Abstract: A method and apparatus for vacuum purging bell type furnaces is provided. A vacuum shell unit is provided which is removably emplacible over the inner cover of the furnace and has a vacuum tight seal to the base. A vacuum is pulled both within the inner cover and within the vacuum shell to remove the ambient gas. Nitrogen is then introduced into the inner cover and within the vacuum shell. The vacuum shell is then removed and purging continues within the inner cover either with nitrogen or other desired atmosphere gas, and finally furnace is emplaced over the inner cover to heat treat the work in a conventional manner.

Abstract: An improved heat transfer arrangement for use in a unique multi-function, industrial heat treat furnace which employs a sealed, closed end, heat exchanger shell member containing the work. The heat transfer arrangement includes a totally contained, internal recirculation system which develops an especially configured annular jet stream that produces highly efficient, convective heat transfer with the shell member. After heat transfer between the entrained gases in the jet stream with the shell member has occurred, the jet flow is reversed at one end of the shell and impinged against the workpiece, the spent stream being reformed into the annular jet at the opposite end of the shell member.

Abstract: An improved heat transfer arrangement for use in a unique multi-function, industrial heat treat furnace which employs a sealed, closed end, heat exchanger shell member containing the work. The heat transfer arrangement includes a totally contained, internal recirculation system which develops an especially configured annular jet stream that produces highly efficient, convective heat transfer with the shell member. After heat transfer between the entrained gases in the jet stream with the shell member has occurred, the jet flow is reversed at one end of the shell and impinged against the workpiece, the spent stream being reformed into the annular jet at the opposite end of the shell member.

Abstract: A seal arrangement is disclosed for use in a furnance which utilizes a thin, cylindrical imperforate shell member which is heated from an external source to heat work placed within the shell. An insulated arrangement within and outside of the shell extends a spaced distance from the shell's opening to sandwich the shell's wall therebetween. The arrangement prevents heat flux by radiation and convection from heating the sandwiched wall thus permitting graded cooling of the sandwiched shell wall by conduction to a temperature whereat a conventional elastomer seal can be employed to seal the shell member.

Abstract: A furnace for heat treatment in vacuo with cooling by a stream of gas wherein there is a rotating volute mounted between a heat enclosure and a turbine and wherein the rotating volute is in the form of a helical flange arranged on the outside of a hollow cylinder through which gas is directed from the enclosure to the turbine and which volute also includes a gas outlet deflector associated with the helical flange through which gas may be directed toward the heat enclosure.

Abstract: Apparatus for treating workpieces under the action of hot gases within a chamber in order to achieve as homogeneous a treatment or processing as possible are provided with a valve mechanism whereby the gas is made to flow alternately from one side to the other over objects or workpieces within the chamber, the valve mechanism being especially designed to operate with heated gases and serving to reverse the gas flow.

Abstract: A thermopulse apparatus for deburring parts has a hollow body (1) housing a working chamber (2) in such a manner as to define a space (7) between the outer walls (6) thereof and inner walls (4) of the body (1) for liquid (8) partly filling the space. The chamber (2) has spark plugs (9), an inlet valve (20), an exhaust valve (12) mounted in the bottom part of the chamber (2) along the longitudinal axis (16) thereof under the layer of liquid (8), and a covermember (13) for accommodation of the parts (14) being treated, the convermember being reciprocatable within the chamber (2). Ports (23 and 32) respectively are provided in the side walls (22) of the valve (12) and in the covermember (13) on the side of the valve (12).

Abstract: An apparatus for thermal deburring of parts has a working chamber (6) with a bottom member (3), an inlet valve (8), a spark plug (9) and an outlet valve. The latter is made in the form of a rod (10) having a through passage (11), one end of the passage communicating with the interior of the chamber (6) and the other end being disposed in a vessel (1) containing a liquid (2) and surrounded by an annular cooling chamber (13).

