Oil—water separator

Apparatus for separating a mixture of oil and water into two fractions:

• an oil fraction comprising primarily oil, and a water fraction comprising primarily water;
• wherein the oil fraction may optionally comprise one or more minor components in addition to oil, and wherein the water fraction may optionally comprise one or more minor components in addition to water;
• wherein said apparatus comprises:
• (a) a first chamber and a second chamber, wherein said first and second chambers are fluidly connected to one another only at or near the bottoms of said first and second chambers;
• (b) an inlet adapted to transport a mixture of oil and water from an external source into said first chamber;
• (c) a low-shear or non-emulsifying pump adapted to transport the mixture of oil and water from the external source, through said inlet, and into said first chamber;
• (d) an oil outlet adapted to transport the separated oil fraction from said first chamber;
• and
• (e) a water outlet adapted to transport the separated water fraction from said second chamber;
• wherein:
• (f) said oil outlet has a higher elevation than said water outlet;
• (g) the respective elevations of said oil and water outlets above the fluid connection between said first and second chambers, and the dimensions of said first chamber are such that said apparatus is adapted to operate as follows:
• (i) said pump transports the mixture of oil and water from an external source, through said inlet, and into said first chamber;
• (ii) within said first chamber, the turbulence and velocity of fluid flow are sufficiently low that the mixture separates by density into an lighter, upper, oil fraction and a denser, lower, water fraction;
• (iii) the continued inflow of liquid forces liquid in the denser, lower, water fraction—but not liquid in the lighter, upper, oil fraction—to flow from said first chamber through the fluid connection into said second chamber, thereby separating a water fraction;
• (iv) the continued inflow of liquid forces liquid in the separated water fraction in said second chamber through said water outlet;
• (v) the continued inflow of liquid forces liquid in the separated oil fraction in said first chamber through said oil outlet;
• and (vi) the difference in elevation between said oil and water outlets, together with the difference in densities between the separated oil and water fractions, and the presence of the fluid connection between said first and second chambers ensure that essentially none of the water fraction reaches said oil outlet;
• (h) a portion of said first chamber adjacent to said inlet is substantially wider than other portions of said first chamber;
• wherein the dimensions of the wider portion of said first chamber are sufficiently large to inhibit the development of turbulence within said first chamber;
• and wherein the narrower portions of said first chamber are at least sufficiently wide not to substantially impede the flow of liquid through said first chamber;
• (i) said first and second chambers are dimensioned so that, when said apparatus is placed in a body of water, the center of gravity of said apparatus lies below the surface of the body of water, and so that the wider portion of said first chamber lies fully or partially below the surface of the body of water;
• (j) said apparatus is adapted to be mounted in a ship or a boat, or is adapted to be towed in the water behind a ship or a boat;
• and
• (k) said apparatus is adapted to operate, as described in limitation (g) above, in situ, to separate a mixture of oil and water while said apparatus is moving on a body of water, without any necessity to first transport the mixture of oil and water onshore or to a stationary location before the oil fraction and water fraction are separated from one another.