Patent ID: 8741032

Claim:
A separator tank for separating oil and gas from water, and comprising an essentially cylindrical vertical tank casing and at least two separator tank units, which separator tank unit has an upper part and a lower part, an inlet for fluid, an inner annular wall, at least one first outlet in the upper part of the separator tank unit, at least one second outlet in the lower part of the separator tank unit, and a central pipe extending from the first outlet to the second outlet, the central pipe being blocked with a flow barrier between the first outlet and the second outlet, wherein the central pipe has an upper extension extending out of the separator tank unit and a lower extension extending out of the separator tank unit; said inner annular wall having a first opening at an upper end of said inner annular wall allowing communication between the upper part and the lower part of the separator tank unit, wherein the separator tank comprises an inner annular enclosure that divides the separator tank into an annular outer area and a central area, wherein said at least two separator tank units are arranged on top of one another within the central area separated by an intermediate bottom, wherein the flow paths of fluids to inlets in the separator tank units and from at least one second outlet in the separator tank units are arranged at least in the annular outer area, wherein an inlet on the separator tank is connected with the inlet for fluid in a first of the at least two separator tank units via a first inlet flow path, and the second outlet in the first separator tank unit is connected with the inlet for fluid in a second of the at least two separator tank units via a second inlet flow path.