| 摘要 |
Equipment for initial sepn. and grading of sand and/or gravel particles prior to recombination to a desired compsn., comprising a collection device (I), e.g. a sand suction/vacuum unit or bucket system for pref. wet sand and/or gravel, a sepn. device (II) and a discharge unit (III). The collected material is first deposited onto a stationary sieve (2) where it is sepd. into two parts one having a particle size greater than 2 mm (W) and one less than 2 mm (O). The larger debris (8) e.g. clay, pieces of wood and particles greater than 8 mm is then sepd. out and e.g. disposed of. The sand and/or gravel streams are progressively graded into a number of particle streams (B,C,D,E) having size-ranges K = 2-8 mm, M1 = 1-2 mm, F1 = 0.25-1 mm, and F2 = 0.1-0.25 mm which are then collected in buffer stores (5,13,17,22). Measuring and dosing equipments (24,14,18,23) are used to supply the required particle sizes in the required quantities to belt conveyors (25,26) to achieve the required mix determined in the discharge unit (III) by the central control system (27).
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