Patent US3695387A successfully refreshed from Google Patents.
US3695387A
Expired / Lapsed
US
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Sound suppression system for fan jet engines
Assignee: Rohr Inc
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Filing: 1970-09-08
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Granted: 1972-10-03
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Expires: 1990-09-08
Abstract
Abstract A sound suppression system for a fan jet engine having a primary nozzle for discharging engine exhaust gases and a secondary nozzle surrounding and spaced from the primary nozzle to form therewith an annular flow path for fan air surrounding the exhaust gas stream. A shroud is attached to and forms a continuation of the secondary nozzle to define a discharge zone which receives and controls the exhaust gas and air streams. A plurality of circumferentially spaced elongate ducts are pivotally connected at their forward ends to the shroud to swing between stowed position just outside of the shroud wall, to deployed position converging rearwardly with their aft ends substantially in contact with each other and with a coaxial bullet to partially block rearward flow of exhaust gas and to divert it radially outwardly into the air stream through divergent passages defined by the ducts. Each duct has a forwardly facing inlet port at its forward end and a rearwardly facing outlet port in its aft end. When deployed, fan air is ramfed into the former ports, flows through the ducts and is discharged into the exhaust gas stream from the latter ports. The result is a thorough intermixing of fan air and exhaust gas prior to leaving the shroud, thereby reducing temperature and velocity of the air-gas mixture and lowering jet noise.
Inventors
- 👤 Jack H Hilbig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:40
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/38; F02K1/383
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
184 words
A sound suppression system for use in combination with a fan jet engine having a rearwardly discharging primary nozzle for the turbine exhaust gas stream and a secondary nozzle surrounding the primary nozzle and radially spaced therefrom for rearward flow of the fan air stream around the exhaust gas stream, comprising: a shroud connected to the secondary nozzle and forming a continuation thereof and defining a discharge zone to receive and control the turbine exhaust gas and fan air streams, a plurality of ducts mounted within the discharge zone in circumferentially spaced relation about the shroud axis, each duct having an end thereof in one of such streams and being directed into the other stream, each duct having a port adjacent each end thereof and one end each of said ducts contacting each other near the center of the primary stream, said ports being located and directed to provide a ram-flow of a portion of said fan air stream into one of such ports, lengthwise through the duct, and out of the other of such ports directly into the center of the exhaust stream.
Claim 2
Dependent Claim
184 words
A sound suppression system for use in combination with a fan jet engine having a rearwardly discharging primary nozzle for the turbine exhaust gas stream and a secondary nozzle surrounding the primary nozzle and radially spaced therefrom for rearward flow of the fan air stream around the exhaust gas stream, comprising: a shroud connected to the secondary nozzle and forming a continuation thereof and defining a discharge zone to receive and control the turbine exhaust gas and fan air streams, a plurality of ducts mounted within the discharge zone in circumferentially spaced relation about the shroud axis, each duct having an end thereof in one of such streams and being directed into the other stream, each duct having a port adjacent each end thereof and one end each of said ducts contacting each other near the center of the primary stream, said ports being located and directed to provide a ram-flow of a portion of said fan air stream into one of such ports, lengthwise through the duct, and out of the other of such ports directly into the center of the exhaust stream.
Claim 3
Dependent Claim
34 words
A sound suppression system as claimed in claim 1 wherein each duct is mounted for movement between an operative position as defined in claim 1 and a stowed position substantially clear of both streams.
Claim 4
Dependent Claim
45 words
A system as claimed in claim 2, each duct in stowed position lying outside of the shroud wall to avoid interference with stream flow and an elongate, axially directed aperture in the shroud wall for each duct to move into the discharge zone during deployment.
Claim 5
Dependent Claim
38 words
A system as claimed in claim 3, a substantially closed shield overlying each aperture on the outer wall of the shroud to receive the stowed duct and to prevent leakage of the air stream through the shroud wall.
