Cost-effective aggregate production begins with employees who are knowledgeable about the maintenance requirements and operational parameters of the cone crushers they operate. There are certain proven methods and practices industry experts use to ensure a smooth crushing operation. This article presents key tips that will help you maximize your cone crushing operation.
1. Operate at a consistent closed-side discharge setting. Producing a consistent product quantity, quality, uniformity and attaining a balanced circuit begins with operating the cone crusher at a consistent closed-side discharge setting. If a crusher is allowed to operate at a wider-than-optimum setting for even a short period of time, the result will be less product and an increase in oversized material.
Keep in mind that oversized product almost always creates circuit flow problems within the aggregate plant. An example of the effect that crusher setting has on the product gradation is as follows: If the target crusher setting is 3/8 in. (10 mm) but the setting is not checked and it wears open to 1/2 in. (13 mm), then the end result is a 15 percent decrease in the minus 3/8-in. (10 mm) material size. This is a substantial decrease in productivity.
Most aggregate producers would be amazed at the revenue lost each year due to the simple fact that crushers are not being operated at consistent closed-side settings. The crusher setting should be checked on a per-shift basis.
2. Operate at a consistent “choke-fed” cavity level. If a crusher operates at varying cavity levels throughout the shift, the result will be an inconsistent product shape and inconsistent production rate. Operating a cone crusher at a low cavity level (half cavity) will result in a significantly coarser product gradation, and this low cavity level will also produce more flat and elongated product particles.
Efforts should be made to operate the crusher at a proper choke-fed cavity level, as the favorable end result will be increased crusher throughput tonnage and a more cubical-shaped product. This tip is particularly important for the tertiary (short head) crushers in the circuit, as they produce the vast majority of an aggregate operation’s salable products.
3. Do not trickle feed the crusher. Trickle feeding a cone crusher should be avoided because it not only results in poor productivity and poor product shape, but it can also adversely affect bearing alignment within said crusher. Due to the operational characteristics of a cone crusher, when crushing, it should never be operated below 40 percent rated horsepower. To obtain a proper “loaded bearing alignment” and to maximize productivity, the crusher should be operated above 40 percent rated horsepower yet below 100 percent rated horsepower of the drive motor.
A power draw of 75 to 95 percent is a great target range to stay within while crushing. Excessive power peaks, particularly above 110 percent rated horsepower, should be avoided as this could lead to premature crusher failure.
4. Ensure the feed is evenly distributed. The incoming feed material should be directed on a vertical plane into the center of the crusher. When the incoming feed is not directed into the center of the cone, one side of the crushing cavity could be quite full while the opposite side of the cavity could be low or empty. This will always result in a low crusher throughput tonnage, the production of more flat and elongated product particles and oversized product.
This typically prompts crusher operators to tighten the crusher setting in order to get the crusher to make the smaller product size that they are trying to produce. This in turn can result in an overload condition in the form of adjustment ring movement on the side of the crusher that is heavily loaded. Over the long term, this can cause the adjustment ring to become tilted on the main frame, resulting in an even larger loss of productivity.