Analysis of the advantages and disadvantages of the ball valve

Ball valve: Its opening and closing member is a sphere that is opened and closed by rotating the ball 90° around the axis of the valve stem, which is evolved from the plug valve. The ball valve is mainly used to cut, distribute and change the flow direction of the medium on the pipeline. The ball valve designed as a V-shaped opening also has a good flow regulation function.
Advantages: the lowest flow resistance (actually 0), because it will not get stuck during work (in the absence of lubricant); in a wide range of pressures and temperatures, it can achieve complete sealing; can achieve fast opening and closing, some The structure's opening and closing time is only 0.05~0.1s, which can be used in the automation system of the test bench. When the valve is quickly opened and closed, the operation is free of impact. The spherical closing member can be automatically positioned at the boundary position; when fully open and fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, so that the medium passing through the valve at high speed does not cause erosion of the sealing surface; the structure is compact and light, It can be considered as the most reasonable valve structure for low temperature media systems; the valve body is symmetrical, especially the welded valve body structure, which can withstand the stress from the pipe well; the closing member can withstand the high pressure difference when closing. (11) The ball valve of the fully welded valve body can be buried directly in the ground, so that the valve internals are not eroded, and it is the most ideal valve for oil and natural gas pipelines.
Disadvantages: Because the most important seat seal material of the ball valve is Teflon, it is inert to almost all chemicals, and has a small friction coefficient, stable performance, not easy to age, wide temperature range and sealing performance. Excellent comprehensive characteristics. However, the physical properties of Teflon, including higher coefficient of expansion, sensitivity to cold flow and poor thermal conductivity, require that the design of the seat seal must be built around these characteristics; its regulation performance is worse than that of the shut-off valve. Some, especially pneumatic valves (or electric valves).