Resistive heaters and uses thereof

Abstract

The present invention features a metallic resistive heater and uses thereof. The resistive heater includes a metallic component that is electrically conductive (i.e., has low resistivity) and an oxide, nitride, carbide, and/or boride derivative of the metallic component that is electrically insulating (i.e., has high resistivity). The resistivity is controlled in part by controlling the amount of oxide, nitride, carbide, and boride formation during the deposition of the metallic component and the derivative.

47 . A cylindrical roller comprising an outer surface, an inner surface surrounding a hollow core, and a resistive heater comprising a resistive layer coupled to a power source, said resistive layer comprising a metallic component and one or more oxide, nitride, carbide, and/or boride derivatives of said metallic component, wherein said resistive layer has a resistivity of 0.0001 to 1.0 Ωcm, and wherein application of current from said power supply to said resistive layer results in production of heat by said resistive layer, wherein said resistive heater is disposed on said outer surface or said inner surface.  
   
   
       48 - 50 . (canceled)  
   
   
       51 . A roller, comprising: 
 a cylinder having an outer surface and an inner surface surrounding a hollow core; and    a resistive heater coating comprising a resistive layer, where the resistive layer is coupled to a power source, the resistive layer comprising a metallic component and one or more oxide, nitride, carbide, and/or boride derivatives of the metallic component, wherein the resistive layer has a resistivity of 0.0001 to 1.0 Ohm-cm, wherein application of current from the power supply to the resistive layer results in production of heat by the resistive layer, and wherein the resistive heater coating is disposed on the cylinder.    
   
   
       52 . The roller of  claim 51 , wherein the resistive heater coating is disposed on the outer surface of the cylinder.  
   
   
       53 . The roller of  claim 51 , wherein the resistive heater coating is disposed on the inner surface of the cylinder.  
   
   
       54 . The roller of  claim 51 , further comprising an electrically insulating layer located substantially between the cylinder and the resistive layer.  
   
   
       55 . The roller of  claim 51 , further comprising an anticorrosive coating applied to the cylinder.  
   
   
       56 . The roller of  claim 51 , further comprising a metal casing affixed to the cylinder.  
   
   
       57 . The roller of  claim 51 , wherein the resistive layer is formed by a reaction of at least a portion of the solid metallic component and a reactant gas by melting at least a portion of the solid metallic component to form a stream of molten droplets, and providing controlled introduction of the reactant gas to the molten droplets, thereby combining the molten droplets and the reactant gas, resulting in a free metal and reaction product.  
   
   
       58 . A method of making a roller, the method comprising the steps of: selecting a solid metallic component and at least one reactant gas; 
 selecting a proportion of the solid metallic component and the at least one reactant gas to achieve a desired resistivity of a resistive layer;    promoting reaction of at least a portion of the solid metallic component and the reactant gas by melting at least a portion of a solid metallic component resulting in a stream of molten droplets, and providing controlled introduction of the reactant gas to the molten droplets, thereby combining the molten droplets and the reactant gas, resulting in a free metal and reaction product;    depositing the combined free metal and reaction product on a cylinder having an outside surface and an inside surface, to form the resistive layer having the desired resistivity; and    providing power to the resistive layer.    
   
   
       59 . The method of  claim 58 , wherein said reaction product is one or more oxide, nitride, carbide, and/or boride derivatives of said metallic component.  
   
   
       60 . The method of  claim 58 , further comprising the step of applying an anticorrosive coating to the cylinder.  
   
   
       61 . The method of  claim 58 , wherein the step of depositing the combined free metal and reaction product on the cylinder further comprises depositing the combined free metal and reaction product using a high velocity oxy-fuel wire spray system, titanium wire, and nitrogen gas.  
   
   
       62 . The method of  claim 58 , further comprising the step of thermally spraying a layer of aluminum oxide to the cylinder.  
   
   
       63 . The method of  claim 58 , further comprising the step of applying at least one layer of a high-temperature sealant to the cylinder.  
   
   
       64 . The method of  claim 63 , further comprising the step of coating the cylinder with a high-temperature silicone.  
   
   
       65 . The method of  claim 58 , further comprising the step of affixing a metal casing to the cylinder.  
   
   
       66 . The method of  claim 58 , further comprising the step of thermally spraying a metallic layer over the outside surface of the cylinder.  
   
   
       67 . The method of  claim 58 , further comprising the step of applying an electrically insulating layer substantially between the cylinder and the resistive layer.  
   
   
       68 . The method of  claim 58 , wherein the step of depositing the combined free metal and reaction product on a cylinder is performed in a manner to provide the cylinder with a pattern of heating zones.