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Internal Gear Pumps

Internal Gear Pumps

Internal gear pumps operate using two interlocking gears, one nested inside the other. They rotate in opposing directions, creating a suction force that draws fluid into the pump, and when the gear teeth mesh, it pushes the fluid out. 

Operating Principle of Internal Gear Pumps 

Internal gear pumps operate based on the interaction between two interlocking gears—an outer gear and an inner gear—within a housing. The key operating principles of internal gear pumps involve: 

Gear Interaction  

Internal gear pumps consist of an outer gear with external teeth and an inner gear with internal teeth. These gears rotate together, with the inner gear being smaller and positioned inside the outer gear. As they rotate, the gear teeth mesh, creating cavities that trap and move fluid from the suction port to the discharge port. 

Fluid Movement 

As the gears rotate, fluid is drawn into the pump through the suction port. The expanding cavities between the gear teeth create a low-pressure zone that draws in the fluid. As the gears continue to rotate, the meshing of gear teeth reduces the cavity size, compressing and displacing the fluid towards the discharge port. 

Fluid Sealing  

The gears maintain close tolerances with the pump housing, ensuring minimal leakage between the suction and discharge sides. This design results in positive displacement, which means a consistent volume of fluid is displaced with each revolution of the gears. 

Flow Control 

The flow rate is proportional to the speed of rotation. Controlling the speed of the gears enables fine-tuning of the flow rate, allowing for precise control over the fluid delivery. 

Advantages of Internal Gear Pumps 

  • Viscosity Handling: Ideal for transferring high-viscosity fluids. 
  • Versatility: Handles various viscosities and small solid particles. 
  • Performance: Suitable for high-pressure and high-flow applications. 
  • Adaptability: Functions well in challenging conditions like high temperatures and low Net Positive Suction Head (NPSH). 
  • Self-Priming: Capable of frequent starts and stops. 
  • Applications: Widely used in industries like asphalt production, chemical manufacturing, oil and gas, and food and beverage. 

Applications of Internal Gear Pumps 

  • Asphalt & Bitumen Production: Effective in handling sticky substances in large-scale production. 
  • Chemical Industry: Used for precise metering and transferring of ingredients. 
  • Oil & Gas Sector: Reliable in high-pressure applications. 
  • Food & Beverage: Ensures accurate transfer and metering of ingredients. 

Important considerations when selecting Internal Gear Pumps 

  • Flow Rate: Selecting the right internal gear pump involves considering the desired flow rate. Insufficient flow rates may lead to poor performance, while excessive rates can cause pressure issues and inefficiencies. 
  • Viscosity: Internal gear pumps handle a wide viscosity range. Lower viscosity fluids move more easily, while higher viscosity fluids may require adjustments to gear speed for proper handling. 

Why buy internal gear pumps from AxFlow? 

AxFlow provides a diverse range of internal gear pumps tailored to various industries. Our experts offer comprehensive support, aiding in pump selection, specification, installation, and maintenance. Reach out to AxFlow for personalized guidance in choosing the ideal internal gear pump for your specific requirements. 

Eoin Cahill
Water & Wastewater, Power generation, Construction & Mining
Brian Coleman
Food & Beverage Sectors.
Brajan Saraci
Pharmaceutical, BioPharma, Chemical and Petrochemical Sectors
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