Gear Pumps
8/18/2008
“A Gear pump uses the meshing of gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. Gear pumps however are also widely used in chemical installations to pump fluid with a certain viscosity. There are two main variations; external gear pumps which use two external spur gears, and internal gear pumps which use an external and an internal spur gear. Gear pumps are fixed displacement, meaning they pump a constant amount of fluid for each revolution. Some gear pumps are designed to function as either a motor or pump.”
Wikidpedia: http://en.wikipedia.org/wiki/Gear_pump [8/18/2008]
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Notes
As the gears rotate they separate on the intake side of the pump, creating a void and suction which is filled by fluid. The fluid is carried by the gears to the discharge side of the pump, where the meshing of the gears displace the fluid. The mechanical clearances are small—on the order of a thousandth of an inch (micrometres). The tight clearances, along with the speed of rotation, effectively prevent the fluid from leaking backwards. The rigid design of the gears and housing allow for very high pressures and the ability to pump highly viscous fluids. Many variations exist, including; helical and herringbone gear sets (instead of spur gears), lobe shaped rotors similar to Roots Blowers (commonly used as superchargers), and mechanical designs that allow the stacking of pumps.
Wikidpedia: http://en.wikipedia.org/wiki/Gear_pump [8/18/2008]
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Review Articles
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US Patents
8/5/2008
7,407,373
Internal gear pump and an inner rotor of such a pump
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Journal Articles
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Books
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