Apparatus for embossing expanded graphite sheet material under reduced pressure

Abstract

A method for embossing expanded graphite sheet material comprises removing at least a portion of the gas from within the material by exposing the material to a pressure less than atmospheric pressure, and then embossing the material. The pressure to which the material is exposed is preferably no greater than about 400 torr. An apparatus for embossing expanded graphite sheet material at a pressure less than atmospheric pressure comprises: an embossing device, a compression device adapted to urge the embossing device against the material, an embossing chamber comprising the at least one embossing device and adapted to receive the material and to be substantially gas-tight at least when the embossing device is urged against the material by the pressing device, and an evacuation device for reducing the pressure within the embossing chamber.

What is claimed is:  
     
         1 . An apparatus for embossing expanded graphite sheet material, said apparatus comprising: 
 (a) a chamber adapted to receive said material and to maintain a reduced pressure less than atmospheric pressure at least when said material is in said chamber;    (b) an evacuation mechanism for reducing the pressure within said embossing chamber; and    (c) at least one roller die associated with said chamber for receiving said material from said chamber.    
     
     
         2 . The apparatus of  claim 1  wherein said chamber comprises at least one resilient member extending from an interior surface of said chamber and adapted to contact said material.  
     
     
         3 . The apparatus of  claim 1  wherein said chamber comprises an upper portion and a lower portion, said upper portion comprising a plurality of resilient sealing members extending downwardly therefrom, and said lower portion comprising a plurality of resilient sealing members extending upwardly therefrom, both sets of said sealing members adapted to contact said material.  
     
     
         4 . The apparatus of  claim 3 , further comprising at least one feed roller for directing said material to said chamber.  
     
     
         5 . The apparatus of  claim 4  wherein said at least one feed roller is a pin roller.  
     
     
         6 . The apparatus of  claim 1  wherein said chamber comprises at least two rollers adapted to contact a major surface of said material, such that a substantially gas-tight seal is formed therebetween.  
     
     
         7 . The apparatus of  claim 6  wherein at least one of said rollers and said at least one roller die are the same.  
     
     
         8 . The apparatus of  claim 6  wherein said at least two rollers comprise at least two pair of opposed rollers, each of said pairs of opposed rollers adapted to contact opposing major surfaces of said material.  
     
     
         9 . The apparatus of  claim 6 , further comprising at least one sealing member associated with said chamber for maintaining a gas-tight seal therein.  
     
     
         10 . The apparatus of  claim 9  wherein said at least one sealing member comprises a sealing member disposed at each end of at least one of said rollers.  
     
     
         11 . The apparatus of  claim 9  wherein said at least one sealing member comprises a resilient member adapted to contact the cylindrical surface of at least one of said rollers, such that a substantially gas-tight seal is formed therebetween.  
     
     
         12 . The apparatus of  claim 9 , further comprising a resilient member adapted to contact the cylindrical surface of at least one of said rollers, such that a substantially gas-tight seal is formed therebetween.  
     
     
         13 . The apparatus of  claim 8  wherein at least one of said rollers is driven.  
     
     
         14 . The apparatus of  claim 8 , further comprising at least one feed roller for directing said material to said chamber.  
     
     
         15 . The apparatus of  claim 14  wherein said at least one feed roller is a pin roller.  
     
     
         16 . An apparatus for embossing expanded graphite sheet material at a pressure less than atmospheric comprising: 
 (a) means for embossing said material;    (b) an embossing chamber comprising said embossing means, and adapted to receive said material and to be substantially gas-tight at least during embossing; and    (c) means for reducing the pressure in said embossing chamber to less than atmospheric pressure.    
     
     
         17 . The apparatus of  claim 16  wherein said means for reducing the pressure in said embossing chamber reduces said pressure to no greater than about 400 torr.  
     
     
         18 . The apparatus of  claim 16  wherein said means for reducing the pressure in said embossing chamber reduces said pressure to no greater than about 350 torr.  
     
     
         19 . The apparatus of  claim 16  wherein said means for reducing the pressure in said embossing chamber reduces said pressure to no greater than about 170 torr.  
     
     
         20 . The apparatus of  claim 16  wherein said means for reducing the pressure in said embossing chamber reduces said pressure to no greater than about 50 torr.  
     
     
         21 . The apparatus of  claim 16  further comprising means for providing an inert atmosphere within said embossing chamber.  
     
     
         22 . The apparatus of  claim 16  further comprising sealing means for maintaining a substantially gas-tight seal within said embossing chamber at least during the embossing of said material.  
     
     
         23 . An apparatus for embossing expanded graphite sheet material, said apparatus comprising: 
 (a) a chamber adapted to receive said material and to maintain a reduced pressure less than atmospheric pressure at least when said material is in said chamber;    (b) means for reducing the pressure in said chamber to less than atmospheric pressure; and    (c) means for embossing said material.    
     
     
         24 . The apparatus of  claim 23  wherein said means for reducing the pressure in said chamber reduces said pressure to no greater than about 400 torr.  
     
     
         25 . The apparatus of  claim 23  wherein said means for reducing the pressure in said chamber reduces said pressure to no greater than about 350 torr.  
     
     
         26 . The apparatus of  claim 23  wherein said means for reducing the pressure in said chamber reduces said pressure to no greater than about 170 torr.  
     
     
         27 . The apparatus of  claim 23  wherein said means for reducing the pressure in said chamber reduces said pressure to no greater than about 50 torr.