Abstract: An apparatus has a cylindrical working chamber (2) with a bottom member (7) provided with admission and discharge valves (3,5) and a spark plug (4). The bottom member (7) is made as a hollow cylinder having end plates and openings (8), the height and outside diameter of which are approximately equal to the height and inside diameter of the working chamber (2). Sealing rings (11, 12) are interposed between the chamber (2) and the hollow cylinder.

Abstract: A seal arrangement is disclosed for use in a furnace which utilizes a thin, cylindrical imperforate shell member which is heated from an external source to heat work placed within the shell. An insulated arrangement within and outside of the shell extends a spaced distance from the shell's opening to sandwich the shell's wall therebetween. The arrangement prevents heat flux by radiation and convection from heating the sandwiched wall thus permitting graded cooling of the sandwiched shell wall by conduction to a temperature whereat a conventional elastomer seal can be employed to seal the shell member.

Abstract: A heat treatment apparatus which comprises a treatment chamber formed with heat insulating walls, a graphite heater installed in the treatment chamber, a gas supply port supplying non-oxidizing gas to the chamber and an exhaust port for carrying gas out of the chamber. At least a part of the inner side of the heat insulating walls is made of graphite group material of bulk density of not less than 0.3 g/cm.sup.3. The ratio of the outer surface area of the graphite heater (Ah) to the surface area of the chamber-facing side of the heat insulating walls (Ai), Ah/Ai is within the range of 0.1-0.4, and the relationship between the surface area of the graphite group material (Ar) and (Ah) is Ar>Ah. By this structure, the temperature of the heater to be set for heat treatment of workpieces can be decreased, and the life spans of the heater and the heat insulating walls can be increased.

Abstract: A heat treating apparatus which comprises a core tube for containing a material to be treated, a heating furnace surrounding the core tube, core tube gas supply means for supplying gas into the core tube, furnace gas supply means for supplying gas into a furnace body of the furnace, differential pressure detecting means for detecting the differential pressure between the pressure in the core tube and the gas pressure in the body, and differential pressure regulating means for regulating the differential pressure between the gas pressure in the core tube and the gas pressure in the body on the basis of a differential pressure signal from the detecting means. The apparatus is operated by regulating the gas pressure in the core tube so that the differential pressure between the gas pressure in the core tube and the gas pressure in the body fall within a tolerable range, thereby preventing the core tube from deforming.

Abstract: A gas feeding device is suggested which is used for feeding a combustible gas mixture consisting of at least two components into a combustion chamber of a thermic deburring installation for treating work pieces (3) by means of temperature and pressure shocked formed by igniting the gas mixture. The device includes a control circuit used as a dosaging device which is adjustable to different mixing ratios. The central circuit includes a through flow amount meter in each of the gas feeding lines, a measuring value comparator (31) and a dosaging valve controlled by the measuring value comparator in one of the feeding lines. Shut-off valves are provided in the feeding lines between the flow amount meters and the combustion chamber which react to a signal issued by a storage or counting device connected to one of the flow amount meters (24 or 29) in response to the flow of a preselectable amount of gas.

Abstract: The disclosure relates to a system for removing binder from "green" bodies wherein debinding action takes place substantially uniformly throughout the sytem for large load as well as for small loads. This result is obtained by providing a plurality of shelves for holding the parts and providing turbulent atmosphere flow across all shelves with recirculation taking palce over a water fall in the system to provide both a water saturated atmosphere and removal of binder from the atmosphere and system simultaneously.

Abstract: A vacuum furnace for heating dental reconstructionproducts using sintered powder metal that includes a sealed vacuum tube made of a material having a relatively low thermal shock resistance characteristic. The vacuum tube is desirably relatively short. The vacuum tube chamber has a heating chamber and end seals for the vacuum tube have a maximum use temperature of less than 200.degree. C. Insulation is positioned around and connected to the tube proximate the ends of the tube, and heating elements are placed around the heating chamber in an annular insulation chamber formed in the insulation between the insulation and the vacuum tube. Opposed annular clearances extending to positions proximately spaced from the ends of the tube and opening to the central annular insulation chamber are formed between the insulation means and the vacuum tube. The insulation prevents heat from passing to the ends of the tube and overheating the seals there.

Abstract: A casting (e.g. of aluminum or aluminum alloy) is made at least approximately free from pores by being subjected, in heated state, to isostatic compression in a liquid pressure medium. A rapid pressing operation of under one minute can be achieved if the casting is placed in a container, the container and the casting are heated to the required compression temperature before they are thereafter placed in a press chamber of a fast-acting press. When liquid pressure medium is fed to the press chamber and the necessary pressure is applied thereto, the pressure medium flows into the interior of the container via a number of channels in its wall and is simultaneously heated to the necessary temperature, prior to its contacting the casting.

Abstract: Apparatus for the cooling of articles which have been subjected to an isostatic pressing process is provided. The apparatus includes an injector system which is connected with a fresh gas supply conduit, and with passages along which the gases are drawn from the interior of the apparatus by the injector system, all in such a manner that a circulation of gas can be maintained in the pressure chamber, primarily between the top and bottom regions of the apparatus.

Abstract: A method and apparatus for heating semiconductor wafers characterized by the release of preheated nitrogen into an oven to considerably reduce heating time for the wafers. The oven is evacuated prior to the release of the preheated nitrogen.

Abstract: An apparatus for heat treating a work item includes a cover member and a base member on which the cover member is supported. A work space is defined between the base member and the cover member for receiving at least one work item which is positioned therein. A seal member is located between the base member and the cover member for sealing the work space against the entry and exit of gas. A valving system is provided for regulating the entrance and exit of a gas to and from the work space. The valving system is in fluid communication with the work space and includes a relief valve member for allowing the exhaust of the gas from the work space when gas pressure therein exceeds a predetermined limit.

Abstract: In an apparatus for treating workpieces by means of the igniting of a gaseous mixture in a work chamber for receiving the workpiece, it is proposed that the work chamber and optionally the supply duct for the gaseous mixture, as well as a mixing block for preparing the gaseous mixture which precedes the supply duct, are provided at least in part with a lining of ceramic material in the form of aluminum oxide or zirconium dioxide, in order to intercept the corrosive action exerted by the ignition of the combustion gas-oxygen mixture upon these parts of the apparatus.

Abstract: A device is suggested wherein the work piece finishing chamber (31) serves simultaneously as a mixing chamber for mixing the gas components, and wherein a gas deceleration stage (47) is integrated in chamber block (30) between chamber (31) and a spark plug (54). The gas deceleration stage (47) is provided with labyrinth like extending bores (49,50,51). The combustion residues generated in the work piece finishing chamber (31) cannot reach spark plug (54) in view of the gas deceleration stage (47). Thus, a contamination of the spark plug (54) being disposed in block (30) is substantially eliminated.

Abstract: A nozzle for delivering cooling gas into the work chamber of a heat treating furnace. The nozzle is formed by a resiliently yieldable metal tube having an overlapping seam and adapted to be contracted radially for insertion through a hole in the wall of the work chamber. After being inserted through the hole, the tube springs outwardly into frictional engagement with the edge of the hole to retain itself in place. Flares on the ends of the tube prevent the tube from shifting endwise relative to the chamber wall.

Abstract: An apparatus for gas pressure bonding, hot isostatic pressing or the like in which a workpiece may be treated at elevated temperatures and pressures comprises an elongate cylindrical pressure vessel for enclosing a furnace. The furnace comprises an insulated bottom and an insulated hood with openings near the top and bottom. The insulating hood rests upon the bottom for enclosing a workspace. Means for heating the workspace and means for cooling the pressure vessel are provided. The improvements according to this disclosure are means for establishing a first circulating flow of pressurized fluid down along the interior of the pressure vessel wall, means for establishing a second circulating flow of pressurized fluid down through the workspace.

