A vacuum pump is a device that draws gas molecules from a sealed volume in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity. Vacuum pumps are categorized by their operating pressure range and as such are classified as primary pumps, booster pumps or secondary pumps. Within each pressure range are several different pump types, each employing a different technology, and each with some unique advantages in regard to pressure capacity, flow rate, cost and maintenance requirements. Regardless of their design, the basic principle of operation is the same. The vacuum pump functions by removing the molecules of air and other gases from the vacuum chamber (or from the outlet side of a higher vacuum pump if connected in series). While the pressure in the chamber is reduced, removing additional molecules becomes exponentially harder to remove. As a result, an industrial vacuum system (Fig. 1) must be able to operate over a portion of an extraordinarily large pressure range, typically varying from 1 to 10-6 Torr of pressure. In research and scientific applications, this is extended to 10-9 Torr or lower. In order to accomplish this, several different styles of pumps are used in a typical system, each covering a portion of the pressure range, and operating in series at times.
Vacuum pumps are one of, if not the most important set of components supplied on vacuum furnaces. The processes we run and the quality we achieve is a function of how these systems perform. Vacuum pumps are also known as ‘suction pumps’. They are hardworking devices and it is important to ensure they are properly maintained and replaced when necessary.