Patent US3939874A successfully refreshed from Google Patents.
US3939874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
External pipe coatings for a reinforced pipe
Assignee: British Gas PLC
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Filing: 1974-02-19
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Granted: 1976-02-24
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Expires: 1994-02-19
Abstract
Abstract Metal pipes are protected from corrosion by externally coating the pipe with a layer of coal tar and wrapping the pipe with at least one extensible material which is porous to allow the coal tar to pass through to form a layer on the outside. This type of wrap avoids any cracking of the protective materials during the commissioning and operation of the pipe.
Inventors
- 👤 David Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:16
CPC Classifications
F; F16; F16L; F16L58/00; F16L58/02; F16L58/16; F16L58/04; F16L58/12; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31717
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
In a metal pipe for the transmission of a fluid under pressure, the exterior of said metal pipe being coated with a reinforced protective layer comprising coal tar for corrosion protection reinforced with a layer of reinforcement fiber, the improvement wherein resistance to cracking and failure of the protective layer due to strain on the metal pipe are increased by utilizing, as the reinforcement fiber, a layer of longitudinally extensible porous synthetic organic polymer tissue and a layer of longitudinally extensible glass based fabric, both of said layers of reinforcement fiber being wrapped around the pipe in contact with said coal tar layer whereby the coal tar passes freely through to form a second layer of coal tar on the outside of said organic polymer tissue.
Claim 2
Dependent Claim
126 words
In a metal pipe for the transmission of a fluid under pressure, the exterior of said metal pipe being coated with a reinforced protective layer comprising coal tar for corrosion protection reinforced with a layer of reinforcement fiber, the improvement wherein resistance to cracking and failure of the protective layer due to strain on the metal pipe are increased by utilizing, as the reinforcement fiber, a layer of longitudinally extensible porous synthetic organic polymer tissue and a layer of longitudinally extensible glass based fabric, both of said layers of reinforcement fiber being wrapped around the pipe in contact with said coal tar layer whereby the coal tar passes freely through to form a second layer of coal tar on the outside of said organic polymer tissue.
Claim 3
Dependent Claim
21 words
An improved metal pipe according to claim 1 wherein, said layer of synthetic organic polymer tissue is pre-impregnated with coal tar.
Claim 4
Dependent Claim
41 words
An improved metal pipe according to claim 1 wherein said reinforcement fiber includes a further layer of longitudinally extensible knitted glass fabric reinforcement wrapped outside said metal pipe and a further coal tar layer interposed between the glass fabric reinforcement layers.
Claim 5
Dependent Claim
20 words
An improved metal pipe according to claim 3 wherein the outermost glass fabric reinforcement layer is pre-impregnated with coal tar.
Claim 6
Dependent Claim
54 words
A metal pipe according to claim 1 wherein the porous organic polymer tissue comprises a synthetic organic polymer tissue comprising a polyester/polyamide bi-component filament yarn manufactured as a tissue fabric to 100 grams/meters 2 fabric weight resulting in a material with approximately 30% longitudinal extension at a failure load of about 60 newtons/centimeters width.
Claim 7
Dependent Claim
53 words
A metal pipe according to claim 2 wherein the glass based material is a warp knitted - E glass yarn composed of 204 filaments per yarn, knitted to 180 grams/meters 2 fabric weight, resulting in a material with a longitudinal extensibility of about 25% and a failure load of about 20 newtons/centimeters width.
References Cited (Backward Citations)
US2828798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |