US3926415A - Method and apparatus for carbonizing and degassing workpieces - Google Patents

Method and apparatus for carbonizing and degassing workpieces Download PDF

Info

Publication number
US3926415A
US3926415A US435677A US43567774A US3926415A US 3926415 A US3926415 A US 3926415A US 435677 A US435677 A US 435677A US 43567774 A US43567774 A US 43567774A US 3926415 A US3926415 A US 3926415A
Authority
US
United States
Prior art keywords
chamber
carriage
workpiece
top wall
pedestal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US435677A
Other languages
English (en)
Inventor
William W Konas
Paul L Day
Roger R Budzinski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Park Ohio Holdings Corp
Original Assignee
Park Ohio Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Park Ohio Industries Inc filed Critical Park Ohio Industries Inc
Priority to US435677A priority Critical patent/US3926415A/en
Priority to CA217,031A priority patent/CA1020344A/fr
Application granted granted Critical
Publication of US3926415A publication Critical patent/US3926415A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/003—Apparatus, e.g. furnaces

Definitions

  • Workpiece input and output chambers are disposed on top of the enclosure, and a series of workpiece heating and cooling chambers are provided on top of the enclosure between the input and output chambers. All of the chambers open into the enclosure, and the input and output chambers have closures spaced from the transportation chamber to facilitate the insertion and removal of workpieces from the enclosure free of the ingress of ambient air into the furnace. workpieces to be treated are inserted into the furnace by way of the inlet chamber, sequenced through the heating and cooling chambers and removed from the furnace through the output chamber. An auxiliary cooling chamber is provided for a dummy workpiece which is introduced into a heating chamber following a heating operation to facilitate cooling thereof.
  • the present invention relates to the art of heat treating workpieces and, more particularly, to a method and apparatus including an inductively heated furnace operable to sequentially receive, heat, cool and discharge workpieces.
  • the present invention finds particular utility in conjunction with the heat treating of workpieces such as might be defined by a green billet of powdered metal which must be carbonized and degassed and then sintered. Accordingly, the invention will be disclosed and described with particular reference to such use. It will be appreciated, however, that the method and apparatus have utility in conjunction with other workpiece heat treating operations.
  • Method and apparatus have been provided heretofore for carbonizing and degassing green workpieces and then sintering the workpieces.
  • such operations include sequentially heating the workpieces to a temperature to drive off gases therein, heating the degassed workpieces to a sintering temperature and then cooling the workpieces.
  • both the heating and cooling operations generally take place in a gaseous atmosphere devoid of ambient air. More particularly, a workpiece to be treated is introduced into an enclosed space in which the desired controlled atmosphere is maintained.
  • the workpiece is then conveyed sequentially to one or more heating fumaces associated with the enclosed space and then to a cooling chamber associated with the enclosed space so that the workpiece is carbonized and degassed, sintered, and cooled prior to removal from the enclosed space and the consequent exposure of the workpiece to ambient air.
  • Methods and apparatus for achieving heat treatment in the foregoing manner should provide a high production rate with regard to the output of workpieces per hour for a given line of operation.
  • structural arrangements provided to achieve the transporting of workpieces between the working stations of the apparatus and the displacement of workpieces into the heating and cooling chambers should be efficient in operation and economical from the standpoint of production and maintenance costs.
  • arrangements for introducing and removing workpieces from the apparatus without materially affecting the controlled atmosphere within the enclosure should be structurally simple and economical.
  • the workpiece heating and cooling times are generally preset, whereby the time required to achieve the feeding, conveying, displacing and discharging functions is directly related to production rate. Accordingly, it becomes desirable to minimize the time required to achieve the latter functions.
  • a cold workpiece introduced into a cabonizing and degassing furnace chamber must be heated at a predetermined heat rate in elevating the temperature thereof to the desired level. Following the heating of one workpiece the furnace chamber must be sufficiently cooled before the introduction of another workpiece thereinto to assure that the heat rate with respect to the second workpiece is not higher than acceptable. Accordingly, the furnace is shut down or de-energized following the removal of the first workpiece and is allowed to cool sufficiently prior to introduction of the second workpiece thereinto. It will be appreciated that production rate can be affected by the time required for the furnace chamber to cool if such time exceeds the normal time required to achieve other conveying and displacing functions prior to insertion of the second workpiece into the chamber. Therefore, it becomes desirable to minimize the time required to cool the furnace chamber to the temperature necessary to avoid an undesirably high initial heat rate.
  • heat treating apparatus which is structurally compact and in which the components of the apparatus are structurally interrelated to enable economical use of floor space in a plant or the like.
  • input and discharge of workpieces from the apparatus is in a vertical direction, and the heating and cooling chambers for the workpieces are disposed above the path of movement thereof between the input and output ends of the apparatus.
  • the workpieces are displaced upwardly into the heating and cooling chambers from a conveying mechanism which supports the workpieces for movement between the input and discharge ends of the apparatus.
  • the vertical relationship between the components of the apparatus minimizes the floor space requirement for the apparatus laterally with respect to the path of movement of workpieces therethrough.
  • the vertical input and discharge of workpieces and the vertical displacement thereof into the heating and cooling chambers is achieved by corresponding elevating mechanisms disposed beneath the conveying apparatus at spaced locations corresponding to the input, heating, cooling and output stations.
  • the elevating mechanisms reciprocate along corresponding linear paths to displace a workpiece relative to the conveying device and workpiece chambers at the input, heating, cooling and discharge stations.
  • the elevating mechanisms advantageously provide for the displacement operation to be efficient and provide for desired alignment between a workpiece and a chamber into which it is displaced.
  • the displacement mechanisms minimize transfer time of a workpiece to and from a chamber.
  • the conveying device is adapted to support a pedestal member which is displaceable from the conveying device together with a workpiece supported by the pedestal.
  • the pedestal is elevated from the conveying device to move the workpiece into a chamber, and the pedestal is adapted to be held in place with respect to the chamber and to seal the entrance through which the workpiece is inserted.
