US3962081A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic foam filter
Assignee: Rio Tinto Switzerland AG
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Filing: 1975-03-28
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Granted: 1976-06-08
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Expires: 1995-03-28
Abstract
Abstract The disclosure teaches an improved ceramic foam filter particularly useful for filtering molten metal, and also a method for filtering molten metal. The filter is characterized by a combination of properties which makes it particularly suitable for use in filtering molten metal.
Inventors
- 👤 John C. Yarwood
- 👤 James E. Dore
- 👤 Robert K. Preuss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:17
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/06; C04B38/0615; B; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2068; B01D39/2093; B22; B22D; B22D43/00; B22D43/001; B22D43/004; C04B35/00; C04B35/01; C04B35/10; C22; C22B; C22B21/00; C22B21/06; C22B21/066; C22B9/00; C22B9/02; C22B9/023; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
91 words
A ceramic foam filter for use in filtering molten metal having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 8000 × 10 - 7 cm.sup. 2, a porosity of 0.80 to 0.95, a pore size of 5 to 45 pores per linear inch and a thickness of from 1/2 4 inches, said filter having substantial structural uniformity with a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 2
Dependent Claim
91 words
A ceramic foam filter for use in filtering molten metal having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 8000 × 10 - 7 cm.sup. 2, a porosity of 0.80 to 0.95, a pore size of 5 to 45 pores per linear inch and a thickness of from 1/2 4 inches, said filter having substantial structural uniformity with a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 3
Dependent Claim
24 words
A filter according to claim 1 wherein said ceramic foam filter has a gradation of properties from coarse to fine throughout the thickness thereof.
Claim 4
Dependent Claim
98 words
A filter according to claim 1 having a gradation of properties throughout the thickness thereof, with one side of said filter having an air permeability in the range of 2500 to 8000 × 10 - 7 cm 2 , a porosity of 0.90 to 0.95 and a pore size of 5 to 20 pores per linear inch, and the opposite side of said filter having an air permeability of from 400 to 2500 × 10 - 7 cm 2 , a porosity of 0.80 to 0.95 and a pore size of 20 to 45 pores per linear inch.
Claim 5
Dependent Claim
93 words
A ceramic foam filter for use in filtering molten metal having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 2500 × 10 - 7 cm 2 , a porosity of 0.80 to 0.95, a pore size of 20 to 45 pores per linear inch and a thickness of from 1/2 to 4 inches, said filter having substantial structural uniformity with a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 6
Dependent Claim
93 words
A ceramic foam filter for use in filtering molten metal having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 2500 × 10 - 7 cm 2 , a porosity of 0.80 to 0.95, a pore size of 20 to 45 pores per linear inch and a thickness of from 1/2 to 4 inches, said filter having substantial structural uniformity with a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 7
Dependent Claim
22 words
A filter according to claim 4 having an air permeability of from 1000 to 1500 × 10 - 7 cm 2 .
Claim 8
Dependent Claim
14 words
A filter according to claim 4 having a porosity of from 0.85 to 0.90.
Claim 9
Dependent Claim
19 words
A filter according to claim 4 having a pore size of from 25 to 35 pores per linear inch.
Claim 10
Dependent Claim
15 words
A filter according to claim 4 having a thickness of from 11/2 to 21/2 inches.
Claim 11
Dependent Claim
92 words
A ceramic foam filter having substantial structural uniformity for use in filtering molten aluminum having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability of from 1000 to 1500 × 10 - 7 cm 2 , a porosity of from 0.85 to 0.90, a pore size of from 25 to 35 pores per linear inch and a thickness of from 11/2 to 21/2 inches, said filter having a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 12
Dependent Claim
92 words
A ceramic foam filter having substantial structural uniformity for use in filtering molten aluminum having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability of from 1000 to 1500 × 10 - 7 cm 2 , a porosity of from 0.85 to 0.90, a pore size of from 25 to 35 pores per linear inch and a thickness of from 11/2 to 21/2 inches, said filter having a plurality of homogeneously distributed pore blockages throughout the foam.
Claim 13
Independent Claim
141 words
A method of filtering molten metal through a disposable filter which comprises: A providing a mass of molten metal; B providing a ceramic foam filter having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 8000 × 10 - 7 cm 2 , a porosity of 0.80 to 0.95, a pore size of 5 to 45 pores per linear inch and a thickness of from 1/2 to 4 inches and having substantial structural uniformity with a plurality of homogeneous pore blockages throughout the foam; and C pouring said molten metal through said material at a rate of from 5 to 50 cubic inches per square inch of filter area per minute, thereby removing entrained solids from the molten metal.
Claim 14
Independent Claim
141 words
A method of filtering molten metal through a disposable filter which comprises: A providing a mass of molten metal; B providing a ceramic foam filter having an open cell structure characterized by a plurality of interconnected voids surrounded by a web of said ceramic, said filter having an air permeability in the range of from 400 to 8000 × 10 - 7 cm 2 , a porosity of 0.80 to 0.95, a pore size of 5 to 45 pores per linear inch and a thickness of from 1/2 to 4 inches and having substantial structural uniformity with a plurality of homogeneous pore blockages throughout the foam; and C pouring said molten metal through said material at a rate of from 5 to 50 cubic inches per square inch of filter area per minute, thereby removing entrained solids from the molten metal.
Claim 15
Dependent Claim
57 words
A method according to claim 10 including the step of preliminarily filtering the molten metal through a relatively coarse ceramic foam filter having an air permeability of 2500 to 8000 × 10 - 7 cm 2 , a porosity of from 0.90 to 0.95, and a pore size of from 5 to 20 pores per linear inch.
Claim 16
Dependent Claim
20 words
A method according to claim 11 wherein said preliminary filtration utilizes a series of ceramic foam filters of decreasing porosity.
Claim 17
Dependent Claim
29 words
A method according to claim 11 wherein said preliminary filtration utilizes a single ceramic foam filter having a gradation of properties from coarse to fine throughout the thickness thereof.
Claim 18
Dependent Claim
12 words
A method according to claim 10 wherein said molten metal is aluminum.
References Cited (Backward Citations)
US3893917A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-08 | 1979-12-08 | 1980-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-08 | 1983-12-08 | 1984-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-08 | 1987-12-08 | 1988-06-08 | $7700.00 | Window Closed / Lapsed |