When discussing screening efficiency, people often say, “Well, I can ‘always’ get more capacity from an inclined screen.”
Ed Sauser, product manager for Superior Industries, says he hears that all the time. So, is it true? Do inclined screens “always” outperform horizontal screens? Myth or reality? Sauser weighs in on the topic.
When choosing screens, Sauser notes that producers are most concerned about throughput, product gradations, and fines removal - and some may assume that since inclined screens operate at a steeper angle (15- to 20-degrees), gravity alone will lead to more throughput. But that’s not always the case, especially when the inclined screen is overloaded – a common situation that leads to material carryover, recirculating loads, and costly out-of-spec product.
“When selecting and sizing a screen, we’re focusing on what we can get through the deck openings, not over or across them,” says Sauser, explaining that “more capacity” on an inclined screen is often just “more conveying” – as more material often skips across the surface – not through the deck openings.”
Plant operators often equate the faster material travel rate on the inclined screen with higher production. In truth – the horizontal screen will always outperform an overloaded inclined screen when measuring sellable tons per hour. Horizontal screens appear slower yet consider that the more time that material remains on the deck, the more opportunities for proper material stratification. Without the latter, producers face higher costs per ton due to increased wear and material reprocessing.
Sauser stresses that each screen type has its advantages and each has its place in the industry. He notes that one of the most popular screens on the market is the elliptical-stroke horizontal screen, a high-energy machine with twice the horsepower and G-force of typical units. Sauser explains that horizontal screens accommodate heavier bed depths while using an oval throw to move material on the deck, allowing these units to perform exceptionally well in wet, sticky, high-moisture applications, or those where “precision stratification” produces tight, exacting product specifications.
Alternatively, inclined screens require less energy while making use of gravity. Typically demanding a smaller capital investment, inclined screens are ideally suited to higher-volume applications, with less stringent specifications.
The common perception that inclined screens always outperform horizontal screens is a myth. Each screen type has its strengths and the choice of either depends upon the specific application, material parameters, and production goals.
The key takeaway on screen types? Inclined screens are great for speed and volume in general applications. Horizontal screens are best for precision stratification, fines recovery, and overall efficiency.
Always consult with your manufacturer’s product managers and applications engineers to ensure the best screen selection for your application. And remember – more tons across the screen deck does not always equal more high-quality, in-spec product.