Plunger type isolation valve for large diameter pipelines

Abstract

The present invention provides a plunger-type isolating valve for large-diameter pipelines, which belongs to the field of valves and includes a coaxially arranged valve body and a valve core, the valve core is arranged inside the valve body and the two are slidably connected along the axis thereof, the outer rings at both ends of the valve core are provided with sealing components, the valve body is provided with a side port and a port, in a closed state, the side port is placed between the sealing components at both ends, the inside of the valve body is provided with a positioning block that protrudes inward and limits the valve core, in an open state, the side port and the port are connected, the outside of the valve body is provided with a balancing pipeline connecting an inlet and an outlet, a pressure balancing valve is provided on the balancing pipeline, a closed pressure chamber is formed between the end of the valve body away from the port and the valve core, and the pressure chamber is connected with an operating system. The present invention is suitable for large-diameter pipelines with low frequency of use, and has a simple structure and low cost.

Description

Technical Field

[0001] The invention belongs to the field of valves, and relates to a cut-off valve for a large-diameter pipeline, and in particular to a plunger-type cut-off valve for a large-diameter pipeline. Background Art

[0002] With the development of technology, the production scale and storage and transportation capacity of the equipment are getting larger and larger, resulting in larger and larger pipeline diameters. The valves used for pipeline "head shaking" and maintenance are opened and closed very rarely, and gate valves are currently used to cut off and open the pipeline.

[0003] Gate valves are suitable for large-diameter pipelines and have particularly high requirements for sealing parts, resulting in high costs. For carbon steel pipelines with a diameter of about 800 mm, the cost of a gate valve is around 100,000 yuan. However, with such a low frequency of use, the use of high-cost gate valves will lead to a significant increase in the cost of the entire pipeline. Ball valves or stop valves are not suitable for large-diameter pipeline cut-off functions due to structural limitations. Butterfly valves have poor sealing performance and are therefore rarely used for large-diameter pipeline cut-off functions for toxic and flammable media. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a plunger type isolating valve for large-diameter pipelines, which is suitable for cutting off large-diameter pipelines with low usage frequency and has a simple structure and low cost.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a plunger-type isolating valve for a large-diameter pipeline, comprising a coaxially arranged valve body and a valve core, the valve core is arranged inside the valve body and the two are slidably connected along the axis thereof, the outer rings of both ends of the valve core are provided with sealing components, the valve body is provided with a side port and a port, in a closed state, the side port is placed between the sealing components at both ends, a positioning block is provided inside the valve body which protrudes inward and limits the valve core, and in an open state, the side port and the port are connected;

[0006] A balancing pipeline connecting the side port and the port is provided on the outside of the valve body, and a pressure balancing valve is provided on the balancing pipeline. A closed pressure chamber is formed between the end of the valve body away from the outlet and the valve core, and the pressure chamber is connected to the operating system.

[0007] Furthermore, a flange cover is provided at one end of the valve body away from the port, a fixing bolt is provided on the flange cover, a fixing nut is provided at one end of the valve core close to the fixing bolt, and the fixing bolt passes through the valve body and is connected to the fixing nut.

[0008] Furthermore, a connecting flange is provided on the outer ring of the valve body near one end of the flange cover, and the connecting flange is arranged correspondingly to the flange cover and the two are detachably fixedly connected by bolts.

[0009] Furthermore, the valve body includes a main shell and a sub-shell arranged vertically, the side port is arranged on the sub-shell, the port is arranged on the main shell, and the outer ring of the column shell is provided with a coaxial reinforcement plate, and the reinforcement plate is symmetrically arranged relative to the axis of the sub-shell.

[0010] Furthermore, the valve core includes a core barrel, and the outer rings at both ends of the core barrel are provided with coaxial fixing rings, and the sealing assembly is embedded in the fixing rings.

[0011] Furthermore, the valve body is made of a pipe, and the valve core is welded from profiles into an integrated structure.

[0012] Furthermore, the valve body is a cast one-piece structure, and the valve core is welded from profiles into an one-piece structure.

[0013] Furthermore, the sealing assembly is two sealing rings arranged in parallel.

