User story: Towed screener compliments contractor’s crushing business

In addition to being used as a stand-alone machine, it has the potential to be placed under the discharge belt of his Herbst Agri Crusher, for direct feeding of crushed materials.

Each of the three conveyor belts are hydraulically folded to reduce the machine’s size for transport. Unfolding them reinstates tension for each belt, and readies the unit for work. Engaging the vibrating screen box provides the shaking function to sieve materials being loaded.

Its upper shaker deck removes over-sized materials, which are dropped onto a conveyor belt that stockpiles larger product at the rear of the machine. Smaller material cascades down over a lower sieve deck, producing two graded sizes that are unloaded by conveyor belts at either side of the machine.

“It looked a really useful bit of kit, that could handle different materials,” he recalls. “I had a local turf company looking for someone to screen 1,000 tonnes of top soil, and it also has the ability to screen compost to meet PAS100 quality standards.”

Towed by tractor, the Compac Screen has already received a few working modifications, to improve on-site set-up and durability. “The screen’s fixed front skids meant that it was tricky to set-up unless you were on a level site,” he says. “So we replaced them with Jost landing legs from a lorry trailer, so we could wind them up or down independently, to get the machine set correctly for optimum output.

“And using bolt-on legs, we can adjust their position through a series of holes, if we need a greater range of adjustment,” he adds. “We have also replaced the small road wheels with larger diameter items to help improve ground clearance when visiting farms, and this is a really useful feature for access.”

To load the screen, Mr Boundy says an eight-tonne midi excavator is the ideal solution. “Ideally, you position the excavator to load the screen from the front, but a short-radius excavator could sit anywhere, as long as it can reach the top deck,” he says. “Going forward, a wide intake box would be much more practical, and this could then be loaded using a telehandler and bucket.”

In terms of productivity, he says the screen is impressive, with a throughput of 100 to 150 tonnes/hour depending on the materials being screened. “It can soon make a good pile of material under the conveyor belts,” he says. “So you either move material from under the belts, or hitch a tractor on and pull the screen forward.”

When screening soil, he says best results come from dry material that crumbles and flows easily. “Aggregates are far more easily handled, but wetter materials can cause a build-up of fines that can eventually block the screen decks,” he says. “And occasionally, I need to switch off and reach in using a rake or hoe, to scrape the decks clean, to restore the separation quality.

“It is a very simple and robust machine, which works really well, though we have implemented a few changes to make it better for our own applications.”

He says that over-loading the feeder box can sometimes see material spill down through to the engine bay, having forced its way past a protective rubber flap. “I have added a piece of steel plate to close this area off and stop the overflow from happening,” he says. “And with hinges fitted, I can lower the plate and still access the sieve deck for cleaning.”

He has also added hinges to a bolted access panel on the right-hand side of the machine, to make it easier to grease the side conveyor belt’s lower rollers, and also to improve access for cleaning. He has also added an extended exhaust pipe, to prevent the machine from becoming covered in soot.

“It is a great machine, but we have found that farm life can be more demanding than working with builders, and we have simply made the Compac Screen better suited to our varied workload,” he says.

Typically, he reckons the screen will run for around two days on a tank of diesel, hinting at the Yanmar engine’s economical operation. “There is no fuel gauge, just a small sight tube, though it only shows the last quarter of fuel tank capacity, so it only warns you when you are about to run out. It would be more convenient if the sight gauge extended up near the top of the tank.”

For the Boundy family, the purchase of the mobile screen for on-farm recycling has yet to gather momentum.

“While the machine has not yet done a lot of work, it does offer a really useful means of improving the value of crushed materials,” he says.

“It is not an obvious choice for farmers, local builders or landscapers, but it should be. Compared to the cost of disposing of unwanted materials, we can crush and screen on-site, to provide a really useful recycled material at much lower cost than they can dispose of, and buy-in quarried aggregates.”