US4812149A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hot inert gas purging for filter blowback process
Assignee: Westinghouse Electric Co LLC
•
Filing: 1987-12-03
•
Granted: 1989-03-14
•
Expires: 2007-12-03
Abstract
Abstract A filter cleaning process for filters for separating particulates from a hot gas stream using hollow, tubular filter elements. Blowback and hot purge gas systems provide for cleaning of the filter elements and maintenance of the blowback system clear of the solids or condensation products that might form during separation. The process is especially useful in filtering solids from a hot, corrosive gaseous stream, such as a zirconium tetrachloride process gaseous stream, where the gas stream contains gaseous constituents that are subject to condensation directly to a solid during separation of the particulates and prior to discharge from the filtering apparatus.
Inventors
- 👤 Rodney L. Griffin
- 👤 David F. Ciliberti
- 👤 Thomas E. Lippert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:50
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/42; B01D46/4263; B01D46/24; B01D46/2403; B01D46/2407; B01D46/56; B01D46/58; B01D46/66; B01D46/70; B01D46/71; C; C01; C01B; C01B25/00; C01B25/02; C01B25/027; C01G; C01G23/00; C01G23/02; C01G23/022; C01G23/024; C01G25/00; C01G25/04; B01D2273/00; B01D2273/20
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
136 words
In a process for filtering particulate materials from a hot gas stream of the type which contain gaseous constituents that have a condensation temperature and are subject to condensation or solids formation during separation of the particulate material through cooling of the gas stream, and in which ceramic filter and blowback gas ports and blowback conduits are utilized for cleaning said filter, and in which a purge gas flow which continually exits through the blowback gas ports is utilized; the improved method which comprises: preheating said purge gas flow to above the condensation temperature of said component of the gas stream which component is subject to condensation or solids formation during the separation of the particulate material through cooling of the gas stream, whereby condensation in the blowback gas ports and blowback conduits is substantially avoided.
Claim 2
Dependent Claim
136 words
In a process for filtering particulate materials from a hot gas stream of the type which contain gaseous constituents that have a condensation temperature and are subject to condensation or solids formation during separation of the particulate material through cooling of the gas stream, and in which ceramic filter and blowback gas ports and blowback conduits are utilized for cleaning said filter, and in which a purge gas flow which continually exits through the blowback gas ports is utilized; the improved method which comprises: preheating said purge gas flow to above the condensation temperature of said component of the gas stream which component is subject to condensation or solids formation during the separation of the particulate material through cooling of the gas stream, whereby condensation in the blowback gas ports and blowback conduits is substantially avoided.
Claim 3
Dependent Claim
13 words
The process of claim 1, wherein said purge gas is above 350° C.
Claim 4
Dependent Claim
15 words
The process of claim 1, wherein an inert gas is utilized as said purge gas.
Claim 5
Dependent Claim
18 words
The process of claim 1, wherein said gas stream contains a gaseous chloride of a group IV-B metal.
Claim 6
Dependent Claim
13 words
The process of claim 4, wherein said gas stream is principally zirconium tetrachloride.
Claim 7
Dependent Claim
16 words
The process of claim 3, wherein the ceramic in said ceramic filter is principally silicon carbide.
Claim 8
Dependent Claim
13 words
The process of claim 2, wherein said gas stream is principally titanium tetrachloride.
Claim 9
Dependent Claim
13 words
The process of claim 2, wherein said gas stream is principally elemental phosphorus.
Claim 10
Dependent Claim
17 words
The process of claim 5, wherein said purge gas is nitrogen which is heated above 450° C.
Claim 11
Dependent Claim
102 words
In a process for filtering particulate materials from a gas stream having a temperature of at least 450° C. said gas stream being of the type which contain at least one gaseous constituent that is subject to condensation or solids formation during separation of the particulate material through cooling of the gas stream and in which a ceramic filter and blowback gas ports are utilized, and utilizing a pulse of blowback gas for cleaning said filter and a purge gas flow which continually exits through the blowback gas ports; the improved method which comprises: preheating said purge gas to above 450° C.
Claim 12
Dependent Claim
102 words
In a process for filtering particulate materials from a gas stream having a temperature of at least 450° C. said gas stream being of the type which contain at least one gaseous constituent that is subject to condensation or solids formation during separation of the particulate material through cooling of the gas stream and in which a ceramic filter and blowback gas ports are utilized, and utilizing a pulse of blowback gas for cleaning said filter and a purge gas flow which continually exits through the blowback gas ports; the improved method which comprises: preheating said purge gas to above 450° C.
Claim 13
Dependent Claim
21 words
The process of claim 10, wherein said gas stream constituent that is subject to condensation or solids formation is zirconium tetrachloride.
Claim 14
Dependent Claim
11 words
The process of claim 11, wherein said purge gas is nitrogen.
Claim 15
Dependent Claim
21 words
The process of claim 10, wherein said gas stream constituent which is subject to condensation or solids formation is titanium tetrachloride.
Claim 16
Dependent Claim
21 words
The process of claim 10, wherein said gas stream constituent which is subject to condensation, or solids formation is elemental phosphorous.
Claim 17
Dependent Claim
12 words
The process of claim 10, wherein said blowback gas is not preheated.
References Cited (Backward Citations)
US24954A
Cited
USRE24954E
Cited
US2721626A
Cited
US3325979A
Cited
SU507337A1
Cited
US4343631A
Cited
US4735635A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |