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Recycling, Screens & Feeders, Processing, Maintenance

Articles from CRUSHERS PLANT & EQUIPMENT (676 Articles), SCREENING PLANT & EQUIPMENT (609 Articles), FEEDERS/FEEDING EQUIPMENT (317 Articles)












The original rubber and self-cleaning wire screens suffered from blinding and build-up of crushed fines.
The original rubber and self-cleaning wire screens suffered from blinding and build-up of crushed fines.

Recycler reports productivity, payback after screen changeout

A concrete recycler estimates its daily output has risen 10 per cent since replacing its blinded screens.

Robert Hill, the crushing consultant and site manager of a 550,000 tonnes per annum concrete recycling operation had to stop his 220 tonne per hour (tph) concrete recycling plant every day to clean blinded screens, often losing three or more hours of production from his 6m x 2m triple-deck horizontal screen.

The top deck of the screen was fitted with 12mm apt woven mesh cloths being fed at a rate of 220 tph. The top deck woven mesh stayed relatively clean most of the time.

Around 130 tph passed through the top deck cloths to the 8mm apt middle deck woven mesh cloths. Some blinding occurred from time to time on the feed end, with only the occasional need for cleaning.

The bottom deck was where the real problem lay. Two 4mm x 25mm slotted apt rubber screens were fitted to the feed end followed by 4mm apt self-cleaning wire screens.

The combination of rubber and self-cleaning wire screens suffered quite badly with blinding and build-up from crushed concrete fines. It was so severe that the plant would have to be shut down every two to three hours for screen cloth cleaning, often resulting in up to four hours of lost production out of the 10-hour production day.

The stainless steel Type S Flex-Mat screen cloth upon installation.
The stainless steel Type S Flex-Mat screen cloth upon installation.

“In all my years I’ve never seen anything like it,” Hill said when he first contacted screen media supplier Nepean Rubber for help.

Hill arranged for a Nepean Rubber representative to inspect his screening plant and offer recommendations to solve the screen blinding and lost production problems.

A screening performance assessment was undertaken in the early hours of the morning, prior to the commencement of crushing for the day. An assessment involves close inspection of the screen media and screen box condition, inside each deck where internal access is possible.

The vibration of the screen is vitally important to the performance and vibration monitoring is usually included in the free service. An assessment on a screening plant of this size usually takes an hour or two, perhaps a little longer when vibration monitoring is included.

A report on the screens was compiled, including recommendations to solve the bottom deck blinding problems, along with other suggestions for overall improved screening plant performance.

To resolve the blinding issues on the bottom deck of the horizontal screen it was recommended that Hill install up to two highly flexible Nepean Ultra Flex thin membrane rubber screens, followed by stainless steel Type S Flex-Mat self-cleaning wire screens.

The replacement stainless steel screen cloth captures oversize material with ease.
The replacement stainless steel screen cloth captures oversize material with ease.

Hill followed the advice given and purchased a full deck of the stainless steel Flex-Mat plus two Ultra Flex rubber screens.

Even though the Ultra Flex rubber and stainless steel Flex-Mat screen cloths were at a higher price point than the original screens the investment in the high performance screen media was insignificant compared to the cost of lost production and downtime.

One Ultra Flex rubber screen cloth was fitted in the position #1 feed end with the stainless steel Flex-Mats screen cloths in the position #2-#5 feed end.

Since the installation of the Flex-Mats and Ultra Flex rubber screen cloth, Hill has been able to run his screen non-stop all day without ever requiring stoppages for cleaning.

“The screens are never touched during the day and sizing is perfect,” Hill said. “All we ever have to do is give them a bit of a tidy up of an evening.”

Without downtime for cleaning, Hill estimates he produces about 600 tonnes more saleable material per day. He made up the cost of the complete deck of screens plus spares in less than one and a half days of production.

Source: Nepean Rubber & Plastics




















Monday, 24 September, 2018 01:58pm
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