| 摘要 |
1334147 Steam drying of filter cake in rotary filter ENVIROTECH CORP 1 Nov 1971 [30 Oct 1970] 50687/71 Heading B1D Filter cake, formed on a rotary drum or discs 14 in passing through a bath of slurry while subject to an interior vacuum applied through receiver 22, is dried by applying superheated or saturated steam thereto in the space above the slurry, the steam being drawn the slurry, where they are subjected to internal tions (Fig. 3, not shown), wherein all the steam is condensed within the cake so that the condensation front just reaches the filter medium on the drum or discs where the cake is removed therefrom, are maintained by varying the vacuum applied through receiver 22 and/or the rotational speed of the drum or discs. As shown, the temperature of gas drawn through receiver 24, which applies vacuum to the drum or disc sectors above the slurry surface, is monitored at 72 and automatically controls the vacuum in receiver 22, by adjusting valve 66, and the rotary speed, by variable speed drive (Fig. 2, not shown). Thus a rise in temperature at 72 indicating that steam is penetrating the cake increases the vacuum and the speed, restoring the status quo by increasing the thickness of cake building up and reducing the time for which the cake is exposed to the steam. In addition the rate of steam supply may be varied by valve 28, controlled either by sensor 72 or by a temperature monitor 37 in the upper part of the housing 18. Steam temperatures, and flow rates and cake thicknesses are exemplified. |
