Abstract: A continuous wave driven ultrasonic transducer for determining doppler frequency shift in reflected ultrasonic pressure waves in which the transmitter and receiver sections are constructed of a composite core having a plurality of segments of piezoelectric material separated by acoustic suppression material. Also disclosed is a method of reducing acoustic and mechanical cross coupling between piezoelectric transmitter and receiver sections of an ultrasonic transducer by arranging segments of piezoelectric material in a lateral array, and separating the piezoelectric segments with ultrasonic acoustic suppression material to produce a composite transducer core of reduced acoustic and mechanical cross coupling.

Abstract: A transducer assembly providing a conversion between the electrical and sonic energy, the transducer assembly being adapted for operating submerged at great depths in ocean waters. The transducer assembly is formed by a front and back plate which are affixed in one embodiment to the ends of a first mechanically distributed impedance member, a second mechanically distributed impedance member located between the front and the back plate and a transducer of electroacoustical material mechanically coupling the first and second members for imparting sonic vibrations to these members. In a preferred embodiment, the transducer is bonded at one end thereof to the back plate and at the other end thereof to the second member. External hydrostatic pressure present at the front and back plates does not compress the electroacoustical material.

Abstract: A solid-state tunable transducer has been developed by incorporating an elastically nonlinear material, silicone rubber, into an electroacoustic transducer made from piezoelectric ceramics. The resonant frequency and mechanical Q of the transducer are tuned mechanically by applying a uniaxial compressive stress to the composite. The resonant frequency is tuned electrically by placing a piezoelectric actuator into the composite and varying the magnitude of the d.c. bias.

Abstract: A support member preferably made of a metal such as cold rolled steel is disposed in a looped configuration and is provided with a gap. A transducer member preferably made of a piezoelectric material such as a ceramic is disposed within the support member. The transducer member is provided with a gap at a position corresponding to the gap in the support member. A closure member made from a suitable springlike material such as an alloy steel is attached to the opposite ends of the support member at the position of the gap as by welding. The closure member extends in a U-shaped configuration into the looped configuration (in section) defined by the support member and the ceramic member. The axial length of the closure member defines the bandwidth of the frequency vibrations generated by the transducer member.

Abstract: The sonar transducer includes a metal core about which is situated a cylindrical piezoelectric ceramic ring element with paper interposed therebetween. In order to improve resistance to fracture resulting from mechanical shock, in one embodiment, the core is reduced in diameter, such that a potting compound can be situated between the paper and the ring. In a second embodiment, the ring element is divided into two individual, axially aligned cylindrical ring subelements with a gasket interposed therebetween.

Abstract: A flextensional sonar transducer comprising a first cavity defined by an elliptical shell and end plates covering the two ends of the shell, vibration drive means inside the cavity and coupled between portions of the shell wall at opposite ends of the major axis of the shell, a further cavity connected to the first cavity and an opening between the two cavities for coupling the two cavities for the further cavity to affect the resonant frequency of the first.

Abstract: Various configurations of cylindrically shaped transducers are used as borehole seismic wave sources. The basic class of transducers of this invention has an outer shell that is generally cylindrical, and may be comprised sections. The shell or the sections may be pre-stressed or preformed to encourage certain bending motions. Depending on the configuration of the transducer, it approximates a monopole, dipole, or quadrupole radiator. Various actuating means, including magnetostrictive forces and piezoelectric forces, are used to drive the motions of the transducer. These transducers are especially useful for generating compressional, shear, or other elastic waves in solids. For example, in geophysical applications, the transducers are placed in boreholes for either hole-to-hole or single hole measurements.

Abstract: A transducer assembly includes a hollow support member disposed in a looped configuration and having an axial opening. A hollow transducer supported within the support member may be made from a piezoelectric material and may be provided with an axial opening corresponding to position to the axial opening in the support member. In one embodiment, the outer surface of the support member may be thinned at spaced positions as by sockets or spaced axial grooves extending partially through the support member. The support member may be thinned at strategic positions to control the vibrational frequency and the frequency bandwidth of the transducer assembly. The thinned portions of the support member may receive a compliant material such as urethane to smoothen the outer surface of the support member. In another embodiment, the hollow interior of the transducer assembly may be filled with a compliant material, such as urethane, which may be provided with air chambers.

