standard:Q/TF-B27P.01,BS,ISO,DIN
PN10,PN16
DN50-300
material:grey cast iron,ductile iron
leakage:GB/T 13927 class A

There is a large and a small orifices. The large one can intake and release large amount of air. The air way of the large orifice is sym-metrical which makes the air releasing amount more than that of the same size doubles roifices air releasing valve. The suitable pipeline is DN100-3000mm.