US4529662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Asbestos-free sheet material for spiral-wound gaskets
Assignee: T&N Materials Research Ltd
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Filing: 1983-11-10
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Granted: 1985-07-16
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Expires: 2003-11-10
Abstract
Abstract Non-asbestos flexible sheet material suitable for use in the manufacture of spiral wound gaskets is made by dewatering on a water-permeable conveyor a layer of aqueous slurry and compressing and drying the dewatered layer, the aqueous slurry employed being one that contains the following ingredients in the following proportions by dry weight: china clay 20-50% mica or chlorite 20-50% graphite 10-40% cellulose fibres 2-10% vitreous fibre in wool form 2-10% synthetic organic polymer binder 2-10%.
Inventors
- 👤 Robert A. Lancaster
- 👤 Noel C. McKenzie
- 👤 Brian Hargreaves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:36
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/63; D21H17/67; D21H17/68; F; F16; F16J; F16J15/00; F16J15/02; F16J15/06; F16J15/10; F16J15/12; F16J15/121; F16J15/125; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/936; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31692; Y10T428/31699; Y10T428/31703
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
64 words
Non-asbestos flexible sheet material made by dewatering on a water-permeable conveyor a layer of aqueous slurry and compressing and drying the dewatered layer, the aqueous slurry employed being one that contains the following ingredients in the following proportions by dry weight: china clay: 20-40% mica or chlorite: 20-50% graphite: 10-40% cellulose fibres: 2-10% vitreous fibre in wool form: 2-10% synthetic organic polymer binder: 2-10%.
Claim 2
Dependent Claim
64 words
Non-asbestos flexible sheet material made by dewatering on a water-permeable conveyor a layer of aqueous slurry and compressing and drying the dewatered layer, the aqueous slurry employed being one that contains the following ingredients in the following proportions by dry weight: china clay: 20-40% mica or chlorite: 20-50% graphite: 10-40% cellulose fibres: 2-10% vitreous fibre in wool form: 2-10% synthetic organic polymer binder: 2-10%.
Claim 3
Dependent Claim
14 words
A spiral wound gasket which incorporates non-asbestos flexible sheet material according to claim 1.
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) | 1988-07-15 | 1989-01-14 | 1989-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-15 | 1993-01-14 | 1993-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-15 | 1997-01-14 | 1997-07-16 | $7700.00 | Window Closed / Lapsed |