Continuous reactors are typically tube-like and manufactured from non-reactive materials such as stainless steel, glass, and polymers. Mixing methods include diffusion alone (if the diameter of the reactor is small e.g. <1 mm, such as in microreactors) and static mixers. Continuous flow reactors allow good control over reaction conditions including heat transfer, time, and mixing.
The residence time of the reagents in the reactor (i.e. the amount of time that the reaction is heated or cooled) is calculated from the volume of the reactor and the flow rate through it:
Therefore, to achieve a longer residence time, reagents can be pumped more slowly and/or a larger volume reactor used.  Production rates can vary from nanoliters to liters per minute.
Some examples of flow reactors are spinning disk reactors; spinning tube reactors; multi-cell flow reactors; oscillatory flow reactors; microreactors; hex reactors; and aspirator reactors.
In an aspirator reactor a pump propels one reagent, which causes a reactant to be sucked in. This type of reactor was patented around 1941 by the Nobel company for the production of nitroglycerin.