In the majority of industrial chemical process, a reactor is the key item of equipment in whichraw materials undergo a chemical change to form desired product. The design and operationof chemical reactors is thus crucial to the whole success of the industrial operation.Reactors can widely form, depending on the nature of the feed materials and the products. Understanding non-steady behavior of process equipment is necessary for design and operation of automatic control systems. One particular type of process equipment is the continuous stirred tank reactor. In this reactor, it is important to determine the system response to a change in concentration. This response of concentration versus time is an indication of the ideality of the system. The Armfield Stirred Tank Reactors in Series unit is designed to follow the dynamics of the perfectly mixed multi-stage process. Dynamic behaviour can be studied as can multi-stage chemical reaction. Bench mounted and self-contained, the unit requires only to be connected to a single phase electrical supply for operation. A self-contained bench mounted small scale unit fitted with three continuous stirred reactors in series which are fed from two 5 litre tanks. Each reactor is fitted with a conductivity probe.There are three reactor vessels connected in series, each containing a propellor agitator driven by a variable speed electric motor. Two reagent vessels and two variable speed feed pumps feed reagents into the first reactor in line. For certain experiments the feed can be connected to the third reactor and a dead-time coil, also positioned on the vacuum formed plinth. Each reactor and the exit port of the dead-time coil are fitted with accurate conductivity probes for monitoring the process. Conductivity is displayed on a digital meter on the console through a selector switch and all four probes can be connected to the optional Armfield data logging accessory CEX-304IFD. A dead-time residence coil can also be attached to the exit of the last reactor in the series