US3883324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for agglomerating dry dust particles in a gas stream and separation
Assignee: Bethlehem Steel Corp
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Filing: 1973-05-02
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Granted: 1975-05-13
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Expires: 1993-05-02
Abstract
Abstract Method and apparatus for improving the efficiency of dry dust recovery from moving gases. A constriction is located in a duct carrying ''''dirty'''' gas from a dust-producing industrial operation, such as, for example, a blast furnace, to a dust catcher. The constriction may be a central orifice plate or similar means which reduces the cross-sectional flow area in one portion of the duct to about one-fourth of the area of the remaining portions of the duct, and thereby accelerates the velocity of gas flow through that portion of the duct. The location of the constriction when used with a cyclone type dust catcher must be at least five duct diameters upstream of the dust catcher in order to increase dry dust collection and is preferably ten duct diameters upstream from the dust catcher.
Inventors
- 👤 Paul A Balla
- 👤 Charles C Oshinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:00
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/42
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
141 words
A METHOD FOR REMOVING DRY PARTICULATE MATERIAL FROM A GAS STREAM CONTAINING BOTH FINE AND COARSER PARTICULATES COMPRISING: A. PASSING THE GAS STREAM IN A SUBSTANTIALLY DRY STATE THROUGH A GAS CONDUIT AND THROUGH A CONSTRICTION IN SAID CONDUIT HAVING A CROSS SECTIONAL AREA NOT GREATER THAN ABOUT ONE QUARTER OF THE CROSS SECTIONAL AREA OF THE CONDUIT AND LOCATED WITHIN THE DUCT AT LEAST FIVE DUCT DIAMETERS UPSTREAM FROM A DRY DUST COLLECTOR AND HAVING A CROSS SECTIONAL AREA OF THE DUCT AND THE INITIAL VELOCITY THROUGH THE DUCT OF THE GAS STREAM SUCH AS TO CAUSE AN ABRUPT INCREASE IN VELOCITY OF SAID GAS STREAM AT LEAST 10,000 FPM AS IT PASSES THROUGH THE CONSTRUCTION, AND B. PASSING THE DRY GAS STREAM TO SAID DRY DUST CATCHER WHERE PARTICLES IN THE GAS STREAM ARE REMOVED IN A DRY STATE.
Claim 2
Independent Claim
141 words
A METHOD FOR REMOVING DRY PARTICULATE MATERIAL FROM A GAS STREAM CONTAINING BOTH FINE AND COARSER PARTICULATES COMPRISING: A. PASSING THE GAS STREAM IN A SUBSTANTIALLY DRY STATE THROUGH A GAS CONDUIT AND THROUGH A CONSTRICTION IN SAID CONDUIT HAVING A CROSS SECTIONAL AREA NOT GREATER THAN ABOUT ONE QUARTER OF THE CROSS SECTIONAL AREA OF THE CONDUIT AND LOCATED WITHIN THE DUCT AT LEAST FIVE DUCT DIAMETERS UPSTREAM FROM A DRY DUST COLLECTOR AND HAVING A CROSS SECTIONAL AREA OF THE DUCT AND THE INITIAL VELOCITY THROUGH THE DUCT OF THE GAS STREAM SUCH AS TO CAUSE AN ABRUPT INCREASE IN VELOCITY OF SAID GAS STREAM AT LEAST 10,000 FPM AS IT PASSES THROUGH THE CONSTRUCTION, AND B. PASSING THE DRY GAS STREAM TO SAID DRY DUST CATCHER WHERE PARTICLES IN THE GAS STREAM ARE REMOVED IN A DRY STATE.
Claim 3
Dependent Claim
246 words
An improved method for removing fine dry particulate material from a gas stream containing both fine and coarser dry particulates comprising: a. passing the gas stream containing said fine and coarser dry particulates into and at a predetermined velocity through a conduit having a predetermined cross sectional area, b. agglomerating the fine dry particulAte material with the coarser dry particulate material by passing the gas stream in a substantially dry state through an abrupt constriction in said conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and having a cross sectional area with respect to the cross sectional area of the conduit and the initial velocity through the conduit of the gas stream such as to cause an increase in velocity of of said gas stream to a velocity greater than about 6,000 to 10, 000 fpm as it passes through the constriction whereby the fine particles in the gas stream are accelerated to a velocity sufficiently greater than the coarser particulates such that a substantial portion of the fine particulates impact upon the coarser particulates with a force sufficient to cause agglomeration of the fine particulates with the coarser particulates, and c. subsequent to agglomeration of the particulates by passage through the constriction direction the gas stream containing the agglomerated particulates through the conduit into a cyclone type dry dust catcher positioned at least 5 conduit diameters from the said constriction in the said conduit.
Claim 4
Dependent Claim
246 words
An improved method for removing fine dry particulate material from a gas stream containing both fine and coarser dry particulates comprising: a. passing the gas stream containing said fine and coarser dry particulates into and at a predetermined velocity through a conduit having a predetermined cross sectional area, b. agglomerating the fine dry particulAte material with the coarser dry particulate material by passing the gas stream in a substantially dry state through an abrupt constriction in said conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and having a cross sectional area with respect to the cross sectional area of the conduit and the initial velocity through the conduit of the gas stream such as to cause an increase in velocity of of said gas stream to a velocity greater than about 6,000 to 10, 000 fpm as it passes through the constriction whereby the fine particles in the gas stream are accelerated to a velocity sufficiently greater than the coarser particulates such that a substantial portion of the fine particulates impact upon the coarser particulates with a force sufficient to cause agglomeration of the fine particulates with the coarser particulates, and c. subsequent to agglomeration of the particulates by passage through the constriction direction the gas stream containing the agglomerated particulates through the conduit into a cyclone type dry dust catcher positioned at least 5 conduit diameters from the said constriction in the said conduit.
