Shotblasting machine from SR SCHINDLER type SR-1250

For the surface finishing of concrete products, an inline shotblasting plant type SR-1250 from the manufacturer SR SCHINDLER is installed on the dry side between the lowerator and the packaging line. Its processing section runs parallel to the dry side transport over a length of about 18 m. The SR-1250 shotblasting machine has a working width of 1,200 mm and processes layers of pavers with dimensions between 800 x 800 mm and 1,200 x 900 mm – layers with a side length of more than 1,200 mm are rotated by 90° and then transported further in the running direction with the narrower side. The maximum product thickness is 200 mm.

In the first step, a cuber Servo 900 takes a layer of pavers from the dry side transport and places it on a transfer table. A layer pusher transports the layer on the extended belt conveyor of the shotblasting machine in front of the infeed entrance lock. The shotblasting machine‘s rubber conveyor belt is ribbed across the direction of travel, which prevents the concrete products from drifting apart during processing. The layers are conveyed at a distance of approx. 600 mm from each other through the multi-layer rubber curtains of the infeed entrance lock into the shotblasting chamber. The chamber of the shotblastig machine in which the finishing process takes place is made of 12 % manganese hard steel to protect against damage and wear caused by the action of abrasive.

In the shotblasting chamber, two frequency-controlled turbines with 18.5 kW power each bombard the surfaces of the layer positioned below with steel or stainless steel beads. This exposes the fine aggregates used in the facing layer and gives the pavers the desired aesthetic surface effect. In addition, the surface is slightly roughened and slip resistance is improved. Once a layer has been completely shotblasted, it is transported further out of the shotblasting chamber. The abrasive supply to the turbines is automatically stopped and is only raised again as soon as the conveyor belt positions the next layer under the turbines.

In the following cleaning chamber, two high-pressure blowers with height-adjustable slot nozzles remove the last blasting abrasive residues from the surface of the processed concrete products. The contaminated abrasive is collected and cleaned of dirt particles in a cleaning system. It is then made available again in the blasting medium silo for the blasting process. The cycle time for the entire blasting process at Tobermore is between 13 and 15 seconds.

The processed stone layers are transferred by a second pusher to a conveyor belt to the pickup position. A second Hess cuber picks up the layers again and places them on empty production pallets on the dry side transport. The second cuber can also place already processed layers on a rearranging table, as required. A void layer is then formed on the table with gaps between the pavers, into which the fork of a forklift truck can reach during a possible later transport operation. After forming the void layer, the second cuber picks up the layer again and places it back on an empty production pallet on the dry side transport.

Trevor Smyth is very satisfied with the cooperation with the companies involved, including SR SCHINDLER and HESS GROUP. „There are always minor problems. But everyone involved has cooperated very well to get the plants up and running quickly and efficiently,“ says the Production Works Manager. The after-sales service of the companies involved can also be relied on, he says.

„The new block plant is now running extremely well and we are producing top quality products with it,“ says Smyth. With these high-quality concrete products, the company will continue to grow in Ireland, the United Kingdom and on the Isle of Man in the coming years, he adds.

For the full article, see

CPI Worldwide 2/21