| 摘要 |
<p>In filling a tank, e.g. of a lorry or wagon, with a liquid, particularly a hydrocarbon, by lowering a pipe under the control of a double acting hydraulic jack into the tank to the bottom and then supplying the liquid to the pipe, the volume of hydraulic fluid flowing to the jack is measured during lowering movement of the pipe, the measurement is converted into a signal representing the position of the end of the pipe and the signal is compared with a reference signal representing the position of the bottom of the tank, so that the operator can check whether the pipe has reached the bottom of the tank.</p> |
