1. Equipped with a spring, used to push the valve disc open under negative pressure, and help the valve disc close after the pressure returns to normal. This design ensures fast response and stable performance of the valve.

2. Outside the valve cover, an intake grid plate is installed to ensure that gas can enter and discharge the valve smoothly.

3. The interior of the valve body is lined with fluorine to withstand the erosion of a variety of corrosive media, and the dovetail groove structure prevents negative pressure from forming a bulge on the lining, thereby extending the service life of the valve.