METHOD AND APPARATUS FOR MEASURING THE CONTENT OF A STORAGE VESSEL

摘要

The peak amplitude values of two different frequency pressure changes produced by the displacement device of a volume sensing arrangement, are obtained and one divided by the other to produce a value indicative of the volume of the unfilled portion of a storage vessel. The contents of the vessel are derived by subtracting the unfilled volume from the vessel capacity. In the embodiments a single pressure sensor is used, the signal is simultaneously filtered with a low pass filter and a band pass filter in order to obtain static and dynamic pressure data. In some embodiments the single sensor is disposed in a chamber in which the displacement means produces two different frequency pressure variations. The chamber is communicated with th storage vessel by a pipe the length and diameter of which are selected to prevent the pressure variations produced by one of the frequencies from being transmitted therethrough. In other embodiments two pressure sensors are used and the special pipe dispensed with and the outputs of the two sensors fed to band pass filters.