US Patent 7871559 Inspection hole structure for flash-smelting furnace

An inspection hole structure 1 forming a furnace inspection hole 2 installed on the reaction shaft ceiling 104 of a flash smelting furnace, comprising a lower-stage water-cooling jacket 3A having an opening 3Aa at the center; an upper-stage water-cooling jacket 3B which is connected integrally to an upper part of said lower-stage water-cooling jacket 3A and forms said inspection hole 2 at the center in cooperation with said lower-stage water-cooling jacket 3A; and a bottom cover water-cooling jacket 4 provided in said lower-stage water-cooling jacket 3A to open or close said opening of said lower-stage water-cooling jacket 3A.