Method and system for measurement of a liquid level in a tank

摘要

A system for dispatching a refilling vehicle to a tank updates a prior collected average level of substance in the tank. It continuously determines values of differential pressure within the tank and in accordance with the values of differential pressure, calculates the instantaneous level of substance within the tank. A prior collected average level is stored and is compared with each of the instantaneous values of level thus obtained. On the basis of this comparison a relative weighting factor is determined which weighs the relative contribution of the collected and instantaneous values in determining a new collected value. In one embodiment a remote location may interrogate to determine the rate of usage over a predetermined time window. In another embodiment when the new collected average falls below a set point a selected one of a plurality of remote locations is signalled to dispatch a refilling vehicle. A remote location may be selected in accordance with the time of day or the substance in the tank. The time window, the set points and selection of a remote location may all be programmed from a remote location.