| 摘要 |
<p>A liquid level gauge which utilizes the electrical resistance of the liquid being gauged to provide readings. An immersion unit is adapted to be disposed vertically in the liquid storage vessel. It comprises an elongate conducting member coextensive with a row of insulatedly-mounted electrodes which letter are individually connected to an indicating type selector switch means. The conducting member is connected to one input of an extremely sensitive electronic amplifier, which in turn drives an output indicating meter. The indicating selector switch means can apply an energizing voltage to any of the electrodes, which results in A driving signal applied to the amplifier only if the energized electrode is submerged. An indicator light signals the amplifier output under such circumstances. By sweeping the selector switch means over its range and noting the point at which the indicator light becomes illuminated, it is possible to acertain the location of the upper-most electrode which is submerged and thus determine the level of fluid in the tank. In addition, the indicating meter provides a reading corresponding to the percentage or portion of the electrode which is submerged, and thus gives a finer degree of accuracy to the level measurement. An electrical guard surrounds the conducting member and electrodes, and means are provided for maintaining both the guard and the electrodes which are not energized at a potential equal to that sensed by the conducting member. The advantage of the present device over prior types is that the potential which the conducting member senses is not adversely influenced by proximity of the immersion unit to other objects in the tank. Improved reliability and accuracy are thus realized.</p> |
