GB477139A - Improvements in and relating to the detection of faults in solid, liquid or gaseous bodies - Google Patents

Abstract

477,139. Measuring intensity of sounds. SOKOLOFF, S. May 13, 1937, No. 13509. [Class 118 (ii)] [Also in Group XIX] Comprises a process for detecting faulty places in solid, liquid, or gaseous bodies by ultra acoustic oscillations produced by piezo-electric means and directed through the body which oscillations on emerging from the body excite a piezo-electric crystal plate to produce a potential difference characterized in that the distribution of electric charges on the plate is analysed by known television means and transformed into a visible or graphic picture by television reception. The body 1 with faults 5 to be detected has bearing against it a quartz plate 2 excited by a high frequency generator 6. The ultra-acoustic rays 4 traverse the material except where cut off by the faults 5 and in turn excite a quartz plate 3 producing a non-uniform distribution of electric charges on the plate. Bearing against the plate which on this side is wetted with oil is a Braun tube 7. The side of the plate 3 next the body is coated with finely powdered metal. The inner or outer surface of the Braun tube is covered with a network of fine electrodes 8 insulated from one another similar to the light-sensitive mosaic in the television system of Zworykin. The charges of the individual electrodes at the end of the tube can be taken off by a thin electron pencil 9. If the pencil 9 be deflected in the usual way in two directions at right-angles, the distribution of the charges can be transmitted to the receiving device proper in the form of a cathode tube with a phosphorescent screen. In a further construction, at the inner end surface of the Braun tube a light sensitive mosaic is distributed, a network of fine electrodes being applied to the piezo-electric mosaic lying at the same time against the outer surface. The fine electrodes receive the charges which control the electrons emanating from the photo-mosaic. Again, the quartz plate or the body may be moved in two directions at right-angles and the intensity of the piezo-electric charge fixed in each point. In this case the quartz receiver is as small as possible.