Editing Pump (section)

======'''Progressing cavity pump'''======
{{Main article|Progressing cavity pump}}

[[File:Progressive_cavity_pump_animation.gif|thumb|right|Progressing cavity pump]]

Widely used for pumping difficult materials, such as sewage sludge contaminated with large particles, a progressing cavity pump consists of a helical rotor, about ten times as long as its width, and a stator, mainly made out of rubber. This can be visualized as a central core of diameter ''x'' with, typically, a curved spiral wound around of thickness half ''x'', though in reality it is manufactured in a single lobe.  This shaft fits inside a heavy-duty rubber sleeve or stator, of wall thickness also typically ''x''. As the shaft rotates inside the stator, the rotor gradually forces fluid up the rubber cavity.  Such pumps can develop very high pressure at low volumes at a rate of 90 PSI per stage on water for standard configurations.
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