Accession Number : ADD006876

Title :   Low Frequency Hydrophone.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Cini,Hector J ; Meyers,Theodore J

Report Date : 11 Dec 1979

Pagination or Media Count : 5

Abstract : A pressure-balanced hydrophone having a low cut-off frequency which includes a pair of piezo-ceramic tubes, wired in series, and having one end of each tube secured to a metal block in the center. The second end of one of the ceramic tubes is covered by means of a solid metal end cap and the second end of the other ceramic tube is covered by a porous sintered metal end cap. The unit is enclosed in an elastomeric cylindrical boot which is closed at the open end by a metallic disc. A pair of fill plugs are provided to fill the interior and the exterior of the piezo-ceramic tubes with a suitable oil. The unique feature of subject device is that a plurality of pores in the porous sintered metal end cap act as a plurality of capillaries for pressure balancing and thus make the hydrophone insensitive to hydrostatic pressure variations. (Author)

Descriptors :   *Patents, *Hydrophones, Low frequencies, Pressure, Piezoelectric materials, Ceramic materials, Tubes, Oils, Porous materials

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE