Pressureless irrigation device

A pressureless irrigation device, comprising:

• an irrigator for the pressureless irrigation device, wherein the irrigator comprises
• an equal-diameter downstream tee joint (1),
• a horizontal water inlet end (1-1) of the equal-diameter downstream tee joint,
• a horizontal water outlet end (1-2) of the equal-diameter downstream tee joint,
• a vertical water inlet end (1-3) of the equal-diameter downstream tee joint,
• a connecting pipe (2),
• a reducer pipe (3),
• a soil saturated water layer forming pipe (4),
• a porous water-permeable plate (5),
• a sandstone inverted filter layer (6) and
• backfill soil (7);
• the equal-diameter downstream tee joint (1) is connected to capillary pipes in series underground;
• the horizontal water inlet end (1-1) of the equal-diameter downstream tee joint is connected with a head end direction of each of the capillary pipes;
• the horizontal water outlet end (1-2) of the equal-diameter downstream tee joint is connected with a rear end direction of each of the capillary pipes;
• head ends of all the capillary pipes are communicated with a water supply water level control pool (201) by water supply branch pipes and water supply main pipes;
• the vertical water inlet end (1-3) of the equal-diameter downstream tee joint is connected with a small head of the reducer pipe (3) by the connecting pipe (2);
• a lower end of the soil saturated water layer forming pipe (4) is vertically inserted into a large head of the reducer pipe (3);
• the porous water-permeable plate (5) is arranged at the bottom of the soil saturated water layer forming pipe (4) and on one side of the large head of a diameter reducing position of the reducer pipe (3);
• the sandstone inverted filter layer (6) is arranged on the porous water-permeable plate (5);
• the backfill soil (7) is placed on the sandstone inverted filter layer (6);
• a distance between a top end of the soil saturated water layer forming pipe (4) and a soil surface of an irrigated farmland is 40-45 cm;
• a height adjustment range of a soil saturated water layer is from the bottom of the backfill soil (7) in the soil saturated water layer forming pipe (4) to a top of the soil saturated water layer forming pipe (4);
• and
• a height of the soil saturated water layer is adjusted by adjusting a water level of the water supply water level control pool (201).