GB127560A - Improvements relating to the Mixing of Cement and Apparatus therefor. - Google Patents

Abstract

127,560. Johnson, N. C. May 29, 1918, [Convention date]. Mixing-apparatus.-In a method of mixing cement and water in batches, with or without other ingredients, the material is subjected in a container to centrifugal force so as to produce high-velocity mass flow of the batch and cause it to circulate rapidly in a steady continuous stream along one or more paths rapidly changing in direction, thereby causing the particles to be compacted together with interparticle attrition. The attrition is sufficient to raise the temperature of the mass substantially and without substantial areation thereof. As shown, the concrete-mixer consists of a vertical mixing-bowl 1, Figs. 1 and 2, with outwardly-curved flaring walls and mounted by means of a central projection 8 on a stationary shaft 9, on which it is rotated so as to have a peripheral speed of about 1500 feet per minute by worm gearing 16, 24 from a shaft driven by a motor 22. The bowl preferably consists of a bottom section 2 and a number of upper sections 3 secured to each other by butt-straps 6, and to the section 2 by bolts 7. The abutting edges 5 of the sections 3 are preferably shaped so as to fit obliquely. The shaft 9 is secured to the base 10, and a nut 12 prevents the bowl from moving upwards, a protecting-cap 13 secured by bolts 14 to the projection 8 enclosing the nut and upper end of the shaft. A stationary guard-ring 25 bolted to uprights 26, Fig. 5, is provided for the rim of the bowl. The stationary defecting and mixing blades 27 are each carried by an arm 32 pivoted on an upwardly-extending pin 31 on a member 29 secured to a lateral boss 28 on the upright 26. The outer portions of the blades are formed as hardened sections 45 secured to the body portions by screws 46. The inner face 47 of each blade is preferably curved along its .length as well as across its width, and is inclined forwardly and inwardly against the direction of flow of the material. An upturned flange extends along the upper edge of each blade. One of the blades can be tilted by means of a handle 38, and a discharge blade 40, with its inner end 43 curved upwardly, is arranged behind the tilting blade and carried by a curved arm 41 bolted at the lower end to the upright 26 which carries the tilting blade. The blade 40 directs the mixed material over the side of the bowl into a shoot 44, but is shielded by the tilting blade during the mixing operation. A single mixing or deflecting blade may be used.