Abstract: The invention comprises an electric heating assembly having improved heat transfer, the heater comprised of a receptacle for containing amalgam heat transfer media. An amalgam heat transfer media is provided in the receptacle for purposes of heat transfer. An electric heating element is located in the amalgam. When the amalgam reaches a solidified condition, a receptacle or mold is not required for the electric heating assembly.

Abstract: An apparatus for melting and dispensing thermoplastic materials such as thermoplastic adhesives referred to as “hot melt” adhesives. More specifically, a one-piece melter tank is suspended from the top of a chassis which also serves as the housing for the entire assembly of the melting and dispensing apparatus.

Abstract: The invention comprises an electric heating assembly having improved heat transfer, the heater comprised of a receptacle for containing amalgam heat transfer media. An amalgam heat transfer media is provided in the receptacle for purposes of heat transfer. An electric heating element is located in the amalgam. When the amalgam reaches a solidified condition, a receptacle or mold is not required for the electric heating assembly.

Abstract: An externally heated hot-runner nozzle for producing injection molded parts has a resistance wire which is composed of an inner electric heating conductor, a ceramic insulating intermediate layer and an outer metal sheath and comprises two end portions to which a heating voltage can be applied, as well as an intermediate section which in the form of a heating coil is assigned to the circumference of the hot-runner nozzle. The resistance wire is characterized in that the two end portions having an outer diameter of 1.5 mm to 2.5 mm are dimensioned to be larger than the intermediate section having an outer diameter of 1.0 mm to 1.8 mm.

Abstract: An electrical resistance heater for use in a crystal puller used for growing monocrystalline ingots according to the Czochralski method comprises a heating element sized and shaped for placement in the housing of the crystal puller for radiating heat within the housing. The heating element has heating segments arranged in a generally side-by-side relationship and electrically connected together. Each heating segment comprises a web and a flange projecting outwardly from the web in non-coplanar relationship therewith. This reduces the cross-sectional area of the heating segment for increasing the electrical resistance and power output of the heater while providing desired structural rigidity.

Abstract: A wax applicator for depilation has one of its side walls forming a removable cover having transparent or partially transparent properties. The body of the applicator presents a U-shaped outline designed to permit insertion of a wax cartridge. The cover has sensors and/or windows for viewing the characteristics of the cartridge wax. The body of the application has a removable top forming a protective cover over the wax cartridge to shelter it thermally.

Abstract: A heater for the injection nozzle of a die casting machine includes a mounting block which is clamped to the nozzle and has a cavity for receiving an off-the-shelf electric cartridge heater. The mounting block includes a casing formed from a high strength material such as steel and a quantity of a second material having a high thermal conductivity such as copper encased in the casing. A hole sized to receive the injection nozzle is formed through the block and passes through the second material so that the second material forms a portion of the inner surface of the hole. The heater cavity extends into the block along an axis generally perpendicular to the hole such that the second material forms a portion of the inner surface of the hole. The quantity of second material connects the two holes and forms a heat conductive path between the heater receiving hole and the nozzle receiving hole.

Abstract: A low profile heater for plastic injection molding equipment nozzles utilizes forces provided to the axially ends of a tube portion to radially compress the tube portion onto a coiled heater element thereby compressing the heater element radially inward for optimal heat conduction between said heater element and the nozzle onto which the heater is attached. Further embodiments uses a base sleeve onto which the coiled heater element is placed to engage the nozzle. The base sleeve may utilize a tapered threaded portion with slits in the sleeve to allow tightening of a ring portion to radially compress the sleeve base onto the nozzle.

Abstract: An electrical resistance heater for use in a crystal puller used for growing monocrystalline silicon ingots according to the Czochralski method comprises a heating element sized and shaped for disposition in the housing of the crystal puller around the crucible for applying heat to the crucible and silicon therein. The heating element includes heating segments connected together in an electric circuit. The segments have upper and lower sections and are arranged relative to each other so that when disposed around the crucible containing molten silicon the upper sections are disposed generally above a horizontal plane including the surface of the molten silicon and the lower sections are disposed generally below the horizontal plane. The upper sections are constructed to generate more heating power than the lower sections thereby to reduce a temperature gradient between the molten silicon at its surface and the ingot just above the surface of the molten silicon.

