GB891870A - Improvements in or relating to counter-current horizontal-axis concrete mixers - Google Patents

Abstract

891,870. Concrete mixers. RICHIER S. A. Nov. 11, 1960 [March 9, 1960], No. 38769/60. Class 86. A concrete mixer comprises a horizontal rotary drum 1 reversibly driven by a motor and reduction gear 5, 6 and divided into two compartments A, B by helical baffles 16. There are rotating stirrers 11 mounted on a shaft 7 and driven at constant speed by a motor 13, at the same angular velocity as that of the drum, so that when rotating in the same direction the stirrers are stationary relative to the drum. A hopper 20 is raised on a track 22 by a motor 21 and has compartments for cement, sand and coarse aggregate which are released through gates 23, 24, 25 respectively. Water is supplied by a metering device 17 to a sprinkler 18. In operation the drum is first rotated in the direction C and the stirrers 11 in the counter-direction D, and the hopper 20 hoisted to the solid line position, Fig. 1. Cement is released to the shoot 19. and mixed with water in compartment A to form a grout. Gate 24 is then opened to release sand which is mixed with the grout to form a mortar. On completion, the direction of rotation of the drum is reversed as at C<SP>1</SP> and the helical baffles 16 transfer the mortar from compartment A to compartment B. The hopper 20 is then raised to the chain-dotted line position, the gate 25 opened and coarse aggregate discharged into compartment A whence it is transferred by the helical baffles 16 to compartment B and mixed with the mortar. Finally the direction of rotation of the drum is again reversed whereupon the helical baffles 15 discharge the prepared concrete. In another embodiment, Fig. 4, the drum 1a rotates in one direction only and the stirrers 11 in counter-rotation thereto. There are two loading hoppers 20a, 20b, for sand and cement and for coarse aggregate respectively, the latter discharging direct into compartment B. Materials are transferred from A to B by baffles 32 and a tilting shoot 16a, which is connected by a rod 35 with another tilting shoot 30, the latter combining the functions of loading shoot for the coarse aggregate and of discharge shoot for the concrete. In a modification, Fig. 5, the shaft 7 carries stirring blades 11 and helical baffles 36 which in one direction of rotation of the shaft 7 direct the materials towards the stirrers 11 and in the other transfer them into the compartment B.