# US 10,119,525 B1 · Alpha-stream convertor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,525 B1 - Document ID: US10119525B1 - Status: Granted - Kind: B1 - Application number: 14/719,885 - Filed: 2015-05-22 - Granted: 2018-11-06 - Earliest claimed: 2012-06-27 - Assignees: United States of America as Represented by the Administrator of - Applicants: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Inventors: Rodger W. Dyson; Geoffrey A. Bruder - Web page: https://patentgrep.com/patent/US10119525B1 ## CPC - F02G 1/04: of closed-cycle type - F03G 7/002: {using the energy of vibration of fluid columns} - F03G 7/027: {Control or monitoring} - F02G 2243/54: thermo-acoustic - F02G: HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS (steam engine plants, special vapour plants, plants operating on either hot gas or combustion-product gases together with other fluid F01K; gas-turbine plants F02C; jet-propulsion plants F02K); USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR - F03G: SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR (arrangements in connection with power supply in vehicles from force of nature B60K16/00; electric propulsion with power supply in vehicles from force of nature B60L8/00) ## Abstract A thermo-acoustic engine and/or cooler is provided and includes an elongated tubular body, multiple regenerators disposed within the body, multiple heat exchangers disposed within the body, where at least one heat exchanger is disposed adjacent to each of the multiple regenerators, multiple transducers axially disposed at each end of the body, and an acoustic wave source generating acoustic waves. At least one of the acoustic waves is amplified by one of the regenerators and at least another acoustic wave is amplified by a second one of regenerators. ## Claims ### Claim 1 A method of operating a thermo-acoustic engine comprising: establishing a first temperature gradient in a first regenerator and a second temperature gradient in a second regenerator; creating a first acoustic wave in the first regenerator that propagates along a propagation path; creating a second acoustic wave in the second regenerator that propagates along the propagation path, wherein there are no electrical acoustical signal generators disposed along the propagation path between the first and second regenerators; superimposing the first acoustic wave and the second acoustic wave to form a combined acoustic wave having an amplitude higher than the first and second acoustic waves; converting the combined acoustic wave to an electrical signal; and outputting a portion of the electrical signal to drive a first transducer. ### Claim 2 (depends on 1) The method of claim 1 further comprising outputting another portion of the electrical signal to a device external to the thermo-acoustic engine. ### Claim 3 (depends on 2) The method of claim 2 further comprising tuning the portion of the electrical signal to a resonant frequency. ### Claim 4 (depends on 1) The method of claim 1, wherein the first temperature gradient and the second temperature gradient are established by a plurality of heat exchangers. ### Claim 5 (depends on 4) The method of claim 4, wherein the plurality of heat exchangers includes a first heat exchanger disposed adjacent to a side of the first regenerator, a second heat exchanger disposed adjacent to an opposite side of the first regenerator and adjacent to a side of the second regenerator, and a third heat exchanger disposed adjacent to an opposite side of the second regenerator, and wherein the first heat exchanger heats or cools the side of the first regenerator to a temperature greater than a temperature that the second heat exchanger heats or cools the opposite side of the first regenerator and the second heat exchanger heats or cools the side of the second regenerator to a temperature greater than a temperature that the third heat exchanger heats or cools the opposite side of the second regenerator. ### Claim 6 (depends on 4) The method of claim 4, wherein the plurality of heat exchangers includes a first heat exchanger disposed adjacent to a side of the first regenerator, a second heat exchanger disposed adjacent to an opposite side of the first regenerator and adjacent to a side of the second regenerator, and a third heat exchanger disposed adjacent to an opposite side of the second regenerator, and wherein the first heat exchanger and the third heat exchanger are hot heat exchangers and the second heat exchanger is a cold heat exchanger. ### Claim 7 (depends on 1) The method of claim 1, further comprising, prior to outputting the portion of the electrical signal to drive the first transducer, applying a phase delay to the portion of the electrical signal. ### Claim 8 (depends on 7) The method of claim 7, further comprising, prior to outputting the portion of the electrical signal to drive the first transducer, combining the portion of the electrical signal with the phase delay with an incoming electrical signal to generate a combined electrical signal. ### Claim 9 (depends on 8) The method of claim 8, further comprising feeding the combined electrical signal to the first transducer. ### Claim 10 (depends on 9) The method of claim 9, wherein the conversion of the combined acoustic wave to the electrical signal is performed via a second transducer. ### Claim 11 (depends on 1) The method of claim 1, wherein the first and second regenerators are each disposed within a body having a central axis, wherein the first and second regenerators are disposed on the central axis at different points along the central axis such that the first and second acoustic waves are at different axial locations within the body. ### Claim 12 (depends on 11) The method of claim 11, wherein the combined acoustic wave is a standing wave within the body. ### Claim 13 (depends on 11) The method of claim 11, wherein the first transducer is disposed proximate to an end of the body. ### Claim 14 (depends on 13) The method of claim 13, wherein, in the first temperature gradient, a temperature in the first generator increases with proximity to the end of body, wherein, in the second temperature gradient, a temperature in the second generator increases with proximity to the end of the body. ### Claim 15 (depends on 13) The method of claim 13, wherein, in the first temperature gradient, a temperature in the first generator decreases with proximity to the end of body, wherein, in the second temperature gradient, a temperature in the second generator decreases with proximity to the end of the body. ### Claim 16 (depends on 13) The method of claim 13, wherein, in the first temperature gradient, a temperature in the first generator increases with proximity to the end of body, wherein, in the second temperature gradient, a temperature in the second generator decreases with proximity to the end of the body. ### Claim 17 (depends on 13) The method of claim 13, wherein, in the first temperature gradient, a temperature in the first generator decreases with proximity to the end of body, wherein, in the second temperature gradient, a temperature in the second generator increases with proximity to the end of the body. ### Claim 18 (depends on 5) The method of claim 5, wherein the first regenerator directly contacts the first and second heat exchangers. ### Claim 19 (depends on 18) The method of claim 18, wherein the second regenerator directly contacts the second and third heat exchangers such that the first heat exchanger, the first regenerator, the second heat exchanger, the second regenerator, and the third heat exchanger form a continuous body.