| 摘要 |
<p>Used rolling mill oil, contaminated with water, solid material and tramp oil, is purified by collecting the used oil in a settling tank, withdrawing from the lower region of the tank a dense fraction which is centrifuged to separate a light oil-containing fraction and a heavy water-containing fraction, mixing the thus separated light fraction with a less dense oil and water fraction withdrawn from an intermediate region of the settling tank, and centrifuging this mixture to obtain a purified rolling oil stream and a stream of water containing the tramp oils. This latter stream may be passed to a second settling tank, and separating the upper layer of tramp oil from the underlying water layer, which may be fed back to the first settling tank or the second centrifuge. Specification 895,997 is referred to.</p> |
