Answer: (1) According to the opening height.
1) Micro-opening safety valve: the opening height of the valve disc is 1/15~1/20 of the inner diameter of the valve seat.
2) Full-opening safety valve: the opening height of the valve disc is 1/3~1/4 of the inner diameter of the valve seat.
3) Medium-opening safety valve: the opening height of the valve disc is between micro-opening and full-opening.
(2) According to the structural form. ① Lever weight safety valve; ② Spring safety valve; ③ Pulse safety valve (also known as pilot safety valve); ④ Micro-opening safety valve; ⑤ Full-opening safety valve; ⑥ Fully enclosed safety valve; ⑦ Semi-enclosed safety valve; ⑧ Open safety valve.
(3) The safety valve used in screw air compressors is a micro-opening safety valve with a wrench spring.
