| 摘要 |
PURPOSE: A check valve for injecting gas into a gas tube for automatically sealing perfectly also enabling recycling repeatedly as having a simple structure is provided. CONSTITUTION: A check valve is made of one material selected among soft PVC, latex rubber, silicon rubber, epoxy resin and polyurethane resin. It contains a vent hole(7) for injecting gas at the central position of an opening piece(5) of an upper film(10) as attaching the opening pieces(5,5') with an adhesive(6). The check valve is operated by the steps of: inserting a straw for injecting gas into a front rim opened, inputting gas, expanding the film(10), injecting gas through the vent hole(7) into a gas tube, if the straw is removed, attaching the vent hole(7) part on the opening piece(5,5') by an earthing force and by a self elastic force of the polyethylene film not to flow back air.
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