OK, I'll correct you. The centrifugal separation of oil and water has always been problematic in a decanter centrifuge (continuous process machine) due to the fact that the heavier fraction of the influent settles to the bottom while the lighter fraction rises to the top. In order to trap the lighter oil it is necessary to capture the top most layer of material which has proven to be difficult. Several companies have produced a three phase machine which does allow the top fraction to be collected separately, but they do have their limitations and the material in question would plug the discharge tubes used to collect the upper fractions.