Manual valve sealing advantages
All manual main valve seat ring material is polytetrafluoroethylene (PTFE), it is almost all chemical substances are inert, and has a low coefficient of friction, stable performance, easy to aging, temperature and sealing for a wide range excellent performance of the integrated features. However, the physical properties of PTFE, including a higher coefficient of expansion of the cold sensitivity and poor thermal conductivity, required seating must be designed around these features. Seat seal plastic material also includes a filled PTFE, nylon, and many other materials. However, when the sealing material hardens, sealing reliability must be destroyed, especially in the case of low-voltage differential. In addition, like Dingqing rubber, synthetic rubber such seat material can also be used, but it applies to the media and the use of drugs is limited temperature range. In addition, if the media is not lubricated, easy to get stuck using synthetic rubber sphere. In order to meet the high temperature, high pressure, strong erosion, long life and other requirements for use in industrial applications, the last decade, metal seated ball valves have been greatly developed. Especially in the industrialized countries, such as USA, Italy, Germany, Spain, the Netherlands, etc., on the structure of continuous improvement ball appears buried fully welded ball valve body, valve lift, the valve in the long-distance pipelines, oil refining equipment, etc. industrial applications more widely, the emergence of large diameter (3050mm), high pressure (70MPa), wide temperature range (-196 to 815 degrees) of the ball, allowing the ball valve technology has reached a whole new level.