How to identify the high quality stainless steel by the pneumatic valve

how to identify the high quality stainless steel by the pneumatic valve
stainless steel by the pneumatic valve opening and closing is plug piece of pneumatic valve, sealing surfaces appear flat or cone, pneumatic disc make linear movement along the centerline of the fluid. Pneumatic valve stem form of exercise, lifting lever ( Pneumatic valve rod, does not lift the handwheel, also have lift rotating lever ( The handwheel with pneumatic valve rod rotating lifting, nut in pneumatic valve body. Stainless steel by pneumatic valve used throughout opened only close, not allowed to adjust and throttling.
stainless steel by the pneumatic valve belong to mandatory sealed pneumatic valve, in pneumatic valve is closed, so must to pressure pneumatic disc, to force a sealing surface does not leak. When medium by pneumatic disc below 6 into the pneumatic valve, operating force required to overcome resistance, is pneumatic stem and packing of the friction force and the thrust produced by medium pressure, close the pneumatic valve force than the pneumatic valves open force is big, so the larger the diameter of the pneumatic valve stem, or pneumatic stem top bending failure happens. In recent years, from the seal of pneumatic valves, stainless steel as the flow direction of medium of the pneumatic valve is replaced by pneumatic disc into the pneumatic valve cavity above, under the effect of medium pressure at this moment, close the pneumatic valve is small, the force and the great strength of pneumatic valve, pneumatic valve stem diameter can be reduced accordingly. At the same time, in the role of media, this kind of pneumatic valve is tight. Pneumatic valve in China 'three for' regulation, the flow of stainless steel by the pneumatic valve, shall be applied.
stainless steel as the pneumatic valve opens, the opening of pneumatic disc height, for the nominal diameter % ~ %, traffic has reached maximum, said the pneumatic valve to full open position. So by the pneumatic valve fully open position, stainless steel shall be determined by pneumatic disc trip.