High temperature diffusion furnace
AssigneeThermtec, Inc.
InventorsWilliam D. McEntire, Ronald E. Erickson
Life of this patent
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Abstract
The furnace 70 includes a heating element 72 which is restrained from growth during operation of the furnace 70 by retaining spacers 84 which provide a yoke 88 around the individual coils 102 of the heating element 72 and which spacers 84 are interlocked with each other. A high alumina fiber insulation 180 is applied to insulate the heating element 72. This high alumina fiber insulation 180 has enhanced properties with respect to shrinkage and devitrification.
Claims23
An electric furnace having a electric heating element and insulation covering said heating element, the furnace comprising:
- said insulation having:
- at least a first layer placed adjacent to heating element which is comprised of at least 75% alumina and the remainder silica;
- and
- at least another layer placed adjacent the first layer which is about 50% alumina and 50% silica.
An electric furnace having a heating element comprised of an elongate wire formed into a plurality of individual coils comprising:
- a plurality of heating element retention spacers for keeping the coils of said wire spaced apart;
- each of said spacer including:
- (a) first means for providing a yoke about the wire of each coil;
- (b) a second means for interlocking one of said spacers to another of said spacers in order to maintain the position of each coil relative to the next adjacent coil and relative to the furnace;
- and
- insulation means for covering, insulating and assisting in the positioning of the heating element including:
- (a) at least a first layer placed adjacent to the heating element which is comprised of at least 75% alumina and at least the remainder silica;
- and
- (b) at least another layer placed adjacent the first layer which is about 50% alumina and 50% silica;
- so that the spacers and said insulation means confine growth of said electric heating element as said electric furnaces is repeatedly used.
Dependencies are inferred from the claim text.