Granulation screen with long service life and protective layer spraying device

The invention relates to the technical field of dry granulation equipment, and discloses a long-service-life whole-grain screen and protective layer spraying device which comprises a screen and a nitriding layer arranged on the surface of the screen, and further comprises a supporting bottom frame, a first spraying device and a second spraying device. The first spraying device and the second spraying device are slidably clamped to the upper end of the supporting bottom frame, the first spraying device and the second spraying device are the same in structure, sliding supporting brackets are symmetrically slidably clamped into the supporting bottom frame, and supporting moving brackets are fixedly mounted at the upper ends of the sliding supporting brackets. After the nitriding layer is sprayed on the outer surface of the screen, a nitriding layer protection layer is formed on the surface of the screen, so that the corrosion resistance, the hardness and the impact resistance of the steel wires in the screen are