Online repairing device and method for dry quenching high temperature metal expansion joint

The invention provides an online repairing device and method for a dry quenching high temperature metal expansion joint, and belongs to the technical field of coking equipment maintenance tools and methods. According to the technical scheme, two semicircular sealing clamping rings are welded to the upper ends of two semicircular sealing guide sleeves respectively, the two semicircular sealing clamping rings and the two semicircular sealing guide sleeves are connected into a whole through connecting flanges, an upper sealing check ring and carbonized fiber packing are placed between the circumferential inner walls of the sealing clamping rings and an upper end pipe of a high temperature metal expansion joint, two semicircular sealing bodies are located in the circumferential inner walls of the lower ends of the two semicircular sealing guide sleeves respectively, the carbonized fiber packing is placed between the circumferential inner walls of the sealing guide sleeves and the sealing bodies, and a lower seali