Multi-lamination

Figure 4.23 Near-ideal multi-lamination flow patterns in the second-generation caterpillar mini mixer as a result of introducing a splitting plate and improving micro structure geometry [50],...

This plate cuts the flow into pieces which are better defined than the poorly defined ones obtained by the first-generation caterpillar mini mixer. In addition, the micro structure geometry was improved by means of simulation. As a result, near-ideal multi-lamination flow patterns were yielded (Figure 4.23), which showed excellent correspondence with simulation [50]. 

Separation layer mixers use either a miscible or non-miscible layer between the reacting solutions, in the first case most often identical with the solvent used [48]. By this measure, mixing is postponed to a further stage of process equipment. Accordingly, reactants are only fed to the reaction device, but in a defined, e.g. multi-lamination-pattem like, fluid-compartment architecture. A separation layer technique inevitably demands micro mixers, as it is only feasible in a laminar flow regime, otherwise turbulent convective flow will result in plugging close to the entrance of the mixer chamber. 

P 27] Diazotation was performed in batchwise manner [55]. A CPC micro reactor with multi-lamination mixer (lamellae < 100 pm) was embedded in a housing... 

Micro mixers permit mixing times much below 1 s. Some multi-lamination micro mixers even approach sub-millisecond mixing [40]. Therefore, mixing can performed faster than most knovm reactions, including fast radical polymerizations. 

It is customary, mainly owing to fabrication needs, that for biological applications chip-like systems with two-layer construction are used, thus being in-plane. Mixers used for the same purposes have to adjust to this fact. Since multi-lamination typically needs several layers to achieve the proper feeding pathways, other mixers with simpler designs such as the electrokinetic instability mixer need to be applied [25], In contrast, chemical applications, where the mixer is only associated with part of the plant and not integrated in a small, flat device, do not pose such preferences indeed, multi-layer microfabrication architectures have been used. 

Bifurcation Multi-laminating Diffusive Mixing Most Relevant Citations... 

Mixer 35 [M 35] Bifurcation Multi-laminating Micro Mixer... 

Mixer type Bifurcation multi-laminating micro mixer Channel width 49-58 pm... 

Interdigital Multi-laminating Diffusive Mixing (Normal and Focusing)... 

When the multi-lamellae pattern is vertical to the feed reservoir layers, this is named vertical multi-laminating. When both are oriented in the same way, this is the horizontal variant... 

In a vertically multi-laminating variant of the interdigital principle, the two arrays of the multiple sub-streams, belonging to two fluids, are overlaid in such a way that the above-mentioned alternate arrangement results (see Figure 1.75) [34, 67]. This usually requires the reservoirs to be placed in two different layers of the microstructured device. The sub-stream channels typically start in the two different layers and merge in a common layer. 

Figure 1.75 Vertically multi-laminated interdigital feeds.

Considering the width of typical interdigital outlets, which are of the order of several tens of microns, it stands to reason that multi-lamination on its own is a rather slow mixing process, typically needing liquid mixing times of the order of seconds (see Figure 1.76 and, e.g., [34]). 

Mixer 36 [M 36] Unfocused Interdigital Multi-laminating Micro Mixer with Co-flow Injection Scheme (I), Rectangular Mixer ... 

Mixer type Interdigital vertically multi-laminating micro mixer with co-flow injection scheme Feed channel width, depth, length for liquid 2 10 pm, 5 pm, 0.335 mm... 

Figure 1.81 Two different horizontally multi-laminating mixers with different co-flow schemes curved-channel design (P-type, left), straight-channel design (middle). In addition, a part of a V-type mixer with minimized dead volume is shown [Pfeifer et at, Chem. Ing. Tech. 76, 5 (2004) 607],...

Mixer 41 [M 41] Interdigital Vertically Multi-laminating Micro Mixer with Counter-flow Injection Scheme, 10-fold Array... 

Mixer type Interdigital vertically multi-laminating micro mixer with counter-flow injection scheme, 10-fold array Number of micro channels for one feed and one element (two versions) 15,18... 

Mixer type Interdigital vertically multi-laminating micro mixer with triangular focusing Number of micro channels 2x15... 

The steel version comprises a two-piece housing, on request with an inspection window. Thin-wire erosion is used for microfabrication of the tiny cogs which served as inlet structures to achieve the multi-lamination (see Figure 1.87). High-speed... 

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