• Triple Eccentric Metal Seated Butterfly Valves

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Triple Eccentric Metal Seated Butterfly Valves

  • Mar 31, 2023
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A triple eccentric metal seated butterfly valve is a regulating valve with a simple structure. Butterfly valves can be used to control various media such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media, which play the role of cutting and throttling the pipeline. The opening and closing part of the butterfly valve is a disc-shaped butterfly plate that rotates around its axis in the valve body to achieve the purpose of opening and closing or adjustment. The triple eccentric metal seated butterfly valve has a simple structure and fewer components. It is light. Such a structure and weight make it widely used in piping systems. 
 
Working principles of triple eccentric metal seated butterfly valves
The working principle of these valves is based on the triple eccentricity of the disc, shaft, and seat. The disc is positioned off-center from the shaft, which in turn is positioned off-center from the seat. This design ensures that the disc only contacts the seat at its final position, providing a tight seal. The metal seat of these valves provides excellent resistance to wear and tear, making them ideal for use in abrasive environments. Additionally, they can withstand high temperatures and pressures without compromising their sealing capabilities.
 
A triple eccentric metal-sealed butterfly valve has two eccentricities for the valve seat and valve plate, and the protruding surfaces of the valve plate and the valve seat are all inclined cone-shaped (the third eccentricity of the triple eccentricity). When the triple eccentric metal seated butterfly valve is closed, the valve plate is pushed forward due to eccentricity. There is no friction between the valve plate and the valve seat in the closing process, and the valve plate is directly pressed on the valve seat, which ensures the service life of the gate valve; in addition, the sealing ring of this valve has a certain degree of elasticity whether it is installed on the valve seat or the valve plate. There is a small gap between the boss in the elastic ring and the elastic ring, which can make the elastic ring slightly displaced. When the valve is closed, under the action of closing force, the elastomer sealing ring will automatically move to the position where the force is uniform; coupled with a small amount of deformation of the elastic ring, the force on the sealing ring at the valve seat is even and a good sealing state is achieved.
 
With the increase in the eccentric number of the valve plate and the thickening of the valve plate, the resistance of the liquid flowing through the triple eccentric butterfly valve increases; with the increase in the eccentric number of the butterfly valve, its performance also changes greatly. The triple eccentric metal seated butterfly valve can generate a great pressure drop and can be used as a regulating valve. The pressure drop of the liquid flowing through the valve increases with the increase in eccentricity. However, compared with other valves, the pressure drop of the triple eccentric butterfly valve is still small. As the eccentric number of butterfly valves changes, the sealing performance of the valve seat also changes. Triple eccentric butterfly valves have better seat sealing.
 
Advantages of triple eccentric butterfly valves
One of the main advantages is that they provide a tight seal with minimal leakage. This is due to the unique design that allows for metal-to-metal contact between the sealing surfaces. The triple offset also reduces wear and tear on the valve, which increases its lifespan. Another advantage is that they have a low torque requirement for operation. This means that less force is needed to open or close the valve, which reduces energy consumption and makes them easier to operate. Triple eccentric butterfly valves are also versatile and can be used in various applications such as high-pressure steam lines, cryogenic services, and corrosive environments.
 
Maintenance of triple eccentric butterfly valves
In daily use, the triple eccentric metal seated butterfly valve should be kept clean, so that it is not only smoother in use, but also more efficient. When a fault occurs during use, stop the operation in time; check and solve the problem properly. There are also certain requirements for the selection of the working environment. For example, the work of the triple eccentric metal seated butterfly valve will be affected in some high-temperature and high-pressure environments due to the structural material, so it is best not to work in these environments. Try to avoid scouring of the sealing surface when used, which will accelerate the wear of the triple eccentric metal seated butterfly valve. As long as the above points are maintained for the triple eccentric metal seated butterfly valve, its application will be relatively simple and its service life will be longer.
 
The sealing material of the triple eccentric metal seated butterfly valve is mainly rubber. However, the continuous use of the rubber elastic body in the butterfly valve will cause tearing, wear, aging, perforation and even falling, which will greatly affect the sealing of the butterfly valve. The thermal vulcanization process is adopted for repair, but it is difficult to meet the needs of on-site repair. In addition, special equipment should be used for repair, which consumes a lot of heat and electricity, and is time-consuming and labor-intensive. Nowadays, the method of polymer composite materials is gradually used to replace the traditional method, and the effect is better.