Packaging apparatus

Claim 1

Apparatus for hermetically sealing, between opposing walls of a thermoplastic package, a gas-free body of liquid which is vaporizable at atmospheric conditions, said apparatus comprising means for forming a vertically elongated tubular package blank sealed along the bottom and lateral margins thereof, means for filling said blank with the liquid being packaged, means for controlling said filling means to maintain a predetermined head of liquid in said blank to control package size, means for heatsealing said blank within an area spaced from the bottom margin of said blank and located in a part of said blank filled with liquid, means for severing said blank within said area, and means for avoiding vaporization of the liquid during heat-sealing by displacing the liquid in said blank from said area prior to heatsealing and for maintaining the liquid in spaced relation from said area during heat-sealing, said means for avoiding liquid vaporization comprising means for engaging the opposed surfaces of the walls over a selected region which include said area and which extends above and below said area, and means for actuating said wall engaging means to press together opposing interior surfaces of said walls in said selected region with sufficient pressure so as to eliminate liquid therebetween, and to maintain together the interior surfaces of said walls in said selected region during heat-sealing so as to retain the liquid being packaged in spaced relation to said area.