Inflatable Swimming Ring,Pool Ring Float,Inflatable Ring Pool,Blow Up Ring Pool ZHOUSHAN SKYTOP COMMODITY CO., LTD. , https://www.bodyboard.com.cn
Characteristics and application of double eccentric half ball valve performance structure
With the continuous development of the industry, the demand for ball valves especially for high temperature and high pressure harsh conditions is increasing. It is required that ball valves have higher wear resistance, erosion resistance, high temperature resistance and corrosion resistance. The traditional all-diameter ball valve ball center, seat after surfacing, spraying and other technology for surface hardening, but its service life, cost and performance still can not meet the requirements, such as industrial silicon, coal chemical industry, blast furnace gas, Gas and other harsh conditions. Double eccentric hemisphere valve is learned from the different structure of the ball valve, V-valve and rail ball valve, etc. The advantages of the development of new products. Ball valve with double eccentric seal structure, small wear, small torque, good sealing performance, long service life. Seat and hemisphere with a special hardening process, especially to meet the harsh conditions of wear-resistant, erosion-resistant, corrosion-resistant, high temperature requirements. 2, the structural characteristics of 2.1, hemisphere hemispherical semi-spherical double eccentric valve (Figure 1) double eccentric design, reliable sealing effect, instantaneous release, small torque, long service life. Can be used in the harsh conditions of the delivery of granular media. The structure principle is the hemisphere (Figure 2) midline and stem centerline offset size a, and seat center line offset size b, fully open ball and valve seat completely disconnected, and a certain gap, the radius of gyration is divided into Long radius and short radius, the tangent of the trajectory in the long radius will form a θ angle with the valve seat sealing surface, the valve opening and closing, the hemisphere relative to the valve seat surface has a gradual deviation (as shown in the opening 10 °, Core has been completely detached) and gradually squeeze the role, thereby reducing the valve seat opening and closing the hemisphere mechanical wear and abrasion, improve service life. Figure 1 double eccentric hemispherical valve Figure 2 sealing pair 1. Bottom cover 2. Retainer 3. Seat 4. Hemisphere 5. Body 6. Packing 7. Bracket 8. Shaft 1. Seat 2. Hemisphere 2.2, Valve Seat (1) The valve seat (Figure 3) uses a floating design to reduce the machining difficulty and ensure that the center line of the seat coincides with the center of the hemispherical sphere to improve the sealing performance. The valve seat and the valve gap d, the use of hemispherical positioning assembly can automatically find the center line to ensure that the valve seat sealing surface and the hemisphere spherical contact, to solve the machining accuracy error caused by the leakage and improve the performance of the ball valve and life. Figure 3 Seat 1. Retaining ring 2. Seat 3. Hemisphere 4. Valve body (2) The seal between the valve seat and the valve body is made of a hard seal, suitable for high temperature and high pressure conditions. Valve seat and valve body seal contact surface size c small, the sealing surface precision requirements are high, the assembly, the retainer with electric impact wrench installation, not only the retainer and valve body mesh to prevent loosening, but also seat friction rotation , In line with the principle of mechanical vibration meshing, so that the valve seat and the body reliably sealed. (3) seat and valve body and seat and hemisphere with two hard seal, so the valve can be used in high temperature and high pressure conditions. 2.3, other parts Valve modular design as a whole, simple structure, good reliability, high versatility. Stem with anti-spout structure. Diversified drive, stem, bracket and actuator connection size in line with ISO5211 standards, can be directly with a variety of regulatory agencies assembly. Commonly used driving methods are manual, pneumatic, hydraulic, gas-liquid linkage and electric, etc., thereby improving the performance of the double eccentric hemisphere valve. 3, the use of double eccentric semi-spherical valve for all types of general-purpose valves, such as water, sewage, wastewater, steam, gas, pulp and other media. If the seal pair uses Cr-Mn-Si cemented carbide and has fire, explosion and antistatic functions, it is suitable for medium and high temperature media such as gas, coke oven gas, water gas and natural gas. If the sealing pair (hemisphere, seat) and valve body flow through the tungsten carbide special process, with high efficiency and energy saving, wear resistance, reliable sealing performance, easy operation, quick opening and closing, long service life, etc. is Industrial silicon pipe industry with the ideal valve. Because of its hemisphere and valve instantaneous detachment and instant compression characteristics, suitable for medium containing particles harsh conditions, can be widely used in metallurgy, mineral processing, power and other production processes blast furnace pulverized coal injection, pulverizing system and dust removal system In a variety of pipeline control. In the moment of separation and instantaneous compression process, the hemisphere and seat squeeze can remove the sealing surface of the scale and adhesions, to ensure tight and reliable seal. It is an ideal choice for two-phase fluid medium valve used in conveying process such as sedimentation and scaling, crystallization of solution slurry, slurry ash and other processes. 4 Conclusion At present, a variety of dual-eccentricity semi-spherical valve products have been applied in various projects in different industries, the effect is good, and gradually expand the scope of use. This article Keywords: ball valve