Background
In underground mining environments, maintaining oil cleanliness in final drives is critical to ensure reliability and extend component life. A Caterpillar R2900 loader operating in a hard rock mine presented elevated contamination levels in both front and rear differentials, with initial ISO cleanliness recorded at 24/23/21, well above the customer’s target of 18/16/13.
Application
The application involved mobile kidney loop filtration of the front and rear differentials, each with oil capacities of approximately 77L and 83L respectively, using high-viscosity SAE 60 oil in a challenging underground workshop environment.
Due to the oil viscosity and system configuration, conventional fixed displacement filter carts experienced pump cavitation, limiting their effectiveness.
HYDAC Solution
HYDAC supplied two OFT-3 mobile filter trolleys, each dedicated to one differential. The units featured variable frequency drive control, enabling flow adjustment to suit the application and avoid cavitation issues.
Key features included:
- Variable flow control to suit high-viscosity oil conditions
- Cascading filtration with 10 µm and 5 µm elements
- Custom hose connections for improved visibility of flow and air entrainment
- Verification using a calibrated fluid control unit
The system allowed stable operation, with flow rates adjusted between 8–15 L/min depending on differential configuration.
Results
Within approximately 2.5 hours of operation, both front and rear differentials achieved significant cleanliness improvements. ISO cleanliness levels were reduced from approximately 20/18/13 to a stabilised range of 15/13/8 to 15/14/9, exceeding the customer’s target.
The results demonstrated consistent performance across both circuits, despite differences in oil draw conditions and system geometry.
Conclusion
The OFT-3 filter trolley proved highly effective in addressing contamination challenges in high-viscosity differential oils within a demanding mining environment.
The ability to control flow and prevent cavitation was critical to the success of the application. The solution not only achieved the required cleanliness targets but also demonstrated strong potential for broader deployment across the customer’s mobile equipment fleet.
