Heat transfer surface and method for producing such surface

• US 4,246,057 A
• Filed: 12/27/1977
• Issued: 01/20/1981
• Est. Priority Date: 02/16/1977
• Status: Expired due to Term

• Current Assignee: Wolverine Tube Incorporated
• Original Assignee: UOP Llc (Honeywell International Inc.)
• Inventors: Bradley, Steven A., Shum, Ming S., Janowski, Kenneth R.
• Primary Examiner(s): Goolkasian, John T.
• Assistant Examiner(s): Dawson, Robert A.
• Application Number:
  US05/864,901
• Time in Patent Office: 1,120 Days
• Field of Search: 156/82, 156/150, 156/187, 156/155, 165/133, 165/180, 165/181, 165/183, 165/184, 204/11, 204/20, 204/37 R, 427/250, 427/296, 427/306, 427/404, 427/224, 427/225, 427/227, 428/310, 428/311, 428/313, 29/157.4, 29/459, 138/144, 138/145, 138/146
• US Class Current: 156/150
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/1137 by coating porous removable preforms
• CPC Class Codes: B22F 7/006 the porous part being obtained by foaming
• CPC Class Codes: B23P 15/26 heat exchangers or the like making heat exchangers by methods covered by other subclasses B21D53/02
• CPC Class Codes: B29C 63/10 around tubular articles
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2705/10 Copper
• CPC Class Codes: B29L 2009/003 comprising a metal layer
• CPC Class Codes: C25D 7/00 Electroplating characterised by the article coated
• CPC Class Codes: F16L 9/14 Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups F16L9/16 - F16L9/22 take precedence
• CPC Class Codes: F28F 13/187 especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites
• CPC Class Codes: Y10S 138/09 Cellular
• CPC Class Codes: Y10T 29/49377 Tube with heat transfer means
• CPC Class Codes: Y10T 29/49886 to roughen surface
• CPC Class Codes: Y10T 428/24999 Inorganic

Abstract

The invention relates to improving the heat transfer properties in boiling liquids of tubes and other surfaces by applying a very porous reticulated organic foam layer in contact with the tube surface, and then plating a thin metal coating on the foam substrate. Preferably, the tube is copper and the plating consists of a first electrolessly applied layer of copper and a second electroplated layer. The foam is preferably in the form of a thin tape which is spirally wound about the tube. Pyrolization of the foam after plating improves the heat transfer performance of the tube.

Claims

1. A method of providing a metal heat transfer tube with a porous nucleate boiling surface comprising the steps of applying a layer of reticulated open cell organic foam material to the external surface of the metal tube and then plating the exposed surfaces of the reticulated foam material with a metal so as to form a reticulated metal surface which overlies the surface of the metal tube and is firmly adhered thereto, said tube being heated after it is plated to pyrolyze the organic foam material and cause the reticulated metal surface which had been plated around the organic foam material to become a hollow metal skeleton capable of trapping vapor when the tube is placed in a liquid boiling medium and releasing some of said vapor through a multiplicity of openings or pores in said skeleton which comprise vapor phase nucleation sites.

2. The method of claim 1 wherein said plating step includes an initial electroless deposit of metal followed by an electro-deposit deposit of metal.

3. The method of claim 1 wherein said layer of foam material is applied by spirally wrapping a strip of said foam material about said tube.

4. The method of claim 1 wherein said plating is made sufficiently thin that portions of it will be fractured by gases developed during pyrolyzation to produce pore openings therein.

5. The method of claim 1 wherein said heating takes place at a temperature of less than about 900°

F.

6. The method of claim 1 wherein said foam material has a pore size of about 100 pores per inch.