Orifice flanges are used with orifice flow meters for the purpose of measuring the flow rate of either liquid or gases  in the inspection pipeline.  Pairs of pressure “tappings”, mostly on two sides, directly opposite each other, are  machined into the orifice flange. This  makes separate orifice carriers or tappings in the pipe wall unnecessary. 

Aceco manufactures a wide range of steel orifice and companion flanges for the energy industry.