Vacuum pumps operate by displacing air, creating an area of low-pressure or partial vacuum within a sealed container. Different types of vacuum pumps include the compressed-air vacuum pump and the mechanical pump, although both pumps are used to create a partial or high-vacuum within a sealed internal environment.
Vacuum pumps require a power source in order to operate, which can include an electrical motor, hand-driven piston or a reservoir of compressed air. When operated, pumps draw air from within a closed container and expel it into the atmosphere. As air pressure within the container begins to drop, a partial vacuum forms. While gas within the container cannot be expelled completely, the most effective pumps are able to achieve air pressure that is billions of times lower than the surrounding atmosphere.
The first piston-type vacuum pump was created in the mid-17th century by a German inventor named Otto von Guericke. This pump was used to create a partial vacuum by removing water from a sealed cask. Modern vacuum pumps are used for scientific research, metal refining and the drying of materials. The type of pump used is determined by the density and type of gas that needs to be removed and the degree of vacuum that needs to be created.