SELF-CLEANING COOKING APPARATUS

1,232,551. Enamels for self-cleaning ovens. FEDDERS CORP. 5 Jan., 1970 [13 Jan., 1969], No. 493/70. Heading C1M. [Also in Division F4] A catalytic enamel lining for a cooker comprises a first ceramic layer bonded to the walls and having a surface remote from the wall containing an oxidative catalyst effective above 275‹ C. for the destruction of food soil and with a rough toothed finish, and a second layer of catalyst mechanically bonded to the surface, each layer of catalyst including a high temperature binding agent. The cleaned metal walls, which may be of iron, steel, a chromium-nickel alloy, aluminium or one of its alloys, is coated with a porcelain frit which is dried to a bisque, and a slurry comprising 49À5-60À5% by weight of catalyst, 33-40% water, 0À86-1À1% of high temperature binding agent (in final form) and 1À25-1À5% of wetting agent is applied. The walls are fired at a temperature of 1000- 1800‹ F. to fuse the bisque layer. A second layer of catalyst slurry is applied and fired at a temperature sufficient to form the high temperature binding agent. The catalyst may be an oxide, cerate, manganate, manganite, chromite, chromate or vanadate of cobalt, nickel, ruthenium, palladium, platinum or a rare earth metal or a mixture of rare earth oxides. The wetting agent used may be glycerol or another polyol or any detergent that does not prevent the formation of the high temperature binder or the catalytic action. The high temperature binder may be titanium dioxide, formed from titanium lactate added to the slurry, or silicon dioxide formed from sodium silicate in the slurry. The water used to form the slurry is distilled or de-ionized, and the slurry is applied by an airless method. The ratio of active catalyst to high temperature binder in the finished coating is between 45:1 and 70:1 by weight.