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Hard seal butterfly valve in low temperature working environment for its performance has higher requirements, which is due to low temperature environment, it will produce leakage, there are two factors were internal leakage and leakage.
Hard seal butterfly valve as a pipeline system to achieve on-off and flow control components, has been in oil, chemical, metallurgy, hydropower and many other fields have been widely used.
Hard sealing butterfly valve inner leakage reason is sealing at low temperature due to deformation of it, when the temperature dropped to the material phase change caused by volume changes, so that the original sealing surface of high precision grinding produces warpage caused by low-temperature sealing side.
Hard sealing butterfly valve new cone from the flat seal to seal. The valve seat is an oblique cone elliptic sealing surface, and a positive circular elastic sealing ring embedded on the butterfly plate is composed of a sealing pair. The sealing ring can float to the inner diameter of the butterfly plate groove. When the valve is closed, the first elastic sealing ring and sealing contact surface of the short axis of the ellipse, with the stem of the rotating seal ring gradually pushed inward, forcing the elastic ring again and the long axis oblique cone surface contact, resulting in elastic sealing oval ring and all contact with the sealing surface. Its seal is to rely on elastic ring deformation and achieve. When the valve opens, this elastic deformation disappears immediately, in the process of opening and closing basically no relative friction, so long service life.
Hard sealing butterfly valve leakage of the valve: one is the use of valves and pipe flange connection, the connection pad material, connecting bolts, and connections between the materials at low temperatures have not synchronized contraction and relaxation lead to leakage. So we connect the valve body and the pipeline from the flange connection to the welded structure, to avoid the low-temperature leakage. The second is the stem and filler leakage. General multi hard sealing butterfly valve number of valve packing using F4, because of its good self slip performance, friction coefficient (friction coefficient of steel to f=0.05 ~ 0.1), but also has a unique chemical stability, so widely used.
Low temperature working environment, the performance of the hard seal butterfly valve has higher requirements. Too Star valve summed up the low temperature environment, resulting in the situation of leakage and how to deal with, hoping to bring some help to customers.