  • the input and discharge stations of the apparatus are provided with air lock chambers which permit a workpiece to be introduced and removed from the apparatus free of any undesirable effect on a controlled atmosphere within the apparatus.
  • the pedestal member is operable at the input and output stations to seal the corresponding chambers to assure against the ingress of ambient air into the apparatus during the input and discharge operations.
  • the apparatus is provided with an auxiliary cooling chamber adapted to receive a dummy workpiece which is cooled while in the auxiliary chamber.
  • the workpiece heating chamber or chambers are inductively heated and, following removal of a heated workpiece from a heating chamber, the inductor for the chamber is de-energized so that the chamber can cool prior to the transfer of a green workpiece thereinto.
  • the dummy workpiece is transferred from the auxiliary cooling chamber into the de-energized heating chamber to assure sufficient cooling of the chamber.
  • the auxiliary cooling assures against a higher initial heat rate than desired for the green workpiece when the latter is introduced into the heating chamber.
  • the auxiliary cooling minimizes the cooling time and avoids the possibility of a time delay resulting from natural cooling and which would result in a decrease in production rate.
  • An outstanding object of the present invention is the provision of apparatus for sequentially heating and cooling workpieces transferred therethrough and by which a high production rate is achieved and transfer of workpieces through the apparatus and displacement of the workpieces relative to heating and cooling chambers of the apparatus is highly efficient.
  • Another object is the provision of apparatus of the foregoing character which. is economical to produce and operate and occupies a minimum amount of floor space in a direction laterally with respect to movement of workpieces therethrough.
  • Still another object is the provision of apparatus of the foregoing character in which transfer of workpieces is along a horizontal path, and workpiece input, displacement and discharge operations are along vertical paths above the horizontal path, thus to minimize dimensions of the apparatus laterally of the horizontal path.
  • a further object is the provision of apparatus of the foregoing character in which the workpiece conveying device and the workpiece input, displacing and discharging devices are of simple construction and are structurally cooperable to achieve the workpiece input, displacing and discharging operations efficiently and in a minimum amount of time.
  • Still another object is the provision of apparatus of the foregoing character in which the vertically reciprocable displacing devices are operable to assure displacement of a workpiece and a support pedestal therefor into a chamber at the heating, cooling and discharge stations in properly aligned relationship with respect to the chamber.
  • Still a further object is the provision of apparatus of the foregoing character in which the support pedestal for a workpiece is cooperable with the chambers at the input, heating, cooling and discharge stations to seal the interiors of the chambers.
  • Yet another object is the provision of a method of heat treating workpieces by sequentially transferring a workpiece into a heating chamber which is inductively heated, transferring the heated workpiece to a cooling chamber, de-energizing the induction heating device, and artifically cooling the heating chamber prior to the introduction of another workpiece thereinto.
  • Another object is the provision of a method of the foregoing character in which artificial cooling is achieved by transferring a dummy workpiece from a corresponding cooling chamber into the heating chamber following removal of the heated we'rkpi'ece therefrom.
  • FIG. 1 is a schematic representation of the components of carbonizing and degassing apparatus in accordance withthe present invention
  • FIG. 2 is a side elevational view showing a structural embodiment of the apparatus schematically illustrated in FIG. 1;
  • FIG. 3 is a detailed side elevation view, partially in section, of the workpiece input end of the apparatus illustrated in FIG. 2;
  • FIG. 4 is a sectional elevation view of the apparatus taken along line 4-4 in FIG. 2;
  • FIG. 5 is a sectional elevation view of the apparatus taken along line 5-5 in FIG. 2;
  • FIG. 6 is a sectional elevation view of the apparatus taken along line 66 in FIG. 2;
  • FIG. 7 is a sectional elevation view of the apparatus taken along line 7-7 in FIG. 2.
  • FIG. 1 of the drawing apparatus for carbonizing and degassing workpieces W is schematicallyillustrated in FIG. 1 of the drawing.
  • the apparatus includes a gas tight enclosure 10 having closed opposite ends, and a workpiece conveyor mechanism 12 including a carriage 14 which is operable to transport workpieces between the opposite ends of enclosure 10, as set forth more fully hereinafter.
  • the apparatus further includes an input or loading station at one end and including an input chamber 16, a first heating station including a carbonizing and degassing furnace 18, a second heating station including a carbonizing and degassing furnace 20, a third heating station including a high fire furnace 22, a first cooling station including a cooling chamber 24, a second cooling station including a cooling chamber 26, an auxiliary cooling station including a cooling chamber 28, and an output station including an output chamber 30.
  • a green workpiece to be treated is introduced into input chamber 16 at the input station.
  • the workpiece may for example, be a powdered metal workpiece, or a workpiece including powdered metal in its composition and which requires heating to remove gases therein and sintering to achieve a cohesive mass.
  • the treating operation takes place in a controlled atmosphere of gas, such as nitrogen, and, accordingly, the green work piece introduced into input chamber 16 is thereafter protected from exposure to ambient air until it is removed from output chamber 30.
  • Enclosure 10 is adapted to contain the desired gas atmosphere and, as will become apparent hereinafter, input chamber 16 and output chamber 30 are air-lock chambers which are operable to provide for evacuation of air therefrom following insertion of a workpiece into chamber 16 and following removal of a workpiece from chamber 30.
  • the green workpiece is introduced into input chamber 16, the opposite ends of the chamber are sealed, air is evacuated therefrom and nitrogen is introduced thereinto to neutralize the chamber with respect to enclosure 10.
  • the workpiece is then introduced into enclosure 10 and is, sequentially, heated in one of the carbonizing and degassing furnaces, heated in the high fire furnace, cooled in one of the cooling chambers other than the auxiliary chamber, and transferred to output chamber 30 for removal from the apparatus.
  • the workpiece is heated in the carbonizing and degassing furnace for a predetermined period of time to elevate the temperature thereof to a desired level for achieving carbonizing and degassing.
  • the workpiece is then heated in the high fire furnace at a desired temperature for a given period of time to achieve sintering. Sintering is achieved in about onehalf the time required for degassing.
  • the workpiece is then cooled in the cooling chamber for a period of time corresponding substantially to the period of time of heating in the carbonizing and degassing furnace.
  • the provision of two carbonizing and degassing furnaces and the provision of two cooling chambers, other than the auxiliary cooling chamber provides for the apparatus to be continuously operated at a higher production rate than would be possible if only one carbonizing and degassing furnace and one cooling chamber were provided.
  • the production rate is maximized by transferring a degassed workpiece to the high fire furnace each time a workpiece is removed therefrom, and this can be achieved in accordance with the ambodiment disclosed by providing for a workpiece to be discharged alternately from the two carbonizing and degassing furnaces into the high fire furnace and by providing for the workpieces in the cooling chambers to be alternately transferred to the discharge station for removal from the apparatus.
  • Enclosure is supported on a floor or the like 32 and, in the embodiment disclosed, is comprised of a plurality of flanged box-like sections of similar structure suitably interconnected in end-to-end relationship.
  • the endmost sections are provided with end covers 10a and 10b, whereby the several sections define a tubular enclosure which is closed at its opposite ends.
  • the several sections of the enclosure are of similar structure in cross section and, as illustrated in FIG.
  • each section includes a pair of opposed parallel sidewalls 34 and 36, a top wall 38, and a bottom wall defined by a plate 40 together with components of a corresponding plunger mechanism 42 which is described more fully hereinafter.
  • Side wall 36 of each section is provided with a suitable viewing window 44 which facilitates visual observance of the operations taking place within enclosure 10, and sidewalls 34 and 36 support holding devices 45 at each station for the purpose set forth hereinafter.
  • each of the sections of enclosure 10 is associated with one of the input, heating, cooling and discharge components of the apparatus. While this structure facilitates the manufacturing and assembly operation, it will be appreciated that other enclosure structures could readily be employed.
  • Each of the chambers and heating furnaces along the length of enclosure 10 is supported on the top wall of the corresponding enclosure section and opens into the interior of enclosure 10.
  • Input and output chambers 16 and are of like structure, as are carbonizing furnaces 18 and 20, and cooling chambers 24, 26 and 28. Accordingly, the description hereinafter of the chamber and furnace structures is with regard to one of each of the different structures.
  • Input chamber 16 is best illustrated in FIGS. 2-4 of the drawing.
  • chamber 16 is comprised of a cylindrical wall 46 having a peripheral flange 48 at its lower end, a peripheral flange 50 at its upper end, and pairs of diametrically opposed longitudinally extending reinforcing ribs 52 and 53 extending between flanges 48 and 50.
  • Chamber 16 further includes an annular sealing member 54 interposed between flange 48 and top wall 38 of the corresponding enclosure section. Top wall 38 is apertured to receive sealing member 54 so that chamber 16 opens into enclosure 10.
  • Sealing member 54 includes an annular sealing surface 540 facing the interior of enclosure 10 for the purpose set forth more fully hereinafter.
  • chamber 16 The outer end of chamber 16 is adapted to be selectively opened and closed by means of a cover 56 having an operating arm 58 pivotally interconnected with one of the opposed pairs of ribs 53.
  • Cover 56 is adapted to be displaced between the open and closed positions thereof by means of a suitable pneumatic or hydraulic piston and cylinder assembly 60, and is adapted to be clamped in the closed position by means of a suitable pneumatic or hydraulic piston and cylinder assembly 62 which is operable to displace a pivotal clamping member 64 into clamping relationship with cover 56.
  • suitable fluid connections are provided for actuating piston and cylinder assemblies 60 and 62, and that suitable controls are provided for controlling fluid flow to and from these units.
  • Conveyor mechanism 12 is operable to transfer carriage 14 between the opposite ends of enclosure 10 to facilitate the transportation of workpieces to the various stations between the input and discharge chambers.
  • Any suitable conveyor mechanism can be employed for this purpose and, in the embodiment illustrated, as best seen in FIGS. 3 and 4, the conveyor mechanism includes a pair of guide tracks 66 and 68 extending longitudinally of enclosure 10 adjacent sidewalls 34 and 36, respectively, of the enclosure sections.
  • Carriage 14 is provided with corresponding pairs of wheels 70 and 72 on opposite sides thereof which support the carriage on tracks 66 and 68 for guided movement longitudinally of enclosure 10.
  • Sidewalls 34 and 36 of the enclosure sections support corresponding endless chain devices 74 and 76 which are adapted to be driven in opposite directions by a suitable motor 78 to impart movement to carriage 14 along the tracks.
  • Chain devices 74 and 76 are, of course, suitably interconnected with carriage 14 to displace the carriage along the tracks and, in the embodiment illustrated, the axles of wheels 70 and 72 extend laterally outwardly of carriage 14 to define the pivot pins between an adjacent pair of links of chains 74 and 76 to provide the chain and carriage interconnection.
  • Carriage 14 further includes a platform or bottom wall 80 provided with an opening 82 extending vertically therethrough for the purpose set forth hereinafter.
  • Carriage plate 80 is adapted to receive and support a pedestal assembly 84 which includes an annular sealing plate 86 at the lower end thereof and a workpiece supporting portion 88 extending upwardly from plate 86.
  • Pedestal 84 is adapted to be transported along enclosure 10 by carriage 14, with -or without a workpiece thereon, and is adapted to be elevated from carriage 14 as explained hereinafter to facilitate the displacement of a workpiece into and/or from a chamber of the apparatus disposed above the position in which the carriage is stopped. With regard to the illustration in FIGS.
  • pedestal 84 is adapted to be elevated for workpiece supporting portion 88 to enter chamber 16 and receive a workpiece, and for the pedestal to be lowered from chamber 16 for a workpiece thereon to be supported on carriage 14 for movement therewith.
  • the upper sealing face 86a of sealing portion 86 thereof engages the lower sealing face 54a of sealing member 54 to provide a contact seal therebetween, whereby chamber 16 is sealed from enclosure 10.
  • holding arrangements 45 are provided for holding pedestal 84 in sealed relationship with the lower end of chamber 16. More particularly, holding arrangements 45 are diametrically opposed and each includes a reciprocable cam plate 90 and a corresponding support member 91 suitably mounted on the corresponding one of the sidewalls 34 and 36 of the enclosure. Suitable hydraulic or pneumatic motors 92 are provided for reciprocating cam plates 90 horizontally relative to sealing plate portion 86 of pedestal 84.
  • cam plates 90 are displaced inwardly to underlie sealing plate 86 and thus hold the pedestal in its upper position.
  • cam plates 90 have cam surfaces 94 operable to engage and press sealing plate portion 86 against sealing plate 54 to achieve tight sealing engagement therebetween.
  • cover 56 of chamber 16 can be opened so that a workpiece to be treated can be inserted into the chamber. This, of course, exposes chamber 16 to ambient air. Following insertion of the workpiece into chamber 16 and onto the workpiece supporting portion 88 of the pedestal, cover 56 is closed and sealed, whereby the opposite ends of chamber 16 are sealed. Chamber 16 is then evacuated of air, by means not illustrated, and nitrogen is introduced into the chamber to neutralize the chamber with respect to enclosure 10.
