The three-piece ball valve is a common ball valve structure, its body is divided into three parts, which are left and right bonnet and the middle valve body. 

Advantages
1. 3-piece ball valves have most complete connection compared to 1-piece and 2-piece ball valves.
2. Three parts of bodies are connected by bolts, which is convenient for installation and dissemble.
3. Widely used in welding ball valves. After welding of left and right bonnet, it can be easily replaced the sealing ring of seat.
4. In the case of frequently switch and fast abrasion, 3-piece ball valves should be prior considered.
5. The runner size of 3-piece ball valve is larger than 1-piece ball valve, which is of stronger circulation.
6. The fluid resistance is small, and its coefficient is equal to the same pipe length.
7. Rapid opening and closing, which is easy to be operated. From full open to full close, it just need rotation by 90°of lever or driving device, which is convenient for remote control.
8. Applicable to a wide range of diameter from millimeters to meters and pressure from high vacuum to high pressure.