US3606288A - Furnace seal - Google Patents

Furnace seal Download PDF

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Publication number
US3606288A
US3606288A US7721A US3606288DA US3606288A US 3606288 A US3606288 A US 3606288A US 7721 A US7721 A US 7721A US 3606288D A US3606288D A US 3606288DA US 3606288 A US3606288 A US 3606288A
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US
United States
Prior art keywords
furnace
atmosphere
elements
seal
workpiece
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
US7721A
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English (en)
Inventor
William M Bloom
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.)
Allegheny Ludlum Corp
Pittsburgh National Bank
Original Assignee
Allegheny Ludlum Steel Corp
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Publication date
Application filed by Allegheny Ludlum Steel Corp filed Critical Allegheny Ludlum Steel Corp
Application granted granted Critical
Publication of US3606288A publication Critical patent/US3606288A/en
Assigned to ALLEGHENY LUDLUM CORPORATION reassignment ALLEGHENY LUDLUM CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). 8-4-86 Assignors: ALLEGHENY LUDLUM STEEL CORPORATION
Assigned to PITTSBURGH NATIONAL BANK reassignment PITTSBURGH NATIONAL BANK SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ALLEGHENY LUDLUM CORPORATION
Anticipated expiration legal-status Critical
Assigned to PITTSBURGH NATIONAL BANK reassignment PITTSBURGH NATIONAL BANK ASSIGNMENT OF ASSIGNORS INTEREST. RECORDED ON REEL 4855 FRAME 0400 Assignors: PITTSBURGH NATIONAL BANK
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F27D1/18—Door frames; Doors, lids or removable covers
    • 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

Definitions

  • a sealing system for a furnace such as a continuous bar annealing furnace having a plurality of sealing elements supported across the opening to the furnace in a side-by-side relationship. Each element of the seal has two parallel planar sides in alignment with the direction of entry into the furnace.
  • Material entering the furnace contacts one or more elements causing them to be displaced, permitting the material to enter the furnace.
  • the dimension of the planar sides of each element in the direction of displacement is of such magnitude that the side of one element remains in a continually overlapping relationship with the side of anadjacent element when one of the elements is displaced by the material entering the furnace.
  • the purpose of this invention is to provide an effective atmosphere seal at the entry or exit ends of a chamber, partigularly one having an internal atmosphere different than that of the environment of the furnace, such as a continuous bar annealing furnace having a hydrogen atmosphere.
  • Continuous roller-hearth, atmosphere-type, tool steel bar annealing furnaces are designed to provide close temperature and atmosphere controls, so that as the temperature of charge material is increased or decreased within the furnace, the composition of the atmosphere may be changed to maintain an atmosphere neutral to the carbon content of the steel. In this manner the carbon content of the annealed bar after the annealing will be substantially equivalent to its carbon content before the anneal.
  • Endothermic and exothermic gases are continuously admitted to the furnace at various predetermined points along its length in metallurgically prescribed quantities and ratios, to obtain the desired variation in atmosphere gas .composition and temperature.
  • the means to control the quantity of gas flow out of the furnace ends should be able to maintain a controlled atmosphere gas flow rate under varying environmental conditions such as when the conditions at the furnace ends vary, or the bar load passing through the furnace ends varies the cross-sectional area of the seal.
  • Positive internal furnace pressure greater than environmental pressure is required in isolated atmosphere furnaces, such as at a sealing chamber to prevent infiltration of the environment atmosphere through the seals and into the furnace, causing a contamination of the atmosphere therein.
  • This internal furnace pressure acting across the seals must also be great enough to overcome the external air impingement of the environmental disturbances in the vicinity of the furnace, such as the opening of building doors, etc.
  • the effectiveness of the seals and the quantity of furnace atmosphere gas requirements to maintain a positive pressure within the furnace are dependent upon the seals gas flow resistance, determined by the cross-sectional flow area, the flow area shape for flow coefficient, and the length of flow path for frictional factors.
  • An effective seal design should minimize gas leakage through the seals by providing suflicient flow resistance under all conditions of operation, to maintain a continuing, but minimized flow of atmosphere from the furnace to the environment outside.
  • the seal should have sufficient flow resistance to make any influence of external environment atmosphere disturbance on the seals negligible, both when the seals are in the closed position as well as the open position as during the charging of the furnace.
  • This open area, or side hole enables substantially large quantities of furnace atmosphere to escape, thereby requiring large quantities of atmosphere make-up cast to retain the desired furnace pressure. Further, due to the side holes the flow rate of atmosphere at the seals varies substantially with changes in the seal cross-section contour between the no load condition and the loaded condition thus, varying the internal bias furnace atmosphere points.
  • the conventional baffle seals are also substantially influenced by abrupt changes in external environment atmosphere such that the flow rate of furnace atmosphere across the seal varies, affecting the atmosphere profile within the furnace. Disturbing the atmosphere profile within the furnace causes mixing and a more homogeneous mixture of gases in the different section. The quality of many annealing processes is directly dependent upon the attainment of a definite, tapered, reproducible furnace atmosphere composition along furnace length.
  • the furnace atmosphere disturbances allowed by conventional seals materially affect the desired furnace atmosphere profile and quality of the anneal.
  • the seals of my invention enable the establishment of a sub stantially continuous atmosphere gas flow rate across them to the external atmosphere which is relatively unaffected by the entrance or exiting of material or various external wind effects.
  • the utilization of my seals permits the establishment of a stable, profiled atmosphere along the furnace length, enabling the production of a uniform, high quality anneal.
  • a seal for a chamber such as an isolated atmosphere furnace having a plurality of elements in a side-by-side relationship, each element having two substantially parallel sides and joined by a separator extending therebetween.
  • the individual elements are supported across the opening to said chamber and adapted to be individually displaced by a workpiece entering therein.
  • the dimensions of said parallel sides are of predetermined width such that adjacent sides of elements maintain a continually overlapping relationship when an element is displaced by an entering workpiece.
  • FIG. 1 is a side elevation of the seals of my invention as embodied in a continuous bar annealing furnace shown in cross section.
  • FIG. 3 is a side elevation of a seal element of my invention.
  • FIG. 4 is a view looking in the direction of arrows IVIV of FIG. 3.
  • reference numeral 2 indicates the entry portion of a furnace, such as a continuous bar annealing furnace, having an entry vestibule 4 separated from the furnace proper 6 by means such as a heat shield 8.
  • the entry vestibule 4 of the annealing furnace has a gas-tight envelope 10 supported by structure 12.
  • bafiles 14 are suspended from the overhead portion of the vestibule, being usually an alloy sheet welded in a gas-tight manner to the overhead of envelope 10.
  • supporting rods 15 extend across the vestibule 4, carrying sealing curtains 16, composed of individual sealing elements 18, such as those of my invention and later described.
  • Vestibule 4 is further provided with rolls 20 supported by the furnace structure in a manner well known in the art for supporting and conveying a workpiece W such as a bar of steel to be annealed.
  • seal element 18 has two parallel planar sides 22 which are separated and supported by partition 24.
  • partition 24 forms a third side which, when the element 18 is hung within the vestibule 4, faces the approaching workpiece W.
  • Element 18 is adapted with means 26 to mount the element on the rods 15.
  • the mounting means 26 is a sleeve 28 attached to both the sides 22 and partition 24, forming a gas-tight jointure therewith which enables the element to be rotated as illustrated in FIG. 1 at 30 when workpiece W enters the vestibule 4.
  • Sides 22 of element 18 are further adapted to be triangular in shape and oriented such that their lateral dimension continually increases away from the mounting means 26 toward end 32.
  • end 32 is predetermined to be greater than the vertical displacement of element 18 upon the entry of workpiece W, to insure a continually overlapping relationship of the adjacent sides 22, as illustrated at 34 of FIG. 1.
  • element 18 is further adapted so that edge 32 presents a sloping aspect to the retreating workpiece passing the element 18-.
  • the seals of this invention are mounted in rows along the baffle 14 being suspended from the transverse rod 15 forming a series of articulating sealing baffie-like elements.
  • the individual elements 18 swing upward to a position as at 30, being displaced by the workpiece W passing into the furnace vestibule 4, on rollers 20.
  • Elements 1-8 in the preferred embodiment are hung to form an angle A when closed, offset from the vertical plane in the direction of bar travel. Such an angle permits a tight closer of the element 18 of the edge of side 24 against sealing means as plate 38.
  • the offset hanging of element 18 also prevents wedging or lock-up of the element against the bottom sealing means which might otherwise happen if the element were allowed to swing approximately to the vertical position upon passage of the workpiece W.
  • the offset hang-ing of the element 18 also reduces the area above the element required for the .full displacement of the element 18 upon the passage of a workpiece W.
  • sides 22 have sufficient lateral dimension to form a continuous overlapping relationship as at 34 between the closed and opened adjacent elements.
  • the trailing edge 32 of each element in the preferred embodiment presents a sloping aspect to the passing workpiece W.
  • end 32 slides down to the end of the workpiece W as it moves past, thereby eliminating element 18 dropping to a closure and abrupt impact of the seal edge 32 against the sealing plate 38 upon closure.
  • Additional advantage is gained from the overlapping relationship of the adjacent elements in that maintaining the overlap significantly, as illustrated at 34 increases the flow resistance to the atmosphere gases within the furnace and vestibule, thereby reducing the intensity from the gases to evacuate the chambers.
  • the overlap measures 1 /2" for a clearance of ,4 over a length of 18 /2" on side 22.
  • these dimension parameters provide additional preferred advantage in that the gas flow betweenelements in the overlap area is turbulent as opposed to laminar according to Reynolds criterion.
  • additional gas flow resistance is developed across the seal area further enhancing the seal effectiveness and the stability of the tapered furnace atmosphere.
  • the sealing elements would be installed in curtains 16 at both the entry and discharge ends of vestibule 4 and furnace 6, either singly or in multiple rows.
  • the lateral dimension of the individual element 18 formed by the distance between the sides 22 by partition 24 would be slightly larger than the width of the workpiece W passing into the furnace.
  • the elements of the illustrated installation measure 2 inches and accommodate bars of slightly less width. Charge material may also be bundled to a width closely approaching an integral multiple of element width. In actual practice, the seals have worked effectively for coiled material displacing several seal elements upon entry into the furnaces.
  • lift plates 40 affixed to shaft 15 and operable upon rotation of shaft 15 by crank 42, are positioned against element 1 8 when in a closed position. Rotation of crank 42 and shaft 15 will lift all elements 18, thus raising the curtain 16 and presenting up to a full opening to furnace vestibule 4 for those instances where decreased gas flow resistance or access is desired.
  • rod 15 is hollow and water cooled to maintain the shaft strength at the elevated temperatures encountered within the vestibule 4.
  • Apparatus for sealing an opening in a closed atmosphere chamber comprising: a plurality of individual elements having two parallel planar sides; a separator disposed between said planar sides joined thereto and having a dimension along said jointures at least as large as one dimension of said opening; mounting means adapting said elements for displacement in the direction of said two planar sides, said two sides having a dimension in the direction of displacement at least as large as said displacement and said individual elements being mounted in a side-by-side relationship having a planar side of one in juxtaposed relationship with the planar side of an adjacent element whereby said juxtaposed planar sides of adjacent elements maintain a continually overlapping relationship when one of said elements is displaced.
  • Apparatus according to claim 2 wherein the chamber is an annealing furnace and said mounting means adapting said elements for displacement in the direction of said planar sides includes pivotal mounting means whereby said displacement is rotational about said pivotal mounting means in the direction of said planar sides.
  • planar sides are substantially triangular in shape with said pivotal mounting means disposed at one corner of said triangle.
  • Apparatus according to claim 5 wherein said individual elements are adapted to be displaced by a workpiece progressing through said furnace.
  • Apparatus according to claim 8 wherein said elements are disposed in a plurality of rows.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Tunnel Furnaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Furnace Details (AREA)
US7721A 1970-02-02 1970-02-02 Furnace seal Expired - Lifetime US3606288A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US772170A 1970-02-02 1970-02-02

