Flow meters; water meters; multivariable flow meter; water sensors for measuring water pressure, volumetric flow rate, mass flow rate, fluid density, vortex, gas mixtures, and quality; diagnostic apparatus for use in flow meters for water pressure, volumetric flow rate, mass flow rate, fluid density, vortex, gas mixtures, and quality; Scientific apparatus for use with water meters, flow meters and water sensors, namely, downloadable or recorded software for monitoring and verifying performanc...