THE “ELECTRIC” EYE

Wanganui Chronicle, Volume 72, Issue 105, 4 May 1929, Page 17 (Supplement)

THE “ELECTRIC” EYE

A MODERN INVENTION APPLICATIONS EXPLAINED A spectacular demonstration of the uses of the photo-electric cell, the socalled “electric eye” and other vacuum tube devices was given at the annual dinner meeting of the American Institute of Electrical Engineers at New York, N.Y., U.S.A., in February. John V. Breisky, of the Westinghouse Electric and Manufacturing Company, talked on “Photo-electric and Glow Discharge Devices and their Applications to Industry,” and demonstrated apparatus which, by means of various vacuum tube devices act with superhuman accuracy and dependability in such varied functions as detecting and instantaneously extinguishing fires, counting people or passing objects of any size, automatically sorting materials according to colour or imperfections, or providing safety against explosions in gas and oil furnaces. A lighted match was thrown into a tank of gasoline and kerosene on the lecture platform. The first cloud of smoke from the tank instantly operated the “photo-electric smoke detector,” which in turn automatically released carbon dioxide from a cylinder and extinguished the fire before the audience could realise what had happened. Mr' Breisky showed the superiority of this ' method of protection against fire as | compared with previous methods which were dependent upon a change in temperature before operating. Quickstarting fires were often widespread before extinguishing means were released. Persons coming into the lecture hall were counted automatically as they crossed a beam of light which extended across the entrance. There was no need to “press the button” or for actual physical contact, for a photoelectric cell set into operation an electrical counter every time the ray of light was interrupted. Mr Breisky pointed out how apparatus of this type may be used for toll bridges, vehicular tunnels, or turnstiles, and for the counting of items in mass production, or detecting paper breaks in mills where machinery must be stopped instantly to prevent accidents. Mr Breisky brought out that the advent of radio, talking movies, and television had been an enormous stimulus to an intensive study of vacuum tube devices, resulting in the invention of new tubes and improvements of others. The Westinghouse Company soon realised that those devices must have many other uses and therefore put much research and engineering talent on devising new means of applying them. These studies resulted in opening up new fields for their use in industry during the past two years.

Where arduous tasks of sorting have heretofore been dependent upon the easily wearied human eye, a mechanical process may now be substituted, thus releasing many workers for less monotonous tasks. More accurate than the human eye, the photo-electric cell responds equally well day or night, in hot or cold weather.

The use of the jihoto-electric was also demonstrated. A spot of light was made to fall on the surface under examination and reflected from the sur face to the photo-electric apparatus. Small packages of supposedly uniform character were automatically moved past this spot of light. If one of them was without a label or was otherwise defective, it was automatically thrown out.

Mr Breisky spoke of a similar device which is applicable to the automatic inspection of wide surfaces such as metal sheets that should *be of uniform character, or in selecting paper for defects, analysing colours to match fabrics, paints, tiles, etc. All this is now done by the eye, but the electric eye presents a more scientific and precise method.

Another interesting demonstration showed how domestic oil and gas furnaces can now be protected against explosions. Heretofore the flow of gas or oil could not be stopped quickly enough when, for any reason, the flame was extinguished. The so-called grid glow tube acts instantly and with absolute dependability in such cases. By the amplifying of impulses a relay and connected apparatus are made to function so that a variety of operations may be caused through the activity of this tube, which can be motivated by as little energy as one millionth of a watt. The amount of energy necessary to light a 75 watt lamp is 75 million times as much. For the invention of this tube, D. D. Knowles of the Westinghouse Research Laboratories was awarded the John Scott medal of 1927.

The grid glow tube is also applicable as protection against theft, since it will act instantly when anyone approaches it. Thus there may be installed inside a safe a device which will ring an alarm or trap an intruder. The approach of a hand is enough to effect this sensitive piece of apparatus which through relays will operate any kind of apparatus connected to it. Window or counter displays of many sorts may bo set in motion by a passerby without actual contact.

Concluding his talk, Mr Breisky pointed out that the application of these sensitive devices for automatic control is still in its infancy. Remarkable things have been achieved in the last few years, but the future holds many more. Many processes and methods now used in factories, mines ’and mills will be revolutionised, and human beings will be released from arduous tasks that should rightfully be performed by robots in this age of mechanisation.