A submersible pump is a pump which has a hermetically sealed motor close-coupled to the pump body. For information on Wikipedia project-related discussions see WikipediaVillage pump. A hermetic seal is a seal which for practical purposes is considered airtight An electric motor uses Electrical energy to produce Mechanical energy. The whole assembly is submerged in the fluid to be pumped. The advantage of this type of pump is that it can provide a significant lifting force as it does not rely on external air pressure to lift the fluid.

Working principle

ESP systems are effective for pumping produced fluids to surface.

A system of mechanical seals are used to prevent the fluid being pumped from entering the motor and causing a short circuit. A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage (e Short Circuit is a 1986 comedy Science fiction film starring Ally Sheedy and Steve Guttenberg and directed by The pump can either be connected to a pipe, flexible hose or lowered down guide rails or wires so that the pump sits on a "ducks foot" coupling, thereby connecting it to the delivery pipework.

Applications

Submersible pumps are found in many applications, single stage pumps are used for drainage, sewage pumping, general industrial pumping and slurry pumping. They are also popular with aquarium filters. Multiple stage submersible pumps are typically lowered down a borehole and used for water abstraction or in water wells. A borehole is the generalised term for any narrow shaft drilled in the ground either vertically or horizontally Water abstraction, or water extraction, is the process of taking Water from any source either temporarily or permanently

ESP usage in oil wells

Submersible pumps are also used in oil wells. West Texas PumpjackJPG|thumb|right|300px|This Pumpjack located south of Midland TX is a common sight in West Texas. By decreasing the pressure at the bottom of the well (by lowering bottomhole flowing pressure, or increasing drawdown), significantly more oil can be produced from the well compared to natural production. This makes Electric Submersible Pumping (ESP) a form of "artificial lift" (as opposed to natural flow) along with Gas Lift, Beam Pumping, Plunger Lift and Progressive cavity pump. Gas lift is one of a number of processes used to artificially lift oil or water from wells where there is insufficient reservoir pressure to produce the well “Nodding donkey” redirects here For the train see British Rail "Pacer". A progressive cavity pump is also known as a progressing cavity pump, eccentric screw pump or even just cavity pump and as is common in engineering generally New varieties of ESP can include a water/oil separator which permits the water to be reinjected into the reservoir without the need to lift it to the surface.

The ESP system consists of a number of components that turn a staged series of centrifugal pumps to increase the pressure of the well fluid and push it to the surface. The energy to turn the pump comes from a high-voltage (3 to 5 kV) alternating-current source to drive a special motor that can work at high temperatures of up to 300 °F (150 °C) and high pressures of up to 5000 lb/in² (34 MPa), from deep wells of up to 12000 feet (3. 7 km) deep with high energy requirements of up to about 1000 horsepower (750 kW). ESPs have dramatically lower efficiencies with significant fractions of gas, greater than about 10% volume at the pump intake. Given their high rotational speed of up to 4000 rpm (67 Hz) and tight clearances, they are not very tolerant of solids such as sand.

Special attention to the type of ESP is required when using certain types of liquids. ESP's commonly used on board naval vessels cannot be used to dewater contaminated flooded spaces. These use a 440 volt A/C motor that operates a small centrifugal pump. It can also be used out of the water, taking suction with a 2-1/2 inch non-collapsible hose. The pumped liquid is circulated around the motor for cooling purposes. There is a possibility that the gasoline will leak into the pump causing a fire or destroying the pump, so hot water and flammable liquids should be avoided.

See also

• Oil well
• Centrifugal pump