When producing large quantities of aggregate products, jaw crusher efficiency is critical. Crushing stone takes a large amount of energy and heavy-duty equipment. Both come with their own costs that you will weigh against the value they produce.
Jaw crushers are among the most common and powerful machines used in quarries for processing. These primary crushers are valuable for their output, as they can produce significant quantities of material. Here, we will explore how efficient they are and how to maximize their efficiency.
These are among the most powerful and reliable primary crushers and material processors in aggregate production, providing high productivity with low maintenance costs. These devices are most useful in breaking down larger pieces of concrete, asphalt, and ore. Jaw crushers are staples of the construction, mining, and recycling industries.
However, even these simple machines can have fine-tuning done to maximize output. With just a few changes, you can improve your jaw crusher efficiency! Contact us today for a quote!
Feeding Your Jaw Crusher
Jaw crushers are often choke-fed to maximize production speed. Choke feeding results in stone-on-stone crushing, which can help break apart more flaky materials. However, choke feeding also often results in a finer output. Trickle-feeding will result in larger products but also reduce capacity and jaw crusher efficiency.
In a perfect world, you would not change your feed rate often. Frequent changes will cause issues downstream and at any secondary processing plants in your workflow. Realistically, there will be long gaps between deliveries of feed material, resulting in intermittently choke-fed jaw crushers.
These crushers work best when producing uniformly broken particles for a secondary crusher, which occurs more naturally when choke-fed. A careful understanding of your crushing operation is needed to ensure crushing efficiency of a jaw crusher.
Improper feeding is a major cause of slowdown and production capacity gaps. These can be avoided by relying upon a well-trained operator, but some errors and issues arise from other sources. Bridging is one such slowdown that can be avoided via proper approaches.
Bridging is a common cause of inefficiency and time loss in quarry production. This event occurs when a stone enters the feed and becomes lodged, blocking the above material from entering. A single larger piece typically causes this, but several stones happening to wedge against each other may also cause a rock crusher’s inefficiency.
Stone blockage of this type is common and may take several minutes to resolve. Because of the large quantities and sizes of material passing through a primary crusher, this may cause several short tons per hour (STPH) to be lost. Depending on the maximum size of the material, this issue could cause several thousand dollars of loss every day.
Luckily, bridging can be avoided in several ways. First, training operators on how to monitor and manage incoming material for potential blockages. Second, ensure tools are on hand for operators to direct and orient oblong stones for smooth passage. Lastly, avoid oversized materials in the first place with tighter blasting grids.
Jaw Crusher Reduction Ratio
Either an 8-to-1 or 6-to-1 ratio should be the target reduction ratio for maximum jaw crusher efficiency. This setting typically provides an ideal P80 factor—when 80% of crushed material produced by primary crushing will pass screening after processing. A smaller closed-side setting will produce more fines.
On the closed side, settings will affect the nip angle. A nip angle of around 20 degrees is typically ideal for jaw crushers. Too large of an angle will prevent proper gripping and crushing within the chamber. Prevent boiling— slippage and not crushing—by keeping a tighter angle on the closed side.
Jaw crushers are typically used as a first step in aggregate production. If your secondary crusher relies solely on the production of a jaw crusher, your settings should be fine-tuned to the size and particle shape that you need. Choke-feeding also can help prevent longer material from passing through untouched by churning in the crushing chamber.
Another major benefit of fine-tuning the reduction ratio is that contaminants can be separated more easily. While jaw crushers are powerful and fairly general in use, getting the most out of a primary and secondary crusher will require some thought and attention to detail.
Tuning the Jaw Die Profile
Jaw crushers are versatile tools in no small part thanks to the interchangeable jaw dies. These differently shaped “teeth” come in many varieties depending on the material that will be processed in the crusher. Using optimal jaw die profiles will help avoid bridging and undue wear and tear to the crusher.
For example, flakier material should be crushed via jaw dies with more teeth to process it into more cubically shaped pieces. Alternatively, more abrasive stones might simply need a more durable jaw die to prevent frequent stops to replace them.
Ensuring operators are well-trained on the equipment will provide a critical source of information regarding the jaws. Frequent changing of the jaws is a major inefficiency, and operators will have insights into how to maximize the value of the equipment.
Jaw die profiles, and reduction ratio work together to improve jaw crusher efficiency and workflow. The options available to you for both will depend on the size of the crushing chamber and the crushing capacity of your machine.
Choosing the Right Crusher Size
On a base level, jaw crusher performance and efficiency are determined by the size and power of the machine. The volume of the crushing chamber and the width of the discharge opening affect how much material can be processed and discharged, affecting short tons per hour (STPH) that can pass through the system.
Matching the size of the machine to the work involved requires careful consideration of material size, quality, and type. A jaw crusher that is too large might not crush material evenly. Larger machines also require larger engines, which may be more costly to run when compared to the STPH. The operation and size chosen will have foundational impacts on the efficiency of a jaw crusher.
Jaw crushers are used across several industries, including mining, recycling, and construction. Their size and power make them very useful in reducing portions of concrete, asphalt, and ore into more manageable pieces. As a primary crusher, they are useful in tandem with secondary and tertiary processing devices.
Proper Maintenance and Use for Jaw Crusher Efficiency
One of the largest losses of a crusher’s efficiency is stoppages for repair. Operators should be trained on how to work these devices properly, but many misuses or maintenance processes might be overseen. Some of these include:
- An annual check of the main frame bearings should be done and recorded to track bearing wear.
- Periodically check the oil to ensure a properly lubed bearing housing.
- Conveyors and under crusher hoppers beneath the discharge should be wider than the discharge itself.
- Avoid crushing oversized material against the barrel of the jaw.
While improperly feeding a jaw crusher is possible due to the size of the feed material, it should be noted that it is rare for a jaw crusher to be fed to capacity. This is because jaw crushers typically feed into secondary processing that will have a smaller capacity.
When properly maintained, the crushing efficiency of a jaw crusher can achieve production rates that will outshine most other crushing machines.
Are You Ready to Get the Most Out of Your Jaw Crusher?
There are many ways to fine-tune jaw crusher efficiency and production. However, ensuring you have the right machinery for the work at hand is a major first step towards maximizing your productivity. Here at Kemper Equipment, we offer excellent service and expertise to the aggregate, asphalt, and coal processing industries. We offer more than just equipment. We offer quality, performance, and long-term confidence in your business’s future.