Predictable Uptime: The importance of routine inspections for impact crushers
3. A crane is required for impact crusher maintenance. A jib crane built into the structure, properly located to access the crusher and new parts loading area, is recommended. This dedicated crane is relatively inexpensive and can improve safety and speed maintenance.
Checklists can help operators maintain equipment properly. It is also important to follow company rules and the pertinent Mine Safety and Health Administration (MSHA) and Occupational Safety and Health Administration (OSHA) regulations. Safety should never be compromised. The following are fundamental checklists designed to identify areas and parts needing routine inspection. Slight modifications to the checklists may be warranted, depending on the manufacturer and type of impact crusher in operation.
- Visually check to make sure the crushing chamber is empty (free of debris, rags, wire, rebar, stone, or any material that could impair startup or operation).
- Check for clearance between the blow bar and side liners.
- Check apron settings (track and log wear, and plan for next casting change).
- Check blow bar and apron liner condition; look for cracks or uneven wear. (Large, easily accessible, built-in inspection doors should be a part of the crusher design.)
- Check for loose bolts, inside and out; tighten before startup.
- Make sure all the guards and covers are secure.
- If applicable, check hydraulic fluid levels and start the hydraulic system, checking for proper operation.
- Inspect under the crusher and remove any excess stone buildup or foreign materials.
- Start the under-crusher conveyor and ensure proper operation.
- Start the crusher and note any vibration; excess vibration may indicate loose or failed rotor parts or material buildup on sheaves.
- Check and log motor amp draw, noting any change in the trend (an increase in amp draw indicates increased friction — motor bearings, crusher bearings, rotor rubbing against liners, etc.).
- Introduce feed; material should be evenly distributed across the crusher for even wear.
- Listen and feel for unusual operation; a howl could indicate worn bearings; screeches, grating, and grinding could mean something is loose.
- Again, visually inspect for loose bolts.
- Grease bearings and lubrication points as recommended by the manufacturer.
- Clean up any spillage around and under the machine.
- Check to make sure the crushing chamber is empty — free of debris, rags, wire, rebar, stone, or any material that could impair startup for the next shift.
- Check for any damage that occurred during the shift.
- After shutdown, check and log the bearing temperature noting any change in the trend. Typical bearing temperature is between 140 to 150 degrees F. Using an infrared heat gun is an easy and quick way to monitor bearing temperatures throughout the plant.
- Check all fasteners and replace those that are loose or missing.
- Check any seal arrangement on the crusher.
- Check the crusher frame for any cracks and repair as soon as possible; cracks only get worse with time.
- If using a V-belt drive, check belt tension and condition.
- Check hydraulic components, pressures, and system functions.
- Check for wear in the feed chute.
- Make sure chains or rock curtains are in good shape.
- Check under the crusher for wear on the pan, belt, and discharge chute.
- Grease the motor once a year or as recommended by the manufacturer. Be careful not to over grease.
- If the machine has a hydraulic unit, empty out the hydraulic tank and clean it, clean or replace all strainers and filters, and refill the unit with new hydraulic oil.