| An electrically driven pump is known as an | | | | large to very small, from handling gas to handling |
| electropump. | | | | liquid, from high to low pressure, and from high to |
| A pump is a mechanical device. used to move | | | | low volume. |
| fluid, such as gas, liquid or slurry. | | | | Liquid / slurry pumps can lose prime and this will |
| Pumps operate by displacing a volume by a | | | | require the pump to be primed by adding liquid to |
| physical or mechanical action. | | | | the pump and inlet pipes to get the pump started. |
| Pumps alone do not create pressure. Pumps only | | | | Loss of "prime" is due to ingestion of air into the |
| displace fluid, causing a flow. Adding resistance to | | | | pump. The clearances and displacement ratios in |
| the flow causes pressure. | | | | pumps used for liquids and other more viscus |
| Pumps fall into two main groups: positive | | | | fluids cannot displace the air due to its lower |
| displacement and rotodynamic. Their names | | | | density. |
| describe their method for moving a fluid. | | | | One sort of pump once common worldwide was |
| Pump efficiency can be defined as the ratio of | | | | a hand-powered water pump over a water well |
| the power imparted on the fluid by the pump in | | | | where people could work it to extract water, |
| relation to the power supplied to drive the pump. | | | | before communities had individual water supplies. |
| Pump efficiency is an important aspect and | | | | From this came the expression "parish pump" for |
| pumps ought to be regularly tested. | | | | "the sort of matter chattered about by people |
| Thermodynamic pump testing is one method of | | | | when they meet when they go to get water", |
| Pump efficiency testing. | | | | "matter of only local interest". However water |
| Pumps are commonly rated by the following | | | | from pitcher pumps are more prone to |
| criteria: horsepower, flow rate, outlet pressure in | | | | contamination since it is drawn directly from the |
| feet / metres of head, inlet suction in suction feet | | | | soil and thus doesn't undergo filtration, this may |
| / metres of head. The head is the number of | | | | cause gastrointestinal related diseases. |
| feet or metres the pump can raise or lower a | | | | Today, hand operated village pumps are still |
| column of water at atmospheric pressure. | | | | considered the most sustainable low cost option |
| Engineers often use a quantity termed the | | | | for safe water supply in resource poor settings, |
| 'specific speed' to identify initially the most suitable | | | | often in rural areas in developing countries. A hand |
| pump type for a particular combination of flow | | | | pump may open access to deeper groundwater |
| rate and head. | | | | that is often not polluted and also improves the |
| A Positive displacement pump causes fluid to | | | | safety of a well by protecting the water source |
| move by trapping a fixed amount of it then | | | | from contaminated buckets. Pumps like the |
| forcing (displacing) that trapped volume into the | | | | Afridev pump are designed to be cheap to build / |
| discharge pipe. A positive displacement pump can | | | | install, and easy to maintain with simple parts. |
| be further classified according to the mechanism | | | | However, scarcity of spare parts for these type |
| used to move the fluid, Rotary-type, (e.g., the | | | | of pumps in some regions of Africa may diminish |
| lobe, external gear, internal gear, screw, shuttle | | | | their use for these areas. |
| block, flexible vane or sliding vane, helical twisted | | | | Rotary-type pumps include the Gear pump, |
| roots e.g. the Wendelkolben or liquid ring vacuum | | | | Progressing cavity pump, Roots-type pumps, |
| pump) or Reciprocating-type, e.g., the piston or | | | | Peristaltic pumps |
| diaphragm pump.) | | | | Reciprocating-type pumps include the |
| Pumps are used for a variety of purposes. Early | | | | Compressed-air-powered double-diaphragm pumps |
| applications includes the use of the windmill or | | | | Rotodynamic pumps (or dynamic pumps) include |
| watermill to pump water. Today, pumps are used | | | | the centrifugal pump, Radial flow pumps, Axial |
| for irrigation, water supply, gasoline supply,air | | | | flow pumps, Mixed flow pumps and Eductor-jet |
| conditioning systems, refrigeration (usually called a | | | | pumps. |
| compressor), chemical movement,sewage | | | | Types of Multiphase Pumps include Helico-Axial |
| movement, flood control / relief, marine services, | | | | (Centrifugal), Twin Screw (Positive Displacement), |
| etc. | | | | Progressive Cavity (Positive Displacement) |
| Because of the wide variety of applications, | | | | And Electric Submersible Pumps (Centrifugal). |
| pumps have a variety of shapes and sizes: from | | | | |