Patent US4384905A successfully refreshed from Google Patents.
US4384905A
Expired / Lapsed
US
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Method of forming an insulating pipe
Assignee: INPAL INDUSTRIES
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Filing: 1981-04-03
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Granted: 1983-05-24
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Expires: 2001-04-03
Abstract
Abstract The thermally insulated conduit includes an internal pipe, an external pipe, and an insulating foam which fills the interspace formed between these pipes. An electric grid, consisting of a wire heater, extends through the tubular space and is attached to the outer periphery of the internal pipe. The insulating foam used is made from a base of epoxy resins which are polymerized and hardened by an exothermic chemical reaction. The electric grid is used to heat the fluid contained in the internal pipe when the conduit is operated.
Inventors
- 👤 Rene Gros
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:40
CPC Classifications
F; F16; F16L; F16L59/00; F16L59/14; F16L59/16; F16L59/18; F16L59/20; B; B29; B29C; B29C44/00; B29C44/02; B29C44/12; B29C44/1228; B29C44/1242; B29C44/1295; F16L53/00; F16L53/30; F16L53/35; F16L53/38; F16L59/02; F16L59/021; F16L59/04; F16L59/12; Y; Y10; Y10S; Y10S264/00; Y10S264/13; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49888
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
62 words
A method of forming an insulating pipe comprising: mounting a wire heater along the periphery of an internal pipe; surrounding said internal pipe with a larger diameter external pipe to form a tubular space between said internal pipe and said external pipe, whereby said wire heater is disposed in said tubular space; and introducing an insulating epoxy foam in said tubular space.
Claim 2
Independent Claim
62 words
A method of forming an insulating pipe comprising: mounting a wire heater along the periphery of an internal pipe; surrounding said internal pipe with a larger diameter external pipe to form a tubular space between said internal pipe and said external pipe, whereby said wire heater is disposed in said tubular space; and introducing an insulating epoxy foam in said tubular space.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 1 wherein said internal pipe is centrally disposed in said external pipe.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1 further comprising before the introducing step: tilting said internal and external pipes.
Claim 5
Dependent Claim
25 words
A method as claimed in claim 3 wherein during said introducing step, said insulating epoxy foam is injected from the bottom of said tubular space.
Claim 6
Dependent Claim
26 words
A method as claimed in claim 2 further comprising before said surrounding step: placing at least one radial spacer on the periphery of the internal pipe.
Claim 7
Independent Claim
218 words
A method of connecting two internal pipes, each of said two internal pipes having an insulated section and at least one adjacent uninsulated end section, each of said insulated sections having an external pipe associated therewith, whereby each of said end sections extends beyond the end of each of said associated external pipes, and each of said internal pipes having a heater element along the periphery thereof, said heater elements each having a free end attachable to the free end of another heater element; said method comprising the steps of: sealingly joining said uninsulated end sections of one of said two internal pipes to said uninsulated end sections of the other of said internal pipes thereby joining said two internal pipes; connecting the free end of each of said heater elements on said joined internal pipes to one another; connecting said insulated section of one of said two internal pipes to said insulated section of the other of said two internal pipes with a plastic sleeve such that said internal pipes extend beyond each of said external pipes and each of said insulated sections, said plastic sleeve partially covering each of said external pipes and having a longitudinal slot therebetween, said plastic sleeve further overlapping each of said external pipes; and introducing epoxy resin foam inside said sleeve.
Claim 8
Independent Claim
218 words
A method of connecting two internal pipes, each of said two internal pipes having an insulated section and at least one adjacent uninsulated end section, each of said insulated sections having an external pipe associated therewith, whereby each of said end sections extends beyond the end of each of said associated external pipes, and each of said internal pipes having a heater element along the periphery thereof, said heater elements each having a free end attachable to the free end of another heater element; said method comprising the steps of: sealingly joining said uninsulated end sections of one of said two internal pipes to said uninsulated end sections of the other of said internal pipes thereby joining said two internal pipes; connecting the free end of each of said heater elements on said joined internal pipes to one another; connecting said insulated section of one of said two internal pipes to said insulated section of the other of said two internal pipes with a plastic sleeve such that said internal pipes extend beyond each of said external pipes and each of said insulated sections, said plastic sleeve partially covering each of said external pipes and having a longitudinal slot therebetween, said plastic sleeve further overlapping each of said external pipes; and introducing epoxy resin foam inside said sleeve.
Claim 9
Dependent Claim
52 words
A method as claimed in claim 6 further comprising after the introducing step: injecting inert gas into said epoxy resin foam to nucleate the foam and further reduce its density; circulating hot water in said internal pipe; and heating said internal pipe to avoid a skinning reaction of said epoxy resin foam.
Claim 10
Dependent Claim
18 words
A method as claimed in claim 1 wherein said external pipe is concentrically mounted with said internal pipe.
Claim 11
Dependent Claim
22 words
A method as claimed in claim 6 wherein each of said external pipes are concentrically mounted with each of said internal pipes.
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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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |