US4798615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making a filter for molten metal having a high melting point
Assignee: Nippon Muki Co Ltd
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Filing: 1986-10-17
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Granted: 1989-01-17
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Expires: 2006-10-17
Abstract
Abstract A filter for molten metal having a high melting point is in the form of a net woven of glass yarns formed by twisting a multiplicity of glass fibers together. The glass fibers contain at least 75 wt. % of SiO 2 and are thermally cured at a thermal shrinkage of 2.5 to 15%. The thermal shrinkage is expressed by (l-l')/×100 % wherein l is the length of the fiber before the thermal cure, and l' is the length of the fiber as thermally cured.
Inventors
- 👤 Shigemi Fukuta
- 👤 Toshinari Amakasu
- 👤 Ken Ugata
- 👤 Shoichi Yoshino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:47
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/08; B01D39/086; B22; B22C; B22C9/00; B22C9/08; B22C9/086; D; D03; D03D; D03D15/00; D03D15/20; D03D15/242; D03D15/267; B01D2239/00; B01D2239/04; B01D2239/0457; B01D2239/0471; B01D2239/06; B01D2239/065; B01D2239/0654
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
A process for producing a filter in the form of a woven net of SiO 2 -containing glass fibers for filtering molten metal comprising the steps of: (a) weaving glass yarns into a netlike filter, each of the glass threads being prepared by bundling and twisting together glass fibers composed cheifly of silica, (b) subjecting the netlike filter to an acid treatment to increase the SiO 2 content of the glass fibers to at least 75 wt. % and (c) thermally curing the resulting filter to contract the pores in the glass fibers until a shrinkage of 2.5 to 15% is obtained, said shrinkage being expressed by (l-l')/×100 % wherein l is the length of the fiber before the thermal cure, and l' is the length of the thermally cured fiber.
Claim 2
Dependent Claim
131 words
A process for producing a filter in the form of a woven net of SiO 2 -containing glass fibers for filtering molten metal comprising the steps of: (a) weaving glass yarns into a netlike filter, each of the glass threads being prepared by bundling and twisting together glass fibers composed cheifly of silica, (b) subjecting the netlike filter to an acid treatment to increase the SiO 2 content of the glass fibers to at least 75 wt. % and (c) thermally curing the resulting filter to contract the pores in the glass fibers until a shrinkage of 2.5 to 15% is obtained, said shrinkage being expressed by (l-l')/×100 % wherein l is the length of the fiber before the thermal cure, and l' is the length of the thermally cured fiber.
Claim 3
Dependent Claim
26 words
A process as defined in claim 1 wherein the acid treatment is conducted by immersing the netlike filter in an acid solution containing a reaction accelerator.
Claim 4
Dependent Claim
18 words
A process as defined in claim 1 wherein the filter is thermally cured at 800° to 1100° C.
Claim 5
Dependent Claim
22 words
A process as defined in claim 1 further comprising the step of applying an acid or neutral binder to the glass fibers.
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) | 1992-01-17 | 1992-07-18 | 1993-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-17 | 1996-07-18 | 1997-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-17 | 2000-07-18 | 2001-01-17 | $7700.00 | Window Closed / Lapsed |