Flame-sprayed ferrous alloy enhanced boiling surface
First Claim
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1. A method of depositing on a metal substrate a porous ferrous alloy boiling surface having macropores therein to enhance boiling which method comprises the steps of:
- (a) aligning an oxy-fuel spray gun in relationship to said substrate such that the centerline distance between the nozzle of said spray gun and said substrate is from about 4 inches (10.2 cm) to about 6 inches (15.2 cm) and said spray gun is inclined so that the angle of flame spraying is from about 30°
to about 50°
;
(b) entraining ferrous alloy powder in an inert gas stream;
(c) injecting said inert gas stream into a reducing oxy-fuel flame which is dispensed from the nozzle of said spray gun; and
(d) providing relative movement between said oxy-fuel flame and said substrate so as to apply at least one layer of ferrous alloy powder onto said substrate.
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Abstract
A porous boiling surface and method of making, which surface comprises a flame-sprayed matrix of ferrous alloy powder on a metal substrate, the matrix being characterized by having irregularly spaced, angled macropores which extend partly through the thickness of the matrix and which improve the boiling perfrmance of the surface.
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Citations
10 Claims
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1. A method of depositing on a metal substrate a porous ferrous alloy boiling surface having macropores therein to enhance boiling which method comprises the steps of:
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(a) aligning an oxy-fuel spray gun in relationship to said substrate such that the centerline distance between the nozzle of said spray gun and said substrate is from about 4 inches (10.2 cm) to about 6 inches (15.2 cm) and said spray gun is inclined so that the angle of flame spraying is from about 30°
to about 50°
;(b) entraining ferrous alloy powder in an inert gas stream; (c) injecting said inert gas stream into a reducing oxy-fuel flame which is dispensed from the nozzle of said spray gun; and (d) providing relative movement between said oxy-fuel flame and said substrate so as to apply at least one layer of ferrous alloy powder onto said substrate. - View Dependent Claims (2, 3, 4)
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- 5. An enhanced boiling surface comprising a metal substrate and a flame-sprayed matrix of ferrous alloy particles thereon, said matrix having nucleate boiling sites therein and further characterized by having randomly disposed, irregularly shaped macropores therein which extend inwardly from the outer surface of the matrix to a depth equal to at least one-third the thickness of the matrix and which macropores have axial centerlines with approximately the same orientation one with the other and which interesect the substrate surface at an acute angle, which macropores enhance boiling by providing improved access of liquid to and vapor from the nucleate boiling sites throughout the matrix, said ferrous alloy particles being flame-sprayed in a gas stream comprising a reducing environment.
Specification