slidably arranged in the packing gland.

[0009] In order to further realize the present invention, the following technical solutions may be preferably selected:

[0010] Preferably, the fixed sealing assembly also includes a packing baffle and a packing pressure pad, both of which are made of hard material. The packing baffle is located at the innermost side of the sealing cavity, and the packing pressure pad is slidably sleeved on the inner valve stem. The lower part of the packing pressure pad extends into the sealing cavity and abuts against the packing ring, and the upper part of the packing pressure pad is located in the clamping cavity and abuts against the inner end of the packing gland.

[0011] Preferably, the fixed sealing assembly also includes an anti-rotation mechanism, which includes an anti-rotation plate and an anti-rotation screw. The outer side of the upper cross-section of the packing gland is polygonal and extends outward from the valve body. An opening is provided in the middle of the anti-rotation plate. The shape of the opening is the same as the outer side of the upper part of the packing gland. The anti-rotation plate is fitted on the packing gland through the opening, and the anti-rotation screw fastens the anti-rotation plate and the valve body together.

[0012] Preferably, the valve stem assembly comprises an outer valve stem, which is threadedly mounted on a packing gland, the outer end of the inner valve stem is rotatably engaged with the inner end of the outer valve stem, and the outer end of the outer valve stem extends outward from the packing gland and is fixedly provided with a handle.

[0013] Preferably, a movable sealing assembly is also provided between the valve stem assembly and the valve body, and the movable sealing assembly includes a movable chamber, a sealing ring and a connecting channel. The movable chamber is located on the side of the sealing chamber close to the connecting chamber. The sealing ring is a circular ring body made of elastic material. The inner side of the sealing ring is sealed to the outer wall of the inner valve stem. A gap is left between the outer wall of the sealing ring and the outer wall of the movable chamber. One end of the connecting channel is connected to the feed channel and the other end is connected to the movable chamber.

[0014] Preferably, a groove is provided in the middle of the circumferential outer wall of the sealing ring. After the fluid enters the active cavity through the feed channel and the connecting channel, the circumferential inner wall of the sealing ring is tightly fitted to the circumferential outer wall of the inner valve stem, the upper end face of the sealing ring is tightly fitted to the upper end face of the active cavity, and the lower end face of the sealing ring is tightly fitted to the lower end face of the active cavity.

[0015] Preferably, the movable sealing assembly further comprises an opening and closing mechanism, the opening and closing mechanism comprises an opening and closing path and an opening and closing block, the opening and closing path intersects with the connecting channel, and the opening and closing block is sealingly and slidably disposed in the opening and closing path;

[0016] The opening and closing block moves with the inner valve stem. When the inner end of the inner valve stem reaches the connection between the feed channel and the connecting cavity, the opening and closing block is located at the intersection of the opening and closing channel and the connecting channel, and the connecting channel is in a closed state; when the inner end of the inner valve stem is separated from the connection between the feed channel and the connecting cavity, the opening and closing block moves away from the intersection of the opening and closing channel and the connecting channel, and the connecting channel is in an open state.

[0017] Preferably, the inner end of the opening and closing channel is connected to the feed channel, and a connecting rope is arranged between the opening and closing block and the inner valve stem, one end of the connecting rope is fixedly connected to the inner end of the opening and closing block and the other end is fixedly connected to the middle part of the inner end of the inner valve stem, and a plurality of pull balls are arranged in an array at intervals on the connecting rope, and the diameter of the pull ball is greater than the diameter of the connecting rope, and the diameter of the pull ball is not greater than one third of the inner diameter of the feed channel.

[0018] Preferably, a tension spring is provided at one end of the opening and closing channel away from the feed channel, one end of the tension spring is fixedly connected to the outer end of the opening and closing channel and the other end is fixedly connected to the outer end of the opening and closing block.

[0019] Preferably, the inner end of the inner valve stem is in the shape of a truncated cone with a larger outer side and a smaller inner side, and the inner end of the inner valve stem is a hollow shell, and an opening is provided at the center of the inner end surface of the inner valve stem; when the inner end of the inner valve stem reaches the connection between the feed channel and the connecting cavity, the fluid in the feed channel enters the internal space of the inner end of the inner valve stem through the opening, so that the inner end of the inner valve stem expands outward and fits tightly to the connection between the feed channel and the connecting cavity.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention realizes a one-in-two-out structure through one feed channel and two discharge channels, so as to achieve the effect of independently controlling the on-off of two pipelines, thereby expanding the scope of application.

