Kiln

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A kiln is generally in the traditional meaning of the word, a temporarily erected oven without its own supporting structure. The fuel (wood or coal) and, if necessary, other raw materials are alternately piled up in a self-supporting construction and finally carefully sealed (e.g. with clay ). The ignition of the fuel starts at high temperatures with more or less extensive exclusion of oxygen, the chemical transformation process of the enclosed raw material into higher-quality substances (see pyrolysis ).

Meileröfen used to be u. a. used for the production of:

A bio-pile or compost pile is not ignited, with it the rotting heat of decomposable materials is used (see also compost ).

Even roasting ovens for roasting iron ore were temporarily erected in Meiler form.

Since piles can be set up quickly in the immediate vicinity of the extraction point for the raw material to be processed (e.g. wood, clay or iron ore), there are no long transport routes, which was a decisive advantage in pre-industrial and early industrial times. With the increasing efficiency of the transport industry , piles were increasingly replaced by more efficient stationary furnaces.

In industrially less developed countries, piles are still used today, e.g. B. for brick production .

Atomic pile

Containment dome of a nuclear reactor

The colloquial term atom meiler for a nuclear reactor has different backgrounds. The first research nuclear reactors, such as the Chicago Pile of the team around Enrico Fermi , were constructed in a similar way to coal piles , in that the nuclear “fuel” uranium was alternately piled up with graphite as a moderator and then finally with it radiation-insulating panels was covered. However, this lead cover had exactly the opposite purpose as the traditional kiln, namely to protect the environment and not the fuel.

There is another analogy to the coal pile, especially with breeder reactors : Both are used to obtain new, more effective fuel - in one case coal is obtained from wood, in the other case plutonium is obtained from uranium .

Functionally, today's nuclear reactors no longer have anything in common with kilns. The term "pile" is therefore now only with the form of large, highly visible concrete containment connected reactors of older design that resembles the typical vaulted form of carbon kiln.

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