Butterfly Valve Structure Analysis And Kinetic Study

With the development of the industrial technology,the general soft seal butterfly valve has not been satisfied with the demand in the industry, so the metal seal butterfly vavle has been developed.The tri-eccentric butterfly vavle is the most advanced during the butterfly valve development and evolvement.But,at present, the tri-eccentric butterfly valve has not been studied thoroughly at home,and has not been formed a perfect theory system, brought about the limitation of the tri-eccentric butterfly vavle in its development and application to a great extent.The paper analyzed the struture of the tri-eccentric butterfly vavle at length, defined the tri-eccentric butterfly valve ,educed the geometry function and its characteristic about the section of the butterfly disc.The results indicate: the parallel contour line across butterfly disc thickness is normal ellipse, thereby eslablished function relations between its geometry parameters(long axis and short axis) of three primary sections of the butterfly disc and the tri-eccentricity;In order to avoid interference between the butterfly disc and the valve seat as well as the valve body, combining the torque, we obtained the feasible range about the rotation center of the tri-eccentric butterfly vavle. In succession, we should test whether the rotation center of the tri-eccentric butterfly vavle was right, brought forward a method to test the seal fit interference,designed the program about the seal fit interference and gave the corresponding results which the program was run.If applied experiential formula mechanically to calculate the dynamic moment of the tri-eccentric butterfly vavle , its errors for the results would be larger. The paper, by virtue of the postulate of flow with fixed constant, eddiless of ideal liquid ,calculated laplace equation by finite difference method in rectangular coordinates ,gained pressure distribution on the butterfly disc section , thereby figured out its dynamic moment under each opening angle and the method was feasible for calculating dynamic moment of symmetry or not ,designed the program and described the curve of dynamic moment.Finally, the paper infered their laws.The paper deduced the seal torque of the tri-eccentric butterfly valve and gave it a qualitative analysis. The results indicated :for the tri-eccentric butterfly valve with the same caliber,theseal torque would decrease with the butterfly disc thickness increasing;the seal torque would increase with the radial eccentricity increasing;however,the axis eccentricity effected on the seal torque minutely;the seal torque would increase with the half cone angle increasing appreciably of the cone which the butterfly disc belonged to. so,we gave the seal torque curves respectively.Based on the theory analysis above-mentioned, according to the given parameters, we designed the three dementions figure of the tri-eccentric butterfly valve.