Flange butterfly valve is a kind of butterfly valve, which refers to a butterfly valve whose connection form is flange connection. It is a valve with a wide variety of uses, as well as another butterfly-connected butterfly valve. It is also a type of butterfly valve with a large market demand.
Compared to other types of valves, such as flanged gate valves, flanged globe valves, flanged ball valves, etc., flanged butterfly valves have a very simple structure. Only flanged valve bodies, stems, discs, seats and drive units are available. It is composed of a few parts. In addition, compared to other valves, the flanged butterfly valve is smaller and lighter in weight and is more suitable for making large-diameter valves. With the improvement of manufacturing technology, flanged butterfly valves can be used in more and more working environments. It can be used to regulate the flow, and it can also be used to cut off the flow. It gradually replaces the application of flanged gate valves, globe valves, and ball valves in pipeline systems.
Flange butterfly valve can be divided into four kinds: handle flange butterfly valve, turbine flange butterfly valve, pneumatic flange butterfly valve and electric flange butterfly valve according to different drive devices. Both the handle and the turbine need to be manually operated in the field; flanged butterfly valves installed with pneumatic or electric devices are automatic valves. They are generally used in high-altitude or complex working conditions that are not suitable for manual on-site operation,which is also adapted to the current development of China's industrial automation process.
Flange butterfly valve can be divided into soft seal flange butterfly valve and hard seal flange butterfly valve according to different sealing surfaces. The soft seal flanged butterfly valve is usually also a midline type structure. The material of the seal ring is rubber or fluorine plastic. The sealing performance of this flanged butterfly valve is very good, and almost zero leakage can be achieved, but now the material of rubber and fluorine plastic itself, Soft-sealed flanged butterfly valve is not suitable for high temperature and high pressure medium. Generally, the working temperature of rubber material is around -50°C~-80°C, working pressure is less than 2.5Mpa, and working temperature of fluorine plastic material is -196°C~200°C.
Hard-seal flanged butterfly valves are usually eccentric butterfly valves, mostly double-eccentric and triple-eccentric. The hard-seal butterfly valve seals are made of hard metal.
This type of flanged butterfly valve is usually not suitable for making small calibers. When the butterfly valve is fully opened, only the thickness of the butterfly plate is the resistance through which the medium flows. The butterfly plate of the eccentric flange butterfly valve is very thick. If it is used in a small aperture, the fluid resistance is very large. The hard-sealed flanged butterfly valve can be used in a high temperature and high pressure environment, has a very good high temperature and erosion resistance, and has a longer service life than a soft seal. But the disadvantage is poor sealing performance.