Three-piece ball valve installation and maintenance should note the following: 1. To leave the valve handle rotation position. Can not be used for throttling. 3 ball valve with transmission should be upright installation. Second, the working principle of eccentric ball valve is to make the valve, butterfly valve, filter, ball valve, steam trap, hydraulic control valve unblocked or blocked by the rotary valve. Ball valve switch is light, small size, can be made of large diameter, reliable sealing, simple structure, easy maintenance, sealing surface and the spherical surface is often closed, easy to be media erosion, widely used in various industries. Third, the insulation valve in the pipeline is mainly used to cut off, distribution and change the flow direction of the medium. Ball valve is widely used in recent years, a new type of valve, which has the following advantages: 1. Fluid resistance is small, the resistance coefficient and the same length of the pipe section. 2. Simple structure, small size, light weight. 3. Tight and reliable, the current ball valve sealing surface material widely used plastic, good sealing, vacuum system has also been widely used. 4. Easy to operate, quick opening and closing, as long as 90 ° rotation from full open to full close, easy to remote control. 5. Easy maintenance, ball valve structure is simple, the seals are generally active, demolition and replacement are more convenient. 6. In the fully open or fully closed, the ball and valve seat sealing surface and media isolation, the media will not cause erosion of the valve sealing surface. 7. Wide range of applications, the path from small to a few millimeters, up to a few meters, from high vacuum to high pressure can be applied. When the ball is rotated 90 degrees, the sphere should appear entirely at the entrance and exit, thus interrupting the flow. Insulated ball valve is a relatively new type of ball valve, which has its own unique structure of some advantages, such as friction switch, the seal is not easy to wear, opening and closing torque is small. This will reduce the size of the actuator fitted. With multi-turn electric actuator, the media can be adjusted and cut off. Widely used in petroleum, chemical, urban water supply and drainage requirements severely cut off the conditions.