Forget what you know about gear pumps

Forget what you know about gear pumps

Most of us are well acquainted with gears, especially when it comes to gear pumps. Gear pumps typically use gears with teeth similar in geometry to those used for power transmission: they are symmetrical. Symmetrical teeth are needed because gear sets used in mechanical power transmission often rotate clockwise and counterclockwise.

Gear sets used in hydraulic motors also must allow bidirectional rotation. In fact, that’s one of the great advantages of hydraulics: simply shifting a valve reverses rotational direction of a hydraulic motor. It doesn’t get much simpler than that.

Gear pumps, on the other hand, pose a different scenario. Most gear pumps (or any hydraulic pump, for that matter) rarely, rotate in two directions. Whether they’re driven by an electric motor, internal-combustion engine, or other prime mover, chances are, the direction of rotation will be in only in one direction.

However, most gear pumps have symmetrical teeth — the tooth profile of the leading face is identical to that of the trailing face. This may be one reason why gear pumps tend to be noisy and generate pressure pulsations. So if you were to remove the constraint of designing gear teeth for pumps to be symmetrical, maybe you could reduce noise and pressure pulsations. You might even make the pump operate more efficiently.

I’d love to take credit for this type of forward thinking, but I heard of the idea from Ram Sudarsan Devendran, a Ph.D. student at the Maha Fluid Power Research Center, Purdue University. Ram will present a paper at next year’s IFPE Technical Conference summarizing this concept in a paper titled, “Experimental Characterization of External Gear Machines with Asymmetric Teeth Profile.”

But this is just one of nearly 100 interesting and informative technical papers that will be presented next March 5 to 7 in Las Vegas at the IFPE Technical Conference. I’ve been fortunate to be a part of the IFPE Technical Conference review board, so I’ve had a sneak peek at the topics and abstracts of papers to be presented.

Many other topics look interesting, too, but space will not allow me to delve into them here. I’m told the IFPE Conference lineup will be ready soon, so go to to learn the latest.

Update: The IFPE Conference schedule has been released. Click here to view it.

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