Double offset butterfly valves because of its stem axis deviation from center line butterfly plate and valve body, and named, in the open when the butterfly disc can quickly out of the seat, and reduces the open torque, the maximum double offset butterfly valve can adopt resilient sealing structure to metal seal structure, the metal seal structure can improve the use of under high temperature conditions, so the double offset , also known as high performance butterfly valve; Triple offset butterfly valve, because on the basis of the double offset butterfly disc the sealing surface of the conical cylinder axis and axis deviation from ontology, through position change to torsion, solves the problem of high temperature and high pressure, at the same time through the seat contact area of the structure of the pressure to achieve sealing effect, make the medium pressure, the greater the pressure is, the greater the contact area, solved the difficult problem of metal seal butterfly valve zero leakage.
According to the structural form, butterfly valve can be divided into Triple offset butterfly valve, high-performance butterfly valve, metal seated butterfly valve and double offset butterfly valve. The structural difference of butterfly mainly lies in whether the stem axis, disc center, body center is in the same position or eccentric position.
The drive mode of the butterfly valve can be divided into manual, pneumatic and electric, gear operated and motorized. The choice of operation mode also depends on the clients’ requirements and the limitation of operating conditions.
The temperature, pressure and type of medium affect the valve body and interior material of the butterfly valve. Body materials of ZECO butterfly valves include, but are not limited to stainless steel, wcb, carbon steel, forged and cryogenic.
Butterfly valves are usually larger in size because they are easier to install on larger piping to save space. ZECO international standard valve company manufactures the butterfly valve of smallest 2 inches, 3 inches, 4 inches, 6 inches, 8 inches, 12 inch and maximum 96 inches.
Butterfly valve is operated through the 90-degree rotation of the butterfly plate and can be used in the pipeline for regulating and stopping media. The disc of the butterfly valve is perpendicular to the direction of medium flow. The user can adjust the flow of the medium by opening or closing the butterfly plate.
Butterfly valves are widely used in various industrial fields because of their small size, low cost, and convenient installation. Butterfly valves are divided into three categories, the center line butterfly valve because its stem does not deviate from the center and named, With a rubber seat and no stem packing, the seal is achieved by matching butterfly plate and rubber seat，usually for the soft seal structure for low-pressure water treatment industry and Marine water system.