Basic Structure
- Valve Body: Usually made of materials such as ductile iron, carbon steel, and stainless steel (e.g., 304, 316). The blue valve body part in the picture may be carbon steel with anti-corrosion coating. This material is strong and durable, capable of withstanding high pressure and harsh working environments.
- Butterfly Disc: Often uses stainless steel, alloy materials, etc., which have good strength and corrosion resistance. The triple-eccentric design of the butterfly disc is a key feature of this valve. It rotates driven by the valve stem to open or close the valve.
- Valve Seat: Common materials include stainless steel, cemented carbide, rubber, etc. Metal valve seats are suitable for harsh working conditions such as high temperature, high pressure, and strong corrosion. Rubber valve seats have good sealing performance and are suitable for general fluid control.
- Pneumatic Actuator: The black and silver-gray part at the top in the picture is the pneumatic actuator, which is driven by an air source (compressed air) to control the rotation of the butterfly disc. There are two types of actuators: double-acting and single-acting (spring return). The single-acting actuator can automatically reset by relying on the spring when there is no air supply, realizing the emergency closing or opening of the valve and ensuring system safety.
Working Principle
The three eccentricities of the triple-eccentric butterfly valve are: radial eccentricity, axial eccentricity, and angular eccentricity. This unique design makes the valve seat and the butterfly disc gradually separate from or contact each other during the opening and closing process, reducing friction and wear. At the same time, it improves the sealing performance and can achieve zero leakage. In the closed state, the butterfly disc fits tightly with the valve seat to block the flow of the medium; when compressed air is introduced, the pneumatic actuator drives the valve stem and rotates the butterfly disc to open the valve, allowing the medium to pass through.
Performance characteristics
- High Sealing Performance: The triple-eccentric structure makes the sealing specific pressure between the butterfly disc and the valve seat uniform when the valve is closed, achieving a very high sealing level, even zero leakage. It is suitable for occasions with strict sealing requirements, such as gas transmission and chemical fluid control.
- Wear Resistance: There is almost no friction between the butterfly disc and the valve seat during the opening and closing process, which prolongs the service life of the valve, especially suitable for working conditions with media containing particles and impurities.
- Wide Application Range: It can adapt to various harsh working environments such as high temperature, high pressure, low temperature, and strong corrosion. The general working temperature range is about -40ºC - 450ºC, and the working pressure can reach PN16 - PN100 (specifically according to product specifications).
- Quick Opening and Closing: The pneumatic actuator has a fast response speed, which can quickly open and close the valve to meet the needs of automatic control.
Application Fields
- Petrochemical Industry: Used for the transportation of petroleum, chemical raw materials and products, and controlling the flow of various corrosive, flammable, and explosive media.
- Power Industry: In the steam-water system of thermal power plants and the gas transmission system of gas-fired power plants, it plays a role in cutting off or regulating the flow of media.
- Metallurgical Industry: Suitable for the control of blast furnace gas, oxygen, nitrogen, and other media, ensuring the safety and stability of the metallurgical production process.
- Urban Gas: As a key equipment in the urban gas transmission and distribution system, it ensures the safe transmission and distribution of gas.
Maintenance
- Regular Inspection: Check whether the air source pressure of the pneumatic actuator is normal, whether the sealing performance of the valve is good, and whether there is any leakage.
- Cleaning: Regularly clean the inside of the valve to prevent the accumulation of impurities and particles from affecting the normal operation and sealing performance of the valve.
- Lubrication: Regularly lubricate the moving parts such as the valve stem to reduce friction and ensure the flexible rotation of the valve.
- Pneumatic Actuator Maintenance: Check whether the seals of the actuator are aged or damaged, and replace them in time; check the working status of accessories such as solenoid valves and filters.
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