Osborn launches new portable asphalt plants

July 2007

Johannesburg-based bulk materials handling and minerals processing specialist Osborn has launched a new, low cost plant for the production of hot mix asphalt.

This addition to Osborn’s product range is being offered through United States-based sister company CEI Enterprises, also part of the Astec Industries group of companies. Osborn will officially distribute the CEI NOMADtm hot mix asphalt plant throughout southern Africa, the company has announced.

“The NOMADtm meets the needs of contractors on small projects such as driveways and parking lots, as well as those working on secondary roads, especially in rural areas,” comments product manager Ron Hannon. “It can also be used effectively on projects to widen or repair existing freeways.

“Basically, this highly portable plant is suited to all applications where the contractor wants to eliminate the need to transport asphalt. It has enormous potential for use in southern Africa’s rural areas, and we will be actively marketing it to contractors working in these areas, as well as to local government.

“Its employment on rural road building contracts can save time, money, and ensure a better quality road,” Hannon asserts.

To date Osborn has sold two of these plants - both to Much Asphalt. A third unit, sold directly by US-based CEI Enterprises to civil contractor AG Thomas, is operating in Swaziland.

The NOMADtm produces up to 130 tons of hot mix asphalt an hour. It consists of four components: a portable tank that heats and stores liquid asphalt; a portable drum mix unit that dries aggregate and mixes it with liquid asphalt cement; the drag conveyor and hopper unit that transports the mix to an elevated hopper so it can be loaded into trucks; and a portable control house.

The NOMADtm is trailer-mounted and can easily be moved from one job site to another. The hopper unit is easily transported by a conventional flat-bed trailer. “Upon arrival at a new site, the plant can be rapidly set up for operation within just a few hours,” Hannon notes.

Cranes are not required for setup. A front-end loader is all that is needed to assemble the plant’s components, which are then connected by special cables.

Outlining the NOMADtm plant’s operating process, Hannon says that the portable drum mix unit first dries aggregate and coats it with asphalt cement to produce hot mix asphalt. “Its major parts are a drum, burner, exhaust fan, aggregate bins, aggregate feed system and dust collection system. All are mounted on a single trailer frame. A tractor with a fifth wheel attachment can transport the unit.

“The drum functions as a combination dryer and mixer.”

The plant’s portable tank unit heats and stores liquid asphalt cement. It also provides hot oil to heat other components of the plant. Its major parts are an unloading pump, asphalt tank, burner and fire tube, metering pump and hot oil system. All are mounted on a trailer. As with the drum mix unit, a tractor with a fifth wheel attachment can transport the unit.

The NOMADtm’s drag conveyor is driven by an electric motor. It receives hot mix from the discharge chute of the drum unit and conveys it to the hopper. The hopper functions as a surge bin. It has an air-cylinder that opens the gate to dump the hot mix into the bed of a truck. The drag conveyor and elevated hopper are constructed as a single unit. A detachable stand supports the hopper and drag conveyor in an upright position.

The stand has a caged ladder and platform. The pieces can be transported on a single flat bed trailer that is not included with the plant.

Hannon points out that the drag conveyor and hopper offer significant worker safety advantages compared to the skip hoists often used in Africa, and they are relatively simple to maintain. In addition, because the drag conveyor is enclosed, the hot mix asphalt is subject to less oxidation than when a skip hoist is used, and less blue smoke escapes. The hopper is designed to minimize segregation of the mix when it is discharged into the truck.

He stresses that the NOMADtm’s drag conveyor is built to last considerably longer than competitive units. “Moreover, it is designed so that parts are easy to replace.”

Comparing its features with many other units on the market, Hannon notes that the bottom liner is manufactured from ½-inch chromium carbide steel wear plate, which lasts six times longer than AR plate.

“Its side liners are ½-inch AR-360 wear plate. The flame-hardened head sprocket is segmented, so it can be replaced without removing the drag chain. The unit features a high-alloy head shaft and hardened four-inch, heavy-duty roller chain. In addition, the conveyor discharge opening is set back from the head sprocket, so that the mix is fully discharged from each flight. This eliminates carry over of residues that cause excess wear of the head sprocket and chain.

“The idlers that support the chain as it returns are also extra wide, to minimize noise and vibration and to increase the life of the chain and liner.”

The fourth element of the NOMADtm plant, the portable control house, is also a high quality unit, Hannon states. “The control house is mounted on a trailer and can be transported by a pick-up truck with a trailer hitch. It features air-conditioning, heating and interior lights. Installed in a steel console, the controls include three temperature controllers, a burner management controller, a programmable process controller and three MBUs.

“The NOMADtm includes exceptional features that you would expect to find on more expensive units, and we are very excited to be adding this plant to Osborn’s product offering,” Hannon concludes.

/Ends

Based in Elandsfontein, Johannesburg, Osborn Engineered Products SA (Pty) Limited (trading as Osborn) is a leading manufacturer of bulk materials handling equipment and specialist turnkey materials handling contractor for mobile and fixed crushing and screening plants and conveyor systems.

Osborn is a member of the Astec Industries Inc. group of companies, a leading American manufacturer of plant and equipment for aggregate processing, asphalt road building and pipeline and utility trenching.