Air Actuated Flanged Hard Seal Butterfly Valve is a butterfly valve driven by an air actuator featuring a hard seal structure, primarily used for fluid control. Its features include compact structure, easy operation, reliable performance, and simple maintenance.

Definition and Working Principle

Pneumatic flanged hard-seated butterfly valves operate by rotating the valve rod through an air-driven actuator, which in turn rotates the butterfly plate to open or close the valve. During rotation, the butterfly plate is sealed against the valve seat with a metal or hard material sealing ring, ensuring the fluid's seal integrity.

Application Scenario

Pneumatic flanged butterfly valves with hard seals are widely used in various industrial fields, particularly in the petrochemical, power, metallurgical, and papermaking industries. In the petrochemical sector, they are employed for controlling pipelines and equipment for the transportation and control of media such as crude oil, natural gas, and chemical raw materials. In the power industry, they are used for controlling equipment like boilers, steam turbines, and generators, including steam flow and cooling water flow. In the metallurgical industry, they are utilized for controlling processes such as smelting, casting, and rolling.

Structural Features

Three eccentric structure: The valve stem axis is offset by a dimension A from the butterfly seat sealing surface, and also offset by a dimension B from the valve body passage axis. The valve seat rotating axis forms an eccentric angle α with the valve body passage axis, creating a three eccentric structure. This structure allows the butterfly plate to immediately disengage from the valve seat upon opening, and only contact and clamp the seat upon closing, thereby reducing the possibility of wear and leakage.

Soft-hard stacked metal sealing structure: The butterfly plate seal ring utilizes a soft-hard stacked stainless steel plate and a flexible graphite plate for the sealing surface, offering both the advantages of metallic hard sealing and elastic sealing, suitable for various operating conditions.

Bidirectional Sealing: The sealing face cone angle is less than the friction angle of the sealing material, allowing for immediate self-locking upon closure and capable of withstanding certain reverse pressure impacts.

‌Fire-resistant Structure: The all-metal structure inherently possesses fire safety characteristics._

‌Wear-resistant: The valve body sealing surface is made of surfacing hard alloy or stainless steel, ensuring high strength, good hardness, and excellent wear resistance. It can undergo continuous opening and closing over 60,000 times without damage.‌