Abstract: A stacked type heater construction particularly suitable for large HIP apparatus, having a number of heating unit assemblies stacked one on another to provide a vertical series of independently controllable heating zones, the heater including a generally cylindrical heater retaining cage constituted by a number of annular graphitic members serving as girdle frames and a number of graphitic support columns serving as vertical frames, the annular members and support columns being connected with each other through electric insulators and defining a series of divided sections around the heater retaining cage in each one of the heating zones; and a plurality of segmental graphitic heating elements supported in the respective divided sections of the heater retaining cage through electric insulators to form an independent heating circuit in each heating zone.

Abstract: An apparatus for heating a workpiece at elevated temperatures both under vacuum and under superatmospheric pressures comprises a vacuum pressure vessel comprising a cylindrical pressure shell having an inner cylindrical sealing face near the upper edge thereof and a cover at one axial end and a bottom plug at the other axial end. Both are arranged to be placed within a reaction frame bearing thereupon. A furnace within the shell has an insulating hood for protecting the shell from the heated workspace. A vacuum manifold is mounted to the top edge of the cylindrical shell and is sealed thereto. The manifold has a cylindrical interior through which the cover passes and an inner cylindrical sealing face at the upper end thereof. Mechanically powered means are provided for raising and lowering the cover and placing it in a first or a second position.

Abstract: An arrangement for mounting and insulating strip sheet heating elements in the heated interior of vaccum furnaces comprises a plurality of rods secured at one end to a support liner and supporting at their other ends a heating element assembly which includes a heating element, insulators, retaining or locating pins and a reinforcing member for the heating element. The arrangement may also include means for transferring quenching gases to the interior working space of vacuum furnaces, consisting of an integral manifold or plenum support ring assembly and a plurality of locked in tubes which route the gases directly into the working section of the furnace.

Abstract: A furnace producing a precisely controlled temperature gradient within a central bore by a plurality of heating elements sandwiched between respective insulating layers with each heating element loosely thermally coupled to a thermally conductive ring extending concentrically outward from the furnace bore. Thermal sensors at each layer provide data to data processing equipment which controls and moves temperature gradients within the furnace by program.

Abstract: Muffle furnace having an elongated metallic muffle extending through several heating zones of the furnace. Temperature of muffle is measured at different parts thereof. In order to minimize the difference of temperature which causes the deformation of muffle, heaters of furnace are controlled coincidentally so as to compensate said difference.