Polycrystalline silicon special rotary ball valve

多晶硅专用旋球阀is a high-performance valve designed for harsh working conditions in the production process of polycrystalline silicon, such as strong corrosion, high wear, and temperature fluctuations. The core technical features and application points are as follows:
1、 Core structure and working principle
Bidirectional hard seal design
Adopting an eccentric hemispherical valve structure, the sealing surface of the valve core is a cubic surface, forming a self centering compensation mechanism with the conical valve seat, which can automatically correct installation deviations and compensate for wear.
It can tightly seal under both forward and reverse pressure, and the sealing ratio increases with the increase of medium pressure, achieving near zero leakage (leakage level reaches ANSI VI level).
Wear resistant strengthening process
Surface treatment: The sealing surfaces of the valve seat, sphere, and stem are sprayed with nickel based hard alloy (such as tungsten carbide), with a surface hardness of ≥ HRC65. The coating thickness is ≥ 0.8mm for hot spraying (adhesion of 200MPa) and ≥ 0.2mm for cold spraying (adhesion of 70MPa). The hardness under extreme working conditions can reach HRC70.
Material upgrade: The main body is made of stainless steel or carbon steel substrate, and the valve seat can be made of high-performance engineering plastics such as DEVLON and PEEK. The ball body is enhanced in wear resistance by hot-dip nickel phosphorus plating.
2、 Performance advantages
Resistant to extreme working conditions: Suitable for temperature range of -70 ℃ to 425 ℃ (high temperature type), pressure rating covers PN10-PN25.
Low torque operation: Butterfly lightweight design reduces opening and closing torque (manual torque ≤ 200N · m), optional pneumatic actuator (thrust ≥ 5000N) for automated control.
Compact structure: Combining the sealing performance of ball valves with the volume advantage of butterfly valves, the height is reduced by more than 30% compared to traditional ball valves, reducing installation space occupation.
3、 Key Applications in Polycrystalline Silicon Production
Core process segment adaptation
Process functional requirements, valve function
Cold hydrogenation high-temperature chlorosilane medium control, wear-resistant cutoff and flow regulation
Recovery of high-pressure gas containing solid particles from the tail gas of the reduction furnace with bidirectional sealing to prevent backflow
Accurate control and zero leakage regulation of corrosive fluids in distillation systems
Response to special working conditions
Wear resistant and erosion resistant: suitable for slurry media containing silicon powder and catalysts, to avoid valve seat erosion failure.
Temperature alternation: Design a reinforced valve stem with a safety factor of ≥ 1.5 (straightness of 0.5/1000mm) to resist thermal stress deformation.
4、 Mainstream models and technological evolution of polycrystalline silicon specialized ball valves
Typical models: GWXDF bidirectional hard seal rotary ball valve, XQF polycrystalline silicon special series, nominal diameter DN50-DN2200.
Technological iteration: Intelligent positioning pneumatic regulation type will be launched after 2023 to achieve precise flow control; The friction coefficient of the sealing pair is reduced to below 0.08, extending the service life to over 100000 opening and closing cycles.
Selection suggestion: Prioritize suppliers with ISO9001 certification and compliance with GB/T 21385 standards. Before installation, clean the pipeline and verify the flatness of the flange mating surface to avoid impurities affecting the sealing performance.