| 摘要 |
What is indicated is a feeder for bulk material, especially for sand or gravel, which contains a periodically actuated metering element delivering the bulk material out of a supply silo onto a conveyor band. In order to guarantee a uniform feed even when the bulk material has no uniform grain composition and contains a high proportion of dirt and water, the feeder is assigned a sensing device which senses the height of the fed bulk material and which switches off the drive of the metering element when the bulk material exceeds a predetermined height, and which switches the drive of the metering element on again as soon as the height falls below a predetermined value again. This automatically ensures that never more bulk material than can subsequently be transported is fed. The sensing device consists either of a pivoting lever with a hollow body arranged at its free end and floating on the fed bulk material, the control for the drive of the metering device taking place in dependence on the pivoting position of the pivoting lever, or there are provided two electrodes of different length which form a circuit via the bulk material and which, via a relay, control the drive of the metering element in dependence on the height of the fed bulk material. <IMAGE>
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