GB1387742A - Apparatus for and method of drying and blending materials - Google Patents

Abstract

1387742 Mixing apparatus A C AVRIL 17 Jan 1972 2228/72 Heading B1C [Also in Division F4] The invention relates to a drying apparatus in combination with a blending apparatus of the type disclosed in United Kingdom Specification 1303033. The drying apparatus comprises a pair of tapered, parallel drums 1, 2 and a heating means as fully disclosed in the above mentioned Specification. Material passing from the drying apparatus is deposited in hoppers 3, 4 from which it passes to the blending apparatus. The blending apparatus A comprises at least one blending unit 8, 13, 14, the need of which comprises a receiver element 11 in the form of an open-topped truncated inverted cone. The truncation forms a circular discharge opening 76 which has a diameter equal to at least one third of the diameter of the open top of the truncated cone. An upright discharge control cone 12 having material dispersing rods 80 projecting therefrom is disposed within the lower portion of the receiver 11 for closing the discharge opening 76 in one of its two positions. In its other or elevated position the control cone 12 allows material to fall from the blending apparatus through a split into a bag 10 or into a succeeding blending unit. The control cone 12 has a sealing ring adjacent its base, which ring is either clamped on the cone (as shown) or held on the base of the cone by a retainer ring (Fig. 14 not shown). The cone 12 is actuated by a reversible pneumatically operated piston and cylinder device 88, the cylinder thereof being mounted on a spider 94 connected to the wall 72 surrounding the receiver element 11. As shown the blending apparatus is in three sections and is used for mixing sand, aggregate and cement. The first blending unit 8 is fed with cement by a feeder 6 and with sand and aggregate by a feeder 5 from two hoppers 3, 4, the sand and aggregate having been separated at the discharge end of the drying apparatus by a screen 40. The blending unit 8 is suspended from a weighing apparatus by rods and bellcrank levers (Fig. 3, not shown) so that predetermined quantities of cement, and sand and aggregate (in that order) can be fed thereto. The intermediate and lowest blending units 13, 14 are supported by a floor 109 of the apparatus. Flow of materials into and through the blending apparatus is controlled electrically, bagging being controlled by a manually operated push button. In an alternative blending apparatus all the units are rigidly supported and hoppers feeding the uppermost blending unit are suspended from a weighing apparatus (Fig. 13, not shown).