Electromagnetically shielded induction heating apparatus

An induction heating apparatus comprising a substantially gas-tight enclosure through which a workpiece passes, and an induction means disposed around the outside of the enclosure to carry an ac current for generating a magnetic field that penetrates the enclosure and inductively heats the workpiece passing through the enclosure,

• the improvement comprising,
• the substantially gas-tight enclosure comprising a non-electrically conductive material to permit coupling of the magnetic field with the workpiece passing through the enclosure and an electromagnetic shield material disposed within the non-electrically conductive material for restricting the regions of the magnetic field.

An induction heating apparatus comprising a substantially gas-tight enclosure through which a workpiece passes, and an induction means disposed around the outside of the enclosure to carry an ac current for generating a magnetic field that penetrates the enclosure and inductively heats the workpiece passing through the enclosure,

• the improvement comprising,
• the substantially gas-tight enclosure comprising a non-electrically conductive material to permit coupling of the magnetic field with the workpiece passing through the enclosure and at least one electromagnetic shunt disposed around the induction means to restrict the magnetic field in a direction towards the workpiece.

An electric induction heating apparatus comprising a substantially gas-tight enclosure through which a workpiece passes, and an induction heating inductor disposed around the outside of the enclosure through which an ac current flows to generate a magnetic field that penetrates through the enclosure and inductively heats the workpiece passing through the enclosure,

• the improvement comprising,
• the substantially gas-tight enclosure comprising a non-electrically conductive material to permit coupling of the magnetic field with the workpiece passing through the enclosure, the non-electrically conductive material having at least one flexible element for movement of the gas-tight enclosure in the upstream and downstream directions of the enclosure.

An induction heating apparatus comprising a substantially gas-tight enclosure through which a workpiece passes, and an induction means disposed around the outside of the enclosure to carry an ac current for generating a magnetic field that penetrates the enclosure and inductively heats the workpiece passing through the enclosure,

• the improvement comprising,
• the substantially gas-tight enclosure comprising a non-electrically conductive material to permit coupling of the magnetic field with the workpiece passing through the enclosure, the non-electrically conductive material having at least one flexible element for movement of the gas-tight enclosure in the upstream and downstream directions of the enclosure, and at least one electromagnetic shunt disposed around the induction means to restrict the magnetic field in a direction towards the workpiece.