Self-righting geophone

Claim 2

A seismic detector comprising: a tubular element constructed of piezoelectric material, end pieces for hermetically enclosing the interior of said tubular element, said end pieces being constructed of electrically nonconductive material, metal plate electrode means disposed on the interior one of said end pieces, said plate electrode mEans being sized to be equidistantly spaced from the interior wall of said tubular element, electrode means attached to the outer surface of said tubular element, mercury in said tubular member in an amount less than one-half of the volume of said tubular member for coupling said piezoelectric element to said metal plate member, and output conductors coupled to said electrode means.

Claim 3

The detector of claim 1 and further including means in the interior of said tubular member for inhibiting splash of said mercury.

Claim 4

The detector of claim 2 wherein said splash inhibiting means is an open cell foam which fills the interior of said tubular member.

Claim 5

The detector of claim 2 wherein said mercury has a dissolved metallic element therein for loweringthe freezing point of the mercury solution.

Claim 6

A seismic detector comprising: first and second axially algined tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surface of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.

Claim 7

A seismic detector comprising: first and second axially algined tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surface of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.

Claim 8

The detector of claim 5 and further including means defining an opening to said tubular members, and a self-sealing substance plugging said opening.

Claim 9

The detector of claim 5 wherein said plate members are made of stainless steel material and are attached to said end walls by bolts made of stainless steel material.

Claim 10

The detector of claim 5, wherein the amount of mercury in said tubular members is contained within a segment of a tubular member defined by a sector angle of 90*.

Claim 11

The detector of claim 5 wherein said tubular elements are respectively electrically polarized in opposing radial directions.

Claim 12

A sub-assembly for a seismic detector comprising a cylindrical, electrically nonconductive housing having a central bore, a seismic detector snugly receivein said central bore, said seismic detector being comprised of first and second axially algined tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surfaces of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.

Claim 13

A sub-assembly for a seismic detector comprising a cylindrical, electrically nonconductive housing having a central bore, a seismic detector snugly receivein said central bore, said seismic detector being comprised of first and second axially algined tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surfaces of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.

Claim 14

A seismic cable for surface exploration comprising an elongated supporting cable means having strength carrying members and seismic bulkhead supports disposed along its length, at least some of said bulkheads having a cylindrical electrically nonconductive housing having a central bore and being disposed in intimate contact relationship with respect to the cable portion around said bulkhead, seismic detectors snugly-received in said central bores, said seismic detectors being compriSed of first and second axially aligned tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surfaces of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.

Claim 15

A seismic cable for surface exploration comprising an elongated supporting cable means having strength carrying members and seismic bulkhead supports disposed along its length, at least some of said bulkheads having a cylindrical electrically nonconductive housing having a central bore and being disposed in intimate contact relationship with respect to the cable portion around said bulkhead, seismic detectors snugly-received in said central bores, said seismic detectors being compriSed of first and second axially aligned tubular elements respectively constructed of piezoelectric material and having an outer metallic coating, a central separating wall and end walls for hermetically sealing off the interior of said tubular elements and defining first and second enclosed chambers, said walls being constructed of electrically nonconductive material, circular shaped plate members disposed on the interior surfaces of said end walls and having a peripheral spacing with respect to said tubular elements, mercury in said tubular members in an amount less than one-half the volume of a tubular member for coupling said piezoelectric element to said metal plate member, means in the interior of said tubular elements for inhibiting splash of said mercury, means coupling said outer coatings to one another, and output conductor means coupled to said plate members.