EP0226410A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of making a plastic-lined pipe
Assignee: DuPont Canada Inc
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Filing: 1986-12-05
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Granted: —
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Expires: 2006-12-05
Abstract
Abstract A method for lining tubular structures comprises stretching a pipe, formed from thermoplastic material and having an outer diameter greater than the internal diameter of the tubular structure, to the extent that the outer diameter of the pipe is less than the internal diameter of the tube. The tube is then placed over the stretched pipe and the tension in the stretched pipe is released. The stretched pipe contracts longitudinally and expands readially against the inside of the tubular structure, thereby forming a liner. In an emodiment, the tubular structure (30) is a steel pipe and the thermoplastic pipe (20) is a polyethylene pipe. The thermoplastic pipe (20) is stretched by anchoring barbed couplers (23, 24) in the ends (21, 22) of the pipe, inserting a pushrod (27) through the coupler (23) to abut a member (26) anchored in the coupler (24), and screwing a bolt (28) into coupler (23) to abut and push the end of the pushrod (27) until the required stretching of the pipe (20) has been achieved.
Inventors
- 👤 John Rowson Thompson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 11:21
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/22; B29C63/00; B29C63/26; B29C63/34
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
152 words
A method for producing a tubular structure lined with thermoplastic polymer, the method comprising the steps of: (1) providing a pipe liner of thermoplastic polymer having an outside diameter greater than the inside diameter of the tubular structure to be lined, (2) reducing the outer diameter of the pipe liner to less than the inside diameter of the tubular structure to be lined, and (3) inserting the pipe liner inside the tubular structure to be lined, characterized in that: (a) the pipe liner is stretched in a longitudinal direction under sufficient tension to reduce the outer diameter of the liner to less than the inside diameter of the tubular structure, (b) the tension on the stretched pipe liner is maintained during the insertion step, and (c) the tension on the stretched pipe liner is released to allow it to contract longitudinally and expand radially against the inside wall of the tubular structure.
Claim 2
Independent Claim
152 words
A method for producing a tubular structure lined with thermoplastic polymer, the method comprising the steps of: (1) providing a pipe liner of thermoplastic polymer having an outside diameter greater than the inside diameter of the tubular structure to be lined, (2) reducing the outer diameter of the pipe liner to less than the inside diameter of the tubular structure to be lined, and (3) inserting the pipe liner inside the tubular structure to be lined, characterized in that: (a) the pipe liner is stretched in a longitudinal direction under sufficient tension to reduce the outer diameter of the liner to less than the inside diameter of the tubular structure, (b) the tension on the stretched pipe liner is maintained during the insertion step, and (c) the tension on the stretched pipe liner is released to allow it to contract longitudinally and expand radially against the inside wall of the tubular structure.
Claim 3
Independent Claim
88 words
A method for producing a tubular structure lined with thermoplastic polymer, the method comprising in sequence: (1) providing a pipe liner of synthetic thermoplastic polymer having an outside diameter larger than the inside diameter of the tubular structure to be lined, (2) reducing the diameter of said liner, so that the reduced outside diameter of said liner is sufficiently smaller than the inside diameter of the tubular structure to be lined that the liner readily passes through the tubular structure, and (3) inserting the pipe liner inside the
Claim 4
Independent Claim
88 words
A method for producing a tubular structure lined with thermoplastic polymer, the method comprising in sequence: (1) providing a pipe liner of synthetic thermoplastic polymer having an outside diameter larger than the inside diameter of the tubular structure to be lined, (2) reducing the diameter of said liner, so that the reduced outside diameter of said liner is sufficiently smaller than the inside diameter of the tubular structure to be lined that the liner readily passes through the tubular structure, and (3) inserting the pipe liner inside the
Claim 5
Dependent Claim
115 words
tubular structure to be lined, characterized in that: (a) said pipe liner has an original outside diameter from about 2 percent to about 6 percent larger than the inside diameter of the tubular structure to be lined, (b) the diameter of the liner is reduced by applying tension in a longitudinal direction to the liner, so that the elongation of the liner is below the upper limit of the elastic-plastic range for the polymer of the liner, (c) the tension on the liner is maintained during the insertion step, and (d) the tension on the liner is released to allow it to contract longitudinally and expand radially against the inside wall of the tubular structure.
Claim 6
Dependent Claim
115 words
tubular structure to be lined, characterized in that: (a) said pipe liner has an original outside diameter from about 2 percent to about 6 percent larger than the inside diameter of the tubular structure to be lined, (b) the diameter of the liner is reduced by applying tension in a longitudinal direction to the liner, so that the elongation of the liner is below the upper limit of the elastic-plastic range for the polymer of the liner, (c) the tension on the liner is maintained during the insertion step, and (d) the tension on the liner is released to allow it to contract longitudinally and expand radially against the inside wall of the tubular structure.
Claim 7
Independent Claim
16 words
The method according to any of the preceding claims wherein the thermoplastic polymer is a polyolefin.
Claim 8
Dependent Claim
30 words
The method according to Claim 4, wherein the polyolefin is a homopolymer of ethylene or a copolymer of ethylene and at least one alpha-olefin of 4 to 10 carbon atoms.
Claim 9
Dependent Claim
15 words
The method according to Claim 1 or Claim 2, wherein the thermoplastic polymer is nylon.
Claim 10
Dependent Claim
13 words
The method according to Claim 5 wherein the nylon polymer is nylon 6,6.
Claim 11
Independent Claim
18 words
The method according to any of the preceding claims carried out at a temperature from -20°C to 30°C.
Claim 12
Independent Claim
26 words
The method according to any of the preceding claims wherein the inside diameter of the tubular structure is from about 13 mm to about 300 mm.
Claim 13
Independent Claim
22 words
The method according to any of the preceding claims wherein the pipe liner is elongated by no more than about 20 percent.
Claim 14
Independent Claim
34 words
The method according to any of the preceding claims wherein the pipe liner has an initial outside diameter from about 2 percent to 6 percent larger than the inside diameter of the tubular structure.
Claim 15
Independent Claim
23 words
The method according to any of the preceding claims wherein the pipe liner is maintained under tension for no more than 1 hour.
Claim 16
Dependent Claim
43 words
The method according to Claim 1 or Claim 2, wherein the steps are repeated using a second pipe liner of thermoplastic polymer, said second pipe liner having an outside diameter greater than the inside diameter of the first pipe liner of thermoplastic polymer.
Claim 17
Dependent Claim
48 words
The method according to Claim 12 wherein the thermoplastic polymer of the first pipe liner is a homopolymer of ethylene or a copolymer of ethylene and at least one alpha-olefin of 4 to 10 carbon atoms and the thermoplastic polymer of the second pipe liner is nylon 6,6.
Claim 18
Dependent Claim
14 words
A tubular structure when lined by the method of any of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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