Abstract: The disclosure relates to a vacuum sintering furnace having a lubricant eliminating section, sintering section and cooling section which are aligned in series and connected by connecting hood means to each other so that a workpiece may be directly transferred to the following section without exposure of the workpiece to outside air. The connecting hood means comprises doors for selectively opening and closing the boundaries between the neighboring sections. Furthermore, the lubricant eliminating section is provided with a lubricant trapping device mounted on an exhaust line connecting a furnace body and a vacuum pump to each other, thereby the stable operation of the vacuum pump is ensured.

Abstract: The present invention includes a heat insulation wall which is formed in a closed plane configuration, such as a circle, and which has first and second pairs of apertures formed therein to accommodate cooling (inert) gases which are introduced into the heat chamber defined by said insulation wall. The cooling gases pass into the heat chamber and out of the heat chamber through the first and second pairs of apertures to cool a workpiece which has been heat treated. The pairs of apertures lie (in pairs) opposite one another on the periphery of the heat insulation wall. Outside of the heat insulation wall, lying opposite the first pair of apertures, is located a heat reflecting member and opposite the second pair of apertures, outside of the heat insulation wall, there is located a heat reflecting baffle. Accordingly when the heat chamber is operating in a heat treating mode any heat which passes through an aperture or a pair of apertures is reflected back through said apertures into the heat chamber.

Abstract: The present invention provides, among other things, a plenum which is formed around the hot zone chamber of a vacuum furnace and which has a common wall with the hot zone chamber. The present arrangement includes having a plurality of apertures formed in the common wall and a plurality of baffles, or deflecting means, secured to the common wall within the chamber of the plenum. The baffles, or deflecting means, are formed to be angular with respect to the common wall and each deflecting means is disposed and formed to deflect gas (in all likelihood, inert gas), passing through the plenum, into and through an associated aperture and thereby into the hot zone chamber. By using the baffles, the inert gas, which is fed into the hot zone chamber from the plenum, is so fed with improved and significant uniformity.

Abstract: A process for making stacked high voltage rectifiers includes initially doping a plurality of silicon wafers with paint-on dopants applied with an applicator that is gradually moved from the center to the outer edge of each wafer while the wafer is peripherally supported and rotated sufficiently slowly to prevent spin-off and runover of each dopant onto the reverse side of the wafer. The dopants are driven in by heating in a diffusion furnace. The same slow rotation and moving applicator technique then is used to coat only the N-doped side of the wafer with a paint-on noble metal dopant. The noble metal is driven in using a diffusion furnace at a temperature that is selected in accordance with the measured reverse recovery time of the wafer prior to noble metal diffusion.The wafers are silver coated and stacked, and a compression jig is used to exert compressive force on the stack while it is heated in an alloying furnace to a temperature sufficiently high to cause "wetting" of the silver.

Abstract: To separate combustion within a combustion chamber for deburring or high-temperature, high-pressure article treatment from gas supply valves, the combustion chamber is formed of a dual wall structure, having an outer wall (21) which is telescopically slidable with respect to an inner wall (12). The articles are introduced into the chamber (11) by placing a support plate (14) against the outer wall structure, with the inner wall (12) slightly raised, leaving a gap (23) between the lower edge of the inner wall and the support plate. Gas introduced within the outer wall structure than can pass into the chamber (11) within the inner wall, through said gap. When the requisite volume and pressure of fill gas--typically oxygen and a combustion gas such as hydrogen, methane or the like--is within the chamber, the inner wall (12) is lowered into sealing engagement with the support plate (14), for ignition of the combustible mixture.

Abstract: To permit installation of various sizes of deburring chambers, matched to particular sizes, or combination of sizes of workpieces, so that only the minimum size chamber for the particular quantity or size of workpiece need be used, the chambers are provided in sets with adapters so that a single machine frame can be utilized, the adapters and chambers being fitted within the machine frame so that the lower edge (13a, 13'a) of any one of the chambers is within the closing or sealing stroke of a closing plate (14) carrying the workpieces. A coding system, for example coding bolts (16) is secured to each one of the chambers, to be scanned by a reading head (17) and transmitting information relative to the appropriate fill quantity and pressure of gases for the particular chamber then being installed in the machine.

