Many industrial, commercial and consumer processes involve the injection of a gas into a liquid. Intimate contact of the gas and liquid is generally beneficial to the process, and the degree to which this can be achieved will depend on the system's ability to overcome the tendency of the gas to separate from the liquid and coalesce into large bubbles or pockets. Intimate contact, i.e., an increase in the interfacial area can be achieved in a variety of ways, such as the use of specially designed nozzles for the injection of the gas, the use of propellers or stirrers for mechanized mixing, or the insertion of specially engineered conduit sections which function as static mixers.
While any of these methods will suffice to shear gas into small bubbles, certain effects are preferably avoided. Pressure drops, such as those inherent in nozzles, should be avoided or minimized since they consume energy and impede flow. Clogging or fouling of flow passages should also be avoided, since this can cause a rapid rise in the pressure drop if not stop up the flow completely. Still further, the possibility of corrosion must be considered, particularly when this results in frequent or time-consuming down-time for disassembly and replacement of parts.