GB661599A - Improvements relating to the cooling of spray dried organic detergents - Google Patents

Abstract

<PICT:0661599/III/1> <PICT:0661599/III/2> Hot spray - dried organic detergent particles are introduced into the lower part of a cooling column 17 up which passes cooling air at an average velocity of less than 25 feet per sec. and the cooled particles which have passed up the column are separated from the air leaving the column. The hot particles are produced from an aqueous solution of detergent which falls from sprays 2 in a tower 1 to be dried by hot gas such as air flowing either up or down the tower. From the bottom of the tower the particles are conveyed by a stream of gas either through a cyclone separator 9, star valve or air lock 10a and surge hopper 14 to the air inlet duct 16 of the cooling column 17 or they may pass directly to the duct 16 as through an air lock 6b, e.g., a star valve. The stream of gas for conveying, i.e. atmospheric air from an inlet 8 or hot gas from the drying tower, is induced by a fan 13 to flow through a duct 7, the separator 9, a duct 11 and a filter house 12 from which the trapped fine particles are returned by a conveyer belt 58 for re-processing. The duct 11 also receives air from the outlets of a further separator 19 and a particle classifier 34 through which, in turn, the particles from the cooling column 17 are passed, being further cooled in the classifier. An air lock 20a is provided between the two structures. The classifier 34 consists of an inclined framework 36 vibrated by an eccentric at its upper end and carrying a housing connected at the top by ducts 44 to the exhaust duct 11 and containing an upper coarse screen 40, Fig. 3, and a lower, fine screen 41. Air is cooled in an intake 47, Fig. 1, and passes to manifolds 52 on each side of the classifier to be introduced between the sieve screens to cool the falling particles including those of the desired size which are caught on the fine screen 41 before discharging to packaging apparatus through an outlet 55, Fig. 1. Other outlets are provided for the too coarse and too fine particles which are returned for re-processing. Flexible connections 57 obviate the vibration of the inlets and outlets for air and detergent. Air in the classifier intake 47 is cooled by evaporators therein which are fed with liquid refrigerant from a compressor 28 and a water-cooled condenser 31 which also supply an evaporator 24 in the cooling air line to the column 17. This air line comprises also a positive displacement blower 22, compressor, or turbo-compressor, a water cooler 23 and a mist separator 25. Examples are given of working data for the plant concerning quantities of soap, rates of flow, temperatures and humidities.