US3735968A - Furnace - Google Patents

Furnace Download PDF

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Publication number
US3735968A
US3735968A US00161595A US3735968DA US3735968A US 3735968 A US3735968 A US 3735968A US 00161595 A US00161595 A US 00161595A US 3735968D A US3735968D A US 3735968DA US 3735968 A US3735968 A US 3735968A
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United States
Prior art keywords
pot
burners
burner
furnace
manifold
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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
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US00161595A
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English (en)
Inventor
M W Pearch
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.)
REX PRODUCTS Inc CHESTERLAND
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REX PRODUCTS Inc CHESTERLAND
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C99/00—Subject-matter not provided for in other groups of this subclass
    • 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
    • C21D1/34—Methods of heating
    • C21D1/44—Methods of heating in heat-treatment baths
    • 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
    • F27B14/00—Crucible or pot furnaces
    • 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
    • F27B14/00—Crucible or pot furnaces
    • F27B14/08—Details specially adapted for crucible or pot furnaces
    • F27B14/14—Arrangements of heating devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2700/00—Special arrangements for combustion apparatus using fluent fuel
    • F23C2700/04—Combustion apparatus using gaseous fuel
    • F23C2700/043—Combustion apparatus using gaseous fuel for surface combustion
    • 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
    • F27B14/00—Crucible or pot furnaces
    • F27B14/08—Details specially adapted for crucible or pot furnaces
    • F27B2014/0843—Lining or casing

Definitions

  • FURNACE BACKGROUND AND SUMMARY OF THE INVENTION Casting and heat treating operations require means for melting material and for holding sub- 4stantial quantities of molten or liquid material at elevated temperatures.
  • quantities of 500 pounds or more ofaluminum at temperatures of approximately l,200 F. or more must be maintained close to the desired temperature and readily available to the dies.
  • heat treating processes such as soaking, large quantities of salt bath at temperatures in the l,200 -l,300 F. range are necessary and must be maintained within close temperature limits.
  • furnaces are used for the heating and holding applications mentioned.
  • Such furnaces are generally fixed structures which include ponderous amounts of bulky refractory material.
  • ponderous amounts of bulky refractory material Although widely used heretofore, such furnaces have numerous disadvantages.
  • reverberatory-type furnaces the molten substance or heated liquid or pot containing the substance or liquid is exposed to direct flame and/or combustion products. Further, such furnaces typically are very noisy and provide an undesirable acoustic environment for persons required to attend to be in the neighborhood of such a furnace. Another disadvantage sometimes experienced is the non-uniform heating of the pot or crucible holding the material to be heated with attendant hot spots and shortened pot life.
  • This invention contemplates a furnace comprising a pot or crucible which is heated solely by a plurality of quite-operating, gas-fired infrared burners.
  • the burners are supported with their radiating surfaces facing and normally closely spaced from the wall of the pot or crucible. They can be arranged in any desired pattern and spacing from the pot wall and fuel and air input to each can be individually controlled to achieve the temperature distribution and balance desired and to accommodate the size and shape of a paritcular target area.
  • the burners are mounted in banks or arrays on movable supporting frames. Pre-mixed gaseous fuel and air is supplied to individualor individual sets of burner radiant elements from a distribution and supply manifold system, including a branch manifold associated with each frame-supported array of burners.
  • a distribution and supply manifold system including a branch manifold associated with each frame-supported array of burners.
  • the supporting frames are pivotally supported for swinging motion generally about one side thereof and toward and away from the walls of the pot.
  • each associated branch manifold and the distribution and supply manifold system preferably provides relative movement as required by the swinging motion of the burner supporting frame without leaking the gaseous fuel and air mixture it carries and permits the supported burners to be swung away from the pot and inspected, even while they are burning.
  • the burners preferably used in the furnace of this invention have limited and discreet areas of burning and radiating surface supplied with a mixture of gaseous fuel and air from underlying low pressure chambers substantially coextensive in area.
  • the low pressure chambers are separated from other and adjacent low pressure chambers.
  • Each low pressure chamber is supplied from a high pressure distribution manifold, preferably through an adjustable orifice.
  • the high pressure distribution manifold is positioned on the opposite side of the burner from the burning and radiating surface and away from the pot when the burners are in an operating position so that the distribution manifold is maintained as cool as possible.
  • the burners are preferably provided with radiating surfaces comprised of one or more refractory tiles such as, for example, tiles disclosed in U.S. Pat. No. 3,216,478.
  • the anti-backfiring properties of these tiles contribute to the safe operation of the furnace. Even in the event an unlikely backfiring or a burner element or of an inadvertent rupture of the radiating surface of a burner, however, the amount of gas readily available and near hot surfaces is minimized by the limited extent of the low pressure chamber and, thus, tends to reduce the possibility of any massive pre-ignition explosions.
  • the burners permit high heat transfer efficiency resulting in low exhaust temperature, reduced operating costs, and conservation of critical fuel.
  • the open side of the pot is shielded from the burners in such a way that there is no contamination of the molten bath due to exposure of combustion products, and no pollutl ants from the contents of the pot are carried away in the combustion products of the burners.
  • FIG. l is an overall perspective view of a furnace ernbodying this invention.
  • FIG. 2 is a perspective view of the furnace shown in FIG. l with parts of the cover or jacket removed or broken away;
  • FIG. 3 is another perspective view of the furnace shown in FIG. l with one of the sides of the burner supporting frame swung away from the side of the pot;
  • FIG. 4 is a transverse section through the furance of FIGS. l, 2, and 3, taken in the plane of line 4-4 in FIG. 2;
  • FIG. 5 is a partially sectioned perspective view of one of the burners comprising the arrays of burners in the furnace of FIGS. 1-4.
  • FIGS. 1, 2, and 3 similar views of a preferred ernbodiment of this invention, show a furnace with various of its elements covered and exposed and with its movable parts in different operating positions.
  • the central element of the furnace comprises a pot 10 made of any material suitable for withstanding the temperatures involved and for containing and holding the substance to be heated.
  • the pot is preferably of a shape having a high proportion of flat surfaces such as a parallelepiped. As shown in FIGS. 1-3, the pot has a generally rectangular and open upper face. Pot 10 is preferably longer than it is wide to provide two substantially parallel large-area flat surfaces.
  • pot shapes may be used, but, in high input applications especially, it is desirable for the greater enjoyment of the advantages of this invention to use a pot shape which provides a high ratio of pot surface area to volume.
  • Pot l is provided with an outwardly-turned edge or rim l2 at its upper perimeter which permits the pot to be suspended and supported in a simple frame structure 13.
  • the particular design of the frame forms no part of this invention. As shown, a simple structure of angles, channels, and tubes, and adapted to support the pot is suitable. Additional support may be provided by resting the bottom of the pot on refractory blocks, for example. This is especially desirable with low-strength crucibles.
  • Banks or arrays, indicated generally at B, of infrared gas burners 14 are arranged and positioned with their radiating surfaces directed toward and normally closely spaced from the large-area side surfaces l and 16 of the pot side walls. Obviously, the spacing may be varied with and adapted to the particular heat input requirements of each application.
  • the burners 14 are conveniently mounted in a movable frame 17 comprised of structural metal shapes. As shown in FIG. 2, frame 17 is substantially rectangular and holds five vertically aligned rows of burners 14. A corresponding frame 17 and set of burners 14 is located and similarly oriented on the opposite side 16 of the pot. Increased'heat input can be achieved by mounting sets of burners directed toward all sides and/or the bottom of the pot.
  • Pre-mixed quantities of gaseous fuel and air are delivered to burners 14 through a distribution and supply manifold system indicated generally at M.
  • This system comprises a large-diameter manifold 18 running across one end and near the bottom of the furnace.
  • the inlet end 19 of the manifold 18 is connected to a source of pre-mixed gaseous fuel and air (not shown).
  • a branch supply manifold 20 is provided on each side l5 and 16 of the furnace and pot and associated with the movable frames 17 and burners 14 supported thereon.
