US3566811A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air damper
Assignee: Alcan Research and Development Ltd
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Filing: 1969-03-12
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Granted: 1971-03-02
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Expires: 1989-03-12
Abstract
Abstract There is disclosed a damper for use in furnace flues wherein opposed sheets or curtains of air are directed from ducts on opposite sides of a flue toward the center at a downward slope, and regulation thereof by controlling the damper by varying the air flow to the ducts.
Inventors
- 👤 David J Tidd
- 👤 Lawrence E Carroll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:34
CPC Classifications
F; F27; F27D; F27D17/00; F27D17/30; F23; F23L; F23L13/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
204 words
A flue damper comprising: a. a flue having four substantially flat walls forming an enclosed flue passage with two walls at substantially right angles to the other two; b. an air duct arranged along the full length of two opposed walls having openings therein arranged to discharge air therefrom at an angle that slopes downwardly so that air streams from the opposed ducts intersect at a level below the ducts and about midway between the two; c. said ducts being recessed from the vertical plane of the flue walls on which they are located; d. the flue walls being sloped upwardly and outwardly from the flue passage toward the respective ducts at a level where the air discharge from the duct sweeps the said sloping surfaces whereby flue gases rising along said walls is confined against lateral flow toward the ducts; e. means for supplying air under pressure to each of the ducts, the openings in the ducts being so arranged that there is a substantially continuous curtain of air projected crosswise into the flue from the inner edge of the sloping surface to at least the said midplane of the flue with the curtain being coextensive with the width of the flue wall.
Claim 2
Dependent Claim
204 words
A flue damper comprising: a. a flue having four substantially flat walls forming an enclosed flue passage with two walls at substantially right angles to the other two; b. an air duct arranged along the full length of two opposed walls having openings therein arranged to discharge air therefrom at an angle that slopes downwardly so that air streams from the opposed ducts intersect at a level below the ducts and about midway between the two; c. said ducts being recessed from the vertical plane of the flue walls on which they are located; d. the flue walls being sloped upwardly and outwardly from the flue passage toward the respective ducts at a level where the air discharge from the duct sweeps the said sloping surfaces whereby flue gases rising along said walls is confined against lateral flow toward the ducts; e. means for supplying air under pressure to each of the ducts, the openings in the ducts being so arranged that there is a substantially continuous curtain of air projected crosswise into the flue from the inner edge of the sloping surface to at least the said midplane of the flue with the curtain being coextensive with the width of the flue wall.
Claim 3
Dependent Claim
193 words
The combination with a furnace flue having four walls forming a flue passage, of an air duct extending along each of two opposite walls recessed outwardly from the flue-forming faces of the walls and entirely clear of a straight line flow of gases up the flue, the walls of the flue in which the ducts are positioned being chamfered to form an upwardly and outwardly-sloping surface between the flue passage and said ducts, means for supplying air under pressure to the two ducts, the ducts having openings therein arranged to direct air down across the sloping chamfered surface and form a continuous curtain by the time the air reaches the lower edge of said surface to substantially preclude the up-flow of gases from the flue over said sloping surface, the curtain extending the full distance between the Other two walls of the flue, said openings in the ducts comprising closely-spaced holes arranged to generate spaced jets of air with outwardly-narrowing open spaces between the jets, the ducts being recessed sufficiently from the flue passage so that the open spaces between the jets do not project beyond the inner edge of the sloping surface.
Claim 4
Dependent Claim
193 words
The combination with a furnace flue having four walls forming a flue passage, of an air duct extending along each of two opposite walls recessed outwardly from the flue-forming faces of the walls and entirely clear of a straight line flow of gases up the flue, the walls of the flue in which the ducts are positioned being chamfered to form an upwardly and outwardly-sloping surface between the flue passage and said ducts, means for supplying air under pressure to the two ducts, the ducts having openings therein arranged to direct air down across the sloping chamfered surface and form a continuous curtain by the time the air reaches the lower edge of said surface to substantially preclude the up-flow of gases from the flue over said sloping surface, the curtain extending the full distance between the Other two walls of the flue, said openings in the ducts comprising closely-spaced holes arranged to generate spaced jets of air with outwardly-narrowing open spaces between the jets, the ducts being recessed sufficiently from the flue passage so that the open spaces between the jets do not project beyond the inner edge of the sloping surface.
Claim 5
Dependent Claim
74 words
The combination defined in claim 2 wherein the means for supplying air to the ducts comprises a blower and a pipe for conveying air from the blower to both ducts, and valve means for variably controlling the flow of air to both ducts, said valve means being responsive to gas pressure in the furnace of which the flue is a part whereby the valve means are controlled according to pressure conditions in the furnace.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |