Self-sealing type flat-head pulverized coal sampling gun and operation method thereof

The invention relates to a self-sealing type flat-head pulverized coal sampling gun. The self-sealing type flat-head pulverized coal sampling gun comprises a sampling gun body and a sealing head, wherein the sampling gun body comprises a sampling gun barrel, a sampling gun sampling hole and a sampling gun convex groove, the sampling gun sampling hole is formed in the barrel wall of one end, inserted into a sampling hole, of the sampling gun barrel, and the sampling gun convex groove is welded to the barrel wall of the other side, opposite to the sampling gun sampling hole, of the sampling gunbarrel; and the sealing head comprises a circular sealing cover, a key hole and a hollow cylindrical section, the key hole matched with the sampling gun body is formed in the center of the circular sealing cover, the hollow cylindrical section is arranged at the bottom of the circular sealing cover, an external thread is arranged on the outer surface of the circumference of the hollow cylindricalsection, the external thre