Pitch based foam and apparatus for extruding pitch based foam

Abstract

A method and apparatus for extruding pitch based foam is disclosed. The method includes the steps of: forming a viscous pitch foam; passing the precursor through an extrusion tube; and subjecting the precursor in said extrusion tube to a temperature gradient which varies along the length of the extrusion tube to form an extruded carbon foam. The apparatus includes an extrusion tube having a passageway communicatively connected to a chamber in which a viscous pitch foam formed in the chamber passes through the extrusion tube, and a heating mechanism in thermal communication with the tube for heating the viscous pitch foam along the length of the tube in accordance with a predetermined temperature gradient.

What is claimed is:  
     
         1 . A method of extruding a pitch based foam comprising the steps of: 
 forming a viscous pitch foam;    passing said viscous pitch foam through an extrusion tube to form an extruded foam; and    heating said extruded foam in said extrusion tube in accordance with a predetermined temperature gradient to coke said extruded foam.    
     
     
         2 . The method of  claim 1 , in which said extruded foam is further heated in accordance with said predetermined temperature gradient to form an extruded carbon foam.  
     
     
         3 . The method of  claim 2 , in which said extruded carbon foam is further heated in accordance with said predetermined temperature gradient to form a graphite foam.  
     
     
         4 . The method of  claim 1 , in which said temperature gradient reaches a maximum of between 500 and 650° C.  
     
     
         5 . The method of  claim 2 , in which said temperature gradient reaches a maximum of about 1000° C.  
     
     
         6 . The method of  claim 3 , in which said temperature gradient reaches a maximum of about 2800° C.  
     
     
         7 . The method of claims  1 , including sectioning said extruded foam.  
     
     
         8 . The method of  claim 1 , in which the step of forming a viscous pitch foam includes the steps of: 
 melting pitch in a melting chamber to form molten pitch    transporting said molten pitch to a foaming chamber; and    foaming said molten pitch in said foaming chamber to form said viscous pitch foam.    
     
     
         9 . The method of  claim 8 , including agitating said molten pitch in said melting chamber to ensure uniform pitch temperature and homogeneity  
     
     
         10 . The method of claims  8 , in which the pitch is selected from the group consisting of: mesophase pitch, isotropic pitch, coal derived pitch, petroleum derived pitch, solvent extracted pitch, or solvated pitch.  
     
     
         11 . A pitch based foam made in accordance with  claim 1 .  
     
     
         12 . An apparatus for extruding a pitch based foam, said apparatus comprising: 
 a melting chamber for melting pitch;    a foaming chamber communicatively connected to said melting chamber for foaming said melted pitch to form a viscous pitch foam; and    a heated extrusion tube having a passageway communicatively connected to said foaming chamber, wherein said viscous pitch foam formed in said foaming chamber passes through said extrusion tube passageway to form an extruded pitch based foam.    
     
     
         13 . The apparatus of  claim 12 , in which said heated extrusion tube heats said viscous pitch foam in accordance with a predetermined temperature gradient along the length of said tube.  
     
     
         14 . The apparatus of  claim 12 , in which said heated extrusion tube heats said viscous pitch foam using a heating method selected from the group consisting of radiant energy, microwave energy, and induction heating.  
     
     
         15 . The apparatus of  claim 12 , including a sectioning mechanism for sectioning said extruded carbon foam.  
     
     
         16 . The apparatus of  claim 12 , including an agitating mechanism for agitating said melted pitch to ensure uniform pitch temperature and homogeneity.  
     
     
         17 . The apparatus of  claim 16 , in which said agitating mechanism is a mixing shaft having a mixing end  
     
     
         18 . The apparatus of  claim 16 , in which said agitating mechanism is a feed screw.  
     
     
         19 . The apparatus of  claim 12 , including a metering pump for transferring said melted pitch from said melting chamber to said foaming chamber.  
     
     
         20 . The apparatus of  claim 12 , in which said extrusion tube passageway is shaped for shaping said viscous pitch foam to have a predetermined cross section.  
     
     
         21 . The apparatus of  claim 12 , in which said melting chamber and foaming chamber are the same chamber.  
     
     
         22 . An apparatus for forming an extruded pitch based foam from a viscous pitch foam formed in a chamber comprising: 
 an extrusion tube having a passageway communicatively connected to a chamber in which a viscous pitch foam formed in said chamber passes through said extrusion tube; and    a heating mechanism in thermal communication with said tube for heating said viscous pitch foam along the length of said tube in accordance with a predetermined temperature gradient.    
     
     
         23 . The apparatus of  claim 22 , in which said extrusion tube passageway is shaped for shaping said viscous pitch foam to have a predetermined cross section.