Improvements in and relating to methods of ultrasonic investigation with wide-band frequency modulated waves

摘要

673,447. Supersonic inspection devices; electric measuring systems. BRITISH THOMSON-HOUSTON CO., Ltd. April 24, 1950. [April 30, 1949] No. 10036/50. Drawings to Specification. Classes 40 (i) and 118 (ii). Relates to methods of investigating the properties of a liquid-which are dependent on the propagation velocity v of supersonic waves in the liquid. According to the invention, the liquid to be investigated is confined in a container having a fixed lateral dimension a and supersonic waves are transmitted into the liquid from one side of the container, the frequency of the waves being cyclically varied over a wide band # f and means being provided for measuring the number of resonances n produced during each cycle where n = 2a#f/v. The latter means may comprise an electromechanical transducer coupled to either side of the container and connected via an amplifier and rectifier to the Y plates of a cathode-ray tube whose horizontal time base is synchronised with the frequency variation, Fig. 5 (not shown), the resonance points being indicated as peaks on the resultant trace, Fig. 4 (not shown). The transmitting and receiving transducers may be X-cut quartz crystals and the frequency variation is preferably sawtooth. The invention may be applied to determining the relative proportions of a mixture of liquids in a chemical process, a change in the proportions being indicated by a change in the number of resonance peaks and polymerisation of the liquids being indicated by a change in the amplitude of the peaks. Specifications 628,116 and 628,170 are referred to.