Demand grows as centrifugal screen proves its worth

31st March 2017 By: Robyn Wilkinson - Features Reporter

Market demand is growing for Johnson Screens’ all welded, one-piece wedge wire centrifugal screens after the completion of a three-year trial at sugar producer Illovo Sugar subsidiary Ubombo Sugar’s mill, in Swaziland, which started in 2014, says filtration specialist Filteg Solutions.

Johnson Screens is a stainless steel screen brand from engineering products and services provider Aqseptence Group that offers an innovation in sugar processing technology by significantly enhancing the performance of continuous centrifugals and reducing operating costs.

The screens are offered exclusively by Filteg Solutions in South Africa and, while the market was initially sceptical of the new product when it was first introduced in 2012, Filteg Solutions sales representative John Turner says the highly successful results of the trial at Ubombo have proven its worth and it is subsequently gaining popularity in the local sugar processing industry.

“The centrifugal screen can improve sugar purity levels and increase overall profits. In this trial, the cost of the screens was recovered within two years based on labour savings from not having to change the screens. The final molasses purity at the mill was improved by 0.34 units, resulting in increased sucrose recovery. We highly recommend that other mills install this product and see the benefits for themselves.”

Turner explains that the screens use Vee-Wire technology, enabling them to offer significant benefits over the conventional foil screens used for separating sugar and molasses when processing sugar.

The technology has increased mechanical strength, making it extremely durable and endowing it with a high resistance to abrasion, corrosion and damage from impact by foreign objects, he highlights. The self-supporting structure of the basket is, moreover, specifically designed and engineered to withstand high stresses and load conditions of the industry.

“This gives a longer screen life that can be measured in seasons, not weeks, as is the case with conventional foil screens. This equates to less downtime and lower maintenance costs for sugar mills.”

In addition, he points out that the screen has a precise slot opening and a larger percentage of open area, thereby increasing the amount of sugar recovery. A slot width of 40 µm, for example, has a similar open area to a foil screen with a slot width of 60 µm, reducing sugar losses.

The screens have variable slot openings from 20 µm upwards and Turner highlights that independent trials have shown that the screen permits better separation of molasses from the raw sugar, resulting in maximum purity of the sugar crystals. Improved separation characteristics also allow for the use of smaller slots, which also reduce sugar loss.

“Johnson Screens centrifugal screens are also supplied in one piece, with no fitting of multiple segments required.”