摘要 |
Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A permanent magnet (42) mounted on the diaphragm (30) so moves with diaphragm flexure as to vary the magnetic saturation of a saturable circuit in which the coil (34) generates flux. By determining the coil's inductance under quiescent-diaphragm conditions, a computer (56) can infer the ambient pressure that bears upon the liquid (10). By compensating for the static pressure thus inferred, it can then determine liquid level by observing diaphragm oscillations reflected in coil electromotive force generated by the magnet (42) as the diaphram (30) undergoes oscillatory flexure in response to the coil's momentary excitation.
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