A closure mechanism to inhibit escape of heat from an oven chamber of a conveyor oven having a conveyor hanger. The closure mechanism includes a plurality of plates configured to couple to a first and second pluralities of connection tabs of a conveyor oven. Each of the plurality of plates include a connection portion, an angled portion configured to extend downward from the connection portion within a slot of the conveyor oven and an engagement portion extending downward from the angled portion to form an engagement surface.

The present disclosure relates to a graphitization apparatus for manufacturing artificial graphite using lasers, including: a first chamber having doors located on both walls thereof in such a way as to be open when saggars go in and out and providing a workspace for graphitization of raw materials filled in the saggars; a laser heater consisting of a plurality of laser systems and irradiating laser beams onto the raw materials introduced into the first chamber to graphitize the raw materials; and a first transfer conveyor for sending the saggars filled with the raw materials to the first chamber and taking the saggars out of the first camber after the graphitization has been completed.