Abstract: A microfluidic device includes a thermal buffer fluid passage and a reactant passage having mixing and dwell time sub-passages all defined within an extended body, the dwell-time sub-passage having at least 1 ml volume, and the mixing sub-passage being in the form of a unitary mixer not requiring precise splitting of flows to provide good mixing. The device is desirably formed in glass or glass-ceramic. The unitary mixer is structured to generate secondary flows in the reactant fluid and is preferably closely thermally coupled to the buffer fluid passage by sharing one or more common walls.

Abstract: A class of designs is provided for a mixer in micro reactors where the design principle includes at least one injection zone in a continuous flow path where at least two fluids achieve initial upstream contact and an effective mixing zone (i.e. adequate flow of fluids and optimal pressure drop) containing a series of mixer elements in the path. Each mixer element is preferably designed with a chamber at each end in which an obstacle is placed (thereby reducing the typical inner dimension of the chamber) and with optional restrictions in the channel segments. The obstacles are preferably cylindrical pillars but can have any geometry within a range of dimensions and may be in series or parallel along the flow path to provide the desired flow-rate, mixing and pressure-drop. The injection zone may have two or more interfaces and may include one or more cores to control fluids before mixing.