Publications (1)

Publication Number Publication Date
US3606288A true US3606288A (en) 1971-09-20

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ID=21727786

Family Applications (1)

Application Number Title Priority Date Filing Date
US7721A Expired - Lifetime US3606288A (en) 1970-02-02 1970-02-02 Furnace seal

Country Status (6)

Country Link
US (1) US3606288A (enrdf_load_stackoverflow)
JP (1) JPS5414255B1 (enrdf_load_stackoverflow)
CA (1) CA925895A (enrdf_load_stackoverflow)
DE (1) DE2104845A1 (enrdf_load_stackoverflow)
FR (1) FR2078094A5 (enrdf_load_stackoverflow)
GB (1) GB1317718A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4285668A (en) * 1979-10-03 1981-08-25 Pepe Robert D Pressurized gas seal for furnace atmosphere containment
US4653171A (en) * 1983-01-10 1987-03-31 Coble Gary L Refractory insulation mounting system and insulated structures
US4666404A (en) * 1985-07-29 1987-05-19 Suey Paul V Door for slab-heating furnace and the like
US4997364A (en) * 1988-02-22 1991-03-05 Radiant Technology Corporation Furnace assembly for reflowing solder on printed circuit boards
US5308046A (en) * 1983-01-10 1994-05-03 Coble Gary L Insulated furnace door system
US5483548A (en) * 1983-01-10 1996-01-09 Coble; Gary L. Insulated furnace door and wall panel system
US20090026654A1 (en) * 2006-01-19 2009-01-29 Asahi Glass Company Limited Molding apparatus and method for conveying conveyance object
US20100206203A1 (en) * 2007-05-21 2010-08-19 Mario Magaldi System for dry extracting/cooling heterogeneous material ashes with control of the air inlet in the combustion chamber

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2569261B1 (fr) * 1984-08-17 1987-04-17 Stein Heurtey Four muni d'un rideau propre a obturer l'ouverture de defournement
GB8428129D0 (en) * 1984-11-07 1984-12-12 Encomech Eng Services Heat retaining means
DE3916183A1 (de) * 1989-05-18 1990-11-22 Mahler Dienstleistung Tuer zum oeffnen und verschliessen einer oeffnung eines durchlaufofens
DE102010049837A1 (de) * 2010-10-27 2012-05-03 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Gasschleuse sowie Beschichtungsvorrichtung mit einer Gasschleuse
CN104099453B (zh) * 2014-07-30 2016-03-09 中冶南方(武汉)威仕工业炉有限公司 炉段气氛阻隔用密封挡板

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4285668A (en) * 1979-10-03 1981-08-25 Pepe Robert D Pressurized gas seal for furnace atmosphere containment
US4653171A (en) * 1983-01-10 1987-03-31 Coble Gary L Refractory insulation mounting system and insulated structures
US5308046A (en) * 1983-01-10 1994-05-03 Coble Gary L Insulated furnace door system
US5335897A (en) * 1983-01-10 1994-08-09 Coble Gary L Insulated furnace door system
US5483548A (en) * 1983-01-10 1996-01-09 Coble; Gary L. Insulated furnace door and wall panel system
US4666404A (en) * 1985-07-29 1987-05-19 Suey Paul V Door for slab-heating furnace and the like
US4997364A (en) * 1988-02-22 1991-03-05 Radiant Technology Corporation Furnace assembly for reflowing solder on printed circuit boards
US20090026654A1 (en) * 2006-01-19 2009-01-29 Asahi Glass Company Limited Molding apparatus and method for conveying conveyance object
US20100206203A1 (en) * 2007-05-21 2010-08-19 Mario Magaldi System for dry extracting/cooling heterogeneous material ashes with control of the air inlet in the combustion chamber

Also Published As

Publication number Publication date
JPS5414255B1 (enrdf_load_stackoverflow) 1979-06-06
FR2078094A5 (enrdf_load_stackoverflow) 1971-11-05
DE2104845A1 (de) 1971-08-26
GB1317718A (en) 1973-05-23
CA925895A (en) 1973-05-08

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Legal Events

Date Code Title Description
AS Assignment

Owner name: ALLEGHENY LUDLUM CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:ALLEGHENY LUDLUM STEEL CORPORATION;REEL/FRAME:004779/0642

Effective date: 19860805

AS Assignment

Owner name: PITTSBURGH NATIONAL BANK

Free format text: SECURITY INTEREST;ASSIGNOR:ALLEGHENY LUDLUM CORPORATION;REEL/FRAME:004855/0400

Effective date: 19861226

AS Assignment

Owner name: PITTSBURGH NATIONAL BANK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. RECORDED ON REEL 4855 FRAME 0400;ASSIGNOR:PITTSBURGH NATIONAL BANK;REEL/FRAME:005018/0050

Effective date: 19881129