Abstract: In an apparatus for thermal treatment of semiconductors in a treating gas, a treating tube has a heating portion, an extending portion, and a sealing portion, and convection-preventing plates are disposed within a treating tube, between one end of the heating portion and the sealing portion, so as to interrupt currents of the treating gas. A heating element is arranged so that the quantities of heat generated along the heating portion are largest near a gas-discharging end of the heating portion, intermediate near a gas-discharging end thereof, and smallest therebetween. The plates are mounted to the sealing portion so as to be inserted into the treating tube when the sealing portion is attached and so as to be withdrawn from the treating tube when the sealing portion is detached. The plates may be mounted integrally to the sealing portion.

Abstract: A heater which includes: at least two electrically conductive heating element units having generally a self-standing cylindrical shape and stacked one on another to define a series of at least two cylindrical heating zones, the heating element units each including of a grid-like structure alternately having a vertically disposed portion and a horizontally extending bridge portion; insulator blocks fitted on the ends of stacked upper and lower cylindrical heating element units which meet and which are made of a material having a sufficient electric resistance that will not conduct electric current at a maximum operating temperature of the heating element units; and an annular shaped connector conforming with the ends of the upper and lower heating element units which meet and which is interposed between the insulating blocks on the ends which meet to provide a mechanical connection between the stacked upper and lower heating element units.

Abstract: The vacuum chamber includes an airtight generally cylindrical wall and a pair of end members. Vacuum pumps in the chamber evacuate the chamber. The chamber is rotated along the longitudinal axis whereby the centrifugal force of the rotating cylindrical wall acts against the force resulting from the pressure differential between the inside of the evaluated chamber and ambient pressure on the outside of the cylindrical wall to prevent the cylindrical wall from collapsing. An inner member is mounted in the chamber, but the chamber rotates with respect to the inner member. In a low temperature embodiment for freeze drying refrigerated air cools the outside of the chamber to reduce the temperature within the chamber. The consensables condense on the inside of the cold cylindrical wall.

Abstract: A semi-continuous vacuum heat-treating furnace of two-chambers and one-door type is composed of a vacuum heating chamber which includes a heating element and a heat insulation material, both being stable in chemical property and strength in vacuum condition and atmospheric pressure at high temperature, a cooling chamber which is associated with the vacuum heating chamber, and an intermediate vacuum door which separates the vacuum heating chamber and the cooling chamber from each other.

Abstract: The vacuum chamber includes an airtight generally cylindrical wall and a pair of end members. Vacuum pumps in the chamber evacuate the chamber. The chamber is rotated along the longitudinal axis whereby the centrifugal force of the rotating cylindrical wall acts against the force resulting from the pressure differential between the inside of the evaluated chamber and ambient pressure on the outside of the cylindrical wall to prevent the cylindrical wall from collapsing. An inner member is mounted in the chamber, but the chamber rotates with respect to the inner member. In a low temperature embodiment for freeze drying refrigerated air cools the outside of the chamber to reduce the temperature within the chamber. The consensables condense on the inside of the cold cylindrical wall.

Abstract: A process for hot isostatic pressing of a metal workpiece, such as a ferrous casting. The workpiece is heated in a fluidized particulate bed (sand) to a temperature above the plastic range of the metal (e.g. 2000.degree. F.). Then, the workpiece in the unfluidized bed at this temperature is subjected to a superatmospheric gas pressure above 20,000 psi until internal mechanical property changes have occurred. Lastly, the workpiece is removed from the bed and superatmospheric pressure environment for subsequent utilization.

Abstract: In a kiln for firing ceramic workpieces, which kiln is composed of two opposed side walls and a top wall enclosing an elongate kiln chamber, and elements for introducing jets of heating or cooling gases into the kiln chamber at locations spaced along the length of the kiln, the elements are located for directing the jets produced thereby vertically in the region of the side walls of the kiln, and deflector stones are disposed at a distance from the elements for deflecting the jets and gases within the chamber transversely of the length of the kiln.