[0014] Furthermore, the sealing assembly includes a guide ring and a sealing ring arranged in parallel, wherein the guide ring is arranged on the outer ring of the sealing ring, the outer ring of the guide ring is gap-matched with the inner ring of the valve body, and the guide ring is made of PTFE.

[0015] Furthermore, the operating system includes an operating pipeline, which is a three-way structure, one of which is connected to a pressure gauge inspection valve, a pressure gauge is provided at one end of the pressure gauge inspection valve away from the valve body, one is connected to a control valve for input and discharge of air or nitrogen, and one is connected to the pressure chamber.

[0016] Compared with the prior art, the present invention has the following advantages and positive effects.

[0017] 1. The valve core of the present invention moves by pressure difference, and the positioning of the valve core is achieved by the limit block arranged in the valve body. The whole structure changes the structure of the traditional valve. It is used for valves for pipeline conduction or maintenance. The frequency of use of such valves is particularly low. Such structure is simple. On the basis of meeting the use requirements, the structure is simplified, the installation space is small, the pneumatic actuator is simplified, and the opening is convenient, the operation is more convenient and quick, and the cost is greatly reduced. Since there is no valve handle, there is no external leakage, which improves safety.

[0018] 2. After setting the fixing bolts and nuts, the valve core is fixed after it is opened, ensuring the stability of the open state, improving the stability of the entire structure operation state, reducing the dependence on pressure control, further improving safety, and also helping to improve assembly efficiency. The sealing assembly set on the valve core can replace the sealing ring to improve the sealing effect, and the valve core can also be removed to change the valve into a three-way valve, which has a wide range of applications;

[0019] 3. Setting up reinforcement plates can improve the strength of the side openings, thereby improving the strength of the entire structure and ensuring the pressure-bearing capacity of the structure. The sealing components are fixed in an embedded manner, which has higher stability and is not easy to fall off. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is a structural schematic diagram of the plunger-type isolation valve for large-diameter pipelines of the present invention in an open state;

[0022] Figure 2 It is a structural schematic diagram of the plunger-type isolation valve for large-diameter pipelines of the present invention in a closed state;

[0023] Figure 3 The present invention Figure 1 Detail of Part A.

[0024] Reference numerals:

[0025] 1. Valve body; 11. Main shell; 12. Auxiliary shell; 13. Reinforcement plate; 14. Connecting flange; 15. Flange cover; 16. Positioning block; 17. Side port; 18. Port; 19. Pressure chamber; 2. Valve core; 21. Core tube; 22. Sealing assembly; 23. Fixing nut; 24. Fixing ring; 3. Operating system; 31. Pressure gauge inspection valve; 32. Control valve; 33. Pressure gauge; 34. Fixing bolt; 35. Pressure balancing valve. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0029] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 to Figure 3 As shown, a plunger-type isolating valve for a large-diameter pipeline comprises a coaxially arranged valve body 1 and a valve core 2, the valve core 2 is arranged inside the valve body 1 and the two are slidably connected along the axis thereof, the outer rings of both ends of the valve core 2 are provided with sealing components 22, the valve body 1 is provided with a side port 17 and a port 18, in a closed state, the side port 17 is placed between the sealing components 22 at both ends, the inside of the valve body 1 is provided with a positioning block 16 that protrudes inward and limits the valve core 2, and in an open state, the side port 17 and the port 18 are connected;

[0031] A balancing pipeline connecting the side port 17 and the port 18 is provided on the outside of the valve body 1, and a pressure balancing valve 35 is provided on the balancing pipeline. A closed pressure chamber 19 is formed between the end of the valve body 1 away from the port 18 and the valve core 2. The pressure chamber 19 is connected to the operating system 3. The pressure balancing valve 35 realizes the pressure balance between the side port 17 and the port 18, and is not prone to water hammer and pressure difference problems, and the transmission is more stable.

[0032] Preferably, a flange cover 15 is provided at the end of the valve body 1 away from the port 18, and a fixing bolt 34 is provided on the flange cover 15. A fixing nut 23 is provided at the end of the valve core 2 close to the fixing bolt 34, and the fixing bolt 34 passes through the valve body 1 and is connected with the fixing nut 23. After the fixing bolt 34 and the fixing nut 23 are provided, after the valve core 2 is opened, the valve core 2 is fixed, the stability of the open state is ensured, the stability of the operating state of the entire structure is improved, the dependence on pressure control is reduced, the safety is further improved, and it is also beneficial to improve assembly efficiency.

[0033] Preferably, a connecting flange 14 is provided on the outer ring of the valve body 1 near one end of the flange cover 15. The connecting flange 14 and the flange cover 15 are correspondingly arranged and the two are detachably fixedly connected by bolts. The connecting flange 14 and the flange cover 15 have a simple connection structure and adopt a common structure on the market. The subsequent maintenance cost is low and the sealing performance can be guaranteed. The sealing structure at the connection between the two can refer to the flange structure in the existing structure.

[0034] Preferably, the valve body 1 includes a main shell 11 and a sub-shell 12 which are vertically arranged, the side port 17 is arranged on the sub-shell 12, the port 18 is arranged on the main shell 11, and a coaxial reinforcing plate 13 is arranged on the outer ring of the main shell, and the reinforcing plate 13 is symmetrically arranged relative to the axis of the sub-shell 12. The reinforcement plate 13 can improve the strength at the side port 17, thereby improving the strength of the entire structure and ensuring the pressure bearing capacity of the structure. The structural dimensions of the valve body are determined according to the pipeline specifications, medium properties, design temperature and design pressure, and the material, pressure grade and wall thickness of each component are determined. Three positioning blocks 16 are evenly distributed circumferentially for positioning in the closed state. Except for the flange cover 15, after the valve body is assembled, the sealing surface of the main shell is hardened after being machined according to the technical requirements.

[0035] Preferably, the valve core 2 includes a core barrel 21, and the outer rings at both ends of the core barrel 21 are provided with coaxial fixing rings 24. The sealing assembly 22 is embedded in the fixing ring 24. The fixing ring 24 and the core barrel 21 are separately arranged and then welded to form an integrated structure. This facilitates the processing of the fixing ring 24 and reduces the processing cost. The sealing assembly 22 is fixed in an embedded manner, which has higher stability and is not easy to fall off. The core barrel structure size, material, wall thickness, nitrogen filling or air filling are determined according to the pipeline specifications, medium properties, design temperature, and design pressure. The sealing assembly structure and the material of the sealing ring and the size of the fixing nut are determined. Except for the sealing ring, after the valve core is assembled, the groove parts are machined according to the technical requirements.

[0036] Preferably, the valve body 1 is made of a pipe, and the valve core 2 is welded into an integral structure by profiles. The material is easy to obtain, the cost is low, and the strength is high. The pipes and profiles can be set to different thicknesses according to the actual application environment and strength requirements. The specifications can be adjusted and set more conveniently and the versatility is stronger.

[0037] Preferably, the sealing assembly 22 is two sealing rings arranged in parallel, and the sealing rings can be commercially available, so subsequent maintenance is convenient and reliable, and the maintenance cost is lower.

[0038] Preferably, the operating system 3 includes an operating pipeline, which is a three-way structure, one of which is connected to a pressure gauge inspection valve 31, and a pressure gauge 33 is provided at one end of the pressure gauge inspection valve 31 away from the valve body 1, one is connected to a control valve 32 for inputting and discharging air or nitrogen, and one is connected to the pressure chamber 19. It is determined whether the control valve 32 is connected to nitrogen or air according to the physical properties of the medium. If inflammable and explosive items or dangerous items are transmitted, nitrogen needs to be supplied. The pressure is adjusted by flushing and discharging nitrogen, and the relative sliding of the valve core 2 relative to the valve body 1 is realized. It is determined whether a pressure balance line is required according to the flow direction of the medium. It is determined whether the control valve 32 is connected to nitrogen or air according to the physical properties of the medium. The parallel movement of the valve core is controlled by filling and exhausting. The pressure gauge is used to monitor the operating state of the valve core, and the control valve has a leak detection function. The fixing bolt and the fixing nut are used to fix the valve core in the open state. The operating system makes full use of the principle of pressure balance to operate the valve, making it more convenient to operate. The larger the valve caliber, the more obvious the advantage.

