| 摘要 |
A refractory sheet is coated by spraying it with a plurality of sprays of a dispersion of a hydrolysable metal compound, the sheet being heated to a temperature sufficient for the dispersion to form a metal oxide film thereon but below the temperature at which the sheet becomes molten, and providing paths of relative motion between the sprays and the sheet, in which the sprays are discrete and divergent <PICT:0862574/III/1> with respect to each other, each spray intersects a separate portion of the sheet at any given instant, and the separate sprayed areas are disposed transversely of the axis of parallel paths of relative movement between the sprays and the sheet, to cause the paths of relative movement of the respective separate sprayed areas to intersect and to combine to form a continuous transversely extending film. The base coated may be of various types of glass, of mica, stone, marble, china, porcelain, tungsten carbide, tungsten, or aluminium oxide. Many suitable metal compounds including silicon compounds are listed as suitable spraying materials. Apparatus comprises a furnace 11 for heating the sheet, a spraying station 20 comprising a plurality of spray guns 28, 30, 32, conveyer means 14, 16 adapted to support the sheet in a fixed plane and to translate the sheet 18 through the furnace and the spraying station along a defined path, a support post 22 for supporting the guns in adjustable relation along the conveyer means and means for supporting the guns in diverging relation to each other. The middle gun 30 may be directed horizontally, the upper and lower guns 28, 32 being directed upwards and downwards respectively, and being spaced apart horizontally from the middle gun in the direction of the conveyer. The rates of spraying and the compositions of the liquids supplied to the guns may differ. Specification 724,086 is referred to. |