  • plunger mechanism 42 separate from the carriage is provided at each of the stations along the length of enclosure to facilitate the elevating and lowering operation.
  • plunger mechanism 42 includes a cylinder 96 supported beneath conveyor mechanism 12 in a suitable housing 98 extending below floor 32.
  • the plunger mechanism further includes a piston component 100 which is vertically reciprocable relative to cylinder 96 in a well known manner.
  • piston 100 and cylinder 96 may be defined by a suitable hydraulic or pneumatic piston and cylinder arrangement in which the feed and discharge of operating fluid into the cylinder provides for the vertical reciprocation of piston 100 relative thereto.
  • the upper end of cylinder 96 is provided with a sealing flange 102 which cooperates with a cylinder support frame 104 and bottom wall plate 40 of the corresponding enclosure section to seal the bottom of the enclosure section.
  • the axis of piston is aligned with the axis of the chamber'thereabove.
  • the underside of sealing plate 86 and the upper end of piston 100 are provided with a cooperatively contoured interengaging structure.
  • the latter structure includes a conical recess 106 in the underside of sealing plate 86 and a corresponding conical projection 108 on the upper end of piston 100.
  • recess 106 and projection 108 interengage to shift pedestal 84 relative to the piston to assure that elevation of pedestal 84 is in proper alignment with chamber 16.
  • Peripheral flange 110 surrounding projection 108 of piston 100 engages the flat underside of sealing plate 86 to support the pedestal against tilting movement during the elevating and descending movements thereof.
  • the structures of carbonizing and degassing furnaces l8 and 20 is illustrated in FIG. 5 with regard to carbonizing furnace 20.
  • carbonizing furnace 20 is supported on top wall 38 of the corresponding section of enclosure 10.
  • the carbonizing furnace includes a chamber 112 adapted to receive a workpiece to be heated.
  • chamber 112 is cylindrical and is defined by coaxial, radially spaced apart inner and outer shells 114 and 116, respectively, of a suitable refractory material, such as silicon carbide.
  • a pair of shells or sleeves 118 and 120 of nonmagnetic material, such as carbon, are interposed between shells 114 and 116, and the top of chamber 112 is defined by an apertured end plate 122 of refractory material, such as silicon carbide.
  • An exhaust tube 124 of such refractory material communicates with the interior of chamber 112 for exhausting gases within the chamber to atmosphere.
  • a number of sleeves 121 of the material of sleeves 118 and 120 surround exhaust tube 124.
  • the lower end of chamber 112 is defined by an annular ring of refractory material 126, such as silicon carbide, and an annular metal support plate 128 which rests on top wall 38 of the enclosure section. Ring 126 and annular support plate 128 have lower faces 126a and 128a, respectively, which face inwardly of the enclosure section and define a sealing surface for cooperation with sealing plate portion 86 of pedestal 84 in the manner described hereinabove with regard to inlet chamber 16.
  • An induction heating coil assembly 130 surrounds sleeve 116 and is comprised of a plurality of convolutions 132 of a tubular conductor of conductive material such as copper embedded in a sleeve of refractory insulating material 134.
  • the coiled conductor has opposite ends adapted to be con nected across a source of alternating current 135 for energizing the conductor, and the tubular configuration of the conductor facilitates the circulation of cooling fluid therethrough to cool the conductor when the latter is energized.
  • energization of the induction heating coil induces current flow in nonmagnetic shells 118 and 120, whereby the latter are inductively heated. Accordingly, a workpiece disposed in chamber 112 is heated primarily by convection and radiation resulting from the heating of shells 118 and 120.
  • the workpiece is transported by carriage 14 to a position underlying furnace 20 and the corresponding plunger mechanism 42 is actuated to elevate the workpiece and pedestal 84 for the workpiece to enter chamber 112.
  • the induction heating coil assembly is then energized and the workpiece is heated to elevate the latter to a desired temperature and the workpiece is soaked in the furnace to achieve the removal of volatiles therefrom, which are exhausted from the furnace through exhaust tube 124 in the form of exhaust gases.
  • sealing surface 86a of plate portion 86 of the pedestal sealingly engages the lower surfaces 126a and 128a at the entrance end of chamber 112 in the manner described hereinabove with regard to input chamber 16, and cam plates 90 of the corresponding holding arrangements 45 are actuated to support the pedestal and workpiece and to tightly seal the lower end of chamber 112 during the carbonizing operation.
  • High fire furnace 22 is illustratedin FIG. 6 of the drawing and, in many respects, is of a construction similar to that of the carbonizing and degassing furnaces l8 and 20.
  • the high fire furnace includes a chamber 136 defined by inner and outer sleeves 138 and 140, respectively, of a suitable insulating material, such as silicon carbide.
  • a plurality of juxtaposed sleeves 142 of nonmagnetic material, such as carbon, are disposedbetween sleeves 138 and 140.
  • the upper end of chamber 136 is defined by an apertured end plate 144 of refractory material, such as silicon carbide, and an exhaust tube 146 of the same material cooperates with end plate 144 to vent the interior of chamber 136 to atmosphere.
  • a plurality of carbon sleeves 145 surround exhaust tube 146.
  • the lower end of chamber 136 is defined by an annular ring 148 of refractorymaterial, such as silicon carbide, and an annular metal support ring 150. Rings 148 and 150 have lower surfaces 148a and 150a, respectively, facing the interior of enclosure 10.
  • An induction heating coil assembly 152 surrounds insulating sleeve 140 and is comprised of a coil 154 of tubular conductive material, such as copper, embedded in a sleeve of insulating refractory material 156.
  • Induction heating coil 154 is adapted to be energized by a corresponding alternating current power supply 157 to inductively heat nonmatnetic sleeves 142, whereby a workpiece disposed in chamber 136 is heated by convection and radiation to elevate the temperature thereof to a desired level.
  • the high fire fumace is designed to elevate the workpiece to a sintering temperature therefor which, of course, is higher than the temperature reached in the carbonizing and degassing furnace.
  • Movement of a workpiece'into and out of chamber 136 is achieved, in the manner described hereinabove, by means of a corresponding plunger mechanism 42 disposed therebeneath. Further, it will be appreciated that sealing surface 86a of plate portion 86 of the pedestal supporting a workpiece for displacement into chamber 136 engages lower surfaces 148a and 150a at the open endof the chamber to close the latter, and that cam plates 90 of the corresponding holding arrangements 45 are actuated to hold the pedestal in its upper position and to tightly seal the opening between chamber 136 and enclosure 10.
  • cooling chambers 24 and 26 and auxiliary cooling chamber 28 The structure of cooling chambers 24 and 26 and auxiliary cooling chamber 28 is illustrated in FIG. 7 in conjunction with cooling chamber 24. In this respect,
  • the cooling chamber is comprised of a cylindrical wall 158 of suitable sheet metal having a peripheral flange 160 at the outer end thereof and a peripheral flange 162 at the inner end thereof.
  • the outer end of the cooling chamber is closed by a corresponding end plate 164 suitably interconnected with flange 160 such as by welding.
  • An annular sealing plate 166 is interposed between flange 162 and top wall 38 of the corresponding section of enclosure 10, and plate 166 includes a lower surface 166a facing inwardly of enclosure 10 for sealing engagement with upper surface 86a of sealing portion 86 of pedestal 84, as described hereinabove.
  • the opposed cam plates of the corresponding holding arrangements 45 are positioned to engage beneath sealing plate portion 86 of the pedestal to support a workpiece within the cooling chamber and to seal the entrance between the cooling chamber and enclosure 10.
  • Cooling chambers 24 and 26 are each adapted to receive and hold a hot workpiece until the temperature thereof subsides sufficiently for the workpiece to be removed from the apparatus.
  • Auxiliary cooling chamber 28 is adapted to serve the same function but with regard to a dummy workpiece D which is alternately cooled and then inserted into one of the carbonizing furnaces 18 and 20 to artificially cool the latter.
  • induction heating coil assembly is deenergized to allow furnace chamber 112 to cool.
  • a cool dummy workpiece is introduced thereinto to absorb heat and thus artifically cool the chamber.
  • ambient air surrounding cooling chambers 24, 26 and 28 will be sufficient to lower the temperatures of heated workpieces of the dummy workpiece prior to removal of the workpieces from the apparatus or use of the dummy workpiece to artificially cool a carbonizing furnace chamber.
  • external cooling in the form of liquid circulating coils or the like surrounding the cooling chambers can be employed if desired to assure sufficient cooling during the time in which a given workpiece is disposed therein.
  • the corresponding plunger mechanism 42 is retracted to its position below carriage 14.
  • the carriage is then driven by motor 78 to a position underlying cooling chamber 26.
  • the carriage is stopped and the corresponding plunger mechanism 42 is elevated to engage the underside of the pedestal closing cooling chamber 26 and supporting a workpiece therein.
  • Cam plates 90 are then withdrawn releasing the pedestal, and plunger mechanism 42 is retracted to lower the pedestal onto carriage 14.
  • the conveyor mechanism is then driven to transport carriage 14 and the pedestal and workpiece thereon to a position underlying output chamber 30.
  • the corresponding plunger mechanism 42 is then actuated to elevate the pedestal and workpiece into the output chamber.
  • carriage 14 is transported by the conveyor mechanism to a position underlying high fire furnace 22, and the corresponding plunger mechanism 42 is elevated to engage the pedestal supporting the workpiece therein, The pedestal is then released by withdrawal of cam plates 90, and the plunger mechanism is retracted to lower the pedestal and workpiece onto the carriage.
  • the carriage is then transported by the conveyor mechanism to a position underlying the now empty cooling chamber 26, and the corresponding plunger mechanism 42 is elevated to displace the hot workpiece and pedestal into the cooling chamber.
  • the corresponding cam plates 90 are actuated to hold the pedestal in its upper position the plunger mechanism is retracted to its position below the carriage.
  • the carriage is then transported to a position underlying carbonizing and degassing furnace 20 and the corresponding plunger mechanism 42 is elevated to engage the pedestal closing chamber 112 and supporting the workpiece therein.
  • the corresponding cam plates 90 are retracted to release the pedestal after which the plunger mechanism is retracted to lower the pedestal and workpiece onto carriage 14.
  • the carriage and workpiece are then displaced to a position underlying high fire furnace 22 and the corresponding plunger mechanism 42 is actuated to elevate the workpiece into the high fire furnace chamber, and the pedestal is clamped in place with respect thereto by the corresponding cam plates 90.
  • plunger mechanism 42 returns to its position beneath carriage 14 and the carriage is transported to a position underlying auxiliary cooling chamber 28.
  • Corresponding plunger mechanism 42 is elevated to engage the pedestal closing the lower end of the auxiliary cooling chamber, the pedestal is released, and the plunger mechanism is retracted to lower the pedestal and dummy workpiece onto carriage 14. The carriage is then transported to a position underlying the now empty carbonizing furnace 20, the dummy workpiece is introduced thereinto by the corresponding plunger mechanism 42, and the pedestal is locked in place by the corresponding cam plates 90.
  • carriage 14 is maintained in its position underlying carbonizing furnace 20.
  • the corresponding plunger mechanism is elevated to engage the pedestal supporting the dummy workpiece, the pedestal is released, and the plunger mechanism is retracted to lower the pedestal and dummy workpiece onto the carriage.
  • the carriage is then transported to a position underlying the auxiliary cooling chamber, and the pedestal and dummy workpiece are elevated thereinto by the corresponding plunger mechanism and the pedestal is locked in place by the corresponding cam plates.
  • carriage 14 which is now empty, is transported to a position underlying input chamber 16.
  • plunger mechanism 42 at the input station is elevated to engage the pedestal covering the lower end of the input chamber.
  • the pedestal is then released and lowered onto the carriage by retraction of the plunger mechanism, and the carriage is then moved to transport the cold workpiece to a position underlying the now empby and cooled chamber 112 of carbonizing furnace 20.
  • the corresponding plunger mechanism is actuated to elevate the cold workpiece into the furnace chamher, the pedestal is locked in place with regard thereto and the plunger mechanism is withdrawn to its position below the carriage.
  • Carriage 14 is then moved to a position underlying the now empty output chamber, plunger mechanism 42 is elevated to engage the pedestal closing the lower end thereof, the pedestal is released, and the plunger mechanism is retracted to lower the empty pedestal onto the carriage.
  • the carriage is then moved to a position underlying input chamber 16, and the corresponding plunger mechanism is actuated to elevate the pedestal to close the lower end of the chamber.
  • Cam plates lock the pedestal in place after which the plunger mechanism is retracted.
  • Carriage 14 is then transported to a position underlying cooling chamber 24, and the preceeding sequence is repeated to achieve displacement of the workpiece from chamber 24 to output chamber 30, the transfer of a heated workpiece from high fire furnace 22 to cooling chamber 24, the transfer of a heated workpiece from carbonizing furnace 18 to high fire furnace 22, the transfer of the dummy workpiece from auxiliary cooling chamber 28 to carbonizing furnace l8 and 13 back, the loading of a new workpiece into input chamber, and the transfer of the new workpiece into carbonizing furnace l8.
  • motor 78 for conveyor mechanism 12 is provided with suitable controls which are programmed to achieve displacement of carriage 14 to the several stations thereof in the desired sequence and in timed relationship with regard to the functions to be achieved.
