Crushers are used in the mining industry, construction, and other sectors to break large rocks down into smaller, more manageable pieces. There is a wide range of crushers available that employ different physical methods to achieve this goal. Below, we’ll look at the various types of crushers offered and explore the best methods for keeping your crusher machinery in top condition.
Types of Crushers
Jaw Crushers
A jaw crusher applies pressure to material with a movable lever against an immovable wall. The force exerted in the crushing chamber is generated and maintained by a flywheel moving the swing jaw, while the stationary jaw provides the resistance. Between the two surfaces, heavy materials such as stone and ore are broken into smaller pieces.
Gyratory Crushers
Often used as a secondary crusher to a jaw crusher — especially in mining, quarrying, or other applications where stone and rock need to be reduced to finer grades — gyratory crushers employ a circular movement to crush materials. Gyratory crushers use manganese steel surfaces, which are harder than stone, making them suitable for breaking down hard materials. The pieces continue to be crushed via the rotational movement of these opposing surfaces (usually one semi-static, and the other in full rotation) until the pieces are small enough to fall through the crushing chamber and into a collection bin.
Cone Crushers
Cone crushers use a rotating spindle with a hard encasement mantel to break down materials between the hardened surface and concave bowl. As materials fall through this compression area into a secondary area, the material is crushed again. This process continues until the material being crushed reaches the designated size and falls into the collection pile.
Grinding Mill
Commonly associated with the agricultural industry, grinding mills are a type of crusher that creates a compression chamber which crushes, grinds, and cuts material. Grinding mills are typically used for softer materials. Stone wheels grind grain or other items into a fine powder through weight and the abrasiveness of the grinding surface. Different texturing and channeling can allow for different levels of grit to be created, as well as increasing or decreasing resistance. Through constant rotation of the aggregate and the friction it creates, materials may be broken down to a very fine level.
Common types of grinding mills include:
- Pebble mill — Uses a substance to aid in attrition. Similar to a rock polisher.
- Autogenous/semi-autogenous mills — A rotating drum which breaks materials down with a cascade motion of material onto itself.
- Roller mill — Two opposing rollers in near contact with each other serve as the compression chamber.
- Buhrstone mill — Similar to the flour mills of antiquity.
- Tower mill — Vertical mill which utilizes a screw drive to move materials, but unlike an autogenous mill, there is no cascade motion involved.
Best Practices for Crusher Maintenance
Regular maintenance is critical when it comes to the safe and effective operation of any milling or crushing machine. These machines endure enormous amounts of stress for extremely long periods of time, relentlessly crushing incredibly hard materials down to usable levels. As material is reduced, it also creates significant dust and debris, which can also affect performance and create premature wear.
Here are four ways you can maintain all types of crushers.
- Preventative maintenance utilizes scheduled checks and inspections. Replacing parts before they break down will save you headaches in the future.
- Predictive maintenance relies on knowing how long certain pieces last before they need to be replaced. Lubricants, belts, filters, and operating hours on motors help determine these replacements.
- Reactive maintenance fixes components as they break to avoid further damage, but tends to result in more significant downtime.
- A scheduled maintenance plan can keep major damage costs down and ensure your machines keep running efficiently through regular inspection. Keep a log of maintenance checks to ensure they are completed on time.
Maintenance Tips for Crushers
Jaw Crushers
- Check oil regularly, making sure it is free of dirt and contaminants.
- Check jaw dies every day, and make sure bolts are fastened securely.
- Maintain crusher backing to ensure proper vibration and impact protection.
- Keep breathers clean.
- Make sure the toggle area is clean, especially prior to any adjustments.
- Wash out seats and plates daily.
Gyratory Crushers
- Check spider bushing clearance monthly, every 500 hours, or with every mantle change. Whichever comes first.
- Monitor and maintain bushing lubrication levels every day (about 1.4" above bushing flange). Make sure "extreme pressure" additive is added.
- Check balance cylinder(s) every 30 days of operation.
- Keep oil and lubrication clean. Check daily, every 8 hours.
- Follow crusher backing maintenance schedule carefully to avoid undue damage to equipment.
- Every 40 hours, check for leaks and inspect Y strainers.
- Every month, inspect safety devices and perform an oil analysis.
- At least once per year (or every 2,000 hours) change all oil.
- Know and use the proper mantle for your crusher. Failing to do so can result in serious damage.
Cone Crushers
- Keep cone crushers choke fed during operation. This will prolong manganese service life and maintain quality shape of the product.
- Maintain oil cleanliness. Check daily.
- Lubricate bearings every 500 hours and change oil every 6,000 hours.
- Make sure crusher backing is applied regularly to protect parts, components, and to fill in gaps.
- Use the correct oil for manufacturer’s requirements and climate conditions.
- Check the main frame for damage. Use a micrometer for variance and quality control. Replace or machine areas that cannot be filed down with an emery cloth.
- Check alarms daily to make sure they are working properly.
Grinding Mill Crushers
- Keep your equipment clean, preferably cleaning after each use. From heads to cables and hoses to the remote control unit, keeping your grinder clean will give you optimal usage for the entire life of the machine.
- Check for uneven wear on tooling, cracks, or other damage. This may be an indication of a damaged tool holder.
- Use OEM parts only.
- Pay attention to strange sounds, scratch patterns, power loss, or anything else out of the ordinary.
- Perform a deep clean on your mill weekly, breaking down the tips, checking for wear and erratic oscillation, belt slippage, and proper battery maintenance if applicable.
- Every 100 hours do a full breakdown and inspection, being sure to clean the mill and make sure everything is in proper working order.
- A yearly tune-up from a professional service provider will give you the edge when it comes to keeping your machinery up and running well.
Given the high-impact stresses experienced by crushing equipment, even slight damage can compound quickly. Keeping up with your crusher maintenance schedule is crucial to keeping your equipment running and avoiding unexpected downtime.
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