Ball valves are mainly used to connect or cut off medium in pipelines, especially the position which need to be opened or closed rapidly. Ball valves have been widely utilized for the advantages of simple structure, light weight and good sealing. Ball valves consist of body, bonnet, base, ball and stem. Ball with hole is the core of ball valves. The ball rotates with stem to open or close valve. Ball valves are classified into floating ball valves and trunnion ball valves. The ball of floating ball valves can float freely. Based on different base, floating ball valves can be classified into trunnion base and flexible base. Floating ball valves with trunnion base have two trunnion bases made of fluorine plastic. Floating ball made of carbon steel or stainless steel exits between two bases. A hole is on the ball. When stem rotates, the hole is vertical to channel of valve. Pressure of medium pushes ball to base to realize seal.

 

Selection principles of ball valves:

1. Pipelines of petroleum or gas which need to be cleaned or planted under ground can use full bore fully welded ball valve. Pipes on ground use fully welded ball valve or flanged ball valve. Branch pipes use flanged ball valve or fully welded ball valve.

2. Pipelines and storage devices of refined oil use flanged ball valve.

3. Urban pipelines of gas use flanged or internal thread floating ball valve.

4. For oxygen pipelines in metallurgy, flanged trunnion ball valve having been degreased strictly is suitable.

5. For pipelines under low temperature, low temperature ball valve with bonnet is suitable. 

6. Pipelines of catalytic cracking devices in oil refinery utilize lift ball valve.

7. Pipes which transport corrosive medium in chemical industry utilize stainless steel ball valve having austenitic stainless steel ball and PTFE seal ring.

8. Pipes under high temperature in metallurgy, electricity, petroleum or heating system utilize metal hard seal ball valve.

9. When controlling flow, worm geared, electric or pneumatic regulating ball valve with V mount is suitable.