| 摘要 |
1,264,832. Suction dredging. INGENIEURSBUREAU VOOR SYSTEMEN EN OCTROOIEN "SPANSTAAL" N.V. 8 April, 1969 [8 April, 1968], No. 17945/69. Heading E1F. In a method of sucking sand from ground in which the sand occurs beneath a layer of silt or other soil, by using a suction dredger installation provided with a suction pipe, the suction mouth of the pipe is positioned beneath ground level and a physical property of the soil at two levels above the suction mouth is measured to determine the height of the sand in the soil above the mouth. The difference in pressure between the two levels in the soil may be ascertained by measuring devices which are attached to the suction pipe and measure the actual pressures at these levels or the difference in pressure between each of these levels and a pressure above the ground, or the difference in pressure between the two levels. The difference in pressure between a plurality of levels may be measured. Alternatively measurements of viscosity, electrical resistance or transmittivity of rays may be made. |
