USA As Represented by Secretary of the Navy

Other

Thomas J Hofler

Steven L Garrett

David A Brown

Michael R Brininstool

Jeffrey T Newmaster

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.

Heat driven acoustic power source coupled to an electric generator

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.

High-efficiency heat-driven acoustic cooling engine with no moving parts

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.

Fiber optic accelerometer with centrally supported flexural disk

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. Several of the disks may be coaxially mounted to provide increased sensitivity.

Fiber optic flexural disk accelerometer

A sensor provides remote angular orientation sensing. A rotational signal transmitted to a rotatable input shaft mounted in an encoder body causes the shaft to rotate. Light signals are transmitted through a digital code wheel mounted to the shaft. As the code wheel and shaft rotate, the light signals passing through the code wheel are superimposed with light pulses corresponding to incremental and directional changes of angular position of the code wheel with respect to the encoder body. The light signals are propagated through an optical fiber to a remote combination digital and analog circuit which converts them into a digital representation of the angular position of the code wheel.

Fiber optic angular orientation sensor digital serial encoding

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.

Flexural disk fiber optic hydrophone

A method for remotely detecting the angular position of a rotatable code wheel is provided by generating two sine wave modulated light beams which are orthogonally polarized with respect to each other. The beams are combined and then directed through a polarization filter mounted on the code wheel. The combined beam incurs a phase shift with respect to a reference signal which depends upon the position of the code wheel. The combined polarized beam provides angular position resolution between zero and ninety degrees, but lacks quadrant resolution. Two other light beams are directed to a two channel digital mask pattern imprinted on the code wheel. The mask pattern encodes these latter beams with 'on' or 'off' pulses to provide quadrant resolution. The beams are converted to digital electric signals which are received by a programmable read oly memory (PROM). The PROM provides an output corresponding to the angular position of the code wheel to a display.

Growing community of inventors

Monterey, CA, United States of America

Thomas J Hofler