  • programming will include controls for actuating the plunger mechanisms 42 and pedestal holding cam plates 90 for these components to function as desired.
  • Such controls do not form a part of the present invention and, accordingly, are not disclosed in detail.
  • certain changes can be made therein without departing from the basic sequencing of a workpiece through the apparatus. For example, it may be that under certain operating conditions, the carbonizing and degassing furnaces will cool sufficiently when de-energized to negate the necessity of artificial cooling by the dummy workpiece, whereby the artificial cooling step can be eliminated.
  • pedestal clamping arrangements other than that defined by reciprocating cam plates 90 can be employed to releaseably hold the pedestals in place relative to the lower ends of the chambers and to seal the lower ends of the chambers with respect to the interior of enclosure 10.
  • pedestal and workpiece elevating mechanisms other than reciprocating fluid actuated plungers can be employed.
  • cooperable rack and inion mechanisms could be employed for reciprocating the plunger mechanisms, or a suitable elevator mechanism could be associated with carriage 14 for movement therewith and for achieving the elevating and lowering functions at each station of the apparatus.
  • input, discharge, furnace and cooling chamber structures other than those specifically illustrated and described could readily be provided without departing from the principles of the present invention, as could conveyor arrangements for transporting the pedestal and workpiece components relative to the enclosure.
  • conveyor arrangements for transporting the pedestal and workpiece components relative to the enclosure.
  • pedestal structures other than that specificially illustrated herein can be employed, and that the pedestals and plunger mechanisms can have interengaging contours to achieve alignment of the workpiece and pedestal relative to a chamber other than the conical projection and recess structure disclosed.
  • a heat treating furnace comprising an input station, a heating station, a cooling station and an output station, a vertically fixed carriage movable along a horizontal path relative to said stations, enclosure means for said carriage and including top wall means spaced above said carriage and overlying said path, chamber means at each of said stations supported on said top wall means and opening therethrough, means to heat said chamber means at said heating station, means to position said carriage along said path at each of said stations in alignment with the opening into the chamber means at the corresponding station, workpiece support and chamber closure means separate from and movable with said carriage and displaceable vertically from said carriage at each of said stations between a first position on said carriage and a second position spaced from said carriage and closing the opening into the chamber means at the corresponding station, means at each of said stations separate from said carriage and displaceable relative thereto to move said support and closure means relative to said carriage between said first and second positions, and means separate from said carriage to hold said support and closure means in said second position.
  • said support and closure includes plate means adapted to overlie the peripheral edge of a chamber opening, and said means to hold said support and closure means in said second position includes extendable and retractable clamping means operable when extended to sealingly clamp said plate means against the peripheral edge of said opening.
  • said support and closure means includes plate means adapted to overlie the peripheral edge of a chamber opening, and said means to hold said support and closure means in said second position includes extendable and retractable clamping means operable when extended to sealingly clamp said plate means against the peripheral edge of said opening.
  • said clamping means includes opposed horizontally reciprocable cam plates supported adjacent said peripheral edge and spaced apart when retracted for said means to pass therebetween, said cam plates when extended engaging under said plate means to cam said plate means against said peripheral edge, and drive means to displace said cam plates between the extended and retracted positions thereof.
  • each said chamber means at said input and output stations has an opening spaced from said enclosure means and a corresponding closure member for said opening, means to move said closure member between open and closed positions with respect to the opening, and means to sealingly clamp said closure member in the closed position thereof.
  • a heat treating furnace comprising, an elongate tubular housing closed at its opposite ends and of generally gas tight construction, said housing including top wall means, a tubular workpiece input chamber on said top wall means at one end of said housing and having an open first end facing said top wall means and a second end spaced from said top wall means, means to selectively open and sealingly close said second end of said input chamber, a tubular workpiece output chamber on said top wall means at the other end of said housing and having an open first end facing said top wall means and a second end spaced from said top wall means, means to selectively open and sealingly close said second end of said output chamber, a heating chamber on said top wall means between said input and output chambers and having an open first end facing said top wall means and a second end spaced from said top wall means and vented to atmosphere, said heating chamber including chamber wall means of nonmagnetic material and induction heating coil means surrounding said chamber wall means in inductive heating relationship therewith, a tubular cooling chamber on said top wall means between said heating chamber means and output chamber means, said
  • said means to selectively open and sealingly close said second ends of said input and output chambers includes corresponding cover members for said chambers, drive means for moving each cover member between open and closed positions relative to the corresponding chamber, and means to clamp the cover members in the closed positions thereof,
  • said carriage means includes a wheeled carriage and track means supporting said carriage for rolling movement along said path.
  • said means to releasably hold said pedestal means includes extendable and retractable clamping means supported adjacent said top wall means and engaging under said sealing flange means when in the extended position thereof, and means to move said clamping means between the extended and retracted positions thereof.
  • said clamping means includes opposed horizontally reciprocable cam plates having cam surfaces engaging beneath said sealing flange means when said cam plates are in the extended positions thereof.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Tunnel Furnaces (AREA)
US435677A 1974-01-23 1974-01-23 Method and apparatus for carbonizing and degassing workpieces Expired - Lifetime US3926415A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US435677A US3926415A (en) 1974-01-23 1974-01-23 Method and apparatus for carbonizing and degassing workpieces
CA217,031A CA1020344A (fr) 1974-01-23 1974-12-27 Appareil et methode de carburation et de degazage de pieces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US435677A US3926415A (en) 1974-01-23 1974-01-23 Method and apparatus for carbonizing and degassing workpieces

