Abstract: The electricity generating engine has modest efficiency, but may be attrave in remote applications where high-reliability or low cost or low environmental noise or solar powering is important. The generator is likely to be most attractive in capacities of a few kW to below 100 W where a tiny engine would be impractical using other technologies.

Abstract: This invention describes a new geometry for a heat driven thermoacoustic me mover (i.e. acoustic motor) and its application to a thermoacoustic refrigerator and to an electricity generator. The heat driven acoustic refrigerator has no moving parts, and is thus extremely reliable, simple, and cheap to manufacture. Unlike previous heat driven acoustic cooling engines, it has good efficiency and compactness and is easy to start, avoiding destructively high temperatures upon start-up. The cooling engine is saleable over an extremely wide range of cooling capacities from integrated circuit and sensor cooling to building air-conditioning. The electricity generating engine has modest efficiency, but may be attractive in remote applications where high-reliability or low cost or low environmental noise or solar powering is important. The generator is likely to be most attractive in capacities of a few kW to below 100 W where a tiny engine would be impractical using other technologies.

Abstract: An accelerometer or seismometer has an elastic disk bearing a mass distributed peripherally around the disk. The disk is supported for flexure and for isolation from mounting strain by a stob centrally through the disk. The accelerometer or seismometer has a pair of flat spirals of optical fiber, each spiral being fixedly attached to a corresponding disk side so that disk flexure lengthens a spiral on one disk side and shortens a spiral on an oppositely facing disk side and so that temperature differences between the spirals are minimized. The pair of spirals are connected as legs of a fiber optic interferometer so that the interferometer provides an output corresponding to the flexure. Several of the disks and asociated pairs of spirals may be coaxially mounted to provide increased sensitivity.

Abstract: An accelerometer or seismometer has a pair of flat spirals of optical fiber and has one or more elastic disks bearing a mass and supported for flexure. Each spiral is fixedly attached to a corresponding disk side so that disk flexure lengthens a spiral on one disk side and shortens a spiral on an oppositely facing disk side, the spirals being connected as legs of a fiber optic interferometer so that the interferometer provides an output corresponding to the flexure. A pair of the disks may be mounted oppositely of a sealed body with a pair of the spirals arranged to minimize the effect of pressure changes on the sensor, and a pair of the spirals may be mounted oppositely of a thermally conducting disk to minimize temperature differences between the spirals. The mass may be centrally mounted on a disk with the disk peripherally supported, or the mass may be distributed around the disk periphery with the disk centrally supported for isolation from mounting strain.

Abstract: A hydrophone or other acoustic vibration sensing apparatus having a disk circumferentially supported for flexure induced by acoustic vibrations and wound on each side with a flat spiral of optical fiber fixedly attached to the disk side so that flexure of the disk due to the vibrations lengthens the spiral on one side and shortens the spiral on the other side. The spirals are connected as two legs of a fiber optic interferometer to provide an output corresponding to the vibrations while canceling errors due to pressure and temperature effects common to the legs. A pair of the disks and associated optical fiber spirals may be mounted on opposite ends of a body with the outer spirals connected as one interferometer leg and the inner spirals as another leg to cancel differences in the lengths of the legs due to acceleration induced flexure of the disks and to provide double the sensitivity to pressure differential of a single disk.

Abstract: A heat-driven acoustic cooling engine having no moving parts receives heat from a heat source. The acoustic cooling engine comprises an elongated resonant pressure vessel having first and second ends. A compressible fluid having a substantial thermal expansion coefficient and capable of supporting an acoustic standing wave is contained in the resonant pressure vessel. The heat source supplies heat to the first end of the vessel. A first heat exchanger in the vessel is spaced-apart from the first end and receives heat from the first end. A first thermodynamic element is adjacent to the first heat exchanger and converts some of the heat transmitted by the first heat exchanger into acoustic power. A second thermodynamic element has a first end located spaced-apart from the first thermodynamic element and a second end farther away from the first thermodynamic element than is its first end. The first end of the second thermodynamic element heats while its second end cools as a consequence of the acoustic power.

Abstract: An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element.