Patent GB-1439971-A (GB)
Title: Food treatment apparatus
IPC: A23L5/10
Filed: 1973-05-09
Abstract: 1439971 Ovens HEAT & CONTROL INC 9 May 1973 [2 Feb 1973] 22226/73 Heading A2A [Also in Division A4] An oven 10 operating at substantially atmospheric pressure comprises an elongate housing 11, Fig. 1B, with top, bottom, side and end walls, a supply of process vapour in said housing, a partition dividing the housing into a vapour heating chamber 51 and a food processing chamber 41, the housing end walls 54, 63 having openings therein defining an inlet (15) Fig. 1A (not shown) and outlet 20, a power-driven conveyor 16 arranged to carry solid food through the processing chamber 41 and of steel wire construction which permits the process vapour to circulate through it, a gas burner 18 discharging into heating chamber 51, a power-driven fan 17 for circulating the process vapour, a baffle 62 directing the draft of vapour from the heating chamber 51 through the processing chamber 41 and thence back to the heating chamiber. Nozzles 19 may add steam or hot water to the atmosphere within the chamber. Cooling water is circulated through pipes 87 which support the conveyor and keep it cool. The framework of the apparatus comprises seven pairs of legs 22, including two lifting sections defining four hoists 23, made from tubing. Hoists 23 raise the upper housing 12 for the purpose of cleaning and maintenance, and in the closed position a water seal (31) Fig. 2 (not shown) is provided to retain the process vapour and act as an explosion release. In the lower shell 13 the bottom slopes from each end towards a pair of drain nozzles 32 to carry off into a manifold 33 juices, fats, etc. from the product. The oven 11 has generally a double skin wall which at the bottom portion 34 provides for the circulation of cooling water, and elsewhere is air filled for insulation. The oven is vented via double-walled stacks 58, each equipped with an exhaust fan (not shown). Air drawn into the oven, through inlet (15) or outlet 20 passes up flue 61. The stacks 58 are telescopic. The gas burner assembly 18 discharges a jet 66 of combustion gases into the heating chamber 51 to produce the process atmosphere, as indicated by arrows 21. The circulating fan assembly 71 is mounted in the upper shell 12 in nacelle 77, and stator vanes (83) downstream of the fan regulate the flow of the process atmosphere. A conveyor drive unit (91) arranged at the feed end is coupled to the drive roller (98) through sprockets (99) Fig. 5 (not shown) and (101) and chain (102). Conveyor speed and belt tension are adjustable, and a flap member 118 over inlet (15) and outlet 20 return the process atmosphere within the oven. A liquid spray system for cleaning the oven interior comprises nozzles 121 in both chambers through which cleaning solutions are circulated. Control of moisture content of the process atmosphere in the heating chamber includes a nozzle 147 spraying against a thermocouple 148 in duct 149 to provide a "wet bulb" temperature, the thermocouple being connected to a controller recorder 152 coupled to steam valve 153 for regulating a supply of steam to the nozzles 19. Similar control of oven temperature is achieved by thermocouple 151 coupled to controller recorder 172. Hot water may be used as an alternative to steam.