Redirected from Pumps
The earliest pump was described by Archimedes around 300 BC and is known as the Archimedes screw pump. Pumps work by using mechanical forces to push the material, either by physically lifting, or by the force of compression.
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Types of pump Pumps fall into two categories: positive displacement pumps, which force fluid from one sealed chamber to another with little leakage, and dynamic pumps, which use the momentum of the fluid to move it across an unsealed chamber.
This type of pump forces the fluid from one chamber to another by reducing the volume of the first chamber while increasing the volume of the second. Such a pump produces a constant flow regardless of intake pressure or outlet pressure, unless the intake pressure drops below a certain limit, causing cavitation, or the outlet pressure exceeds the capacity of the pump, causing pump failure. These pumps often have a relief valve to prevent the latter problem.
Examples:
It is an example of an ejector pump. Steam ejectors are used to cool bleach water so it will retain the chlorine, which comes out at high temps. They simply discharge a boiler into a tube, sucking water vapor out from above a sealed tank. The water inside slowly cools. Not very efficient, but does something useful with waste steam, simply.
Ejectors are used to augment the flow in turbojets, near the aft end.
The Coanda effect[?] is the tendency of such a moving stream to cling to a surface, even when the surface deflects the stream away from its original direction. The surface seems to pull the stream.
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