Manual ball valve is a kind of rotary type valve to realize opening and closing control by handle or worm gear transmission, widely used in petroleum, chemical industry, metallurgy, electric power, papermaking, water supply and drainage, food and other working conditions. The valve is suitable for water, oil, gas, steam, acid and alkali solutions and other media, with excellent sealing performance and corrosion resistance. Manual ball valve structure is simple, easy to operate, open and close quickly, only need to rotate 90 ° to realize the full open or full closed, small flow resistance, flow coefficient, to ensure smooth flow of pipeline media. Product advantages include compact structure, easy maintenance, strong pressure resistance, long service life, and can operate stably under the conditions of high pressure, large diameter and frequent operation. Manual ball valves can not only realize the precise cut-off and connection of the medium, but also realize simple flow adjustment according to the demand, it is the ideal valve choice for safety, economy and reliability in all kinds of fluid transportation and control system.