| 摘要 |
<p>A tether-free sensor unit of spherical or ellipsoidal shape with no motorized propelling means is disclosed. The sensor unit is for inspecting a pipeline which contains a moving liquid, and it comprises a package containing a sensor selected from at least one magnetic sensor and at least one accelerometer, and recording means for recording data sensed. The sensor unit is of greater density than the density of the liquid in the pipeline to be inspected, and is adapted to roll along the bottom of the pipeline to be inspected.</p> |
