100,000,000,000 CANS

Te Awamutu Courier, Volume 53, Issue 3823, 19 October 1936, Page 3

100,000,000,000 CANS

PRODIGIOUS ANNUAL CANNING OUTPUT. (By R. Jamieson, in Weekly Scotsman.) Little more than a hundred years ago scores of skilled workmen were employed in making entirely by hand the cans in which Peter Durand, an English merchant was to send preseijved foodstuffs to all parts of the world. To-day automatic machinery is turning out hundreds of thousands of cans a minute and the world production of canned foodstuffs runs to the amazing total of nearly one hundred thousand million cans! Neither Britain nor America can claim to have invented the canning method for preserved foodstuffs—the English patent of Robert Durand granted in 1810 was for “an invention communicated to him by a certain foreigner residing abroad, of the method of Preserving Anima] Food, Vegetable Food, and other perishable Articles a long time from perishing or becoming useless.” Probably the foreigner referred to was Nicholas Appert, who had just been awarded a prize by the French Government for a more certain method of preserving food for the French armies. What he had discovered was that food could be preserved by a process of heating alone, and though the results were undeniable, it was not until Pasteur discovered later that micro-organisms were responsible for food decay that the explanation of this “sterilisation” by heat was seen. From the first Durand favoured the “tinplate canister,” though his patent provided for the use of “bottles of glass, pottery, tin, or other metals or fit materials.” And the name “tinplate canister” must be traced through an intermediate stage of “tin can” to “tin” in Britain and “can” in America. THE FIRST CANS. The first cans we're expensive to produce and wasteful of metal and time. They were fully prepared with a small hole left in the lid through which the contents were poured, the hole being sealed up with a soldered seal. The first of a long series of improvements is the invention of one, Angilbert, who patented an amazing contraption in 1833. It required a ring of hot coals to seal it and a similar ring to open it! But it did have an important improvement in a small vent hole, which remained open until the sterilising process was complete and could then be very effectively sealed. Incidentally, it was the first recorded instance of the open top can, the type which is almost universally used to-day. There is no need to go through a catalogue of all the queer cans recorded in the archives of the world’s patent offices in the last century—they would indeed make a museum of oddities if brought together, and the housewife would be puzzled to know how to open half of them. Clumsy and unhygienic as most of them were, they were nevertheless stages in the development towards these convenient and cheap little cans of to-day. At first the cost of production was very high, and many examples are efforts to make cans so that they could be used again and again. The problem of easy openingaccounts for more monstrosities, as they seem to us. AN AMERICAN INVENTION. But by far the most important event in the history of canning was the invention of the drop press is America in 1847. It made possible the large-scale production of conveniently shaped and cheap tinplate containers. And, of course, it was America that largely developed the canning business in the nineteenth century. But its virtual monopoly has been lost since the Great War, and Britain, the Continent, and even the Far Eastern countries are fast increasing their production. Apart fi,om the industry of canning, the production of cans is an intricate process, combined even as it often is in one great machine. Blanks for the bodies of open-top cans are prepared by passing sheets of tinplate through a shearing machine, which first slits and trims the sheets into strips, which are then crosscut to make blanks the exact length and breadth of the body of the can. Fed into another machine these blanks are notched, the edges which will form the seam hooked, bent round a mandril and the hooked edges linked up and soldered. A detail or two, such as wiping off the excess solder and blowing cold air on the seam to harden it, complete the process through which a hundred cans pass in twenty seconds! Even more intricate machinery attaches bottoms with a double seam at the same rate and tops after filling at about half the speed. This open-top type of can, so-called because the whole top is open when filled and the top put on in much the same way as the bottom with a double seam, is favoured for many reasons, chief among them being the ease with which it can be thoroughly cleaned and sterilised, and also the fact that meat or other solid matter up to a size equal to the diameter of the tin can be filled without trouble. NEW PROBLEMS. But however high a pitch has been reached the investigation of new

problems continues to occupy the attention of scientists in all parts of the world—especially in America and Britain. One of the. most difficult problems to be tackled is that of corr,osion on the inside of the tins. It may safely be assumed that with the foodstuffs now offered to the public corrosion will not occur, but there arei many which might be offered ; f they did not corrode the cans. It is along- these lines that the Low Temperature Research Station at Cambridge has been working for some years. They have found out to some extent at least why, as a general rule, tinplate is relatively free from corrosion, and why some things do corrode it. It will not be long before they find out how to avoid this corrosion and we shall have new varieties offered in cans. A recent development has been the production of tinned cheese. Cheese in maturing gives off carbon dioxide, and the problem has been to design an efficient valve through which this carbon dioxide can escape, which will be cheap enough to throw away with the can afterwards. This has been done in a most ingenious way, and it is claimed that the cheese sold in cans has a higher degree of purity than that marketed in the normal Way. SOME FIGURES. And now for some figures! The hundred thousand million I mentioned is not fantastic—it is a fairly conservative estimate of the number of cans filled this year. In America the total pack of fruits vegetables, and soups amounted in 1933 to 3200 million cans! In addition there is fish, meat, and dairy products, for most of which the figures refer to weights rather than cans. Fish products account for 13 million cases, each containing between 50 and 100 cans—another one thousand million cans. Unsweetened canned milk, 1714 lbs! Meat products probably about 150 million lbs! Figures for Britain are of little value, as a rapidly expanding industry has to be dealt with. It is a fact that between 1925 and 1930 the canning of fruit and vegetables in creased from about 3-4 million to about 100-120 million cans. The rise is phenomenal. The most important fruit pack is plums, and dried peas represent most of the increase in vegetables. Meat is also packed and there are several canneries on the cast coast where fish, mainly herring, is packed, Dairy produce, however, is now an important packing commodity. In the year 1933-34 nearly 10 million gallons of milk were condensed and canned and the canning of cream is a distinctly promising development in the canning trade.