US3883295A

US3883295A - Rotary hearth furnace

Info

Publication number: US3883295A
Authority: US
Inventors: Ernest W Lowderman; Leland L Barrington; Jr Ferdinand Young
Original assignee: Armco Inc
Current assignee: Armco Inc
Priority date: 1972-10-16
Filing date: 1974-02-04
Publication date: 1975-05-13
Anticipated expiration: 1992-05-13

Abstract

A rotary hearth furnace comprising a single, unitary heating chamber the rotatable hearth of which is provided with a plurality of openings to receive turntables which are also rotatable, each turntable having a spindle to receive a coil or coils of rod. The furnace is provided with a charging station having a lift mechanism which is movable from a retracted position beneath the hearth into engagement with a properly positioned turntable so as to enable the turntable to be raised out of contact with the hearth framework so that a coil may be deposited on the turntable about the spindle without putting undue strain on the hearth framework. The lift mechanism is capable of raising the turntable high enough above the hearth so that, when desired, the mechanism which is used normally to charge the coil of rod onto the turntable may be used to remove the turntable from the furnace. The furnace is also provided with an unreeling station having both a lift mechanism and a turntable rotating mechanism, all of which is movable from a retracted position beneath the hearth to an elevated position so as to move a turntable from contact with the hearth framework so that the rotating mechanism may be actuated to rotate that turntable in either direction as desired. This lift mechanism may raise this turntable to a more elevated position to enable any debris collecting between the turntable and the heath to be cleared. An indexing mechanism is provided which moves the hearth and its turntables in a step by step fashion. Preferably the furnace is gas fired through burners located about the ceiling thereof.

Description

United States Patent 1m Lowderman et al.

[ ROTARY HEARTH FURNACE [75] Inventors: Ernest W. Lowderman,

Independence; Leland L. Barrington, Overland Park; Ferdinand Young, Jr., Independence, all of Mo.

[73] Assignee: Armco Steel Corporation,

Middletown, Ohio [22] Filed: Feb. 4, 1974 [2]] Appl. No.: 439,411

Related U.S. Application Data [62] Division of Ser. No. 297.886, Oct. 16, 1972, Pat. No.

Primary Examiner-John J. Camby Attorney, Agent. or Firm-Melville, Strasser, Foster & Hoffman [451 May 13,1975

[57] ABSTRACT A rotary hearth furnace comprising a single, unitary heating chamber the rotatable hearth of which is provided with a plurality of openings to receive turntables which are also rotatable, each turntable having a spindle to receive a coil or coils of rod. The furnace is provided with a charging station having a lift mechanism which is movable from a retracted position beneath the hearth into engagement with a properly positioned turntable so as to enable the turntable to be raised out of contact with the hearth framework so that a coil may be deposited on the turntable about the spindle without putting undue strain on the hearth framework. The lift mechanism is capable of raising the turntable high enough above the hearth so that, when desired. the mechanism which is used normally to charge the coil of rod onto the turntable may be used to remove the turntable from the furnace. The furnace is also provided with an unreeling station having both a lift mechanism and a turntable rotating mechanism, all of which is movable from a retracted position beneath the hearth to an elevated position so as to move a turntable from contact with the hearth framework so that the rotating mechanism may be actuated to rotate that turntable in either direction as desired. This lift mechanism may raise this turntable to a more elevated position to enable any debris collecting between the turntable and the heath to be cleared. An indexing mechanism is provided which moves the hearth and its turntables in a step by step fashion. Preferably the furnace is gas fired through burners located about the ceiling thereof.

16 Claims, 12 Drawing Figures PATENTED RAY I 31875 SHEET &0? 8

ROTARY HEARTH FURNACE CROSS REFERENCE TO RELATED APPLICATION This application is a division of copending application Ser. No. 297,886 filed Oct. 16, l972, in the names of the same inventors and entitled ROTARY HEARTH FURNACE AND SYSTEM FOR FORMING BALLS, now U.S. Pat. No. 3,827,267.

BACKGROUND OF THE INVENTION 1. Field of the Invention The furnace of this invention, although capable of many uses, has particular utility when used as a part of the system for feeding hot rod in a substantially continuous manner to forging apparatus for forging steel balls for use in grinding mills. A typical forging apparatus is shown in U.S. Pat. 3,239,912 and 3,478,556 to Baumgartner et al. The halls coming from such forging apparatus are then shaped into a substantially true sphere by a pancake sizer such as is shown in U.S. Pat. 3,621,692 to Weed.

The forging apparatus above noted is too fast to feed with hot bars if full and proper utilization of the apparatus is to be realized. It was determined, therefore, that best utilization of the forging apparatus could be achieved if hot coils could be used for feeding the apparatus. The rotary hearth furnace of this invention provides the means by which a succession of coils of rod may be properly heated and then fed almost continuously into the forging apparatus.

2. Description of the Prior Art Although a search of the prior art was conducted in an effort to locate those United States patents most pertinent to the development at hand, no assertion is made that the best such art was located, this, however, being the intent of the search; such search developed the following U.S. Pat. Nos: 3l0,402 Fox, 734,114 Beker, 1,903,909 Cope, 2,413,228 Hepburn, 2,401,930 Hansen, 201,582 Wilmsmann, 373,463 Lenox, 444,55! Daniels, and l,l 18,869 Kugel.

Fox discloses a rotary annealing cylinder with a plurality of rotatable annealing boxes thereon. Beker discloses a furnace having a plurality of individual, separately heated, heating chambers, each chamber having a single rotatable support for a coil of rod. Cope discloses a rotary hearth with a plurality of containers for holding material to be treated, each container, however, being non-rotatable. Hepburn discloses a furnace the lower half of which, carrying fixed retorts, rotates. Hansen discloses step by step rotation of a carrier having a plurality of rotating heads thereon. The remaining patents developed by the search do not seem to be of particular significance.

SUMMARY OF THE INVENTION The furnace of this invention is a part of a system which enables optimum use of the forging and sizing apparatus above identified so that a succession of steel balls may be formed almost continuously from coiled rod of suitable material. The furnace comprises a sin gle, unitary heating compartment completely lined with refractory material. The refractory material comprising the furnace hearth is supported by suitable framework. A plurality of evenly spaced openings are provided in the hearth and each such opening is provided with a turntable which rests within the opening, out of contact with the hearth but supported on portions of that framework which also supports the hearth. Each such turntable is provided with a spindle about which one or more coils of rod may be deposited.

Operation may begin with a first turntable being lo cated in charging position, the furnace door being opened and a coil of rod being deposited on the so located turntable by the charger which is in turn fed by a suitable coil conveyor. The hearth is indexed so that the first turntable so charged is eventually brought to the unreeling station. In the meantime, other coils of rod are placed on the various turntables when positioned before the charger. The timing will be such that by the time the first coil travels from the charging station to the unreeling station, it will be hot enough to be fed into the forging apparatus. Each succeeding coil will also be sufficiently heated by the time it is fed into such forging apparatus, the hearth having been indexed the required number of times to bring such succeeding coil into position for unreeling into the forging apparatus.

The grinding ball sizer is in line with the forging apparatus to finish the shaping of the balls. The rotary hearth is continually indexed and the operation proceeds as stated above. New coils are loaded on an empty turntable at the loading or charging station while a feeding or unreeling operation is taking place.

The turntable positions at the charging-loading and feeding-unreeling stations have power means which rise to engage the turntablesv At the charging station there is two position lifting, the first position being to stabilize the turntable and remove it from contact with the hearth frame structure while the coil of rod is deposited on such turntable, and the second position is to lift the turntable even higher so that the one piece spindle-turntable can be replaced when necessary. At the unreeling station, the power means lifts to engage the turntable then in position and to effect a rotating action to feed the coil to the operator who then feeds the coil into the forging apparatus. The power to rotate the turntable is disengaged once the coil is fed into the forging apparatus as this latter apparatus will then pull the coil itself. The turntable power means can act as a slight drag on the coil to create a small amount of desired back tension. The power means may also be actuated to lift the turntable to a higher position to enable debris to be cleaned from between such table and the hearth proper.

The furnace is gas fired by a plurality of jets evenly disposed about the ceiling of the furnace. The furnace chamber is evenly heated to desired temperature by these jets and there are no internal partitions separating the turntables and the coils of rod located thereon one from another. The gas fired furnace normally operates slightly above atmospheric pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic plan view of the rotary hearth furnace and system for forming balls from coils of suitable rod material.

FIG. 2 is a cutaway perspective view of the rotary hearth furnace of this invention.

FIG. 3 is a sectional view taken along the line 33 of FIG. 1.

FIG. 4 is a diagrammatic plan view indicating the position of the furnace hearth supports and of the indexing mechanism.

