US3804584A - Pusher furnace - Google Patents

Pusher furnace Download PDF

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Publication number
US3804584A
US3804584A US00340006A US34000673A US3804584A US 3804584 A US3804584 A US 3804584A US 00340006 A US00340006 A US 00340006A US 34000673 A US34000673 A US 34000673A US 3804584 A US3804584 A US 3804584A
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US
United States
Prior art keywords
furnace
metallic
workpieces
zone
outlet
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
US00340006A
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English (en)
Inventor
G Herr
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.)
Koppers Wistra Ofenbau GmbH
EOn Ruhrgas AG
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Koppers Wistra Ofenbau GmbH
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Assigned to RUHRGAS AG, D-4300 ESSEN, GERMANY reassignment RUHRGAS AG, D-4300 ESSEN, GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WISTRA GMBH THERMOPROZESSTECHNIK
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/02—Skids or tracks for heavy objects
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
    • F27B9/22—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace on rails, e.g. under the action of scrapers or pushers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00—Casings; Linings; Walls; Roofs
    • F27D2001/0046—Means to facilitate repair or replacement or prevent quick wearing
    • F27D2001/005—Removable part or structure with replaceable elements

Definitions

  • ABSTRACT An elongated furnace for heat treatment of metallic workpieces which are pushed through the heated furnace chamber along guide means extending from an inlet at one end of the furnace chamber to an outlet at the other end thereof.
  • the elongated guide means comprise metallic elements supported on and in direct contactwith water-cooled pipes extending upwardly spaced from the bottom wall of the furnace from the inlet towards the outlet, and a ceramic hearth portion in the region of the outlet and having an upper guide face flush with upper faces of said metallic elements.
  • the present invention relates to elongated furnaces for heat treatment of metallic workpieces such as metal blocks, slabs or the like-in which the metallic worpieces are pushed in longitudinal direction through the furnace on guide rails mounted on metal pipes through which cooling water is circulated and in which the metallic workpieces, while being pushed along these guide rails, are heated from above and below.
  • guide rail constructions for furnaces of the mentioned type are know in various construction forms.
  • the guide rails at the inlet end of the furnace chamber as metallic wear strips which are welded onto upper portions of pipes through which cooling water is circulated
  • the guide rails are constructed from metallic glide members which are without heat insulation loosely set onto the pipesand removably held thereon.
  • the guide rails are formed from metallic elements with pressureresistant heat-insulatin'g members sandwiched between the metallic elements and the water-cooled pipes, and in which the. heat-insulating' members and the heatresistant metallic'members are held on the pipes by metallic frames welded to the pipes.
  • Pusher furnaces with guide rail means of the abovementioned type have given satisfactory results especially with regard to the required uniform heating of the workpieces at very high temperatures.
  • the use of the insolated'metallic guide members at the last part of the guidev rails means is not possible .or desirable for constructive or operative reasons. This is, for instance, the case when the pusher furnace has also a lateral discharge opening forpushing the heated workpieces in a direction transverse to the longitudinal axis of the guide rail means out of the furnace.
  • the metallic elements which are supported by means of heat-insulating. members on the water-cooled pipes,
  • the pusher furnace has an elongated furnace chamber comprising a first zone adjacent the furnace inlet, a second zone adjacent the furnace outlet and an intermediate zone between the first and the second zones.
  • Elongated guide means extend longitudinally through the furnace and comprise elongated metallic water-cooled guide means extending longitudihearth portion in said second zone forming an upper I guide face flush with the upper faces of the metallic guide means.
  • Heating means are provided in the furnace for heating the furnace chamber and the metallic workpieces pushedthereto.
  • the elongated metallic guide means preferably comprise at'least two transversely spaced metal pipes extending longitudinally through the first and intermediate zones for circulation of cooling water therethrough, and'a metallic wearv strip is welded in the first zone to an upper portion of each pipe, wihereasa plurality of metallic slide members are mounted inflthe intermediate zoneof each of the pipes, while means for maintaining the slide member indirect contact with an upper portion of the respective pipe are provided to hold the slide members in contactwith respectivepipe removable therefrom.
  • the heating means comprise burner means arranged for heating the' metallic workpieces from above and below while the latter are pushed along the metallic guide means and the burners are prefera bly arranged in such a manner so as to heat the workpieces as they are pushed along the guide means to a higher degree in the intermediate zones than in the first and the second zone.
  • the wear strips are preferably formed from chrome second zone permitting the workpieces to be pushed out of the furnace chamber in a direction transverse to the longitudinal direction thereof and this second outlet is preferably arranged in the furnace wall which is located laterally of the ceramic hearth portion.
  • FIG. 1 is a longitudinal section through the furnace according to the present invention.
  • FIG. 2 is a partial transverse cross section taken along the line [I -II of FIG. 1, drawn to an enlarged scale; and
  • I FIG. 3 is a partial transverse cross section taken along the line Ill-Ill of FIG. 1, likewise drawn to an enlarged scale.
  • FIG. 1 schematically illustrates in longitudinal cross section an elongated furnace 1, the walls of which define an elongated furnace chamber having an inlet la at the right end, as viewed in FIG. 1, and an outlet 1b at the left end.
