Pressure sensitive hydrophone

Claim 2

A marine hydrophone for responding to sound pressure waves in water, including a radially polarized annular piezoelectric ring having inner and outer cylindrical surfaces concentric with the axis of the ring, means forming first and second electrodes on said inner and outer surfaces respectively extending over most of the area of the surfaces and electrical conductors connected to the respective electrodes for conducting away from the hydrophone electrical signals representative of strains produced in the piezoelectric ring by such pressure waves, said ring having annular end surfaces at the two opposite ends thereof, and a pair of thin circular diaphragms respectively covering the opposite ends of said ring having peripheral portions of the diaphragms secured to said annular end surfaces, said diaphragms being each permanently formed inwardly toward the axial center of the ring defining inwardly dished zones over the diaphragm portions located radially inwardly of said inner cylindrical surface.

Claim 3

A marine hydrophone as defined in claim 1, wherein each of said diaphragms includes an outer edge preformed into a short cylindriCal flange having an inner diameter slightly larger than the outer diameter of said ring and located in overlapping relation to a portion of said outer cylindrical surface of the ring.

Claim 4

A marine hydrophone assembly for an elongated seismic streamer designed to be towed under water, comprising a hydrophone unit including a radially polarized annular piezoelectric ring having inner and outer cylindrical electroded surfaces concentric with the axis of the ring, electrical conductors respectively connected to the inner and outer electroded surfaces for conducting away from the hydrophone electrical signals representative of strains produced in the piezoelectric ring by sound pressure waves in the water, said ring having annular end surfaces at the two opposite ends thereof, and a pair of thin circular diaphragms respectively covering the opposite ends of the ring having circumferential portions adjacent the periphery of each diaphragm secured to said annular end surfaces, said diaphragms being each permanently formed inwardly toward the axial center of the ring defining inwardly dished zones substantially throughout the diaphragm portion lying radially inwardly of said inner cylindrical surface.

Claim 5

A marine hydrophone assembly for an elongated seismic streamer designed to be towed under water, comprising a hydrophone unit including a radially polarized annular piezoelectric ring having inner and outer cylindrical electroded surfaces concentric with the axis of the ring, electrical conductors respectively connected to the inner and outer electroded surfaces for conducting away from the hydrophone electrical signals representative of strains produced in the piezoelectric ring by sound pressure waves in the water, said ring having annular end surfaces at the two opposite ends thereof, and a pair of thin circular diaphragms respectively covering the opposite ends of the ring having circumferential portions adjacent the periphery of each diaphragm secured to said annular end surfaces, said diaphragms being each permanently formed inwardly toward the axial center of the ring defining inwardly dished zones substantially throughout the diaphragm portion lying radially inwardly of said inner cylindrical surface.

Claim 6

A marine hydrophone assembly as defined in claim 3, wherein said assembly includes diaphragm support means, said diaphragm support means including a circular resilient ring of substantially circular cross-section and having a diameter corresponding substantially to the mean diameter of the piezoelectric ring, means securing said resilient ring to said hydrophone unit against the surface portion of one of said diaphragms lying between the said inner and outer cylindrical surfaces, and means supporting said resilient ring within said seismic streamer in coaxial relation to the streamer axis.

Claim 7

A marine hydrophone assembly as defined in claim 3, including diaphragm supporting means and a second hydrophone unit like said first-mentioned hydrophone unit, said diaphragm supporting means having opposite annular end walls substantially coextensive with the annular end surfaces of said ring, and means for supporting said first-mentioned hydrophone unit and said second hydrophone unit respectively on said end walls with said hydrophone units supported in coaxial relation to a longitudinal axis of the streamer and spaced longitudinally along said axis.

Claim 8

A marine hydrophone assembly as defined in claim 5, wherein said diaphragm supporting means is an axially elongated substantially hollow supporting cylinder having perforations in the cylindrical wall thereof for communication of fluid pressure waves into the hollow portion of said cylinder and against the diaphragms of the two hydrophone units facing in confronting relation to each other and to said cylinder, and said means for supporting said hydrophone units on the annular end walls of said supporting cylinder comprising a circular ring of substantially circular cross-section and having a diameter corresponding substantially to the mean diameter of the piezoelectric ring secured to each respective annular end walls and to the adjacent confronting portion of the confronting diaphragms of the respective hydrophone units.

Claim 9

A marine hydrophone assembly as defined in claim 6, wherein the assembled supporting cylinder and pair of hydrophone units are supported within a cylindrical enclosure, the supporting cylinder having an outwardly projecting circumferential rib at the axial midregion thereof bearing outwardly against and secured to an enveloping cylindrical wall of the cylindrical enclosure, said cylindrical enclosure having perforated end caps for admitting fluid into the cylindrical enclosure and through said openings in said supporting cylinder, the seismic streamer having an outer jacket of circular cross-section and a pair of cylindrical plastic spacers supported therein in coaxial relation to the axis of the streamer spaced a selected distance along the axis thereof, and means extending between said spacers supporting said cylindrical enclosure therebetween in coaxial relation with the streamer.

Claim 10

A hydrophone assembly as defined in claim 7, wherein said means for supporting said cylindrical enclosure comprises an elongated hollow resilient tube having an inner diameter corresponding substantially to the outer diameter of said cylindrical enclosure for gripping and supporting the same substantially in the longitudinal midregion of the tube, said tube having a plurality of radially outwardly flaring finger formations at the opposite ends thereof pressed radially outwardly from the center axis of the tube along the surface of the adjacent spacer, and means restraining said tube against rotation relative to said spacers

Claim 11

A marine hydrophone assembly as defined in claim 8, wherein said last mentioned means comprises notches in the free edge portions of said finger formations, said seismic streamer having strain cables extending therealong through said spacers, and said notches being interfitted about said strain cables to prevent relative rotary movement of the tube with respect to the spacers.