| 摘要 |
<p>A flapper valve has integral, oppositely projecting hinge pins mounted in a recess provided between two abutting tubular housing members. The flapper valve is of cylindrical segment configuration so as to maximize the opening within a conduit in which it is mounted when the flapper valve is pivoted to its open position. The spring bias urging the flapper valve to the closed position is provided by helical springs mounted in surrounding relationship to the axis of the conduit and in an annular recess provided between two abutting tubular housing members. The bottom surface of the actuating sleeve for the flapper is contoured so as to exert a minimum unbalanced torque on the flapper valve during opening with the mechanical opening force being balanced by an opposing force exerted by fluid pressure. Such construction permits a substantial reduction in the size of the hinge pins and the space required to mount the pins and the helical springs, thus reducing the radial proportions of the flapper valve assemblage to increase the open bore diameter.</p> |