[0022] 2. The present invention fixes the setting of the sealing component, presses the packing ring into the pressing cavity through the packing gland, and adjusts the height position of the packing gland, which can change the friction and sealing degree between the packing ring and the inner valve stem, so as to make the wear and sealing between the packing ring and the inner valve stem in the optimal state. When adjusting the height position of the packing gland, it does not affect the position state of the inner valve stem, thereby avoiding affecting the working state of the needle valve.

[0023] 3. The present invention also performs primary sealing on the inner valve stem through a movable sealing assembly. The fixed sealing assembly is located outside the movable sealing assembly. The leaked fluid passes through the movable sealing assembly and then the fixed sealing assembly performs secondary sealing. At this time, the pressure of the fluid is much lower than the pressure before the primary sealing, so reliable sealing can be achieved, and the compression degree of the packing ring of the fixed sealing assembly can be reduced, thereby reducing the wear between the packing ring and the inner valve stem.

[0024] 4. The pressure of the fluid in the needle valve makes the sealing ring fit tightly to the inner valve stem and the active cavity. The greater the pressure, the better the sealing performance, which ensures the sealing effect. The smaller the pressure, the smaller the pressure of the sealing ring on the inner valve stem, which reduces the wear between the sealing ring and the inner valve stem. At the same time, the opening and closing state of the opening and closing channel is controlled by the opening and closing block. When the inner end of the inner valve stem reaches the connection between the feed channel and the connecting cavity, there is no fluid at the connection between the inner valve stem and the sealing ring. At this time, the opening and closing channel is closed, and the sealing ring does not press the inner valve stem tightly, reducing the torque required for the needle valve to open; when the inner end of the inner valve stem is separated from the connection between the feed channel and the connecting cavity, the fluid flows to the connection between the inner valve stem and the sealing ring. At this time, the opening and closing channel is opened, and the fluid enters the active cavity to press the sealing ring tightly to the inner valve stem, ensuring the sealing effect.

[0025] 5. The opening and closing block is linked to the inner valve stem through the connecting rope to realize the automatic displacement of the opening and closing block. At the same time, the connecting rope moves in the feed channel, and the pull ball on it can actively tend to the movement of the fluid in the feed channel. When the feed channel is blocked due to particles, high viscosity, and easy coking, the movement of the connecting rope can dredge the blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention.

[0027] Figure 2 It is a structural cross-sectional view of the present invention.

[0028] Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle.

[0029] Figure 4 It is a cross-sectional view of the valve body of the present invention.

[0030] Figure 5 It is a cross-sectional view of the inner valve stem of the present invention.

[0031] The accompanying drawings are marked as follows:

[0032] 1-valve body; 2-feed channel; 3-discharge channel; 4-connecting chamber; 5-inner valve stem; 6-sealing chamber; 7-pressing chamber; 8-packing ring; 9-packing gland; 10-packing baffle; 11-packing pressure pad; 12-anti-rotation plate; 13-anti-rotation screw; 14-outer valve stem; 15-movable chamber; 16-sealing ring; 17-connecting channel; 18-opening and closing channel; 19-opening and closing block; 20-connecting rope; 21-tension spring. DETAILED DESCRIPTION

[0033] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1

[0036] Needle valves have the disadvantage of being easy to wear. The valve core and valve seat of needle valves are usually made of metal, which are easy to wear during long-term use, and are more likely to wear the sealing material, causing valve leakage. Especially in the case of high-pressure fluid, in order to ensure the sealing performance, the packing ring 8 used for sealing needs to be pressed tightly to make it fit closely with the valve stem. When the valve stem moves, it is easier to wear the sealing ring 16 and cause leakage.

[0037] Reference Figure 1-Figure 5 A high-temperature and high-pressure double-sealed double-adjustable needle valve comprises a valve body 1 and a valve stem assembly. A feed channel 2, a discharge channel 3 and a connecting chamber 4 are arranged in the valve body 1. The two connecting chambers 4 are respectively located in the upper and lower parts of the valve body 1. The inner end of the feed channel 2 is divided into an upper channel and a lower channel. The upper channel is connected to the bottom surface of the connecting chamber 4 located in the upper part of the valve body 1, and the lower channel is connected to the top surface of the connecting chamber 4 located in the lower part of the valve body 1. The inner ends of the two discharge channels 3 are respectively connected to the sides of the two connecting chambers 4; in this embodiment, the feed channel 2 is T-shaped, and the two ends of the vertical section of the feed channel 2 are respectively connected to the two connecting chambers 4.

