In 2006, the ceramics plant HISPAPLUS in Zamora (Spain) presented BERALMAR with a series of firing problems that were beginning to create a dire situation. The initial situation can be summarized by the following data:
- Daily production: 35 cars/406 tonnes.
- Impulse time: 15 minutes and 12 seconds.
- Waste: 8-10%.
The tunnel kiln, which had a double input and output door, a length of 130.5 m, an internal width of 4.5 m and a useful height of 2.2 m, was fuelled by natural gas. Moderate production levels had to be maintained to avoid higher levels of breakage, which, in spite of everything, were at a painful 10%. The firing curve revealed the origin of the problems: differences in temperature of up to 250 °C between high and low areas of the packages, in the pre-heating area and in the cooling area.