‌Core Working Principles of Flue Gas Butterfly Valves:

1. ‌Rotational Control Mechanism:‌
   The disc rotates 90° to achieve rapid opening/closing and flow regulation. The bidirectional flow design accommodates both forward and reverse media directions.
2. ‌Actuation & Positioning:‌
   The electric actuator precisely controls the rotation angle via motor drive and gear reduction, ensuring responsive operation. Internal limit switches guarantee accurate positioning.
3. ‌High-Temperature Sealing Optimization:‌
   Planar sealing between the disc and seat—combined with elastic material seats—automatically adjusts contact pressure, thus ensuring reliable sealing integrity in high-temperature flue gas environments (e.g., desulfurization systems).

4. Introduction to Flue Gas Butterfly Valves

   Flue gas butterfly valves are specialized control valves designed for high-temperature, high-pressure, and corrosive gas media (e.g., flue gas, dust, hot air). Widely used in industrial ventilation, environmental dust removal, and energy systems, they are systematically introduced below across five aspects: core definition, working principles, structural types, key features, and typical applications.

5. Definition & Overview‌

   Flue gas butterfly valves utilize a circular disc structure to regulate, divert, merge, or switch media flow via rotational motion. They are primarily deployed in harsh environments such as high-temperature flues and desulfurization systems. Core functions include ‌flow regulation‌, ‌pressure control‌, and ‌media isolation‌, offering advantages of ‌low flow resistance‌, ‌rapid actuation‌, and ‌ease of maintenance‌.

6. ‌Working Principles‌

   The valve operates via an external drive (e.g., manual lever, electric/pneumatic actuator) rotating the valve stem to move the disc between 0° (closed) and 90° (open):

   • ‌Open/Close Control‌:
     • Parallel to pipeline axis: ‌Full open‌ (minimal flow resistance).
     • Perpendicular to axis: ‌Fully sealed‌ (zero media leakage).
   • ‌Sealing Mechanism‌:
     • Disc and seat form a sealing interface via ‌planar sealing‌ or elastic materials (e.g., EPDM rubber).
     • In closed position, the seat deforms under compression to generate sealing pressure (leakage class up to ‌ANSI Class VI‌).
   • ‌Actuation Modes‌:
     • ‌Manual‌: Adjust opening via handwheel scale.
     • ‌Electric/Pneumatic‌: Actuator receives 4–20mA signals for precise flow control and automated operation.

       
       

       
       

     • Structure & Classifications‌

       Classified by eccentricity design:

       • ‌Centerline Type‌:
         Stem aligns with disc center; bidirectional sealing; ultra-low flow resistance; ideal for low-pressure, high-flow systems (e.g., ventilation ducts).
       • ‌Eccentric Type‌:
         • Single/Double/Triple-offset designs reduce friction and enhance seal durability under high pressure/temperature (e.g., triple-offset suits extreme temperatures ≤650°C).
       • ‌Material Selection‌:
         • Body: Carbon steel/stainless steel.
         • Disc/Seal Ring: Corrosion/wear-resistant alloys (304H stainless steel, duplex steel, Hastelloy®).
         • Seat: Tungsten carbide overlay for abrasion resistance.
       • ‌Innovative Designs‌:
         • ‌Four-bar linkage mechanism‌ (drive arm, driven arm, etc.) vertically lifts the disc away from the seat during operation, minimizing friction and distributing pressure evenly to extend seal life.

1. Specification: