The valve body and valve cover are in direct contact with the medium and withstand the pressure and corrosion of the medium. The materials used must meet mechanical properties as well as good cold and hot working process under the specified medium temperature and pressure. Due to the complex shape of the valve body and bonnet, so the casting molding method. In view of the emergency shut-off valve is installed on three types of pressure vessels, and the media is highly toxic and corrosive, valve casting quality is particularly important. In recent years, a large number of precision casting process applications, so the nominal size DN ≤ 50mm, the valve body and bonnet with precision cast LCB steel castings or 25,35 steel. Due to the emergency shut-off valve for storage of liquid chlorine medium device, the sealing surface material must be resistant to liquid chlorine corrosion and erosion. In addition, due to the sealing force of this type of valve is mainly medium pressure and spring force, can not add a great sealing force, so the choice of sealing PTFE and chrome-nickel stainless steel composite structure. PTFE corrosion resistance, low friction coefficient, chemical stability, suitable for use in liquid chlorine medium. Chromium-nickel stainless steel (commonly used grades 0Cr18Ni9, 0Cr18Ni9Ti, 1Cr18Ni9 and 1Cr18Ni9Ti) have good corrosion resistance, low temperature resistance and erosion resistance, relatively suitable for liquid chlorine medium, the temperature range can be within the - 196 ~ 600 ℃ . The linear expansion coefficient of the sealing surface and the body material should be close, and the structure of the sealing ring is also important to avoid loosening under the additional stress. The spring is the key part of the emergency shut-off valve, the quality of the large spring affects the sealing performance and service life of the valve, the quality of the small spring affects the over-current shut-off performance, and the spring quality largely depends on the spring material. Relatively adapted emergency cut-off valve spring material for 1Cr18Ni9 austenitic stainless steel, as long as properly handled, both corrosion of liquid chlorine, but also to ensure the quality of the spring. Pivot valves and over-flow valve and other internal parts of the valve body is directly in contact with the media parts, if these parts are subject to corrosion of the media, it will directly affect the life of the emergency shut-off valve, serious safety accidents will occur. Therefore, the parts in direct contact with the medium selected austenitic stainless steel, then according to different requirements, determine the different heat treatment methods. The O-ring used on the emergency shut-off valve can prevent leakage of the medium and resist the corrosion of liquid chlorine. The outer layer is polytetrafluoroethylene ring and the inner layer is silicone rubber ring. The adhesive layer is suitable for working temperature and resistance Ageing. O-ring coated with anti-oxidizing medium corrosion is an excellent seal components. Search Keyword: More Valve Product Information
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