  • the interior of the furnace chamber may be considered as divided into three zones, that is a first zone in the region of the inlet la where the top wall of the furnace is slightly lower than in the remainder of the furnace, a second zone in the region of the outlet, that is towards the left of the downward depression in the top wall of the furnace, and an intermediate zone between the first and the second zone.
  • Elongated guide means extend in longitudinal direction through the furnace chamber from the inlet la to the outlet lb along which metallic workpieces, not shown in the drawings, are to be pushed through the furnace in the direction indicated by the arrow A.
  • the elongated guide means comprise in the first and the intermediate zone at least two transversely spaced metal pipes S,
  • FIG. 1 only the front one is shown in FIG. 1, through which cooling water from a source not shown in the drawing may be circulated.
  • a plurality of wear strips 11 are welded to the upper portion of the cooling pipe 5 and these wear strips which may have preferably a square or rectangular cross section have an upper surface along which the metallic workpieces to be treated in the furnace are. pushed.
  • a plurality of slide members 13 of a height greater than those of the wear strips are placed on the upper portions of the pipes 5 with the lower ends of the slide members 13 have to be flush, that is in one plane with the upper surfaces .of the wear strips 11.
  • the cross section of the pipes on which the slide members are removably supported is preferably reduced as compared to the cross section of the pipe portions which support the wear strips, as clearly shown in the figures of the drawing.
  • the pipes 5 are supported spaced from the bottom wall of the furnace on longitudinally displaced frame members comprising upright pipes 7 and transversely arranged pipes 9.
  • the guide means comprise a ceramic hearth portion 17 having an upper face flush with the upper faces of the slide member 13 and the wear strips 11.
  • the interior of the furnace chamber is heated by a plurality'of burners 3, only schematically indicated in FIG. 1 by the center lines of the burners, and it will be seen that the burners are arranged in such a manner that workpieces, when pushed in longitudinal direction through the furnace, are heated to a higher degree in the intermediate zone than in the first and second zones.
  • the height of the slide members 13 is chosen in such a mannner that the cooling of the slide members 13 by the water circulating through the pipes 5, even at the highest temperatures and the most unfavorable operating conditions, is great enough that the hottest portions of the slide members 13 will assume only a temperature in which the material from which the slide members 13 are formed will still have sufficient rigidity and load-bearing capacity.
  • the slide members 13 are preferably formed from high heat-resistant steel, for instance a cobalt steel alloy containing up to about 50 percent cobalt, whereas the wear strips 11 may be formed from chrome-nickel alloy steel.
  • the bottom faces of these workpieces will be cooled along portions thereof in contact with the wear strips 11 or the slide members 13, so that these portions of the metallic workpieces will have a temperature smaller than the remainder thereof.
  • the ceramic hearth portion 17 is provided in the second zone in which a temperature equalization throughout the workpieces will take place.
  • the furnace is preferably provided adjacent itsleft end, as viewed in FIG. 1, with a lateral opening 19 in the side wall of the furnace through which the heated workpieces may be pushed out of the furnace by a device not shown in the drawing.
  • the pusher furnace according to the present invention may be successfully used in all cases in which the above-described construction and operating conditions are present.
  • the construction may also be used when existing furnaces, which have already a ceramic hearth portion at the outlet end, are to be rebuilt, while maintaining the ceramic hearth portion.
  • I v i It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of pusher furnaces differing from the type described above.
  • a pusher furnace for heat treatment of metallic workpieces said furnace having wall means including a bottom wall defining an elongated furnace chamber having an inlet at one end of said elongated furnace chamber and an outlet at the other end thereof, said furnace chamber comprising a first zone adjacent said inlet, a second zone adjacent said outlet and an intermediate zone between said first and said second zones; elongated guide means extending longitudinally through said furnace and comprising elongated metallic watercooled guide means extending only through said first and said intermediate zones spaced from said bottom wall and having upper faces along which metallic workpieces are to be pushed from said inlet towards said outlet, and a ceramic hearth portion in said second zone having an upper ceramic guide face flush with said upper faces of said metallic guide means; and heating means in said furnace for heating said furnace chamber and metallic workpieces pushed therethrough.
  • said elongated metallic guide means comprise at least two transversely spaced metal pipes extending longitudinally through said first and said intermediate zones and arranged for circulation of cooling water therethrough, metallic wear strips welded in said first zone to an upper portion of each pipe and. a plurality of metallic slide membersmounted in said intermediate zone on each of said pipes, and means for main-taining said slide members in direct contact with an upper portion of the respective pipe.
  • a furnace as defined in claim 2, wherein said means for maintaining said slide members in direct contact with saidpipes comprisemetallic ribs welded to said pipes and projecting upwardly therefrom to opposite sides of of said slide members.
  • heating means comprises burner means arranged for heating metallic workpieces pushed along said metallic guide means from above and below.
  • ers are arranged to heat workpieces as they are pushed along said guide means to a higher degree in said intermediate zone than in said first and said second zones.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Furnace Charging Or Discharging (AREA)
US00340006A 1972-09-23 1973-03-12 Pusher furnace Expired - Lifetime US3804584A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19722246772 DE2246772A1 (de) 1972-09-23 1972-09-23 Stossofen

