How to best maintain the right crusher settings

By |  April 2, 2024
Jarrod Adcock

Adcock

Why is selecting and maintaining the proper jaw crusher closed-side setting (CSS) so important to crushing efficiency? 

Jarrod Adcock, crushing product manager at Superior Industries, explains.

“The right jaw crusher closed-side setting directly affects the flow of the rest of the crushing circuits, allowing the primary jaw to produce material that’s ideal for secondary crushing,” says Adcock, who is part of Superior’s rockface-to-loadout solutions team.

Follow CSS basics

For those new to crushing, a jaw crusher’s CSS is the distance between the jaw liners at the bottom of the crushing chamber when the machine is operating. 

The CSS determines the product size of the material produced by the jaw crusher. By consulting with a crusher manufacturer and a machine manual, producers can pinpoint the right CSS for their primary crusher and for the circuits to follow. 

As Adcock describes, selecting and maintaining the right CSS impacts the overall flow of material – plus production capacity, product gradation, power draw and wear.

Crushed material that is similar in size to the closed-side setting offers the best particle shape. Photo: Superior Industries

Crushed material that is similar in size to the closed-side setting offers the best particle shape. Photo: Superior Industries

Control feed size and fine materials

Additionally, feed material and crusher settings go hand in hand with crushing efficiency.

Adcock advises operators to make sure the feed size is correct for their crusher and to eliminate fines from being fed into the jaw. By pulling out fines, operators will ensure processing efficiency and yield a higher quality material at the discharge point. 

Crushed material that is similar in size to the CSS offers the best particle shape, Adcock adds, while material that is smaller than the CSS contains more elongated particles because it passes through the machine without being crushed. 

Fortunately, proper scalping helps to remove fines from the feed material. 

“When we design a primary jaw circuit, we normally place a grizzly feeder ahead of the jaw crusher to pull out the fine materials,” Adcock says. “That’s why it helps to work with a manufacturer who offers all the components of a plant and understands optimum material flow from one circuit to the next.”

Maintain the desired settings

Maintaining the correct crusher settings supports plant productivity, as well. 

Consider the example of an operator who neglects daily CSS monitoring while dealing with the issue of excessive liner wear. As liners wear, the CSS expands. 

That means the material going to a secondary cone crushing circuit keeps getting larger. The material may overload the cone, and if the operator “opens up” the cone to accept larger material, this will directly affect the efficiency of the tertiary circuit. 

It becomes “a domino effect of lost production efficiency,” Adcock says.

So, producers should check the CSS daily and inspect the liners around the same time, living by a two-birds-with-one-stone maintenance approach.

A jaw crusher’s closed-side setting is the distance between the jaw liners at the bottom of the crushing chamber when the machine is operating. Photo: Superior Industries

A jaw crusher’s closed-side setting is the distance between the jaw liners at the bottom of the crushing chamber when the machine is operating. Photo: Superior Industries

Streamline CSS adjustments

While older-style crushers require time and labor to change settings via a manual shim adjustment, modern crushers are easier to manage with two ways to make setting adjustments. 

The first option is a hydraulic-adjusted wedge system that operates with the push of a button. As the opposing wedges go against one another, the hydraulic cylinders open or retract the CSS, making it a simple operation.

The second option is the use of a hydraulic toggle plate, which eliminates the opposing wedge system while adding hydraulic cylinders to the backside of the crusher to operate the CSS system. The hydraulic system will react to a tramp event or to excessive force, and the cylinders will retract the CSS, letting material pass through before returning to the original setting.

Final thought

Optimizing crushing efficiency at the primary jaw crushing circuit leads to similar performance in the circuits that follow, delivering greater productivity, profitability and the lowest cost per ton.

Carol Wasson is a veteran freelance writer for the aggregate and construction equipment industries.

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About the Author:

Kevin Yanik is editor-in-chief of Pit & Quarry. He can be reached at 216-706-3724 or kyanik@northcoastmedia.net.

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