| 摘要 |
PROBLEM TO BE SOLVED: To collect sand in high concentration without being affected by water depth and an ocean current. SOLUTION: In a controller for a submerged sand pump A, by which soil and sand on the bottom of water G sent into water through wires W from a water surface such as a ship S are sucked up to a sand selector M on water through a collecting hose P. The wires W are delivered and taken up and the quantity of soil and sand sucked into the submerged sand pump A is controlled so that the volume and concentration of sucked-up soil and sand are kept within fixed ranges. When concentration is too high, the pump A is positioned in a posture in high load, in which the pump A is buried in soil, and there is the possibility of the damage of the pump. When concentration is too low, inversely, the pump is not faced excellent into soil, and positioned in a posture, in which proper sand collection is not conducted. Accordingly, when the pump reaches fixed concentration width, the optimum posture states of the pump A can be predicted, and smooth sand collection can be conducted. Volume and concentration are computed by multiplying measured values for a unit time of a flowmeter 1 and a densitometer 2 in response to the quantity of sand collected properly.
|
