TWO STEP POROUS BOILING SURFACE FORMATION

• US 3,753,757 A
• Filed: 05/15/1970
• Issued: 08/21/1973
• Est. Priority Date: 05/15/1970
• Status: Expired due to Term

• Current Assignee: UOP Des Plaines IL A NY General Partnership
• Original Assignee: Arthur Rodgers, Robert J. Weiner
• Inventors: Rodgers, Arthur, Weiner, Robert J.
• Primary Examiner(s): Katz, Murray
• Assistant Examiner(s): Sofocleous, M.
• Application Number:
  US05/037,649
• Time in Patent Office: 1,194 Days
• Field of Search: 117/46C,46A,22,31,33,131
• US Class Current: 427/183
• CPC Class Codes: B22F 7/002 of porous nature
• CPC Class Codes: F28F 13/187 especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites

Abstract

A method of coating metal substrates with a porous metal layer, comprising the steps of: A. PROVIDING A METAL SUBSTRATE TO BE POROUS METAL COATED; B. APPLYING A LIQUID BINDER SOLUTION CONSISTING ESSENTIALLY OF AT LEAST ONE HIGH VOLATILITY SOLVENT COMPONENT AND AT LEAST ONE LOW VOLATILITY COMPONENT IN A LAYER FROM 0.002 TO 0.040 INCH THICK ONTO SAID METAL SUBSTRATE; C. APPLYING A 0.005 TO 0.050 INCH THICK LAYER OF METAL POWDER 30-500 MESH ONTO THE BINDER LAYER SO THAT THE BINDER LAYER WETS THE METAL POWDER COATING AND IS SATURATED THEREBY AND RETAINS SUBSTANTIALLY ALL OF SAID POWDER AGAINST SAID METAL SUBSTRATE; D. EVAPORATING SUBSTANTIALLY ALL OF THE HIGH VOLATILITY COMPONENT OF SAID LIQUID BINDER SOLUTION AT ABOUT AMBIENT TEMPERATURE; E. HEATING THE METAL POWDER COATED METAL SUBSTRATE OF (D) TO TEMPERATURE SUFFICIENT TO EVAPORATE SUBSTANTIALLY ALL OF THE BINDER LOW VOLATILITY COMPONENT; F. FURTHER HEATING THE METAL POWDER COATED METAL SUBSTRATE TO TEMPERATURE SUFFICIENT TO BOND THE METAL POWDER TO ITSELF AND TO THE METAL SUBSTRATE SO AS TO FORM A POROUS METAL LAYER HAVING INTERCONNECTED SURFACE AND SUBSURFACE CAVITIES; AND G. COOLING THE POROUS METAL LAYER BONDED METAL SUBSTRATE.

Claims

2. A method as described in claim 1 wherein the liquid binder solution consists of by weight 15-50 percent isobutylene polymer, 50-85 percent kerosene.

3. A method as described in claim 1 wherein the liquid binder solution consists of by weight 15-25 percent isobutylene polymer, 40-60 percent toluene, and 25-40 percent kerosene.

4. A method as described in claim 1 wherein one low volatility and two high volatility components comprise the liquid binder solution.

5. A method as described in claim 1 wherein the metal powder layer is accomplished in two separate metal powder applications.

6. A method as described in claim 1 for coating corrugated metal tubes wherein the metal powder application is accomplished by electrostatic spraying.

7. A method according to claim 1 wherein said metal substrate to be porous metal coated is horizontal, the liquid binder solution consists of 16 percent by weight isobutylene polymer and 84 percent by weight kerosene and is applied in a thickness of 0.015 inch, and 100-200 mesh metal powder is applied onto the binder layer in quantity such that the final thickness of powder is 0.020 inch.

8. A method according to claim 1 wherein said metal substrate to be porous metal coated is horizontal, the liquid binder solution consists of 15 percent by weight isobutylene polymer and 85 percent by weight kerosene and is applied in a thickness of 0.010 inch, and 200-400 mesh metal powder is applied onto the binder layer in quantity such that the final thickness of powder is 0.015 inch.

9. A method according to claim 1 wherein said metal substrate to be porous metal coated is an internal tube surface, the liquid binder solution consists of 36 percent by weight isobutylene polymer and 64 percent by weight toluene and is applied in a thickness of 0.017 inch, and 100-270 mesh metal powder is applied onto the binder layer in quantity such that the final thickness of powder is 0.023 inch.

10. A method according to claim 1 wherein said metal substrate to be porous metal coated is an internal tube surface, the liquid binder solution consists of 34 percent by weight isobutylene polymer and 66 percent by weight toluene and is applied in a thickness of 0.012 inch, and 270-400 mesh metal powder is applied onto the binder layer in quanTity such that the final thickness of powder is 0.019 inch.

11. A method according to claim 1 wherein said metal substrate is vertical, the liquid binder solution consists of 18 percent by weight isobutylene polymer and 82 percent by weight kerosene and is applied in a thickness of 0.013 inch, and 100-270 mesh metal powder is applied onto the binder layer in quantity such that the final thickness of powder is 0.020 inch.

12. A method according to claim 1 wherein said metal substrate is vertical, the liquid binder solution consists of 17 percent by weight isobutylene polymer and 83 percent by weight kerosene and is applied in a thickness of 0.008 inch, and 270-400 mesh metal powder is applied onto the binder layer in quantity such that the final thickness of powder is 0.015 inch.