| 摘要 |
The invention relates to a device for accurate subaqueous measurements of the vertical displacements of a reference point e.g. the head of a pile by using a pressure difference recorder at the reference point which measures the difference between an air filled chamber and the water pressure outside said chamber, said recorder being bridged by a tube interconnecting the two pressure regions and having a valve which in the open position interconnects the two regions said air chamber being located above the recorder while the valve has an electromagnetic operating member placed in a circuit with the recorder and a measuring device, the initial pressure in the air chamber being the atmospheric pressure at the water surface. There may be two identical devices each having a switch in the circuit of the recorder which brakes the circuit at the end of the measuring range, the switches of the two devices operating such that when one interrupts the other makes its circuit. |