[0038] The two valve stem assemblies are respectively located at one end of the two connecting cavities 4 away from the feed channel 2. The valve stem assembly includes an inner valve stem 5, which is slidably arranged in the valve body 1 along its own axial direction. The inner end of the inner valve stem 5 penetrates into the connecting cavity 4 and reaches the connecting point between the feed channel 2 and the connecting cavity 4.

[0039] A fixed sealing assembly is arranged between the valve stem assembly and the valve body 1. A sealing chamber 6 and a pressing chamber 7 are arranged in sequence from the inside to the outside at one end of the connecting chamber 4 away from the feed channel 2. The fixed sealing assembly includes a packing ring 8 and a packing gland 9. The packing ring 8 is an annular flat plate made of elastic material. The packing ring 8 is sleeved on the inner valve stem 5 and is located in the sealing chamber 6. Multiple packing rings 8 are stacked. The packing gland 9 is in the shape of a circular tube. The circumferential outer wall of the packing gland 9 is threadedly sleeved in the pressing chamber 7. The inner end of the packing gland 9 presses the packing ring 8 in the sealing chamber 6, and the inner valve stem 5 is axially slidably arranged in the packing gland 9.

[0040] The fixed sealing assembly also includes a packing baffle 10 and a packing pressure pad 11, both of which are made of hard material. The packing baffle 10 is located at the innermost side of the sealing chamber 6, and the packing pressure pad 11 is slidably sleeved on the inner valve stem 5. The lower part of the packing pressure pad 11 extends into the sealing chamber 6 and abuts against the packing ring 8, and the upper part of the packing pressure pad 11 is located in the clamping chamber 7 and abuts against the inner end of the packing gland 9; the packing baffle 10 is located below the packing ring 8 and directly contacts the fluid in the needle valve to prevent the fluid from directly impacting the packing ring 8, thereby preventing the packing ring 8 from axial deformation and affecting the sealing effect; the packing pressure pad 11 presses the packing ring 8 from top to bottom, and the packing pressure pad 11 will not rotate with the packing gland 9 to prevent the packing gland 9 from directly contacting the packing ring 8 and causing wear when the packing gland 9 rotates and rises.

[0041] In order to keep the packing gland 9 in a fixed position, the fixed sealing assembly also includes an anti-rotation mechanism, which includes an anti-rotation plate 12 and an anti-rotation screw 13. The outer side of the upper cross-section of the packing gland 9 is polygonal and extends outward from the valve body 1. An opening is provided in the middle of the anti-rotation plate 12, and the shape of the opening is the same as the outer side of the upper part of the packing gland 9. The anti-rotation plate 12 is fitted onto the packing gland 9 through the opening, and the anti-rotation screw 13 fastens the anti-rotation plate 12 and the valve body 1 as a whole.

[0042] In order to adjust the height position of the inner valve stem 5 and prevent the inner valve stem 5 from rotating to reduce wear, the valve stem assembly includes an outer valve stem 14, which is threadedly fitted on the packing gland 9, and the outer end of the inner valve stem 5 is rotatably engaged with the inner end of the outer valve stem 14, and the outer end of the outer valve stem 14 extends outward from the packing gland 9 and is fixedly provided with a handle.

[0043] Under high temperature and high pressure environment, the inner valve stem 5 and the valve body 1 are both made of metal material. In order to ensure the sealing performance when the inner end of the inner valve stem 5 reaches the connection between the feed channel 2 and the connecting chamber 4, the inner end of the inner valve stem 5 is in the shape of a truncated cone with a larger outside and a smaller inside, and the inner end of the inner valve stem 5 is a hollow shell, and an opening is provided at the center of the inner end surface of the inner valve stem 5; when the inner end of the inner valve stem 5 reaches the connection between the feed channel 2 and the connecting chamber 4, the fluid in the feed channel 2 enters the internal space of the inner end of the inner valve stem 5 through the opening, so that the inner end of the inner valve stem 5 expands outward and fits tightly to the connection between the feed channel 2 and the connecting chamber 4; even if the inner valve stem 5 or the valve body 1 has a certain degree of wear and tear, the high-pressure fluid will cause the inner end of the inner valve stem 5 to expand outward, and it will not affect the sealing effect.

