GB1456881A - Packaging apparatus method and product - Google Patents

Abstract

1456881 Packaging liquids PERMTEK Inc 12 Jan 1974 01562/74 Heading B8C [Also in Division G1] A method of hermetically sealing a body of liquid in a gas free interior of a thermoplastic package comprises the steps of providing a vertically oriented tubular package blank 11 sealed at the lower end, filling a portion of the tube 11 including the sealed end with liquid under pressure maintaining a predetermined level of liquid in the blank above the blank portion to maintain package size, exteriorily engaging opposed wall portions of the filled tube portion and pressing the same together to engage opposing inner surfaces thereof over a selected area traversing the tube, eliminating all liquid from between the engaged surfaces, and heat-sealing the engaged wall portions along a zone within the area. As shown, two webs 14, 14<SP>1</SP> e.g. of polyethylene, extend downwardly, on opposite sides of a liquid filler tube 13 through a cutting-and-sealing assembly 15 which, by means of a pair of electrically-heated knives 38, 40 and 38<SP>1</SP>, 40<SP>1</SP>, Fig. 2, heat seals together the opposite lateral margins of the webs and trims off the excess edge material 50, which is drawn off by rollers 16. The formed tube extends downwardly through a photoelectric, fluid-level, control assembly 18, Fig. 3, to a feeding assembly 19, Fig. 4, which periodically grips the opposite margins of the tube and pulls the latter downwardly, through the assemblies 15, 18 to a heat-sealing and cut-off means 20, which serves to produce heat-sealed margins to form hermetically sealed, gas-free, packages of a length which is selected by the feeding assembly 19, and to a vertically-adjustable stop gauge 21. The cut -off means severs the tube to provide individual packages. The heatsealing and cut-off means 20 comprises a sealing plate member 112, Fig. 1, with a sealing knife portion 113 and which is mounted on the upper arm 110 of a T-shaped rocker arm 106 which is pivotally mounted at 108, is pivoted at 103 to a solenoid actuating mechanism 100, and is urged by a spring 109 so that, in its inoperative position, the arm abuts a stop member 102. Lower and upper wiper blades 118, 119, are mounted respectively on upper and lower brackets 120, 121, carried by the sealing plate 112, by means of pairs of leaf springs 125, 125<SP>1</SP> which cross each other on opposite sides of the sealing knife portion 113 so that the blades intersect substantially at right angles immediately in front of the tip-end 116 of the knife portion 113. A stationary welding knife assemly comprises a stationary heater blade 132 and a guard 134 secured to a support 131. At the beginning of a sealing operation the solenoid 100 is energized and the sealing member 113 is advanced. The wiper blades 118, 119 first engage the wall 14<SP>1</SP> of the tube, Fig. 5, and then pinch the walls 14, 14<SP>1</SP> firmly against the stationary heater blade 132, before spreading laterally, Fig. 6, to wipe effectively the liquid from the zone of thermal sealing. Continued advance of the heater blade 113 causes the latter to form a seal across the tube and sever it as the two blades 113, 132 meet. The solenoid 100 is then de-energized to return the blade 113 to its inoperative position, the feeder assembly 19 releasing the tube 11 and then being actuated to rise and re-grip the tube and downfeed it into the gauge 21. The liquid level assembly, which includes a source of light 55, Fig. 3, and a vertically adjustable photocell 56, senses the absence of liquid in the tube, and, by means of appropriate circuitry, signals for the inflow of make-up liquid via the filler tube. The interior surfaces of the plastics layers 14, 14<SP>1</SP>, Fig. 9, are scored with a series of fine-line scratches to provide the bag 14 with a uniform capillary distribution system.