US4073318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for wear-resistant ducts
Assignee: 3M Co
•
Filing: 1976-11-19
•
Granted: 1978-02-14
•
Expires: 1996-11-19
Abstract
Abstract A process is provided for applying refractory wear-resistant interlocking tile to the inner surface of a circular to elliptical tubular casing and securing them in position by exertion of centripetal force from intumescence of an insulative sheet material between the tile and the casing exerting substantially uniform centrifugal and centripetal forces.
Inventors
- 👤 James R. Close
- 👤 James R. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:19
CPC Classifications
F; F16; F16L; F16L59/00; F16L59/14; F16L58/00; F16L58/02; F16L58/04; F16L9/00; F16L9/14; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49863; Y10T29/49865; Y10T428/00; Y10T428/13; Y10T428/1303; Y10T428/16; Y10T428/163; Y10T428/164; Y10T428/166; Y10T428/25; Y10T428/251
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
49 words
As an article of manufacture a duct consisting essentially of casing, interlocked abrasion-resistant tile lining and expanded intumescent composition between said tile lining and said casing exerting forces thereon respectively centripetally and centrifugally of said tile lining in said casing of at least 2 Newtons per cm 2 .
Claim 2
Dependent Claim
49 words
As an article of manufacture a duct consisting essentially of casing, interlocked abrasion-resistant tile lining and expanded intumescent composition between said tile lining and said casing exerting forces thereon respectively centripetally and centrifugally of said tile lining in said casing of at least 2 Newtons per cm 2 .
Claim 3
Dependent Claim
163 words
A process for providing abrasion resistance to the inner surface of a hollow tube of round to elliptic cross-section comprising A. providing said tube internally with a first layer of insulative sheet material expandable to resilient mat means and a second layer of interlocking refractory abrasion resistant tile temporarily positioned inward of said first layer, clearances between said tube and said first and second layers being sufficiently large to permit relative movement between said tube and said second layer and not being greater than the expanded thickness of said insulative sheet material, and B. heating said tube under conditions of substantially uniform circumferential heat distribution with said first and second layers in position whereby expansion of said insulative sheet material is effected substantially uniformly so that force is exerted centripetally of said tube on said interlocking tile and centrifugally on said tube of at least 2 Newtons per cm 2 and sufficient to hold said tile in securely interlocked relationship within said tube.
Claim 4
Dependent Claim
163 words
A process for providing abrasion resistance to the inner surface of a hollow tube of round to elliptic cross-section comprising A. providing said tube internally with a first layer of insulative sheet material expandable to resilient mat means and a second layer of interlocking refractory abrasion resistant tile temporarily positioned inward of said first layer, clearances between said tube and said first and second layers being sufficiently large to permit relative movement between said tube and said second layer and not being greater than the expanded thickness of said insulative sheet material, and B. heating said tube under conditions of substantially uniform circumferential heat distribution with said first and second layers in position whereby expansion of said insulative sheet material is effected substantially uniformly so that force is exerted centripetally of said tube on said interlocking tile and centrifugally on said tube of at least 2 Newtons per cm 2 and sufficient to hold said tile in securely interlocked relationship within said tube.
Claim 5
Dependent Claim
29 words
The process according to claim 1 wherein at least said second layer is applied externally to a mandrel of evanescent composition and the assembly is inserted into the tube.
Claim 6
Dependent Claim
13 words
The process according to claim 1 wherein the intumescent sheet material comprises vermiculite.
References Cited (Backward Citations)
US2824033A
Cited
US3044499A
Cited
US3460305A
Cited
US3488040A
Cited
US3886024A
Cited
US3916057A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |