# US 4,397,875 A · Method of heating food > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,397,875 A - Document ID: US4397875A - Status: Granted - Kind: A - Application number: 06/254,165 - Filed: 1981-04-14 - Granted: 1983-08-09 - Earliest claimed: 1980-09-08 - Assignees: UMC Industries, Inc. - Inventors: John W. Gilliom - Web page: https://patentgrep.com/patent/US4397875A ## CPC - A47J 27/14: Cooking-vessels for use in hotels, restaurants, or canteens - A23B 2/82: Thawing subsequent to freezing - A23L 5/17: {in a gaseous atmosphere with forced air or gas circulation, in vacuum or under pressure} - A47J 37/0623: {Small-size cooking ovens, i.e. defining an at least partially closed cooking cavity (A47J37/0605 takes precedence)} - A47J 37/0641: {with forced air circulation, e.g. air fryers} - G07F 17/0078: {Food articles which need to be processed for dispensing in a hot or cooked condition, e.g. popcorn, nuts} - G07F 17/0085: {Food articles which for processing need cooking in a liquid, e.g. oil, water} - A47J: KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES - A23B: PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES - A23L: FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF (preservation thereof A23B) - G07F: COIN-FREED OR LIKE APPARATUS (coin sorting G07D3/00; coin testing G07D5/00; {handling coins or paper currencies apart from payment activated apparatus G07D; payment architectures, schemes or protocols G06Q20/00}) ## Abstract Apparatus for heating food, such as a serving of partially or fully precooked french fried potatoes supplied in a refrigerated or frozen state and requiring heating for being eaten, comprising a blower for blowing air, a heater for heating the air, a support for holding a receptacle containing the food in position for heating of the food by the heated air, and a system for causing the air to sweep through the receptacle and blow over and around the food in the receptacle for rapidly heating the food solely by the air. And a method of heating the food involving holding a receptacle containing food in a stream of high-velocity heated air and constraining the air to sweep through the receptacle and over and around the food in heat exchange contact with the exposed surfaces of the food. ## Claims ### Claim 1 The method of heating food in a convection oven, comprising: placing the food in a pan; inserting the pan containing said food through an access opening in a convection oven into a compartment in the oven at the lower end of a ductwork system in the oven, said ductwork system comprising an air delivery passage, adapted for delivery of air from a lower end thereof down into the pan in said compartment and an air return passage extending up from the lower end of said ductwork system, interengaging the pan, all around the pan, with the lower end of said ductwork system to cause the pan to cooperate with the air delivery and air return passages in the ductwork system and to form a generally closed passage, including the pan and the air delivery and air return passages, through which heated air is confined to flow from the air delivery passage to the air return passage, and flowing heated air down through the air delivery passage into the pan, through the pan, and thence up and out of the pan through the air return passage, with substantially all of the heated air exiting from the lower end of the air delivery passage flowing through the pan and over and around the food in the pan and thence up and out of the pan through the air return passage. ### Claim 2 (depends on 1) The method of claim 1 wherein the pan is a one-time use disposable pan of paper or the like of relatively low thermal conductivity, the pan having a handle, the handle being out of circulation of the heated air and remaining cool for handling the pan, and wherein the pan is used, following the heating, as a plate for serving the food, and is then disposed of. ### Claim 3 (depends on 1) The method of claim 1 wherein the air flows through the pan at a velocity of above 1000 feet per minute as it impinges on the food in the pan and at a temperature above 425.degree. F. as it impinges on the food in the pan, with the air so spread and directed relative to the food that substantially all the exposed surfaces of the food are substantially simultaneously contacted by the air for rapid heat transfer to rapidly heat the food, solely by the air, to a state for being eaten. ### Claim 4 (depends on 3) The method of claim 3 wherein the pan is a one-time use disposable pan of paper or the like of relatively low thermal conductivity, the pan having a handle, the handle being out of circulation of the heated air and remaining cool for handling the pan, and wherein the pan is used, following the heating, as a plate for serving the food, and is then disposed of. ### Claim 5 (depends on 3) The method of claim 3 for heating a serving of partially or fully precooked french fried potatoes supplied in a refrigerated or frozen state wherein the air is blown on the potatoes at a velocity of from about 1500 F.P.M. to 2000 F.P.M. and at a temperature from above 425.degree. F. to 525.degree. F. as it impinges on the potatoes, and heats the potatoes to said state in less than about 75 seconds. ### Claim 6 (depends on 5) The method of claim 5 wherein the pan is a one-time use disposable pan of paper or the like of relatively low thermal conductivity, the pan having a handle, the handle being out of circulation of the heated air and remaining cool for handling the pan, and wherein the pan is used, following the heating, as a plate for serving the potatoes, and is then disposed of. ### Claim 7 (depends on 3) The method of claim 3 for heating a serving of partially or fully precooked french fried potatoes supplied in a refrigerated or frozen state wherein the air is blown on the potatoes at a velocity of about 1800 feet per minute and at a temperature of about 475.degree. F. as it impinges on the potatoes for about 50-70 seconds. ### Claim 8 (depends on 7) The method of claim 7 wherein the pan is a one-time use disposable pan of paper or the like of relatively low thermal conductivity, the pan having a handle, the handle being out of circulation of the heated air and remaining cool for handling the pan, and wherein the pan is used, following the heating, as a plate for serving the potatoes, and is then disposed of.