something about my research on ball valves

Ball valve, GB/T21465-2008 defined in terms of the valve for: on-off ball (a) by the valve stem drive around the stem and the axis of rotation movement for valve. Mainly used for the medium truncated or connect line, also can be used adjustment and control of fluid, including hard seal V type ball valves their V type ball core and surfacing carbide metal seated between strong shear force, is particularly applicable to contain fiber, micro solid makings, and other media. While many in the line through ball valve can not only the flexible control medium confluence, tap, and flow of switching, also can close any channel and make two other channels connected. This type valves in the pipe shall in general be installed horizontally.
Ball valve appeared in the 1950s, along with the rapid development of science and technology, production technology and product structure is the constant improvement, in a short span of 40 years, has quickly become one of the main valve class. In western industrialized countries, ball valves use are being continuously, the rise of the year in our country, ball valve is widely used in oil refining, long-distance pipelines, chemical industry, paper making, pharmacy, water conservancy, electric power, the municipal administration, the steel industry in the national economy, plays a very important role. Ball valve it has rotate it 90 degrees movement, cock body, circular for sphere through holes or passage through its axis. Ball valve is mainly used to do on lines cut, distribution and change flow direction of medium, it only need to use rotate it 90 degrees operation and small rotating torque can shuts rigor.
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