Apparatus for overheating the edges of a preheated formed skelp for the purpose of butt welding the skelp into pipe or tube. Induction coil assembly consisting of two (2) series connected loops, with a main conductor of each loop positioned within a magnetic flux guide and positioned adjacent to the open edges of the C-shaped skelp and the return conductors of each loop arranged externally on opposite side of the flux guide, providing localized overheating of the edges of the skelp prior to welding.

Apparatus for overheating edges of skelp for the production of compression welded pipe

Transverse flux heating of strip material is effected with a flux distribution having a low value near the margins of the strip and rising substantially uniformly inwardly from the margins to a central peak value for narrow strip or two peaks with a central lower flux region for wider strip Constructions of pole pieces to achieve the required flux distribution are described

Induction heating of strip and other elongate metal workpieces

A radio frequency induction heater for locally heating a metallic work piece. The induction heater comprises an elongated conductor surrounded by a core of magnetic material having a narrow slot formed therein serving as the inductor core air gap. The conductor is connected across a source of radio frequency current. The induction heater is located adjacent the metallic work piece with the inductor core air gap very near (and preferably in contact with) that portion of the metallic work piece to be heated. When the radio frequency current is caused to pass through the conductor, the gap concentrates the flux entering the work piece, inducing voltages in the work piece resulting in eddy currents which flow in the work piece along and parallel to the gap. This, in turn, results in the rapid local heating of a narrow band of the work piece.

Radio frequency induction heating device

An induction heater for heating a portion of a load comprises a side entry coil driven by a source of alternating current, with a flux concentrator located at the coil opening. The coil produces a magnetic field in the region occupied by the flux concentrator and the heated portion of the load. The flux concentrator extends along the opening of the coil and is fabricated of high permeability, low loss material, such as nickel-zinc ferrite, so as to enhance the uniformity of the magnetic field generated within the coil. In the preferred application, heating produces a complete fluid block in a cable section within the coil without overheating or damaging the cable.

Side entry coil induction heater with flux concentrator

Apparatus and method for drying or curing a coating on a metal substrate including inductivly heating the coated substrate in a highly confined space and condensing the evaporated liquid released as the result of the heating within the confined space at atmospheric pressure and room temperature. Ingress of atmospheric gases to the highly confined space is prevented without requiring locks or valves thus enabling a continuous flow of objects from the air into the highly confined space.

Apparatus and method for drying and curing coated substrates

A single-shot type inductor is provided with arrangements for selectively varying the current concentration along portions of the opposed faces of the inductor facing a workpiece therebetween. The arrangements provide for a single inductor to be employed to inductively heat workpieces which are of different contour, or to inductively heat different axial lengths of workpieces.

R Seyfried

Papers

Inductor for inductively heating metal workpieces