Method and apparatus for determining the mass flow of a fluid

A method of determining the mass flow of a fluid comprising measuring, at two different times, a plurality of parameters comprising the pressure P, the temperature T and the density .rho. of the fluid, determining the specific gravity G of the fluid from said plurality of parameters at each of said times, and using the measured density together with a further parameter which varies with the volumetric flow to evaluate the mass flow of the fluid only if the rate of change of G with time is within a given range of values.

Apparatus for determining the mass flow of a fluid comprising means for measuring, at each of a plurality of different regions in the fluid, a plurality of parameters comprising the pressure P, the temperature T, and the density .rho. of the fluid;

• means for determining the specific gravity of the fluid from said parameters;
• means for producing a further parameter which varies with the volumetric flow of said fluid;
• and means to evaluate the mass flow of the fluid from the values of .rho. and of said further parameter, the last-mentioned means being rendered operative only if the so-determined values of G at said regions are within a given range of values.

Apparatus for determining the mass flow of a fluid comprising means for measuring, at two different times, a plurality of parameters comprising the pressure P, the temperature T, and the density .rho. of the fluid;

• means for determining the specific gravity of the fluid from said parameters at each of said times;
• means for producing a further parameter which varies with the volumetric flow of said fluid;
• and means to evaluate the mass flow of the fluid from the values of .rho. and of said further parameter, the last-mentioned means being rendered operative only if the rate of change of G with time is within a given range of values.