Method and apparatus for the measurement of the mass flow rates of fluid components in a multiphase slug flow

An apparatus for measuring mass flow rates of liquid phases in a multiphase slug flow containing at least two liquid phases, said apparatus comprising:

• (i) a tube through which a flow passes;
• (ii) first means for detecting commencement of passage of a slug in the flow past a first location in said tube;
• (iii) transmission measuring means for measuring mass or volume fractions of the liquid phases by transmitting energy through the flow at the first location;
• (iv) second means for detecting ending of the passage of a slug past the first location;
• and
• (v) calculating means responsive to said first, second, and transmission measuring means for determining mass flow rate of the liquid phases through said tube from (a) measuring total mass or volume of liquid flowing through said tube and (b) measuring mass or flow fractions by said transmission measuring means, only between detection of the commencement and the ending of passage of respective slugs in the flow.