Counting Newspapers, Foiling Burglars But Two Functions of Photo Electric Cell few of the manifold uses to which the photo electric cell, a marvellous invention of modern times, can be put, were described by Mr. W. Miles in a talk on "Photo Electric Cells before members of the Engineering Society of China at a meeting held yesterday evening at the Park Hotel. The meeting was held under the auspices of the Institute of Electrical Engineers, China Centre, and Mr. S. Flemons, chairman of the Institute, presided.
The counting of newspapers turned out at a tremendous rate by a huge printing press was one of the uses of this "wonder li" can be put described in the course of the lecture. Copies of the newspaper, as delivered by the machines, were automatically placed in five-quire bundles in close consecutive order yor belts, which carried r load at a rate of 120 feet per second throughout the length of the machine room to the dispatch department. Each bundle interrupted a ray of light directed on a photocell, and thus operated a relay in an amplifier circuit.
The apparatus enabled the printing overseers to remain in their offices fifty yards away from the machine room, and still to be in close touch with the progress of the presses. This method was typical of photo-electrical counting devices now used in a great many manufacturing plants. Its usefulness was not confined to counting the actual output, but arrangements could be made conveniently to record the extent to which the output was lacking. Multiple recording could readily be arranged by the introduction of a simple mechanical device to indicate the completion of sets of interrupt tions of the beam of light. High speed counting up to a rate of 1,000 per second could also be arranged.
Text read from the printed page and cleaned; old type leaves the occasional error.