A pump is a device used to move gases, liquids or slurries. A pump moves liquids or gases from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system (such as a water system). A gas pump is generally called a compressor, except in very low pressure-rise applications, such as in heating, ventilating, and air-conditioning, where the operative equipment consists of fans or blowers.
Pumps work by using mechanical forces to push the material, either by physically lifting, or by the force of compression.
The earliest type of pump was the Archimedes screw, first used by Sennacherib, King of Assyria, for the water systems at the Hanging Gardens of Babylon and Nineveh in the 7th century BC, and later described in more detail by Archimedes in the 3rd century BC. In the 13th century AD, al-Jazari described and illustrated different types of pumps, including a reciprocating pump, double-action pump, suction pump, and piston pump.
A positive displacement pump causes a fluid to move by trapping a fixed amount of it then forcing (displacing) that trapped volume into the discharge pipe. The periodic fluid displacement results in a direct increase in pressure. A positive displacement pump can be further classified as either
Pumps are used throughout society for a variety of purposes. Early applications includes the use of the windmill or watermill to pump water. Today, the pump is used for irrigation, water supply, gasoline supply, air conditioning systems, refrigeration (usually called a compressor), chemical movement, sewage movement, flood control, marine services, etc.
Because of the wide variety of applications, pumps have a plethora of shapes and sizes: from very large to very small, from handling gas to handling liquid, from high pressure to low pressure, and from high volume to low volume.
Liquid and slurry pumps can lose prime and this will require you to prime the pump by adding liquid to the pump and inlet pipes to get the pump started.
One sort of pump once common worldwide was a hand-powered water pump over a water well where people could work it to extract water, before most houses had individual water supplies.
From this came the expression "parish pump" for "the sort of matter chattered about by people when they meet when they go to get water", "matter of only local interest".
Today, hand operated village pumps are considered the most sustainable low cost option for safe water supply in resource poor settings, often in rural areas in developing countries. A hand pump opens access to deeper groundwater that is often not polluted and also improves the safety of a well by protecting the water source from contaminated buckets. Pumps like the Afridev pump are designed to be cheap to build and install, and easy to maintain with simple parts. It was assumed that spare parts would become available in the local market by for-profit wholesalers. However, it became clear with time that often spare parts are not available locally, because of the low profit margins for wholesalers, especially in Africa. This means that communities are often stuck without spares and cannot use their handpump anymore and have to go back to traditional and sometimes distant, polluted resources. This is unfortunate, as water projects often have put in a lot of resources to provide that community with a handpump. As a result, spare parts free handpumps are now being developed, like the Afripump.
Pumps have been powered by water flow (as with the noria), an internal combustion engine, electric motor, manually (as with the hand pump used for pumping groundwater, called walking beam pump), or by wind power (common for irrigation). Solar power has been used to power an electric motor, for remote locations.