Sealing device of internal mixer

The invention provides a sealing device of an internal mixer. The sealing device of the internal mixer enables materials in a cavity to be reliably sealed and ensures the sealing performance of the whole internal mixer. Pressing and attaching supports are arranged at the two ends of a connecting shaft respectively; the two ends of the connecting shaft penetrate through connecting holes of the corresponding pressing and attaching supports respectively; a stop ring is arranged on the end face, corresponding to the pressing and attaching support at each end, of the connecting shaft; a circle of inwards-concave stop groove is formed in the inner diameter area, corresponding to the connecting hole, of each stop ring; triangular threaded grooves is formed in the positions, corresponding to the axis length area of the connecting holes, on the outer ring of the connecting shaft; spiral sleeves are in threaded connection with the triangular threaded grooves; the inner ends of the spiral sleevesare inserted into the inwards-concave stopping grooves in a matched mode; the peripheries of the stop rings at the outer ends of the spiral sleeves are tightly attached to the stopping end faces of the pressing and attaching supports; first fastening screws which are annularly distributed are fixedly connected with the corresponding positions of the spiral sleeves and the pressing and attaching supports; and sealing seats are further arranged in the axial directions of the pressing and attaching supports, protruding out, on the connecting shaft.