Ultra-thin flexible expanded graphite resistance heater

Abstract

An ultra-thin flexible expanded graphite heating high resistance element is produced by a method including the steps of providing a flexible expanded graphite sheet having a surface adhered to a substrate; pulling apart the sheet and the substrate with a force sufficient to separate the adhered flexible expanded graphite sheet into a removed layer and a remainder layer adhered to the substrate; and optionally repeating the foregoing steps until the remainder layer has a thickness of about 0.01 mils to about 2 mils. A resistance heater for high voltage applications is also provided.

We claim:  
     
         1 . An ultra-thin flexible expanded graphite heating element, produced by a method comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a surface adhered to a substrate;    (b) pulling apart the sheet and the substrate with a force sufficient to separate the adhered flexible expanded graphite sheet into a removed layer and a remainder layer adhered to the substrate; and    (c) optionally repeating steps (a) and (b) until the remainder layer has a thickness of about 0.01 mils to about 2 mils.    
     
     
         2 . The heating element of  claim 1 , wherein the thickness of the remainder layer is substantially uniform.  
     
     
         3 . The heating element of  claim 1 , wherein the thickness of the remainder layer is non-uniform.  
     
     
         4 . The heating element of  claim 1 , wherein the substrate is electrically insulating.  
     
     
         5 . An ultra-thin flexible expanded graphite heating element, produced by a method comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a top surface, and a bottom surface adhered to a first substrate;    (b) adhering a second substrate to the top surface; and    (c) separating the first and second substrates with a force sufficient to separate the flexible expanded graphite sheet into a first remainder layer adhered to the first substrate and a second remainder layer adhered to the second substrate; and    (d) optionally repeating steps (a), (b) and (c) until at least one of the remainder layers has a thickness of about 0.01 mils to about 2 mils.    
     
     
         6 . The heating element of  claim 5 , wherein the thicknesses of the remainder layers are independent and are substantially uniform.  
     
     
         7 . The heating element of  claim 5 , wherein the thicknesses of the remainder layers are independent and non-uniform.  
     
     
         8 . The heating element of  claim 5 , wherein at least one of the substrates is electrically insulating.  
     
     
         9 . An ultra-thin flexible expanded graphite heating element having a non-uniform thickness, produced by a method comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a top surface, and a bottom surface adhered to a first substrate;    (b) non-uniformly adhering a second substrate to the top surface; and    (c) separating the first and second substrates with a force sufficient to separate the flexible expanded graphite sheet into a first remainder layer adhered to the first substrate and a second remainder layer adhered to the second substrate; and    (d) optionally repeating steps (a), (b) and (c) until at least a portion of one of the remainder layers has thickness of about 0.01 mils to about 2 mils.    
     
     
         10 . The heating element of  claim 9 , wherein the thicknesses of the remainder layers are independently non-uniform.  
     
     
         11 . The heating element of  claim 9 , wherein at least one of the substrates is electrically insulating.  
     
     
         12 . An ultra-thin flexible expanded graphite sheet having a thickness of about 0.01 mils to about 2 mils.  
     
     
         13 . The sheet of  claim 12 , wherein the thickness is about 0.01 mils to about 1.5 mils.  
     
     
         14 . The sheet of  claim 12 , wherein the thickness is about 0.01 mils to about 1 mils.  
     
     
         15 . The sheet of  claim 12 , wherein the thickness is about 0.01 mils to about 0.4 mils.  
     
     
         16 . The sheet of  claim 12 , wherein the thickness is about 0.01 mils to about 0.1 mils.  
     
     
         17 . A resistance heater for high voltage applications, comprising: 
 (a) an electrically insulating substrate;    (b) a flexible expanded graphite sheet having a thickness of about 0.01 mils to about 2 mils;    (c) a power source; and    (d) a connector for supplying power from the power source to the flexible expanded graphite sheet.    
     
     
         18 . A method for making an ultra-thin flexible expanded graphite heating element, comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a surface adhered to a substrate;    (b) pulling apart the sheet and the substrate with a force sufficient to separate the adhered flexible expanded graphite sheet into a removed layer and a remainder layer adhered to the substrate; and    (c) optionally repeating steps (a) and (b) until the remainder layer has a thickness of about 0.01 mils to about 2 mils.    
     
     
         19 . The method of  claim 13 , wherein the thickness of the remainder layer is substantially uniform.  
     
     
         20 . The method of  claim 13 , wherein the thickness of the remainder layer is non-uniform.  
     
     
         21 . The method of  claim 13 , wherein the substrate is electrically insulating.  
     
     
         22 . A method for making an ultra-thin flexible expanded graphite heating element, comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a top surface, and a bottom surface adhered to a first substrate;    (b) adhering a second substrate to the top surface; and    (c) separating the first and second substrates with a force sufficient to separate the flexible expanded graphite sheet into a first remainder layer adhered to the first substrate and a second remainder layer adhered to the second substrate; and    (d) optionally repeating steps (a), (b) and (c) until at least one of the remainder layers has a thickness of about 0.01 mils to about 2 mils.    
     
     
         23 . The method of  claim 17 , wherein the thicknesses of the remainder layers are independent and are substantially uniform.  
     
     
         24 . The method of  claim 17 , wherein the thicknesses of the remainder layers are independent and non-uniform.  
     
     
         25 . The method of  claim 17 , wherein at least one of the substrates is electrically insulating.  
     
     
         26 . A method for making an ultra-thin flexible expanded graphite heating element having a non-uniform thickness, comprising the steps of: 
 (a) providing a flexible expanded graphite sheet having a top surface, and a bottom surface adhered to a first substrate;    (b) non-uniformly adhering a second substrate to the top surface; and    (c) separating the first and second substrates with a force sufficient to separate the flexible expanded graphite sheet into a first remainder layer adhered to the first substrate and a second remainder layer adhered to the second substrate; and    (d) optionally repeating steps (a), (b) and (c) until at least a portion of one of the remainder layers has thickness of about 0.01 mils to about 2 mils.    
     
     
         27 . The method of  claim 21 , wherein the thicknesses of the remainder layers are independently non-uniform.  
     
     
         28 . The method of  claim 21 , wherein at least one of the substrates is electrically insulating.