US4589275A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pipe coating
Assignee: Kendall Co
•
Filing: 1984-07-13
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Granted: 1986-05-20
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Expires: 2004-07-13
Abstract
Abstract Pipe coating having a thermal insulating layer of polymeric material and an outer barrier layer is provided with an additional layer between the two layers to facilitate testing of the latter for discontinuities. The intermediate layer can be electroconductive, smooth-surfaced, or of color contrasting to that of the barrier layer.
Inventors
- 👤 Samuel J. Thomas
- 👤 James M. Robich
- 👤 Robert L. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:14
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/12; G01R31/1227; G01R31/1263; G01R31/50; G01R31/58
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
88 words
In a pipe coated with a thermal insulating layer of foamed plastic polymeric material having an irregular outer surface and an outer barrier layer of non-foamed plastic polymeric material, the improvement comprising an intermediate layer interposed between and bonded to said insulating layer and said outer barrier layer to facilitate detection of pinholes and other discontinuities in said outer barrier layer, said intermediate layer having an inner face which mates with the irregularities of said insulating layer and an outer face smooth and substantially free from said irregularities.
Claim 2
Dependent Claim
88 words
In a pipe coated with a thermal insulating layer of foamed plastic polymeric material having an irregular outer surface and an outer barrier layer of non-foamed plastic polymeric material, the improvement comprising an intermediate layer interposed between and bonded to said insulating layer and said outer barrier layer to facilitate detection of pinholes and other discontinuities in said outer barrier layer, said intermediate layer having an inner face which mates with the irregularities of said insulating layer and an outer face smooth and substantially free from said irregularities.
Claim 3
Dependent Claim
15 words
A coated pipe as claimed in claim 1 in which said intermediate layer is electroconductive.
Claim 4
Dependent Claim
90 words
In the method of detecting pinholes and other discontinuities in the outer barrier layer of metal pipe coated with a thermal insulating layer of foamed polymeric material having an irregular outer surface and an outer barrier layer of polymeric material which comprises measuring ultrasonic characteristics of said barrier layer, the improvement which comprises interposing between and bonding to said insulating layer and said outer barrier layer a layer of mastic which fills the irregularities of the surface of said insulating layer and which presents a substantially smooth even outer surface.
Claim 5
Dependent Claim
90 words
In the method of detecting pinholes and other discontinuities in the outer barrier layer of metal pipe coated with a thermal insulating layer of foamed polymeric material having an irregular outer surface and an outer barrier layer of polymeric material which comprises measuring ultrasonic characteristics of said barrier layer, the improvement which comprises interposing between and bonding to said insulating layer and said outer barrier layer a layer of mastic which fills the irregularities of the surface of said insulating layer and which presents a substantially smooth even outer surface.
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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) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |