Abstract

An oil retriever for recovering heavy oil, including bunker c, from a body of water is a self-contained unit that is maneuverable independently of land. The retriever has two pontoons that are spaced apart and parallel from one another. Across the front of the pontoons, there is rotatably mounted a cylindrically-shaped drum with closed ends. The drum is light enough to float on the oil and/or water. The drum is rotated about its longitudinal central axis by a reversible variable speed motor. There are two scrapers extending along the entire rearward side of the drum. A first scraper forms a line of contact with the drum but a second scraper is out of contact with the drum. Between the pontoons to the rear of the drum is a storage tank that is initially filled with water. Most of the storage tank is located below the water surface. As the drum is rotated in such a direction that a forward edge moves downward into the oil and water, some of the oil coats the drum surface, the coating being thin enough to pass between the second scraper and the drum. The first scraper removes the oil and it falls back towards the second scraper. The oil then falls onto the lower scraper and from the lower scraper into the storage tank. A base of the storage tank contains a valve, which is open during the collection process. As the oil builds up in the storage tank, it will float on the surface of the water and will steadily force the water present in the storage tank out the valve. When the tank is filled or nearly filled with oil, the valve is closed, the tank is removed from the retriever and emptied or replaced by a new tank. If the oil is thin enough to be pumped, the tank can be left in the retriever while the oil is pumped out of it. Subsequently, more oil can be collected to refill the tank and the process can be repeated. Previous oil retrievers are relatively inefficient when used to recover heavy oil, particularly when the oil is located in cold water and forms a cohesive sticky mass.