GB192278A - Improvements in and relating to the hydration of lime and like reactions - Google Patents

Abstract

192,278. Knibbs, N. V. S., and Denny Chemical Engineering Co., Ltd. Jan. 30, 1922. Lime. - In the hydration of lime and similar reactions between a solid and a liquid, the variation in temperature of the reaction-mass is utilized to vary the rate at which one of the reacting materials, usually the liquid, is supplied. Lime entering the trough 1 from the conveyer 6 is treated with water delivered from the pipe 7 in such amount that the initial product contains an excess of lime, an auxiliary supply of water being then introduced from the sprinklers 11 at a rate which is made to vary with the temperature of the reacting mass. This is effected by means of a device comprising two rods 12, Fig. 5, of different metals. One rod is rigidly secured at one end to the end-plate 13 of the trough 1 and at its other end to the adjacent end of the companion rod, the free end of which passes through a gland 14 and is connected through a coupling with the rod 16. The rod 16 is adjacent to the perforated spindle 18, Fig. 3, which communicates with the chamber 22 to which water is supplied through the pipe 23 and needle-valve 30. Water discharges through the outlet 34 at a rate which varies with the distance between the adjacent ends of the rod 16 and spindle 18, and the resultant pressure in the chamber 22 acts by way of the duct 37 on a diaphragm or like device to control the supply of liquid to the sprinklers 11, the supply increasing with the temperature of. the reaction-mass. The spindle 18 is engaged in the support 20 by an external screw-thread, by means of which the supply of liquid to the sprinklers may be varied independently. The hydration of lime is preferably carried out at a relatively high temperature, an excess of water being used to ensure complete hydration.