High frequency induction fusing
First Claim
1. A method of fusing a self-fusing alloy thermal spray coating or a vitreous ceramic coating on a waterwall panel having a plurality of tubes interconnected by a plurality of membranes, using a movable induction coil assembly comprising the steps of:
- (a) heating at least some portions of at least one membrane and adjacent tubes of the waterwall panel, by induction, to a liquidus temperature of a self-fusing alloy thermal spray coating or a vitreous ceramic coating without significant warpage or adverse change in the microstructure of the material forming the waterwall panel by moving the induction coil assembly across the panel so that the induction coil assembly concentrates induction energy in at least one membrane; and
(b) applying a self-fusing alloy thermal spray coating or a vitreous ceramic coating on the waterwall panel in such a way that the coating is fused at the portions of the panel heated pursuant to step (a).
2 Assignments
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Accused Products
Abstract
A self-fusing alloy thermal spray coating or a vitreous ceramic coating is fused to a complicated metal shape or convoluted metal surface, such as a waterwall panel having a plurality of tubes interconnected by a plurality of membranes, without significant warpage or adverse change in the microstructure of the material forming the panel. The coating is first applied to the panel and then is heated to a liquidus temperature (typically between about 1000°-2200° F.), by induction at a frequency of greater than about 25 kHz, so as to effect fusing. An inductive coil assembly for this purpose comprises a copper tubular combined electrical current conductor and conduit for circulating cooling water having a first closed end and a second end connectable to a source of cooling fluid and a source of electricity. At least one, and preferably a plurality, of copper noses extend outwardly from the combined conductor and conduit and both conduct electricity and circulate cooling fluid. The noses extend substantially perpendicularly to the combined conductor and conduit and are configured so as to effect proper induction heating of the panel. A magnetic flux concentrator is preferably provided over at least some of the noses. Preheating noses (e.g. solid copper blocks) may be connected to a leading portion of the combined conductor and conduit.
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Citations
21 Claims
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1. A method of fusing a self-fusing alloy thermal spray coating or a vitreous ceramic coating on a waterwall panel having a plurality of tubes interconnected by a plurality of membranes, using a movable induction coil assembly comprising the steps of:
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(a) heating at least some portions of at least one membrane and adjacent tubes of the waterwall panel, by induction, to a liquidus temperature of a self-fusing alloy thermal spray coating or a vitreous ceramic coating without significant warpage or adverse change in the microstructure of the material forming the waterwall panel by moving the induction coil assembly across the panel so that the induction coil assembly concentrates induction energy in at least one membrane; and (b) applying a self-fusing alloy thermal spray coating or a vitreous ceramic coating on the waterwall panel in such a way that the coating is fused at the portions of the panel heated pursuant to step (a). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of fusing a self-fusing alloy thermal spray coating or a vitreous ceramic coating on a complicated metal shape or convoluted metal surface having at least two differently configured portions, using a movable induction coil assembly, comprising the steps of:
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(a) applying a self-fusing alloy thermal spray coating or a vitreous ceramic coating on the complicated metal shape or convoluted metal surface so that the coating is fused at a subsequently heated portion thereof; and
then(b) inductive heating at least a portion of the complicated metal shape or convoluted metal surface by induction at a frequency of greater than about 25 kHz to at least the liquidus temperature of the coating by moving the induction coil assembly across the complicated metal shape or convoluted metal surface so that the induction coil assembly heats at least two differently configured portions of the complicated metal shape or convoluted metal surface. - View Dependent Claims (18, 19, 20)
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21. A method of fusing a self-fusing alloy thermal spray coating or a vitreous ceramic coating on a complicated metal shape or convoluted metal surface comprising the steps of:
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(a) applying a self-fusing alloy thermal spray coating or a vitreous ceramic coating on the complicated metal shape or convoluted metal surface so that the coating is fused at a subsequently heated portion thereof; and
then(b) inductive heating at least a portion of the complicated metal shape or convoluted metal surface by induction at a frequency of greater than about 25 kHz to at least the liquidus temperature of the coating; and wherein step (b) is practiced by (i) first passing a preheater with at least one copper nose and without a flux concentrator so that it substantially conforms to the convoluted metal surface or complicated metal shape, and (ii) then passing over the surface or shape a fusion coil assembly having at least one copper nose with a magnetic flux concentrator substantially conforming to the convoluted metal surface or complicated metal shape so as to effect fusing; and
wherein substeps (i) and (ii) are practiced using a unitary structure.
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Specification