pump (redirected from Walking beam pump)

pump, device to lift, transfer, or increase the pressure of a fluid (gas or liquid) or to create a vacuum in an enclosed space by the removal of a gas (see vacuum pumps under vacuum). The centrifugal pump, the most common kind, consists basically of a rotating device, called an impeller, inside a casing. The fluid to be pumped enters the casing near the shaft of the impeller. Vanes attached to the spinning impeller give the fluid a high velocity so that it can move through an outlet. The reciprocating pump moves a fluid by using a piston that travels back and forth in a cylinder with valves to help control the flow direction. Examples are the lift pump and the force pump. In a lift pump the piston and cylinder are positioned vertically. When the piston moves upward, atmospheric pressure pushes water into the cylinder to fill the empty space beneath the piston. On the downward stroke, the water in the cylinder is forced to flow above the piston. Reversing direction, the piston moves up, allowing more water to come up under it into the cylinder and lifting the water held above it to an outlet pipe where the water flows out of the pump. Since atmospheric pressure will support a column of water no higher than about 33 ft (10 m), a lift pump can raise water no farther than this distance. The rotary pump is like the reciprocating pump in that it allows a fluid to fill a space that then decreases in volume, forcing the fluid out of the space. However, unlike a reciprocating pump, it has no valves and uses one or more rotating components in place of a piston. The jet pump has no moving parts; it uses a swiftly moving fluid to induce motion in another fluid. For example an atomizer, a type of jet pump, uses a high-speed stream of air to pump a liquid, such as a perfume. Compressors are used to pump air or other gases into a closed container. They range from hand pumps to large power-driven devices that furnish compressed air for operating pneumatic machinery and for various other purposes. In nuclear reactors that use liquid radioactive metal, the nonmechanical electromagnetic pump is employed. An electric current is either induced in the liquid metal or is passed through it by electrodes. A magnetic field surrounding the pipe then propels the current-carrying liquid forward.

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pump

Machine that uses energy to raise, transport, or compress fluids. Pumps are classified by how they transfer energy to the fluid. The basic methods are volume displacement, addition of kinetic energy, and use of electromagnetic force. Pumps in which displacement is accomplished mechanically are called positive displacement pumps. Kinetic pumps pass kinetic energy to the fluid by means of a rapidly rotating impeller (blade). To use electromagnetic force, the fluid being pumped must be a good electrical conductor. Pumps used to transport or pressurize gases are called compressors, blowers, or fans.

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pump

1. any device for compressing, driving, raising, or reducing the pressure of a fluid, esp by means of a piston or set of rotating impellers

2. Biology a mechanism for the active transport of ions, such as protons, calcium ions, and sodium ions, across cell membranes

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pump [pəmp]

(electronics)

Of a parametric device, the source of alternating-current power which causes the nonlinear reactor to behave as a time-varying reactance.

(mechanical engineering)

A machine that draws a fluid into itself through an entrance port and forces the fluid out through an exhaust port.

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Pump

A machine that draws a fluid into itself through an entrance port and forces the fluid out through an exhaust port (see illustration). A pump may serve to move liquid, as in a cross-country pipeline; to lift liquid, as from a well or to the top of a tall building; or to put fluid under pressure, as in a hydraulic brake. These applications depend predominantly upon the discharge characteristic of the pump. A pump may also serve to empty a container, as in a vacuum pump or a sump pump, in which case the application depends primarily on its intake characteristic. See Centrifugal pump, Compressor, Displacement pump, Fan, Fuel pump, Pumping machinery, Vacuum pump