The Torque Calculation And Optimal Analysis On Structure Of Triple Eccentric Butterfly Valve

In recent years the triple eccentric butterfly value was developed rapidly for its wide range of temperature and pressure, and two-way "zero leakage". Its opening and closing movement is a complex three-dimensional trajectory, required no interference with the butterfly disc and valve seat, and sealing pressure homogeneous distribution. So far there isn't systematical research and standard design, brought about the limitation of the triple eccentric butterfly valve in its development and application to a great extent.The paper analyzed the structure of the triple eccentric butterfly valve at length, defined the triple eccentric butterfly valve, and 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 established function relations between its geometry parameters of primary sections of the butterfly disc and the triple eccentricity.The paper analyzed the force of the triple eccentric butterfly valve disc when it opened and closed, deduced the computation formula of the friction moment and the stem torque under the two situations.The paper deduced the friction moment of the triple eccentric butterfly valve and gave it a qualitative analysis. The results indicated: for the triple eccentric butterfly valve with the same caliber, the axis eccentricity effected on the friction moment minutely; the friction moment would increase with the radial eccentricity increasing; the friction moment would decrease with the angle eccentricity increasing.The paper also deduced the stem torque of the triple eccentric butterfly valve. The results indicated for the triple eccentric butterfly valve with the same caliber, the stem torque would decrease with the butterfly disc thickness increasing; the stem torque would increase with the radial eccentricity increasing; however, the axis eccentricity and angle eccentricity effected on the stem torque minutely.