Initial experiences with a new sugar silo discharge system

In 1995 and 1996, the Dinteloord and Euskirchen sugar factories built two sugar silos with effective capacities of 60,000 tonnes and 50,000 tonnes to the design of the Comet firm. Both silos have a double-wall steel shell, heated by warm air, and a ventilation system integrated in the floor for conditioned air. A special feature of the silos is the design of the roof, the membrane of which rises when the pressure exceeds 0.2 bar. The principal innovation in these silos is the discharge system which allows simultaneous delivery and withdrawal. The most important component is a rotating scraper arm which makes it possible to empty the silo almost completely without using labour. The first 70% of silo contents are discharged conventionally by gravity into a central cavity. In this phase, the sole function of the scrolls installed in the central cavity is to control the rate of withdrawal. When a natural pile has been formed and the central cavity is no longer full of sugar, the rotating scraper arm starts to operate. The scraper arm, mounted in the middle of the central cavity, descends onto the pile and scrapes sugar into the central cavity at 20 revolutions per hour. The scraper arm is controlled in accordance with the fill level by sensors installed in the central cavity.