Cover pressing device and oil extraction system

The utility model relates to a gland device and an oil extraction system, and belongs to the field of oil and gas exploitation. The gland device comprises a gland box, a blowout prevention ball and anelastic assembly, one end of the elastic assembly is fixedly connected with the blowout prevention ball, and the other end of the elastic assembly is fixedly connected with the gland box. A first through hole formed in the first direction and a second through hole formed in the second direction are formed in the gland box, and the first through hole and the second through hole are crossed; the first through hole is used for allowing a polish rod to pass through and is communicated with a polish rod through hole of a Christmas tree; and the blowout prevention ball and the elastic assembly aresequentially arranged in the second through hole in the direction away from the crossed position, and the blowout prevention ball is configured to block the first through hole at the crossed positionunder the elastic action of