Abstract: Methods related to inductive heating in extruders. In some embodiments, a method for heating a feedstock or liquid material can include providing a heating body having inlet and outlet orifices connected via a passage or passages or mixing chamber to define a nozzle, and forming a magnetic loop with a coil of conductive wire wound through the center and around the outside of a core of magnetic but electrically non-conductive or low-conductivity material. The method can further include a high-frequency alternating current applied to the coil, producing a magnetic flux locally heating the nozzle. Some embodiments have passive regulation or limiting of nozzle temperature by selection of a core material with an appropriate Curie temperature.

Abstract: Methods related to inductive heating in extruders. In some embodiments, a method for heating a feedstock or liquid material can include providing a heating body having inlet and outlet orifices connected via a passage or passages or mixing chamber to define a nozzle, and forming a magnetic loop with a coil of conductive wire wound through the center and around the outside of a core of magnetic but electrically non-conductive or low-conductivity material. The method can further include a high-frequency alternating current applied to the coil, producing a magnetic flux locally heating the nozzle. Some embodiments have passive regulation or limiting of nozzle temperature by selection of a core material with an appropriate Curie temperature.

Abstract: One embodiment of a heated nozzle for extruding meltable material consists of an electrically conductive nozzle, comprised of an inlet, an outlet, and a passage connecting inlet and outlet. The nozzle fits into a hole or gap cut or formed through a loop of high permeability soft magnetic material such as ferrite or pressed iron powder. Electrically conductive wire is coiled around and through this magnetic loop to form a coil. A high-frequency alternating current is supplied to the coil, inducing a magnetic field in the magnetic core. The magnetic field, when passing through the electrically conductive nozzle, induces eddy currents that heat the nozzle to melt the material entering the inlet.

Abstract: One embodiment of a heated nozzle for extruding meltable material consists of an electrically conductive nozzle, comprised of an inlet, an outlet, and a passage connecting inlet and outlet. The nozzle fits into a hole or gap cut or formed through a loop of high permeability soft magnetic material such as ferrite or pressed iron powder. Electrically conductive wire is coiled around and through this magnetic loop to form a coil. A high-frequency alternating current is supplied to the coil, inducing a magnetic field in the magnetic core. The magnetic field, when passing through the electrically conductive nozzle, induces eddy currents that heat the nozzle to melt the material entering the inlet.

Abstract: One embodiment of a heated nozzle for extruding meltable material consists of an electrically conductive nozzle, comprised of an inlet, an outlet, and a passage connecting inlet and outlet. The nozzle fits into a hole or gap cut or formed through a loop of high permeability soft magnetic material such as ferrite or pressed iron powder. Electrically conductive wire is coiled around and through this magnetic loop to form a coil. A high-frequency alternating current is supplied to the coil, inducing a magnetic field in the magnetic core. The magnetic field, when passing through the electrically conductive nozzle, induces eddy currents that heat the nozzle to melt the material entering the inlet.