A heating coil is configured to inductively heat an inner surface of a tubular workpiece. The heating coil includes a head portion configured to be inserted into the workpiece and to inductively heat the inner surface of the workpiece, and a pair of lead portions connected to one end of the head portion and the other end of the head portion respectively. The head portion and the lead portions are configured as pipe members forming a series of flow channels through which coolant flows. A cross-sectional area of the flow channel inside each of the lead portion is greater than a cross-sectional area of the flow channel inside the head portion.

A heating coil includes a pair of linear lead portions adapted to be connected to a power supply, and a ring-shaped or coil-shaped head portion having end portions connected to the lead portions respectively. A flow path through which a cooling medium flows is formed inside the lead portions and the head portion. An outer circumferential surface of the head portion has a circular or elliptical cross section and is configured to face a heating target portion of an inner circumferential surface of a work extending, the heating target portion extending in a circumferential direction of the work. Each of the lead portions has a straight side portion in a plane intersecting a longitudinal direction of the lead portions, the straight side portions of the lead portions being arranged in proximity to each other.

A heating coil includes a pair of linear lead portions adapted to be connected to a power supply, and a ring-shaped or coil-shaped head portion having end portions connected to the lead portions respectively. A flow path through which a cooling medium flows is formed inside the lead portions and the head portion. An outer circumferential surface of the head portion has a circular or elliptical cross section and is configured to face a heating target portion of an inner circumferential surface of a work extending, the heating target portion extending in a circumferential direction of the work. Each of the lead portions has a straight side portion in a plane intersecting a longitudinal direction of the lead portions, the straight side portions of the lead portions being arranged in proximity to each other.

An induction coil unit for heating a sleeve portion of a tool holder which has a receiving opening for a shank of a rotary tool, the sleeve portion holds the shank of the tool seated in the opening in a press fit and releases it upon heating. The induction coil unit has a holding apparatus for holding the tool holder, a coil arrangement that encloses the sleeve portion during a heating operation, and a magnetic flux concentrator arrangement that is arranged near the free end of the sleeve portion. A detector for detecting a property of the tool holder held by the holding apparatus is provided. An actuator for adapting an operating parameter of the heating operation is further provided along with a controller that communicates with the detector to obtain data relating to the tool holder, and with the actuator to direct the adaptation of the operating parameter.

An induction coil unit for heating a sleeve portion of a tool holder which has a receiving opening for a shank of a rotary tool, the sleeve portion holds the shank of the tool seated in the opening in a press fit and releases it upon heating. The induction coil unit has a holding apparatus for holding the tool holder, a coil arrangement that encloses the sleeve portion during a heating operation, and a magnetic flux concentrator arrangement that is arranged near the free end of the sleeve portion. A detector for detecting a property of the tool holder held by the holding apparatus is provided. An actuator for adapting an operating parameter of the heating operation is further provided along with a controller that communicates with the detector to obtain data relating to the tool holder, and with the actuator to direct the adaptation of the operating parameter.

A method for manufacturing an induction coil assembly is disclosed. The method includes preparing a Computer Aided Design (CAD) model of an induction coil. The method further includes communicating the CAD model of the induction coil with a Three Dimensional (3D) printing machine The method further includes operating the 3D printing machine to deposit a plurality of layers of copper material one above other to manufacture the induction coil corresponding to the CAD model. The method further includes forming at least one hole in an annular member of the induction coil to receive a coolant and at least one hole in a first leg and a second leg to discharge the coolant.

An electrically heatable aerosol-generating system is provided, including an aerosol-generating device and a cartridge configured to be used with the aerosol-generating device, the aerosol-generating device including: a device housing, an inductor coil, and a power supply connected to the inductor coil and configured to provide a high-frequency oscillating current to the inductor coil; and the cartridge including: a cartridge housing configured to engage the device housing and containing an aerosol-forming substrate, the cartridge housing having an external surface surrounding the aerosol-forming substrate, and a fluid-permeable susceptor element. A cartridge for an electrically heatable aerosol-generating system is also provided.

An electrically heatable aerosol-generating system is provided, including an aerosol-generating device and a cartridge configured to be used with the aerosol-generating device, the aerosol-generating device including: a device housing, an inductor coil, and a power supply connected to the inductor coil and configured to provide a high-frequency oscillating current to the inductor coil; and the cartridge including: a cartridge housing configured to engage the device housing and containing an aerosol-forming substrate, the cartridge housing having an external surface surrounding the aerosol-forming substrate, and a fluid-permeable susceptor element. A cartridge for an electrically heatable aerosol-generating system is also provided.

There is described an aerosol-forming substrate for use in combination with an inductive heating device. The aerosol-forming substrate comprises a solid material which is capable of releasing volatile compounds that can form an aerosol upon heating of the aerosol-forming substrate and at least a first susceptor material for heating the aerosol-forming substrate. The at least first susceptor material is arranged in thermal proximity of the solid material. The aerosol-forming substrate further comprises at least a second susceptor material which has a second Curie-temperature which is lower than a first Curie-temperature of the first susceptor material. The second Curie-temperature of the second susceptor material corresponds to a predefined maximum heating temperature of the first susceptor material. There is also described an aerosol-delivery system.

There is described an aerosol-forming substrate for use in combination with an inductive heating device. The aerosol-forming substrate comprises a solid material which is capable of releasing volatile compounds that can form an aerosol upon heating of the aerosol-forming substrate and at least a first susceptor material for heating the aerosol-forming substrate. The at least first susceptor material is arranged in thermal proximity of the solid material. The aerosol-forming substrate further comprises at least a second susceptor material which has a second Curie-temperature which is lower than a first Curie-temperature of the first susceptor material. The second Curie-temperature of the second susceptor material corresponds to a predefined maximum heating temperature of the first susceptor material. There is also described an aerosol-delivery system.