GROUND ROD FUR THE CONDUCTION

The invention concerns a ground rod for the electrical grounding with corrosion resistant an outside covering consisting of a leading material and from rod-shaped core existing another material. A such ground rod is already admits from the USA Patentschrfft Nr.589, 566. With this well-known ground rod the outside covering corrosion resistant consists of a completely sealed copper cylinder, in which a preferredwise core consisting of steel is taken up. This well-known ground rod is to that extent nachteiligù as the well-known arrangement, with which the more conductive in addition, softer material is arranged outside and the firmer however less Mtfähige material inside, to a quite unsatisfactory firmness and/or rigidity of the well-known ground rod leads. A further disadvantage of this ground rod is in it to be seen, Trade Union of German Employees fiir the outside cylinder considerable copper quantities to be needed, whereby a economical manufacturing of the well-known ground rod, in particular with at present extremely high copper price, is questioned. The invention is thus the basis the task to train a ground rod of the kind initially specified in such a way that optimal performance characteristics as well as economic advantages are attainable. This task is solved thereby that between the core, which consists of aluminum and which is intended outside HüUe an intermediate layer from a Werkstof£, standing in intimate contact with the core and the covering, which possesses a substantially larger firmness than aluminum. The advantage attainable with the help of the invention is to be seen primarily that owing to the erf'mdungsgemäßen structure of the Erduugsstabes excellent mechanical and electro-chemical characteristics as well as cost advantages are obtained. Furthermore considerable weight savings is attainable by the invention. After a favourable arrangement of the invention it is intended that the one large firmness consists exhibiting intermediate layer of Kohhnstoffstahl. The outside covering preferably consists of a rustproof steel. Furthermore it has itself as favourably gesture of out! it lt that the wall thickness of the covering is substantially smaller than the wall thickness of the one high firmness exhibiting intermediate layer. As previously mentioned, it was so far usual with multipart ground rods to locate on the exterior the material with the higher conductivity even if this material has a smaller firmness, whereas a material with higher firmness was arranged however smaller electrical Leitfähigkeitseigenscha£ten more to the staff inside. A such arrangement leads however to that considerable deflections must be taken in purchase, if such a ground rod is driven in the soil. The ground rod according to invention is based on the basic idea that the material with the smaller firmness can be arranged quite also in staff center, without affecting by it the conductivity of the Gesamtanordnung unfavorably, whereby the advantage is obtained that the rigidity of the ground rod is considerably increased. Becomes for example, as with the invention, which uses same aluminum cross-section area for the core, as with a pipe with an outside diameter of 14.4 mm and a wall thickness of 2.62 mm and the aluminum core becomes inside a carbon steel pipe and not within a Alumiuium pipe with the same cross-section area arranged, then the deflection amounts to for each load unit only 40.13 mm in relation to 51.51 mm at the mentioned comparison staff. In addition the weight 2.44 m of a long ground rod lets itself reduce by more than 450 p opposite ground rods, which have one approximated equivalent electrical resistance. If ground rods according to invention are compared with staffs by for instance the same Steiflgkeit however with higher electrical resistance, then the weight can be reduced even by more than 900 p. In addition it turned out that an aluminum pipe covered up by a pipe made of carbon is korrosionsaufällig and rusts, particularly since it represents a galvanic cell in itself. Such a pipe will thus work for many metals anodically, which are present in the earth and/or are used there. However it was found according to invention that an aluminum core, which is surrounded by an intermediate layer with high firmness, preferably consisting of a carbon steel, whereby this intermediate layer of korroslonsbeständägen and leading outside covering is surrounded, does not form in itself a galvanic cell and is also anodically not attacked in the soil rapidly. A such grounding bar arrangement is thus steady against the Korrosionsangrfff in the soil and can be worked on in a simple manner by braze welding or fusion welding. Summarized the advantages attainable with the help of the invention are therefore primarily in the fact that the ground rod is corrosion resistant and does not form in itself a galvanic cell, whereby in addition as favourable affects itself that the ground rod according to invention is very simply developed and can economically be manufactured. A remark example of the invention is represented and in the following is more near described in the design. The design partly shows on average a ground rod after the invention. As evident from the design, is with the reference symbol --2-- marked ground rod with a central Aluminiurnkern --4-- provided, which of a tubular intermediate layer --6--, which possesses a high firmness, is surrounded. This tubular intermediate layer --6-- is located in an extremely close contact to the aluminum core. The Zwischenschlcht --6-- consists of a leading material with a substantially larger firmness than aluminum. Preferably becomes as material for the intermediate layer --6-- an unalloyed carbon steel in form of a pipe uses. The intermediate layer is from a leading and outside covering corrosion resistant --8-- surrounded, whereby a close Materlalkontakt between the outside covering and the intermediate layer exists. After a preferential execution form the outside covering e.g. consists of a rustproof and/or stainless steel, like the USA steel grade 304, whereby the wall thickness of the outside covering however substantially smaller than the wall thickness of the Zwischenrohres --6-- is. An end of the ground rod --2-- can in usual way as Eintrelbspitze --10-- are trained. Alternatively the driving point can as separate workpiece with the ground rod be connected, or can the driving point, as in the design represented, einstückig with the Erdungsstah trained be. In each case the grounding point must be however incompletely with a covering from rustproof steel covered up. The tubular parts --6 and 8-- can in conventional way on the core --4-- drawn up its, whereby with as intermediate layer --6-- serving pipe one begins, which a somewhat larger inside diameter than the core --4-- possesses and an outside diameter has, which is somewhat smaller than the inside diameter of the outside covering --8--. A concrete remark example of the ground rod according to invention possessed a length of 2,22 m, whereby a core with a diameter of 11.1 mm from solid aluminum was intended, which was surrounded by 1.65 mm by a pipe from a carbon steel, serving as intermediate layer, with an outside diameter by 14.4 mm and a wall thickness. A pipe from a stainless steel with an outside diameter of 15.87 mm and a wall thickness of 0.74 mm, serving as outside covering, was drawn up on the Zwischenrohr. The ground rod possessed a resistance of 0,0006268 ohms and a weight of 2,58 kp.