Flange seal butterfly structure size is short, small size, light weight, easy operation using axle structure, the disc using truss structure, high strength, flow area, flow resistance, energy saving eccentric structure, closed with a The more a function more tightly shut, sealing performance, reliable, open and close after the sealing surface to ensure complete disengagement, to ensure the sealing surface from damage sealing surface made of stainless steel production, corrosion resistant, high temperature, long life characteristics with two-way sealing function install the unrestricted flow of the medium (if only control one-way media should be given priority in favor of the direction of the seal is installed) are not affected by spatial units can be installed underground pipe network butterfly for horizontal installation in any direction, nationally unique way synchronization display mechanism can be observed from the operating direction of the valve is closed or open. Required the installation location, users also can choose to display the country unique way synchronization mechanism can be observed simultaneously from the operating direction of the valve closed or open state side or main performance parameters of the nominal diameter DN (mm) 50 ~ 2000 Nominal pressure PN (MPa ) 0.25 0.6 1.0 1.6 2.5 4.0 Test pressure Ps (MPa) 0.9 1.5 2.4 0.375 strength test 3.75 6.0 sealing test O.275 0.66 1.1 1.76 2.75 4.4 gas seal test O. 5 ~ 0.8 MPa Suitable medium water, oil, steam, gas, acid, alkali and other applicable temperature a 40 ℃ ~ 5 70 ℃ main parts Material Name Material Body carbon steel, stainless steel, chrome molybdenum vanadium steel valve plate steel, stainless steel, chrome molybdenum vanadium steel stem 2Cr13 stainless steel, chrome molybdenum vanadium steel ring stainless steel, PTFE, hard and soft seat stainless steel metal sheets stacked, piled Stellite alloy filler such as flexible graphite, PTFE Ethylene