United Technologies Corporation

Carrier Corporation

Other

Massachusetts Institute of Technology

Mitsubishi Jukogyo Kabushiki Kaisha

Raytheon Technologies Corporation

William P Patrick

Vishnu Mohan Sishtla

Duane C Mccormick

William M Proscia

Lee George Tetu

Masaharu Nishimura

Martin F Zabielski

Keizo Ohnishi

Christopher D Jones

Brian A Knight

Daniel J Seery

Karl Uno Ingard

Chiaki Yasuda

Shinichiro Kajii

Anthony C Zander

William Proscia

A compressor has first and second enmeshed rotors: rotating about first and second axes. The first rotor is supported by a bearing system carried by a bearing case. The bearing case has at least a first port to a discharge plenum. A first sound-absorbing material is positioned within the first port.

Compressor sound suppression

A compressor has first () and second () enmeshed rotors rotating about first () and second () axes to pump refrigerant to a discharge plenum (). The compressor includes a muffler system () comprising a sound absorbing first element () and a sound absorbing second element (). The second element at least partially surrounds the first element and defines a generally annular flow path portion () between the first element and the second element. A wall () at least partially surrounds the second element. A space () optionally containing a sound absorbing third element () surrounds the wall.

Compressor muffler

A liner assembly includes a plurality of aligned passages providing a large open area combined with openings much smaller than a length of the passages. The plurality of passages are disposed parallel with each other and include an opening transverse to incident sound waves. The passages are separated by walls and are blocked at an end distal from the openings. Sound waves incident on a face of the liner enter the passages and are dissipated by viscous losses. Sound energy is further dissipated as thermal energy to the walls of the passages. The long narrow passages provide the desired visco-thermal losses for sound energy in a broad frequency range.

Anechoic visco-thermal liner

A cooled acoustic liner useful in a fluid handling duct includes a resonator chamberwith a neck, a face sheet, and a coolant plenumresiding between the face sheet and the chamber. Coolant bypasses the resonator chamber, rather than flowing through it, resulting in better acoustic admittance than in liners in which coolant flows through the resonator chamber and neck. In one embodiment, the liner also includes a graze shield. Openingspenetrate both the face sheet and the shield to establish a relatively low face sheet porosity and a relatively high shield porosity. The shielded embodiment of the invention helps prevent a loss of acoustic admittance due to fluid grazing past the liner. Another embodiment that is not necessarily cooled, includes the resonator chamber, low porosity face sheet and high porosity shield, but no coolant plenum for bypassing coolant around the resonator chamber. An associated method of retrofitting an acoustic treatment into a fluid handling module includes installing openings in the module and mounting a resonator boxon the module so that the inlets to the resonator necks register with the installed openings.

High admittance acoustic liner

An active acoustic wall has sound-pressure detectors provided within respective cells so that a detected signal acts to oscillate an oscillation plate in the cell. A porous material on a surface is thereby provided with a high sound absorption coefficient over a wide frequency range. A space between a porous material or a perforated plate 1 on the surface and a back material fixed on a back side is divided into a plurality of sections so as to form cells 10 containing an air layer or a porous sound-absorbing material. Oscillation plates 6 are arranged within respective cells 10 so as to be driven for oscillation by oscillation-plate driving units 5. Sound-pressure detectors 7 are provided close to the porous material 1 in the cell 10 so that a detected signal is inputted to a signal-processing unit 8. The signal processing unit 8 outputs a signal to the driving unit 5 for oscillating the oscillation plate 6 such that an output of the sound-pressure detector is minimized. The sound pressure on the surface of the porous material 1 is minimized at all frequencies. The velocity of particles on the surface becomes large so that the particles are turned into thermal energy, thereby providing a high sound-absorption coefficient.

Active acoustic wall

The sound attenuating device of the present invention is a bulk layer connected to a support member which forms a plurality of Helmholtz resonators. This invention is particularly useful in a vehicle where the bulk layer attenuates high frequency noise, i.e. above about 1000 Hz, while the resonators can be tuned across the device to absorb at different lower frequencies in different areas of the device.

Tunable recyclable headliner

An acoustic sensing means such as a microphone or a thin-film sensor is located in a flowing medium. To prevent the sensing of flow generated noise, the sensing means is separated from the flowing medium by at least three stages of shielding. In a preferred embodiment, the sensing means is located within a foam shield which is located in a frame covered by a fabric shield and which is, in turn, located in a second frame covered by a second fabric shield. A spandex fabric is suitable for use in the present invention.

Multistage turbulence shield for microphones

An active noise control system includes sensors 16,26 which detects noise 114 and provides electronic signals to an active noise control (ANC) controller 20. The controller provides electronic anti-noise signals to a speaker 24 which is connected to, and provides acoustic anti-noise into, a plurality of active resonators 120-124. The resonators 120-124 are disposed successively along the propagation direction of the noise 114 and provide time-delayed anti-noise acoustic output signals each of which attenuates a portion of the noise 114. The phasing of the anti-noise signals from the resonators 120-124 may be accomplished by acoustic and/or electronic time delays.

Active noise control using phased-array active resonators

A flashback resistant burner for lean fuel/air mixtures includes apparatus for mixing a primary fuel and combustion air to form a noncombustible fuel/air mixture. Means are provided for accelerating the noncombustible fuel/air mixture to a velocity higher than the flame speed of a combustible mixture of the primary fuel and air. Means are further provided for mixing a secondary fuel with the accelerated noncombustible fuel/air mixture to form a combustible fuel/air mixture that has an equivalence ratio less than 1. Means are then provided for burning the combustible fuel/air mixture.

Flashback resistant burner

A lined duct is divided into two parallel branches by means of a rigid partition. The phase speed of the fundamental mode in each branch depends on the liner configuration and can differ markedly from the free-space phase speed. When the liners in the two branches are not the same, the corresponding phase speeds will be different and a relative phase lag between the waves in the two branches results. This, in turn, leads to interference between these wave components (and their reflections) both at the exit and entrance of the parallel branch pair. This interference can be exploited for the purpose of obtaining a low-frequency attenuation which is substantially larger than the attenuation of the unpartitioned duct.

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Glastonbury, CT, United States of America

William P Patrick