Plant & Equipment

Designing screens for C&D applications

As many of these materials can be recycled and re-used in applications such as construction projects and road drainage, there is a great demand for systems that can effectively remove valuable product from C&D waste.

Materials washing specialist CDE Global identified the need to create a pre-screening unit that could process C&D materials. The outcome is the R1500 primary screening unit, with a capacity of up to 250 tonnes per hour. The R1500 combines a feed hopper, a P1-36 Infinity screen and conveyors, and can be fitted with either a belt feeder or apron feeder.

“An essential element of an efficient plant is getting the feeding system right, so we spent a number of years developing the R-range of primary screens,” said CDE’s R&D engineer Stewart Cusick, the R1500’s lead designer.

“We identified that more challenging materials such as C&D waste needed an advanced system to handle the demands of the material, which can have high fines content and contain sticky clays as well as large pieces of concrete, blocks and other stonework, which needs to be removed prior to delivery to the washing plant.”

Robust trials

In early 2015 the R1500 was put through extensive testing on eight sites across the UK, trialling a wide range of C&D materials and heavily clay-bound hard rock from quarries. This stage of development included G-meter testing, amp readings, stress analysis and modal analysis. The motors were verified under maximum load conditions.

The 5.5-tonne apron feeder has been designed to accept excavated materials including metals, heavy rock and rebar concrete. There is also the option to increase the feeder to seven tonnes when fitting the optional extendable hopper sides. To adapt to confined sites, the hopper can be loaded from three sides. The oversize screen has a chevron belt ideally designed for C&D materials.

The R1500 has been designed with safety in mind, with all nip points covered with guarding that meets global safety and design standards. The side walls have been raised to prevent material falling from the top deck screen. The 800mm walkways ensure it is safe and easy for operators to access the plant, to carry out inspections and maintenance.

There are low running costs, with only 24.5 kilowatts of power needed for initial start-up.

“The R1500 is very efficient,” Cusick said. “It runs on 16.5kW for a 200 tph plant.”


Stronger, lighter design

The R1500 includes the 2.4m x 1.5m Infinity P1-36R screen. With apertures up to 100mm, it is equipped to handle all C&D materials. A common issue for the industry is pegging. This is not a problem for the R1500’s P1-36R infinity screen, because the design process and testing have ensured the screen does not peg.

“The Infinity screen includes design features such as the Rosta suspension mounts, which deliver 98 per cent vibration isolation, ensuring protection for the supporting structure and the most efficient transfer of energy to the screening material,” said CDE’s senior R&D engineer Neil Mullan, a lead designer on the Infinity range.

The R1500 also incorporates CDE’s patented Infinity screen technology, which eliminates welds from the high energy 1.2m x 3m screen box and results in a stronger and lighter screen that requires less power to provide the same acceleration as a traditional screen, reducing operational costs.

Source: CDE Global

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