Claim 6
Dependent Claim
24 words
A system as claimed in claim 2, each duct being pivotally mounted adjacent one end thereof for swinging movement between stowed and deployed position.
Claim 7
Dependent Claim
50 words
A system as claimed in claim 5 including a lever arm on each duct, an axially movable drive ring encircling the shroud and a drive line connected to the lever arms to swing the ducts between stowed and deployed positions; and a plurality of actuators connected to the drive ring.
Claim 8
Dependent Claim
46 words
A system as claimed in claim 5, the pivotal mounting of each duct being adjacent its forward end, each duct being swingable to a rearwardly convergent deployed position with its forward end adjacent to the shroud wall and its aft end in the exhaust gas stream.
Claim 9
Dependent Claim
44 words
A system as claimed in claim 7, the port in the forward end of each duct being in the forward side to receive fan air, and the other port being in the aft side to discharge such fan air into the exhaust gas flow.
Claim 10
Dependent Claim
57 words
A system as claimed in claim 7, the aft ends of the ducts in deployed position being substantially in contact with each other to partially block rearward flow of exhaust gas and defining between them flow paths which diverge toward the shroud wall, serving to divert exhaust gas outwardly toward and into the surrounding fan air stream.
Claim 11
Dependent Claim
42 words
A system as claimed in claim 7, and a bullet mounted coaxially behind the engine to define an inner wall of the total flow path; the aft ends of the ducts in deployed condition substantially contacting both the bullet and each other.
Claim 12
Dependent Claim
25 words
A system as claimed in claim 1, each duct having a streamlined cross sectional shape with a rounded leading edge and a sharp trailing edge.
Claim 13
Dependent Claim
236 words
A sound suppression system for use in combination with a fan jet engine having a rearwardly discharging primary nozzle for the turbine exhaust gas stream and a secondary nozzle surrounding the primary nozzle and radially spaced therefrom for rearward flow of the fan air stream around the exhaust gas stream, comprising: a shroud connected to the secondary nozzle and forming a continuation thereof and defining a discharge zone to receive and control the turbine exhaust gas and fan air streams, and a plurality of elongate ducts mounted within the discharge zone in peripherally spaced relation around the shroud; each duct being pivotally mounted adjacent one end thereof to the shroud for swinging movement about a transverse axis in a radial plane containing the longitudinal axis of the shroud between a first, stowed position in which the longitudinal axis of each duct is generally parallel to the longitudinal axis of the shroud, and a second, deployed position in which each duct is inclined at a substantial angle to the axis of the shroud with one end each of said ducts contacting near the center of the primary stream, with one end thereof in the fan air stream, an open port being provided in each end of the duct, said ports being located and directed to provide a flow of a portion of one of the streams through the duct directly into the center of the exhaust stream.
Claim 14
Dependent Claim
236 words
A sound suppression system for use in combination with a fan jet engine having a rearwardly discharging primary nozzle for the turbine exhaust gas stream and a secondary nozzle surrounding the primary nozzle and radially spaced therefrom for rearward flow of the fan air stream around the exhaust gas stream, comprising: a shroud connected to the secondary nozzle and forming a continuation thereof and defining a discharge zone to receive and control the turbine exhaust gas and fan air streams, and a plurality of elongate ducts mounted within the discharge zone in peripherally spaced relation around the shroud; each duct being pivotally mounted adjacent one end thereof to the shroud for swinging movement about a transverse axis in a radial plane containing the longitudinal axis of the shroud between a first, stowed position in which the longitudinal axis of each duct is generally parallel to the longitudinal axis of the shroud, and a second, deployed position in which each duct is inclined at a substantial angle to the axis of the shroud with one end each of said ducts contacting near the center of the primary stream, with one end thereof in the fan air stream, an open port being provided in each end of the duct, said ports being located and directed to provide a flow of a portion of one of the streams through the duct directly into the center of the exhaust stream.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |