In 1918 J. C. Pitman and Sons Hotel & Restaurant Equipment Manufacturers, while attempting to work out a more satisfactory method of frying, made some important discoveries. One was that if the small particles of food which ordinarily settled to the bottom of the French Fry pot (where they collected and burned) could be kept away from the intense heat of that part of the kettle, the quality of fried food could be greatly improved. The Pitco Frialator was invented on this basic principle - - and patented. This brought about a complete change in the method of deep fat frying. The fat medium was heated by tubes running through the center of the fat container. This construction permitted all sediment from the food being fried to drip below the heating tubes into a cool zone where it could not carbonize and break down the frying fat.