The output size of a jaw crusher does not remain the same when its settings change. One of the key factors affecting the discharge size is the Closed Side Setting, or CSS, which determines the size of the crusher’s discharge opening. A smaller or larger CSS can make the output finer or coarser, directly affecting downstream crushing and screening. So, how does CSS affect jaw crusher output size, and how should it be adjusted?
I.How Does CSS Control Jaw Crusher Output Size?
1.A Smaller CSS Produces Finer Output
When the CSS of a jaw crusher is reduced, the jaw crusher discharge opening becomes smaller. The crushed material must therefore pass through a narrower opening before leaving the crushing chamber. As a result, the jaw crusher generally produces a finer discharge, with a higher proportion of smaller particles. A smaller CSS can be useful when a crushing plant requires a smaller jaw crusher output size for secondary crushing or screening. However, CSS should not simply be reduced as much as possible. The appropriate jaw crusher setting should be selected according to the required discharge size and the overall production requirements.
2.A Larger CSS Produces Coarser Output
When the CSS is increased, the jaw crusher discharge opening becomes larger, allowing larger particles to pass through more easily. The jaw crusher output therefore tends to become coarser. This can be suitable when a larger discharge size is acceptable for the next stage of the crushing process. In a primary crushing plant, the jaw crusher setting should also match the feed requirements of downstream equipment to maintain a stable crushing process. Therefore, adjusting CSS is an important way to control jaw crusher discharge size and produce crushed material that better meets the requirements of the following crushing and screening stages.
II.What Happens When CSS Is Set Too Small or Too Large?
1.When CSS Is Too Small
A jaw crusher with an excessively small CSS will generally produce a finer discharge. However, a smaller jaw crusher setting is not always better. If the required jaw crusher output size is relatively coarse, setting the CSS too small may produce more fine material than necessary and change the feed conditions for downstream crushing and screening equipment. This can make it more difficult to maintain the desired product size distribution. Therefore, CSS should be selected according to the required discharge size rather than simply being reduced to achieve finer output.
2.When CSS Is Too Large
An excessively large CSS can result in a coarser jaw crusher discharge, with more oversized particles entering the next stage. If the secondary crusher or screening equipment requires a smaller and more consistent feed size, this can affect the performance and stability of the downstream process. For this reason, the jaw crusher discharge setting should be matched with the requirements of the entire crushing plant, rather than adjusted independently.
III.How Should You Adjust CSS for the Required Output Size?
Start by determining the required jaw crusher output size and the feed requirements of the next crushing stage. Then adjust the CSS accordingly and check the actual discharge during operation. If the output is too coarse, reduce the CSS; if it is finer than required, increase it appropriately. After adjustment, check the discharge size again and fine-tune the setting if necessary. Keep in mind that CSS determines the discharge opening size, but the jaw crusher produces a range of particle sizes rather than one fixed output size.
FAQ:
1. Does a smaller CSS always produce better jaw crusher output?
No. A smaller CSS generally produces finer output, but it may also reduce throughput and increase the crushing load. The CSS should be selected according to the required product size and the requirements of the downstream crushing process.
2. Why is my jaw crusher output getting coarser even though the CSS has not changed?
Jaw crusher output can become coarser as the jaw plates wear, because wear can change the effective crushing chamber profile and discharge condition. If the product size changes during operation, check the jaw plate condition and verify the actual CSS.
