Patent GB-1470640-A (GB)
Title: Process and an apparatbs for graphitising carbon bodies
IPC: F27D11/04
Filed: 1975-12-02
Abstract: 1470640 Tunnel furnace SIGRI ELEKTROGRAPHIT GmbH 2 Dec 1975 [17 Dec 1974] 49531/75 Heading F4B [Also in Division H5] A tunnel furnace for use in the graphitization of carbon bodies comprises a furnace duct (Fig. 1) having a preheating zone 2, a graphitization zone 3 and a cooling zone 4, in which the carbon bodies are to be positioned, in use, in turn, and which intercommunicate in such a manner that the thermal content of the graphitized bodies produced in the graphitization zone can be used to pre-heat bodies to be graphitized and thereby reduce the temperature of the graphitized bodies to below 500 C. while in the cooling zone, the furnace duct having wall means provided with holding means 20, 20<SP>1</SP> (Figs. 2 and 3) for holding the bodies in the zones, the holding means in the graphitization zone being in the form of contact pieces 20<SP>1</SP> (graphite pieces specified), electrically connected 23, in use, to a current source 24 (preferably D.C.) capable of heating bodies held therebetween to a temperature of at least 2000C., by resistance heating of the bodies, the furnace further comprising displaceable wall means 7, 7<SP>1</SP>, 8, 8<SP>1</SP>, displaceable transversely of the direction of movement of the bodies through the furnace for closing off sections of the furnace one from the next and carrying means 19 mounted for displacement in both the horizontal direction along the course of the furnace duct, and the vertical direction and intended to engage periodically the bodies for and during the displacement and to disengage the bodies when the bodies are held by the holding means. The furnace duct may have below it a second duct 14, which communicates with the furnace duct through a slit-form opening, and which accommodates, on rails, a succession of trolleys 15 each carrying a pallet 18 and the carrying means 19 for carbon or graphitized carbon bodies and means 17 for the vertical displacement thereof, which pallets substantially wholly occupy the slit-form opening between the ducts. The graphitization zone may be arranged at one end of the furnace duct and the pre-heating and cooling zones at the other (Fig. 5), so that the bodies can be preheated by radiant heat emitted by graphite bodies undergoing cooling, there being arranged below the furnace duct a pair of further ducts each of which communicates with the furnace duct through a slitform opening and each of which accommodates trolleys 15 carrying a pallet 18 and carrying means 19, the holding means for the bodies in the graphitization zone may then be adapted for the lateral transfer of the bodies from a position above one slit form opening to a position above the other (Fig. 6). Alternatively, heat may be transferred from the cooling to the pre-heating zone by means of an inert gas which is recycled (Fig. 1), optionally after scrubbing 51 carbonisation products therefrom. The pre-heating, graphitisation and cooling zones may be arranged around an annular furnace duet below which is disposed a second annular duct, communicating therewith through a slit-form opening, the second duct accommodating a succession of trolleys each carrying a pallet which substantially completely occupies the slit-form opening between the ducts. In a modification of the annular furnace (Fig. 7), the graphitization zone 31 is positioned adjacent the furnace duct, means 27 are provided for the displacement of the bodies from the annular furnace duct to the graphitization chamber 31 to be held by holding means therein and electricity supply means 23, 24 for passing electric current through the bodies when held in the graphitization chamber to effect graphitization thereof. The furnaces of the invention may be insulated with layers of carbon non-woven fabric (felt) and/or graphite foils and are generally surrounded by a gas-tight steel jacket having trickle-cooling means for cooling the furnace with water.