Tokuden Jacket Roll®
With Tokuden's High Precision Induction - Heated Jacket Roll®, thermal processing precision is achieved in from cleanrooms to the production floor where oil heated rolls face substantial limitations.
When alternating current is applied to the induction coil, a magnetic field is produced. This creates an induced current inside the roll shell surrounding the coil, creating resistance heat, which heats the shell (induction heating). Unlike indirect heating systems, such as circulating oil or hot water, the induction-heated roll produces its own heat.
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Dozens of long thin holes (Jacket Chambers) are drilled in the roll shell that are parallel to the roll axis. An amount of thermal medium is vacuum sealed in each chamber, resulting in area of thermal medium and saturated vapor pressure. Vapor movement occurs continuously and any difference in temperature within the chambers is instantaneously rectified, thereby resulting in uniform temperature throughout the roll chambers and over the entire surface of the roll.
At a roll service temperature of 480°F roundness and cylindricity values are .0001. Even at 570°F mechanical accuracies are maintained at .0002. Temperature uniformity, across the face length of the roll, at 470°F is maintained at 1°F to 2°F.
