Abstract: A method for improving the heat transfer between an elongated electric resistance heating element and a pipe on which the heating element is mounted without use of heat transfer cement comprises utilizing a close fitting elongated rigid channel member to directly cover and press into direct contact with the outer surface of the pipe an elongated electric resistance element arranged lengthwise of the pipe. The heating element has a flat pipe contacting surface and comprises parallel resistance wires encased in a resilient electrically insulating sheath. The channel member is coextensive in length with the heating element and is pressed down against the heating element with substantially uniform pressure and contact to ensure that at least about 25% of the heating element is in continuous contact with the surface of the pipe. The channel member and heating element are entirely devoid of heat transfer cement.

Abstract: A high-temperature parallel-resistance pipe heater is described which is capable of being maintained at a high temperature level of approximately 600.degree. F on a sustained basis and is capable of withstanding temporary occasional heating up to 1,000.degree. F. A twisted pair of flexible electrical conductors with micaceous and fiberglass braid insulation layers have short segments stripped bare on alternate conductors at uniformly spaced intervals along their length, the conductors each including multiple fine nickel-clad copper strands, and a nickel-alloy resistance wire is helically wound around the twisted pair with two bights of the resistance wire engaging many of the strands in each bared segment for establishing numerous points of high unit area pressure contact at the junction between conductor and resistance wire. An anti-fraying agent on the fiberglass braid prevents the fibers from interfering with these points of contact.

Abstract: A high-temperature parallel-resistance pipe heater is described which is capable of being maintained at a high temperature level of approximately 600.degree. F on a sustained basis and is capable of withstanding temporary occasional heating up to 1,000.degree. F. A twisted pair of flexible electrical conductors with micaceous and fiberglass braid insulation layers have short segments stripped bare on alternate conductors at uniformly spaced intervals along their length, the conductors each including multiple fine nickel-clad copper strands, and a nickel-alloy resistance wire is helically wound around the twisted pair with two bights of the resistance wire engaging many of the strands in each bared segment for establishing numerous points of high unit area pressure contact at the junction between conductor and resistance wire. An anti-fraying agent on the fiberglass braid prevents the fibers from interfering with these points of contact.