Patent US3921673A successfully refreshed from Google Patents.
US3921673A
Expired / Lapsed
US
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Protective insert for lined flanged conduit
Assignee: Dow Chemical Co
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Filing: 1973-05-29
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Granted: 1975-11-25
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Expires: 1993-05-29
Abstract
Abstract A substantial increase in life in flanged plastic lined conduit is obtained when an annular insert is employed at the juncture of the flange and the conduit, the annular insert having a generally inwardly facing curved surface and the plastic liner subsequently flanged over the curved insert.
Inventors
- 👤 Richard E Pero
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:38
CPC Classifications
F; F16; F16L; F16L23/00; F16L23/12; F16L23/125
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
141 words
In a lined conduit, the lined conduit comprising a rigid outer casing, the outer casing having at least one end, a conduit flange disposed on and affixed to said end, the conduit having a synthetic resinous thermoplastic liner, the liner adjacent said end additionally forming a generally radially extending liner flange disposed generally adjacent to the conduit flange, the improvement which comprises an annular inwardly facing groove defined by the junction of the conduit and the conduit flange has an annular insert disposed within the groove, the annular insert having a generally outwardly facing curved surface which provides a generally smooth transition surface between the inner surface of the conduit casing and the conduit flange disposed on said casing, thereby lessening failure of the liner in the region of said junction of the conduit and the condUit flange under service conditions.
Claim 2
Dependent Claim
141 words
In a lined conduit, the lined conduit comprising a rigid outer casing, the outer casing having at least one end, a conduit flange disposed on and affixed to said end, the conduit having a synthetic resinous thermoplastic liner, the liner adjacent said end additionally forming a generally radially extending liner flange disposed generally adjacent to the conduit flange, the improvement which comprises an annular inwardly facing groove defined by the junction of the conduit and the conduit flange has an annular insert disposed within the groove, the annular insert having a generally outwardly facing curved surface which provides a generally smooth transition surface between the inner surface of the conduit casing and the conduit flange disposed on said casing, thereby lessening failure of the liner in the region of said junction of the conduit and the condUit flange under service conditions.
Claim 3
Dependent Claim
15 words
The conduit of claim 1 wherein the annular insert is radially split at one location.
Claim 4
Dependent Claim
13 words
The conduit of claim 1 wherein the annular insert is a synthetic resin.
Claim 5
Dependent Claim
29 words
The conduit of claim 1 wherein the curved surface of the annular insert has a radius of from about 1/4 to three times the thickness of the thermoplastic lining.
References Cited (Backward Citations)
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Cited
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US3298716A
Cited
US3383750A
Cited
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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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |