by sensing weight of individual components, e.g. gravimetric procedure

Full Title

Control of flow ratio (control of chemical or physico-chemical variables, e.g. pH-value, G05D21/00; control of humidity G05D22/00; control of temperature by varying the mixing ratio of two fluids having different temperatures G05D23/13; control of viscosity G05D24/00) > Controlling ratio of two or more flows of fluid or fluent material > with auxiliary non-electric power > by sensing weight of individual components, e.g. gravimetric procedure