Electric heater crushable cores and compacted unitary heater device and method of making such devices

An electric heater device for receiving material or devices to be heated comprising:

• a compacted core formed by crushing or swaging a crushable ceramic core comprising a cylinder-like body of crushable ceramic material,
• said cylinder-like body of crushable ceramic material having an inner wall, an outer wall, and key hole like longitudinal grooves with an entry along an inner circumference of said body, said key hole like longitudinal grooves in said crushable ceramic core that when considered in cross-section is rectangular or oblong or pillow shaped of greater width than said entry of said key hole like longitudinal grooves,
• said key hole like longitudinal grooves being each adapted to receive a conductive pin in said rectangular or oblong or pillow shaped cross-section, said conductive pin being approximately rectangular, each of said key hole like longitudinal grooves having an entry on said inner wall,
• wherein each said conductive pin is arranged in one of said key hole like longitudinal grooves, and conductive heater wire is wound on said crushable ceramic core, said conductive heater wire communicating with said approximately rectangular conductive pin,
• an inner sheath (30) with an inner and an outer metal circumferential wall and an outer sheath (29) with an inner and outer metal circumferential wall, wherein said inner sheath (30) and said outer sheath (29) enclose said crushable ceramic core,
• said outer metal circumferential wall of said inner sheath (30) defining a large diameter melt channel relative to a diameter of said outer sheath (29), a melt channel for delivering melted material or for containing or for containing a central pot (61) for holding heated material.