Patent GB-983927-A (GB)
Title: Improvements in means for automatically determining the individual degree of radioactivity of a plurality of bodies
IPC: G01T7/08
Filed: 1962-04-19
Abstract: 983,927. Automatic radiation - measuring apparatus. E. K. COLE Ltd., W. E. THOMPSON, and W. H. LEGON. April 19, 1962, No. 15173/62. Heading H5R. Radio-active samples to be tested are placed in a series of containers 6 (Fig. 1) spaced equidistantly along a conveyer chain or belt 1, which is given an intermittent movement so that each container is brought in turn opposite a chamber 7 containing a radiation - measuring device; mechanical means lift the sample from the container and move it into the chamber for the radiation measurement to be made, and then transfer it back to the container. The detector may be a photomultiplier tube, used as described in Specification 859,281. If the count is too high, the counter may be automatically adjusted to a lower total, so that widely different amounts of radioactivity may be dealt with. A zero indicator 9 may be provided, which switches off the apparatus after a given number of samples have been tested. Fig. 3 shows the mechanical arrangement for handling the samples. A grab 14 is carried at one end of a shaft 13 mounted in guides 13a, rotation of the shaft causing the grab jaws to open and shut. This is controlled by a cam plate 18 supported from toggle levers 20 having fixed pivots at their upper ends. A lever 22 turning on a fixed pivot 23 has a stud 24 extending through a slot 25 in plate 18, and the lever extends into a vertical limb 26 which can engage a cam 27 on shaft 13. The mechanism is actuated by a stud 15 on one of the links of a chain 16 which is motor-driven round a number of guiding sprockets. The plate 18 has two shaped cam edges 18a and 18b at opposite sides. As the movement of the chain causes stud 15 to bear against cam edge 18a, plate 18 is swung to the right, and limb 26 is tilted upwards to engage cam 27 and so rotate shaft 13 to open the jaws of grab 14, until stud 15 has moved clear of edge 18a, when the plate falls back into the rest position of Fig. 3. Similarly, as stud 15 moves down the other side to bear against edge 18b, plate 18 is swung to the left, again opening grab 14. Shaft 13 is mounted within a traverse arm 12, and the whole arm and shaft can be traversed to the right (as seen in Fig. 3) to move a sample held by the grab into the radiation chamber, and back again. This is effected by the stud 15 engaging the fork of a forked bracket 28 fixed to the arm 12 and carrying them along as the chain passes through the straight top portion of its path, so that the arm is now in extended position. It is retracted by similar mechanism arranged on the other side (not shown) of the bed plate 36. Further mechanism is provided to move the bed plate 36, and all the mechanism mounted thereon, in an up and down direction, as required. Thus in an entirely automatic sequence, the grab lifts a sample from its container 6, moves it into the chamber 7 (whose doors open in synchronism), places it on a suitable support therein, releases it, moves back to a retracted position, allowing the doors to close, and the radiation measurement to be made, moves into the chamber again to lift the sample out again, deposits it back in its container, and then repeats the whole sequence with each of the succeeding samples as each in turn is brought opposite the chamber 7.