1.Regulate the screw ② , keep the center of the spring support axis with the center of the superstructure.2.Regulate the screw ① , make the door stop at its intended position3.Regulate the screw ③ , keep the door parallel to the ground and springs;Regulate thescrew ① , make the door stop at the central position.4.Slowing down by returning the valve clockwise with the closing velocity of the first section and the braking velocity of ② section. Turning the valve counterclockwise with the closing velocity of the first section and the braking velocity of ② section to accelerate the velocity