Abstract: A transducer array designed for towing at an extended distance behind a sace vessel includes electroacoustical transducer elements connected in opposition to the active elements of the array. A surrounding acoustic isolation structure effectively isolates the dummy transducer elements from the ambient noise field while permitting cancellations of self-induced noise.

Abstract: A signal sensor automatically compensates for the variations of the static pressure of the medium in which it is placed. The signal sensor comprises one or two assemblies each formed of a piezoelectric sensitive element applied against one face of a flexible plate. The other face of the plate is shielded from the variations of the dynamic pressure to be measured by a material absorbing the vibrations but fairly flexible so as to transmit any variation of the ambient static pressure. This material which may be a porous foam or a fibrous substance impregnated with liquid, fills a tubular apertured sleeve.

Abstract: An inner decoupler for a sonar array including a linear array of hydrophones and consisting of an alternating multi-layer configuration of acoustic compliance elements in the form of acoustic baffles and acoustic non-compliance elements in the form of water or other acoustic mass-like element located between the hydrophones and the outer surface of a ship's hull. This arrangement embodies an acoustic low pass filter between the hydrophones and the hull and operates to enhance incoming signals incident to the sonar array while attenuating signals such as structure borne noise generated from the opposite or hull side of the array.

Abstract: An ultrasonic sensor for fluid levels comprises a carrier having spaed-apart legs with registering openings adapted to receive a piezoelectric transmitter and a piezoelectric receiver in the openings. The piezoelectric members are separated by the spaced legs of a ground plane engaging plates of the piezoelectric members. Resilient members in the form of coiled conductors are entrained between a snap-on cover and the transducers so as to resiliently engage the piezoelectric members against the ground plane. The conductors are coupled by crimp connectors to the leads of a cable carried by an elongated channel portion of the carrier. The crimp conenctors are caried in recessed portions of the carrier, and the carrier is over-molded to encase the connectors and the cable. The cable is in turn coupled to an electronic control module positioned remotely from the fluid sump and connected to a warning device.

Abstract: An automatic ultrasonic system for controlling the filling of different sizes of beverage containers which may or may not contain various quantities of ice. The system includes a transducer assembly and a control module, both preferably connected to a beverage dispenser valve assembly. The transducer assembly includes at least two piezo-electric crystals for separately transmitting and receiving ultrasonic wave energy from the grate, the cup lip, the top of any ice in the cup, and the rising liquid level, and for generating signals corresponding to the travel time of the ultrasonic energy. The control module includes a microcomputer and associated circuitry. The system can include two separate transmitter and receiver crystals, or in a preferred embodiment two transmitter-receiver pairs of crystals.

Abstract: An improved acoustic baffle for use with underwater hydrophone or acoustic transducer equipment on submarines and the like for attenuating acoustic energy of a noise character emanating from the submarine carrying the hydrophone equipment thereby rendering the hydrophone immune to undesired ambient noise conditions, incorporates a laminated assembly of compliant or spring like elements. One embodiment is characterized by a ribbed member for effecting a spacing of a plurality of rubber tubing type sound absorbing elements. An alternative embodiment incorporates a plurality of metallic springs for controlled compliancy of the baffle. The assembled elements are attached to a steel plate and before being placed in operation, a hydrophone or acoustic transducer is mounted on the opposite side of the steel plate.

Abstract: An automatic, ultrasonic system for controlling the filling of different sizes of beverage container which may or may not contain various quantities of ice. The system includes a housing, a front and a rear pair of separate transmitter and receiver crystals mounted in the housing with a lens on the lower surface of each crystal. Each crystal is located within a separate non-ferrous metal tube. Polyurethane foam fills the space within the housing and the tubes.

Abstract: An accelerometer-based direction finding and ranging transducer such as a hydrophone uses piezoelectric ceramic as the active material. Orthogonally arranged accelerometers share an inertial mass and resonance control system and the accelerometers together with a pressure hydrophone and electronics are all housed within one pressure vessel.

Abstract: An ultrasound liquid level detector system for automatically controlling the dispensing of a post-mix beverage, including microprocessor-controlled circuitry for monitoring and implementing the automatic dispensing process. The microprocessor is interfaced with an ultrasonic transducer which transmits ultrasonic wave energy towards the container to be filled and receives reflected ultrasonic wave energy, the characteristics of which are analyzed within the microprocessor to implement control functions of the automatic dispensing process. Dispensing automatically begins as a container is inserted under the ultrasonic transducer into a proper position beneath a post-mix beverage dispenser nozzle. The transducer continuously measures the distance between the top or lip of the container and a liquid/foam interface of a carbonated beverage being dispensed into the container. Dispensing stops when the transducer senses a predetermined level of carbonated beverage within the container.

