Patent ID: 6923631

Claim:
A system for the continuous production of surface patterned, resin-impregnated flexible graphite sheet which comprises: (i) a reactor vessel for containing as reactants raw natural graphite particles in mixture with sulfuric and nitric acids; (ii) an acid containing vessel communicating with said reactor vessel for the introduction of a mixture of sulfuric and nitric acid into said reactor vessel; (iii) a graphite particle containing vessel for the introduction of graphite particles into the reactor vessel; (iv) a first additive containing vessel communicating with said reactor vessel for the introduction of intercalation enhancing materials, acids or organic chemicals; (v) a wash vessel containing water communicating with the reactor vessel to receive reaction product in the form of acid intercalated graphite particles and remove acid from the surface of the acid intercalated graphite particles and a portion of the mineral impurities contained in the natural graphite particles introduced into the reactor vessel; (vi) a drying chamber for drying washed acid intercalated graphite particles; (vii) conduit means extending from said wash vessel to said drying chamber for passing washed acid intercalated graphite particles from the wash vessel to the drying chamber; (viii) an expansion chamber enclosing an open flame at a temperature of at least about 700° C.; (ix) conduit means extending from said collecting vessel to said expansion chamber for passing dried acid intercalated graphite particles to said expansion chamber; (x) gas inlet means communicating with the conduit means of (viii) for entraining the acid intercalated graphite particles in a stream of non-reactive gas and passing the entrained acid intercalated graphite particles into the open flame enclosed in said expansion chamber to cause expansion of the acid intercalated graphite particles to form vermiform elongated graphite particles; (xi) a collecting hopper for receiving said vermiform elongated graphite particles; (xii) a compression chamber positioned to receive vermiform graphite particles for compressing said vermiform particles into a coherent self-supporting mat of flexible graphite; (xiii) an impregnation chamber for contacting the flexible graphite mat of (xviii) with resin and impregnating said flexible graphite with resin; (xiv) a calender mill disposed to receive the flexible graphite mat for increasing the density of said flexible graphite mat to form a continuous flexible graphite sheet; (xv) a device for mechanically deforming a surface of the continuous flexible graphite sheet of (xiv) to provide a series of repeating patterns on said surface flexible graphite sheet or the removal of material from said flexible graphite sheet in a series of repeating patterns; and (xvi) an oven for receiving the mat from the dryer of (xv) to cure the resin.