FAQ-External Gear Pumps

As the gears unmesh on the inlet side, they create an expanding volume that creates a vacuum, drawing fluid into the pump casing. The fluid is trapped between the gear teeth and the housing wall as the gears rotate around the outer perimeter. Finally, as the teeth remesh on the outlet side, the volume shrinks and forces the fluid out under pressure.

Yes. Because they are positive displacement pumps, they can evacuate air from the suction line to create a vacuum and draw fluid up into the casing. However, running them completely dry for extended periods can cause severe wear due to lack of internal lubrication.

EXCEL External gear pump is available up to 2000 lpm and pressure up to 10 Bar Design: S6"crewed or Flanged, Port Sizes: 0.5"x0.5" to 6"x6", ​Gear Box Drive, ​Engine Drive or PTO Drive

Because an external gear pump is a positive displacement pump, it delivers a fixed volume per revolution regardless of discharge pressure. If a downstream valve is closed, pressure will rapidly build up until the motor stalls, the pump housing ruptures, or piping fails. A pressure relief valve (PRV) on the discharge line or integrated into the pump cover prevents over-pressurization.

External gear pumps perform exceptionally well with clean, viscous liquids and high-pressure hydraulic applications:

• Ideal fluids: Hydraulic oils, lubricating oils, fuels, polymers, resins, additives, and chemical feedstocks.
• Avoid: Abrasive slurries or fluids containing solid particles, as suspended solids quickly wear down gear teeth and tight tolerances.