| 摘要 |
A pipeline to be laid over a very long distance e.g. 100 km, and heated by skin-effect-current, and used underground or on the seabed by employing an electric source frequency lower than commercial ones, is provided. The pipeline consists of a fluid-transporting pipe and a heat-generating pipe utilizing skin effect current laid so as to trace said fluid-transporting pipe (which will be referred to herein as SECT pipe). The SECT pipe consists of a ferromagnetic pipe and an insulated electric wire passed therethrough, and has a special circuit, and the pipeline is further provided with an outer covering pipe of a ferromagnetic material so as to enclose the fluid-transporting pipe and the SECT pipe. The covering pipe is electrically connected to at least both end portions of the SECT pipe and the thickness of the outer covering pipe is so devised that an alternating current having leaked out of the SECT pipe substantially does not appear on the outside of the outer covering pipe, but flows only through the inner skin portion thereof. |
