Pressure-adjustable air safety valve for irrigation

The utility model discloses a pressure-adjustable irrigation air safety valve which comprises a first shell, a second shell and a compression spring, and the first shell is provided with an air inlet and an air outlet; the second shell is connected with the first shell, a diaphragm seat and a disc seat are mounted on the inner wall of the second shell, a first diaphragm is placed on the diaphragm seat, a through hole is formed in the first diaphragm, and the first diaphragm is in sealing contact with the inner wall of the second shell; a disc is placed on the disc seat, and a gap is formed between the disc and the inner wall of the second shell; a pre-tightening spring is mounted on the disc, a second diaphragm is mounted at the upper part of the pre-tightening spring, and the second diaphragm is in close contact with the first diaphragm under the action of the pre-tightening spring so as to seal the through hole; one end of the compression spring is fixed to the top wall of the first shell, the other end of