Coriolis Micro Flow Sensor

Introduction

Accurate mass flow sensing is of the utmost importance for a vast number of micro-fluidic applications, such as DNA or chemical analysis devices. Using a Coriolis force-based sensor, a number of problems can be overcome in comparison to other flow sensor devices. The main advantages of a Coriolis-based sensor are that it is independent of:

The main principle of a Coriolis sensor can be seen in figure 1:

If there is a mass flow in the given direction, the Coriolis force causes the U-shaped loop which is vibrated with a frequency ω to deform over the angle θ_c. The force (and hence the deformation) is directly proportional to the mass flow rate:

Demands on the sensor

This results in the following estimate for an U-shaped tube:

total length of tube: 10 mm

diameter of tube: 40 µm

Mode of operation

The sensor can be operated in two modes: the “swing” and the “torsion” mode. When operated in Swing mode, the Coriolis force gives rise to a torsional mode (which is measured), and vice versa:

Fabrication process of SiRN tubes

First results