GB755823A - Method of and apparatus for finely dividing materials or producing very finely divided stable and intimate mixtures - Google Patents

Abstract

<PICT:0755823/III/1> <PICT:0755823/III/2> <PICT:0755823/III/3> <PICT:0755823/III/4> <PICT:0755823/III/5> Finely divided intimate mixtures such as dispersions, suspensions or emulsions, are prepared by passing the constituents of the mixture whilst they are being moved in a radial direction under centrifugal force through a system of narrow gaps and alternating enlargements. The system may be formed by one or more series of opposed registerable cavities arranged on concentric orbits on opposed horizontal plane surfaces at least one of which is rotatable. Alternatively, the material to be treated my be passed between horizontal plane surfaces at least one of which rotates, the surfaces being provided with concentric series of substantially vertical tappets, the space between adjacent opposed series of such tappets constituting the narrow gap and the enlargement being formed by opposed cavities cut in each of the tappets where they face those of the series of tappets co-acting therewith. The latter system is exemplified in Figs. 2 and 3 where material to be treated is fed through a central hole 4 in a stator 2 which co-operates with a rotor 1, the stator and rotor being provided with a series of tappets 21, 22, and 11, 12 13 and 14 respectively. As shown in plan in Fig. 3 the material under treatment flows radially outwards through the channels formed between tappets 11, 12, 13 and 14. The opposed surfaces of the stator tappets 21, 22 and those of the rotor tappets 11, 12, 13 and 14 are each provided with recesses b and a respectively whereby the material is alternately expanded and compressed as the tappets of the rotor and stator move from the position of complete registration with each other to complete displacement as shown in Figs. 4, 5 and 6, the system of alternating gaps and enlargements is formed by two horizontal plane insert rings 15 and 24 provided with a series of cavities a and b, the rings being mounted on the rotor 1 and the stator 2 respectively. Material under treatment is fed to hopper 4 and passes radially outwards through the conical space formed between the stator 2 and the rotor 1 where it is subjected to the action of plain tappets 11, 12 and 13 attached to the rotor and similar tappets 21, 22 attached to the stator, and then enters the dispersion stage constituted by the co-acting rings 15 and 24. The mixture then flows through an annular cavity 14a, the lower part of which is provided with co-acting teeth 14 and 23 attached to the rotor and stator respectively whereby the material circulates in the cavity 14a and is repeatedly subjected to the action of co-acting teeth 14 and 23 before passing through a narrow vertical gap formed between the shoulder of the rotor and the rim of the stator. The material then passes through a further dispersion system constituted by opposed horizontal insert rings 16 and 25 attached to rotor and stator respectively, and each provided with a series of cavities a and b. If desired both horizontal plane surfaces carrying the cavities or co-acting tappets may be movable in opposite directions or in the same direction at different speeds, it being preferred that the frequency of the alternation of compression and expansion of the material treated occasioned by the action of the cavities formed in the insert rings or in the co-acting tappets, is ultrasonic. The materials being treated may be mixed with a liquid or with an inert or reactant gas and to increase the disintegrating effect of the apparatus, highly cooled or frozen substances may be admixed with the material to be treated. Specification 755,822 is referred to.