For engineers designing pressurized air or vacuum systems, it’s important to understand that no single air-pressure or vacuum technology is optimal for all applications, as illustrated by the comparisons shown in Fig. 1 and Fig. 2. To help narrow down the choices, engineers can peruse charts for flow, pressure, and vacuum that are widely available from pump manufacturers. Before starting the process, however, it is helpful to be acquainted with the chief characteristics of the most common pump technologies used by equipment designers.