WERKWIJZE TER BEREIDING VAN EEN OPGEKLOPT KWARKPRODUKT

740,111. Steam boiler steam and water drums; steam separators. BABCOCK & WILCOX, Ltd. Jan. 5, 1954 [Jan. 6, 1953], No. 291/54. Classes 123(2) and 123(3). In a high-pressure water-tube boiler, contaminants such as silica are removed from the steam by purifying apparatus located in the steam and water drum 10, the steam-water mixture from the generating tubes 11 entering a collecting chamber 14 in the drum and flowing therefrom through guide ducts 21 which lead the steam tangentially into separators 22 of the centrifugal type, for example as described in Specification 562,793. The bulk of the water separates from the steam in the separators and flows into the main body of water in the drum through openings 23. The steam flows upwardly in each separator through a perforated plate 26 and then into and through a scrubber 30 which consists of a number of closely spaced corrugated plates 31 the surfaces of which are covered with a moving film of pure wash water, for example, condensate, which is supplied from an external source via a pipe 42, a reservoir 41 and serrated distributer plate 54. The contaminants in the steam are absorbed by the wash water, the clean steam passing into a space 65 which is separated from the steam space 66 of the drum by plates 60, 61 and 62 so that admixture of impure steam from space 66 with the clean steam is prevented. The clean steam discharges through outlet pipes 12. To allow the steam space 65 to be vented when the safety valves, which are attached to pipes 67 located at the ends of the drum and communicating with space 66, open, a water seal, which breaks when the valves open, is provided between the spaces, the seal consisting of a trough 55 receiving the wash water draining from scrubber 30 and into which dips the lower edge of plate 62. Specification 726,970 also is referred to.