Butterfly development history, definition and specification parameters
1 development history
The United States invented the butterfly valve in 30s, in 50s introduced to Japan, until the 60s commonly used in Japan, but promoted in our country is after the 70s. generally the world butterfly valve above DN300 mm has been gradually replaced the gate valve. Butterfly valve has short opening and closing time compared with the gate valve, the operate torque is small, installation space is small and weight is light. Take DN1000 for example, butterfly valve is about 2T, while the gate valve is about 3.5T, and the valve is easy to combine with a variety of drive devices, with good durability and reliability.
The disadvantage of rubber sealing butterfly valve is when used for cutting, due to improper use will produce cavitation, so that rubber seat peels off, injury, etc. happened. To this end, now the international community has also developed metal sealing butterfly valve, cavitation area decreases, in recent years, China has also developed metal sealing butterfly valve, in recent years Japan has also developed resistance to cavitation erosion, low vibration, low noise comb-shaped butterfly valve.
Generally sealing seat life under normal circumstances, the rubber for 15 years -20 years, metal for 80 years -90 years. But how to choose the correct will according to working conditions requirements.
2 definition
Butterfly valve refers to the closed parts (disc or butterfly plate) is the disc, around the valve axis rotating to achieve the opening and closing valve, plays the role of cut off and throttle in the main pipe. Butterfly valve hoist part is a disc-shaped butterfly plate, around its own axis for rotation in the valve body, so as to achieve the purpose of hoisting or regulating. Butterfly valve from full-open to full-off is usually less than 90°, butterfly valves and butterfly stem do not have self-locking capabilities themselves, in order to butterfly plate positioning, should install the worm gear reducer on the stem. Using worm reducer, not only enable the butterfly plate with a self-locking ability, make the butterfly plate to stop at any position, and also can improve the valve operational performance.
3 specifications parameters
nominal pressure or pressure level：PN1.0-4.0MPa、ANSI CLASS 150-300LB、JIS10-20K
nominal diameter or caliber：DN40～2000
Connection mode: flange connection, wafer connections, butt welded connections and lug wafer connection
applicable temperature：-196℃～700℃
Drive mode: manual, worm gear drive, pneumatic, electric, hydraulic, Pneumatic, electro-hydraulic linkage
body material：HT200, WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8(304), CF3(304L), CF8M(316), CF3M(316L), Ti。