Publications (1)

Publication Number Publication Date
US3926415A true US3926415A (en) 1975-12-16

Family

ID=23729339

Family Applications (1)

Application Number Title Priority Date Filing Date
US435677A Expired - Lifetime US3926415A (en) 1974-01-23 1974-01-23 Method and apparatus for carbonizing and degassing workpieces

Country Status (2)

Country Link
US (1) US3926415A (fr)
CA (1) CA1020344A (fr)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4237359A (en) * 1977-12-23 1980-12-02 Thyssen Industrie Ag Method and apparatus for the electroinduction heating of metal workpieces
US4398076A (en) * 1981-03-06 1983-08-09 Lester Hanson Product recovery method and system for hydrocarbon materials
JPS59152229A (ja) * 1983-02-16 1984-08-30 Canon Inc 光学素子成形装置
US4510363A (en) * 1983-08-08 1985-04-09 The United States Of America As Represented By The United States Department Of Energy Kiln for hot-pressing compacts in a continuous manner
US4528434A (en) * 1982-03-23 1985-07-09 Voest-Alpine Aktiengesellschaft Coiler-furnace unit
EP0296102A1 (fr) * 1987-06-03 1988-12-21 Pierre Beuret Installation à plusieurs éléments pour des traitements thermiques
US4818833A (en) * 1987-12-21 1989-04-04 United Technologies Corporation Apparatus for radiantly heating blade tips
WO1994014714A1 (fr) * 1992-12-22 1994-07-07 New Life Foundation Procede de fabrication d'articles en verre expanse
EP0785402A1 (fr) * 1996-01-17 1997-07-23 Pierre Beuret Installation pour le traitement thermique d'une charge de pièces métalliques
EP1193317A1 (fr) * 2000-09-27 2002-04-03 Patherm SA Installation pour le traitement thermique de charges de pièces métalliques
US20030116894A1 (en) * 2001-12-26 2003-06-26 Korwin Michel J. Multi-cell thermal processing unit
US6796483B1 (en) * 1999-11-08 2004-09-28 Pink Gmbh Vakuumtechnik Method and device for producing a soldered joint
US20070128569A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Furnace alignment system
US20070125769A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
CN103710505A (zh) * 2012-10-08 2014-04-09 易普森国际有限公司 气密的、加载保护气体的工业用炉，特别是箱式炉、连续送料式炉、转底炉或环形炉
US20140186786A1 (en) * 2011-07-04 2014-07-03 Kazumi Mori Continuous firing furnace

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1064481A (en) * 1912-06-19 1913-06-10 Hermann Hillebrand Jr Annealing apparatus.
US1073235A (en) * 1912-06-19 1913-09-16 Hermann Hillebrand Jr Annealing apparatus.
US1118869A (en) * 1914-11-24 Carl Kugel Annealing furnace.
US1388575A (en) * 1919-09-26 1921-08-23 Charles F Kenworthy Furnace
US1617056A (en) * 1926-04-10 1927-02-08 Charles F Kenworthy Inc Furnace
US1825380A (en) * 1928-06-29 1931-09-29 Int Nickel Co Annealing furnace
US1854374A (en) * 1930-04-11 1932-04-19 American Electric Furnace Comp Electric furnace
US1876960A (en) * 1929-01-14 1932-09-13 Charles F Kenworthy Inc Annealing furnace
US3717740A (en) * 1971-07-09 1973-02-20 Park Ohio Industries Inc Slab heating device

