| 摘要 |
1309438 Suction dredgers ORENSTEIN & KOPPEL AG 4 June 1970 [4 June 1969] 27112/70 Heading E1F Means are associated with a trailed suction head of a dredger to determine the pressure differential existing between the pressure inside the head and the pressure outside the head and to adjust vertically, in accordance with the determined pressure differential, a slide valve 5 bounding the rear of the suction mouth of the head so as to vary the height of the rear edge of the head as defined by the lower edge of the valve 5 to maintain the pressure differential to an optimum value for operational efficiency of the head. In the form shown the valve 5 is secured to one end of a flexible, unstretchable band 7 forming a diaphragm of an open top chamber 9 on the head. The band is anchored at 10 to the chamber to have a sealed but movable relationship with the other walls of the housing, which is connected to the inside of the head through a passage 13. In alternative embodiments the valve 5 is connected by a guided band or rope or a linkage to a piston in a cylinder to which the pressure differential is applied. The valve or the piston may be spring loaded to allow of variation of the operational range of adjustment of the valve. |
