Patent GB-749304-A (GB)
Title: Improvements in apparatus for the thermal treatment of products in sealed containers
IPC: A23L3/00
Filed: 1951-11-01
Abstract: 749,304. Heat treating food in cans. CARVALLO, P. Nov. 1, 1951 [Nov. 28, 1950], No. 25571/51. Class 49. [Also in Group XXX] In apparatus for the thermal treatment of foods in cans, conveyer chains of the link-pin type transport baskets which carry the containers, and which are open at both ends, the chains forming obturators at both ends of the baskets to prevent accidental ejection of containers from the baskets during transport through the apparatus. In such a sterilizer for canned goods, the cans are disposed in batches in perforated cylindrical baskets which may have unperforated end portions ; the ends of the baskets are engaged by pushers consisting of extensions of alternate pins of a pair of endless conveyer chains on either side of which extensions are arranged extra pins or studs so as to form a forwardly concave member ; the chains run in guides made of bent sheet metal and having extensions for guiding the end portions ; there is play between the ends and guides, so that in an upwardly moving run of the chains the containers rest wholly in the concave pusher members which thereby act as small platforms and prevent friction occurring ; friction occurs in a downwardly moving run where the container ends will contact the guide, since they are resting on only the pin extensions of the chain ; on horizontal runs the baskets are rolled along guides by the pusher members so as to turn the cans in the baskets and stir the contents of the cans. As shown, Figs. 8 and 10, either a vertical or a horizontal undulating system can be arranged, the horizontal arrangement giving the maximum turning of the containers and the vertical arrangement giving the minimum. Two kinds of temperature controlling arrangement are also shown in Figs. 8 and 10. In Fig. 8, the sterilizing temperature is determined by the vapour pressure in a steam chamber 47 which is dependent upon the height of an upper water outlet 81 over the level of hot water at the bottom of chamber 47. This is maintained constant by a float 53 in a communicating chamber 52 the movement of which controls a valve 54 supplying steam to the enclosure 47. Cooling water circulates in counterflow, entering at 80 where the sterilized and cooled products leave the cooler 41, passing down column 44, along passage 51, and up column 49, and leaving at 81 where baskets of fresh articles are entering, thus obtaining maximum thermal efficiency. In Fig. 10, hot water only is used under an overpressure equal to the difference in levels at outlet 81 and in the syphon tube 63 which may be adjusted by admitting compressed air at 83. This overpressure may be much less than the vapour pressure in the sterilizer of Fig. 8. The water in the sterilizing chamber 61 is heated by steam injected at 70 by a pipe arranged within a tube 71 communicating with a reservoir 72 so as to cause water to flow from the reservoir into the bottom of chamber 61. The hot water rising in column 60 is cooled by incoming baskets of fresh articles and overflows at 82 into the reservoir 72, the size of which is equal at least to the total volume of the maximum amount of goods carried by the conveyer in the loaded state. The same water is thus used over and over again. Steam heated pipes 73 may also be provided for heating chambers 61. A separate cooling section 65 is provided with baffles 66 and cooling water enters at 80 where the sterilized and cooled articles emerge, and leaves at 81. In both forms the clearance between the baskets and the walls of the passages is small so as to minimize the production of eddies. A platform is provided on to which the baskets of sterilized and cooled cans are ejected by a reciprocating or rotary pusher, this pusher pushing the baskets stepwise in contacting relationship along the platform. While on the platform, timed pushers carried by a reciprocating carriage eject the cans from one basket and simultaneously fill the next basket with fresh cans from a table which is periodically supplied with a batch of fresh cans by a push bar.