초록 ▼

The induction preheating apparatus and methods of the present invention include a furnace for selectively preheating certain portions of irregularly shaped work objects prior to heating to a final uniform temperature in another furnace. The method includes selectively controlling the intensity of th

The induction preheating apparatus and methods of the present invention include a furnace for selectively preheating certain portions of irregularly shaped work objects prior to heating to a final uniform temperature in another furnace. The method includes selectively controlling the intensity of the induction magnetic field to provide magnetic field portions of higher intensity adjacent those portions of work objects tending to absorb less energy and magnetic field portions of lower intensity adjacent those portions of the work object tending to absorb energy at a higher rate. The method and apparatus of the present invention are used to achieve substantially uniform temperatures in irregularly shaped work objects after final heating in a main heating furnace.

대표청구항 ▼

In a method of heating an object to a substantially uniform temperature, said object having at least one portion tending to absorb energy at a higher rate when heated and at least one other portion tending to absorb energy at a lower rate when heated, the steps comprising: a. subjecting said portion

In a method of heating an object to a substantially uniform temperature, said object having at least one portion tending to absorb energy at a higher rate when heated and at least one other portion tending to absorb energy at a lower rate when heated, the steps comprising: a. subjecting said portions of said object of induction preheating in a magnetic field, produced by an energized induction coil having a plurality of turns and at least one robber coil having at least one turn and placed within the magnetic field produced by said energized induction coil in close proximity to said portion of said object tending to absorb energy at a higher rate, while said object is positioned at a predetermined position within said magnetic field; b. controlling said magnetic field in a manner to provide controlled portions including one magnetic field portion adjacent said portion of said object which tends to absorb energy at a lower rate, thereby heating said portion of said object to a predetermined temperature, and further including another magnetic field portion adjacent said portion of said object which tends to absorb energy at a higher rate, wherein said magnetic field portion is of lesser magnitude than the magnetic field portion first mentioned, thereby heating said portion tending to absorb energy at a higher rate to a temperature which is lower than said predetermined temperature first mentioned; c. continuing the induction preheating of said portions of said object to reach said different predetermined temperatures at said different portions of said object; d. removing said object from said magnetic field; and e. post-heating said object with a separate heating means to a substantially uniform temperature.