Please fill out the form below to request a quote or to request more information about us. please be as detailed as possible in your message, and we will get back to you as soon as possible with a response. we're ready to start working on your new project, contact us now to get started.
Mastering Internal Eccentric Gear Pump Working Principle and Maintenance
2026-06-09
Trustech
18
An internal eccentric gear pump is a type of positive displacement pump that is widely used across various industrial applications, from automotive and chemical processing to food and beverage production. Its unique design offers advantages such as high efficiency, robust construction, and low noise operation, making it an indispensable tool in modern industrial processes.
This article aims to provide a comprehensive guide on the working principle of internal eccentric gear pumps and essential maintenance practices. By understanding how these pumps operate and maintaining them correctly, you can ensure optimal performance and extend their lifespan.
What is an Internal Eccentric Gear Pump?
An internal eccentric gear pump is designed to move liquids using rotating gears. The pump consists of two gears: a rotor (inner gear) and an idler (outer gear).
The rotor is mounted on a shaft and is driven by an electric motor. The idler gear is mounted within the rotor and is driven by the rotor gear. This design allows the pump to handle high viscosity fluids with ease and ensures smooth flow.
Key Components of Internal Eccentric Gear Pumps
- Rotor (Inner Gear)
- The rotor is the smaller gear with external teeth.
It rotates within the larger idler gear, creating a pumping action.
Idler (Outer Gear)
- The idler is the larger gear with internal teeth.
It rotates within the rotor, driving fluid through the pump.
Crescent Seal
- A fixed, crescent-shaped seal is installed between the rotor and idler.
- It separates the suction and discharge zones, preventing fluid from flowing back.
Working Principle of Internal Eccentric Gear Pumps
Understanding the working principle of an internal eccentric gear pump is crucial for troubleshooting and maintenance. The pump operates by creating and collapsing fluid cavities, which transport the fluid through the pump.
Step-by-Step Operation
- Cavity Formation (Suction Side)
- As the rotor rotates, the teeth of both gears disengage on the side opposite where they mesh.
This creates an expanding cavity, which draws in fluid from the suction port due to atmospheric pressure.
Fluid Transport
- The fluid is carried around the pump between the gears.
The crescent seal prevents backflow from the discharge to suction side.
Cavity Collapse (Discharge Side)
- As the gears approach the meshing point, the cavities shrink.
The meshing of the gears forces the fluid through the discharge port.
Continuous Rotation
- The continuous rotation ensures a steady flow of fluid.
- The overlapping phases result in smooth, pulse-free flow.
Maintenance Practices for Internal Eccentric Gear Pumps
Proper maintenance is essential to ensure the longevity and efficiency of internal eccentric gear pumps. Here are some best practices:
Regular Inspection Schedule
- Inspection Frequency: Monthly or bi-monthly checks are recommended.
- Components: Check the rotor, idler, seals, and bearings.
Lubrication and Seal Checks
- Lubrication: Regularly check and replace lubricant as needed.
- Seal Condition: Inspect seals for wear and tear. Replace as required.
Cleaning and Sealing Recommendations
- Cleaning: Clean the pump regularly to remove debris and ensure proper operation.
- Re-sealing: Apply proper sealing compounds to maintain tightness.
Common Problems and Troubleshooting
Fixing a Leaking Internal Eccentric Gear Pump
- Inspection: Identify the source of the leak.
Check for worn seals, loose connections, or damaged components.
Seal Replacement:
- Replace worn or damaged seals with new ones.
Ensure proper sealing compound is applied during installation.
Alignment Check:
- Ensure proper alignment of the rotor and idler.
Misalignment can cause increased wear and higher leakage rates.
Pressure Relief Valves:
- Check the pressure relief valves to ensure they are functioning correctly.
- Properly functioning relief valves can prevent excessive pressure build-up and reduce the risk of leakage.
Other Maintenance Tips
- Filters: Use appropriate filters to remove impurities and particulates from the fluid.
- Routine Checks: Perform routine checks on the pump's health and performance.
- Temperature Monitoring: Monitor temperature during operation to prevent overheating.
Table Comparison: Internal vs. External Gear Pumps
| Feature | Internal Gear Pump | External Gear Pump |
|---|---|---|
| Efficiency | High | High |
| Noise Level | Low | Medium to High |
| Flow Smoothing | Smooth, Minimal Pulsation | Some Pulsation |
| Viscosity Handling | Excellent for High Viscosity | Limited High Viscosity Handling |
| Heat Generation | Lower Due to Relaxed Clearances | Higher Due to Tight Clearances |
| Shear Sensitivity | Lower Shear | Higher Shear |
| Applications | Chemicals, High Viscosity Fluids | Lower Viscosity Fluids, Solvents |
Conclusion
Final Thoughts
Regular maintenance and proper operation are key to maximizing the efficiency and longevity of internal eccentric gear pumps. Trustech Technology, as a leading manufacturer, emphasizes the importance of regular inspection, lubrication, and sealing checks to maintain the integrity of these critical components. Implementing these best practices will help you avoid common issues like leaking and ensure your pumps continue to function reliably over time.
