GB1155081A - Improvements in Packaging - Google Patents

Abstract

1,155,081. Packaging in special atmospheres. P. EISLER. 16 June, 1966 [17 June, 1965], No. 51327/64. Heading B8C. [Also in Division A2] Goods to be heat processed, such as foodstuffs to be sterilized and cooked, pharmaceutical products, chemicals which need to react at the time of packaging, and surgical and scientific instruments, are filled into unsealed containers which are then enclosed in an atmosphere of a medium harmless to the goods at the processing temperature, heating the goods to the temperature and for the time required by the heat processing, increasing the pressure of the medium at a rate during the rise in temperature to prevent pressure dependent damage to the goods, thereafter cooling the goods while reducing the pressure of the medium at a rate to prevent pressure dependent damage to the goods, hermetically sealing the container, and removing it from the medium-containing enclosure. In one embodiment a container 11, incorporating electrical heating elements in its wall with electrical terminal tabs 12, 13, is filled with foodstuffs and passed into a pressure chamber 16. The container 11 is then electrically heated by connection to a power supply via bus-bars 17 while the chamber 16 is progressively pressurized with sterile-filtered air by a pump 23 and a filter 24. After processing, the containers 11 are cooled, aided by cooling water flow through a hollow shelf 26, and the air pressure in the chamber is progressively reduced by venting through a valve 27. Automatic control of the air pressure and the temperature of the containers 11 are provided by pressure and temperature sensors 19, 21 respectively acting through a control box 18 to control the power supply to the bus-bars 17 and the operation of the valve 27. The containers 11 are then sealed. Other heating means specified are high-frequency radiation, hot plates, radiant heat and eddy currents. In another embodiment (Figs. 2-5, not shown), containers (11a) are conveyed through a series of chambers separated by air-tight gates with a long central chamber (II) for heat treatment of the containers (11a at constant elevated pressure and three shorter chambers (1) for the initial raising of temperature and pressure, (III) for cooling after treatment, and (IV) for sterile sealing of the containers (11a). Steam may replace air as the pressure medium where the goods to be processed are not adversely affected thereby.