Methods and apparatuses for determining entrained and/or dissolved gas
content of gas-liquid mixtures. Data generated is used to control the True
(air-free) or Apparent (air-containing) Density or Entrained Air content
of liquids within optimum ranges, e.g. in paper coating processes and in
the manufacture of food products, personal care products, pharmaceutical
products, paints, petroleum blends, etc. For example, an indirect method
of continuously determining the amount of gas entrained in a liquid, by:
continuously measuring the temperature, flow rate, and apparent density of
the mixture at two different pressure states, and calculating the volume
percentage of the gas in the liquid by using equation (28)
##EQU1##
wherein V is the volume of the gas-free liquid calculated by equation (23)
##EQU2##
in which P.sub.1 and P.sub.2 are two different ambient pressures and
.DELTA.P=P.sub.2 -P.sub.1, .rho..sub.1 and .rho..sub.2 are apparent
densities of the liquid sample measured at P.sub.1 and P.sub.2,
respectively, R is the constant of the Ideal Gas Law, T is the liquid
temperature, Q is the flow rate, g(.DELTA.P/Q.sup.a) is a function for
determining the amount of gas being dissolved between P.sub.2 and P.sub.1,
and V.sub.s is determined by equation (27)
##EQU3##
