Abstract: A flexible radiant tube heater is disclosed herein which is particularly useful in thermally stress-relieving the U-bend sections of the heat exchange tubes within nuclear steam generators. The apparatus generally comprises an elongated, flexible mandrel formed from a spring composed of a heat-resistant alloy, a flexible electrical resistance heating element wound around the mandrel spring, and a flexible insulating sleeve formed from braided alumina fibers disposed around the heating element for electrically insulating the heating element from both the metallic spring and the inner walls of the tube. A nosepiece assembly and an endpiece are disposed on the front and back ends of the spring, respectively. A flexible reinforcing member which may be a thin rod of Inconel.TM. is mounted to both the nosepiece assembly and the endpiece and disposed through the windings of the mandrel coil in order to lend more tensile and compressive strength to the mandrel coil.

Abstract: Small portable electrical resistance heated radiant heating unit useful for insertion in tube bores to effect localized high temperature heating. Useful for the internal heating of tubes and tube/sleeve assemblies in steam generators, for brazing, stress relieving, and other applications. Has a machined mandrel of boron nitride and electrical resistance wire leads that have reduced electrical resistance for reduced heat generation by the leads. The leads preferably are braided, to permit the use of cramped connectors.

Abstract: The brazing wand comprises a hollow helically wound electrically conductive tubular member for conducting an electrical current and for conducting a coolant therethrough. The electrical current is used to heat a member to be brazed while the coolant is used to control the temperature of the brazing wand. The brazing wand also comprises a flexible cable for conducting the electrical current and coolant to the heating portion of the wand.