Editing Pump (section)

===== '''Rotary positive-displacement pumps''' =====
[[File:Pompe à palettes.gif|thumb| [[Rotary vane pump]] ]]

These pumps move fluid using a rotating mechanism that creates a vacuum that captures and draws in the liquid.<ref>{{Cite news|url=http://www.pumpscout.com/articles-expert-advice/understanding-positive-displacement-pumps-aid89.html|title=Understanding positive displacement pumps {{!}} PumpScout|access-date=2018-01-03|archive-date=2018-01-04|archive-url=https://web.archive.org/web/20180104073336/http://www.pumpscout.com/articles-expert-advice/understanding-positive-displacement-pumps-aid89.html|url-status=dead}}</ref>

''Advantages:'' Rotary pumps are very efficient<ref>{{Cite web|url=https://www.pumpsandsystems.com/rotary-pumps/may-2015-volumetric-efficiency-rotary-positive-displacement-pumps|title=The Volumetric Efficiency of Rotary Positive Displacement Pumps|website=www.pumpsandsystems.com|access-date=2019-03-27|date=2015-05-21}}</ref> because they can handle highly viscous fluids with higher flow rates as viscosity increases.<ref>{{Cite web|url=http://www.lobepro.com/fund-why-choose-lobepro-12-reasons.php|title=Positive Displacement Pumps - LobePro Rotary Pumps|last=inc.|first=elyk innovation|website=www.lobepro.com|access-date=2018-01-03|archive-date=2018-01-04|archive-url=https://web.archive.org/web/20180104013854/http://www.lobepro.com/fund-why-choose-lobepro-12-reasons.php|url-status=dead}}</ref>

''Drawbacks:'' The nature of the pump requires very close clearances between the rotating pump and the outer edge, making it rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the fluids cause erosion, which eventually causes enlarged clearances that liquid can pass through, which reduces efficiency.

Rotary positive-displacement pumps fall into five main types:
* [[Gear pump]]s – a simple type of rotary pump where the liquid is pushed around a pair of gears.
* [[Screw pump]]s – the shape of the internals of this pump is usually two screws turning against each other to pump the liquid
* [[Rotary vane pump]]s
* Hollow disc pumps (also known as eccentric disc pumps or hollow rotary disc pumps), similar to [[scroll compressor]]s, these have an eccentric cylindrical rotor encased in a circular housing. As the rotor orbits, it traps fluid between the rotor and the casing, drawing the fluid through the pump. It is used for highly viscous fluids like petroleum-derived products, and it can also support high pressures of up to 290 psi.<ref>{{Cite web|url=https://www.psgdover.com/mouvex/products/eccentric-disc-pumps|title=Eccentric Disc Pumps|website=PSG}}</ref><ref>{{Cite web|url=https://www.apexequipmentltd.com/omg-pumps/hollow-disc-rotary-pumps/|title=Hollow Disc Rotary Pumps|website=APEX Equipment|access-date=2019-12-20|archive-date=2020-08-06|archive-url=https://web.archive.org/web/20200806144704/https://www.apexequipmentltd.com/omg-pumps/hollow-disc-rotary-pumps/|url-status=dead}}</ref><ref>{{Cite web|url=http://www.mpompe.com/en/principi-funzionamento.html|title=M Pompe &#124; Hollow Oscillating Disk Pumps &#124; self priming pumps &#124; reversible pumps &#124; low-speed pumps|website=www.mpompe.com|access-date=2019-12-20|archive-date=2020-02-06|archive-url=https://web.archive.org/web/20200206090355/http://www.mpompe.com/en/principi-funzionamento.html|url-status=dead}}</ref><ref>{{Cite web|url=https://www.bedu.eu/products/hollow+disc+pumps|title=Hollow disc pumps|website=Pump Supplier Bedu}}</ref><ref>{{Cite web|url=https://www.3pprinz.com/product-3p-hollow-turbik-series.php?lang=en|title=3P PRINZ - Hollow rotary disk pumps - Pompe 3P - Made in Italy|website=www.3pprinz.com|access-date=2019-12-20|archive-date=2020-08-06|archive-url=https://web.archive.org/web/20200806122911/https://www.3pprinz.com/product-3p-hollow-turbik-series.php?lang=en|url-status=dead}}</ref><ref>{{Cite web|url=https://magnatexpumps.com/mobile/hollow-disc-pump.php|title=Hollow Disc Pump|website=magnatexpumps.com|access-date=2019-12-20|archive-date=2020-08-06|archive-url=https://web.archive.org/web/20200806125134/https://magnatexpumps.com/mobile/hollow-disc-pump.php|url-status=dead}}</ref><ref>{{Cite web|url=https://candyne.com/hollow-rotary-disc-pump/|title=Hollow Rotary Disc Pumps|date=November 4, 2014}}</ref>
* [[Peristaltic pump]]s have rollers which pinch a section of flexible tubing, forcing the liquid ahead as the rollers advance.  Because they are very easy to keep clean, these are popular for dispensing food, medicine, and [[Concrete pump|concrete]].