[0039] The above structure is suitable for pressure pipes with a design pressure of less than or equal to 1.0 MPa and a design temperature of less than or equal to 150 degrees. It has low cost, simple operation, convenience and reliability.

[0040] Embodiment 2: Different from the above embodiments, the valve body 1 is an integral casting structure, and the valve core 2 is welded from profiles into an integral structure. The casting structure can further increase the pressure resistance, and in the case of mass production, the mold is used for integral molding, and mass production has lower costs. When the design pressure is greater than 1.0 MPa and the design temperature is greater than 150 degrees, the casting structure is used.

[0041] Embodiment 3: Different from the above embodiments, the sealing assembly 22 includes a guide ring and a sealing ring arranged in parallel, wherein the guide ring is arranged on the outer ring of the sealing ring, and the outer ring of the guide ring is clearance-matched with the inner ring of the valve body 1. The guide ring is made of PTFE, and the specific material is set and selected according to actual conditions. After the guide ring is set, the movement accuracy of the valve core 2 relative to the valve body 1 is improved, and the movement of the valve core 2 can be guided to ensure better fit between the fixing bolt 34 and the fixing nut 23, thereby improving the fit accuracy. The hardness of the guide ring is matched with the hardness of the inner wall of the valve body 1 and is set according to different pressure conditions. If the pressure is large, a guide ring with higher hardness is used. The inner wall of the main shell 11 can be provided with a nitriding layer to improve the strength and wear resistance of the inner wall of the main shell 11, thereby improving the service life of the main shell 11.

[0042] In the actual working process, after the pipeline is laid, when it is necessary to connect the side port 17 and the port 18, the structure of the present application is started. When it is necessary to open the port, the pressure of the port 18 is increased, and the pressure of the sealing chamber is reduced at the same time. The pressure difference is used to realize the movement of the valve core 2 in the direction away from the port 18. After the movement, the side port 17 and the port 18 are connected, and the connection of the pipeline is realized. Under normal use, once the side port 17 and the port 18 are connected, the pipeline is always in use, and the present structure is in a normally open state. When the pipeline needs to be repaired or maintained, it needs to be maintained in sections. At this time, the present structure should be in a closed state, and the pressure of the sealing chamber is increased by operating the system 3. Under the action of the pressure difference, the valve core 2 moves toward the direction of the port 18. When the sealing components 22 at both ends of the valve core 2 are located at both ends of the side port 17, sealing is achieved. After sealing, the pipeline maintenance can be realized. The present structure is simple, low in cost, and easy to operate.

[0043] When this structure is actually used, it needs to be inspected according to the requirements of "Petrochemical Valve Inspection and Management Specification" SH3518. A new type of plunger-type isolation valve in this embodiment is applied to a process gas pipeline with a DN800, a design pressure of 0.4MPa, and a design temperature of 130°C. Its function is to "shake the head" for the pre-built device. At this time, a flange, a flange cover 15, a gasket, bolts, and nuts are added to the end of the auxiliary shell 12 for sealing. After installation, the valve is in an open state, and the fixing bolts 34 and the fixing nuts 23 cooperate to fix the valve core 2. The medium is sealed by the flange cover 15 to achieve "zero" leakage.

[0044] After the new device is built, without stopping the original device, the two devices are connected by "shaking the head". The control valve 32 is filled with nitrogen to push the valve core 2 to move horizontally. At this time, the pressure gauge 33 should be observed at all times. The opening of the control valve 32 is adjusted to make the value of the pressure gauge 33 change smoothly, that is, the valve core 2 moves smoothly. When the value of the pressure gauge 33 reaches the medium operating pressure and remains stable, that is, the valve core 2 reaches the positioning block 16, the process gas is isolated, and the valve is used only once when the two devices are connected.

[0045] After the device is connected, the control valve 32 is deflated. At this time, the pressure gauge 33 should be observed at all times. The opening of the control valve 32 is adjusted to make the value of the pressure gauge 33 change smoothly, that is, the valve core 2 moves smoothly. When the value of the pressure gauge 33 is zero, that is, the valve core 2 reaches the flange cover 15, the valve is fully opened, and then the valve core 2 is fixed with the fixing bolt 34 and the fixing nut 23.

