Plastic valve bag

Claim 1

A BAG COMPRISING: A SHEET OF FLEXIBLE PLIABLE THERMOPLASTIC MATERIAL FOLDED TO FORM A FLATTENED TUBE WITH EDGE PORTIONS OF THE SHEET OVERLAPPED ON THE FRONT SURFACE ALONG NEAR BUT SPACED FROM ONE EDGE OF THE TUBE, SAID PORTIONS BEING HEAT-SEALED TOGETHER TO FORM A LONGITUDINAL SEAM, THE SEALING BEING INTERRUPTED FOR A DISTANCE NEAR THE TOP OF THE BAG TO PROVIDE A VALVE OPENINT BETWEEN THE OVERLAPPED PORTIONS; A SLEEVE IN SAID VALVE OPENING, SAID SLEEVE BEING FORMED OF AN AREA OF FLEXIBLE PLIABLE THERMOPLASTIC FILM MATERIAL FOLDED UPON ITSELF ALONG THE LOWER EDGE OF THE VALVE AND PROVIDING FRONT AND REAR SLEEVE SURFACES PROTRUDING FROM THE OPENING OF THE VALVE INTO THE BAG, THE REAR SURFACE OF SAID SLEEVE AT ITS OUTER END BEING HEAT-SEALED ALONG ON THE UNDERLYING OVERLAPPED PORTION, THE FRONT SURFACE OF THE SLEEVE BEING HEAT-SEALED ALONG THE UNDER SURFACE OF THE OVERLYING LAPPED PORTION; AND CLOSURE MEANS FOR THE TOP END OF THE BAG FORMED OF A FLEXIBLE THERMOPLASTIC STRIP OF GENERALLY U-SHAPED CROSSSECTION LOCATED ALONG ASTRIDE OF AND WITH ITS EDGES MERGING WITH AN INTEGRALLY JOINED TO THE TOP END EDGE PORTIONS OF THE FLATTENED BAG TUBE AND THE TOP END EDGES OF SAID FRONT AND REAR SURFACES OF THE SLEEVE.