Pneumatic Triple‑Offset Lug‑Type Butterfly Valve ANSI Class

Pneumatic Triple‑Offset Lug‑Type Butterfly Valve is a high‑performance butterfly valve driven by a pneumatic actuator, featuring lug‑type end connections and triple‑offset geometry. It is mainly applied for media shut‑off and flow control in industrial piping systems.

Adopting a triple‑offset metal‑seated design, the valve optimizes the eccentric positions of the valve stem axis and sealing surfaces. This enables nearly friction‑free or low‑friction movement between the disc and seat during opening and closing, which effectively reduces seal‑face wear and operating torque. When closing the valve, the disc approaches the seat gradually via eccentric rotation, and forms reliable metal‑to‑metal sealing at the final closing stage.

Operating Principle of Pneumatic Triple‑Offset Lug‑Type Butterfly Valve：
Opening Stroke: Upon receiving an opening signal, compressed air enters the pneumatic actuator to generate rotational torque, which drives the valve stem and disc to rotate. Thanks to the triple‑offset design, the disc quickly lifts away from the seat during opening, minimizing friction and wear between sealing surfaces. When the disc rotates to a position nearly parallel to the pipeline flow‑path, the valve reaches full‑open position, allowing unobstructed media flow.

Closing Stroke: When the control system sends a closing signal, the pneumatic actuator operates in reverse to gradually close the disc. As the disc approaches the closed position, it moves toward the seat following the triple‑offset sealing trajectory. At the final stage of closing, mechanical wedging is generated between the disc and seat to achieve reliable metal‑to‑metal hard sealing, effectively shutting off pipeline media.

Automatic Control: Either double‑acting or spring‑return single‑acting pneumatic actuators can be selected according to actual service conditions. Solenoid valves control actuator movement to realize automatic valve opening and closing. Limit switches provide feedback of valve position status. A valve positioner adjusts the disc opening degree per control signals to achieve automatic flow control within a certain range.