Coated overhead conductor

Abstract

The present invention relates to a surface modified overhead conductor with a coating that allows the conductor to operate at lower temperatures. The coating contains about 5% to about 30% of an inorganic adhesive, about 45% to about 92% of a filler, about 2% to about 20% of one or more emissivity agents, and about 1% to about 5% of a stabilizer.

What is claimed is: 
     
         1 . An overhead cable comprising a bare conductor coated with a coating layer containing about 5% to about 30% of an inorganic adhesive, about 45% to about 92% of a filler, and about 2% to about 20% of one or more emissivity agents. 
     
     
         2 . The overhead cable of  claim 1 , wherein the inorganic adhesive is selected from the group consisting of sodium silicate, potassium silicate, lithium silicate, calcium silicate, and magnesium silicate. 
     
     
         3 . The overhead cable of  claim 1 , wherein the filler is selected from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, and boron oxide. 
     
     
         4 . The overhead cable of  claim 1 , wherein the emissivity agent is selected from the group consisting of carbon tetraboride (boron carbide), boron nitride, silicon tetraboride, silicon carbide, molybdenum disilicide, zirconium diboride, cupric chromite, iron oxide, magnesium oxide, manganese oxide, copper chromium oxide, and chromium oxide. 
     
     
         5 . The overhead cable of  claim 1 , further comprising about 1% to about 5% of a stabilizer. 
     
     
         6 . The overhead cable of  claim 5 , wherein the stabilizer is selected from the group consisting of bentonite, kaolin, magnesium alumina silica clay, tabular alumina, and stabilized zirconium oxide. 
     
     
         7 . The overhead cable of  claim 1 , wherein the coating layer contains about 13-15% sodium silicate, about 68-69% silicon dioxide powder, about 14-16% boron carbide, and about 1-1.5% bentonite powder. 
     
     
         8 . The overhead cable of  claim 1 , wherein the coating layer contains about 13-15% sodium silicate, about 68-69% silicon dioxide powder, about 13-15% boron carbide, 1-2% boron nitride, and about 1-1.5% bentonite powder. 
     
     
         9 . The overhead cable of  claim 1 , wherein the coating thickness is less than about 200 microns. 
     
     
         10 . The overhead cable of  claim 1 , wherein the bare conductor comprises one or more conductive wires of copper, or a copper alloy, or an aluminum or aluminum alloy, including aluminum types 1350 alloy aluminum, 6000-series alloy aluminum, or aluminum-zirconium alloy or any other conductive metal. 
     
     
         11 . A method for making a surface modified overhead conductor comprising the steps of
 a. preparing a bare conductor;   b. applying a liquid coating mixture on the surface of a conductor to form a coated conductor, wherein the liquid coating comprises 45-55% solid content and the solid content contains about 5% to about 30% of an inorganic adhesive, about 45% to about 92% of a filler, and about 2% to about 20% of one or more emissivity agents; and   c. drying the coated conductor.   
     
     
         12 . The method of  claim 11 , the liquid coating comprises about 50% solid content and the solid content contains about 13-15% sodium silicate, about 68-69% silicon dioxide powder, about 14-16% boron carbide, and about 1-1.5% bentonite powder. 
     
     
         13 . The method of  claim 11 , the liquid coating comprises about 50% solid content and the solid content contains about 13-15% sodium silicate, about 68-69% silicon dioxide powder, about 13-15% boron carbide, 1-2% boron nitride, and about 1-1.5% bentonite powder. 
     
     
         14 . The method of  claim 11 , wherein step a comprises the steps of sand blasting the conductor, and passing the sand blasted conductor through an air wipe. 
     
     
         15 . The method of  claim 14 , wherein after the air wipe, the number of particles, that are greater than 10 microns in size, on the surface of the conductor are lower than 1,000 per square feet of the conductor surface. 
     
     
         16 . The method of  claim 14 , wherein step a further comprising the step of heating the conductor after the air wipe. 
     
     
         17 . The method of  claim 16 , wherein the heating is by direct flame exposure. 
     
     
         18 . The method of  claim 11 , wherein step b comprises passing the conductor through a flooded die and then through an air wipe. 
     
     
         19 . The method of  claim 18 , wherein the flooded die comprises an annular shaped portion with a center opening through which the bare conductor passes. 
     
     
         20 . The method of  claim 18 , wherein the flooded die further comprises a tube for carrying the liquid coating mixture to the die. 
     
     
         21 . The method of  claim 18 , wherein the flooded die comprises opening ports through which the liquid coating mixture is deposited on to the conductor. 
     
     
         22 . The method of  claim 11 , wherein step c comprises heating the conductor. 
     
     
         23 . The method of  claim 22 , wherein the heating is by direct flame exposure. 
     
     
         24 . The method of  claim 11 , wherein the solid content further contains about 1% to about 5% of a stabilizer.