Patent GB-1212790-A (GB)
Title: Method and apparatus for processing products in flexible containers
Inventor: WILSON DONALD CLAYTON
IPC: B65B55/02
Filed: 1968-12-20
Abstract: 1,212,790. Sterilizing apparatus. FMC CORP. 20 Dec., 1968 [26 Dec., 1967], No. 60542/68. Heading A2D. [Also in Division B8] In an apparatus for heat-processing a product such as food in a flexible pouchlike container which has an open edge portion defining a container mouth and has all other edge portions sealed, the processing comprises the steps of applying a closing force across the unsealed mouth of the container to provide a one-way valve, subjecting the container to a heat-treatment medium that includes a liquid to heat the product in the container, submerging at least a major portion of the container in the heating liquid to force gas within the container outwardly through the oneway valve, and sealing the mouth of the container. In one embodiment, flexible containers 22 are held in carriers 94, Fig. 7, by clamps 100a, b, c. The clamps 100b, c are mounted on resilient bars 102, 104 and impart a tension that closes the mouth 36 of each of the containers 22 to form a one-way valve 38. A plurality of carriers 94 are mounted on channel bodies 95 each welded to two supporting arms 96 at opposite ends, Fig. 2. The arms 96 terminate at their upper ends in hooks 98 that hang on pivot pins 90 projecting from two parallel endless chains 60, 62 of a conveyer 55. As shown in Fig. 1, the conveyer 55 transports the carriers 94 through an inlet tunnel 53 into a first chamber of an atmospheric cooking and cooling apparatus 20, where the containers 22 are immersed in water W up to the level of their one-way valves 38, and thence into a second chamber where the mouths 36 of the containers 22 are sealed by a mechanism 57 before passing out through a discharge tunnel 54 to a waterspray cooling system 58 sited above the roof 50 of the cooking chambers. Steam is injected into the water W through a manifold 56 and also into the top part of the cooking chambers adjacent a baffle 61 through valved conduits 56a, 56b. Hydrostatic pressure acting on the sides of the containers 22 forces air and gases formed during cooking out through their one-way valves 38 while they pass through the first chamber. The substantially pure steam atmosphere in the second chamber effects sterilization of the product in the containers 22 after sealing. The sealing mechanism (Fig. 6, not shown) comprises pneumatically actuated electrically heated heat-sealing bars (130, 132). The containers 22 may be made of a heat-sealable laminated film having an outer layer of a polyester resin film, a central layer of thin aluminium and an inner layer of polyethylene. Where a relatively wide container is used, the mouth of the container may be partially sealed at either end to leave a shorter central opening for subsequent sealing after processing. In a second embodiment (Fig. 12, not shown) the conveyer (55a) follows a zig-zag path in a vertical plane so that cooking is effected mainly in a steam atmosphere, the containers being only intermittently immersed in the heated water W for expulsion of gases. In a third embodiment (Fig. 13, not shown) the cooking and cooling apparatus (20b) is pressurized, the container carriers (94b) entering via a hydrostatic leg (201). The products are cooked in pressurized steam and the containers (22b), after sealing, are cooled by transport in their carriers (94b) up through an outlet hydrostatic leg (203) fed with cooling water. In a fourth embodiment (Fig. 14, not shown) the containers (22c) are transported first through an atmospheric cooking and sealing apparatus similar to the Fig. 1 embodiment and then through a pressurized apparatus similar to the Fig. 13 embodiment for sterilizing and cooling. In a fifth embodiment (Fig. 15, not shown) a low pressure cooker having short inlet and outlet water legs (201d, 203d) is used, the first leg (201d) serving to expel substantially all of the headspace air from the containers (22d) before they enter a steam cooking and sealing chamber. On exiting from the apparatus through the outlet water leg (203d) the containers (22d) are sprayed with water as they descend into a trough (226) of cooling water located beneath the cooking chamber.