The pneumatic eccentric half ball valve is a valve device driven by a pneumatic actuator. It adopts flange or wafer connection and conforms to standards such as GB/T9113 and GB/T13927. Its core structure consists of an eccentric valve body, a ball, and a valve seat. Automatic centering and sealing are achieved through double eccentric rotation. The ball and valve seat are designed to be separated to eliminate wear of the sealing ring. The embedded non-metallic elastic valve seat or the welded alloy sealing surface can protect the metal substrate.
Principle and characteristics
The pneumatic eccentric half-ball valve operates by rotating a valve chain to open or close the valve. Ball valves are easy to operate, compact, and can be made in large diameters. They offer reliable sealing, a simple structure, and easy maintenance. The sealing surface and the ball are constantly in a closed state, making them less susceptible to erosion by the medium. They are widely used in various industries.
1. The structure utilizes an eccentric clamping principle, achieving braking, regulation, and closing through a transmission mechanism. The sealing pair is a metal-faced ring with a hard-faced contact seal. The double eccentric structure ensures that the valve core is located within the ball chamber when open, resulting in a large flow cross-section and preventing valve erosion. When closed, the valve core is also protected from erosion. During opening, the spherical surface of the valve core gradually moves along the valve seat, effectively removing scale buildup and achieving a reliable seal. It is particularly effective for mixed-flow transport where scale easily precipitates.
2. The valve's hemisphere is made of bimetal, with different alloys welded onto the base material. The valve seat also undergoes corresponding weld overlay and special treatment. The sealing surfaces are combined to create various types, including corrosion-resistant, wear-resistant, and high-strength options, to meet different application requirements.
3. Tight seal, achieving zero leakage when conveying harmful gases.
4. The valve core of the sealing pair has a compensation allowance; even after the valve wears down, a slight rotation when closed will still ensure a reliable seal, extending its service life. Furthermore, users can unscrew the clamping nut, adjust or replace the valve seat, and it will still be usable, avoiding the drawback of having to scrap the entire unit due to valve seal failure.
Performance Advantages
Low Torque, Long Lifespan
Eccentric structure reduces opening resistance, lowers actuator energy consumption, and extends valve lifespan.
Fast Response
Pneumatic drive offers fast response (typically ≤1 second), suitable for applications requiring frequent opening and closing.
Wear Resistance, Corrosion Resistance
Ball and seat materials can be stainless steel, hard alloy, etc., adaptable to high temperature, high pressure, and particulate media.
Bidirectional Sealing
Suitable for both forward and reverse flow conditions, reducing the number of valves and lowering system costs.
Automation Integration
Can be integrated with PLC, DCS, and other control systems for remote monitoring, regulation, and fault diagnosis.
Applications
Petrochemical Industry
Transporting crude oil, natural gas, chemical raw materials, etc., controlling pipeline flow and pressure.
Power Industry
Boiler feedwater, steam pipelines, cooling water systems, etc., regulating media flow.
Water Treatment
Sewage treatment, seawater desalination, water supply systems, controlling water flow and preventing backflow.
Metallurgical Mining
Transporting slurry, tailings, and high-temperature molten metal, adapting to harsh working conditions.
Paper Making, Pharmaceutical Manufacturing
Controlling the flow of viscous media such as slurries and pharmaceutical solutions to ensure process stability.