Method for inductively heating a substrate and a coating on a substrate

Abstract

A method of heating a substrate and a coating on the substrate. A susceptor element is applied on the coating and the element and the substrate are inductively energized to cause the substrate and the coating to be heated.

1 . Method for heating a substrate and a coating on said substrate comprising applying on the coating a susceptor element, wherein said susceptor and substrate are inductively heatable, and inductively energizing the element and substrate to cause said substrate and coating to be heated.  
     
     
         2 . Method as claimed in  claim 1  wherein a heat insulation material is provided on an outer side of the susceptor element.  
     
     
         3 . Method as claimed in  claim 1  wherein a inner heat insulation material is interposed between the susceptor element and the coating.  
     
     
         4 . Method as claimed in  claim 5  wherein the inner insulation material includes a release layer.  
     
     
         5 . Method as claimed in  claim 1  wherein the susceptor is perforate or foraminous.  
     
     
         6 . Method as claimed in  claim 1  wherein the susceptor element provides an open circuit.  
     
     
         7 . Method as claimed in  claim 1  wherein the susceptor element provides a closed circuit.  
     
     
         8 . Method of repairing an opening in a coating on a substrate comprising heating said coating employing a heating method as claimed in any of  claim 1  to heat the coating before applying a patch.  
     
     
         9 . Method as claimed in  claim 8  comprising heating said coating to at least an activation temperature for said patch or for a coating on said patch.  
     
     
         10 . Method as claimed in  claim 8  wherein the substrate is a tubular article and the susceptor element is curved to conform to a surface curvature of the article.  
     
     
         11 . Method of applying a coating or covering to a weld joint between tubular substrates each having a mainline coating, comprising heating said substrates and coatings employing a heating method as claimed in  claim 1  before applying said coating or covering.  
     
     
         12 . Method as claimed in  claim 11  wherein said covering comprises a heat shrink sleeve and said heating method comprises heating each mainline coating adjacent the weld joint, and wherein each susceptor element comprises a band form element applied around the girth of the mainline coating of the tubular substrate adjacent the weld joint.  
     
     
         13 . Method as claimed in  claim 12  including heating each coating and substrate adjacent the weld joint to at least an activation temperature for the sleeve or for a coating on the sleeve.  
     
     
         14 . Method as claimed in  claim 1  wherein the coating comprises polyolefin.  
     
     
         15 . Method as claimed in  claim 14  wherein the polyolefin is polypropylene.