Abstract: An improved crucible for containing a body of molten aluminum and maintaining the molten aluminum at a predetermined temperature for transportation, the crucible comprised of a bottom and sides joined together to contain the molten aluminum and a liner comprised of a refractory substantially inert to the molten aluminum. A series of heating element receptacles are provided in the liner, the receptacles are lined with a ceramic tube fabricated from a material selected from the group consisting of mullite, boron nitride, silicon nitride, silicon carbide, and silicon aluminum oxynitride, zirconia, stabilized zirconia and mixtures thereof. An electric heating element is provided in the ceramic tube for transferring heat to the body of aluminum.

Abstract: Hot runner injection molding systems with externally heated injection runner nozzles for such systems. The heater is preferably a tubular heater with the resistive element applied to the exterior surface by fine film printing. The heater is adapted to externally heat a hot runner injection mold runner nozzle.

Abstract: An apparatus for melting and dispensing thermoplastic materials such as thermoplastic adhesives referred to as "hot melt" adhesives. More specifically this invention relates to a one piece melter tank which is suspended from the top of a chassis which also serves as the housing for the entire assembly of the melting and dispensing apparatus.

Abstract: A hair removal wax device comprising at least one tank (9) linked to a heating means (11) and a detachable instrument, independent from the tank (9), designed for sampling from the tank (9) a quantity of molten wax, with a means (12) for transferring of a quantity of hair removal wax from the tank (9) to the detachable instrument, where the detachable instrument is a ductile vessel (1) whose inside volume is variable.

Abstract: An apparatus for liquifying and supplying thermoplastic material including a melting hopper having a plurality of separately controlled heating zones. The hopper is formed of thin, rolled metal having a relatively low heat conductivity, such as carbon steel. Heaters are located along the length of the hopper and are separately controlled by way of thermostats or temperature sensors, such that the heat applied in a nonuniform manner to the thermoplastic material in the hopper during various stages of the melting and dispensing process.

Abstract: The glue gun system includes a gun having a barrel. A cartridge can be removably placed in the barrel. The cartridge has an open central passage to accept a glue stick and a tip to dispense the glue. Once received into the barrel the cartridge is heated, melting the glue therein. Additional cartridges can be maintained in a heated state by a heating stand. Thus, after one glue stick is used, a second can be immediately installed and used. An insulated tab allows for the easy handling of the cartridges.

Abstract: A reforming reactor is provided with a catalyst and a heating resistor. The heating resistor is embedded in a catalyst. A reforming reactor can start rapidly with high thermal efficiency and which is excellent in recovery of hydrogen.

Abstract: A boiler for an espresso coffee maker comprises a metallic body (12) comprising a cover (15) with a peripheral flange (16) and a cup (18) connected in sealed fashion to the cover (15). A downwardly-extending water supply tube (26) extends through the cover. An electric heating resistance (24) is provided. A vertical water outlet conduit (32) opens through the bottom of the cup (18), and a valve (39) is disposed in the conduit (32) and opens only when a certain pressure threshold is reached. The peripheral flange (16) of the cover (15) of the body (12) is shaped as a gutter (22) in which is positioned in intimate thermal connection the electric heating resistance (24).

Abstract: A method of making an integral heated nozzle using a terminal locating and sealing key. A spiral portion of an electrical heating element is press fitted into a spiral groove in the cylindrical outer surface of an elongated inner portion. The remaining outwardly extending terminal portions of the heating element are inserted through two holes in the key and the key is pushed inwardly to a position against the inner portion. The key has a pin portion which is received in a matching hole in the inner portion to exactly determine the length of the spiral portion of the heating element and accurately locates the terminal portion of the heating element. An outer collar portion having a slot in which the key is received is then mounted in place around the rear end of the inner portion. A thermosetting ceramic sealant is applied in the space between the inner and outer collar portions then heated to integrally joint them together.

Abstract: A hopper-type dispensing unit for receiving and melting a slug of thermoplastic material, such as hot melt adhesive. In a first embodiment a plurality of container supports formed of a material, such as steel, having a low heat conductivity extend inwardly from inner walls of the unit and radially inward of the opening in the inverted container to obstruct the path of the adhesive slug and cause a smooth, controlled descent. The steel supports are vertical members which extend upwardly from a melting grid of the unit to a point which allows a significant portion of the adhesive slug to remain in the apparatus when the container is empty. A plurality of heating fins are also provided about the inner periphery of the hopper and are generally disposed between the steel supports in the first embodiment. In a second embodiment the container supports are eliminated and the container is supported in another manner, leaving the fins as both slug descent control elements and supplemental heating elements.