Claim 5
Dependent Claim
22 words
A method according to claim 2 wherein the constriction in the duct is positioned at least 10 duct diameters from the cyclone.
Claim 6
Independent Claim
205 words
A method of removing fine particles from a gas stream laden with said particles comprising: a. moving said gas stream at a predetermined speed toward a vortex type dry dust catcher through a first passageway, b. precipitiously increasing the speed of movement of said gas through said first passageway by decreasing the effective cross-sectional area of said passageway by not less than three quarters within a minimal distance and proportional with respect to the cross-sectional area of said passageway and the initial speed of the gas through said passageway such that the speed of movement of said gas is increased to at least 6,000 to 10,000 feet per minute whereby particles of various sizes in the dust stream are momentarily accelerated to different speeds causing interception and impaction of said particles upon each other and agglomeration of said particles together, c. passing said gas stream through a second passageway expanded from the size of said constriction for a distance equal to at least 5 times the diameter of the said first passageway to allow turbulence in said gas stream occasioned by said precipitious increase in speed of said gas stream to subside, and d. passing said gas stream into said dry vortex type dust catcher.
Claim 7
Independent Claim
205 words
A method of removing fine particles from a gas stream laden with said particles comprising: a. moving said gas stream at a predetermined speed toward a vortex type dry dust catcher through a first passageway, b. precipitiously increasing the speed of movement of said gas through said first passageway by decreasing the effective cross-sectional area of said passageway by not less than three quarters within a minimal distance and proportional with respect to the cross-sectional area of said passageway and the initial speed of the gas through said passageway such that the speed of movement of said gas is increased to at least 6,000 to 10,000 feet per minute whereby particles of various sizes in the dust stream are momentarily accelerated to different speeds causing interception and impaction of said particles upon each other and agglomeration of said particles together, c. passing said gas stream through a second passageway expanded from the size of said constriction for a distance equal to at least 5 times the diameter of the said first passageway to allow turbulence in said gas stream occasioned by said precipitious increase in speed of said gas stream to subside, and d. passing said gas stream into said dry vortex type dust catcher.
Claim 8
Dependent Claim
127 words
Apparatus for removing dry particulate material from a gas stream in a substantially dry condition, comprising: a. a conduit through which the gas stream is passed, b. a constriction within the conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and being otherwise dimensioned relative to the velocity of the gas through the conduit such that the gas stream will attain a minimum velocity of 10,000 linear feet per minute through the constriction, and c. a dry dust catcher positioned within not less than five duct diameters of the said constriction and into which the gas stream is directed subsequent to passage through the constriction and from which the dry particulates are removed in a dry condition.
Claim 9
Dependent Claim
127 words
Apparatus for removing dry particulate material from a gas stream in a substantially dry condition, comprising: a. a conduit through which the gas stream is passed, b. a constriction within the conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and being otherwise dimensioned relative to the velocity of the gas through the conduit such that the gas stream will attain a minimum velocity of 10,000 linear feet per minute through the constriction, and c. a dry dust catcher positioned within not less than five duct diameters of the said constriction and into which the gas stream is directed subsequent to passage through the constriction and from which the dry particulates are removed in a dry condition.
Claim 10
Dependent Claim
209 words
An improved apparatus for removing dry particulate material from a gas stream containing fine and coarser particulates in a substantially dry condition comprising: a. a conduit having a predetermined cross sectional area through which the gas stream is passed at a predetermined velocity in a substantially dry condition, b. an abrupt constriction within the conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and being otherwise dimensioned relative to the velocity of the gas through the conduit such that the gas stream will attAin a minimum velocity of greater than about 6,000 to 10,000 linear feet per minute through the constriction whereby when the gas stream passes through said constriction the fine particulates in the gas stream are accelerated to a velocity sufficiently greater than the coarser particulates such that the fine particulates impact upon the coarser particulates with a force sufficient to cause agglomeration of the particulates, and c. a cyclone type dry dust catcher into which the gas stream is directed subsequent to passage through the constriction and from which the dry particulates are removed in a dry condition said dry dust catcher being positioned at least 5 conduit diameters from the constriction in the said conduit.
Claim 11
Dependent Claim
209 words
An improved apparatus for removing dry particulate material from a gas stream containing fine and coarser particulates in a substantially dry condition comprising: a. a conduit having a predetermined cross sectional area through which the gas stream is passed at a predetermined velocity in a substantially dry condition, b. an abrupt constriction within the conduit having a cross sectional area not greater than one quarter of the cross sectional area of the conduit and being otherwise dimensioned relative to the velocity of the gas through the conduit such that the gas stream will attAin a minimum velocity of greater than about 6,000 to 10,000 linear feet per minute through the constriction whereby when the gas stream passes through said constriction the fine particulates in the gas stream are accelerated to a velocity sufficiently greater than the coarser particulates such that the fine particulates impact upon the coarser particulates with a force sufficient to cause agglomeration of the particulates, and c. a cyclone type dry dust catcher into which the gas stream is directed subsequent to passage through the constriction and from which the dry particulates are removed in a dry condition said dry dust catcher being positioned at least 5 conduit diameters from the constriction in the said conduit.
Claim 12
Dependent Claim
18 words
Apparatus according to claim 6 wherein the constriction is positioned at least 10 duct diameters from the cyclone.
Claim 13
Dependent Claim
15 words
Apparatus according to claim 7 wherein the constriction in the conduit is an orifice plate.
References Cited (Backward Citations)
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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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |