A flow meter suitable for the measurement of the mass flow rate of two phase flows. The flow meter has an S-shaped flow tube located within a housing. The housing has an inlet and outlet which are in register with the inlet and outlet of the flow tube. The flow tube has force transducers fitted at the bends of the tube which measure the reaction forces during fluid flow and enable a mass flow reading to be obtained.

http://www.freepatentsonline.com/4677859.html