... years OEM manufacturer experience Rubber Duckbill Valve,duckbill valve,slip on duckbill check valveThe rubber Duck-bill check valve is ... maintenance2, There is smaller resistence in forward start,small pressure to start,in addition,the flux can be adjusted automatically according ... figure5)Certificates obtained:Rubber Duckbill Valve,duckbill valve,slip on duckbill check valve For Sewage Treatment slip ...