Table of Contents
GET IN TOUCH WITH Us
recommended articles
From April 24 to 26, 2026, the 9th Symposium on Medical Membrane Technology and Applications, hosted by the China Membrane Industry Association and jointly organized by the College of Chemistry and Pharmacy of Guangxi Normal University, the Editorial Office of Membrane Science and Technology, and the Special Committee on Membrane Technology for Pharmaceutical and Biological Applications of the China Membrane Industry Association, with support from the National Innovation Center of Advanced Membrane Materials and the National Key Laboratory of Advanced Separation Membrane Materials, was successfully held in Guilin, Guangxi. Nearly 200 experts, scholars, corporate leaders, and engineering and technical personnel from universities, research institutes, hospitals, and enterprises across the country gathered to discuss the frontiers of medical membrane technology and trends in industrialization.
In NIPS and TIPS ultrafiltration hollow fiber manufacturing, the spinneret is not just a “die with holes.” A membrane spinneret must co-extrude polymer dope and bore fluid with strict concentricity, maintain a stable flow field through multi-hole distribution, and preserve a controlled thermal–mass transfer history to form a uniform lumen and selective skin. Regular textile spinnerets, by contrast, are optimized to produce solid filaments with comparatively broader tolerances and simpler flow control. Understanding these differences prevents misapplication and protects yield, uniformity, and membrane performance.
Ultrafiltration hollow fiber membranes owe much of their performance to how they are formed at the spinneret. In NIPS (non-solvent induced phase separation) and TIPS (thermally induced phase separation) lines, the spinneret is the control point that converts rheology, flow balance, and interfacial kinetics into pore architecture and mechanical integrity. Choosing a production route is not about perfection; it is about matching polymer system, pore targets, and throughput to a spinneret and line design that deliver stable, reproducible fibers.
TRUSTECH is accelerating the industrialization of high performance hollow fibers used across water treatment, healthcare, and chemical applications.
China TRUSTECH has been granted an invention patent for a "Modular Multi Orifice Hollow Fiber Membrane Spinneret Head, " marking a new milestone in scalable, serviceable, and specification compatible spinneret architecture for hollow fiber membrane production. As a China leading membrane spinning machine and hollow fiber membrane spinneret manufacture, TRUSTECH is advancing the industry with modular engineering that enables linear orifice expansion, separated maintenance, and cross spec compatibility—all without replacing the entire spinneret assembly.
The dialysis membrane machine market is poised for growth, driven by rising global demand and an aging population. Key for 2026 are innovations that enhance biocompatibility, permeability, and production efficiency. Leading manufacturers must balance speed with quality to meet future treatment needs while enabling scalable, upgradeable production lines.
In the field of hollow fiber membrane spinneret heads, Trustech has received another piece of good news: its independently developed "Modular Multi Orifice Hollow Fiber Membrane Spinneret Head" has been granted a national invention patent (Authorization Announcement No. CN104894663B). With its digitized, modular, and flexible design innovations, this patented technology injects strong momentum into the industry's development.
The hollow fiber membrane industry for water purification and wastewater treatment relies on stable, efficient NIPS wet spinning. Trustech’s FCT 6th Generation Spinneret is the core forming component designed specifically for wet-process NIPS. Building on Gen5 strengths—independent spinneret core, pinless structure, and high-precision forming—Gen6 adds structural innovations for multi-hole expansion and per-hole independent control, supporting 8, 12, 16-hole configurations. During spinning, each hole’s dope (membrane-forming feed) and bore fluid (lumen-forming) can be switched on/off and regulated independently, eliminating the traditional pain point of “entire line stoppage due to a single-hole failure.” This is particularly valuable under unstable materials or large process fluctuations, boosting productivity, reducing waste and labor costs, and enabling large-scale manufacturing..
Riding the wave of innovation driven industrial upgrading, TRUSTECH Technology has achieved another breakthrough in hollow fiber membrane spinneret technology. Its independently developed "Embedded Multiple Holes Hollow Fiber Membrane Spinneret" has been granted a national invention patent (Patent No. : CN20151078942.X). This patent, the result of years of technical accumulation, injects fresh momentum into the industry while reinforcing the company's leadership in the field.
Non-solvent induced phase separation (NIPS) makes it possible to spin hollow fiber membranes with a thin selective skin and a supportive porous substructure—at industrial scale. This article explains the core modules of a modern NIPS hollow fiber spinning line, shows how configurations differ for environmental filtration, medical dialysis, and gas separation, and closes with a practical FAQ.
Ready to work with us ？
About Trustech
Quick Links
Categories
Contact Us
Follow Us