Manhole sealing cover plate for scraper chamber of coal mill

The utility model discloses a manhole sealing cover plate for a scraper chamber of a coal mill. The manhole sealing cover plate comprises a manhole cover plate, a segmented variable-diameter cylinder, a first asbestos packing, a screw rod and a hand wheel, a manhole cover plate is hinged to one side of the inspection manhole, a round hole is formed in the plate face, opposite to the inspection manhole, of the manhole cover plate, and a cylindrical cavity communicated with the round hole is formed in the manhole cover plate. The segmented variable-diameter cylinder comprises a large-diameter section, a middle-diameter section and a small-diameter section which are sequentially connected, the large-diameter section of the segmented variable-diameter cylinder is movably clamped in the cylindrical cavity of the manhole cover plate, and the middle-diameter section of the segmented variable-diameter cylinder movably penetrates through the round hole; a threaded hole is formed in the plate face, away from the inspec