Weather stove

Weather furnace with above-ground firing

A weather furnace used to be a construction in mining that accelerated the pull of the weather through a fire. For this purpose, coal or wood was burned in the weather shaft. The resulting hot gases have increased buoyancy . This increases the convection in the weather shaft. Weather from mining is transported faster up to the surface of the earth. Weather ovens were used on some mines in the Harz mountain area up to 1901.

Functional principle and structure

The principle that heated air expands and thus becomes thinner and lighter is used in the weather stove. This lighter air rises and creates a suction. This suction causes a higher weather speed in the mine workings . The first weather stove was invented by Johann Bartels in the 18th century. The stove had a particularly large grate surface and was walled into a vault. The entire air supply for the furnace took place via the weather coming from the mine. In the course of time there have been different construction principles, with either above or below ground firing. The firemen operated the weather ovens . The firemen were miners who were particularly familiar with operating the weather furnaces.

Use of the boiler house chimneys

When a mine is in operation, it is also possible to use the boiler house chimneys for weathering. To do this, it is necessary to clad a section of the shaft in a weatherproof manner. This run is connected to the chimney of the steam boiler via a canal. The air is heated by the exhaust gases from the boiler and creates a buoyancy for the downweather. Especially in pits that are easy to ventilate and in which other facilities for artificial ventilation are missing, this method is an alternative to the separately fired weather oven. At the Kaiserstuhl colliery in Dortmund, the 80 meter high chimney of the boiler house was used for ventilation. With this method, 11.310 cubic meters of waste air could be extracted per second.

Installation above ground

When the weather furnace was installed above ground, the furnace was installed several meters to the side of the weather shaft in a brick chamber. Starting from the shaft, a weather channel was created until shortly before the location of the weather furnace. At the end of the weather channel, a high chimney was built over the weather channel. For large amounts of weather , the chimney must be large in diameter and have a sufficient height. If the stove is now being fired, the air in the chimney is heated. The heated air rises and creates a negative pressure. This negative pressure sucks the weather out of the mine building via the weather channel. Part of the weather is used as combustion air for the weather stove. However, there must be enough oxygen in the weather for this type of firing. The weather stove burns very badly in dull weather . If there was bad weather in the pit, these ovens could not be used. Here weather ovens had to be used in which the exhaust gases were vented to the environment via separate pipes. The pipes were installed in such a way that they were washed out by the weather. The exhaust gases heated the pipes and these in turn warmed the pit weather, which was thus weathered. However, above-ground weather ovens were used less often than underground ovens. The reason for this was the lower performance of these ovens. The output of these ovens was on average 100 m ^{3 of} air per minute. To weather an amount of 160 m ^{3 of} air, the heating energy of around one kilogram of hard coal was required. This was mainly due to the relatively low height of the chimney. The height of these chimneys was between 35 and 50 meters. Because of this relatively low height, the heated column of air was only very low. The air in the shaft was not heated with this technology and therefore did not generate any lift.

Underground installation

With underground installation there are two options for setting up the weather oven, either directly under the shaft or to the side of the shaft. The installation directly under the shaft or the extending run is only carried out for small systems. In the case of larger systems, the weather furnace is placed sideways from the shaft. For this purpose, the ovens are installed between 18 and 45 meters to the side of the shaft. The furnace exhaust is connected to the weather shaft via a moderately rising channel. When used in coal mines in the preparation of the oven must be particularly vigilant to ensure that no fire can occur, especially if in the immediate vicinity of the footwall coal seams are present. To prevent fire, the sole area of the ash trap must be provided with a layer of clay and a roller layer of bricks.

