Guard Flows

Microfluidic Devices for Combinatorial Chemistry, Fig. 19 The pressure-driven flows in the valve configuration C shown in Fig. 18. Left in the OPEN state. The relocated supply channel mouth produces the desired guard flow, a small sacrificial flow into the vent... 

Small fluid flows used in the no-moving-part fluidic and microfluidic valves to ensure no cross-contamination takes place between various fluids leaving the valves into a common vent space. Guard flows are used especially in the... 

Guard Flows and Auxiliary Small Cleaning Flows... 

At low Re there is no point in using flow interaction elements. Instead, all the vent terminals V on the one hand and all the output terminals Y in the unit on the other hand are usually simply mutually connected. The driving pressure difference APyv is acting simultaneously in all the valves. It acts also in those valves which are in the closed state. To obtain in the open state the small desirable spillover guard flow into the vent terminal V requires just a careful adjustment of the driving pressure. In contrast, in the closed state, it is difficult to generate the desirable... 

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