US3819318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsating combustors
Assignee: Babcock International Ltd
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Filing: 1973-04-24
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Granted: 1974-06-25
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Expires: 1993-04-24
Abstract
Abstract A pulse combustion installation including a combustion chamber closed at one end and provided with a neck at the other end with an outlet duct extending therefrom. An inlet duct extending convergently to the neck and being co-axial and partly coextensive with the outlet duct at the neck. The inlet and outlet ducts and combustion chamber being of such length as to produce resonant conditions upon combustion of fluent fuel within the combustion chamber.
Inventors
- 👤 R Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:36
CPC Classifications
F; F23; F23C; F23C15/00; F02; F02G; F02G3/00
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
179 words
A pulse combustion installation including a tubular combustion chamber closed at one end and formed with a neck at the other end, a combustion gases outlet duct extending divErgently from the neck and co-axially therewith, a combustion air inlet duct extending convergently to the neck co-axially and partly co-extensively with the outlet duct at the neck, a transition region between the neck and an entry portion of the inlet duct having an aerodynamically unimpeded form relative to air flow toward the neck, means at the neck substantially sharp edged in a direction toward the combustion chamber interior arranged to cause a substantial contraction in the crosssectional area of gas flow stream out of the combustion chamber compared with the cross-sectional area of gas flow stream into the combustion chamber and an entry portion of the outlet duct arranged to direct combustion gases discharged from the combustion chamber to the outlet duct, the lengths of the inlet and outlet duct and the combustion chamber being such as to produce resonant conditions upon combustion of fluent fuel within the combustion chamber.
Claim 2
Dependent Claim
179 words
A pulse combustion installation including a tubular combustion chamber closed at one end and formed with a neck at the other end, a combustion gases outlet duct extending divErgently from the neck and co-axially therewith, a combustion air inlet duct extending convergently to the neck co-axially and partly co-extensively with the outlet duct at the neck, a transition region between the neck and an entry portion of the inlet duct having an aerodynamically unimpeded form relative to air flow toward the neck, means at the neck substantially sharp edged in a direction toward the combustion chamber interior arranged to cause a substantial contraction in the crosssectional area of gas flow stream out of the combustion chamber compared with the cross-sectional area of gas flow stream into the combustion chamber and an entry portion of the outlet duct arranged to direct combustion gases discharged from the combustion chamber to the outlet duct, the lengths of the inlet and outlet duct and the combustion chamber being such as to produce resonant conditions upon combustion of fluent fuel within the combustion chamber.
Claim 3
Dependent Claim
37 words
A pulse combustion installation as claimed in claim 1, wherein the junction of a wall of the combustion air inlet duct and a wall of the tubular combustion chamber forms a flat sharp-edged orifice at the neck.
Claim 4
Dependent Claim
52 words
A pulse combustion installation as claimed in claim 1, wherein at the junction of a wall of the combustion air inlet duct and a wall of the tubular combustion chamber the wall of the tubular combustion chamber is directed toward the combustion chamber interior such that a sharpedged re-entrant orifice is formed.
Claim 5
Dependent Claim
47 words
A pulse combustion installation as claimed in claim 2, wherein the ratio of the cross-sectional area of the outlet duct at the entry thereto perpendicular to gas flow in the duct to the cross-sectional area of the sharp-edged flat or re-entrant orifice is between 0.8 and 1.5.
Claim 6
Dependent Claim
48 words
A pulse combustion installation as claimed in claim 2 wherein the ratio of the cross-sectional area of the sharp-edged flat or re-entrant orifice to the crosssectional area of the outlet duct at the entry thereto perpendicular to gas flow in the duct is approximately 1.0 to 1.1 respectively.
Claim 7
Dependent Claim
46 words
A pulse combustion installation as claimed in any one of claim 2, wherein the ratio of the cross-sectional area of the sharp-edged orifice to the cross-sectional area of the inlet duct at the neck perpendicular to air flow in the duct is between 1.0 and 5.0.
Claim 8
Dependent Claim
37 words
A pulse combustion installation as claimed in claim 1 wherein the angle between a discharge portion of the inlet duct immediately adjacent the neck and the central axis of the outlet duct is between 45* and 60*.
Claim 9
Dependent Claim
35 words
A pulse combustion installation as claimed in claim 1, wherein the angle between a discharge portion of the inlet duct immediately adjacent the neck and the central axis of the outlet duct is approximately 52*.
Claim 10
Dependent Claim
41 words
A pulse combustion installation as claimed in claim 1, wherein the ratio of the length of a cylindrical duct acoustically equivalent to the outlet duct to the length of a cylindrical duct acoustically equivalent to the inlet duct is approximately 2.4.
Claim 11
Dependent Claim
28 words
A pulse combustion installation as claimed in claim 1, wherein the ratio of the combustion chamber diameter of axial length is between 1.0 and 2.0 and preferably 1.4.
Claim 12
Dependent Claim
44 words
A pulse combustion installation as claimed in claim 1, wherein a helmholtz resonator means aligned with the entry portion of the inlet duct is arranged to attenuate noise and recover part of the resonant energy by being tuned to the fundamental frequency of resonance.
Claim 13
Dependent Claim
21 words
A pulse combustion installation as claimed in claim 1, wherein the inlet duct extends around and coaxially of the outlet duct.
Claim 14
Dependent Claim
42 words
A pulse combustion installation as claimed in claim 12, wherein an axial passage is formed by radially extending webs intermediate the adjacent walls of the inlet and outlet ducts for the forced flow of air during establishment of combustion and resonant conditions.
Claim 15
Dependent Claim
57 words
A pulse combustion installation as claimed in claim 1, wherein the inlet duct is braNched into passageways swept through 180* to extend adjacent to the combustion chamber and parallel to the axis thereof such that air flow at the entry is in the same direction as the direction of flow of combustion gases in the outlet duct.
Claim 16
Dependent Claim
30 words
A pulse combustion installation as claimed in claim 14 wherein the inlet duct is branched into diametrically opposed pairs of passageways of generally rectangular cross-section remote from the entries thereto.
Claim 17
Dependent Claim
58 words
A pulse combustion installation as claimed in claim 15 wherein each passageway of one pair of passageways extends over about 120*-150* of arc and each passageway of the other pair of passageways extends over about 60* to 30* of arc and is arranged to receive a forced flow of air during the establishment of combustion and resonant conditions.
Claim 18
Dependent Claim
33 words
A pulse combustion installation as claimed in claim 15, wherein entries to one pair of passageways are of re-entrant form and the entries to the other pair of passageways are of bell-mouthed form.
Claim 19
Dependent Claim
28 words
A pulse combustion installation as claimed in claim 1, wherein a pressure jet atomising burner nozzle is positioned in the combustion chamber for the supply of fuel thereto.
Claim 20
Dependent Claim
45 words
A pulse combustion installation as claimed in claim 1, wherein the outlet duct is positioned within a combustion flue tube of a water heating unit, and the combustion gases are arranged to flow in heat exchange relationship with a body of water within the unit.
Claim 21
Dependent Claim
34 words
A pulse combustion installation as claimed in claim 19, wherein the combustion flue tube is provided with a closed end to form a resonant cavity to attenuate noise and assist recovery of resonant energy.
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) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |