Improvements in valve for vacuum pack closures

摘要

666,963. Closures fitted with valves. DUO-VENT VACUUM CLOSURE CO. Nov. 24, 1947. [Dec. 27, 1938] No. 31093/47. Class 125(iii). [Also in Group XXIX] A valve for receptacles exposed to differential internal and external fluid pressures comprises a valve seat 16 formed by an annular crest merging into an axially extending opening 17, a valve element 26 including a shank 30 having a flange 34 at one end co-operating with the lower end 18 of the opening and a flexible sealing flange 31 at the other end overlying the crest, and means permitting the passage of fluid from the interior of the receptacle to the underside of the sealing flange. As shown, the valve element 26 is formed of resilient material and is pushed into the conical opening until the flange 34.hooks over the end 18. Increased internal or reduced external pressure allows the element to become elongated so that fluid passes through the slot 38 to the space 43 and lifts the flange 31. If the opening 17 is cylindrical, elongation of the member will produce lateral contraction to form a space 43, or the shank may be ribbed. The seal between the flange and the seat can be broken by inserting, e.g. a finger nail, between a reinforcement 33 and the flange and lifting the element. In a modification the wall of the shank is ported. In another arrangement, the element is formed of a rubber washer clamped between a metal cap and a ported metal cylinder which slides in the opening. A perforated seal, e.g. of paper, may be attached to the lid 11 of the receptacle to cover the valve.