Structural features

1. Valve body structure: Large diameter adaptation and flow optimization
The valve body is formed by integral casting or welding (mostly made of ductile iron, carbon steel or stainless steel), and the wall thickness is designed according to the pipeline pressure grade (such as PN10/PN16) to ensure the pressure-bearing strength under the large diameter of DN1200 and avoid deformation. ​
The flow channel adopts a straight-through streamlined design, with the inner diameter matching the nominal diameter of the pipe, reducing the flow resistance of the medium (such as water, sewage, gas), lowering energy consumption, and is suitable for high-flow transportation scenarios (such as municipal water supply and drainage, industrial circulating water systems). ​
2. Butterfly plate and seal: Double guarantee of sealing performance
Butterfly plate: It adopts a double eccentric or triple eccentric structure (triple eccentric is commonly used for large-diameter valves), and the material corresponds to the valve body (for example, stainless steel butterfly plates are suitable for corrosive media). The thickness has been mechanically calculated to ensure that it is not easy to deform during opening and closing. The edge conforms to the sealing surface, and zero leakage or low leakage can be achieved when closed (conforming to the sealing standards of GB/T 13927 or API 598). ​
Sealing surface: It is divided into two types: soft sealing (nitrile rubber, ethylene propylene diene monomer rubber) and hard sealing (stainless steel surfacing, ceramic coating). Due to its large diameter, DN1200 mostly adopts the "O-ring butterfly plate extrusion" method for soft sealing, while hard sealing ensures a good fit through precise processing, making it suitable for different temperature (-20℃ to 400℃) and medium requirements. ​
3. Valve Stem and drive: Stable transmission and convenient operation
Valve stem: It adopts a thickened solid shaft (mostly made of 2Cr13 or 304 stainless steel), with the top connected to the drive device and the bottom fixed through bearings or shaft sleeves to prevent the valve stem from bending caused by the self-weight of the DN1200 butterfly plate. The surface is treated with chromium plating or nitriding to enhance wear resistance and rust prevention. ​
Drive adaptation: Supports three drive methods: manual (worm gear and worm), electric, and pneumatic. In large-diameter scenarios, electric/pneumatic drive is preferred. It is equipped with a reduction mechanism to achieve slow opening and closing (to prevent water hammer impact), and can be remotely controlled, making it compatible with automated pipeline systems. ​
4. Flange connection: Standardized installation and sealing performance
The flange connection adopts the national standard (GB/T 9119) or the American standard (ANSI B16.5). The flange sealing surface is raised face (RF) or concave-convex face (MFM). The number and distribution of bolt holes comply with the DN1200 size standard, which is convenient for precise connection with the pipeline. ​
When installing, it is evenly tightened with bolts to ensure a tight fit between the valve body flange and the pipe flange. Combined with sealing gaskets (such as rubber gaskets or graphite gaskets), the overall sealing performance is further enhanced, making it suitable for high-pressure working conditions of large-diameter pipes. ​
5. Auxiliary structure: Adapted to the requirements of large-diameter usage
Some models are equipped with thrust bearings or guide sleeves to reduce the friction when the valve stem rotates and extend its service life. ​
Both ends of the valve body can be reserved with drainage holes or pressure detection interfaces, which is convenient for checking the residual medium or monitoring the pipeline pressure during daily maintenance, and is suitable for the maintenance requirements of DN1200 valves after long-term operation.