Abstract: In a separator for separating a mixture of fluids of different densities into a high density fraction and a low density fraction, the mixture is introduced into a tank which is divided into a plurality of separation chambers and a collection chamber. As the mixture flows through the chambers it is separated into high and low density fractions with progressively more distinct differentials of density. The rate of fluid flow through the separator is controlled in part by the size of the separation chambers and by an automatic electro-mechanical control system. The control system includes several floats suspended within the fluids, wherein the level of at least one float is indicative of the level of high density fraction in the separator, and the level of at least one other float is indicative of the level of the low density fraction in the separator.