1. Definition and core structure
A double flange butterfly valve refers to a butterfly valve with flange structures at both ends of the valve body, which is directly connected to the pipeline flange through bolts to achieve fluid control. Its core structure includes the valve body, butterfly plate, valve stem and flange assembly. The butterfly plate rotates around the valve stem by 0°~90° to complete opening and closing, and is mainly used to cut off or adjust the flow of pipeline media. Compared with the wafer-type butterfly valve, the double flange butterfly valve enhances the stability and sealing of the connection through flange docking.
2. Key technical characteristics
Flange connection design
The flanges at both ends of the valve body are rigidly connected to the pipeline flange through bolts and nuts. They can withstand higher pressures (such as PN16 and above) during installation, and the removal of one-side flanges during disassembly will not affect the operation of the pipeline on the other side;
The flange surface usually adopts a full-plane or convex sealing form, suitable for rubber gaskets or metal spiral wound gaskets to ensure the sealing reliability under medium and high pressure conditions.
Drive and sealing performance
Supports manual worm gear, pneumatic or electric actuator drive, low operating torque and fast response speed;
The sealing structure can choose soft seal (such as EPDM, PTFE) or hard seal (stainless steel cladding carbide) to meet the needs of different media (such as water, steam, corrosive liquids).
3. Typical application scenarios
High-pressure fluid system: such as petrochemical pipelines, thermal steam pipelines, its flange structure can effectively cope with pulse pressure and temperature fluctuations;
Occasions where frequent disassembly is required: During maintenance, only one-side bolts need to be removed to avoid the valve from falling off as a whole, which is suitable for industrial scenarios with frequent equipment maintenance;
Large pipe diameter control: DN100 and above are commonly used in data center air conditioning water systems and municipal water supply and drainage projects. Flange connection ensures structural stability under large flow.
4. Comparison of the advantages of wafer-type butterfly valves
Vibration resistance: The flange connection disperses the pipeline stress and reduces the risk of bolt loosening or leakage caused by vibration;
Installation tolerance: The requirements for pipeline flange hole alignment are lower, and the construction adaptability is stronger;
Sealing surface maintenance: When the single-side seal fails, it can be partially repaired without replacing the valve as a whole, reducing operation and maintenance costs.