Abstract: The invention defines an apparatus for controlling oxygen content in Czochralski silicon crystal pullers in which silicon is melted in a quartz crucible. The apparatus includes a susceptor 10, a quartz crucible 12 in said susceptor, a cable 16 for lowering a seed crystal 14 into silicon melted in said crucible, and a combination spiral heater/magnetic coil 25 for heating and melting silicon in said crucible, and for producing a magnetic field around the crucible.

Abstract: An electrically heated metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments.

Abstract: Apparatus for the simultaneous production of preforms consisting of polyethylene terephthalate (PET) fed and distributed to a plurality of cavities. In order to reduce the occurrence of acetaldehyde formation in a cavity, for example, a heated distributor block used in the production of preforms of the PET material, the material flowing through a channel is subjected to additional turbulence. To this end, an element, preferably of metal, is installed in the channels, such element being provided with sets of radial spokes which are azimuthally offset in relation to each other in the axial direction. Besides inducing turbulence, such spokes act as homogenizing elements serving to diffuse heat over the cross section of the flowing process material.

Abstract: An interchangeable module for supporting a receptacle into which a molten sample, prepared by a fluxer, can be poured for analysis. One module can support a resistively heated casting dish into which a molten sample can be poured and cooled to form a solid sample for instrumental analysis. This module includes an insulator having a depression for receipt of a casting dish. A heating coil is positioned below the recession. A cooling gas conduit extends through the insulator support. The insulator is supported on a frame. The frame is supported on a back plate.

Abstract: A method of making an injection molding nozzle having an electrical heating element wound in a channel. The heating element has two terminal wires which extend radially outward parallel to each other from either a common end portion or two separate end portions of the heating element. After the heating element is wound in the spiral channel in the nozzle body, forward and rear collar portions are mounted around the nozzle body to form a radial slot or opening between them through which the end portion or portions of the heating element project. A stud portion is mounted to extend radially outward from the slot with a single bore or two parallel bores through which the end portion or portions extend. These components are then brazed together in a vacuum furnace to form a strong integral structure with the end portion or portions of the heating element secured in place. In one embodiment, a spacer portion having two parallel bores is mounted with ceramic paste to the stud portion.

Abstract: A flexible vertebra-like heating element useful in a hot runner housing of an injection molding machine including method of manufacture and method of installation.

Abstract: In a hot runner system for injection molding, a runner block (10) has a bore (14) in a casing (12) for facewise insertion of a heatable cartridge (16) comprising a core member (30) with an inside runner (34). A flow tube (32) having flow passages (35, 36) at its face ends and/or at its periphery carries an electrically insulated (39) heating coil (38) overcast with a thermoconductive mass (V) containing aluminium. Abutting members (18) seal the runner block (10) axially. Spaced radial supports (40, 49, 69) project over the outer diameter (D) of the core member (30), hollows or recesses (41, 44) serving for minimum heat transfer at the bearing area. An outer sleeve body (20) of the flow tube (32) may have sections (21 to 24) with a recessed central portion (46) sealingly engaging a collar-type support (40). Narrow peripheral ribs (42, 50) axially separate ring pockets (41) and outer compartments or spaces (52).

Abstract: A system for safely disposing of pathogenic waste materials. The waste material is disposed in a chamber and heated by forced hot air to temperatures above approximately 450.degree. F. to destroy harmful bacteria within several minutes. The high temperatures melt plastic waste materials. The harmless waste is cooled providing a solid block in which syringes and other sharp items are generally encased. The temperature within the chamber is continuously sensed and the operation of the apparatus is microprocessor controlled to adjust the process time in accordance with the load size. The microprocessor further stores the sensed temperature to provide verification that the waste has been exposed to sufficient temperatures and for a sufficient time to render such waste harmless.

Abstract: A compact injection molding melt distribution manifold. The manifold has integral or monolithic inlet and main portions and both portions have a common electrical heating element. A melt passage extends through the manifold from a common inlet in the inlet portion and branches in the main portion to a number of spaced outlets leading to different gates.