Abstract: A furnace is described as having a heat treatment chamber which is provided with banks of radiant heaters to heat a load that is placed within the chamber for heat treatment. The radiant heating of the load is improved by the addition of convection heating which is carried out by a plurality of nozzles that are designed to direct jets or streams of heated gas against the load positioned in the chamber.

Abstract: An elevated pressure reactor apparatus for oxidizing or annealing specimens of the type including a reaction tube for containing the specimen surrounded by a heating furnace and enclosed in a pressure chamber, the apparatus incorporating a unique single gas flow feature, an improved multi-element furnace structure, a retrograde closure for the reaction tube to prevent gas flow back from the pressure chamber, a magnetically connected driving mechanism for a specimen support boat, and concentric gas entrance and exit tubes wherein exiting gas pre-heats the entering gas.

Abstract: An apparatus for treating articles by heat and pressure and then cooling by forced circulation may have a pressurized heated chamber for holding such items to be treated, this chamber being positioned within a cooled, pressure sustaining enclosure, a pressure developing mechanism may be positioned at one side of this enclosure and may include a valving function for selectively drawing inert gas into the enclosure and into the heated chamber the heated chamber including a wall having a plurality of openings spaced throughout into the item-holding chamber, a passageway may extend from one end of this item-holding chamber, past the cooled area of the sustaining enclosure and onto the pressure developing mechanism whereby the valving function may be selectively operated allowing the pressure developing mechanism to circulate the gaseous medium within the apparatus more evenly and uniformly over all items held within the chamber, the heating operation of the chamber being selectively disabled during this circulati

Abstract: A furnace having an easily disassembled vacuum chamber to facilitate muffle replacement. The muffle is located over pins on the vacuum chamber base and is held against the base by a leaf spring between the muffle and the vacuum chamber top. The cylindrical wall of the vacuum chamber is correctly located with respect to the muffle by upright spacer bars upstanding from the vacuum chamber base about the periphery of the cylindrical wall. The spacer bars further serve to tie the top and base of the vacuum chamber together and against the cylindrical wall. The furnace is bottom loaded and has a door seal carried by the base so that the seal is not exposed to the direct heat from the muffle when the door is opened.

Abstract: A furnace for isostatic hot pressing includes a furnace compartment contained within a pressure chamber, the compartment being surrounded by a insulating sheath, comprising a cup-shaped insulating portion. Such portion comprises a supporting tube of graphite surrounded by a plurality of layers of carbon or of graphite fibers. Convection-preventing layers of graphite foils are disposed between the layers and between the innermost layer and the tube. The layers are maintained pressured against the tube and against one another by a plurality of surrounding graphite strands. A plurality of cover discs of foamed graphite having graphite foils on one side thereof are seated against upper ends of the layers and of the tube, the foils on the discs extending upwardly to lie against the peripheral end walls of the discs.

Abstract: The present invention is a method and apparatus for heat treating at least one work item, such as a coil, having an axial passage and being axially stacked on a base support means disposed within a cover means which is located on the base support means. The base support can be on the floor of a furnace and with the chamber of the furnace. A means to force the atmosphere such as an axial fan is located in the base. The atmosphere is forced axially from the base, up through an axial path including the axial passage of the at least one coil, through a top space between the top of the stack of coils and the top of the cover means, down through the annular space between the outside of the coils and the inside of the cover means, and back to the axial path through a base space beneath the at least one coil, communicating from the annular space to the axial path.

Abstract: A high-pressure furnace having a pressure chamber which includes an insulating mantle which encloses the furnace space, the insulating mantle itself including an inner tube which has at least one layer of felt-like, fibrous insulating material mounted on the side which faces the furnace space.