Publications (1)

Publication Number Publication Date
US3804584A true US3804584A (en) 1974-04-16

Family

ID=5857188

Family Applications (1)

Application Number Title Priority Date Filing Date
US00340006A Expired - Lifetime US3804584A (en) 1972-09-23 1973-03-12 Pusher furnace

Country Status (6)

Country Link
US (1) US3804584A (it)
JP (1) JPS4965911A (it)
DE (1) DE2246772A1 (it)
FR (1) FR2205183A5 (it)
GB (1) GB1390875A (it)
IT (1) IT991415B (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056351A (en) * 1975-02-07 1977-11-01 Koppers-Wistra-Ofenbau Gmbh Workpiece-engaging element for furnaces
US4106894A (en) * 1975-12-19 1978-08-15 Bertin & Cie Apparatus for heat treating fragmented materials
US4936771A (en) * 1987-08-26 1990-06-26 Sidwell Clarence W Skid mark erasure system
US5007824A (en) * 1987-08-26 1991-04-16 Sidwell Clarence W Skid mark erasure system
US20070128568A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus to provide continuous movement through a furnace

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2120448A (en) * 1982-05-06 1983-11-30 Atomic Energy Authority Uk Improvements in nuclear reactors
FR3135943B1 (fr) 2022-05-31 2024-04-12 Psa Automobiles Sa Procede de pilotage d’une machine electrique, produit-programme d’ordinateur et vehicule correspondants.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB785960A (en) * 1954-12-29 1957-11-06 Thermo Industrieofenbau G M B Composite refractory rail for pusher-type furnaces
US3081073A (en) * 1960-05-31 1963-03-12 Bloom Eng Co Inc Metal heating furnace apparatus
US3214152A (en) * 1962-10-04 1965-10-26 Wistra Ofenbau G M B H Pusher-type furnace
US3637198A (en) * 1970-01-12 1972-01-25 Koppers Wistra Ofenbau Gmbh Furnace for heat treating of metallic workpieces

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB785960A (en) * 1954-12-29 1957-11-06 Thermo Industrieofenbau G M B Composite refractory rail for pusher-type furnaces
US3081073A (en) * 1960-05-31 1963-03-12 Bloom Eng Co Inc Metal heating furnace apparatus
US3214152A (en) * 1962-10-04 1965-10-26 Wistra Ofenbau G M B H Pusher-type furnace
US3637198A (en) * 1970-01-12 1972-01-25 Koppers Wistra Ofenbau Gmbh Furnace for heat treating of metallic workpieces

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056351A (en) * 1975-02-07 1977-11-01 Koppers-Wistra-Ofenbau Gmbh Workpiece-engaging element for furnaces
US4106894A (en) * 1975-12-19 1978-08-15 Bertin & Cie Apparatus for heat treating fragmented materials
US4936771A (en) * 1987-08-26 1990-06-26 Sidwell Clarence W Skid mark erasure system
US5007824A (en) * 1987-08-26 1991-04-16 Sidwell Clarence W Skid mark erasure system
US20070128568A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus to provide continuous movement through a furnace
US7507087B2 (en) * 2005-12-07 2009-03-24 Ajax Tocco Manethermic Corporation Method and apparatus to provide continuous movement through a furnace

Also Published As

Publication number Publication date
IT991415B (it) 1975-07-30
GB1390875A (en) 1975-04-16
JPS4965911A (it) 1974-06-26
DE2246772A1 (de) 1974-03-28
FR2205183A5 (it) 1974-05-24

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Owner name: RUHRGAS AG, D-4300 ESSEN, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WISTRA GMBH THERMOPROZESSTECHNIK;REEL/FRAME:004368/0463