The annealing of cellular glass is always the hardest issue during a start up by less experienced people. Indeed, annealing easily takes about 15 hours. This is the minimum time we have to take after every change. In case the production is wasted due to annealing problems, 15 hours is a very long time to wait.The hard thing about adjusting the annealing is that the lehr is a black box, without any possibility to observe something.
However, with software calculating the stress during and after annealing, the operator can predict breakage during or after annealing when he changes thickness, temperature curve, density, speed, etc. Production losses due to annealing problems will be largely reduced. Annealing is considered to be satisfying when there is no breakage during production, in the ware house or due to one-side contact with hot bitumen at maximum use temperature (220°C). The last situation is typical for cellular glass, installed on a flat roof, the main application of cellular glass.
BELGLAS let develop software to calculate the stress during annealing and after annealing for a chosen temperature curve, thickness, etc… . The program uses the stress and structural relaxation theory of Gilard & De Bast together with the well known thermal properties of cellular glass.
The program is written in GNU FORTRAN and runs under UBUNTU LINUX. It reads a file with the properties of the ribbon / block and a file with the temperature curve. After calculation, a file is written with on every line: time / surface temperature / inner temperature / surface stress / inner stress. This file can be loaded in a spreadsheet program from LibreOffice or visualized with GNU PLOT, like shown here under.
BELGLAS delivers the program on a laptop running under UBUNTU. Open source software can be installed on request. A internal terminal emulator is used to run the program. Training can be foreseen on demand at BELGLAS or with VOIP.