GB779013A - Improvements in classifying apparatus for sand commonly called sand cones - Google Patents

Abstract

779,013. Washing granular material. FLOATEX SEPARATIONS, Ltd. Feb. 23, 1955 [Feb. 23, 1954], No. 5340/54. Class 82(2) Classifying apparatus for sand or the like comprises a tank 2, Fig. 1 (corresponding to Fig. 2 of Specification 696,300 to receive the sand suspended in water, a partition in the form of a weir 4 extending from below the normal water level to the bottom of the tank to divide it into two compartments, an inlet opening 7 to the upstream compartment 5 at a position remote from the partition, a weir 14 and an overflow launder 8 at the end of the downstream compartment 6 remote from the partition, a horizontal plate 21 extending across the tank and along the upstream compartment 5 except for a gap at the downstream end, an upward extension 23, at the downstream end of the plate 21 and terminating level with the top of the partition 4, a continuation 24 sloping backwards at 30 degrees to the horizontal, and a connection from each compartment to a dewatering cone (not shown). Coarse, medium and fine sand may be obtained from cones 36, 44, 45 respectively, Fig. 4, fed from two tanks 27, 31, arranged in series. In each tank the partition 26 is in line with the upstream wall of the downstream compartment. The suspension falling through gap 26a into compartment 28 is discharged into the boiling box 30 of the second tank 31 together with the overflow water from tank 27 at 61, while the suspension from compartment 29 is discharged into the downstream compartment 37 of the second tank 31. Suspension falling through gap 26b into compartment 32 is discharged at 35 into the first cone 36. Suspension passing over the gap 26b is divided into two parts by a separating wall 40, 41, Fig. 5, which partitions off, in the manner shown, a portion of the compartment 37 leading to an outlet 42 for medium sand suspension, and a portion leading to an outlet 43 for fine sand suspension. In the modified tank of Figs. 7 and 8 flow is from the left, the separating wall 40, 41 of Fig. 5 is located in the upstream compartment 51a, and the outlets 49 and 50 correspond to outlets 42 and 43 respectively. The plate corresponding to the plate 21 is divided longitudinally into two parts 46, 47, Fig. 7, each separately adjustable in the flow direction to vary the width of the gap. The part 41 of the separating wall is extended upwards at 48, Fig. 8, into part 46a of the gap. so that coarser suspension flowing down to the left of it passes out at 49 while that flowing down to the right of it passes out at 50 together with the suspension flowing through the part 47a of the gap. Finer suspension passing over the partition 4 flows into the second compartment 51 and leaves at 52. In Figs. 9 and 10, not shown, there are two classifying tanks and four dewatering cones, the latter being arranged at the four corners of a square in plan. The three grades of sand are provided by mixing two of the four grades actually separated in the apparatus. Shoots leading from the dewatering cones may be pivoted so that any two adjacent cones may together feed a common stock pile.