Miner pipe
The miner's pipe is a pipe for electrical installation that is no longer used today and into which individual insulated wires have been drawn. It was named after its manufacturer, Bergmann Elektrizitätswerke AG in Berlin, founded by Sigmund Bergmann .
Originally the pipe consisted of a waterproof ( bitumen-soaked ) paper pulp without a protective coating. From around 1900, it was given a folded jacket made of sheet brass , leaded sheet steel or sheet steel with an aluminum layer to better protect the paper pulp .
Miner pipes were made in 3 m long bars with an inner diameter of 9, 11, 13½, 16, 21, 23, 29, 36 and 48 mm. The pipes could be connected to one another after pulling in the pipes by means of split sleeves.
Wide bends could be made with pipe bending pliers, with these pliers one pressed notches closely next to each other into the inside of the desired bend, so that the pipe was shortened here and a bend was created. This can be clearly seen from the pipes that have been laid. According to the then valid regulations of the electrical trade, the fold of the metal jacket had to be on the outside or on the side facing the wall when making an arch so that the indented notches did not damage it. For narrow bends, branches and outlets, there were various, mostly hinged or dismantled accessories such as sleeves, angles, T-pieces and crosses as well as ceramic end grommets, which were intended to prevent the pipe end from damaging the hanging line.
A contemporary alternative to the Bergmannrohr was "Rohrdrraht, Kuhlo System " (also called folded wire ). In the case of the Kuhlo pipe , the rubber core cables were joined to the metal jacket, ie the metal jacket is wrapped tightly around the cable.
Bergmann pipes were primarily used for surface installation in dry rooms, but also for concealed installation. It was fastened with screw or nail clamps. Mining pipes were still in use after the Second World War, and in some cases even modern pipes insulated with plastic were laid in them.
Miner pipes have not been manufactured for a long time. They were replaced by installation pipes or installation ducts made of PVC or flame-retardant polypropylene . One of the reasons for this was the safety risk if the insulation failed at one point (for example a sheet metal edge); under certain circumstances the entire pipe system was then under mains voltage. Bergmann pipes were also not suitable for damp rooms, as the thin sheet material corroded quickly.
Most likely to be compared with miner pipes are galvanized steel armored pipes , also called StaPa pipes , which are still used today , which are used to lay cables in areas where reliable protection against mechanical stress is important, for example in industrial plants. However, the material is much stronger than that of the old Bergmann pipes.
See also
Cable laying , installation zone
Literature / sources
- A. Verduhn, W. Nell: Handbook of electrical engineering . Fachbuchverlag, Leipzig.
Individual evidence
- ↑ Steel tube, heavy 20.0x17.3 galvanized Staro Steck-ES-V20. From Eibmarkt.com, accessed January 8, 2019.