A pumps main function is to bring water from a well or lake to an irrigation system. Pumps can be used to increase water pressure when the provided pressure isn't high enough. Pumps are generally used in systems that have elevation extremes and systems that are located in areas that provide water at low pressures. A pump is made up of blades or impellers inside a housing or case.
A pump draws and expels water using its intake and discharge line. A shaft connects the motor to the pump blades or impellor. The motor turns the impellor creating a vacuum or low pressure zone. A vacuum is achieved when there is zero pressure. Most pumps don't create a true vacuum, but create a zone with pressure that is lower than air pressure. Once the low pressure zone is created the water is pushed by air pressure from the well or lake up to the pump. When the water reaches the inside of the pump the impellers throw the water to the outside of the impeller case causing a centrifugal action. This action allows the water to be pumped or pushed to the irrigation heads. A pump must run before the system is activated and at all times when the irrigation system is functioning.