Eccentric Butterfly Valves: Key Features and Applications

I. Technical features

(1) Structural designThe eccentric butterfly valve is mainly composed of a valve body, a valve disc, a valve stem and an actuator. Its unique eccentric design is the key feature. According to the number and position of eccentricity, it can be divided into single eccentric, double eccentric and triple eccentric butterfly valves. The valve stem axis of the single eccentric butterfly valve deviates from the center of the butterfly plate, which reduces the excessive extrusion between the upper and lower ends of the butterfly plate and the valve seat. The double eccentric butterfly valve is further improved on this basis. The valve stem axis deviates from both the center of the butterfly plate and the center of the body, so that the butterfly plate can quickly separate from the valve seat after the valve is opened, greatly eliminating the excessive extrusion and scratching between the butterfly plate and the valve seat, reducing the opening resistance and wear, and improving the life of the valve seat. On the basis of the double eccentric, the triple eccentric butterfly valve forms an angle α between the center line of the valve seat and the center line of the butterfly plate sealing surface. This design allows the butterfly plate to immediately separate from the valve seat when it is opened, reducing the friction and wear between the sealing surfaces, and improving the sealing performance and service life.

(2) Sealing performance
The eccentric butterfly valve has excellent sealing performance. The three-eccentric butterfly valve provides sealing pressure ratio through external torque, eliminating the reduction and disappearance of sealing pressure ratio between the two sealing surfaces of the sealing pair caused by aging, cold flow, elastic failure and other reasons of the elastic material of the elastic valve seat in the conventional butterfly valve. Its sealing test leakage is zero, and it can maintain a good sealing effect even under high pressure, high temperature and corrosive media. In addition, the sealing pair of the three-eccentric butterfly valve is in the shape of an inclined cone instead of a positive cone, which further optimizes the sealing performance.

(3) High temperature and corrosion resistance
Eccentric butterfly valves are suitable for the control of high temperature, high pressure and corrosive media. The high temperature resistance of the three-eccentric butterfly valve is particularly outstanding. Its metal sealing surface can remain stable in a high temperature environment and will not deform or fail due to temperature changes. At the same time, components such as the valve body and valve disc are usually made of corrosion-resistant materials, such as stainless steel, which can resist the erosion of various corrosive media.

(4) Operation performance
The eccentric butterfly valve has good operation performance. Its opening torque is relatively small and easy to operate. For example, the scratching of the double eccentric butterfly valve is greatly reduced, making the opening and closing of the valve smoother. The valve stem torque of the three-eccentric butterfly valve is directly transmitted to the sealing surface through the butterfly plate. There is almost no friction between the butterfly plate and the valve seat, which eliminates the common jumping phenomenon when opening ordinary butterfly valves and ensures the control performance of the valve within the low opening range.

(5) Wide range of applications
The eccentric butterfly valve can be adapted to angular stroke electric or pneumatic actuators and is suitable for various types of working conditions. It is widely used in chemical plants, environmental water treatment, lithium battery new materials and other fields. It has a compact structure, small size, light weight, and is easy to install and maintain. In addition, the eccentric butterfly valve can be installed vertically or horizontally, with good applicability.

II. Application fields

(1) Petrochemical industry
In the petrochemical industry, eccentric butterfly valves are used everywhere. In the process of oil refining, valves need to work under high temperature and high pressure. The three-eccentric butterfly valve has become the first choice in many production links due to its high temperature and pressure resistance. For example, in processes such as crude oil distillation and catalytic cracking, the three-eccentric butterfly valve can withstand high temperature and high pressure while ensuring sealing performance, ensuring the safety and stability of the production process. In addition, the rapid opening and closing characteristics of the three-eccentric butterfly valve are also a highlight in the petrochemical industry. It can quickly close the valve in an emergency to prevent accidents.

(2) Water treatment field
In the field of water treatment, eccentric butterfly valves also play an important role. In the process of sewage treatment, the valve needs to be opened and closed frequently to adjust the water flow. The three-eccentric butterfly valve has become a powerful assistant in sewage treatment due to its stability and sealing performance. Its good sealing performance can effectively prevent sewage leakage and avoid secondary pollution to the environment. In the purification process of drinking water, the use of three-eccentric butterfly valves is also crucial. Its sealing performance ensures the safety of water quality and protects people's health.

(3) Food processing industry
In the food processing industry, the hygiene standards are extremely high. The materials used in the three-eccentric butterfly valve are not only corrosion-resistant, but also easy to clean, which can meet the hygiene requirements in the food processing process. For example, in the beverage production process, from the transportation of raw materials to the packaging of finished products, the three-eccentric butterfly valve can ensure accurate control of the flow rate and help enterprises improve production efficiency. Its flow control ability provides great convenience for food processing and ensures the stability of product quality.

(4) Power industry
In the power industry, eccentric butterfly valves are widely used in cooling water systems, steam systems, etc. of power stations. Three-eccentric butterfly valves can withstand high temperature and high pressure, and have good sealing and adjustment performance, and can accurately control the flow and pressure of fluids. For example, in nuclear power plants, three-eccentric butterfly valves are used to control the flow of cooling water to ensure the safe operation of reactors. Its reliable performance and long life reduce maintenance costs and downtime, and improve the operating efficiency of power stations.

(5) Metallurgical industry
In the metallurgical industry, eccentric butterfly valves are used to control the flow of high temperature, high pressure and corrosive media. The high temperature resistance and metal sealing surface design of the three-eccentric butterfly valve enable it to work stably under harsh working conditions. For example, in blast furnace gas pipelines and oxygen pipelines in steel production, three-eccentric butterfly valves can effectively control the flow and pressure of gas to ensure the smooth progress of the production process. Its low friction resistance and fast opening and closing characteristics improve production efficiency and reduce energy consumption.