Evolution of the volumetric capacity of cone crusher liners

Difference between new and worn cavity

Let’s look at this through the images below. These show a cross-section of crusher liners under two conditions: on the left a new profile without any wear and on the right, the same profile worn in use. Thicknesses in the worn profile indicate a utilization rate of over 50%, so we can estimate that it was removed at the right time. Note that both profiles keep the CSS (close side setting) at 40 mm, but we can see that the top size of 112 mm is located outside the crushing zone in the worn profile, and the the worn cavity measures 84 mm. 

To better comprehend the volumetric capacity, it is highlighted in both profiles in the following images. We can see that there is a decrease in capacity in the worn profile. Having a lower volumetric capacity, the cavity will process fewer tons per hour compared to a new part. This comparison must be made to the same CSS (in this case 40 mm), because if we increase the CSS of the worn profile, the volumetric capacity could be recovered, but it would decrease the quality of the product.

Profile performance and productivity

The useful life of a profile can roughly be divided into three phases in terms of productivity:

1. Initial phase

It has been observed that most of the time, the new liner starts at 80% of productive capacity. This continues for a short period of time while the cavity becomes adjusted to the operating conditions.

2. Intermediate phase

This phase begins once the profile is adapted to the grain size, CSS, and tonnage, and the operating parameters stabilize within the safe ranges. During this phase, the production capacity is closer to 100% capacity for a longer period than in the first phase.

3. Decreasing phase

It has been estimated that this phase is reached once the wear on the profile reaches 50% by weight. At this stage it is recommended to change the liners, as the reduction of the volumetric capacity triggers an accelerated decline in productivity.

Final recommendations

• Keep a log of the weights of the worn parts to obtain optimal utilization rate, which should ideally be between 45% and 55%
• Take into account the formula to calculate the utilization rate:

        U.R. = (Weight of new part-Weight of worn part) × 100 / (Weight of new part)

• Monitor and follow tons/ hr production.
• Identify how much tons / hr decreases when reaching the 50% utilization rate of the wear parts. If this value is above 10% loss of tons / hr, it is recommended to change the liners.
• It is important to assess whether continuing to use the liner above 50% U.R. compensates for the loss in tons/ hr that will be produced. This loss in tonnage is immediately compensated if liners are replaced with new ones.