In response to the needs of our customers, FLSmidth has developed a hydraulic rolling frame assembly to reduce screen change-out time in typical roll-in/roll-out screen installations. This design allows a complete screen change-out to be carried out in less than 60 minutes.
When screens are used in SAG mill applications, the quick change-out process of the FLSmidth rolling frame eliminates the need to stop the mill to carry out basic screen maintenance. Considering that the down-time cost for a SAG mill is usually more than US$140,000/hour and that a typical screen replacement could take up to 24 hours, the use of the hydraulic screen rolling frame represents a significant cost saving and provides an increase in plant availability.
“SAG mill circuits are very capital cost intensive, and production/uptime is key to achieving a reasonable payback period on investment," said Eddie McKerr, FLSmdith Global Product Director – Screens. "A number of our clients have challenged us to find a solution to lengthy shutdown periods and loss of production, which can run into hundreds of thousands of dollars per hour. Streamlining the screen change-out process as we have done here adds significant value to the client in real money terms.
"This is a perfect example of how our team has delivered a genuine solution by listening to our customers.”
The rolling frame was entirely designed and engineered in FLSmidth’s global screens technology center in Australia. The project was founded by FLSmidth’s R&D program and used advanced finite element analysis and modeling tools to provide a robust and reliable design. Extensive in-house testing ensured that a successful solution was provided for the customer. The main principles in designing the rolling frame were to increase safety of the change-out operation, minimize downtime and create a “one-man operator” solution. The end design is an example of FLSmidth’s continued focus on innovation and finding the solutions to our customers’ needs through investment in product development.
“The design was challenging, and a number of innovations have been incorporated in the final solution to ensure the customer is provided with a complete turnkey system," said Tony Elliott, Engineering Manager – FLSmidth Australia. "The design focuses on being safe and easy to operate compared to more traditional methods. Features like the remote control pendant, fail-safe controls and incorporated maintenance platforms will make the hydraulic rolling frame a desirable product for sites looking for safe sustainable solutions that will greatly improve plant efficiency through the reduction in plant down time.”
Each rolling frame contains its own programmable logic controller (PLC) and hydraulic unit that allows the screen and frame assembly to disconnect from the supporting pedestals, lift up and drive out of the operating position along a twin parallel rail arrangement into a maintenance area prepared for servicing the screen. The standby screen is then driven into the operation position, and the plant can continue with normal production.
This entire change-out process is controlled by a user-friendly wireless remote control. The operation can be done at a safe distance from the moving equipment and without direct human interaction.
Each pedestal is equipped with an automated locking mechanism to ensure the frame is secured to the supporting structure. This is particularly beneficial in installations subject to seismic reactions.
Both the drive arrangement and spray bar assembly are mounted directly to the rolling frame. Two flexible hoses with Camlock couplings provide the water supply for the spray bars, and the simple disconnection of these is the only direct interaction required with the machine to complete the change-out process. No tools, mechanical works or cable disconnections are necessary. The screen is ready to drive out at all times.
Interlocks and sequential logic programmed into the PLC allow safe operation of the rolling frame. A collision detection device ensures the screens cannot run into each other, and additional positioning sensors ensure the machine is at the correct location for maintenance or operation.
For added safety, lights and audible signals are used to indicate normal operation and malfunction alarms.
“Having witnessed how complex and labor-intensive it can be to replace a whole screen on site, the hydraulic screen rolling frame revolutionizes this process by eliminating the need for large, expensive cranes, long shutdowns and large crews to do a screen replacement," said Cristobal Brant, FLSmidth Product Specialist –Screens. "An entire change-out can be safely completed in less than an hour with a single-man operation.”
CONTACT: Cristobal Brant