Inductively heated drawroll

A heatable drawroll for draw-twisting, draw-winding and spin-draw-winding machines comprising

• a rotatable drive shaft,
• a jacket secured to said shaft for rotation,
• a stationary heating means within said jacket including a magnetically conductive core and a plurality of induction coils about said core,
• a sleeve of heat and electrical insulating material stationarily disposed within said jacket in radially spaced relation to said jacket and said coils to circumferentially surround said coils and form an intermediate space therewith,
• at least one supply duct extending through said heating means into said space for supplying a coolant thereto, and
• at least one drain opening extending through said heating means from said space for draining coolant therefrom.

A heatable drawroll for heating a travelling yarn comprising

• a rotatable jacket;
• a stationary inductive heating means mounted inside said jacket for heating said jacket, said heating means including an induction coil, an annular space disposed about said coil, a sleeve of heat and electrical insulating material disposed inside said jacket in radially spaced relation to said jacket and said coil and a pair of discs of heat and electrical insulating material, each disc supporting a respective end of said sleeve at a respective end of said coil, said sleeve and said discs defining together with said coil said annular space;
• and
• means for supplying and removing coolant to and from said space to cool said coil.