Solid/liquid separation batch pressure filters

The saponification of organotriethoxysilane is carried out in enameled reactor 14 with an agitator and a water vapour jacket. First the reactor is filled from batch box 13 with 42% caustic soda and with a metered amount of water. After the dissolution is complete, the alkali solution receives organotriethoxysilane from batch box 12 at a temperature below 60 °C. The contents of the apparatus are agitated for 1 hour the mixture is sampled to determine the NaOFl content, solid residue and density. The prepared liquid is filtered through brass mesh in nutsch filter 15 into settling box 16. In the settling box the product is separated from mechanical impurities (it is settled for at least 24 hours), filtered in pressure filter 17 and poured into containers. 

The material to be filtered is fed into the vessel under pressure, and separation takes place with the solids being deposited on the leaf surface, and the liquid passing through the drainage system and out of the filter. Cycle times are determined by pressure, cake capacity or batch quantity. Where particularly fine solids must be removed, a layer of precoat material may be deposited on the leaves prior to filtration, using diatomaceous earth, Perlite, or other suitable precoat materials. 

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