GB347022A - Improvements in methods for the observation of the speed of a vessel by directed beams of ultra-audible waves - Google Patents

Abstract

347,022. Measuring speed of a ship acoustically. CHILOWSKY, C., 15, Rue du Lunain, Paris. May 9, 1930, No. 14345. Convention date, May 11, 1929. [Class 106 (iii).] Acoustic speed indicators.-The speed of a vessel is measured by observing the Doppler effect when beams of ultra-audible waves directed obliquely towards the bottom of the sea are reflected therefrom, the frequency of the echo waves being measured by a piezo-electric wave-meter which may be graduated for direct reading. A great number of resonators having distinct frequencies are used. In the preferred form these consist of quartz or other piezo-electric crystals. These are mounted in an alternating current field affected by the reflected waves. Different resonators will be affected according to the speed of the vessel and as each is arranged in the path of a beam of polarized light which is regulated to extinguish light by means of compensators and an analyser, when one is resonated a spot of light is allowed to emerge. In one form these quartz plates are arranged in a circle and surrounded by a fixed scale adjacent which the spot of light may be read, and the speed indicated. To compensate for pitching and rolling of the vessel, the scale is moved about the centre of the circle of quartz plates by a gyroscope. In a second form a large number of plates are disposed between two coatings in a tube containing rarefied gas in which is an electrical field under which circumstances a luminous spot is produced when a crystal vibrates. Specification 227,788, [Class 118 (ii), Signals], is referred to.