Every producer wants peak crushing performance, but not every producer knows how to achieve it. Getting there may require just a few tweaks – or even a total rebuild. To remain at peak levels requires proactive maintenance practices, combined with expert consultation and continuing education.
When operations truly maximise cone crusher performance, the perennial paybacks include:
-
Lower cost per tonne.
-
Greater plant uptime.
-
Increased production capacities of highly saleable material.
-
Reduced maintenance and wear costs.
“Maximum cone crushing performance requires a complete understanding of the application parameters, the design limitations of the crushing machine and the processing circuitry needed to support that machine,” Mike Schultz, crushing product manager for Superior Industries, said at the launch of the company’s high performance Patriot cone crusher series.
Schultz brings more than two decades of crushing industry experience to the company’s veteran team of crushing product, parts and service professionals.
“Our mission is hands-on expertise, innovative engineering and working closely with producers and operators to fine-tune their crushing operations for long-term efficiency,” he said.
Defining parameters
The cone crusher is a versatile machine that can be used in all phases of material reduction – from the rock face to product finishing – but, more often than not, its duties are targeted at secondary, tertiary and quaternary aggregate and mining applications. A cone is a compression crusher that effectively crushes abrasive material, plus a wide variety of stone from medium to very hard compressive strength.
{{image2-a:r-w:300}}How can the cone deliver the most value while minimising operating costs per tonne?
From a bottom line standpoint, Schultz said maximising performance and cutting wear costs meant “getting every stone through that cone crusher that we safely can – while preventing any machine damage – and still meeting or exceeding production goals”.
From the basics to the big picture, Schultz said the following solutions and strategies would maximise cone crusher performance.
Whether specifying a new machine or finetuning an existing crushing circuit, all key parameters must be defined upfront.
“What is the true work that you’re asking that crusher to do?” asks Schultz.
As part of the key parameters:
-
Operations must provide data on proper feed gradation, desired output gradation, tonnage requirements and, most importantly, the material type.
-
Knowing the precise composition, compressive strength (maximum force that material can withstand before breaking) and chemical properties of the stone is a huge factor in determining how much work a cone crusher needs to do.
“Many operations try to do too much with one machine, pushing it beyond its design limitations and causing excessive component stress and wear, and the potential of serious damage,” Schultz said.
All crushers are designed with certain reduction ratio limitations. In most cases, cone crushers provide reduction ratios of 4:1 and up to 6:1 (meaning the ratio of the feed size to the crusher versus the size of the crusher discharge).
“The reduction ratio design limitations and the rated capacity (tonnes per hour) of the cone crusher are the most important factors to consider when designing a crushing circuit – and determining how much that crusher can safely do,” Schultz said.
With complete application data in hand, Schultz said it was important for operations to work closely with their crusher supplier to select the right crusher.
The key considerations are:
-
Crushing speed.
-
Chamber design.
-
Liner configurations.
-
Crusher settings.
“There are myriad choices of machine configurations,” Schultz said. “Whether it’s minimising fines or maximising fines, or trying to create the highest yield of a particular product, there are chamber and liner configurations designed specifically to meet the desired product yield.”
Tap into automation
For performance efficiencies, proper circuitry should be designed around the cone. Significantly, the circuit should be engineered to provide the cone with choke-fed material, or enough material to keep the crusher full.
{{image3-a:r-w:300}}Having too little feed can cause the machine to side load, which stresses components. Also, having too many fines in the feed leads to premature wear issues.
Having adequate screening capacity downstream of the crushing circuit is another key factor. In a closed circuit set-up, material that is not properly sized is recirculated to the crusher for further reduction.
“It’s very common to see operations that have a bottleneck at the screening circuit,” Schultz said. “They do not have enough screening capacity, so properly crushed material is sent back to the cone. These unnecessary recirculating loads simply eat up more space and wattage in the crusher while increasing wear.
“To significantly affect cone performance, automation doesn’t need to be over the top and super complicated, but rather quite simple and very easy to control.”
Schultz said the biggest thing automation delivers is protecting the machine from damage via a warning system that alerts operators to conditions such as bowl float, excessive amperage or temperatures, and lubrication or low flow oil issues.
Schultz pointed to Superior’s Patriot cone series, which features a three-sensor “bowl float” or “ring bounce” monitoring system that alerts the operator if conditions exceed the cone design’s limitations.
He said hydraulic cylinders basically hold the cone’s top and bottom together.
When the crushing action on the cone exceeds the pressure that is holding those two pieces together, it causes bowl float or ring bounce, which is any movement (even slight) between the top and the bottom of the crusher. Undetected bowl float will eventually lead to component failures.
“When operating a cone, preventing bowl float is arguably the single most important thing you should ensure,” Schultz said.
Most cone crushers are designed to open due to tramp metal or an uncrushable situation. They are not designed to operate under normal conditions with ring bounce.
“There should be zero ring bounce or bowl float under normal operating conditions. Without an automation package, it can be difficult to detect ring bounce at times.
“You can literally be standing on the machine, and you cannot detect even the slightest ring bounce – so having that automated warning system is an enormous advantage.”
{{image4-a:r-w:300}}Schultz also encourages operations to tie an automated warning system into the designed amperage utilisation of the machine.
“Our automation package works in conjunction with the drive motors and essentially reads the amp draw of the machine. If the motor and the machine are being overworked, the system will either take steps to reduce the amp draw, or will send an alarm to the operator.”
Automation features are also designed to maximise the life of wear components.
For example, the Patriot cone’s automation package includes auto-wear compensation. As liners wear, the crusher is designed to automatically compensate for that wear, to maintain the same settings in the machine.
With liner wear, the space between the two compression components expands. At the same time, the auto wear compensation system automatically closes the machine down to maintain proper settings throughout the life of the wear components.
True limiting factors
One of the major misconceptions Schultz encounters in the field is the way operators may view the closed side setting (the material discharge opening from maximum to minimum) of the cone.
Operators often try to maintain a specified closed side setting (CSS), assuming they will yield the desired product output no matter what. Often they close the setting down to the smallest point possible, and then let the machine beat itself up.
Schultz suggests a better approach to setting up a cone for maximum performance:
-
First, consider that the true limiting factors of any cone crusher are attached power and crushing force.
-
After determining the proper speed and liner configuration, it is possible to “dial in the proper settings of the machine” based on maximising the amp draw to a desired set-point – while making sure the machine does not incur ring bounce at that point.
-
Throughout its life cycle, a cone crusher needs to withstand daily abuse. Operators should practise the following to optimise crusher performance:
-
Investing in high quality equipment and components upfront will save big bucks over the long haul.
-
Next, maintaining ongoing preventative, predictive and reactive maintenance programs are an imperative to optimum plant availability and minimised maintenance and wear costs. The proper training of personnel is also key to overall performance and efficiency, and especially to consistently safe operation.
-
Lastly, operations should partner with crushing experts and equipment suppliers who are accurate, accessible and willing to offer hands-on, on-site troubleshooting, service and parts support over the total life of the machine. That is proper machine life cycle management, and that is what ultimately ensures maximum cone crusher performance.
Superior Industries, based in Morris, Minnesota, USA, supplies bulk crushing, screening, washing and conveying solutions for the construction, aggregates and mining sector globally. Its crushing products include the Patriot cone crusher, the Liberty jaw crusher and the Valor vertical shaft impactor, in static and mobile configurations. Superior Industries’ Australian distributor is 888 Crushing and Screening Equipment.
Source: Superior Industries