  • Each branch manifold is connected to the main manifold 18 through the movable joint 2l which permits rotation of branch manifold 20 about its axis with respect to manifold 18. even while mixtures of gaseous fuel and air are being carried by the manifolds and without any leaking of the mixture at the joint.
  • Branch manifolds 20 are preferably supported by and rest upon laterally extending arms 22.
  • Each vertical alignment of burners l4 contained on the frame 17 is supplied with gas from its associated branch manifold 20 from a plurality of longitudinally spaced outlets therein and connecting pipes 23.
  • Array B of burners 14 mounted in its movable frame 17 on each side of the furnace is able to be swung toward and away from the large-area flat surface sides 15 and 16 of pot 10 by pivotal swinging motion as a unit about is lower edge and substantially about the axis of its associated branch manifold 20.
  • one of the frame 17 supported burner arrays B is shown in its upright and operating position, held there, for example, by a simple swinging latch 24. In the position shown in FIG. 2, the burners lie in a substantially vertical plane closely spaced from and parallel to the side walls of the pot. This relationship is seen most clearly in the sectional view of FIG. 4.
  • array B of burners 14 and movable frame 17 is shown swung away from side wall 15 of pot 10 as permitted by movable connection 21 of branch manifold 20.
  • the burner arrays are preferably arranged so that they can be swung and moved toward and away from the side wall of th pot while they are in operation for easy inspection, maintenance, and repair. This is a unique feature of furnaces embodying this invention and contributes substantially to ease of operation and maintenance of the furnace.
  • pilot light assemblies 26 for lighting the burner arrays on opposite sides of the pot.
  • Pilot light assemblies 26 comprise gas supply pipes 27, shut-off valves 28, and ignition plugs 29. Any suitable ignition system may be employed and located as may be convenient and appropriate for the arrays and arrangement of arrays employed.
  • each vertical burner assembly shown in FIG. 2 consists of a single and a double tile burner head, bolted together to provide a total of three burner tiles in close proximity and in a row.
  • a reverberating screen overlies each burner tile.
  • each vertical row of burner housing consists of three burner tiles and overlying reverberator screens.
  • FIG. 5 is an enlarged perspective and partially sectioned view of a single burner unit 14.
  • the burner housing 40 comprises a casting having a shallow, openfaced, substantially square chamber 41 facing out one side. The open side of this chamber is closed with a radiant burner element 42 such as a refractory-type tile mentioned earlier.
  • a radiant burner element 42 such as a refractory-type tile mentioned earlier.
  • FIG. 5 a portion of such a tile is shown in place, suitably cemented or otherwise held against the supporting ledge 43 cast in the housing.
  • a small portion of reverberator screen 44 is diagrammatically indicated in FIG. 5 in a position overlying the outer surface of radiant burner element 42 and spaced a short distance therefrom.
  • Such screens are well known in the infrared gas burner art and, as such, form no part of this invention.
  • radiant burner element 42 The back side of radiant burner element 42 is exposed to and supplied with gaseous fuel and air mixture from shallow square chamber 4l behind it. Chamber 4l, in turn, is supplied through an adjustable regulating and distributing orifice 45 connecting it with a relatively large section distribution manifold 46.
  • Distribution manifold 46 is located on the opposite side of the burner head remote from the high temperature side and radiant burner 42.
  • the section of manifold 46 contained in each burner joins that of the adjacent section to form a continuous and generous distrib-.
  • each burner element 42 is discontinuous and separate from and unconnected with adjacent ones of such chambers.
  • the double burner element housing in fact, has two separate burner element chambers 41, each equal in area to the corresponding chamber in the single unit.
  • the amount of gaseous fuel and air mixture delivered from distribution manifold 46 of the burner heads to each individual burner 'element chamber 41 is controlled by a plate 47 movably adjustable toward and away from the counterbored entrance of orifice 45.
  • Plate 47 is mounted on the end of a threaded positioning element 48 extending, for convenience of adjustment, through and to the -outside of the bottom wall of distribution manifold 46 of each burner housing.
  • This invention is not limited to burners employing the particular means shown for controlling the amount of mixture delivered to the burner heads. If the application permits, one main control valve in the distribution manifold may be used'. Another convenient arrangement to control the amount of mixture delivered is the use of a split manifold system whose parts are separately controllable by means associated with each port.
  • a blanket of insulating material I preferably covers the outside suface areas of the pot not laterally adJacent the burner arrays B.
  • the movable burner banks are bordered by insulating material I which meets and provides a seal with the insulating material I lying around the pot.
  • the space between the burner faces and the outside surface of the pot is confined by the insulating material and vented through exhuast flue 49.
  • the burner arrays and frame supporting the pot are preferably enclosedin a sheet metal jacket, indicated generally at J.
  • the jacket portion overlying each burner array on opposite sides of the pot is removable to permit the lowering of the burner array to its position shownin FIG. 3.
  • Jacket J serves as a shield to keep persons from coming in contact with the heated burners and as a baffle to encourage the passage of cooling air upward and along the bottom side of the burners by convection.
  • burners might also be provided at the bottom and ends of the pot.
  • the two largearea burner arrays permit maintaining a thousand pounds of aluminum at about l,200 F.
  • the ends and the bottom, in general, and all areas of the pot not opposite a radiant burner surface are insulated against heat loss by insulating material indicated generally at I in the drawings.
  • each of said burners having a manifold chamber, a gas-pervious radiating element comprising a wall of said chamber, and an inlet port into said manifold chamber,
  • said pot supporting framework and said burner supporting frame having a low heat absorbing and a low heat insulating mass and capacity
  • a distribution and supply manifold system for supplying quantities of gaseous fuel and air to said burners, said system comprising a supply connection to each of said inlet ports of said plurality of burners,
  • said pot and its contents are heated and maintained at a desired temperature substantially only by direct infrared radiation on portions of the outer surface of said pot and a heat loss barrier of thermal insulating material adjacent the remaining portions of the outer surface of said pot.
  • said apparatus in which said pot has generally flat side surfaces and said plurality of burners includes an array of laterally adjacent burners ldirected at each of said generally flat side surfaces of said pot, said burners comprising each array having the radiating surfaces of their radiating elements facing the pot and all lying generally in a plane parallel to the surfaces faced.
  • said distribution and supply manifold system includes a branch manifold associated with and connected to each of said arrays of burners, and said arrays and associated branch manifolds-each being mounted on a movable tween to ccommodate the swinging motion of its associated burner array even during operation of the burners.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Combustion & Propulsion (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Combustion Of Fluid Fuel (AREA)
US00161595A 1971-07-12 1971-07-12 Furnace Expired - Lifetime US3735968A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US16159571A 1971-07-12 1971-07-12

