... called check valve), more use in the pipe and water channels for water and wastewater treatment engineering , Used for excessive or ... 0.25mpa~2.0mpa(for 150LB)Media: watersuitable for Sea water, sewage, oilproduct descriptiondesign&manufacture standard:ASME,EN,DIN,ISOconnection ... to various vertical shaft manhole cover; Only for one-way water flow of round, square or rectangular export, the structure is ...