110 毛細管差圧式微小流量計の開発(S33-2 様々なマイクロ流動現象,S33 マイクロ・ナノフルイディクス)  [in Japanese] 110 Development of Micro Flow Meter Based on Pressure Deference in Capillary  [in Japanese]

A new micro flow meter consisting of a capillary and pressure gauge has been developed. As the flow rate in the capillary obeys the Hagen-Poiseuille equation, the flow rate can be determined by measurement of the pressure difference between the entrance and exit of the capillary. An experimental study is performed to develop the measurement technique for a micro-scale pressure difference and the measurement error is discussed. The following results are derived from the experiments: When the flow rate changes suddenly as a step function, the pressure gauge output takes 10sec to follow the pressure difference change. In case of the flow meter using a capillary with 0.46mm diameter and 60mm length, the steady pressure difference gives the flow rate of 50 nl/s with an accuracy of ±3%. For the case of the flow rate over 50 nl/s, the measured pressure difference consists with the theoretical value with an accuracy of ±0.6%. On the other hand, the error between measured pressure difference and theoretical one becomes large for the flow rate under 50 nl/s.