Abstract: A sonar transducer assembly for a fishing boat provides electrical signals corresponding to an image of the area surrounding the boat on both sides thereof based on sound echoes received by the transducer assembly. The transducer assembly comprises a transducer housing mounted on the transom of the boat so that the bottom surface thereof is at substantially the level as the hull of the boat in the normal position of the transducer housing, and such that the transducer housing can move rearwardly and upwardly in response to hitting an object in the water. The housing is generally bullet-shaped and houses a plurality of individual transducers directed in different directions away from the hull of the boat so as to provide scanning of areas of the water beneath and on both sides of the boat.

Abstract: A compliant tube baffle for use in a marine environment wherein a boxlike structure (10) is surrounded by an elastomeric cover (64) and includes a pair of beam plates (12,14) separated by suitable means such as bent plate springs (18,20) which may be engageable with elastic cushioning layers (54) adhered to side shields (52). The beam plates (12,14) may be tapered with the tapered sections (34) having curved surfaces in the form of an ellipse. Damping may be provided by piezoelectric elements (58) or by constrained layers (66) of elastomeric material stressed during flexing movement of the beam plates (12,14). The beam plates (72,74) may also be separated at the edges (84) by elongated members (78,80) of solid elastomer or members (92,94) of a laminate of elastomer and rigid material.

Abstract: A distributed array hydrophone comprising an array of hydrophones each comprising a ceramic doublet assembly of hollow radially oppositely polarized members end held in a bobbin by decoupling means, the bobbins being linearly interconnected by semiflexible spacing members, the array being encapsulated in a vibration transmitting potting medium in a tube formed of a pressure-wave transmitting medium.

Abstract: A piezoelectrically-driven, resonant-pipe projector has formed therein vents to broaden the response of certain cavities resonances and to increase the response between these resonances. The projector exhibits a relatively high electroacoustical efficiency, is capable of medium to high power output over the operating band, and is not depth dependent or depth limited.

Abstract: A support for an elongated piezoelectric pressure sensor, which is general cylindrical in shape is mounted on a hollow support member that has a thickness and strength selected to meet desired conditions. The elongated piezoelectric pressure sensor is wound in a helical depression on the exterior of the support member, and the support member in turn is filled with a potting material having a bulk modulus of elasticity selected to provide a sufficient flexibility so that the elongated piezoelectric sensing element generates signals that have a desired sign characteristic and improved acoustic response.

Abstract: A piezoelectric polymer (PVDF) hydrophone array consists of multiple layers disposed symmetrically about a stiffener layer. The stiffener layer prevents flexural modes in the operating frequency band and provides a mounting structure for acceleration noise cancellation. The piezoelectric polymer layers are attached to the stiffener layer either directly or through intervening layers which provide mechanical vibration isolation of the polymer and stiffener layers.

Abstract: An automatic, ultrasonic system for controlling the filling of different sizes of beverage containers which may or may not contain various quantities of ice. The system includes a transducer assembly and a control module, both preferably connected to a beverage dispenser valve assembly. The transducer assembly includes a pair of piezo-electric crystals for separately transmitting and receiving ultrasonic wave energy from the grate, the cup lip, the top of any ice in the cup, and the rising liquid level. The control module includes a microcomputer and associated circuitry.

Abstract: An acoustic transmitter for borehole logging includes a flexure disc acoustic source affixed to one end of an open-ended pipe. A rubber boot surrounds the pipe and flexure disc source and fluidly isolates them from the surrounding borehole fluid. Oil fills the rubber boot and pipe, such that the borehole fluid pressure is transmitted through the rubber boot to the oil. The flexure disc source is electrically excited to cause the transmitter to generate acoustic energy tube waves at one of the resonances of the flexure disc source within the seismic frequency range.

