| 摘要 |
<p>COR-123 11/07/85 PATENT A method and apparatus for detecting a change in the liquid level in a liquid storage tank, such as an underground hydrocarbon storage tank. A gas line is inserted just below the level of the liquid in the tank, and a second interconnected gas line is placed in a small liquid cup located on the surface. The differential pressure between the two lines is measured and used to compute the level in the tank. A second measurement taken hours later reveals any change in level indicating a leak. Provision is made to accurately zero the apparatus at each measurement to insure precision.</p> |
