GB846190A - Improvements in the mixing of flowable materials and apparatus therefor - Google Patents

Abstract

846,190. Mixing appliances. DU PONT DE NEMOURS & CO., E. I. Aug. 7, 1958 [Aug. 15, 1957], No. 25416/58. Class 86 [Also in Group XX] A method of mixing by bringing two (or more) centrifugally formed upwardly concave films into interfacial contact may be performed by means of vertically coaxial hollow inverted conical vessels 1, 2 rapidly rotatable by shafts 6, 8 driven by motors 7, 9 respectively. Fluid is supplied to vessel 1 from container 13 through duct 12 and to vessel 2 from container 14 through duct 15 and the hollow shaft 8. The fluid in vessel 1 flows in a thin film over the rim 3 (which is in close proximity to the inner surface of vessel 2) making contact with the film of fluid flowing up the wall of vessel 2. The mixed fluid flows over the rim 5 of vessel 2 into the container 17. A constructional embodiment of the apparatus shown diagrammatically in Fig. 1 is described with reference to Fig. 2 (not shown). The method is stated to be applicable to liquids, emulsions, dispersions, finely particulate solids and materials which can be rendered fluid by heating. In the case of liquids of different viscosity, the more viscous liquid is rotated at the greater speed. By using a suitable number of vessels more than two materials may be mixed. The rotating vessels may be cones, discs, cups or other suitably concave vessels; they may be provided with vanes or baffles, and the inner vessel may be perforated. The vessels may rotate in the same or (if turbulence is required) in opposite directions. The axis of rotation is preferably but not essentially vertical. The flow of materials may be automatically controlled by a characteristic of the effluent. The surface exposure of each material to the other may be increased by increasing the speed of rotation to reduce the thickness of the layers. The method and apparatus as well as being suitable for physical mixing are especially suitable for chemical reactions where the intimate contact between and constant concentration of reactants and defined area in which reaction takes place result in small particle size, suppression of unwanted side reactions and possibility of performing reactions which have critical reaction rates. The method and apparatus are claimed as especially suitable for the preparation of emulsions for photographic film, among other named uses.