Autoclaved Aerated Concrete Technology Plants and ... - HESS Group

Back-tilting and bed removalIn most tilt-cake systems the cake is autoclaved inthe vertical position. The HESS plants have combinedthe advandayes of the tilt-cake and flat-cakesystem.After the cutting is completed, the cake is tilted backby 90° onto a cooking frame. In the HESS systemno part of the mould or platform used for cuttinggoes into the autoclaves. After the cake has beentilted back into the horizontal orientation, the bottom/bedwaste will be removed before autoclaving.Autoclaving the cake while lying horizontally on thecooking frames allows efficient autoclave loadingand most importantly, will prevent most of the stickingof the layers, which is a typical disadvandayeof the traditional tilt-cake systems.HESS SYSTEMS PRODUCE NOPROCESS RELATED WASTE!Green separationOne of the HESS innovations is the green separator.Here the horizontal cuts (now lyingvertical) are carefully separated before autoclaving,leaving a small gap in between the layers.This innovation eliminates any sticking, whichis typical for other tilt-cake systems. Further thisgreen separation substantially improves the autoclavingprocess as steam can penetrate intothe cake more effectivety.Frame and bogey circulationThe green cakes on the cooking frame are stackedthree high onto autoclaving cars, referred toas bogeys. Autoclave buffer tracks in front of theautoclaves ensure that the cutting and packagingprocesses are less dependent on one another. Anautoclave traverser is used for loading and unloadingthe autoclaves, ensuring that this process isperformed in the shortest possible time, in order tooptimise autoclaving capacity.AutoclavingIn the autoclaves the cakes are cured for ca. 10 – 12hours at a temperature of 190° C with saturatedsteam at a pressure of 12 bar. The fully automaticautoclave control system ensures a safe and optimalautoclaving process, also allowing for steam transferand energy reutilization in combination with thecondensate system.10 11