Vacuum plays a vital role in pumps and is essential to the pumping process. Pumps are devices used to move liquids or gases from a place of lower pressure to an area of higher pressure.
This is done by the pump applying energy to work on the fluid being pumped. Vacuum is a condition in which the pressure is lower than the atmospheric pressure in the environment. In many pumps, especially vacuum pumps, negative pressure is created to move gases or liquids from a higher pressure location to a lower pressure area. The differences in pressure between the inlet and outlet of the pump create the flow required to move the medium.