In the 1930s, the Americans invented the butterfly valve, and then it was introduced to Japan in the 1950s, and it was widely adopted in Japan in the 1960s, and it was promoted in China in the 1970s. Although China began to invest in research and production in the field of butterfly valves is not very early, but the speed of development is very high, and the results of development are also very rich. At the beginning, the butterfly valve mechanism is basically based on the middle line butterfly valve, with the improvement of the process and the butterfly valve has been widely used in various fields of the industry, which also makes the demand for the butterfly valve in the industry increased: high temperature resistance, high performance and so on. Demand driven creation, through the efforts of Chinese manufacturers, the performance of the butterfly valve has been further improved, creating a wider range of temperature and pressure, reliable sealing performance, and longer service life of the butterfly valve. Double eccentric butterfly valve is improved on the basis of single eccentric.
As China’s current first-class double eccentric butterfly valve manufacturer, today TWT wants to talk about double eccentric butterfly valve in detail.
Double eccentric butterfly valves’ improvement process
In order to solve the problem of squeezing the butterfly plate and the seat of the concentric butterfly valve, a single eccentric butterfly valve is first produced, and its structural characteristics are: the stem axis deviates from the center of the butterfly plate. Although this improvement reduces the friction to a certain extent, but the effect is not much better, double eccentric butterfly valve is further improved on the basis of the single eccentric butterfly valve, is currently more widely used butterfly valve, its structural characteristics are: the stem axis deviates from the center of the butterfly plate, but also deviates from the center of the body.
This improvement of the double eccentric butterfly valve greatly eliminates the unnecessary excessive extrusion and scraping phenomenon of the butterfly plate and the seat, reduces the opening resistance, reduces the wear, and improves the life of the seat, so the double eccentric butterfly valve is called a high-performance butterfly valve.
Double eccentric butterfly valve’s working mode
Double offset high performance butterfly valve is mainly composed of valve body, valve plate, valve core, valve seat, valve cover, support rod, shaft head, cover, detector, gasket body and other components.In normal operation, the pressure between the two outlets of the valve body is very small, when the fluid flows, the valve will automatically open to let the fluid flow through; When the fluid is stopped, the valve automatically closes, blocking the fluid flow.
Material of double eccentric butterfly valve
Double eccentric butterfly valves can also use metal seats, which improves the application of butterfly valves in high temperature fields. However, because its sealing principle is a position sealing structure, that is, the sealing surface of the butterfly plate and the seat is in line contact, and the elastic deformation caused by the butterfly plate squeezing the seat produces a sealing effect, so the closing position is very demanding (especially the metal seat). Therefore, ductile iron seats are common in double eccentric butterfly valves.
Ductile iron double eccentric butterfly valve’s structure is simple and compact, light weight, good sealing performance, easy to operate, widely recognized by the industry.
Application of double eccentric butterfly valve
Double eccentric butterfly valve has the characteristics of good sealing, small flow resistance, corrosion resistance, etc., so it is widely used in the following fields:
- Chemical industry
- Metallurgical industry
- Power industry
- Oil and natural gas industry
- Food and pharmaceutical industries
If you happen to need a double eccentric butterfly valve, please contact TWT,China, we will provide the best quality and the most sincere service.