Outer blocking prevention nozzle

The utility model discloses an outer blocking prevention nozzle on a spraying and dedusting device of roller type coal mining machine. The outer blocking prevention nozzle comprises a shell; a cavity of the shell is sequentially machined to be a diffusion hole, a circular trepanning, an inner threaded hole; the circular trepanning of the shell is internally provided with a sliding spray core in a sleeving manner, and a gap is formed between the circular trepanning and the sliding spray core and leads the sliding spray core to slide in the circular trepanning; a spraying through hole is arranged at the center of the sliding spray core; a raised edge is arranged at the periphery of the water entering end of the sliding spray core; an O-shaped sealing ring is sleeved at one side of the raised edge close the circular trepanning; the inner threaded hole of the shell is internally connected with a limit rotating core through threads; one end of the limit rotating core opposite to the sliding spray core is fixedly c