MICRO MIXER

Abstract: In this study the development of a continuous radical solution polymerization process for acrylates in a lab scale tube reactor was performed. Fouling in the reactor was always observed if there were bad mixing conditions at the feed point of the reactor. In order to increase the homogenization of monomer and initiator a micro mixer was installed at the reactor inlet. The micro mixer ensured a very fast mixing at the micro scale of the preheated monomer and initiator solutions, and fouling was reduced tremendously.

Abstract: We report successful design, fabrication and testing of a novel lamination micro mixer to be integrated in the micro-scale immunomagnetic cell sorter (µ-IMCS), which should be a key device for clinical applications of regenerative medicine. This paper covers, (i) the concept of µ-IMCS, (ii) design and fabrication of lamination mixer using MEMS technologies, (iii) numerical analysis for the evaluation of the mixer performance, and (iv) experimental evaluation of target cell capturing with the present micro mixer. In order to reduce the sedimentation loss of the cells and the magnetic beads, the conduits in the mixer are designed in such a way that the stream is turned over 180degree. It is found in the CFD analysis that the present lamination mixer realizes better mixing and lower sedimentation loss than the one without rotation in the previous study. Experiments reveal that the cell capture rate is (i) increased by up to 8.6 times compared with that in a straight channel, and (ii) decreased with decreasing the residence time. It is also demonstrated in a preliminary experiment that CD31 expressions of HUVEC and hMSC obtained with the present micro mixer are in good agreement with the data obtained with a conventional cell sorting system. Therefore, the present mixer should be a viable component in a µ-IMCS.

Abstract: PROBLEM TO BE SOLVED: To provide a micro mixer with a simple configuration and a fluid mixing method using the mixer. SOLUTION: The micro mixer 100 comprises a fluid flow pipe 10 which forms a plurality of fluid channels 11 expended in parallel to each other in the inside along the longitudinal direction and a fluid mixing part 20 which is installed continuously in the fluid flow-out side of the fluid flow pipe 10, forms a fluid stagnation region 21 for stagnating a plurality of fluids flowing out of the fluid flow pipe 10 in a state the fluids are mixed, and has mixing fine pores for for passing, stratifying and mixing a plurality of the fluids. COPYRIGHT: (C)2007,JPO&INPIT

Abstract: Electrochemical micromachining (ECMM) is an advanced machining process for machining of electrically conducting materials. In the present work, a micro nozzle and a fluidic mixer having complex structures are made using masking technique by ECMM process. Mask is made of 50-μm transparent sheet and the micro nozzle and micro mixer are fabricated on an 800-μm thick copper sheet. The resulting rough inner walls and bottom surface of micro nozzle are finished using magnetorheological fluid-based finishing process. Surface finish of the nozzle is significantly improved after finishing. A comparison of width, depth, and surface roughness of the micro nozzle is also carried out before and after finishing. The mixing behavior of two fluids is visualized by microscope in micro mixer. The rough inner walls of the mixer’s channels act as obstructions and result in zigzag path of flowing fluid. Hence, mixing occurs at microscopic level because of rapid molecular diffusion.