Do you know the characteristics of ball valves?

The ball valve evolved from the plug valve. Its opening and closing part is a sphere, which uses the sphere to rotate 90° around the axis of the valve stem to achieve the purpose of opening and closing. The ball valve is mainly used for cutting off, distributing and changing the flow direction of the medium in the pipeline. The ball valve designed as a V-shaped opening also has a good flow adjustment function.

 

Advantages of ball valves

①Have the lowest flow resistance (actually 0);

②Because it will not get stuck during work (when there is no lubricant), it can be reliably used in corrosive media and low boiling point liquids;

③Complete sealing can be achieved in a larger pressure and temperature range;

④ Fast opening and closing can be realized, and the opening and closing time of some structures is only 0.05~0.1s to ensure that it can be used in the automation system of the test bench. When opening and closing the ball check valve quickly, there is no shock in operation.

⑤The spherical closure can be automatically positioned at the boundary position;

⑥The working medium is reliably sealed on both sides;

⑦When fully open and fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, so the medium passing through the valve at high speed will not cause erosion of the sealing surface;

⑧Compact structure and light weight, it can be considered as the most reasonable valve structure for cryogenic medium system;

⑨The trunnion mounted ball valve body is symmetrical, especially the welded valve body structure, which can withstand the stress from the pipeline well;

⑩The closing piece can withstand the high pressure difference when closing.

 

Disadvantages of ball valves

①Because the main seat sealing ring material of the ball valve is polytetrafluoroethylene, it is inert to almost all chemical substances, and has a small friction coefficient, stable performance, not easy to age, wide temperature application range and excellent sealing performance The comprehensive characteristics. However, the physical properties of PTFE, including high expansion coefficient, sensitivity to cold flow, and poor thermal conductivity, require the design of valve seat seals to focus on these characteristics.

 

Therefore, when the sealing material becomes hard, the reliability of the seal is impaired. Moreover, PTFE has a low temperature resistance grade and can only be used at less than 180°C. Above this temperature, the sealing material will deteriorate. When considering long-term use, it will generally only be used at 120°C.

 

②The adjustment performance of the ball float valve is worse than that of the stop valve, especially the pneumatic valve (or electric valve).

 

 

What is the difference between pvc ball valve and 3 way ball valve? Follow our next article to tell you the answer.