Ultrasonic-densiometer mass flow sensor for use in flow metering units

摘要

A fuel delivery system uses a volumetric flow sensor (18) and a densiometer (30) to measure a mass flow rate of the fuel. A densiometer (30) may be a coriolis mass flow sensor etched into a small circuit chip (48). As fuel flows past the densiometer (30) a density of the fuel and characteristic slope as a function of temperature is determined. At least one temperature sensor (50) is also located on the circuit chip (48) to provide accurate temperature of the fuel to correspond to the fuel density reading. Piezoelectric crystals (38) in the volumetric flow sensor (18) generate and receive a sound wave. By analyzing the sound wave signals the volumetric flow rate of fluid through the volumetric flow sensor (18) can be calculated. At least one temperature sensor (42) is also placed on the volumetric flow sensor (18) to correct for any thermal expansion of an inner diameter of the volumetric flow sensor (18) and for final mass flow calculation. The density and temperature information from the densiometer (30) and the volumetric flow and temperature information from the volumetric flow sensor (18) are used to determine the density of the fuel at the volumetric flow sensor (18). By using the density calculated at the volumetric flow sensor (18) and using the volumetric flow information an accurate mass flow rate of the fuel at the volumetric flow sensor (18) can be calculated.