METHOD FOR INDUCTIVELY HEATING A SUBSTRATE AND A COATING ON SAID SUBSTRATE

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 wherein a inner heat insulation material is interposed between the susceptor element and the coating. 3. Method as claimed in any one of the preceding claims wherein the susceptor is perforate and foraminous, and preferably provides an open circuit. 4. Method of repairing an opening in a coating on a substrate comprising applying a patch on the opening in the coating wherein said coating is preheated employing a heating method as claimed in any one of claims 1 to 3 to at least an activation temperature for said patch or for a coating on said patch. 5. Method as claimed in claim 4 wherein the substrate is a tubular article and the susceptor element is curved to conform to a surface curvature of the article. 6. Method of applying a coating or covering to a weld joint between tubular substrates having mainline coatings comprising heating said substrates and coatings employing a heating method as claimed in any one of claims 1 to 3 before applying said coating or covering. 7. Method as claimed in claim 6 wherein said covering comprises a heat shrink sleeve and said heating method comprises heating said mainline coatings adjacent the weld joint, and wherein said susceptor element comprises a pair of band form elements applied around the girth of the mainline coatings of the tubular article adjacent the weld joint. 8. Method as claimed in claim 7 including heating the coatings and the articles adjacent the weld joint to at least an activation temperature for the sleeve or for a coating on the sleeve. 9. Method as claimed in any one of the preceding claims wherein the coating comprises polyolefin. 10. Method as claimed in claim 9 wherein the polyolefin is polypropylene. Предложен способ нагрева подложки (11, 12) и покрытия (14, 16) на этой подложке (11, 12). На покрытие (14, 16) накладывают токоприемный элемент (22) и индукционно возбуждают этот элемент (22) и подложку (11, 12) для нагревания подложки (11, 12) и покрытия (14, 16).