| 摘要 |
A mold and method of forming a butterfly valve and the novel valve formed. In the method, a valve skeleton (200) having a body portion (202), a hollow neck (210) extending from the body portion to receive a valve stem and a cruciform-shaped actuator plate portion (212) on the hollow neck is suspended in a mold cavity (30) in inverted orientation, and reaction injection molding polymer is injected by laminar flow into the bottom of the mold cavity with an amount of polymer sufficient to fill the space from the bottom up, encapsulating the skeleton, and overfill the space to force the leading edge of the polymer out the top of said space into an escape chamber (188) to entrap residual gases into a severable offal member. The polymer encapsulates the cruciform-shaped actuator plate while filling the corner spaces (214) thereof, except for fastener orifices (311). A gate (138) at the bottom of the mold assures laminar flow of polymer into the mold cavity. The valve skeleton may have a plurality of radially extending mounting lug portions fitting into lug-receiving cavities (130') of the mold including at least one mounting lug-receiving cavity projecting radially outwardly and upwardly, the said mold cavity including an upwardly oriented flow passage (131) up from said at least one lug-receiving cavity to the polymer-receiving escape chamber (188), for flow of air from the at least one lug-receiving cavity through the flow passage to the escape chamber. <IMAGE> |