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1118869A (en) * 1914-11-24 Carl Kugel Annealing furnace.
US1064481A (en) * 1912-06-19 1913-06-10 Hermann Hillebrand Jr Annealing apparatus.
US1073235A (en) * 1912-06-19 1913-09-16 Hermann Hillebrand Jr Annealing apparatus.
US1388575A (en) * 1919-09-26 1921-08-23 Charles F Kenworthy Furnace
US1617056A (en) * 1926-04-10 1927-02-08 Charles F Kenworthy Inc Furnace
US1825380A (en) * 1928-06-29 1931-09-29 Int Nickel Co Annealing furnace
US1876960A (en) * 1929-01-14 1932-09-13 Charles F Kenworthy Inc Annealing furnace
US1854374A (en) * 1930-04-11 1932-04-19 American Electric Furnace Comp Electric furnace
US3717740A (en) * 1971-07-09 1973-02-20 Park Ohio Industries Inc Slab heating device

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4237359A (en) * 1977-12-23 1980-12-02 Thyssen Industrie Ag Method and apparatus for the electroinduction heating of metal workpieces
US4398076A (en) * 1981-03-06 1983-08-09 Lester Hanson Product recovery method and system for hydrocarbon materials
US4528434A (en) * 1982-03-23 1985-07-09 Voest-Alpine Aktiengesellschaft Coiler-furnace unit
JPS59152229A (ja) * 1983-02-16 1984-08-30 Canon Inc 光学素子成形装置
US4510363A (en) * 1983-08-08 1985-04-09 The United States Of America As Represented By The United States Department Of Energy Kiln for hot-pressing compacts in a continuous manner
EP0296102A1 (fr) * 1987-06-03 1988-12-21 Pierre Beuret Installation à plusieurs éléments pour des traitements thermiques
US4818833A (en) * 1987-12-21 1989-04-04 United Technologies Corporation Apparatus for radiantly heating blade tips
WO1994014714A1 (fr) * 1992-12-22 1994-07-07 New Life Foundation Procede de fabrication d'articles en verre expanse
EP0785402A1 (fr) * 1996-01-17 1997-07-23 Pierre Beuret Installation pour le traitement thermique d'une charge de pièces métalliques
US6796483B1 (en) * 1999-11-08 2004-09-28 Pink Gmbh Vakuumtechnik Method and device for producing a soldered joint
EP1193317A1 (fr) * 2000-09-27 2002-04-03 Patherm SA Installation pour le traitement thermique de charges de pièces métalliques
US20030116894A1 (en) * 2001-12-26 2003-06-26 Korwin Michel J. Multi-cell thermal processing unit
EP1323995A3 (fr) * 2001-12-26 2003-11-05 Nitrex Metal Inc Unité de traitement thermique multichambre
US6902635B2 (en) 2001-12-26 2005-06-07 Nitrex Metal Inc. Multi-cell thermal processing unit
US20070128569A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Furnace alignment system
US20070125769A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
US7745764B2 (en) 2005-12-07 2010-06-29 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
US7789660B2 (en) * 2005-12-07 2010-09-07 Ajax Tocco Magnethermic Corporation Furnace alignment system
US20140186786A1 (en) * 2011-07-04 2014-07-03 Kazumi Mori Continuous firing furnace
CN103710505A (zh) * 2012-10-08 2014-04-09 易普森国际有限公司 气密的、加载保护气体的工业用炉，特别是箱式炉、连续送料式炉、转底炉或环形炉
US20140106287A1 (en) * 2012-10-08 2014-04-17 Ipsen, Inc. Industrial Heat Treating Furnace That Uses a Protective Gas
US9890999B2 (en) * 2012-10-08 2018-02-13 Ipsen, Inc. Industrial heat treating furnace that uses a protective gas

Also Published As

Publication number Publication date
CA1020344A (fr) 1977-11-08

Similar Documents

Publication Publication Date Title
US4118016A (en) Continuous heat treating vacuum furnace
KR0181176B1 (ko) 진공하에서의 연속 열처리 수행장치
US20020146659A1 (en) Arrangement and method for transporting metallic work pieces, and system for heat treatment of said work pieces
US3659831A (en) Integral quench furnace and transfer mechanism
US3447788A (en) Heat treating method and apparatus
GB1569005A (en) Walking beam apparatus for treating work
US3522357A (en) Vacuum furnace having a liquid quench and a vertically movable work holder
JP6184718B2 (ja) 熱処理炉
EP0121627B1 (fr) Dispositif pour compressions isostatiques à chaud
JP2009185349A (ja) 多室型熱処理炉
JPS5855526A (ja) 雰囲気熱処理装置
US4415145A (en) Metal charge treatment apparatus
US4720615A (en) Induction sintering process and apparatus
US4802844A (en) High capacity, retractable furnace hearth
US3588305A (en) Electrically heated vessel enclosed car bottom furnace system
US4833302A (en) Apparatus and process for firing ceramics
CN212235315U (zh) 一种药材加工用煅药炉
CA1236293A (fr) Mecanisme de chargement d'un four de traitement thermique avec des pieces a traiter
JPH07110989B2 (ja) 真空処理装置
CA1125010A (fr) Four sous vide de traitement thermique en continu
JP2589823Y2 (ja) 連続焼入装置
JPH0320678B2 (fr)
US3687191A (en) Vacuum casting furnace
JP2000308874A (ja) 材料を真空熱的に処理するための設備
JPS62290858A (ja) 熱処理炉