GB304036A - Improvements in and relating to submarine sound signalling or indicating apparatus - Google Patents

Abstract

304,036. Ryan, C. P. March 28, 1916. 1927. Detecting subaqueous sounds. - Apparatus for detecting subaqueous sounds comprises a hydrophone or magnetophone connected to a, diaphragm mounted in a streamline casing attached to a buoy or vessel, the mounting of the diaphragm being such as to eliminate water noise. The diaphragm 9, Fig. 3, is mounted in a heavy ring or two heavy rings with packing between, the ring being of such mass that its own vibrations do not affect the diaphragm, the latter being selected of a natural frequency between that of the low and high frequency water noises. The casing 8 is of stream line form and is carried from a buoy 1, Fig. 1, provided with a directing vane 7, the leads from the microphone passing through the mooring cable 2 clamped in an anchored coupling 3. To avoid water noises from the cable, rubber block grips are provided in the brackets 6 through which the cable passes. A hammer 10, Fig. 3, to tap the microphone to prevent packing is operated from the armature of a magnet 11, one terminal of which is earthed, the other being connected through a condenser to the cable so as to permit of actuation by a magneto at the observer's station, Instead of a microphone, a magnetophone may be employed, the diaphragm 9', Fig. 4, which may be the cover of a buoy, being attached by a clamp 16 to a reed 12 clamped a.t 13 to a permanent magnet 14, the pole-pieces of which carry coils 17 and are in proximity to the free end of the reed. The casing 8 of the diaphragm may be attached to a ship. In a modification the diaphragm directly receiving the vibrations may be fitted in the buoy or vessel and connected to the diaphragm of the magnetophone. fitted inside the buoy by a light spring-tensioned chain or flexible member.