See Surface Pump. Water is pushed out by centrifugal force. See also multi-stage. Check Valve - A valve that allows water to flow one way but not the other. Diaphragm Pump - A type of pump in which water is drawn in and forced out of one or more chambers, by a flexible diaphragm.
Check valves let water into and out of each chamber.
Foot Valve - A check valve placed in the water source below a surface pump. See check valve and priming. Positive Displacement Pump - Any mechanism that seals water in a chamber, then forces it out by reducing the volume of the chamber. Used for low volume and high lift. Conventional AC deep well submersible pumps and higher power solar submersibles work this way.