Bronte Precision

Large & Complex Machining

Bronte Precision are a Made in Yorkshire Bronze Member

Gear Pumps: Internal vs External

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How they Work

Internal Gear Pumps have an outer rotor gear which turns, driving the idler (inner) gear. As these two elements come into contact with each other, liquid is drawn into the pump which travels along the casing and to the discharge end of the pump, forced out as the gear teeth mesh together.

External Gear Pumps work similarly with two gears coming into contact to generate flow, only instead of these gears turning in the same direction, they will typically rotate against each other. As the gears mesh they will draw in the liquid, and the teeth hold the liquid as they rotate against the casing before meshing together again and forcing the fluid out of the discharge port. External Gear Pumps are usually found in single or double configurations and can use a variety of different gear designs including Helical, Spur or Herringbone.


Internal Gear Pumps are very versatile and can pump a wide variety of fluids and are particularly popular in applications involving chemicals, bitumen and resins. They are capable of pumping very viscous fluids, but will struggle with large solids. Internal Gear Pumps have very small tolerances and as such these large tolerances can easily block and damage the pump.

External Gear pumps are often used in sampling and metering applications. They are suitable for high pressure applications and can operate at low to medium temperatures. Often used to move polymers, chemical additives and fuels. External Gear Pumps should not be used in applications involving solids, abrasive materials or at high temperatures.

Gear Pumps are used across a variety of applications, and one of the most simple in terms of maintenance. Bronte Precision have been providing sub-contract machining of various gear pump components including the machining of casings, shafts and gear cutting for flat helical and spur gears. Contact us today with your requirements.