How to Properly Operate and Maintain a Mining Contra-Rotating Axial Flow Local Fan?

Mining contra-rotating axial flow local fans are crucial in ensuring proper ventilation in underground mining operations. Their effective functioning helps maintain air quality, ensuring the safety and productivity of the workers. However, to achieve optimal performance and prevent malfunctions, it is essential to follow proper operation and maintenance procedures. Below are some important guidelines to keep in mind.

1. Single-Stage vs. Multi-Stage Operation

For short-distance ventilation, a single-stage fan is sufficient. However, for long-distance ventilation, it is necessary to operate two or more stages of contra-rotating fans. This ensures that the airflow is strong enough to cover the longer distances required in deep or extensive mining tunnels.

2. Pre-Operation Checks

Before operating the fan, it is essential to ensure that there are no foreign objects or debris inside the fan. All fasteners should be checked to make sure they are complete and securely connected. Additionally, confirm that the impeller rotates in the correct direction. Test the rotation to ensure it is smooth and free of abnormal noises. Regular inspections should be carried out during operation, and records must be kept for reference.

3. Avoiding Foreign Object Ingestion

It is strictly forbidden to hang or place any objects near the air inlet side of the fan, as this could lead to the objects being sucked into the fan, causing damage or accidents. If the protection grate on the collector is damaged, the fan should not be operated until repairs are made.

4. Operational Monitoring

During operation, regularly inspect whether the fan is producing normal operational sounds. Check for any loose parts or abnormalities that could indicate a potential problem. Immediate attention should be given to any unusual signs.

5. Cleaning the Silencer Hole

Over time, dust can block the silencer hole, reducing the fan’s silencing effect. To maintain the fan’s optimal noise-reducing capabilities, clean the silencer hole using high-pressure airflow. Regular cleaning ensures the fan operates at peak efficiency.

6. Bearing Maintenance

The bearing operating temperature should not exceed 95°C (measured using a thermometer). Regular checks are required, at least once every 2,500 hours of operation or every six months. If the bearing grease is degraded, it should be replaced promptly. Before applying new grease, clean the bearings with gasoline. It is recommended to use Molykote grease and to fill the bearing housing with grease up to half to three-quarters of its clearance volume. If any bearing damage is found, replace it without delay.

7. Protecting the Flameproof Surface

When disassembling the motor, it is crucial to protect the flameproof surface. Apply 204-1 anti-rust oil to the flameproof areas to prevent corrosion or damage during maintenance.

8. Regular Maintenance Schedule

Perform minor repairs every six months and major repairs annually. This regular maintenance helps identify and fix issues before they affect the fan’s performance, thus preventing costly breakdowns.

9. Professional Management

The operation and maintenance of the fan should be handled by trained and professional personnel. Only qualified staff should manage the fan, ensuring that all tasks are carried out with the necessary expertise and safety measures.

Proper operation and maintenance of mining contra-rotating axial flow local fans are essential for ensuring the safety and efficiency of mining operations. Regular inspections, cleaning, and timely repairs will not only extend the fan’s lifespan but also help maintain optimal ventilation conditions in the mine. By adhering to these guidelines, mining operations can prevent costly repairs, enhance worker safety, and improve overall operational efficiency.