Field fire brick

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Field fire brick from 1847
Dirmsteiner brickworks

A field fire brick factory , in southern Germany also Ziegelhuette or Ziegelstadel , was called a pre-industrial operation for production of bricks , as was common until about the mid-19th century addition. The field fire ovens existed until the field being dismantled was bricked out. This situation explains the inadequate database on this type of brick .

Procedure

The brickworks was a seasonal part-time business. It consisted of pits that supplied the raw material. There were also barn-like buildings that sometimes consisted only of roofs supported on beams and the shaft furnace . This consisted of only four walls, which were provided with poking holes. Wood , peat or coal were used as fuel . The combustion process itself had some shortcomings. Sometimes only a third of the fired stones could be used. A third was always unusable due to ash, slag or melt (overheating). The remaining stones were not always perfect either. The temperature within the furnace was inconsistent, so that uneven fires leading to defects were common. Even strong winds could cause an uneven fire. The fuel consumption was enormous. It was around 500 kg of coal per 1000 stones and was thus 3 to 4 times higher than in the later ring kiln .

Raw material preparation

The clay was dug up with hoes and spades in the autumn. Wheelbarrows were used to transport clay from the pits. The material was laid out in thin layers for weathering (Mauken). The clay had to lie there for at least six months, clays containing slate even for several years. A weathered area of ​​half a hectare was required for a million stones. After weathering, the material came into lined pits (swamps), where it was mixed with water and admixtures of stones and roots were removed. The material was pounded by humans or animals for homogenization. The wet clay was painted by hand in rectangular mold frames on painting tables. The shaped stones were left to dry for 12 to 14 days, or longer, under protective roofs or outdoors. After drying, they were put in the oven.

fire

It took about three days to insert around 30,000 stones that a normal shaft furnace could hold. To build a chimney with a height of 45 m, around 50,000 stones were required. The brick blanks, piled up to a height of 3.5 m, had the shape of a cuboid that tapered towards the top. They were wrapped in a jacket made of damaged blanks and piled up with spaces in between for the fuel. Then the whole thing was covered with straw-strewn clay and smeared. It took about nine days to fire, about five days to cool the furnace and two to three days to remove the stones. That was a total of just under three weeks.

See also

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