CHECK VALVE FOR FLUID BLADDERS

摘要

A check valve provides a one-way fluid passage from without to within a flu id bladder formed by a pair of plastic sheets sealed together about their periphery. The check valve is formed by a pair of superimposed films of thermoplastic material, generally equal in length, thermally bonded together at predetermined areas to define the fluid passage throughout the length of the valve. The inlet end of the valve has a V-shape edge with the apex pointing in a direction opposite the one-way fluid flow. Each of the films, adjacent the V-shape edge of inlet~end, is sealed to one of the outer sheets where the valve enters the bladder by a seal line of similar V-shape. Each of the films has a high-gloss, cohesive inner surface and a matted, non-cohesiv e outer surface. At least one of the films includes, on its inner surface, a release material disposed at a location which corresponds to the area at the inlet end of the fluid passage through the peripheral seal of the bladder to prevent the fusing together of the films at that area of the seal. The terminal ends of the superimposed films extend in surface-to-surface relation into the bladder to provide a "duck-bill" typ e check valve.