Alwin Nienaber, technical director at Weba Chute Systems, says that in addition to overcoming the challenges of material degradation and excessive dust, these new chutes will be designed to address material segregation, screen presentation and screen efficiency.
Challenges in this particular application at the steel plant include presentation of material as well as that one of the screens has been experiencing a greater volume of fines than the other. The segregation of material being presented to the one screen was not only responsible for the inefficiency of the screen but also for causing extremely high wear to the screen panels.
“Presentation of material onto the screen has been addressed through the custom engineering of the screen feed chute, and this design allows the absolute control of the discharge velocity of the material. By doing this, the Weba Chute System will be able to present the material in an even spread at the feed end of the screen,” Nienaber explains. “This will ensure the efficiency of the screen and eliminate the dead zones on the screen deck.”
The Weba Chute Systems engineered solution is a bifurcated chute which feeds the two separate conveyors as well as the two sizing screens. Nienaber says that the original installation had not been able to evenly split the flow of material into two equal streams and this resulted in the one screen seeing up to 75% more fines than the other.
“Using applications knowledge and experience built up over years, our team was able to engineer a solution with a completely different splitting orientation,” he says.
With more than 4 500 Weba Chute Systems operating successfully across a wide range of commodities, the company has a long established track record of leveraging its engineering expertise to custom design transfer points to meet exacting individual applications.
Nienaber is quick to add that few transfer points are engineered using such an in-depth level of input, and that this is why the Weba Chute System has gained such a solid reputation internationally.
“It is more about addressing the transfer process itself and not just fabricating a chute that will move material from point A to point B. This is why it is essential that our engineers do a comprehensive plant assessment to obtain a full understanding of the actual conditions and challenges that are faced by our customer,” Nienaber says.
“This access to accurate and reliable information on the processes within the plant certainly assists our team, and in the case of this order our experience played a major role in engineering a solution where the orientation of the split was changed.”
The changes to the orientation have necessitated substantial structural and civil modifications to incorporate the custom engineered transfer points and acceptance that this would provide a real solution demonstrates the confidence that the customer has in Weba Chute Systems.
“This is a good example where an engineered transfer point can lower the total operational costs on a plant, and the entire process was facilitated by the customer’s long term view,” Nienaber says.
Weba Chute Systems are specifically engineered to control the direction, flow and velocity of material being transferred, and through this these transfer chutes and systems are able to achieve equipment plant availability as high as 90 to 95%.
Following the design of the Weba Chute Systems, simulations were done using Discrete Element Modelling (DEM) as a verification tool and this provided the assurance to the customer that the engineering design is accurate and will achieve the desired outcome.
All three Weba Chute Systems chutes are in final design and expected installation will be in 2017.