Either a partial flow of the waste weather or a partial flow of the fresh weather is fed to the furnace as combustion air. When the waste stream is used as combustion air, the waste stream is often refreshed by fresh weather. In mines at risk of firedamp , the combustion air must always come from fresh weather electricity. The fresh weather is supplied via a separate duct or duct . In this case, the weather is also conducted via a separate channel and directed into the shaft above the weather furnace. The high air column in the shaft is heated by the exhaust gases from the weather furnace flowing into the shaft and rises to the top. The heating of the air column is economical if the heating does not exceed 45 ° Celsius. By heating the air column to 50 to 60 ° Celsius, up to 40% more fuel is required, but only a ten percent increase in the amount of weather is achieved. On average, the weather was heated to 34 ° Celsius, in some cases up to 70 ° Celsius. A weather furnace installed underground was used to weather between 280 and 1380 m ^{3 of} air per minute. In the underground weather furnaces, the heating energy of around one kilogram of hard coal was sufficient to weather 740 m ^{3 of} air.

The underground weather ovens work more economically than ovens, but they also involve some dangers. Improper handling of the stove can lead to a pit fire . This risk is particularly high in coal mines. A protective masonry jacket around the stove prevents excessive heating of the surrounding mountains . However, the chimney becomes impassable due to the rising exhaust gases . Another danger is that, in the event of a fire in the shaft or at another point in the mine, the direction of the weather changes and the exhaust gases from the weather furnace get into the mine workings.

Individual evidence

^ Moritz Ferdinand Gätzschmann: Collection of mining expressions. 2nd edition, Verlag von Craz & Gerlach, Freiberg 1881
↑ ^a ^b The history of mine ventilation (accessed on June 5, 2012)
^ Heinrich Veith: German mountain dictionary with evidence. , Published by Wilhelm Gottlieb Korn, Breslau 1871.
↑ ^a ^b Carl Hartmann: Concise dictionary of the mountain, hut and Saltwork science of mineralogy and geognosy. Third volume, 2nd edition, Bernhard Friedrich Voigt bookstore, Weimar 1860.
^ Wilhelm Leo: Textbook of mining science. , Printed and published by G. Basse, Quedlinburg 1861.
↑ ^a ^b ^c ^d ^e ^f ^g ^h Gustav Köhler: Textbook of mining science. , Second improved edition, published by Wilhelm Engelmann, Leipzig 1887.
^ ^A ^b Albert Serlo: Guide to mining science. Second volume, 3rd edition, published by Julius Springer, Berlin 1878.
↑ ^a ^b ^c ^d ^e ^f ^g ^h Fritz Heise, Fritz Herbst: Textbook of mining studies with a special focus on hard coal mining. , First volume, published by Julius Springer, Berlin 1908.
^ ^A ^b ^c Emil Stöhr: Catechism of Mining Studies. , Lehmann & Wentzel bookstore for technology and art, Vienna 1875.

Web links

Digitization of the Polytechnic Journal, content on the keyword Wetterofen , DFG - German Research Foundation

[Quelle_9-1] Moritz Ferdinand Gätzschmann: Collection of mining expressions. 2nd edition, Verlag von Craz & Gerlach, Freiberg 1881

[Quelle_0-2] The history of mine ventilation (accessed on June 5, 2012)

[Quelle_8-3] Heinrich Veith: German mountain dictionary with evidence. , Published by Wilhelm Gottlieb Korn, Breslau 1871.

[Quelle_B-4] Carl Hartmann: Concise dictionary of the mountain, hut and Saltwork science of mineralogy and geognosy. Third volume, 2nd edition, Bernhard Friedrich Voigt bookstore, Weimar 1860.

[Quelle_7-5] Wilhelm Leo: Textbook of mining science. , Printed and published by G. Basse, Quedlinburg 1861.

[Quelle_2-6] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Gustav Köhler: Textbook of mining science. , Second improved edition, published by Wilhelm Engelmann, Leipzig 1887.

[Quelle_3-7] A ^b Albert Serlo: Guide to mining science. Second volume, 3rd edition, published by Julius Springer, Berlin 1878.

[Quelle_1-8] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Fritz Heise, Fritz Herbst: Textbook of mining studies with a special focus on hard coal mining. , First volume, published by Julius Springer, Berlin 1908.

[Quelle_5-9] A ^b ^c Emil Stöhr: Catechism of Mining Studies. , Lehmann & Wentzel bookstore for technology and art, Vienna 1875.