[0046] When the device is inspected and repaired again, the valve core 2 is taken out and the valve becomes a three-way valve. The plunger type isolation valve has completed its mission.

[0047] And need to pay attention to the following issues:

[0048] (1) This valve is mainly used for positive pressure fluid pipelines with a nominal diameter ≥ DN400;

[0049] (2) When the design pressure is greater than 1.0 MPa and the design temperature is greater than 150°C, the valve body 1 shall be integrally cast;

[0050] (3) The core tube 21 should be designed to withstand external pressure, and its end plate should take into account the most unfavorable external pressure effect;

[0051] (4) Determine whether to fill the core tube 21 with nitrogen or air according to the physical properties of the medium;

[0052] (5) Determine whether to fill the pressurized exhaust line with nitrogen or air based on the physical properties of the medium;

[0053] (6) When the valve is switched on and off, the medium operating pressure must be understood and the control valve 32 must be adjusted according to the medium operating pressure;

[0054] (7) The structure of the sealing component 22 and the material of the sealing ring are determined according to the physical properties of the medium, the design temperature, and the design pressure.

[0055] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. The plunger-type isolation valve for large-diameter pipelines is used on process gas pipelines with DN800, design pressure 0.4MPa, and design temperature 130℃. It is a pre-built device with a swing head. The two devices are connected through the swing head. The plunger-type isolation valve for large-diameter pipelines is only used once when the two structures are connected. It is characterized by: It comprises a coaxially arranged valve body and valve core, the valve core is arranged inside the valve body and the two are slidably connected along the axis thereof, the valve core moves by pressure difference, the outer rings at both ends of the valve core are provided with sealing components, the valve body is provided with side ports and ports, in a closed state, the side ports are placed between the sealing components at both ends, a positioning block is provided inside the valve body that protrudes inwards and limits the valve core, and in an open state, the side ports and ports are connected; The outside of the valve body is provided with a balancing pipeline connecting the side port and the port, and a pressure balancing valve is provided on the balancing pipeline. A closed pressure chamber is formed between the end of the valve body away from the port and the valve core, and the pressure chamber is connected to the operating system; A flange cover is provided at one end of the valve body away from the port, a fixing bolt is provided on the flange cover, a fixing nut is provided at one end of the valve core close to the fixing bolt, and the fixing bolt passes through the valve body and is connected to the fixing nut; The outer ring of the valve body close to one end of the flange cover is provided with a connecting flange, and the connecting flange is arranged correspondingly to the flange cover and the two are detachably fixedly connected by bolts; The valve core comprises a core barrel, the outer rings at both ends of the core barrel are provided with coaxial fixing rings, and the sealing assembly is embedded in the fixing rings; The sealing assembly comprises a guide ring and a sealing ring arranged in parallel, wherein the guide ring is arranged on the outer ring of the sealing ring, and the outer ring of the guide ring is in clearance fit with the inner ring of the valve body; The operating system includes an operating pipeline, which is a three-way structure, one of which is connected to a pressure gauge inspection valve, a pressure gauge is provided at one end of the pressure gauge inspection valve away from the valve body, one is connected to a control valve for input and discharge of air or nitrogen, and one is connected to a pressure chamber.

2. The plunger-type isolation valve for large-diameter pipelines according to claim 1 is characterized in that: The valve body comprises a main shell and a sub-shell arranged vertically, the side port is arranged on the sub-shell, the port is arranged on the main shell, the outer ring of the main shell is provided with a coaxial reinforcement plate, and the reinforcement plate is symmetrically arranged relative to the axis of the sub-shell.

3. The plunger-type isolation valve for large-diameter pipelines according to claim 1 is characterized in that: The valve body is made of a pipe, and the valve core is welded into an integral structure by profiles.

4. The plunger-type isolation valve for large-diameter pipelines according to claim 1 is characterized in that: The valve body is a cast integral structure, and the valve core is welded into an integral structure by profiles.

5. The plunger-type isolation valve for large-diameter pipelines according to claim 1 is characterized in that: The sealing assembly is two sealing rings arranged in parallel.

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