Patent GB-1128899-A (GB)
Title: System for producing liquid-filled packages
IPC: B65B9/213
Filed: 1966-07-19
Abstract: 1,128,899. Making liquid filled packages. ATLANTIC RICHFIELD CO. 19 July, 1966 [19 July, 1965], No. 32335/66. Heading B8C. [Also in Division B5] A transverse seal is formed at one end of a tube of flexible material; a predetermined volume of liquid inserted; the tube is clamped closely above the liquid level, partially flattened below the clamped end to force the liquid downwardly in the tube, and transversely sealed beneath the partly flattened portion, whereby an accurate and tight fill is obtained. As described, the tube is formed on a mandrel 13, Fig. 2, by wrapping a web of material, preferably P.V.C., around it and effecting a longitudinal seal by means of an R.F. welder 17. A sealing assembly 20 effects a transverse R.F. weld at the lower end of the tube, and a predetermined volume of liquid is inserted by means of a metering pump 48. A squeezing device 30, see also Figs. 5. . . 5C (not shown), comprising clamps 31 and pressure members 32, is forced by compressed air means to clamp the tube tightly just above the liquid level, the pressure members 32 pressing liquid into the lower end of the tube. The sealing assembly 20 has meanwhile been raised on carriage 25 by a distance equal to the desired length of the package, to a position below the clamped portion, and gripping members 23a, 23b, 24a, 24b, are impelled by pressure cylinder 40 to pinch off the liquid on either side of the welding electrodes 21a, 21b, 22a, 22b which then effect a transverse seal. Finally the carriage 25 descends, pulling down the next length of the web over the mandrel 13 and transverse motion of electrodes 21b, 22b and grippers 23b, 24b impelled by pressure cylinder 56 causes severance of the tube. The whole operation is performed in a timed sequence monitored by a control system (Fig. 3, not shown) including two series-connected pairs of timers controlling the vertical and horizontal welding operations respectively through relays supplying power to the compressed-air systems and by supplying R.F. power directly to the welders. Pressure and limit switches are also provided, and the length of the tube can be controlled by photo-electric means if the web is suiably printed on. Sealing assembly 20.-Opposed pairs of grippers 23a, 23b, 24a, 24b are impelled to grip opposed sides of the web tube by a pressure cylinder 40 connected through a piston 41 to one side of the grippers and through a mechanical linkage 42 to the other side. As shown in Fig. 8, grippers 23a, 23b are made of resilient material and are convex to co-operate with concave surfaces in grippers 24a, 24b, preferably made of Plexiglass (Trade Mark). Shims 126, 127 enable the position of the web material to be controlled during welding. The grippers 24a, 24b are provided with vertical slots (24a<SP>1</SP>), (24b<SP>1</SP>), Fig. 9 (not shown) in order to relieve the pressure of the liquid entrapped between the grippers during welding. The assembly is provided with welding electrodes 21a, 21b, 22a, 22b, R.F. insulated from the machine frame by insulators 111, 114, 141, 143. The electrodes can be cooled by means of water or oil passing through channels 110a, 113a, 115a, 116a. The live electrode side consists of electrodes 22a, 22b while 21a, 21b are ground electrodes. After welding and cooling lower electrodes 22b, 21b move to the left relative to the other pair, together with grippers 24b, 23b all impelled by insulator block 143 which is forced by piston 55 of pressure cylinder 56. This relative movement severs the web tube.