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US3735968A true US3735968A (en) 1973-05-29

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US00161595A Expired - Lifetime US3735968A (en) 1971-07-12 1971-07-12 Furnace

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US (1) US3735968A (online.php)
JP (1) JPS5336973Y2 (online.php)
CA (1) CA970153A (online.php)
FR (1) FR2146015A5 (online.php)
GB (1) GB1387655A (online.php)
IT (1) IT964642B (online.php)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372356A (en) * 1966-01-18 1968-03-05 Fujitsu Ltd Compact relay with single yoke-core member
US4358095A (en) * 1980-12-05 1982-11-09 Debrey Andrew D Furnace
DE3909509A1 (de) * 1988-03-25 1989-10-12 Karmoy Winch As Schmelzofen

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9411489D0 (en) * 1994-06-08 1994-07-27 Morgan Crucible Co Furnace lining

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2191337A (en) * 1938-12-08 1940-02-20 Gen Electric Melting apparatus
US2262609A (en) * 1940-06-27 1941-11-11 Wean Engineering Co Inc Furnace for coating baths
US2615702A (en) * 1945-12-01 1952-10-28 Allert Berthold Industrial bath furnace
US3185461A (en) * 1963-08-01 1965-05-25 Nat Steel Corp Furnace construction
US3216478A (en) * 1962-04-13 1965-11-09 Electro Refractories & Abrasiv Radiant gas burner tile
US3407023A (en) * 1967-01-05 1968-10-22 Eclipse Fuel Eng Co Mounting for replaceable gas burner
US3422811A (en) * 1968-02-08 1969-01-21 Elmer E Strand High temperature surface-combustion radiant heater
US3521375A (en) * 1968-05-16 1970-07-21 Goodyear Tire & Rubber Dryer

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2191337A (en) * 1938-12-08 1940-02-20 Gen Electric Melting apparatus
US2262609A (en) * 1940-06-27 1941-11-11 Wean Engineering Co Inc Furnace for coating baths
US2615702A (en) * 1945-12-01 1952-10-28 Allert Berthold Industrial bath furnace
US3216478A (en) * 1962-04-13 1965-11-09 Electro Refractories & Abrasiv Radiant gas burner tile
US3185461A (en) * 1963-08-01 1965-05-25 Nat Steel Corp Furnace construction
US3407023A (en) * 1967-01-05 1968-10-22 Eclipse Fuel Eng Co Mounting for replaceable gas burner
US3422811A (en) * 1968-02-08 1969-01-21 Elmer E Strand High temperature surface-combustion radiant heater
US3521375A (en) * 1968-05-16 1970-07-21 Goodyear Tire & Rubber Dryer

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372356A (en) * 1966-01-18 1968-03-05 Fujitsu Ltd Compact relay with single yoke-core member
US4358095A (en) * 1980-12-05 1982-11-09 Debrey Andrew D Furnace
DE3909509A1 (de) * 1988-03-25 1989-10-12 Karmoy Winch As Schmelzofen

Also Published As

Publication number Publication date
IT964642B (it) 1974-01-31
JPS5336973Y2 (online.php) 1978-09-08
JPS52128605U (online.php) 1977-09-30
CA970153A (en) 1975-07-01
GB1387655A (en) 1975-03-19
FR2146015A5 (online.php) 1973-02-23
DE2233713B2 (de) 1976-08-05
DE2233713A1 (de) 1973-01-25

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