Gear pumps are available in a range of designs, and each of these have various applications they are well suited to. As a type of Rotary Positive Displacement Pump, gear pumps use two rotating gears with teeth which intermesh. These gears work together to move fluids by creating a vacuum to draw it into the pump and then transfer it to the discharge. Gear pumps generally come in two types: internal and external. Each of these have different uses and benefits, so if you are wondering what gear pumps are used for, it ultimately depends on the type.

External Gear Pump Applications

An external gear pump is made up of two identical gears mounted on shafts and interlock together. One of these gears will be driven by a motor, and this then drives the second gear. In some gear pumps, both of the gears are motor-driven. Most of these pumps use spur gears, but other designs such as helical form or herringbone are also possible. Spur teeth are the easiest to manufacture but also slightly less efficient than other options. Because of external gear pumps’ design, they are not as efficient for moving thin fluids as they rely on fine clearances. Spur gear pumps will handle thin fluids better than other options.

External gear pumps are often used when high pressure is required. Some typical uses for external gear pumps include;

  • Fuel oils and lube oils
  • Chemical additives
  • Chemical mixing or blending
  • Acids
  • Hydraulic applications (industrial, agricultural and mobile)
  • Solvents
  • Alcohols

Internal Gear Pump Applications

Internal gear pumps also come in various types, but the overall functionality is the same. They are essentially a gear inside a gear, and they only use spurs. With less supporting bearings than external gear pumps and larger teeth, these pumps are better suited to highly viscous liquids. Internal gear pumps are much more versatile and have a lot of uses, as well as being much simpler to maintain. Gerotor pumps are another type of gear pump which are also similar to internal gear pumps. You can find Gerotor pumps in automobile gearboxes and for use with aviation fuel because they are super compact and cheap to produce.

Internal gear pumps are often used for high viscosity liquids. Some typical uses for external gear pumps include;

  • Fuel oils and lube oils
  • Polymers and resins
  • Bitumen, asphalt and tar
  • Food products including peanut butter, cacao butter, sugar, chocolate, corn syrup, vegetable fats and oils.
  • Inks, paints and pigments

If you are unsure if gear pumps are the right choice for you or want to know more about the types of gear pumps we have available, get in touch with our expert team.

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