Abstract: A flexible line array transducer assembly for detecting underwater acoustical signals. The assembly includes an array of spaced-apart piezoelectric elements arranged generally in a line and selected to have low cross-coupling characteristics, low sensitivity to incoherent mechanical perturbations in the directions longitudinal and lateral to the axis of the array, and high sensitivity to coherent mechanical perturbations such as acoustical signals. The elements are polarized in a direction generally transverse to the array and each include opposing surface areas which are generally parallel with the linear axis of the array. Electrodes are disposed on the opposing surface areas of the elements and are coupled to conductors which carry signals produced by the piezoelectric elements when the elements are stressed by acoustical signals. A porous, open-cell material is disposed about the piezoelectric elements as an encasement to maintain the elements in place and mechanically isolate the elements.

Abstract: A Tonpilz transducer having head and tail masses with an interposed active transducer section. The transducer unit is positioned within a housing which has a shoulder portion upon which rests a snubber member which extends to a position just behind the head mass. The transducer is supported from the head mass by means of a thin fiberglass tube which extends from the rear of the head mass and engages a flange portion of the snubber member in the vicinity of the housing shoulder. The housing has a waterproof covering as does the head member with the covering of the head member being secured to the covering by means of a removable strap such that the transducer assembly may be disassembled for repair.

Abstract: There is provided by this invention a broad band acoustic transducer comprising a piezoelectric crystal with a two layer dampening backing having very high attenuation properties. Each layer has an impedance matching the acoustical impedance of the crystal, however, the second layer has an attenuating additive that greatly increases its attenuation factor. The surface interface between the two dampening layers is tilted and roughened to induce wave scattering that prevents back reflections.

Abstract: Polymer compositions comprising a segmented urethane block polymer and an elastomer having a glass transition temperature between -40.degree. and +15.degree. C. possess a good combination of properties, including relatively high damping and modulus values. Radiation cross-linked tubing prepared from these compositions finds application in the jacketing of marine sonar detection arrays comprising hydrophones.

Abstract: A swimming pool alarm consists of a sensor suspended beneath the water surface of the pool, including an electrical resonator element and a captive element agitatable by the pool water adjacent the resonator element, and an alarm device external of the pool which responds to the amplitude of resonance of the resonator element exceeding a certain level.

Abstract: An improved material for an ultrasonic transducer assembly having improved noise suppression characteristics comprising an ultrasonic transducer having a plurality of surfaces, a housing for receiving said transducer whereby one surface of said transducer is free to transmit and receive ultrasonic waves, and a material positioned about said transducer and between said transducer and the environment or housing for attenuating ultrasonic energy, said material comprising a heavily loaded resin based on an unfilled low viscosity potting gel and a filler selected from the group consisting of heavy oxides, metal powders, and density lowering fillers. In specific embodiments lead oxide, tungsten powder, and glass microspheres have been used as the filler in a silicone or flexible epoxy.

Abstract: A high-temperature transducer for transmitting and/or receiving sonic energy having a housing with a cylindrical opening, a metallic acoustic window element closing one end of the opening, a cylindrical transducer crystal having one planar surface in engagement with the acoustic window rearward face, a cylindrical dampening member in contact with the crystal rearward face, a first and a second thrust disc received in the cylindrical opening with a thrust transmitting sphere between the discs, and a thrust producing compression screw threadably received in the cylindrical opening supplying pressure against the first of the thrust discs which pressure is applied by means of the sphere to the second thrust disc, to the dampening means and to the crystal rearward face to force the crystal into intimate engagement with the acoustic window for effective sound transmission.

Abstract: For use with an acoustic transmitter in an acoustic well logging tool, an improved transducer modification circuit is set forth in the preferred and illustrated embodiment. The circuit of this disclosure modifies the diameter resonant frequency of a piezoelectric transducer, thereby expanding the frequency range downward for the transmitter transducer by moving the diameter resonant frequency.

Abstract: A single element cantilever mounted shear wave transducer which takes advantage of the transverse vibration of a piezoceramic bimorph element mounted as a cantilever on a heavy slug. A gasket material between the slug and an inner holding tube assists in avoiding the propagation of undesirable compressional wave energy into transmission medium surrounding the transducer. Electrical isolation is achieved by wrapping the inner tube with a ground shield to which the ground wire is attached. A second layer of gasket material between the inner and an outer tube further inhibits the propagation of compressional wave energy into the transmission medium. A flexible potting compound seals the open end of the tubes including the bimorph element and serves as the active face of the transducer.

