METHOD AND MEANS FOR SEGMENTALLY REDUCING HEAT OUTPUT IN A HEAT-TRACING PIPE

摘要

METHOD AND MEANS FOR SEGMENTALLY REDUCING HEAT OUTPUT IN A HEAT-TRACING PIPE This invention relates to an improvement in 2 heatgenerating pipe made up of a ferromagnetic pipe having an insulated conductor extending through it to a given point so that both the pipe and conductor may be connected in series with a power source of alternating current. The invention is directed to both a method and means for reducing the heat output over a desired segment of the pipe by reducing the magnetic field created by the alternating current flowing in the insulated conductor and that segment of the pipe. The means may be: a second electrical conductor internal and parallel to the heat reduced segment; 2 segment of nonferromagnetic electrically conductive pipe; an electrically nonconductive pipe extending throughout the desired segment shunted by a second conductor; or a portion of the insulated conductor that is exterior to the ferromagnetic pipe along the segment so that it is magnetically decoupled from the pipe in which a reduced heat output is desired. The method comprises the requisite steps of connecting an electromagnetic fielddecreasing means in the series circuit to reduce the alternating magnetic field produced in the pipe by the alternating current flowing through the conductor inside the pipe.