Abstract: The invention is a simple and reliable mechanical arrangement for automatically positioning a thermocouple-carrying rod in a vacuum-furnace assembly of the kind including a casing, a furnace mounted in the casing, and a charge-containing crucible mounted in the furnace for vertical movement between a lower (loading) position and a raised (charge-melting) position. In a preferred embodiment, a welded-diaphragm metal bellows is mounted above the furnace, the upper end of the bellows being fixed against movement and the lower end of the bellows being affixed to support means for a thermocouple-carrying rod which is vertically oriented and extends freely through the furnace lid toward the mouth of the crucible. The support means and rod are mounted for relative vertical movement.

Abstract: An apparatus or system for cooling the interior of an autoclave furnace vessel after it has been pressurized with a gas and heated. The system comprises a heat conducting conduit opening at one end to the furnace interior and at the other end to a shut-off valve exterior to the vessel. Intermediate the two ends of the conduit is a coil portion comprising a heat exchanger positioned at a location in the furnace where hot vessel gases may be forced through or past the coil. Furnace gases are forced into the conduit and therefore through the coiled portion where they are heated prior to being exhausted. According to a preferred embodiment of this invention, there is a Joule-Thomson valve before the coiled portion of the conduit to reduce the temperature of the exhausting gases prior to arriving at the coiled portion.

Abstract: A device for gradient heating of a wire includes a vacuum chamber with a thermostatically regulated base and a means for producing a temperature gradient arranged thereinside. The means for producing a temperature gradient is designed in the form of a metallic cylinder with one end thereof having an electric heater and the other end being attached to the thermostatically regulated base of the vacuum chamber, serving as a cooler. The surface of the metallic cylinder is furnished with transverse grooves intended for locating therein a wire being heated and interconnected by a longitudinal groove intended for passing the wire from one transverse groove into the other.

Abstract: An apparatus or system for cooling the interior of an autoclave furnace vessel after it has been pressurized with a gas and heated. The system comprises a heat conducting conduit opening at one end to the furnace interior and at the other end to a shut-off valve exterior to the vessel. Intermediate the two ends of the conduit is a coil portion comprising a heat exchanger positioned at a location in the furnace where hot vessel gases may be forced through or past the coil. Furnace gases are forced into the conduit and therefore through the coiled portion where they are heated prior to being exhausted. According to a preferred embodiment of this invention, there is a Joule-Thomson valve before the coiled portion of the conduit to reduce the temperature of the exhausting gases prior to arriving at the coiled portion.

Abstract: An apparatus for treating a workpiece at elevated temperatures and pressures comprising an elongate cylindrical pressure vessel. Within the pressure vessel a hearth sits upon a pedestal. Surrounding the pedestal and the workspace immediately thereabove is an insulated furnace enclosure. A cavity near the base of the pedestal defines an impeller chamber. An impeller is positioned in the chamber and has a downwardly extending drive shaft. The impeller circulates the pressurized atmosphere. A remotely actuated gate directs the circulating atmosphere to either circulate totally within the furnace enclosure or partially within the furnace enclosure and partially along the interior wall of the pressure vessel.

Abstract: The high pressure furnace comprises a cylindrical pressure vessel with front and rear pressure closures. An electrical heating element is supported within the interior of the pressure furnace. The front closure supports a relatively thin-walled inner container opening only to an aperture in the front closure. A small closure plugs the aperture. A reaction frame secures the various closures. Blanket gases are introduced into the furnace chamber and process gases into the process chamber defined by the interior of the inner container. Means are provided for minimizing the pressure difference across the inner container to enable it to maintain its original shape.

Abstract: A method of producing a high vacuum in a container which has limiting walls hich define a reaction chamber which is adapted to be evacuated for vacuum processing purposes, and in which gases are sorbed during vacuum operation and the gases are removed subsequently by increasing the temperature of the walls and evacuating the chamber at the same time includes heating the reaction chamber, sensing the underpressure in the reaction chamber and controlling the heating of the chamber in accordance with the sensed pressure in a manner such that the underpressure remains within a preselected upper and lower limit value until a predetermined temperature of the walls is attained.