Water trough barrier

A water trough barrier in a viewing section in the Ibbenbüren mining museum

A water trough barrier is made of water-filled troughs explosion barrier for the mining underground . Water trough barriers are independent protective systems. They serve to contain the extent of a firedamp explosion or a coal dust explosion . Water trough barriers are regularly checked for their fill level.

Basics and history

In an explosion, the pressure wave always precedes the explosion flames. As a result, a chain reaction can occur if the transmission of the explosion is not interrupted by the first explosion. The first water trough barriers, made of wooden boxes filled with water, were used successfully in Austrian mining as early as the middle of the 20th century. In the second half of the 20th century, the effectiveness of water trough barriers was tested in a large number of underground tests. Explosion tests were carried out in several mines and test pits. Different types of locks were examined for their effectiveness.

construction

Certain regulations apply to the construction of water trough barriers; these are regulated in the European standard EN 14591-2-2007. The barriers are usually installed in the roof at a height of over 2.6 meters. There are five different types of water trough barriers. The barrier consists of a support frame or a support beam in which the water troughs, depending on the type of barrier, are either suspended, set up or partially suspended and partially set up. The entire construction, supporting frame / supporting beams and troughs, is called a supporting platform. The water troughs are made of a special plastic, they are open at the top and have a capacity of 80 liters. Each trough is equipped with a lid to cover it. Each trough is filled with 80 liters of water after assembly. Since the water in the troughs evaporates after a certain time , the troughs have to be refilled regularly. To reduce the loss through evaporation, a solution of water and calcium chloride is used instead of pure water . So that the troughs can be emptied without destroying them, each trough has an outlet opening at the bottom that is closed by a closure piece.

The water trough barrier must be constructed in such a way that there is 200 liters of water per square meter of the cross section of the route throughout the barrier. In addition, a barrier must have a length of at least 20 meters. The miner describes barriers constructed in this way as "concentrated barriers". But there are also divided barriers that are not concentrated in one place, but are distributed throughout the mine . The troughs that are within three meters of a divided barrier are called a trough group. The distance between the individual trough platforms can be up to 30 meters with a divided barrier. In the case of divided barriers, the amount of water in each trough platform depends on the cross-section of the route and the distance between two trough platforms. For example, there must be at least one liter of water in the respective barrier for every cubic meter of volume of the route section . In addition to the normal locks, there is also the water trough quick lock. Such barriers are used for damming work where there is a risk of explosion. They serve to protect the employed with the Abdämmarbeiten miners , to protect them against any possible explosions. Water trough quick locks consist of at least six water trough platforms, one above the other. The water trough platforms are attached to the track extension . A water trough quick barrier must contain at least 60 liters of water per square meter of cross section. The water troughs used must be filled with at least 40 liters of water.

function

The barrier is constructed in such a way that the troughs filled with water are destroyed by the pressure wave hurrying ahead. The pressure wave first lifts the trough lid and destroys the roof. The water in the troughs is now thrown out. Then the water trough breaks into several parts and the water spreads upwards. In the end, the water trough bursts apart completely and the water still in it splashes out. The water is now evenly distributed over the entire cross-section of the route . The resulting wall of water cools the flames and at the same time extinguishes them. As a result, the transmission of the explosion is now interrupted and another explosion in the form of a coal dust explosion can no longer take place.

Individual evidence

^ ^A ^b ^c ^d Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia. 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Explosion protection in underground mines - Protection systems - Part 2: Passive water trough barriers. European standard EN 14591-2, European Committee for Standardization, Brussels 2007, pp. 1–6.
^ ^A ^b ^c ^d Heinrich Otto Buja: Engineering Handbook Mining Technology, Deposits and Extraction Technology. 1st edition, Beuth Verlag GmbH Berlin-Vienna-Zurich, Berlin 2013, ISBN 978-3-410-22618-5 .
↑ ^a ^b ^c Matthias Düngelhoff: Just don't stir up dust . In: Berufsgenossenschaft raw materials and chemical industry. (Ed.): BG GRCI.magazin. No. 1/2, Druck Neues Druckereigesellschaft mbH & Co. KG. (Kempen), Bochum January 2010, pp. 18-19
^ Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1962.
↑ European Coal and Steel Community - High Authority Commission (Ed.): Eighth report of the standing committee for operational safety and health protection in the coal industry . 1970, p. 18
↑ Steffenhagen, Meerbusch: Explosion tests with barriers and dams II . In: Commission of the European Communities (Ed.): Research books coal. No. 30, Luxemburg 1970, pp. 9-33.
↑ ^a ^b Ernst-Norbert Risse: Water trough for explosion barriers in underground mining operations . Patent specification of L. Risse GmbH, Castrop-Rauxel 1996, date of patent issue July 24, 1997, documentation number DE 19614735C1 July 24, 1997.
↑ ^a ^b ^c ^d ^e ^f ^g Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 .

Web links

Commons : Water trough lock - collection of pictures, videos and audio files

Remarks

↑ The volume of route sections is calculated from the product of the mean route cross-section and the associated length. (Source: Explosion protection in underground mines - Protection systems - Part 2: Passive water trough barriers. European Standard EN 14591-2 )

[Quelle_1-1] A ^b ^c ^d Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia. 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .

[Quelle_3-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Explosion protection in underground mines - Protection systems - Part 2: Passive water trough barriers. European standard EN 14591-2, European Committee for Standardization, Brussels 2007, pp. 1–6.

[Quelle_2-3] A ^b ^c ^d Heinrich Otto Buja: Engineering Handbook Mining Technology, Deposits and Extraction Technology. 1st edition, Beuth Verlag GmbH Berlin-Vienna-Zurich, Berlin 2013, ISBN 978-3-410-22618-5 .

[Quelle_5-4] Matthias Düngelhoff: Just don't stir up dust . In: Berufsgenossenschaft raw materials and chemical industry. (Ed.): BG GRCI.magazin. No. 1/2, Druck Neues Druckereigesellschaft mbH & Co. KG. (Kempen), Bochum January 2010, pp. 18-19

[Quelle_4-5] Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1962.

[Quelle_6-6] European Coal and Steel Community - High Authority Commission (Ed.): Eighth report of the standing committee for operational safety and health protection in the coal industry . 1970, p. 18

[Quelle_7-7] Steffenhagen, Meerbusch: Explosion tests with barriers and dams II . In: Commission of the European Communities (Ed.): Research books coal. No. 30, Luxemburg 1970, pp. 9-33.

[Quelle_9-8] Ernst-Norbert Risse: Water trough for explosion barriers in underground mining operations . Patent specification of L. Risse GmbH, Castrop-Rauxel 1996, date of patent issue July 24, 1997, documentation number DE 19614735C1 July 24, 1997.

[Quelle_8-9] ↑ ^a ^b ^c ^d ^e ^f ^g Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 .

[Anm._EN_14591.-10] The volume of route sections is calculated from the product of the mean route cross-section and the associated length. (Source: Explosion protection in underground mines - Protection systems - Part 2: Passive water trough barriers. European Standard EN 14591-2 )