Online replacement method for scraper chain of submerged chain conveyor

The invention discloses an online replacement method for a scraper chain of a submerged chain conveyor. The online replacement method comprises the steps that an upper cover plate, a stairway and a lower cover plate at a tensioning wheel at the tail of the submerged chain conveyor are dismounted firstly, so that an opening is formed in the tensioning wheel at the tail of the submerged chain conveyor, and meanwhile a scraper chain outlet is formed in the position, close to a tail guide wheel, of a bin shell; the old scraper chain in the submerged chain conveyor is disconnected at the position between the tail guide wheel and the tensioning wheel, and the end, close to the tail guide wheel side, of the old scraper chain is taken out of a bin from the scraper chain outlet and then connected with the work end of a winch through a steel wire rope; the end, close to the tensioning wheel side, of the old scraper chain is connected with one end of a new scraper chain, the submerged chain conveyor is started, meanwhil