Patent ID: 7549462

Claim:
A reactor for treating a viscous medium or for carrying out chemical reactions in viscous medium, said reactor comprising: a vessel defining an inner volume; and a coil in said inner volume for circulation of a coolant fluid, said coil comprising a first segment of tube wound along a helical generatrix, and a second segment of tube wound along a helical generatrix and extending in parallel to the first segment between a distributor and a manifold, said first and second segments being centered on the same geometrical axis with substantially the same bending radius and nested so that they together form a substantially cylindrical bundle; wherein the distributor is located within said inner volume and is curved with a radius substantially equal to the bending radius; the distributor arranged substantially coaxially with the bundle; wherein the bundle constitutes a first bundle the coil further comprising a second bundle of cylindrical shape centered on said axis and curved with a radius different from said radius of said first bundle; wherein the coil further comprises a tube extending in a direction substantially parallel to said axis between said first and second bundles, said tube being connected either to said distributor or to said manifold.