[0044] The packing ring 8 is pressed into the pressing chamber 7 by the packing gland 9. By adjusting the height position of the packing gland 9, the friction force and the sealing degree between the packing ring 8 and the inner valve stem 5 can be changed, so that the wear and sealing between the packing ring 8 and the inner valve stem 5 are in the optimal state. When adjusting the height position of the packing gland 9, the position state of the inner valve stem 5 is not affected, so as to avoid affecting the working state of the needle valve.

[0045] Embodiment 2

[0046] During use, the fluid resistance in the needle valve is large, and the needle valve requires greater force when opening and closing. This is because its design makes the fluid encounter greater resistance when passing through the valve, especially in the case of high-pressure fluid. In order to ensure the sealing performance, the sealing packing ring 8 needs to be compressed to make it fit tightly with the valve stem. This not only increases the torque required for opening and closing, but also accelerates the wear of the packing ring 8.

[0047] To this end, a movable sealing assembly is also provided between the valve stem assembly and the valve body 1, and the movable sealing assembly includes a movable chamber 15, a sealing ring 16 and a connecting channel 17. The movable chamber 15 is located on the side of the sealing chamber 6 close to the connecting chamber 4. The sealing ring 16 is a circular ring body made of elastic material. The inner side of the circumference of the sealing ring 16 is sealed to the outer wall of the circumference of the inner valve stem 5. A gap is left between the outer wall of the circumference of the sealing ring 16 and the outer wall of the movable chamber 15. One end of the connecting channel 17 is connected to the feed channel 2 and the other end is connected to the movable chamber 15.

[0048] In order to optimize the product structure and ensure the sealing effect of the sealing ring 16, a groove is provided in the middle of the circumferential outer wall of the sealing ring 16. After the fluid enters the active chamber 15 through the feed channel 2 and the connecting channel 17, the circumferential inner wall of the sealing ring 16 is tightly fitted to the circumferential outer wall of the inner valve stem 5, the upper end face of the sealing ring 16 is tightly fitted to the upper end face of the active chamber 15, and the lower end face of the sealing ring 16 is tightly fitted to the lower end face of the active chamber 15.

[0049] The inner valve stem 5 is sealed at the primary level by the movable sealing assembly, and the fixed sealing assembly is located outside the movable sealing assembly. After the leaked fluid passes through the movable sealing assembly, the fixed sealing assembly performs secondary sealing. At this time, the pressure of the fluid is much lower than the pressure before the primary sealing, which can achieve reliable sealing and reduce the degree of compression of the packing ring 8 of the fixed sealing assembly to reduce the torque required when the inner valve stem 5 is raised and lowered, and also reduce the wear between the packing ring 8 and the inner valve stem 5. The pressure of the fluid in the needle valve makes the sealing ring 16 fit tightly to the inner valve stem 5 and the movable cavity 15. The greater the pressure, the better the sealing performance, which ensures the sealing effect. The smaller the pressure, the smaller the pressure of the sealing ring 16 on the inner valve stem 5, which reduces the wear between the sealing ring 16 and the inner valve stem 5.

[0050] Embodiment 3

[0051] It is also found during use that when the fluid drives the sealing ring 16 to press the inner valve stem 5, the sealing ring 16 still has relatively large wear. At the same time, when the fluid pressure in the needle valve is high, the torque required to open it is large.

[0052] In this embodiment, the movable sealing assembly also includes an opening and closing mechanism, which includes an opening and closing path 18 and an opening and closing block 19. The opening and closing path 18 and the connecting channel 17 intersect with each other. The opening and closing block 19 is sealingly slidably arranged in the opening and closing path 18. When the opening and closing block 19 is located at the intersection of the opening and closing path 18 and the connecting channel 17, the connecting channel 17 is in a closed state.

[0053] The opening and closing block 19 moves with the inner valve stem 5. When the inner end of the inner valve stem 5 reaches the connection between the feed channel 2 and the connecting chamber 4, the opening and closing block 19 is located at the intersection of the opening and closing channel 18 and the connecting channel 17, and the connecting channel 17 is in a closed state; when the inner end of the inner valve stem 5 is separated from the connection between the feed channel 2 and the connecting chamber 4, the opening and closing block 19 is away from the intersection of the opening and closing channel 18 and the connecting channel 17, and the connecting channel 17 is in an open state.

[0054] The opening and closing state of the opening and closing channel 18 is controlled by the opening and closing block 19. When the inner end of the inner valve stem 5 reaches the connection between the feed channel 2 and the connecting chamber 4, there is no fluid at the connection between the inner valve stem 5 and the sealing ring 16. At this time, the opening and closing channel 18 is closed, and the sealing ring 16 does not press the inner valve stem 5 tightly, thereby reducing the torque required for opening the needle valve; when the inner end of the inner valve stem 5 is separated from the connection between the feed channel 2 and the connecting chamber 4, the fluid flows to the connection between the inner valve stem 5 and the sealing ring 16. At this time, the opening and closing channel 18 is opened, and the fluid enters the active chamber 15 to press the sealing ring 16 against the inner valve stem 5, thereby ensuring the sealing effect.

[0055] In addition, it is found that when the fluid is a medium with particles, high viscosity, and easy to coke, the feed channel 2 of the needle valve is prone to blockage, affecting the use of the needle valve, and in severe cases, the entire needle valve may be scrapped.

[0056] To this end, the inner end of the opening and closing channel 18 is connected to the feed channel 2, and a connecting rope 20 is arranged between the opening and closing block 19 and the inner valve stem 5, one end of the connecting rope 20 is fixedly connected to the inner end of the opening and closing block 19 and the other end is fixedly connected to the middle part of the inner end of the inner valve stem 5, and a plurality of pull balls are arranged in an interval array on the connecting rope 20, and the diameter value of the pull ball is larger than the diameter value of the connecting rope 20, and the diameter value of the pull ball is not greater than one third of the inner diameter value of the feed channel 2.

[0057] The opening and closing block 19 is linked to the inner valve stem 5 through the connecting rope 20 to realize automatic displacement of the opening and closing block 19. At the same time, the connecting rope 20 moves in the feed channel 2. The pull ball thereon can actively tend to move the fluid in the feed channel 2. When the feed channel 2 is blocked due to particles, high viscosity, and easy coking of the fluid, the movement of the connecting rope 20 can clear the blockage.

[0058] When the needle valve is closed, the inner valve stem 5 moves inward. At this time, the fluid pressure in the opening and closing channel 18 will drive the opening and closing block 19 to move toward the intersection of the opening and closing channel 18 and the connecting channel 17. However, when the fluid pressure is relatively low, the opening and closing block 19 may not move into place. In this embodiment, a tension spring 21 is provided at one end of the opening and closing channel 18 away from the feed channel 2. One end of the tension spring 21 is fixedly connected to the outer end of the opening and closing channel 18 and the other end is fixedly connected to the outer end of the opening and closing block 19. The tension spring 21 generates a pulling force on the opening and closing block 19 to ensure that the opening and closing block 19 can move to the intersection of the opening and closing channel 18 and the connecting channel 17. At the same time, the tension of the tension spring 21 is also transmitted to the inner valve stem 5 through the connecting rope 20, thereby reducing the torque required for closing the needle valve.

[0059] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-temperature and high-pressure double-sealed double-adjustable needle valve, comprising a valve body and a valve stem assembly, characterized in that: The valve body is provided with a feed channel, a discharge channel and a connecting cavity, the two connecting cavities are respectively located at the upper part and the lower part of the valve body, the inner end of the feed channel is divided into an upper channel and a lower channel, the upper channel is connected to the bottom surface of the connecting cavity located at the upper part of the valve body, the lower channel is connected to the top surface of the connecting cavity located at the lower part of the valve body, and the inner ends of the two discharge channels are respectively connected to the side surfaces of the two connecting cavities; The two valve stem assemblies are respectively located at one end of the two communication chambers away from the feed channel, and the valve stem assembly includes an inner valve stem, which is slidably arranged in the valve body along its own axial direction, and the inner end of the inner valve stem penetrates the communication chamber and reaches the connection point between the feed channel and the communication chamber; A fixed sealing assembly is arranged between the valve stem assembly and the valve body, and a sealing chamber and a pressing chamber are arranged in sequence from the inside to the outside at one end of the communicating chamber away from the feed channel, and the fixed sealing assembly includes a packing ring and a packing gland, the packing ring is an annular flat plate made of elastic material, the packing ring is sleeved on the inner valve stem and is located in the sealing chamber, a plurality of packing rings are stacked, the packing gland is in the shape of a circular tube, the outer circumferential wall of the packing gland is threadedly sleeved in the pressing chamber, the inner end of the packing gland presses the packing ring in the sealing chamber, and the inner valve stem is axially slidably arranged in the packing gland; A movable sealing assembly is also provided between the valve stem assembly and the valve body, and the movable sealing assembly includes a movable chamber, a sealing ring and a connecting channel. The movable chamber is located on the side of the sealing chamber close to the connecting chamber. The sealing ring is a circular ring made of elastic material. The inner side of the sealing ring is sealed to the outer wall of the inner valve stem. A gap is left between the outer wall of the sealing ring and the outer wall of the movable chamber. One end of the connecting channel is connected to the feed channel and the other end is connected to the movable chamber.

2. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 1, characterized in that: The fixed sealing assembly also includes a packing baffle and a packing pressure pad, both of which are made of hard material. The packing baffle is located at the innermost side of the sealing cavity, and the packing pressure pad sliding sleeve is arranged on the inner valve stem. The lower part of the packing pressure pad extends into the sealing cavity and abuts against the packing ring, and the upper part of the packing pressure pad is located in the clamping cavity and abuts against the inner end of the packing gland.

3. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 2, characterized in that: The fixed sealing assembly also includes an anti-rotation mechanism, which includes an anti-rotation plate and an anti-rotation screw. The outer side of the cross-section of the upper part of the packing gland is polygonal and extends outward from the valve body. An opening is provided in the middle of the anti-rotation plate. The shape of the opening is the same as the outer side of the upper part of the packing gland. The anti-rotation plate is fitted on the packing gland through the opening, and the anti-rotation screw fastens the anti-rotation plate and the valve body as a whole.

4. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 1, characterized in that: The valve stem assembly comprises an outer valve stem, which is threadedly sleeved on a packing gland, an outer end of the inner valve stem is rotatably engaged with an inner end of the outer valve stem, and the outer end of the outer valve stem extends outward from the packing gland and is fixedly provided with a handle.

5. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 1, characterized in that: A groove is provided in the middle of the circumferential outer wall of the sealing ring. After the fluid enters the active cavity through the feed channel and the connecting channel, the circumferential inner wall of the sealing ring is tightly fitted to the circumferential outer wall of the inner valve stem, the upper end face of the sealing ring is tightly fitted to the upper end face of the active cavity, and the lower end face of the sealing ring is tightly fitted to the lower end face of the active cavity.

6. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 1, characterized in that: The movable sealing assembly further comprises an opening and closing mechanism, the opening and closing mechanism comprises an opening and closing path and an opening and closing block, the opening and closing path intersects with the connecting channel, the opening and closing block is sealingly slidably arranged in the opening and closing path, and when the opening and closing block is located at the intersection of the opening and closing path and the connecting channel, the connecting channel is in a closed state; The opening and closing block moves with the inner valve stem. When the inner end of the inner valve stem reaches the connection between the feed channel and the connecting cavity, the opening and closing block is located at the intersection of the opening and closing channel and the connecting channel, and the connecting channel is in a closed state; when the inner end of the inner valve stem is separated from the connection between the feed channel and the connecting cavity, the opening and closing block moves away from the intersection of the opening and closing channel and the connecting channel, and the connecting channel is in an open state.

7. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 6, characterized in that: The inner end of the opening and closing channel is connected to the feed channel, and a connecting rope is arranged between the opening and closing block and the inner valve stem, one end of the connecting rope is fixedly connected to the inner end of the opening and closing block and the other end is fixedly connected to the middle part of the inner end of the inner valve stem, and a plurality of pull balls are arranged in an array at intervals on the connecting rope, and the diameter of the pull ball is greater than the diameter of the connecting rope, and the diameter of the pull ball is not greater than one third of the inner diameter of the feed channel.

8. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 6, characterized in that: A tension spring is arranged at one end of the opening and closing channel away from the feed channel, one end of the tension spring is fixedly connected to the outer end of the opening and closing channel and the other end is fixedly connected to the outer end of the opening and closing block.

9. The high-temperature and high-pressure double-sealed double-adjustable needle valve according to claim 1, characterized in that: The inner end of the inner valve stem is in the shape of a truncated cone with a larger outer side and a smaller inner side, and the inner end of the inner valve stem is a hollow shell, and an opening is arranged at the center of the inner end surface of the inner valve stem; when the inner end of the inner valve stem reaches the connection between the feed channel and the connecting cavity, the fluid in the feed channel enters the internal space of the inner end of the inner valve stem through the opening, so that the inner end of the inner valve stem expands outward and fits tightly to the connection between the feed channel and the connecting cavity.

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