The Simple Laws of Physics: In a near static condition where the movement of solution is minimal, gravity will separate, from solution, oil (which floats) and sludge (which sinks). Over time, as turbulence (velocity) is reduced, separation increases. The efficiency of separation is inversely proportional to its turbulence. Gravitational separation is best achieved when the solution is in a static state, with no movement at all. According to Better Engineering, "Particles are 'slammed' to the bottom ... and ... filtered water 'cascades' back into the main tank."
In other words, Better Engineering claims that "THE PURIFIER" causes gravity oil-sludge separation through turbulence.
Applying the Laws of Physics: We rely on the following data that are published by the American Petroleum Institute (API):