Abstract: A sprue bushing with an integral casing construction which as improved heat transfer characteristics and a method of making the same are described. A cylindrical bushing body having a first, preselected uniform diameter has a cavity formed therein which axially extends within the bushing body for a predetermined length. A bushing inner core which is integral with the bushing casing is formed in the cavity and extends between the two ends of the bushing body. One or more heating elements in the form of coil heaters may be inserted into the bushing body cavity and a thermally conductive material is deposited into the cavity to fill the remainder of the cavity. When filled, the bushing body is heated to melt the thermally conductive material around the heating element(s) to form a unified heater assembly in the annular cavity. A melt runner passage is then drilled through the inner core.

Abstract: A sprue bushing which eliminates melt leakage and a method of making the same are described. A cylindrical bushing body having a first, preselected uniform diameter has an annular cavity formed therein which axially extends within the bushing body for a predetermined length and which separates the bushing inner core from the bushing body. A heating element in the form of a ceramic insulator sleeve is inserted into the annular cavity and a particulate refractory material is deposited into the annular cavity to fill the remainder of the annular cavity. When filled, the bushing body is swaged down to a second preselected uniform diameter to compact the powdered refractory together with the preformed sleeve to form a solid heating element. A runner passage is then drilled through the inner core so that the inner core is integral with the bushing casing.

Abstract: A unitary integral electrically heated nozzle device for plastic molding or die casting equipment which has a novel casing integral with a heater core, which is insulated to prevent conduction of electricity and loss of thermal transmission to the casing, the electrical insulation being compacted within the casing and around the heater core and the assembly being sealed and swaged into a unitary form, said device being structured to heat the area of a gate or passage for delivery of molten material into a forming cavity. The nozzle device may be shaped, and the nozzle systems include such nozzle devices in the gate channels for delivering molten material to the forming cavity.

Abstract: This invention relates to an improved injection molding nozzle and a method of making it. The nozzle has an electric heating element integrally vacuum cast in copper in spiral channels set in the outer surface of the tool steel nozzle body. The heating element has a cold terminal at one end which projects out through a hole in a head plate which is rotatable prior to casting to ensure the nozzle has a consistent length of heating element cast in. A sleeve is located over the spiral channel prior to casting to ensure the heating element in the channel is covered with a minimum depth of copper to dissipate the heat from the heating element. The spiral channel can be cut with a varying pitch according to a predetermined profile to provide more heat where there is more heat loss.

Abstract: A plastification cylinder of an injection molding machine includes an outside cylinder and an inside cylinder, the inside cylinder including heating elements and temperature sensors therearound and defining a screw antechamber at one end thereof, the outside cylinder being shaped so that the end thereof which surrounds the end of the inside cylinder that defines the screw antechamber is in a pressure fit contact with the inside cylinder while the other end of the outside cylinder is spaced away from the corresponding end of the inside cylinder, thereby providing an annular chamber therebetween. Connecting elements extending through the outside cylinder can be used to cause a fluid heating or cooling medium to flow through the annular chamber.

Abstract: A molecular beam source suppresses a temperature fall at the opening of a crucible, to make a temperature distribution within the crucible uniform and to prevent the phenomenon of bumping of a source substance, whereby the quality of an evaporated film can be enhanced. The source includes a heater disposed around the crucible which is formed of straight parts and U-shaped end parts continuously repeated at equal intervals. The straight parts are arranged so as to extend in a vertical direction of the crucible and the U-shaped end parts are bent outwards at outer-peripheral positions of the opening of the crucible.

Abstract: A heater has two, hollow, half-cylindrical heat guides fastened to each other at one side by an articulated connector and at the other side by a bolted joint. Internal surfaces of the heat guides represent the shape of the object being heated. On external surfaces of the heat guides, there are a series of, preferably flat splines. Lamellar heating elements are fastened to the splines. Mutual adherence surfaces of the heating elements and splines are shaped according to geometrical patterns, the appropriate selection of which changes the thermal characteristics of the heater over a wide range. The heater may be supplied from single- or three-phase mains. The heater is applicable especially for heating the cylinders, nozzles and tools of injection moulding and extrusion machines.

