Oxygen lance
An oxygen lance (also known as a thermal lance ) is the main component of a technical process in which gaseous oxygen flows at high pressure through a metal tube, which at the end of the tube reacts with the tube in a burning process, with very high temperatures occurring depending on the metal fuel. Technical constructions with an oxygen lance are used for various purposes.
The combustion process with oxygen was invented in the 1900s by Ernst Menne . In Kreuztal ( Siegerland ), in the course of a demonstration of the efficiency of his device, he opened a tap hole in the blast furnace in seconds by means of a 1/2 " inch (≈ 1.27 cm ) gas pipe connected to an oxygen bottle , which several smelters had previously tried unsuccessfully to poke a hole.
Cutting burn
In addition to the process, the term often directly refers to this type of cutting torch , i.e. one of the technical devices in which the process of the oxygen lance , also known as the oxygen core lance, is used. The term thermal lance is also used here .
The burner construction of an oxygen lance consists of a long hollow rod, which is filled with steel wires to increase the surface area and through which gaseous oxygen flows at high pressure and speed. After heating and igniting the flame at the pipe outlet, the pipe material begins to burn under the oxygen with a strongly exothermic reaction at temperatures of up to 5,530 ° C. The commercially available standard version of this special combustion pipe has a diameter of 3/8 inch and a length of three meters, with or without a thread and socket. Common variations are available with lengths of 1.5 to 6 meters and diameters of 1/4 and 1/2 inches.
The resulting fire lance is placed on the material to be cut or pierced and is constantly tracked. The temperatures are sufficient to melt even substances with a very high melting point . The oxygen lance is used to cut through steel, concrete (gravel, sand and cement ), reinforced concrete and brickwork. Oxygen lances are used in disaster control, but also in iron and steel works (sampling, piercing blast furnace). The extremely hot combustion of the iron wires and the iron pipe in the oxygen flow as well as the flow pressure of the flame and combustion gas creates a cutting torch effect, molten material and combustion gases are removed from the combustion point by the gas flow. Since the pipe on the flame cutting device is consumed by use, it must be replaced periodically if it becomes too short.
Oxygen lances can also be used under water without too much modification; this is only the burning steel pipe z. B. wrapped with insulating tape to prevent excessive cooling, which could lead to a breakdown of the combustion.
Oxygen lances were occasionally used for break-ins .
Steelmaking
A similar structure for refining the steel can be found in steel production using the LD process . In this process, oxygen is blown onto the liquid melt, and pig iron is converted into steel through decarburization (burning of the excess carbon) .
Individual evidence
- ^ Otto Johannsen (on behalf of the Association of German Ironworkers): History of Iron . 3. Edition. Verlag Stahleisen mbH, Düsseldorf 1953, p. 439 .
- ↑ Cases were dealt with in the program Aktenzeichen XY ... unsolved on March 8, 1974.
