Automatic shut down for high pot temperature to prevent the still bottoms from continuing to cook after all solvent has boiled off. Automatic shut down for high condenser-water temperature to prevent solvent vapors from being lost due to malfunctions that cause low or no coolant flow. A relief valve for pressure buildup. Controls that are explosion-proof, intrinsically safe or installed in a remote location if flammable solvents are processed. Interlock features that prevent opening of the still until it has cooled to a certain temperature.
Water is generally the simplest and least costly cooling medium.
Air cooling can make sense in some cases, such as for very small units, but electric fan motors are generally not explosion-proof and their use should be carefully evaluated. Refrigerated chillers are expensive. Nitrocellulose is explosive when dry. Special precautions are required to distill materials containing nitrocellulose. Automotive lacquers, and flexographic and gravure inks can contain nitrocellulose.