How to distinguish between A-typed center line butterfly valve and triple eccentric butterfly valve
In order to meet various working conditions, the butterfly valve has received wide attention and application along with its continuous evolution and development. The butterfly valve has experienced the evolution from concentric to single eccentric, double eccentric and triple eccentric. This article is mainly to share with you how to distinguish between A-typed center line butterfly valve and triple eccentric butterfly valve, what is the difference between the two:
1.A-typed center line butterfly valve
The structural feature of the A-typed center line butterfly valve is that the shaft center of the valve stem, the center of the butterfly plate, and the center of the body are in the same position. The structure is simple and the manufacturing is convenient. Common rubber-lined butterfly valves belong to this category. The disadvantage is that the butterfly plate and the valve seat are always in a state of squeezing and scratching, with a large resistance distance and rapid wear. In order to overcome squeezing, scratching, and to ensure sealing performance, the valve seat basically uses elastic materials such as rubber or PTFE, but it is also limited by the temperature in the use of the sealing material. This is why people traditionally think of A-typed The reason why the center line butterfly valve is not resistant to high temperature.
2. Triple eccentric butterfly valve
To withstand high temperatures, hard seals must be used, but the amount of leakage is large; for zero leakage, soft seals must be used, but they are not resistant to high temperatures. In order to overcome the contradiction of the double eccentric butterfly valve, the butterfly valve was eccentric for the third time. Its structural feature is that while the double eccentric valve stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the cylinder axis of the body, that is to say, after the third eccentricity, the sealing section of the butterfly plate is not Furthermore, it is a true circle, but an ellipse, and its sealing surface shape is therefore asymmetrical, with one side inclined to the center line of the body and the other side parallel to the center line of the body.