Heat exchange surface with porous coating and subsurface cavities
First Claim
1. A heat exchange surface comprising means for vaporizing a liquid, said means including continuous subsurface cavities formed in a metallic surface, said cavities being generally abridged where they are open onto the exterior of the metallic surface, by a porous open-celled coating deposited thereon, except at random points at which the cavities are directly open to the liquid said porous coating providing nucleate boiling cavities by its open-cell structure and its random open points in combination with the subsurface cavities, and thereby adapted to provide improved efficiency in boiling the liquid which is in fluid communication with the subsurface cavities.
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Accused Products
Abstract
A heat exchange surface having nucleate boiling cavities defined by subsurface cavities in combination with a thin porous coating. A preferred embodiment of the heat exchange surface includes a plurality of helical fins formed on the outer surface of a metallic tube, the tips of which are deformed by rolling to define gaps opening into fin cavities between adjacent fins. A porous open-celled coating flame-sprayed on the deformed portion of the fins substantially bridges these gaps, except at random open points caused by the inherent porosity of the coating. These openings in the porous coating in combination with the fin cavities provide nucleate boiling sites which promote efficient heat transfer for boiling a liquid.
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Citations
10 Claims
- 1. A heat exchange surface comprising means for vaporizing a liquid, said means including continuous subsurface cavities formed in a metallic surface, said cavities being generally abridged where they are open onto the exterior of the metallic surface, by a porous open-celled coating deposited thereon, except at random points at which the cavities are directly open to the liquid said porous coating providing nucleate boiling cavities by its open-cell structure and its random open points in combination with the subsurface cavities, and thereby adapted to provide improved efficiency in boiling the liquid which is in fluid communication with the subsurface cavities.
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2. A heat exchange surface comprising:
- a metallic surface having a plurality of generally parallel fins formed thereon, the tips of said fins being deformed to generally define a gap between adjacent fins opening into a fin cavity at the root portions thereof;
a porous, open-celled coating deposited on the deformed portion of the fins, substantially bridging the gap between adjacent fins except at random open points caused by the inherent porosity of the coating, said porous coating in combination with the fin cavities, providing nucleate boiling cavities, and thereby adapted to provide improved efficiency in boiling a liquid. - View Dependent Claims (3, 4, 5, 6, 7, 10)
- a metallic surface having a plurality of generally parallel fins formed thereon, the tips of said fins being deformed to generally define a gap between adjacent fins opening into a fin cavity at the root portions thereof;
Specification