Making rod-shaped single crystals by horizontal solidifaction from a melt using transversally asymmetric trough-shaped resistance heater having transverse half turns

Claim 1

In a method of manufacturing rod-shaped single crystals from a starting material in the form of an elongate body positioned approximately horizontally by monocrystalline deposition in the longitudinal direction of said body from a melt formed at least in a longitudinal part of said body, the improvement which comprises forming said melt by heating said body with individually energizable heating elements at least one of which heating elements is not in contact with said body and has a transversally asymmetric position relative to said body, said transversally asymmetrically positioned heating element being trough-shaped thereby to allow for the heating of the lower side and upright sides of at least a longitudinal section of said body, said transversally asymmetric heating element comprising a substantially trough-shaped resistance heater having half turns extending transversally to the longitudinal direction of said body and the thermal energy, radiated by said element, being divided transversally in a substantially homogeneous manner over the inner side of the trough-shaped heating element and including a screen of a refractory material between the trough-shaped heating element and the bottom and sides of the body, said screen being out of contact with said body and any container for said body and being in a fixed position in regard to said heating element.