US 5,476,562 AGranted

Large diameter electrically fusible pipe methods

AssigneeCentral Plastics Company

InventorJames A. Inhofe, Jr.

Life of this patent

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Abstract

Methods of producing electrically fusable sleeve connectors for connecting large diameter thermoplastic pipe sections and the sleeve connectors produced by such methods are provided. Methods of sealingly connecting adjacent ends of a pair of large diameter thermoplastic pipe sections by electric fusion are also provided. The methods of producing electrically fusable thermoplastic sleeve connectors broadly include the steps of winding a tape of molten thermoplastic material onto a large diameter core drum whereby adjacent windings are fused and upon being cooled a solid sleeve is formed, embedding an electric resistance heating wire in a surface of the sleeve while the thermoplastic material is still in the molten state and removing the sleeve after cooling with electric resistance heating wire embedded therein from the core drum.

Claims5

Dependent claims

A method of producing an electrically fusible solid thermoplastic sleeve connector for longitudinally connecting large diameter thermoplastic pipe sections comprising the steps of:

(a) extruding a tape of molten thermoplastic material;
(b) winding said tape of molten thermoplastic material onto a large diameter core drum having a winding surface of about 24 inches in diameter or greater to form a sleeve whereby adjacent windings in said sleeve are fused and upon being cooled a solid large diameter pipe connector is formed, said core drum having an inflated bladder attached thereto which forms said winding surface thereof;
(c) embedding at least one electric resistance heating wire within and adjacent a surface of said sleeve while said thermoplastic material is in the molten state;
(d) allowing said thermoplastic material to cool whereby a solid large diameter sleeve pipe connector is formed;
and
(e) removing said cooled solid large diameter sleeve pipe connector with said electrical resistance heating wire embedded therein from said core drum.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/348,761Filed 2 Dec 1994 · continuation
Priority: 1 May 1989
Granted: 19 Dec 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification25 codes

F16L 47/03
Welded joints; Adhesive joints: welded joints with an electrical resistance incorporated in the joint
B29C 33/505
Elastic or flexible: cores or mandrels, e.g. inflatable
B29C 48/09
Characterised by the shape of the extruded material at extrusion: articles with cross-sections having partially or fully enclosed cavities, e.g.…
B29C 65/342
Characterised by the type of heated elements which remain in the joint: comprising at least a single wire, e.g. in the form of a winding

Family

Serial345,455Parent of this division · filed 1 May 1989
Serial594,047Parent of this continuation · filed 1 Nov 1990
Serial866,297Parent of this continuation · filed 13 Apr 1992
Serial4,789Parent of this continuation · filed 14 Jan 1993
Serial96,453Parent of this continuation · filed 26 Jul 1993
US 5,252,157 AParent of this continuation
US 5,476,562 AThis patent

From the US filing history. Foreign family members aren’t listed.