A LNG valve bidirectional metal seal assembly suitable for ultra-low temperature environment
By using low-temperature resistant materials and sealing packing to design a bidirectional metal sealing assembly for LNG valves, the problem of insufficient valve sealing in ultra-low temperature environments has been solved, achieving stable operation and high-efficiency sealing at around -162°C.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SPECIAL VALVE JIANGSU FLUID MASCH MFG CO LTD
- Filing Date
- 2025-08-06
- Publication Date
- 2026-06-23
AI Technical Summary
Existing LNG cryogenic valves are susceptible to impact from liquefied natural gas during opening and closing, and the sealing ball of the valve is not sufficiently tight, making them prone to leakage, especially in ultra-low temperature environments.
A bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments was designed. The valve body, valve ball, side valve seat, and bottom valve seat are made of cryogenic materials. The assembly uses a combination of sealing packing and disc springs to ensure high sealing performance of the valve in the closed state and prevent LNG gas leakage.
Maintaining good mechanical and sealing properties at extremely low temperatures prevents leakage or failure caused by thermal expansion and contraction, ensuring stable operation and safety of the valve.
Smart Images
Figure CN224397181U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of LNG valve technology, and more specifically to a bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments. Background Technology
[0002] NG valves are crucial in cryogenic environments, playing a key role in the storage, transportation, and processing of liquefied natural gas (LNG). LNG, a form of natural gas stored at extremely low temperatures (around -162°C), places extremely high demands on the cryogenic resistance, sealing performance, and operational reliability of valve materials. Under cryogenic conditions, LNG valves must maintain their structural integrity and functional effectiveness to ensure the safe operation of the LNG system. This requires valve materials to possess not only excellent cryogenic toughness to prevent brittle fracture at extremely low temperatures but also good cryogenic sealing performance to prevent LNG leakage. Furthermore, valve design must consider the thermal expansion and contraction effects under cryogenic conditions to ensure tight closure and smooth opening.
[0003] Existing LNG cryogenic valves are subjected to the impact of liquefied natural gas during opening and closing, and the internal sealing valve ball is prone to insufficient sealing due to the ultra-low temperature. Therefore, a new technical solution is needed to address this issue. Utility Model Content
[0004] The purpose of this invention is to provide a bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments, which solves the problem that existing cryogenic LNG valves are subject to the impact of liquefied natural gas during the opening and closing process, and the sealing ball inside the valve is prone to insufficient sealing due to the influence of cryogenic temperatures.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a bidirectional metal sealing assembly for an LNG valve suitable for cryogenic environments, comprising: a valve body, a side cover provided on the side of the valve body, and connecting flanges provided on both sides of the side cover and the valve body, which are connected to an LNG transmission pipeline through the connecting flanges; a fixed mounting base provided on the top of the valve body, and a connecting seat provided on the upper part of the mounting base; the connecting seat and the mounting base are fixedly fastened by bolts; a fixed connecting rod provided on the upper part of the connecting seat, and a screw cap provided on the top of the connecting rod; a valve stem and valve... The rod extends into the interior of the valve body. The screw cap is fitted onto the surface of the valve rod and threadedly connected to the connecting rod. The valve body and the side cover have flow channels inside, and the valve body has a valve ball inside. The valve ball has a through hole inside, which is connected to the flow channel. Side valve seats are provided on both sides of the valve ball, and the inner side of the side valve seats has a bowl-shaped structure. The sealing surface of the valve ball and the side valve seats are fitted together. The bottom of the valve body has a bottom cover, and the upper part of the bottom cover has a fixed shaft. The upper part of the fixed shaft has a bottom valve seat, and the interior of the bottom valve seat has a semi-arc structure and wraps around the bottom of the valve ball.
[0006] In a preferred embodiment of this utility model, a first sealing filler is provided in the threaded connection groove between the screw cap and the connecting rod.
[0007] In a preferred embodiment of this utility model, a second sealing packing is provided at the connection between the valve stem and the mounting base.
[0008] In a preferred embodiment of this utility model, the top of the connecting rod is provided with an mounting plate and the upper part of the mounting plate is provided with a fixing frame. The fixing frame is rectangular in structure, and a fixing bolt is provided between the fixing frame and the mounting plate, and the fixing frame is fixedly connected to the mounting plate by the fixing bolt.
[0009] In a preferred embodiment of this utility model, the top of the valve stem is provided with an adjusting block having a rectangular structure.
[0010] In a preferred embodiment of the present invention, the top of the valve ball is provided with a groove and the bottom of the valve stem is provided with a snap-fit block that engages with it.
[0011] In a preferred embodiment of this utility model, a connecting post is provided on the side of the side cover and the surface of the connecting post is provided with threads. The valve body and the connecting post of the side cover are threadedly connected and reinforced by bolts.
[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0013] This invention features a side cover on the side of the valve body, with connecting flanges on both sides of the side cover and the valve body. These flanges connect to an LNG delivery pipeline. A mounting base is fixedly connected to the top of the valve body, and a connecting seat is located on top of the mounting base. The connecting seat and mounting base are fixed together by bolts. A connecting rod is fixedly connected to the connecting seat, with a screw cap on top. A valve stem is located inside the connecting rod, extending into the valve body. The screw cap is fitted onto the surface of the valve stem and threadedly connected to the connecting rod. Flow channels are provided inside the valve body and side cover, and a valve ball is located inside the valve body. The valve ball has a through hole that communicates with the flow channels. Movement of the valve stem causes the valve ball to rotate, gradually aligning the through hole and flow channels inside the valve ball. LNG gas can then smoothly pass through the through hole and flow channels inside the valve ball, opening the valve and ensuring normal LNG delivery. Side valve seats are located on both sides of the valve ball, with the inner side of the side valve seats shaped like a bowl. The valve features a unique structural design where the sealing surface of the valve ball fits snugly into the side valve seat. A bottom cover is located at the bottom of the valve body, with a fixed shaft on top. Above the fixed shaft is a bottom valve seat, its interior featuring a semi-circular structure that encloses the bottom of the valve ball. The tight fit between the valve ball, side valve seat, and bottom valve seat, along with the functions of the first and second sealing packings, ensures high sealing performance when the valve is closed, preventing LNG gas leakage. A disc spring assembly is installed between the bottom valve seat and the valve ball. The valve stem surface is chrome-plated or nitrided. The side and bottom valve seats are made of nickel-based alloys, while the valve ball is made of cobalt-chromium-tungsten alloy. Key components such as the valve body, side cover, valve ball, side valve seat, and bottom valve seat are all made of cryogenic materials, maintaining excellent mechanical and sealing performance even in ultra-low temperature environments. This ensures stable operation of the valve at extremely low temperatures of around -162°C, preventing leakage or failure due to thermal expansion and contraction or material brittle fracture. Meanwhile, the disc spring assembly between the bottom valve seat and the valve ball can also compensate for dimensional changes caused by thermal expansion and contraction to a certain extent, further improving the stability and sealing of the valve. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0015] Figure 2 This is a side view of the structure of this utility model;
[0016] Figure 3 This is a cross-sectional structural diagram of the present invention.
[0017] In the diagram: 1. Valve body; 2. Side cover; 3. Connecting flange; 4. Mounting seat; 5. Connecting seat; 6. Connecting rod; 7. Mounting plate; 8. Fixing bracket; 9. Fixing bolt; 10. Threaded cap; 11. Valve stem; 12. Adjusting block; 13. First sealing packing; 14. Second sealing packing; 15. Valve ball; 16. Flow channel; 17. Slot; 18. Snap-fit block; 19. Side valve seat; 20. Bottom cover; 21. Fixing shaft; 22. Bottom valve seat; 23. Connecting column. Detailed Implementation
[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0019] Please see Figure 1-3This utility model provides a technical solution: a bidirectional metal sealing assembly for an LNG valve suitable for cryogenic environments, comprising: a valve body 1, a side cover 2 on the side of the valve body 1, and connecting flanges 3 on both sides of the side cover 2 and the valve body 1, which are connected to an LNG transmission pipeline through the connecting flanges 3; a fixed mounting seat 4 on the top of the valve body 1, and a connecting seat 5 on the upper part of the mounting seat 4, the connecting seat 5 and the mounting seat 4 being fixedly fastened by bolts; a fixed connecting rod 6 on the upper part of the connecting seat 5, and a screw cap 10 on the top of the connecting rod 6; a valve stem 11 inside the connecting rod 6, extending into the interior of the valve body 1; and the screw cap 10 being sleeved on the surface of the valve stem 11 and threadedly connected to the connecting rod 6. The valve body 1 and side cover 2 are internally provided with flow channels 16, and the valve body 1 is internally provided with a valve ball 15. The valve ball 15 is internally provided with a through hole that communicates with the flow channel 16. Side valve seats 19 are provided on both sides of the valve ball 15, and the inner side of the side valve seats 19 is shaped like a bowl. The sealing surface of the valve ball 15 and the side valve seats 19 are interlocked. The bottom of the valve body 1 is provided with a bottom cover 20, and the upper part of the bottom cover 20 is provided with a fixed shaft 21. The upper part of the fixed shaft 21 is provided with a bottom valve seat 22, and the interior of the bottom valve seat 22 is shaped like a semi-arc and wraps around the bottom of the valve ball 15. Side covers 2 are provided on the sides of the valve body 1, and connecting flanges 3 are provided on both sides of the side covers 2 and the valve body 1. The valve body 1 is connected to the LNG transmission pipeline through the connecting flanges 3. The valve body 1 is connected to the mounting base 4, which is fixedly connected to the top of the valve body 1. A connecting seat 5 is located on the upper part of the mounting base 4. The connecting seat 5 and the mounting base 4 are fixedly connected by bolts. A connecting rod 6 is fixedly connected to the upper part of the connecting seat 5, and a screw cap 10 is located on the top of the connecting rod 6. A valve stem 11 is located inside the connecting rod 6 and extends into the interior of the valve body 1. The screw cap 10 is fitted onto the surface of the valve stem 11 and threadedly connected to the connecting rod 6. A flow channel 16 is located inside the valve body 1 and the side cover 2. A valve ball 15 is located inside the valve body 1. The valve ball 15 has a through hole that communicates with the flow channel 16. Movement of the valve stem 11 causes the valve ball 15 to rotate, and the through hole inside the valve ball 15 gradually aligns with the flow channel 16, allowing LNG gas to flow through. The valve opens smoothly through the through-hole and flow channel 16 inside the valve ball 15, ensuring the normal delivery of LNG. Side valve seats 19 are provided on both sides of the valve ball 15, with the inner side of each side valve seat 19 having a bowl-shaped structure. The sealing surface of the valve ball 15 and the side valve seats 19 fit together. A bottom cover 20 is provided at the bottom of the valve body 1, and a fixed shaft 21 is provided on the upper part of the bottom cover 20. A bottom valve seat 22 is provided on the upper part of the fixed shaft 21, with the inner side of the bottom valve seat 22 having a semi-arc structure and wrapping around the bottom of the valve ball 15. The tight fit between the valve ball 15, the side valve seats 19, and the bottom valve seat 22, along with the function of the first sealing packing 13 and the second sealing packing 14, together ensure the high sealing performance of the valve in the closed state, preventing LNG gas leakage.A disc spring assembly is installed between the bottom valve seat 22 and the valve ball 15. The valve stem 11 is chrome-plated or nitrided. The side valve seats 19 and 22 are made of nickel-based alloy, and the valve ball 15 is made of cobalt-chromium-tungsten alloy. Key components such as the valve body 1, side cover 2, valve ball 15, side valve seat 19, and bottom valve seat 22 are all made of low-temperature resistant materials, maintaining good mechanical and sealing performance even in ultra-low temperature environments. This ensures stable operation of the valve at extremely low temperatures of around -162°C, preventing leakage or failure due to thermal expansion and contraction or material brittle fracture. Simultaneously, the disc spring assembly between the bottom valve seat 22 and the valve ball 15 also compensates for dimensional changes caused by thermal expansion and contraction to a certain extent, further improving the valve's stability and sealing performance.
[0020] Further improvements, such as Figure 3 As shown: The threaded connection groove between the screw cap 10 and the connecting rod 6 is provided with a first sealing packing 13. The first sealing packing 13 can enhance the sealing between the screw cap 10 and the connecting rod 6, prevent LNG gas in the ultra-low temperature environment from leaking through the threaded connection, and improve the overall sealing performance of the valve.
[0021] Further improvements, such as Figure 3 As shown: A second sealing packing 14 is provided at the connection between the valve stem 11 and the mounting base 4. The second sealing packing 14 ensures a tight connection between the valve stem 11 and the mounting base 4, preventing LNG gas from leaking from the gap between the valve stem 11 and the mounting base 4, and further improving the sealing performance and safety of the valve.
[0022] Further improvements, such as Figure 1 As shown: The top of the connecting rod 6 is provided with a mounting plate 7 and the upper part of the mounting plate 7 is provided with a fixing frame 8. The fixing frame 8 is rectangular in structure. The fixing frame 8 and the mounting plate 7 are provided with fixing bolts 9 and the fixing frame 8 is fixedly connected to the mounting plate 7 through the fixing bolts 9. This arrangement can effectively protect the valve stem 11 connection at the top of the connecting rod 6.
[0023] Further improvements, such as Figure 1 As shown: The top of the valve stem 11 is provided with an adjustment block 12 with a rectangular structure. The design of the adjustment block 12 facilitates precise adjustment of the valve stem 11, making the opening and closing of the valve more flexible and controllable.
[0024] Further improvements, such as Figure 3 As shown: The top of the valve ball 15 is provided with a slot 17 and the bottom of the valve stem 11 is provided with a snap-fit block 18 that fits into it. The fitting design of the slot 17 and the snap-fit block 18 enhances the connection strength between the valve ball 15 and the valve stem 11, and prevents the valve ball 15 from separating from the valve stem 11 due to thermal expansion and contraction in ultra-low temperature environments.
