Abstract: A meter for the measurement of the gas mass flow rate and total liquid mass flow rate of a two phase or multiphase fluid is disclosed. The meter comprises a series of three flow element, the firs element is arranged to mix fluids passing therethrough and the second and third elements are each arranged to provide a measurement of the differential pressure across that element. The second and third elements may be added to an existing installation with an element capable of performing mixing, after the mixing element. The second and third elements provide independent measurements by having different configurations presented to the fluids passing therethrough. The first and third elements may comprise conduits with internal projections and the second element may be a venturi. A flow element for use in such a meter is also disclosed.

Abstract: A meter for the measurement of the gas mass flow rate and total liquid mass flow rate of a two phase or multiphase fluid is disclosed. The meter comprises a series of three flow element, the firs element is arranged to mix fluids passing therethrough and the second and third elements are each arranged to provide a measurement of the differential pressure across that element. The second and third elements may be added to an existing installation with an element capable of performing mixing, after the mixing element. The second and third elements provide independent measurements by having different configurations presented to the fluids passing therethrough. The first and third elements may comprise conduits with internal projections and the second element may be a venturi. A flow element for use in such a meter is also disclosed.

Abstract: A method of measuring a gas mass fraction (X) in a mass of liquid and gas flowing in direction (A) along pipeline (2) which includes a venturi formed by throat (10), convergent portion (12) and divergent portion (14). Adjacent the venturi (12, 10, 14) but upstream is a flow conditioner (28) creating a uniform mixture of gas and liquid downstream so as to reduce or avoid slip between the gas and liquid phases in the venturi. Differential pressure (DP1) is measured between a position upstream of the flow conditioner and a position intermediate the flow conditioner and venturi. Differential pressure (DP2) is measured between the throat and a position intermediate the flow conditioner and venturi. Differential pressure (DP3) is measured across the venturi. Computer (50) calculates the gas mass fraction (X) using a formula that may take the form: X=a·(DP1)b·(DP2)c·(DP3)d·(DP2−DP3)e·(DP1+DP3)f, in which a, b, c, d, e and f are constants.