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OFS, Lincom are making filters smarter

Filter presses aren’t rocket science – they’re made up of a simple set of plates, cloths and a pump, but OFS has found a way to make them smart.

Filter presses are a relatively straightforward machine, generally used in quarry dewatering applications to remove fine sands and clay particles from a thickened flow stream created by washing and screening.

The filter’s plate pack, most commonly formed by recessed chamber filter plates, is arranged in a supporting structure and is compressed by a hydraulic cylinder. Filter cloth is mounted on each plate, which forms a filter chamber by the recessed body.

Slurry can then be pumped through a feed channel into the filter chamber. Solids remain on the filter cloth while the liquid departs through the drainage system of the filter plate.

Continuously feeding the press raises the solid concentration in the filter chamber and the pump head pressure, which in turn reduces the flow rate of the slurry. This is maintained until a cake with the required solid content is formed. Finally, the filtration pressure is released, the plate pack is open, and the filter cake is discharged.

Alan Dunbar, Lincom product manager for OFS, said the process is preferable to creating a lagoon or tailing facility.

“Ultrafine material stored in tailings facilities or lagoons are highly susceptible to flood and earthquake, but the operators are also actively removing their own water storage buy ultimately filling the lagoons with material, or paying to dump wet slimes,” he told Quarry. “Lagoons also need permits and may require permanent care. It’s a big area of land that you will eventually have to deal with.”

“With a filter press you can extract dry, stackable product. In many instances the filtrate and/or solids can both be reproposed.”

The OFC filter presses create very clean water. Image: Lincom

What elevates the OFS produce range is the integrated automation. The entire machine is controlled by a programmable logic controller (PLC) which communicates with the range of sensors allowing individual customisation of each system.

The system uses sensors to measure pressure and flow, slurry levels and monitor safety systems which it can then use to determine when the machine should cycle.

Dunbar said “they often incorporate automated high-pressure cloth washing, which makes maintenance much easier.

“The more blind your cloths are, the less chance the filter press will work to its potential. Traditionally, washing the cloths would need to be done manually – and if you have a press with over 100 plates the idea of manual washing them all is a nightmare,” he said.

“The automatic washing is also much faster, meaning there’s less overall machine downtime and manual handling.”

A filter press can extract dry, stackable product. Image: Lincom

Sensors can also automatically detect the capacity of the slurry tank and height of the cake pile and turn things on/off where required, allowing the machine to operate around the clock. It can also integrate with automating conveying systems if a site wants to convey or stockpile the material.

Safety systems have also been automated. If anyone attempts to interfere with the filter press while it is in operation, it will automatically shut down. It also comes with control system and guarding to Australian Standards ensure nobody can get hurt if something goes wrong.

Dunbar said the most important part of operating the filter press happens before it is even installed.

“It’s vital to find out exactly what will be filtered through the press to ensure it’s the right one for the job,” he said.

“We visit our client’s sites and work with them to get a good understanding of the operation. They’re producing a big bowl of soup with all kinds of stuff in it – and if you don’t know what’s in the recipe, you’re in trouble.”

“The key to finding the right filter press is the testing phase. If you just buy a filter press off the shelf and cross your fingers it might work fine, or you could just end up with a machine that makes mud.”

Lincom has a scale testing lab onsite in its Narangba office, as well as a site portable testing unit. To ensure the filter press will work with the customer’s site, the company collects samples from the customer and tests in the lab.

The Brisbane-based lab can provide detailed analysis but more importantly, a real filter press is used to run trials on customer samples.

Dunbar said the equipment is manufactured to a high-quality, German standard.

“Everyone on the design team at OFS lives and breathes filter presses – they’ve spent their whole careers working with them,” he said. “Backup and support are vital in the quarrying industry, and that starts with having a focus on analysis and education over sales techniques”.

Lincom has offices around Australia and holds OFS stock locally. That means if a press does fail, the company can provide the parts needed quickly.

The company plans to promote the OFS equipment range over the coming months, highlighting the benefits to the quarry sector.

Dunbar said the team has planned presentations with the Institute of Quarrying Australia (IQA) and will be attending several trade shows during the year.

“The OFC filter presses create very clean water that can go straight back into a wash plant and a repeatedly dry cake,” he said.

“The enhanced automation makes them more reliable, more efficient, and easy to use.”•

For more information, visit lincom.com.au

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