US3572961A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compressor noise-suppression system
Assignee: Rohr Inc
•
Filing: 1969-07-09
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Granted: 1971-03-30
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Expires: 1989-07-09
Abstract
Abstract Basic purpose of system is to prevent ''''line of sight'''' emission of compressor whine sound waves out through entrance throat of typical engine cowl. Peripheral series of vanes pivoted at leading edge to inner wall of cowl swing toward axis to block axial emission of sound waves and also cut off ingress of air. Peripheral auxiliary air inlet passage means is provided at locus aft of leading edge to allow lateral inflow of air when normal path is blocked. A blocking ring normally overlies inlet passage and moves axially forward to uncover it. Deployment of ring causes deployment of vanes. Sound suppression surfacing is applied to rear faces of vanes and throat of auxiliary inlet passage. Total area of auxiliary passage is approximately equal to area of cowl inlet throat.
Inventors
- 👤 George E Medawar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:13
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; F02C7/045; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
165 words
A noise-suppression system for use in combination with a jet engine having a noise-producing air compressor at its forward end and encased in a streamlined housing, comprising: an annular cowl forming the forward end of said housing and having an annular leading edge; said cowl being generally cylindrical and coaxial with said compressor to define a generally cylindrical normally open conduit for rearward flow of ambient air into the compressor while allowing compressor noise to be emitted axially forward to the exterior; peripherally arranged auxiliary air inlet passage means extending through the wall of the cowl at a locus rearward of the leading edge; and multiple blocking means lying across said passage means in a first, stowed and blocking position; at least a part of said blocking means serving to prevent flow of air therethrough; said blocking means being movable to unblocking position to allow air to flow inward through said passage means and block the emission of sound waves axially forward through said conduit.
Claim 2
Dependent Claim
165 words
A noise-suppression system for use in combination with a jet engine having a noise-producing air compressor at its forward end and encased in a streamlined housing, comprising: an annular cowl forming the forward end of said housing and having an annular leading edge; said cowl being generally cylindrical and coaxial with said compressor to define a generally cylindrical normally open conduit for rearward flow of ambient air into the compressor while allowing compressor noise to be emitted axially forward to the exterior; peripherally arranged auxiliary air inlet passage means extending through the wall of the cowl at a locus rearward of the leading edge; and multiple blocking means lying across said passage means in a first, stowed and blocking position; at least a part of said blocking means serving to prevent flow of air therethrough; said blocking means being movable to unblocking position to allow air to flow inward through said passage means and block the emission of sound waves axially forward through said conduit.
Claim 3
Dependent Claim
57 words
A system as claimed in claim 1; said blocking means including slidable means lying across the passage means at the outer surface of the cowl and swingable means lying across the passage means at the inner surface of the cowl; said swingable means being movable to a deployed position extending inwardly toward the axis of the cowl.
Claim 4
Dependent Claim
47 words
A system as claimed in claim 2; including sound suppression surfacing on the portions of the swingable means which face toward the compressor in deployed position; and further sound suppression surfacing on the portions of the passage means which lie in opposition to the deployed swingable means.
Claim 5
Dependent Claim
46 words
A system as claimed in claim 1; said passage means comprising a substantially complete annular passage opening through the inner and outer surface of the cowl wall and shaped to define a generally conical rearwardly and inwardly directed flow path for entrance of the ambient air.
Claim 6
Dependent Claim
25 words
A system as claimed in claim 4; the inlet area of said annular passage being substantially equal to the frontal inlet area of said cowl.
Claim 7
Dependent Claim
120 words
A system as claimed in claim 4; said blocking means including a closure ring having a first, stowed position overlying the entrance to said passage and movable axially to a deployed position uncovering the entrance; said blocking means further including a plurality of elongate vanes spaced around the periphery of the inner surface of the cowl and extending in a first, stowed position in an axial direction across the exit from said passage; said vanes being pivotally mounted to said cowl at their leading edges about axes substantially tangential to the curvature of the cowl and swingable to deployed positions extending inwardly toward the cowl axis to act as barriers to forward axial emission of sound waves from the compressor.
Claim 8
Dependent Claim
32 words
A system as claimed in claim 6; said vanes iN deployed position extending inwardly and rearwardly to define a generally frustoconical contour and forming the forward wall of the inlet passage throat.
Claim 9
Dependent Claim
27 words
A system as claimed in claim 6; and common pilot-operable servo means to cause all of said blocking means to move between their stowed and deployed positions.
Claim 10
Dependent Claim
46 words
A system as claimed in claim 8; said servo means being directly connected to said ring to move it toward its first and second positions; and interconnecting means between the ring and the vanes to cause them to move in response to movement of the ring.
Claim 11
Dependent Claim
35 words
A system as claimed in claim 9; said interconnecting means including a cam and a cam follower configured to cause deployment of the vanes only during the final portion of the deployment of the ring.
Claim 12
Dependent Claim
43 words
A system as claimed in claim 6; and an air-diverting center body coaxial with said compressor and extending forward therefrom; the trailing edges of said vanes in deployed position contacting said center body to complete the blocking of said axially emitted sound waves.
Claim 13
Dependent Claim
30 words
A system as claimed in claim 11; said center body being generally circular in cross section and said trailing edges being arcuate to provide line contact with the center body.
Claim 14
Dependent Claim
37 words
A system as claimed in claim 6; the widths of said vanes being sufficient to provide overlapping of their margins in deployed position throughout substantially their entire lengths to insure impermeability to the passage of sound waves.
Claim 15
Independent Claim
77 words
A method of suppressing the noise produced by a jet engine compressor and emitted axially forwardly through the inlet of the throat of the cowl, said cowl having normally blocked lateral passageways for the flow of air into the throat, comprising: the steps during landing and takeoff of unblocking the passageways in the cowl for passing air laterally into the throat; and blocking the inlet throat against ingress of air and egress of axially directed sound waves.
Claim 16
Independent Claim
77 words
A method of suppressing the noise produced by a jet engine compressor and emitted axially forwardly through the inlet of the throat of the cowl, said cowl having normally blocked lateral passageways for the flow of air into the throat, comprising: the steps during landing and takeoff of unblocking the passageways in the cowl for passing air laterally into the throat; and blocking the inlet throat against ingress of air and egress of axially directed sound waves.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |