The hard-sealed butterfly valve we usually see is basically a triple eccentric butterfly valve. The so-called "triple eccentricity" refers to the offset of the relative position of the valve shaft and the valve plate in the valve. Ordinary butterfly valves are all eccentric, that is, the center line of the valve shaft and the center line of the sealing surface (the center line of the valve plate) deviate; the high-performance double eccentric butterfly valve adds an eccentric, that is, the center line of the valve shaft and the center line of the valve (the center line of the pipeline). ) deviation; the purpose of double eccentricity is that when the valve is opened, the valve plate and the sealing pair are separated from each other, thereby reducing friction.
The triple eccentric butterfly valve adds a unique eccentric-inclined cone on the basis of the above double eccentricity, that is, the offset of the valve plate (the sealing surface is inclined at an angle to the vertical plane of the pipeline). In this way, within the 90° stroke range of the valve, the sealing pairs are completely disengaged, and friction is completely eliminated; at the same time, when the valve is closed, when the sealing pair is gradually closed, a "wedge effect" is generated, and the tightest shut-off is achieved with the smallest torque. .
The triple eccentric butterfly valve is a metal seal, so it is also called a hard seal butterfly valve. The so-called "metal seal" means that the valve seat and the sealing ring are made of high-quality alloys that are wear-resistant, corrosion-resistant and high-temperature resistant. At the same time, in order to avoid the sealing ring and the valve seat Hard to touch, the sealing pairs are designed to be in flexible contact, that is, to form an "elastic metal seal" to ensure tight closing and frictionless opening. With the "triple eccentric" structure, supplemented by "elastic metal seals", such valves are easy to operate, durable and well sealed.
The triple eccentric metal-sealed butterfly valve can be used in heating pipelines, but it is mostly used in the main line and main branch of the heating system. It can be used on pipes with a diameter of DN300 and above.
