Limitations of Butterfly Valves

Although the butterfly valve has a wide range of functions, there are always some limitations when it is used. So what are its specific limitations? In which occasions are butterfly valves not suitable?

First of all, let’s talk about the advantages of butterfly valves. Butterfly valves have a simple structure, small size, light weight, and are composed of only a few parts. Moreover, it can be quickly opened and closed by rotating 90°, which is simple to operate. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body. Therefore, the pressure drop generated by the valve is very small, so it has good flow control characteristics. Butterfly valves have two sealing types: elastic seal and metal seal. For elastic seal valves, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.

Valves with metal seals generally have a longer life than valves with elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to higher operating temperatures, while elastic seals have the defect of being limited by temperature.

If the butterfly valve is required to be used as a flow control, the main thing is to correctly select the size and type of the valve. The structural principle of the butterfly valve is particularly suitable for making large-diameter valves. Butterfly valves are not only widely used in general industries such as petroleum, gas, chemical industry, and water treatment, but also in cooling water systems of thermal power plants. Commonly used butterfly valves are wafer-type butterfly valves and flange-type butterfly valves. Wafer-type butterfly valves use stud bolts to connect the valve between two pipe flanges, while flange-type butterfly valves have flanges on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flanges. Wafer-type butterfly valves are more commonly used in water treatment systems. Because the mounting bolts of wafer-type butterfly valves must be long, that is, the bolt length = wafer-type butterfly valve body thickness 2 flange thickness gasket thickness, it is not suitable for use in high pressure situations.