| 摘要 |
A drop-weight material level indicator in which a spool is mounted above material whose level is to be sensed and is coupled to a motor for selectively unwinding and winding a drop line wound on the spool. The drop line is trained over an idler pulley carried at the end of a pivot arm, and over a second idler pulley to a drop weight. Level sensing electronics are coupled to the second idler pulley for measuring the amount of cable unwound as the drop weight descends toward the upper surface of the material. A magnet is carried on the pivot arm, and a reed switch is positioned adjacent thereto for sensing removal of tension from the drop line and consequent pivotal motion of the arm, and thereby indicating rupture of the drop line to an operator.
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