Internal Gear Pump
NBL Series Pumps – The Synonym of Ultra-Low Noise for Comfortable Operation
✅ Ultra-low noise performance
✅ Low flow pulsation
✅ Excellent durability
✅ Widely used in machine tools, injection molding machines, electric forklifts, bending machines, etc.
ISO 9001 Quality System
Standardized control from production to inspection.
ISO 9001 Quality System
Documents available for applicable products and components.
Multiple invention patents
30 Self-developed Patents, Independent Core Technology
Mian Pums Series
Product Features
Low Noise & Low Pulsation
Long Service Life
Excellent High Pressure Endurance
Product Features
For Hydraulic Servo Systems
High Efficiency & Energy Saving
For injection molding, die casting and hydraulic machines, it cuts energy use by 20%-80%, shrinks oil tank size, and runs cleaner & greener.
Rich Configuration

Superior Performance
Lower Costs
Wide Compatibility
Energy-efficient Performance
Boasting high pressure resistance, long service life and low noise, it replaces piston pumps, vane pumps and external gear pumps. It fits all industrial hydraulic systems, including forging, power generation, military vessels, petrochemical industries and more.
Cartridge relief valve installed per customer requirements
We develop internal gear pumps of various displacements per customers’ requirements & supplied samples. They apply to low-pressure lubrication systems, special fluids, extreme working conditions and high-pressure systems, with a maximum pressure of 32 MPa.

Product Applications
Faults & Troubleshooting
| Fault Phenomenon | Cause of Fault | Troubleshooting Method |
|---|---|---|
| Insufficient flow or no oil output | High suction resistance of oil suction port filter | Reduce suction resistance |
| Air leakage in oil suction pipe, oil level is too low | Eliminate air leakage causes, raise oil level | |
| Suction filter screen is blocked | Clean the filter screen | |
| Oil temperature is too high | Cool the oil | |
| Parts wear | Replace parts | |
| Pump reverse rotation | Correct the rotation direction | |
| Key sheared off | Replace with new key | |
| Pressure fluctuation or no pressure | Pressure valve in hydraulic system cannot work normally | Replace the pressure valve |
| Insufficient suction, entrained air | Eliminate suction resistance, increase suction pipe diameter | |
| Loose bolts on oil suction pipe, air leakage | Tighten the suction port connecting bolts | |
| Parts in pump are damaged | Replace damaged parts | |
| Excessive noise | Excessive suction resistance, insufficient suction | Increase pipe diameter, reduce elbows |
| Air in the pump body | Fill the pump body with working oil before starting | |
| Seal ring of front cover or oil distribution plate is damaged | Replace the seal ring | |
| Pump mounting frame is loose | Tighten the frame | |
| Excessive misalignment of coaxiality and perpendicularity during pump installation subjects the main shaft to radial force. | Reinstall and correct coaxiality and perpendicularity | |
| Severe bearing wear | Replace the bearing | |
| Excessive oil viscosity | Reduce oil viscosity | |
| A large amount of foam in the tank oil | Eliminate air intake causes | |
| Rapid temperature rise of oil | Too small tank volume or poor cooling effect | Increase tank volume, improve cooling device |
| Pump parts are damaged | Replace damaged parts | |
| Excessive oil viscosity | Select suitable oil | |
| Oil pump leakage | Front cover oil seal is damaged | Replace damaged parts |
| Oil return hole and external oil drain port in pump body are blocked | Clean the oil return hole and external oil drain port of the pump body |