In mill trials, Acrowood set up an 18-shaft screen with Trillium discs – three-sided discs manufactured with the DiamondRoll drive system. The triangular shape of the discs provided greater agitation.
A recent testing of our screen structure showed an overall efficiency of 93% green. The Trillium retained 75% of the large strands that topple and tumble over the surface of the screen that will form the surface of the board, while passing 25% of the undersized material through the screen’s 3 mm IFO. The DiamondRoll overs that were recovered strands but fines free were twenty percent of the original Trillium flow with five percent as the DiamondRoll under fines. These numbers can change based on what is preferred in the system.
The Trillium Screen uses the DiamondRoll drive design, a tried and true method. Key to the DiamondRoll and Trillium Screens’ adaptability is the drive system. Each drive group uses a continuous loop of chain, which drives each shaft. A single motor is located at the discharge end of each drive group. On one end of the shaft a special sprocket, known as a rack tooth sprocket, engages the chain as it is pulled across the top.
Because of the design of the teeth in the rack tooth rocket, the chain pulls the shaft smoothly, transmitting the power of the chain to the rolls. This drive system has proven to be efficient and strong, and an improved design over the “loop to loop” drive system.
Retaining More Desirable Strands
This photograph shows the <6 mesh, >14 mesh fraction generated by classification of the Trillium Accepts. The Gilson classifier upended these long slender strands and passed them through the 6 mesh screen. Using a 6 mesh fines definition, this material would be classified as “fines” and targeted for removal. Our impression is that this fraction is desirable and should be retained.
Maximum Application Flexibility
With great flexibility the Trillium and DiamondRoll Screening combination can be adjusted to fine tune the amount of material passed versus carried over the end of the screen. It provides high efficiency while maintaining the quality of the strands. With an evaluation of all the available technologies, Acrowood’s Trillium Screen is proven to be the best combination of performance and value.
Shafts are fabricated using a computer controlled robotic welder for precise disc positioning. The unique three-lobed disc shape provides excellent agitation for effective fines removal from either dry or green OSB strands.
Rack tooth sprockets fixed to the shafts using Trantorque™ bushings drive the shafts via sintered bushing chain. This simple, reliable drive system requires no periodic lubrication. Shaft bearings are sealed for life.
The triangular shape of the discs provides great agitation
The large strands that topple and tumble over the surface of the screen will form the surface of the board while the undersized material passes through the screen’s 3mm IFO to a DiamondRoll VIRO Fines
Screen below. This method allows fines to pass with the small strands while recovering good strands on the Diamond Roll.
Complete control of OSB strand separation characteristics
Variable frequency drive control of the individual drive groupings provides an operator control of the separation characteristics of the screen. Fines and the smallest strands fall through the first or early sections of the screen. These are directed to the inlet section of the DiamondRoll. Larger intermediate strands fall through the end of the Trillium, and are subsequently directed to the discharge end of the DiamondRoll.
Chain needs no lubrication
Oil lubrication has been eliminated from the side frame, since the chain is lubricated for life. The chain is a high strength sintered bushing roller chain, with lubricant incorporated into the structure of the bushing itself. The flange mounted bearings are grease lubricated. The fittings can be accessed directly, or can be piped to a central lubrication manifold. All components are built with long service life and minimal maintenance requirements in mind.
Dramatically increase your production efficiency
Limp, wet and fines rich green strands have always been a challenge to efficiently screen. The Acrowood Trillium Screen is the best solution to the problem. Fines are trapped between the strands in layers, complicating flow rate control with lumpy surges. Dry strands are stiff, fluffy and curved, often containing high fines. The flow rate from the drier is uneven, with heavy surges. Fines rob capacity in the drier. As much as 15 percent of fresh strands are fines.