Abstract: A fiber optic bundle towed line array having a central strength member and plurality of longitudinal optical fibers spaced around the bundle near the array outer circumference. Each fiber has at least one in-line intensity modulated optical fiber hydrophone inserted at different preselected locations therealong. Patting material is molded around and embeds the optical fibers and the strength member so as to form a small diameter integral array unit.

Abstract: A small diameter towed acoustic line array comprising a plurality of miniature fiber optic lever hydrophones spaced at preselected locations along the array and held in place by fiber holders. The array hydrophones are enclosed within a tubular outer sheath which is filled with an acoustically transparent fluid. The hydrophones respond to either the pressure mode or the pressure gradient mode, each hydrophone further comprising at least one receiving and one transmitting optic fiber of the same diameter, a covering sheath, a clear elastomer and a small reflector. The information received is transmitted to and processed by a beamformer external to the array.

Abstract: An underwater transducer comprises a piezoceramic transduction layer and a etal substrate with a thin film of viscous fluid between them. The viscous film allows the transduction layer and substrate to expand and contract relative to each other when the laminate bends under increasing hydrostatic pressure as the transducer descends in a body of water. At sonic frequencies, however, the viscous film provides effectively a rigid bond between the transduction layer and the substrate so that they vibrate in unison. The invention reduces hydrostatic compressive loading on the transduction layer and thereby improves performance in deep water applications. A ring on the substrate surrounds and is engaged by the edge of the transduction layer as hydrostatic pressure increases in order to apply enough compressive stress to the transduction layer to prevent peaks in dynamic loading from exceeding the tensile limits of the transduction layer.

Abstract: A control valve for use in geophysical surveying is disclosed. The valve contains a housing having a through bore intersecting with a fluid path. The fluid passes from an input port to an output port. A seat having recess thereof is placed in the fluid path in the through bore. A poppet assembly is attached to the through bore at the end opposite to the seat. The poppet assembly contains a poppet one end of which is adapted to match the recess and moveable in opposite directions by a motor. A decoder is coupled to the motor for causing the motor to turn in the desired direction. When the motor is turned in one direction, the poppet moves toward the seat and completely closes off the fluid path between the input and output ports. To open the valve, the motor is moved in the opposite directions to move the poppet away from the seat until the fluid path is open.

Abstract: An condenser microphone element including a silicon core, a layer of silicon dioxide thereon, and a layer of tantalum pentoxide thereon.

Abstract: The invention relates to an electrical discharge circuit between two electrodes. The circuit includes switch means connected in parallel between the electrodes and constituting a switch that is closed for low frequency currents and that is open for high frequency currents. The discharge circuit may be used to detect and correct the position of an electrode at will, in manner that is simple, reliable, cheap, and suitable for being automated.

Abstract: The method of implanting a geophone in the earth including the steps of drilling a borehole in the earth, pumping grout into the borehole, pumping a geophone down the interior of a cylindrical pipe positioned in the borehole, the end of the pipe being adjacent the desired point of implantation of the geophone, and pumping additional grout into the borehole to completely surround the geophone and allow the grout to solidify. In one embodiment, a tubular drill pipe having a severable drill bit at the lower end is first used to drill a borehole, after which the drill bit is hydraulically severed from the tubular drill pipe and the grout and the geophone are pumped down into the hole through the interior of the drill pipe.

Abstract: In the underwater sound source disclosed herein, rigid diaphragms are provided at opposed ends of a hollow shell, the periphery of each of the diaphragms being sealed to the shell. Respective spring means operating between the shell and each of the diaphragms allows axial displacement of the diaphragm in response to external pressure. A lightweight magnetic armature structure is connected to each of the diaphragms and opposed electromagnetic core structures provide magnetic circuits which link each of the armature structures across respective gaps. Further spring means are provided for centering each of the armature structures between the respective magnetic core structures. By appropriately energizing windings on the magnetic core structures, the armatures together with their respective diaphragms are caused to oscillate.

Abstract: A housing with a fluid flow bore is provided with an integral diaphragm forming a cavity within the housing to position the diaphragm adjacent the bore, for receiving sensors thereon to receive intelligence from the housing indicative of any one or all of a plurality of physical functions related to strain in the housing such as by way of example, pressure of fluid in the bore of the housing, axial load, torsion, shear or bending and communicate or transmit the intelligence of such functions to a predetermined location. Where desired, the cavity may be precharged with an inert gas to inhibit damage to the sensors and to serve as a reference pressure. The cavity and transducer therein are isolated from ambient conditions externally of the housing. A flow conduit may be connected at each end of the housing to conduct fluid to the housing bore. Where necessary the intelligence relating to the function or functions may be compensated for temperature or second order effects related to any or all of the functions.

