| 摘要 |
A method of and apparatus for sorting pieces or particles of radioactive ore where the particles are moved one after another substantially horizontally then discharged into a gravity-accelerated trajectory which is substantially free-fall but can be controlled to follow a modified path by a low-friction slide plate. The falling particles pass a plurality of radiation detectors arranged in line along their path with increasing velocity due to gravity providing the required separation of the pieces so that each detector is subject to the radiations of essentially only one piece at a time. The size and number of detectors and the path length covered by the detectors is determined by the size of the pieces and the cut-off grade and accuracy required. All counts corresponding to a particular piece and derived successively from the plurality of detectors are accumulated since accuracy increases and percentage of probable error decreases with increased total count. The position and velocity of each piece are determined during their fall to provide close tracking of the particle's path in space and time. If the pieces are sufficiently closely sized the decision to accept or reject a particle may be made on the basis of total accumulated counts being greater or less than a preset figure. If the pieces are not closely sized then the size of each particle is also determined and used in a counts/time/size computation which is compared with set cut-off grade data to provide a decision to accept or reject the particle. |
