How to Prevent and Resolve Rock Jams in Jaw Crushers?

Time: 10 June 2021

Preventing and resolving rock jams in jaw crushers is crucial for maintaining efficiency, safety, and prolonging the life of the equipment. Below are some effective strategies for both preventing and resolving rock jams:

Preventing Rock Jams in Jaw Crushers

Preventive measures are essential to avoid operational downtime and damage to the machine:

1. Proper Feed Size:

   • Ensure that the material being fed into the jaw crusher is within the specified size limits.
   • Oversized rocks can wedge themselves in the crushing chamber and cause jams.

2. Consistent Feeding:

   • Implement a steady and uniform feeding process to avoid surges or overloading.
   • Use a feeder system that regulates the flow of material into the crusher, such as vibratory or grizzly feeders.

3. Pre-screening:

   • Install a pre-screen or scalping screen to remove fines and smaller materials before they enter the crusher.
   • This minimizes the likelihood of blockages and ensures better crushing efficiency.

4. Material Inspection:

   • Inspect the material for tramp metal or other uncrushable objects before feeding it into the jaw crusher.
   • These objects can damage the crusher or cause jams.

5. Adjust Crusher Settings:

   • Regularly adjust the crusher’s closed-side setting (CSS) to suit the material properties and required output size.
   • Maintaining the correct CSS helps reduce the risk of bridging or jamming.

6. Operate Within Design Limits:

   • Run the crusher within its specified operational limits to prevent overloading.
   • Consult the equipment manual for recommended throughput and material characteristics.

7. Routine Maintenance:

   • Inspect wear parts like jaw plates, cheek plates, and toggle plates.
   • Replace worn-out parts that could impair the crusher’s functionality and lead to jams.

Resolving Rock Jams in Jaw Crushers

If a jam occurs, safety precautions must be followed before resolving the issue:

1. Ensure Safety First:

   • Turn off the crusher and disconnect the power supply to avoid accidental operation.
   • Follow lockout/tagout procedures to ensure safety during jam resolution.

2. Manual Clearing:

   • Use tools like crowbars, hydraulic rams, or jacking systems to safely dislodge the jammed material.
   • Avoid using bare hands or standing directly above the crusher chamber.

3. Reverse Operation:

   • Certain jaw crushers have reversible operation functions.
   • Reverse the crusher’s rotation to dislodge stuck material.

4. Hydraulic Assistance (if equipped):

   • Some crushers feature hydraulic clearing mechanisms to push out jammed rocks safely.
   • Follow the manufacturer’s guidelines for hydraulic clearing.

5. Check Cause of the Jam:

   • Inspect the crusher for improper feed size, tramp material, or worn parts that may have contributed to the jam.
   • Address any underlying issues to prevent future jams.

6. Inspect and Repair:

   • After clearing the jam, inspect the crusher for any potential damage or wear caused during the jam.
   • Replace worn parts like jaw plates or toggle plates as needed.

7. Train Operators:

   • Ensure operators are trained in correctly feeding material into the crusher and identifying signs of potential jams.
   • They should know the emergency protocol in case of a jam.

Additional Tips

• Use software or monitoring systems to track crusher performance and detect abnormalities early.
• Regularly clean the feed area and hopper to prevent the buildup of debris.
• If jams persist, reassess the feed material properties like moisture levels, hardness, and crusher compatibility.

By combining prevention techniques with proper jam-resolution practices, you can improve jaw crusher performance, reduce wear and tear, and minimize downtime.

Contact Us

Shanghai Zenith Mineral Co., Ltd. is a leading manufacturer of crushing and grinding equipment in China. With more than 30 years of experience in the mining machinery industry, Zenith has built a strong reputation for delivering high-quality crushers, mills, sand-making machines, and mineral processing equipment to customers around the world.

Headquartered in Shanghai, China, Zenith integrates research, production, sales, and service, providing complete solutions for aggregates, mining, and mineral grinding industries. Its equipment is widely used in metallurgy, construction, chemical engineering, and environmental protection.

Committed to innovation and customer satisfaction, Shanghai Zenith continues to advance in intelligent manufacturing and green production, offering reliable equipment and comprehensive after-sales service to help clients achieve efficient and sustainable operations.

website: https://www.chinagrindingmill.net

Email:info@chinagrindingmill.net

Whatsapp:+8613661969651

• Previous: How Are Diamond Crushers Utilized in South Africa's Mining Industry?
• Next: What Should a Metallurgical Test Plan Include for Crusher Selection?