Operation principle 1. Operated by Air/Spring, Air / Air 2. Compressed air push shaft to open and close valve 3. Valve structure: Valve seat opens construction inside so that it can avoid pushing when pipeline is over pressure 4. Parts in contact with the products: AISI 316L,AISI 304 5. Other parts: AISI 304 6. Gaskets (standard): EPDM according to FDA 177.2600 7. Internal surface finish: Ra≤0.8μm 8. External surface finish: Mirror polish