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US 4,402,789 AGranted
Method of coating an insulated electrical conductor
AssigneeNorthern Telecom Limited
InventorGavriel L. Vexler
Life of this patent
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Abstract
Provision of a protective cover for a fibrous layer of insulation on a conductor by forming an inner layer of the protection cover by depositing a polymeric based composition without creating a crushing effect, and then, in tandem, hardening the inner layer and applying a second coat by extrusion. The inner layer absorbs the crushing forces of extrusion to protect the fibrous layer during addition of the second layer. The inner layer is preferably formed by electrostatic deposition coating and prevents pinhole formation in the second layer.
Claims3
A method of producing an insulated electrical conductor comprising:
- providing a layer of dried pulp insulation upon a conductor by applying wet pulp and drying it to expand it before adding any further layers of any material;
- and
- forming a surrounding protection for the insulation layer by:
- (i) providing a first or inner protective layer for the dried pulp by depositing a polymeric based composition upon the pulp by a process which avoids the use of crushing forces upon the pulp;
- (ii) heating the first or inner layer to cause it to harden and, then directly in tandem with the hardening treatment and with the inner layer retained in a heated state;
- (iii) applying a second or outer layer of a polymeric composition to the inner layer by extruding it onto the first layer, the hardened inner layer serving to absorb and protect the, pulp from crushing forces created by extrusion.
3 more elements
Dependencies are inferred from the claim text.