The invention pertains to a key device for water-saving
irrigation, which is a wall-attached fluidic
nozzle that realizes variable spraying; the
nozzle comprises a static plate, a moving plate, a spraying body, a spraying tube, a rotating seal mechanism, a knighthead, a spacing ring, a reversing mechanism and a fluidic element body and is characterized in that the static plate and the moving plate are added to a
nozzle spin; the moving plate is pressed to match a hollow shaft, and rotates along with the nozzle. The fluidic element body comprises a reverse air supply nozzle, a
signal water receiving nozzle, an outlet cover plate, a
signal water intake nozzle and a
honeycomb duct;
signal water in a signal water receiving nozzle leads one side of main jet-flow to form a low-pressure spiral area at intervals; by opening and closing an air supply receiving nozzle, the other side of the main jet-flow is led to switch between
high pressure and low pressure so as to form a
differential pressure between the right and the left ends of the main jet-flow, thus realizing the wall attachment of
water flow and finishing direct spraying, stepping and reverse running of the nozzle. The static plate and the moving plate at the position of the nozzle spin move relatively to change the area of stopflow at an inlet and regulate the flow and the pressure of the inlet so as to change the spraying range of nozzle and realize variable spraying.