| 摘要 |
1,246,216. Sorting bodies according to their resistivity. COLONIAL SUGAR REFINING CO. Ltd. April 8, 1969 [April 10, 1968], No.17794/69. Heading G1N. Metalliferous ore is separated from barren ore by passing ore chunks down a trough formed by a pair of contrarotating rollers so that the ore chunks pass one at a time over a testing station in which they bridge an insulating portion 5 between two conducting portions 4, 6 of the rollers and are directed to bin 14 or 15 according to their electrical resistances. To increase the contact between the ore chunks and the rollers at the testing station, the rollers may be bulged out as shown and the sections 6, or 4, 5 and 6, may be rotated more slowly than, or in the opposite direction to, sections 3, which preferably rotate faster than sections 2. Insulating portions 5 may be of plastics resin or may be merely air-gaps. Measuring circuit. Brushes 21, 22, 23, 24 co-operate with slip rings (not shown) within roller sections 6. Comparator 28 delivers an output signal whenever the output from amplifier 27. exceeds a reference voltage set on 29. Photoelectric means (not shown) enable gate 31 when a chunk is at the testing station. A pulse analyser 32 evaluates the pulse pattern (due to intermittent contact between the chunk and the rollers).
|