Abstract: At least one of the heated side walls of the oil container of a deep fryer is unbent to have planar interior and exterior surfaces. A sheet metal channel member, secured to the exterior surface of that side wall by flanges that flatwise overlie it, defines a tubular pocket which is open at one end. An electric heating element is embedded in an elongated heating body of electrically insulating material that is lengthwise slidably received in the tubular pocket with a close fit to be readily replaceable. Heat that the heating body radiates outwardly away from the wall is imparted to the channel member, the flanges of which transfer such heat to the wall in zones adjacent to the heating body.

Abstract: This heating cylinder device for a molding machine includes a cylinder member along the axial direction of which and within which are defined several heating zones for material to be molded, each of the heating zones being provided with a heater, wherein the heating capacities and the thermal conductivities to the exterior of the heating zones are suitably arranged so as to correspond to the temperatures and operational performances required from the heating zones. Each of the heaters may optionally surround the portion of the cylinder member defining its heating zone.

Abstract: A device for the manufacture of molded parts from molding materials, includes a molding tool being completely closed, having a molding cavity formed therein and being divisible, a heating device having two heating plates disposed on top of each other and fastened to the molding tool, the heating plates being in mutual contact along respective contact surfaces thereof, at least one of the contact surfaces having slots formed therein, and tubular electrical heating elements with metal cladding press-fitted in the slots.

Abstract: The heating element has a heat conductor in the form of a metal tube. The molten plastic is conveyed to the tube through an inflow aperture. The end of the tube that is remote from the inflow aperture is shaped into a point and has flowthrough apertures. The tube is welded in the vicinity of the point to an outer jacket made out of a material with a low specific electric resistance. Outside the welding point, there is a layer of insulation between the tube and the outer jacket. The layer is between 0.1 and 0.5 mm thick and can be made out of ceramic. The electric energy supplied to the tube is so low that the molten plastic is not subjected to thermal overload in the vicinity of the point.

Abstract: This invention relates to hot tip bushing means for a synthetic resin injection molding machine, which can reduce the pressure loss at the injection molding time and determine the position of a heating tip easily and accurately. To attain this purpose, a straight resin flow passage is formed axially in a cylindrical body of the hot tip bushing means and the fused resin passing through the straight resin flow passage is heated by an outer heater. Further, a cylindrical body of the hot tip bushing means which is near the heating tip is fit to a mold sprue, thereby the position of the heating tip is determined easily and accurately.

Abstract: The invention provides an apparatus and method for heating a vessel having a vessel bottom and at least one vessel side wall. The invention includes a furnace housing which is adapted to contain the vessel and which has a housing bottom and at least one housing side wall. A heater mechanism, located at the housing bottom and at the housing side wall, heats the vessel and is adapted to contact selected portions of the vessel bottom and vessel side wall. Thermal insulation is disposed about the housing for reducing heat loss therefrom, and an extendable temperature sensor is adapted to contact the vessel and monitor the temperature thereof.

Abstract: An apparatus for melting and dispensing thermoplastic material comprising a melter tank, a pump contained within the melter tank, a dispenser, and a manifold block mounted on the bottom of the melter tank. Thermoplastic material melted in the tank flows from the melter tank through the pump through the manifold block to the dispenser. The melter tank comprises a novel electrical resistance heating element cast into the bottom wall of the tank. The heating element is asymetrically shaped within the bottom wall of the melter tank and is so configured that the length of the heater element within any portion of the bottom wall is proportional to the mass of material, including melter tank, manifold block, pump, and thermoplastic material to be heated by the given length of heater element within that portion. Additionally, the tank side walls are generally triangular in cross section with the thicker part of the triangular shaped side walls located adjacent the bottom of the tank.

Abstract: An evaporation heater having a wire wound into a coil and a support wire which extends from one arm of the wire outside of the coil, in spaced proximity therewith, to a central position within the coil but out of electric contact therewith is disclosed. An annular pellet of evaporant material is positioned over the wire support arm within the heater coil but out of contact therewith.The atmosphere around the heater coil and pellet is substantially evacuated and current is directed through such coil to apply radiant heat to the pellet to evaporate same.Because the heater coil is in spaced proximity with the pellet of evaporant material and not in contact therewith, chemical reaction therebetween or erosion is avoided, and a durable evaporation heater of uncomplex construction is provided.

