In the past, aggregates plants were mechanical in nature, with plant operations such as crushing, screening and conveying functioning separately and manually. Over the past two decades, however, automation has provided a two- to 10-time increase in productivity in many different aspects of an aggregate plant's operations. But one thing is certain: the process of making little rocks out of big ones has not changed. Automation and computer technology have simply provided the industry with the high-tech tools needed to make greater productivity possible.

While large firms may dominate the technological arena in the aggregate industry, smaller, innovative companies are also getting in on the act. Many companies now find that the ideas they once implemented with a cutting torch and welder can be accomplished with the use of software, computers, sensors and communications equipment.

Who would have thought that an aggregate company's main office could monitor an entire plant's production right on a computer screen, or that a manager could pick up daily tickets off of the internet and have them waiting in the office each morning, without a single person attending to the work? This again adds credence to the argument that the automation of certain processes provides the means for the labor force to handle more volume within the same amount of time.

One unique aspect of the aggregate industry is that if you, as the operator of an aggregate site, want to try something new, you can implement the change and see the results immediately, for better or worse. Some of the best ideas come from the field or from time spent touring someone else's plant. It is hard to tour someone else's plant without coming away with a tip to try at your own site.

Advances in cone-crusher automation

Getting an edge up on the competition means increasing productivity while keeping operating costs down. To mining and aggregate producers, this means maximizing crusher operation and minimizing downtime. Achieving this goal requires a high degree of control and automation.

Ideally, an automation system uses proven process control technology to optimize crusher performance while protecting the cone crusher against overpower, overload and overforce. Such a system should also be user-friendly, allowing operators to easily monitor and control crusher station parameters.

Serving aggregates customers

What is automation? It is set of devices, systems and operating rules eliminating the need for human decision and intervention, within a given operating frame.

The four main functions of automation are to monitor, control, record and communicate. The automation system monitors every important parameter for the crusher, including internal bearing temperature, crushing force, power, crusher setting, lubrication pressure, temperature, and filter condition, material level inside the cavity.

Ideally, an automation system looks at all of the above parameters and will give the operator alarms and warnings before taking corrective action giving the operator time to prepare for a shut down or maintenance day. It is possible to automate every aspect of the crusher and crusher station.

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Controlling the lubrication system ensures that the air blower, immersion heaters, lube pump and oil coolers will continually work together to give the crusher the proper degree of lubrication for maximal operating efficiency. Monitoring the hydraulic system informs the operator of potential problems that may result from solenoid faults, leaks in the lines, or excessive repressurization The crusher drive motor is protected by the automation system against overload and starter faults. If power is too high, the system automatically takes corrective action.

Low choke levels not only mean lost production, but reduced product quality. High choke feed and an even load ensure a high level of interparticular crushing, achieving the best product shape. The crusher automation system must be configured to achieve excellent feed control. By monitoring the cavity level and power draw, it's possible for an automated system to adjust the feeder to optimize both set points. This ensures a high choke level, which results in the most productive and costefficient yield.

Automatic setting adjustment control eliminates the need for continuous human surveillance, which saves money by reducing costly staff time. There are three important control modes that every system should have: manual, auto setting and auto power.

Manual mode gives the operator complete control of the crusher station, including opening and closing the crusher and starting and stopping the feeder.

Auto setting mode maintains the crusher at the desired settings, while protecting it from over force and over power conditions.

Auto power mode also protects the crusher from these conditions, while automatically adjusting the crusher setting to maintain power draw due to liner wear.