Gas fired gun and plastic valve therefor

摘要

The plastic valve includes an elongated plastic valve stem and an elongated pin. An end portion of the pin projects from an end of the plastic stem with the remaining portion of the pin being wholly encapsulated by the stem. The pin is generally cylindrical and has a pair of reduced diameter portions defining shoulders forming impact surfaces which butt the axially opposed portions of the encapsulating stem. The stem preferably has a tapered sealing surface irradiated by beta rays to provide a sealing surface highly resistant to creep and deformation. The sealing surface is coated with Fluorocarbon Polymer to reduce its chemical activity and to improve its sealing characteristics. The opposite end of the pin serves as a deflector opposite the molding gate to control the flow of plastic material during injection molding of the stem to prevent weld lines on the seal surface.