Internal Gear Pumps: Smooth, Quiet and Precise

Internal gear pumps are a popular choice for hydraulic systems requiring quiet operation, high efficiency, and precise flow control. Known for their compact design and excellent suction capabilities, these pumps are ideal for handling a wide range of fluids – including those with higher viscosities.

How Do Internal Gear Pumps Work?

Invented by Jens Nielsen in the early 20th century, internal gear pumps use a clever offset gear arrangement to deliver smooth, continuous flow. Here’s how they operate:

• A rotor (external gear) meshes with an idler (internal gear) inside a crescent-shaped cavity.
• As the gears rotate, fluid is drawn into the expanding cavities on the inlet side.
• The fluid travels around the pump casing and is compressed as the gears re-mesh on the outlet side.
• The crescent-shaped partition separates the inlet and outlet, preventing backflow and ensuring consistent pressure.

This design allows internal gear pumps to deliver low-pulsation flow, making them ideal for applications where noise, vibration, and precision matter.

Can Internal Gear Pumps Be Reversed?

Most are not reversible due to their asymmetric design and the fixed position of the crescent partition. However, some specialised models offer bidirectional flow capabilities – typically with modified internal geometries.

If you need a reversible pump, our team can help identify the right solution based on your system’s requirements.

Are They Quiet?

Yes – internal gear pumps are among the quietest hydraulic pump types available. Their smooth gear engagement and low-pressure ripple make them ideal for noise-sensitive environments. Key design features include:

• Internal gear geometry for smoother fluid movement
• Tight tolerances that reduce vibration
• Low operating speeds that minimise mechanical noise

These attributes make these pumps a top choice for precision machinery, laboratory equipment, and mobile hydraulic systems.

Want to Learn More About Hydraulic Pumps?

If you’re comparing hydraulic pump types or designing a new system, check out our Hydraulic Pumps Ultimate Guide – covering:

• Internal versus external gear pumps
• Vane, piston, and screw pump comparisons
• Ideal applications for each pump type
• Tips for selecting the right pump for your system

Whether you’re an engineer, technician, or procurement specialist, this guide is packed with insights to help you make informed decisions.

Global Supply and Trusted Expertise

We supply pumps from leading manufacturers including Bosch Rexroth, Voith, Bucher, Hydac and more. Whether you’re sourcing OEM replacements or custom-built solutions, we offer:

• Fast, reliable worldwide export
• Award-winning customer service
• Decades of hydraulic expertise
• Technical support to help you choose the right pump

Need Something Else?

Looking for other hydraulic equipment and components? We supply, design, repair, and ship thousands of hydraulic products – including:

Hydraulic Pumps | Hydraulic Valves | Hydraulic Cylinders | Hydraulic Filters | Custom Hydraulic Power Packs | Standard Hydraulic Power Packs | Hydraulic Repair Service   …and much more.

Our website showcases just a selection of what we supply. For impartial advice and access to thousands more hydraulic components, contact our expert team – wherever you are.