Abstract: A reloading press that is convertible between different capabilities. The press utilizes a basic structure to which interchangeable conversion sets are individually mounted to provide a reloading press with a capability. To change the capability of the press, one conversion set is interchanged with another. The interchange of the conversion sets permits a user to convert the reloading capability of the press such as from a single station to an indexable multiple station. The conversion sets include top plates for holding a tool or tools, and a shell holder mountable to the ram. Components may be added or interchanged between conversion sets to convert the capability of the press further such as converting from one caliber to another or converting a multiple station press from manual to automatic indexing. The basic structure utilizes a rugged support extending from the base for supporting the interchangeable top plates.

Abstract: A primer pocket cleaner for cartridge cases has a bundle of bristles mounted in a base with a retractable spring surrounding the bristles. The base is mounted in a motor to rotate the bundle of bristles. The spring keeps the bundle of bristles together while allowing them to vibrate as a cartridge case primer pocket is pressed against the end of the rotating bundle of bristles not mounted into the base.

Abstract: A signalling device with a long audible range is described, which is intended for underwater communication between divers. The device consists of a compact and lightweight horn and a rubber bulb. The horn, which works independently from a diver's supply of breathing air, is filled with water and operated by manually squeezing the rubber bulb.

Abstract: A method for using mode converted P- or S- wave data to delineate the surface of an anomalous geologic structure such as a salt dome is disclosed. Seismic wavefields are propagated from near the surface, through the earth, and through the anomalous geologic unit, so that a wavefield encounters the geologic unit at a non-normal incidence angle to generate a converted S- wave. Incidence angles of the direct arrival and converted waves are then determined. The intersection point of each converted S- wave raypath with each direct arrival raypath is determined, to provide a length of the raypaths. Travel times along the raypaths are determined, and a point on the interface of the anomalous geologic unit with the surrounding earth is determined by comparing raypath travel time differences with the recorded arrival time differences.

Abstract: A sonde for acquiring seismic signals in a borehole, the sonde comprising: a detector module (30) enclosing at least one seismic sensor (G); an elongate body (21) having a lateral cavity (22) suitable for receiving the detector module (30); a resislient suspension (40, 50) connecting said module to said body; and an anchor member (12, 13) disposed on the opposite side of said body to the side in which said cavity is disposed. The sonde is characterized by the fact that the resilient suspension exerts a force on said module suitable for displacing it out from the cavity and for pressing it against the wall of the borehole so as to couple it to said wall, together with means (41, 43, 51, 53, 60) which are provided to retract the module into said cavity against the force exerted by the resilient suspension.

Abstract: A borehole cable includes a plurality of geophone-containing modules spaced apart along the cable by a plurality of conduit sections and designed for acoustic, thermal and pressure imaging of the subsurface. Each cable conduit section comprises an inner core of flexible tubing and an outer wall of interlock completely surrounding the core. The inner corrugated core is designed to compress under the external pressure applied by the formation in which it is deployed. The percent of core compression is controlled by adjusting the composition and structure of the inner core and the outer interlock wall. Compression of the inner core beyond a predetermined limit causes the interlock to form a rigid outer wall preventing further compression. The pressure at which the inner core begins to compress and the percent of compression at which the outer wall locks is determined by their material composition, wall thickness and pre-compression during manufacturing.

Abstract: The present invention relates to a communications protocol for a digital telemetry system which enables more efficient digital data transmission between a plurality of digital communications nodes. The protocol is implemented using uplink and downlink packets and superpackets. Each node forms an uplink packet which contains node data and protocols. Those packets are packaged into uplink superpackets and transmitted to a control node. Downlink superpackets containing information signifying which of the uplink superpackets were received correctly are formed and transmitted to the individual nodes. In response, any uplink superpacket received incorrectly is retransmitted. Additionally, the communications protocol also time stamps messages received from the nodes to provide for digital communications time correlation.

Abstract: A borehole seismic tool including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric meter in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

Abstract: A human-portable geophysical energy source is disclosed having an earth-coupling element, a means for providing seismic energy operably connected to that earth-coupling element, a lower container and an upper container connected to the means for providing seismic energy, a framework that minimizes vibrations of the liquid by keeping the upper and lower containers inflexible when they are completely filled with liquid, and a hydraulic pump for filling and removing liquid from the containers. The lower container is located spatially between the earth-coupling element and the means for providing seismic energy. The upper container is located spatially above the means for providing seismic energy. The liquid provides mass to impart energy through the earth-coupling element and to maintain coupling with the earth.

Abstract: Amplification or generation of very low (and variable) frequency, low voltage, high current bipolar signals useful in electrical borehole telemetry systems is achieved using a duty cycle control device for causing the alternate direct application of a positive voltage and a negative voltage to an integrator. A commutated clamp is connected to the input of the integrator for switchably connecting the integrator directly into a current loop with the load, connected to the output of the integrator, when neither voltage is being applied to the input of the integrator.

Abstract: Structure-borne intensities in a vibrating plate radiator having at least one source of vibration are measured without contacting the radiator by producing a pressure hologram of the pressure radiated from the surface of the radiator, determining the normal velocity of the radiator surface from the pressure hologram, and determining at least one component of the structure-borne intensity from the normal velocity.