The three eccentric butterfly valve is a new butterfly valve product. Prior to the advent of three eccentric butterfly valve, the most widely used industrial pipe was a soft-seal butterfly valve and a metal-seal butterfly valve with a single eccentric double eccentricity. Both types of butterfly valves have their own advantages, but they also have obvious shortcomings. Soft seal butterfly valve has the advantage of good sealing performance, can achieve zero leakage; the disadvantage is not suitable for high temperature and high pressure environment, not wear and tear. The advantage of the hard-sealed butterfly valve is that it can adapt to the conditions of high temperature and high pressure, but the sealing performance is poor. In order to solve the shortcomings of the two types of butterfly valves and better serve our production work, triple eccentric butterfly valves came into being and have been widely used.
The advantages of triple eccentric butterfly valve
Three eccentric butterfly valve also belongs to the metal hard seal butterfly valve, which is characterized by high temperature, corrosion resistant alloy material surfacing in the valve seat sealing surface layer, the multi-layer soft stack seal ring fixed on the butterfly board, such The process makes the three-offset butterfly valve more resistant to high temperature and high pressure than traditional butterfly valve products and is more resistant to corrosion. At the same time, because of the unique design of the three eccentricity, the valve is very easy to operate. When the valve is closed, the moment of the transmission mechanism increases to provide a compensation seal, greatly improving the three eccentricity. Butterfly valve sealing performance, while extending the life of the butterfly valve. What is the three eccentricity of three eccentricities?
The first eccentric: The valve shaft is located behind the valve plate shaft so that the seal can completely and tightly contact the entire valve seat.
The second eccentricity: The centerline of the valve shaft deviates from the centerline of the pipe and the valve, which is protected from the opening and closing of the valve.
3rd eccentricity: The seat cone shaft deviates from the centerline of the valve shaft.
This eliminates friction during closing and opening, and achieves a uniform compression seal around the entire seat.
Disadvantages of three eccentric butterfly valve
The perfect thing is more or less flawed and imperfect. The three-offset butterfly is no exception. Its disadvantages are the following two points:
1, the special process of the three eccentric butterfly valve, the structure of the butterfly plate will be relatively thick, so if the three eccentric structure of the butterfly valve on the small diameter pipeline, in the open state, the resistance of the butterfly plate for the flow medium in the pipeline will be very large, flow Large resistance, so in general the three eccentric butterfly valve is not suitable for DN200 below the small diameter pipeline.
2. In the normally open pipeline, the valve seat sealing surface of the three-offset butterfly valve and the level seal ring on the butterfly plate are subject to frontal flushing. A long time will affect the sealing performance of the valve.