Cylindriskt kugghjul | Viking Pump

Glossary Right Side Image

Image showing the driver and driven gears in an external gear (spur gear) pump.

Abbreviation / Acronym

SG

Classification

What is a spur gear pump?

Spur gear pumps are a series of Viking Pump external gear pumps named such due to the cut of the external gears. This series is referred to as the SG Series™.

Spur gear, or external gear, pumps are a type of rotary positive displacement gear pump that features two identical external gears where one gear is the drive gear and one is the driven. The liquid is transferred from between the gear teeth by the rotation of the pump. Click here to view a video on this subject.

How do external gear pumps work?

External gear pumps are similar in pumping action to internal gear pumps in that two gears come into and out of mesh to produce flow. However, external gear pumps use two identical gears rotating against each other. One gear is driven by the motor (driver gear) while the other (driven) gear meshes with and is rotated by the driver gear.

Image showing the driver and driven gears in an external gear pump.

As the gears come out of mesh, they create an expanding volume on the inlet side of the pump. This creates a vacuum which pulls liquid into the pump. Liquid is trapped between the gear tooth cavities and the close fitting casing wall. The rotation of the gears carries the liquid around to the outlet side of the pump. The liquid does not pass between the gears. At the outlet, the meshing of the gears forces the liquid through the outlet port.

Image of the liquid flow path in an external gear pump.

What are external gear pumps used for?

Since external gear pump gears are supported on both sides, these gear pumps are routinely used for high-pressure applications including hydraulics and pipeline injection. They can come in many sizes to accommodate a wide variety of high speed, high pressure applications.

Image of hydraulics, a typical application for external gear pumps.