Method for forming an electrical heating element by flame spraying a metal/metallic oxide matrix
OwnerJeffery Boardmaninventor
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Abstract
A method for forming an electrical heating element by flame spraying a metal/metallic oxide matrix, wherein a flame sprayed metal/metallic oxide matrix is deposited onto an insulating or conductive substrate such as to have a higher resistance than is required for a designed use, and an intermittently pulsed high voltage DC supply is applied across the matrix such as to produce continuous electrically conductive paths through the matrix which permanently increase the overall conduction and simultaneously reduce the overall resistance of the metal/metallic matrix to achieve a desired resistance value.
Claims10
A method for forming an electrical heating element by flame spraying a metal/metallic oxide matrix, wherein a flame sprayed metal/metallic oxide matrix is deposited onto an insulating or conductive substrate such as to have a higher resistance than is required for a designed use, and an intermittently pulsed high voltage DC supply is applied across the matrix such as to produce continuous electrically conductive paths through the matrix which permanently increase the overall conduction and simultaneously reduce the overall resistance of the metal/metallic matrix to achieve a desired resistance value.
An apparatus for manufacturing an electrical heating element, comprising:
- (a) means for depositing a metal/metallic oxide matrix onto an insulating or conductive substrate by flame spraying, such that the matrix has initially a higher resistance than is required for a designed use of the heating element;
- (b) means for applying a first, continuous DC voltage to the metal/metallic oxide matrix in the direction in which the particular configuration of metal/metallic oxide matrix is intended to operate as an electrical resistance heating element;
- (c) means for determining the resistance of the metal/metallic matrix from OHM's Law calculations based on the values of the continuously applied DC voltage and resulting current flow;
- (d) means for applying a second DC voltage source to the flame sprayed metal/metallic oxide matrix in the same direction as the continuously applied first DC voltage, and in a series of high frequency intermittent pulses to cause the overall conductivity of the metal/metallic oxide matrix to increase, with corresponding decrease in overall resistance;
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- (e) means for monitoring the increase in the current flowing through the metal/metallic oxide matrix by virtue of the continuously applied first DC voltage until a calculation using OHM' s Law demonstrates that the overall resistance of the flame sprayed metal/metallic oxide matrix has been reduced to a value required for that particular design and configuration of flame sprayed deposited metal/metallic oxide matrix.
Dependencies are inferred from the claim text.