| 摘要 |
A method of, and apparatus for, detecting level and blockages in an ore pass or other near-vertical shaft is described. The level and blockage detector includes a flexible metal strip in which a plurality of strain gages have been located, spaced apart from one another, preferably at known distances. A plurality of anchors secure the metal strip to the interior surface of the shaft such that the metal strip is displaced a fixed distance from the interior surface. The anchors are located intermediate the strain gages. When the ore pass fills up with bulk material, the bulk material causes the metal strip to deflect toward the interior surface of the shaft. This causes the resistance of the strain gage in the region of the deflection to change. To detect the location of the blockage, a microcontroller cycles through each strain gage, placing it as the fourth arm of a bridge circuit. When a change in the output voltage across the bridge circuit is detected, the location of the strain gage causing the change in output voltage is an indication of the presence of bulk material (ore). A series of LEDs, one for each strain gage, may be used to indicate which strain gage senses the presence of bulk material and which strain gage does not.
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