Abstract: This invention relates to an improved connector assembly for an electrically heated injection molding sprue bushing and a method of making the same. The sprue bushing has a helical portion of the heating element extending around a central core portion which conveys pressurized melt from a molding machine to a cavity in the mold. It is formed by filling the space between the stainless steel core portion and a stainless steel outer sleeve by a highly conductive copper alloy. The heating element has a lead portion which extends out through an aperture. The aperture provides a seat which receives two split washers with central openings therethrough for the lead portion. The washers are each formed of two half washers which are oriented so that the divisions therebetween are not aligned. A connector sleeve is inserted over the projecting lead portion with a flared end which is received in the aperture against the washers. The washers and connector sleeve are brazed in position in a vacuum furnace.

Abstract: This invention relates to an improved method of making a sprue bushing for injection molding and the improved sprue bushing made thereby. The runner passage extends through a corrosion resistant inner core portion with an outer surface around which a helical electrical heating element is located. A stainless steel outer sleeve extends between an enlarged front portion which provides the opening to the gate and an enlarged back collar portion which provides for connection to the heating element leads. The space around the heating element is filled by a highly conductive material such as a beryllium copper alloy in a vacuum furnace which causes the beryllium copper to fuse with the adjacent materials. This improves the transfer of heat from the heating element to the melt and the outer sleeve substantially reduces the costly machining required to produce the finished product as well as provides additional strength.

Abstract: This invention relates to an improved method of making a sprue bushing for injection molding and the improved sprue bushing made thereby. The runner passage extends through a corrosion resistant inner core portion with an outer surface around which a helical electrical heating element is located. A stainless steel outer sleeve extends between an enlarged front portion which provides the opening to the gate and an enlarged back collar portion which provides for connection to the heating element leads. The space around the heating element is filled by a highly conductive material such as a beryllium copper alloy in a vacuum furnace which causes the beryllium copper to fuse with the adjacent materials. This improves the transfer of heat from the heating element to the melt and the outer sleeve substantially reduces the costly machining required to produce the finished product as well as provides additional strength.

Abstract: An apparatus for liquefying meltable material comprises a container adapted to be filled with the material to be liquefied. The container has a heavy bottom wall formed with closely adjacent perforations which taper in downward direction. The sum of the open cross-section of the perforations at the upper face of the bottom wall is only slightly smaller than the total area of the latter, whereas the sum of the smallest cross-sections of the perforations is only a small fraction of the total area of the bottom face of the bottom wall. The bottom wall is heated by electrical heating elements located in ribs separating the perforations from each other to a temperature to liquefy the material passing from the container into the perforations and the liquefied material flows in a collecting trough arranged below the container and separated by a heat insulating layer therefrom.

Abstract: A plastic injection molding system having a temperature controlled electric heater element.The heater element is formed by disposing a pair of heater wires and a pair of thermocouple wires and a powdered mineral material in a metal sheath which is subjected to repeated drawing and annealing operations and is then cut to a desired length after which at one end, the heater wires are welded together and the thermocouple wires are welded to the sheath and the sheath is welded to form a closed end wall. At the opposite end, the heater and thermocouple wires are connected through connection means and connection wires to a current supply and a temperature sensing circuit. The sheath is in the form of a rightly wound helical coil structure and is installed in direct heat transfer engagement on a cylindrical surface of a metal part which has an axially extending plastic flow passage therein.

Abstract: A flask heater assembly for spherical bodied, boiling flasks in which a block is hollowed to receive the flask body and a ribbon of electrical resistance heated, flexible metal is folded into an elongated band and bent and fitted into the hollow to conform with the shape of the flask. A reduced voltage current is supplied to the ends of the ribbon to produce a temperature on the order of 400.degree. C., i.e., well below the glow temperature of the metal.

Abstract: The effusion cell for molecular beam epitaxy apparatus consists of a pyrolytic BN cylindrical crucible surrounded by a heating coil. The position of the heating coil is maintained by a plurality of ceramic rods extending parallel to the cylinder axis with notches along their length for engaging the heating coil. The ceramic rods are secured by a retaining ring near the front of the crucible and an apertured disk near the back of the crucible. The entire assembly is surrounded by a foil heat shield.