Triple Eccentric Butterfly Valve is widely used in various fields because of its good sealing performance. The sealing forms of tri-eccentric butterfly valve can be divided into three types: soft seal, hard seal and combination seal. Below Beijing Ruitou Xiaobian to take you together to understand the advantages and disadvantages of three types of eccentric butterfly valve seal.
Soft seal

The seals are rubber products. After the valve is closed, the valve plate contacts with the seals, and the seals are compressed and deformed to act as seals. In metallurgical enterprises, the service life of soft seals is not long because of the high temperature, large impurity particles and bad working conditions of rubber products.

Hard seal
The sealing surface is metal surface, the sealing surface on the valve plate and the sealing surface on the valve seat should be refined to ensure a certain degree of smoothness and hardness, and the wear-resistant material should be surfaced on the sealing surface. Hard sealing surface can be regarded as the surface of many contour bees. Under the action of sealing force, small concave and convex deformation occurs on the contact surface. When the force between the contact surfaces is small, the contact contour peak is elastic deformation, and plastic deformation occurs as a greater force. Therefore, in order to achieve reliable sealing, the specific pressure must be increased to make the surface plastic deformation. However, the driving force of the valve is certain, which can only improve the surface processing accuracy, overcome the roughness and ensure the sealing. Therefore, the requirement of processing precision and installation precision of hard seals is high, and they are mostly used in high temperature and wear occasions. However, the hard seal has a large impact when the valve is closed, and the medium particles are large, and the sealing performance is poor for a long time.
Soft and Hard Combined Seal
A typical one is to use stainless steel elastic ring seat seals instead of rubber seals. Sealing is a metal elastic seal between the valve plate polished by surfacing wear-resistant material and the stainless steel elastic seal ring installed in the valve body groove. The valve plate is an elliptical valve plate with an asymmetric arc sealing surface. The stainless steel seal ring adopts special section shape. Select appropriate elastic force to form a certain specific pressure with the contact surface of butterfly valve plate after closing. The structure is suitable for high temperature, high pressure and difficult to disassemble and assemble. It has long service life and needs no repair. This kind of seal is better than soft seal and hard seal.
Three sealing forms of Triple Eccentric Butterfly Valve, soft seal because of its rubber products, in high temperature environment, the service life is shorter; hard seal is mostly used in high temperature environment, but because of its large impact when closed, medium particles are large, many, poor sealing. At present, the most common sealing form of Triple Eccentric Butterfly Valve is soft combination seal. This sealing structure has good sealing effect in high temperature, high pressure and long river which is not easy to disassemble and assemble.