Patent ID: 7317993
Filing Date: 2008-01-08
Classification: G01F

Abstract:
1. A detector for determining when a fluid level has dropped below a prespecified level, the detector comprising: a probe placed in a fluid containment vessel; a signal generator for generating a transmitted signal, said transmitted signal passing into a fluid within said fluid containment vessel; and a processor; wherein said processor obtains a received signal detected by said probe; wherein said processor stores said received signal associated with a time segment; wherein said processor obtains and stores signals for a plurality of time segments within a time period; wherein said processor determines a representative probe signal for said time period; wherein said processor determines a dynamic indicator for said probe signals in said period, said dynamic indicator is any indicator showing the divergence or variability of the individual signal levels associated with the time segments in the period compared to the baseline value; and wherein said processor uses both said representative probe signal and said dynamic indicator to determine if said probe is within said fluid.