Patent ID: 6849176

Claim:
An oil/grease separator to separate a heavier liquid from a mixture of the heavier liquid and a lighter liquid with which the heavier liquid is immiscible comprising a housing having an inner volume, an inlet into the inner volume to receive an influent flow of a mixture of the heavier liquid and the lighter liquid with which the heavier liquid is immiscible, a first outlet from the volume to discharge the heavier liquid positioned such that the outlet defines a static liquid level in the housing, and a second outlet positioned in the housing so substantially all of the lighter liquid held in the volume can flow to the second outlet and above the static liquid level in the housing, so that as surges of influent flow are received in the housing and temporarily raise the liquid level above the static liquid level, lighter liquid on top of the heavier liquid in the volume is discharged from the second outlet, together with heavier liquid, a storage vessel to receive the liquid from the second outlet, and a return path from a low portion of the storage vessel to the housing to return heavier liquid from the storage vessel to the housing, whereby the lighter liquid in the housing tends to float on the heavier liquid in the housing, so that transient large volume flows into the inlet of the housing have minimal tendency to disturb the floating lighter liquid and therefore do not cause substantial discharge of lighter liquid with the heavier liquid through the first outlet.