In flow chemistry, also called reactor engineering, a chemical reaction is run in a continuously flowing stream rather than in batch production.  In other words, pumps move fluid into a reactor, and where tubes join one another, the fluids contact one another.  If these fluids are reactive, a reaction takes place.  Flow chemistry is a well-established technique for use at a large scale when manufacturing large quantities of a given material.  However, the term has only been coined recently for its application on a laboratory scale by chemists and describes small pilot plants, and lab-scale continuous plants. Often, microreactors are used.