Patent ID: 8501014

Claim:
A separation unit for separating oil from a fluid comprising oil and water in a first oil-to-water ratio, the separation unit comprising: a housing defining an inner chamber having a bottom end defined by a first end-wall, a top end defined by a second end-wall, and one or more side-walls extending between the first end-wall and the second end-wall, the inner chamber being at least partly delimited by the first end-wall, the second end-wall, and the one or more side-walls; a first set of separation walls extending from the first end-wall towards the second end-wall and defining a first set of fluid passages below the second end-wall and above the separation walls of the first set; a second set of separation walls extending from the second end-wall towards the first end-wall and defining a second set of fluid passages above the first end-wall and below the separation walls of the second set, the second set of separation walls being interlayered between the first set of separation walls; an inlet into the inner chamber at or near the bottom end thereof; a first outlet from the inner chamber at or near the bottom end thereof; a set of further outlets from the inner chamber above the separation walls of the first set of separation walls; a fluid path extending from the inlet to the first outlet within the inner chamber, the fluid path passing through the first set of fluid passages and the second set of fluid passages and having a gradually increasing flow restriction from the inlet to the first outlet so as to separate fractions of the fluid having higher oil-to-water ratios than the first oil-to-water ratio flowing from the fluid path to the set of further outlets, and so as to expel fluid having a lower oil-to-water ratio than the first oil-to-water ratio from the first outlet; and a pump connected at the inlet and operable to establish an elevated pressure of the fluid throughout the fluid path.