Double eccentric hemispherical valve Guo Fengzhong Abstract The performance, structure characteristics and application range of double eccentric hemispherical valve are introduced.
Keywords double eccentricity; hemispherical valve; ball valve; floating; meshing; sealing pair; hemisphere
1 Overview With the continuous development of the industry, the demand for ball valves, especially high temperature and high pressure, is increasing. Ball valves are required to have higher wear resistance, erosion resistance, high temperature resistance, and corrosion resistance. While the traditional full-diameter ball valve has a surface hardening process such as surfacing welding and spraying, the service life, cost, and performance of the conventional full-ball valve cannot meet the requirements for use, such as industrial silicon, coal chemical, and blast furnace gas. Gas and other harsh conditions. The double eccentric hemispherical valve is a new product developed by taking advantage of the advantages of ball valves, V-shaped valves, and track ball valves of different structures. The ball valve adopts double eccentricity seal structure, which has small wear, small torque, good sealing performance and long service life. The valve seat and hemisphere are treated with a special hardening process, which is especially suitable for the requirements of wear resistance, erosion resistance, corrosion resistance and high temperature resistance under severe working conditions.
2 structural characteristics 2, 1 hemisphere double hemispherical hemisphere ball valve (Figure 1) hemisphere double eccentric design, sealing effect is reliable, instantly disengaged, small torque, long service life. Can be applied in the harsh conditions of conveying granular media. The structural principle is the offset size a of the centerline of the hemisphere (Fig. 2) and the valve stem centerline, and the offset size of the centerline of the valve seat. When fully opened, the ball and the valve seat are completely disengaged, and there is a certain clearance. The radius of gyration is divided into For the long radius and short radius, the tangent to the long-radius trajectory will form an angle θ with the valve seat sealing surface. When the valve is opened and closed, the hemisphere has a gradual disengagement from the valve seat surface (as shown in Figure 10). The core has been completely disengaged from the action of progressive extrusion, thereby reducing mechanical wear and scratches between the valve seat and the hemisphere during opening and closing and increasing the service life.
2.2 Seat (1) The valve seat (figure 3) adopts a floating design to reduce the processing difficulty and ensure that the centerline of the seat coincides with the center point of the hemispherical spherical surface, thereby improving the sealing performance. The valve seat and the valve body have a gap d. During the assembly, the hemispherical positioning can be used to automatically align the midline to ensure that the valve seat sealing surface and the hemispherical sphere are in full contact, thereby solving the leakage due to machining error and improving the performance of the ball valve. life.
(2) The seal between the valve seat and the valve body adopts a hard seal structure, which is suitable for high temperature and high pressure working conditions. Valve seat and valve body seal contact surface size c
The value is small, and the precision of their sealing surfaces is high. During assembly, the retainer is installed with an electric impact wrench. Not only is the retainer meshed with the valve body to prevent loosening, but also the valve seat frictionally rotates, conforming to the principle of mechanical vibration engagement and making the valve seat. Reliable sealing with valve body.
(3) The valve seat and the valve body, the valve seat and the hemisphere adopt two hard seals, so the valve can be used in high temperature and high pressure conditions.
2, 3 other components The overall use of modular design of the valve, the structure is simple, reliable, high versatility. The stem adopts an anti-outflow structure. The driving methods are diversified, and the connecting dimensions of the valve stem, the bracket and the actuator are in conformity with the ISO5211 standard, and can be directly combined with various specification implementing agencies. The commonly used driving methods include manual, pneumatic, hydraulic, gas-liquid linkage and electric, etc., thereby improving the performance of the double eccentric hemispherical valve.
3 Scope of use Double eccentric hemispherical valves are suitable for valves of various general industry requirements, such as water, sewage, wastewater, steam, gas, pulp and other media. If the sealing pair adopts Cr-Mn-Si cemented carbide and has the functions of fire resistance, explosion proof and anti-static, it is suitable for medium and high temperature medium requirements such as gas, coke oven gas, water gas and natural gas. If the sealing pair (hemisphere, valve seat) and valve body flow channel are treated with tungsten carbide special process, it has the advantages of high efficiency and energy saving, good wear resistance, reliable sealing performance, light operation, rapid opening and closing, long service life, etc. Industrial silicon industry is ideal for valves used on pipelines. Due to the instantaneous detachment of the hemisphere and the valve seat and the instantaneous compaction characteristics, it is suitable for the harsh working conditions that contain particles in the medium. It can be widely used in metallurgy, beneficiation, electricity and other production processes for blast furnace pulverized coal injection, pulverizing system and dust removal system. Various pipeline controls in the. In the process of instantaneous disengagement and instant compaction, the hemisphere and the valve seat have a squeezing effect to remove scale and sticky materials on the sealing surface, which ensures tight and reliable sealing. It is an ideal choice for valves with two-phase mixed fluid media in the process flow, such as easy to deposit sediment, crystallized solution slurry, slurry ash and other processes.
4 Conclusion At present, the double-equivalent hemispherical valve of a variety of specifications has been applied to various projects in different industries, the effect is good, and gradually expand the scope of use.
References [1] Lu Peiwen. Practical Valve Design Manual [M]. Beijing: Mechanical Industry Press, 1992.
[2] Wu Guoxi. Use and Maintenance of Regulators [M]. Beijing: Chemical Industry Press, 1992.
[3] Wang Wenbin. Mechanical Design Handbook, Third Edition [M]. Beijing: Mechanical Industry Press, 1992.
[4] Qu Jingxin, Wang Yuhong. Surface Engineering Handbook [M]. Beijing: Chemical Industry Press, 1992.
(Received date)
Keywords double eccentricity; hemispherical valve; ball valve; floating; meshing; sealing pair; hemisphere
1 Overview With the continuous development of the industry, the demand for ball valves, especially high temperature and high pressure, is increasing. Ball valves are required to have higher wear resistance, erosion resistance, high temperature resistance, and corrosion resistance. While the traditional full-diameter ball valve has a surface hardening process such as surfacing welding and spraying, the service life, cost, and performance of the conventional full-ball valve cannot meet the requirements for use, such as industrial silicon, coal chemical, and blast furnace gas. Gas and other harsh conditions. The double eccentric hemispherical valve is a new product developed by taking advantage of the advantages of ball valves, V-shaped valves, and track ball valves of different structures. The ball valve adopts double eccentricity seal structure, which has small wear, small torque, good sealing performance and long service life. The valve seat and hemisphere are treated with a special hardening process, which is especially suitable for the requirements of wear resistance, erosion resistance, corrosion resistance and high temperature resistance under severe working conditions.
2 structural characteristics 2, 1 hemisphere double hemispherical hemisphere ball valve (Figure 1) hemisphere double eccentric design, sealing effect is reliable, instantly disengaged, small torque, long service life. Can be applied in the harsh conditions of conveying granular media. The structural principle is the offset size a of the centerline of the hemisphere (Fig. 2) and the valve stem centerline, and the offset size of the centerline of the valve seat. When fully opened, the ball and the valve seat are completely disengaged, and there is a certain clearance. The radius of gyration is divided into For the long radius and short radius, the tangent to the long-radius trajectory will form an angle θ with the valve seat sealing surface. When the valve is opened and closed, the hemisphere has a gradual disengagement from the valve seat surface (as shown in Figure 10). The core has been completely disengaged from the action of progressive extrusion, thereby reducing mechanical wear and scratches between the valve seat and the hemisphere during opening and closing and increasing the service life.
2.2 Seat (1) The valve seat (figure 3) adopts a floating design to reduce the processing difficulty and ensure that the centerline of the seat coincides with the center point of the hemispherical spherical surface, thereby improving the sealing performance. The valve seat and the valve body have a gap d. During the assembly, the hemispherical positioning can be used to automatically align the midline to ensure that the valve seat sealing surface and the hemispherical sphere are in full contact, thereby solving the leakage due to machining error and improving the performance of the ball valve. life.
(2) The seal between the valve seat and the valve body adopts a hard seal structure, which is suitable for high temperature and high pressure working conditions. Valve seat and valve body seal contact surface size c
The value is small, and the precision of their sealing surfaces is high. During assembly, the retainer is installed with an electric impact wrench. Not only is the retainer meshed with the valve body to prevent loosening, but also the valve seat frictionally rotates, conforming to the principle of mechanical vibration engagement and making the valve seat. Reliable sealing with valve body.
(3) The valve seat and the valve body, the valve seat and the hemisphere adopt two hard seals, so the valve can be used in high temperature and high pressure conditions.
2, 3 other components The overall use of modular design of the valve, the structure is simple, reliable, high versatility. The stem adopts an anti-outflow structure. The driving methods are diversified, and the connecting dimensions of the valve stem, the bracket and the actuator are in conformity with the ISO5211 standard, and can be directly combined with various specification implementing agencies. The commonly used driving methods include manual, pneumatic, hydraulic, gas-liquid linkage and electric, etc., thereby improving the performance of the double eccentric hemispherical valve.
3 Scope of use Double eccentric hemispherical valves are suitable for valves of various general industry requirements, such as water, sewage, wastewater, steam, gas, pulp and other media. If the sealing pair adopts Cr-Mn-Si cemented carbide and has the functions of fire resistance, explosion proof and anti-static, it is suitable for medium and high temperature medium requirements such as gas, coke oven gas, water gas and natural gas. If the sealing pair (hemisphere, valve seat) and valve body flow channel are treated with tungsten carbide special process, it has the advantages of high efficiency and energy saving, good wear resistance, reliable sealing performance, light operation, rapid opening and closing, long service life, etc. Industrial silicon industry is ideal for valves used on pipelines. Due to the instantaneous detachment of the hemisphere and the valve seat and the instantaneous compaction characteristics, it is suitable for the harsh working conditions that contain particles in the medium. It can be widely used in metallurgy, beneficiation, electricity and other production processes for blast furnace pulverized coal injection, pulverizing system and dust removal system. Various pipeline controls in the. In the process of instantaneous disengagement and instant compaction, the hemisphere and the valve seat have a squeezing effect to remove scale and sticky materials on the sealing surface, which ensures tight and reliable sealing. It is an ideal choice for valves with two-phase mixed fluid media in the process flow, such as easy to deposit sediment, crystallized solution slurry, slurry ash and other processes.
4 Conclusion At present, the double-equivalent hemispherical valve of a variety of specifications has been applied to various projects in different industries, the effect is good, and gradually expand the scope of use.
References [1] Lu Peiwen. Practical Valve Design Manual [M]. Beijing: Mechanical Industry Press, 1992.
[2] Wu Guoxi. Use and Maintenance of Regulators [M]. Beijing: Chemical Industry Press, 1992.
[3] Wang Wenbin. Mechanical Design Handbook, Third Edition [M]. Beijing: Mechanical Industry Press, 1992.
[4] Qu Jingxin, Wang Yuhong. Surface Engineering Handbook [M]. Beijing: Chemical Industry Press, 1992.
(Received date)