Abstract: A multimode hydrophone of small diameter and low weight providing dipole ectivity patterns over a decade range of low frequencies by utilizing a pair of orthogonal dipole signals and a nondirectional reference signal to eliminate directional ambiguity. Each multimode hydrophone is a thin wall tube divided electrically into quadrants which permits differencing or opposing halves to produce signals with dipole directivity patterns and the formation of a nondirectional reference signal by summing all four quadrants. The hydrophone tube comprises inert and piezoelectric materials, selected and combined so as to shift the resonant frequency of the tube lower while keeping the over-all tube diameter as small as possible.

Abstract: An ultrasonic sound absorbing material capable of operating at high temperatures and pressures, said material comprises a dense, rigid, permeable material such as sintered metal filled with a viscous fluid.

Abstract: A transducer made up of a plurality of piezoceramic tubes arranged in end to end relationship with elastomeric material between tubes. The tubes are poled and driven axially; however, the hoop mode of operation is utilized to obtain a fan-shaped beam extremely narrow in one direction and extremely broad in the direction perpendicular thereto. A suitable backing arrangement is provided for the transducer when mounted on a support body to prevent degradation of the beam pattern.

Abstract: Disclosed is an acoustic transducer which includes a pressure tight vessel with a window in the vessel which is transparent to acoustic wave energy. A gas is disposed within the vessel, while an electromechanical transducer is located within the vessel at an antinode for a resonant wave of the gas. A port communicates with the interior of the vessel, with a pressure control coupled to the port and to a source of the gas for controlling the pressure of the fluid within the vessel.

Abstract: An acoustic array for use at high hydrostatic pressures comprises an acouc isolation baffle positioned adjacent to the hull; an intermediate acoustic conditioning module supported over the isolation baffle; and an outer layer containing a plurality of hydrophone units. The acoustic isolation baffle comprises alternating layers of rigid and compliant materials bonded together in sandwich fashion, wherein the compliant layer is provided with a regular pattern of air cells. In adjoining compliant layers the pattern of air cells is translated relative to each other so that the load bearing walls of one compliant layer overlap the open cell regions of the adjacent compliant layer with only a rigid layer disposed therebetween. The acoustic conditioning module comprises spaced coverplates with spacer elements extending therebetween to form a plurality of chambers which contain viscoelastic damping elements bonded to the outer coverplate.

Abstract: An underwater acoustic array comprises an acoustic skirt baffle positioned djacent to a hull surface for reducing the transmission of shipboard noise; an acoustic conditioning module positioned over the acoustic skirt baffle; and an outer layer secured to the acoustic conditioning module and containing a plurality of hydrophone units.The acoustic conditioning module comprises inner and outer spaced coverplates; a plurality of spacer elements extending between the coverplates to form a plurality of closed chambers therebetween; and "tuned" viscoelastic damping elements secured to the outer coverplate.

Abstract: A sonar transducer especially adapted for use when subjected to high hydrostatic pressures and extreme mechanical and explosive shock. The sonar transducer includes a conventional casing, ruggedized to withstand high pressures and a hostile environment. The casing is closed on all sides but one. An array of piezoelectric ceramic stacks are suspended inside of the casing and sandwiched between a single front mass and individual rear masses. The single front mass is positioned closest to the open side of the casing. A flexible cover is sealed over the open side of the casing and pressurized oil is placed inside the housing. Appropriate channels are provided to enable the oil to freely flow throughout the interior of the unit, including flowing inside of and about the ceramic stacks. Electrical connections are made with the ceramic stacks to allow external voltages to electrically stress the stacks, and also to allow external sensing of the voltages generated when the stacks are mechanically stressed.

Abstract: The disclosure relates to a system for aerially transmitting an ultrasonic view of a vibration mode, small in angle of direction, in a clear state and to a transmitter and a receiver used in the system. According to the system, an ultrasonic pulse can be used for distance measurement, control and other signal means even at relatively short distance.

Abstract: For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.

Abstract: An integrating hydrophone sensing element is provided having improved sensitivity and capability of withstanding high pressures. The sensing element consists of a rigid cylinder with semicylindrical sensing surfaces rigidly connected to the cylinder at diametrically-opposite points. A membrane of piezoelectric polymer material extends diametrically across the cylinder and is attached to the cylinder at points displaced 90.degree. from the connections of the sensing surfaces. Vibration of the cylinder by acoustic signals transmitted from the sensing surfaces causes vibration of the membrane and produces an electrical output signal.