Optical measurement of a Micro Coriolis mass flow sensor
Haneveld demonstrated a micro Coriolis mass flow sensor, operating in the measurement range of 0 to 1 g/hr achieving a resolution in the order of 10 mg/hr using a laser vibrometer. Equipped with an integrated capacitive  readout the measurement uncertainty amounted to 2% of the full scale range. We demonstrate a down-scalable and low-cost optical sensor system that measures the movement of the micro Coriolis mass flow tube with a high resolution. The noise level is measured to be 6 mg/hr at a 3s confidence interval.
Coriolis tube motion explanation: http://www.youtube.com/watch?v=xvcwV8Y3ALM
Coriolis tube motion explanation using shower hose: http://www.youtube.com/watch?v=6cjmFCQEMGM
Figure 1: Working principle of the micro Coriolis mass flow meter. An actuation rotational velocity ωact, in combination with a mass flow Фm yields a Coriolis force Fcor.
Figure 2: Working principle of the optical beam deflection using a laser source and a quadrant cell which resolves the spot displacement due to rotational tube deflections. The shown location of reflection shows little translation and is therefore optimal.
Figure 3: SEM picture close-up of an SiRN tube. (J. Haneveld)
Figure 4: SEM overview picture of an SiRN tube. (J. Haneveld)
For more information:
L. Kristiansen, A. Mehendale, D.M. Brouwer, J.M. Zwikker and M.E. Klein, Optical measurement of a Micro Coriolis mass flow sensor, Proc. of the EUSPEN Int. conf., San Sebastian, Spain, 2-5 June 2009, Vol.I, pp.328-332, ISBN 0-9553082-6-0
J. Haneveld, T.S.J. Lammerink, M.A. Dijkstra, H. Droogendijk, M.J. de Boer and R.J. Wiegerink, "Highly Sensitive Micro Coriolis Mass Flow Sensor," MEMS 2008, Tucson, Arizona, January 13-17, 2008.