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AssigneeTSL Group PLC
InventorsRobert Nicholson, Bernard Phillipe Robert Poullain, Ian George Sayce
Estimating the term…
An induction-heated furnace, suitable for heat treatment of synthetic silica bodies, under conditions of high purity, includes a tubular susceptor (1) disposed with its axis vertical and an induction coil (3) for raising the temperature of the susceptor. The susceptor is made from graphite and/or silicon carbide, and is enclosed within a vacuum envelope (2) made from vitreous silica or fused quartz, the envelope being surrounded by the induction coil which is liquid-cooled. The design is such that the vacuum envelope (2) operates at temperatures below those at which either devitrification or sagging of the envelope might occur even when the tubular susceptor (1) is heated to a temperature of 1700.degree. C. Thus sintering of a porous synthetic silica body (9) can be carried out under atmospheric or reduced pressure, the furnace including a shaft (7) adapted to support the body to be heated and capable of rotation about and movement along said vertical axis of the tubular susceptor (1).
An induction heated furnace for heat treatment and/or sintering of synthetic silica bodies, under conditions of high purity comprising a tubular susceptor having an inner surface, the susceptor having a longitudinal axis extending vertically, means, located along said longitudinal axis, for supporting a synthetic silica body within the susceptor on said longitudinal axis but spaced from the inner surface of the susceptor, the susceptor being made from graphite and/or silicon carbide, means, comprising a gas-impermeable enclosure, for containing a vacuum or gas serving as an environment for the synthetic silica body during heat treatment and/or sintering, the enclosure being formed at least in part by an envelope surrounding the susceptor, the envelope being made from vitreous silica or fused quartz and serving to contain said environment, and the envelope and the susceptor both being surrounded by a liquid-cooled induction coil for raising the temperature of the susceptor, and closure means for closing said enclosure and maintaining said environment, wherein the envelope operates at temperatures below those at which either devitrification or sagging of the envelope can occur, whereby heat treatment and/or sintering of a porous synthetic silica body can be carried out under atmospheric or reduced pressure.
Dependencies are inferred from the claim text.