[0025] Further improvements, such as Figure 3 As shown: The side cover 2 has a connecting post 23 on its side, and the surface of the connecting post 23 is threaded. The valve body 1 and the connecting post 23 of the side cover 2 are threaded together and reinforced with bolts. This connection method not only enhances the connection strength between the valve body 1 and the side cover 2, but also facilitates the disassembly and maintenance of the valve. At the same time, the combination of threaded connection and bolt reinforcement improves the valve's impact resistance and durability in ultra-low temperature environments.
[0026] Working principle: When the valve is closed, the valve ball 15 fits tightly with the side valve seat 19 and the bottom valve seat 22 through its sealing surface, forming a highly efficient sealing barrier. Simultaneously, the first sealing packing 13 and the second sealing packing 14 enhance the sealing between the screw cap 10 and the connecting rod 6, and between the valve stem 11 and the mounting base 4, respectively. Together, they ensure high sealing performance of the valve in the closed state, effectively preventing LNG gas leakage, improving the safety and reliability of the valve, and ensuring the stable operation of the LNG system. When the valve needs to be opened, the operator rotates the valve stem 11 using the adjusting block 12. The rotation of the valve stem 11 causes the valve ball 15 to rotate accordingly, gradually aligning the through hole inside the valve ball 15 with the flow channel 16. As the alignment between the through-hole and the flow channel 16 increases, LNG gas begins to flow smoothly through the through-hole and flow channel 16 inside the valve ball 15, thus opening the valve. The valve opening process is smooth, flexible, and fast, improving the delivery efficiency of the LNG system. When the valve needs to be closed, the operator rotates the adjusting block 12 in the opposite direction, causing the valve stem 11 and the valve ball 15 to rotate. During the rotation, the sealing surface of the valve ball 15 gradually fits tightly with the side valve seat 19 and the bottom valve seat 22, forming a seal. At the same time, the first sealing packing 13 and the second sealing packing 14 again play their role, ensuring high sealing performance after the valve is closed. The valve closing process is reliable and rapid, and the sealing performance after closure is good, effectively preventing LNG gas leakage and ensuring the safety of the LNG system. The bidirectional metal seal of the LNG valve, through its unique design and structure, achieves efficient, stable, and safe operation in ultra-low temperature environments.
[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0028] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can refer to mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc., are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.
[0029] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments, characterized in that: include: A valve body (1) is provided with a side cover (2) on its side and a connecting flange (3) on both sides of the valve body (1). The valve body (1) is connected to the LNG pipeline through the connecting flange (3). A fixed mounting seat (4) is provided on the top of the valve body (1) and a connecting seat (5) is provided on the upper part of the mounting seat (4). The connecting seat (5) and the mounting seat (4) are fixed together by bolts. A fixed connecting rod (6) is provided on the upper part of the connecting seat (5) and a screw cap (10) is provided on the top of the connecting rod (6). A valve stem (11) is provided inside the connecting rod (6) and extends into the interior of the valve body (1). The screw cap (10) is sleeved on the surface of the valve stem (11) and connected to the connecting rod (6). 6) The valve body (1) and the side cover (2) are connected by threads. The valve body (1) and the side cover (2) are provided with flow channels (16) and the valve body (1) is provided with valve ball (15). The valve ball (15) is provided with through holes and the through holes are connected to the flow channels (16). The valve ball (15) is provided with side valve seats (19) on both sides and the inner side of the side valve seats (19) is provided with a bowl-shaped structure. The sealing surface of the valve ball (15) and the side valve seats (19) are fitted together. The bottom of the valve body (1) is provided with a bottom cover (20) and the upper part of the bottom cover (20) is provided with a fixed shaft (21). The upper part of the fixed shaft (21) is provided with a bottom valve seat (22) and the interior of the bottom valve seat (22) is provided with a semi-arc structure and wraps around the bottom of the valve ball (15).
2. The bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: The threaded connection groove between the screw cap (10) and the connecting rod (6) is provided with a first sealing filler (13).
3. The bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: A second sealing packing (14) is provided at the connection between the valve stem (11) and the mounting base (4).
4. The bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: The top of the connecting rod (6) is provided with a mounting plate (7) and the upper part of the mounting plate (7) is provided with a fixing frame (8). The fixing frame (8) is rectangular in shape. A fixing bolt (9) is provided between the fixing frame (8) and the mounting plate (7) and the fixing frame (8) is fixedly connected to the mounting plate (7) through the fixing bolt (9).
5. A bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: The valve stem (11) is provided with an adjustment block (12) in a rectangular structure at its top.
6. A bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: The valve ball (15) has a slot (17) at its top and a snap block (18) at the bottom of the valve stem (11) that engages with it.
7. A bidirectional metal sealing assembly for LNG valves suitable for cryogenic environments according to claim 1, characterized in that: The side cover (2) is provided with a connecting post (23) and the surface of the connecting post (23) is provided with threads. The valve body (1) and the connecting post (23) of the side cover (2) are threaded together and reinforced by bolts.