Silencer attenuating a noise from a noise source to be ventilated and a method for active control of its noise attenuation system

• US 5,253,486 A
• Filed: 04/26/1991
• Issued: 10/19/1993
• Est. Priority Date: 05/01/1990
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sekiguchi, Yasuyuki, Nakanishi, Keiji, Sugahara, Masanori
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/692,359
• Time in Patent Office: 907 Days
• Field of Search: 62/296, 62/115, 181/202, 181/200, 181/206, 381/71, 381/73.1, 381/94, 417/14, 417/312
• US Class Current: 62/296
• CPC Class Codes: F25B 2500/12 Sound
• CPC Class Codes: F25D 2201/30 with respect to sound
• CPC Class Codes: F25D 29/00 Arrangement or mounting of control or safety devices
• CPC Class Codes: G10K 11/17813 characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms
• CPC Class Codes: G10K 11/17817 between the output signals and the error signals, i.e. secondary path
• CPC Class Codes: G10K 11/17823 Reference signals, e.g. ambient acoustic environment
• CPC Class Codes: G10K 11/17853 of the filter
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17861 using additional means for damping sound, e.g. using sound absorbing panels
• CPC Class Codes: G10K 11/17879 using both a reference signal and an error signal
• CPC Class Codes: G10K 2210/1054 Refrigerators
• CPC Class Codes: G10K 2210/109 Compressors, e.g. fans
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10K 2210/3036 Modes, e.g. vibrational or spatial modes
• CPC Class Codes: G10K 2210/3045 Multiple acoustic inputs, single acoustic output

Abstract

A silencer attenuating a noise from a noise source to be ventilated of this invention comprises a machine compartment with a one-dimensional duct configuration whose sectional dimension is sufficiently small in comparison with the wavelength of the noise to be attenuated, a compressor and/or other machinery disposed within the machine compartment, an opening for dissipation of heat as disposed in a wall of the machine compartment and opening in a direction generally perpendicular to the direction of advance of sound within the machine compartment, a vibration pickup for detecting the vibration of the machinery corresponding to the output noise of the machinery, and a control circuit for processing output signals from the vibration pickup to drive a sound generator such as a speaker. The sound generator outputs a controlling signal dependent on the machine noise to cancel the noise about to emerge from the machine compartment.

Claims

1. A silencer attenuating noise from a noise source requiring ventilation, the silencer comprising:

a machine compartment with a one-dimensional duct configuration whose sectional dimension is sufficiently small in comparison with wavelength of the noise to be reduced, the noise source being disposed therein;

an opening for dissipation of heat as disposed in a wall of the machine compartment and opening in a direction generally perpendicular to the direction of advance of the noise within the machine compartment;

a vibration pickup means for detecting vibrations of the noise source, the vibration pickup means being attached to the noise source;

a control circuit for processing signal outputs of the vibration pickup means; and

a sound generator, such as a speaker, which is driven by output signals from the control circuit to output a controlling sound in the machine compartment and to cancel thereby the noise which is about to emerge from the opening.

2. A silencer according to claim 1, wherein the noise source is a compressor constituting a refrigerating cycle.

3. A silencer according to claim 2, wherein

the noise source additionally includes a suction pipe having a portion proximate to the compressor, and

the vibration pickup means is mounted on the portion of the suction pipe proximate to the compressor.

4. A silencer according to claim 2, wherein the compressor is disposed as far distant as possible from the opening.

5. A silencer according to claim 2, wherein

the compressor includes a cylindrical body, and

the vibration pickup means is mounted on the cylindrical body.

6. A silencer according to claim 5, wherein the vibration pickup means is for detecting vibrations of the compressor in a direction tangential to the cylindrical body.

7. A silencer according to claim 2, wherein

the compressor includes a motor segment, and

the vibration pickup means is mounted on the motor segment.

8. A silencer according to claim 7, wherein

the motor segment includes an end face, and

the vibration pickup means is mounted on the end face.

9. A silencer according tot any one of claims 1, 2, 3, 4, 5, 7 or 8, wherein the control circuit includes a transfer function applying means for applying a noise-attenuation transfer function G to cause the sound generator, such as a speaker, to output a controlling sound corresponding to the noise of the noise source to thereby cancel the noise about to emerge from the opening with the controlling sound.

11. A silencer attenuating a noise from a noise source to be ventilated, comprising:

a machine compartment with a one-dimensional duct configuration whose sectional dimension is sufficiently small in comparison with wavelength of the noise to be reduced;

a couple of openings for dissipation of heat as formed in opposed end portions of a wall of the machine compartment and opening in a direction generally perpendicular to the direction of advance of the noise in the machine compartment;

a compressor and other machinery as the noise source disposed in a central zone of the machine compartment;

a noise signal collecting means for detecting vibrations of the noise source;

a control circuit for processing output signals from the noise source signal collecting means, and

a sound generator, such as a speaker, which is disposed in a central zone within the machine compartment and driven by output signals from the control circuit to output a controlling sound within the machine compartment and thereby cancels the machine noise which is about to emerge from the couple of openings.

10. A silencer according to claim 13, wherein the transfer function applying means is for applying a transfer function G defined by:

space="preserve" listing-type="equation">G=-G.sub.MR /G.sub.AR

space="preserve" listing-type="equation">G.sub.MR =G.sub.SR /G.sub.SM

where G_SR is the acoustic transfer function between the noise source and the opening, G_AR is the acoustic transfer function between the sound generator, such as a speaker, and the opening, and G_SM is the transfer function between the noise source and the vibration pickup means.

12. A silencer according to claim 11 wherein the noise source signal collecting means includes a vibration pickup.

13. A silencer according to claims 11 or 12, wherein the control circuit includes a transfer function applying means for applying a noise-attenuation transfer function G to cause the sound generator, such as a speaker, to output a controlling sound corresponding to the noise of the noise source to thereby cancel the noise about to emerge from the couple of openings with the controlling sound.

14. A silencer according to claim 13, wherein the transfer function applying means is for applying a transfer function G defined by:

space="preserve" listing-type="equation">G=-G.sub.MR /G.sub.AR

space="preserve" listing-type="equation">G.sub.MR /G.sub.Sm

where G_SR is the acoustic transfer function between the noise source and the couple of openings, G_AR is the acoustic transfer function between the sound generator, such as a speaker, and the couple of openings, and G_SM is the transfer function between the the noise source and the noise signal collecting means.