FIG. 5 is an enlarged elevational view, partly in section and partly broken away, taken on the line 5-5 of FIG. 4.

FIGS. 6, 7 and 8 are elevational views of the power means which engages the turntable when positioned at the unreeling station.

FIGS. 9, l0 and 11 are elevational views of the power means for engaging a turntable when positioned at the charging station.

FIG. 12 is an enlarged sectional view taken on the line 12-12 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, the rotary hearth furnace and system for forming balls is generally illustrated. The rotary hearth furnace is indicated at 20, the coil loader at 21, the coil conveyor at 22, the forging apparatus at 23, the grinding ball sizer at 24 and the mechanical and gravity conveyors for removing the finished balls to storage and the like at 25a and 25b. The forging apparatus may be like that shown in the Baumgartner et al U.S. Pat. Nos. 3,239,912 and 3,478,556 and, therefore, will not be described in greater detail here. Similarly, the grinding ball sizer 24 may be like that shown in the patent to Weed U.S. Pat. No. 3,621,692 and further description will not be set forth herein. A turntable 26a and a ball conveyor 26b transfer the forged balls from the forging apparatus 23 to the finishing sizer 24. The coil conveyor 22 delivers coils of cold rod to the charger 27 which periodically deposits one or more coils of rod on a turntable positioned at the charging station. For purposes of illustration the center of the charging station is indicated at 28 and the center of the unreeling station at 29.

In FIG. 1 the rotary hearth furnace is seen in top plan with the plumbing removed. Ten turntables 30 having spindles 31 are uniformly disposed about the furnace hearth. No coil of rod has yet been placed on the turntable 30 which is at the charging station 28. A coil of rod 32 is on that turntable 30 which is located at the unreeling station 29. Normally there will be no coil of rod on the single turntable located between the unreeling station 29 and charging station 28, noting that rotation of the hearth is in a counterclockwise direction as viewed in this FIG. 1. The remaining seven turntables 30 are all shown as having a coil of rod 32 mounted thereon.

The pairs of openings 33a and 33b schematically represent the gas fired jets by which the interior of the furnace is heated, these jets being located in the ceiling of the furnace, discharging thereinto, and being suitably fed with conventional gases through conventional plumbing (not shown) as will be understood by those skilled in the art. Although a pair of such burners 33a and 33b may be positioned for each of the ten turntables, it may be desirable to omit one or more of these at that position wherein the turntable is normally empty, that being the position to which the hearth is indexed immediately after a coil of rod has been unreeled from the station 29 and fed into the forging apparatus 23.

Coils of rod of suitable material are placed on the coil loader 2] and thereby transferred to the coil conveyor 22. This conveyor is designed to lift the coil, actually a succession of coils, and move it to the charger 27, thereafter lowering to thereby deposit the coil on such charger. The charger is designed to move into the charging station 28 and deposit the coil on that turntable 30 then positioned there, about the spindle 31. The furnace door 34 is located at this charging station and will, of course, be raised before the coil is charged into the furnace. After the charger 27 retracts, the door 34 will be closed, and the indexing mechanism will bring the next turntable into position, the hearth being moved in a counterclockwise direction, as viewed in FIG. 1, to accomplish this. By the time the first coil charged into the furnace reaches the unreeling station 29, nine of the ten turntables will carry such coils, that coil located at the unreeling station now being properly heated and ready for feeding into the forging apparatus 23. This latter step is accomplished by an operator, aided by mechanism to be described, grabbing an end of the coil with suitable tongs and feeding it to the known receiving mechanism of the forging apparatus 23. This forging apparatus will pull the hot coil of rod therethrough, forming grinding balls which are then transferred by turntable 26a and conveyor 26b to the grinding ball sizer 24 which will finish them and send them on their way to storage by means of the mechanical conveyor 25a and the gravity conveyor 25b. As soon as the first turntable to reach the unreeling station is relieved of its coiled rod in this manner, the hearth will be indexed to bring the next turntable into position for immediate feeding of its coiled rod to the forging apparatus 23 while an additional coil is placed on the previously empty turntable 30 when moved into position before the charger 27. This operation will continue in this manner so long as it is desired to manufacture finished grinding balls.

Referring now to FIGS. 2, 3, 4 and 12, certain of the features of the rotary hearth furnace 20 will be described in greater detail. As is indicated in these figures, the walls 35, including also the ceiling and the rotary hearth or floor 36, are made of or lined with refractory material, as will be understood by those skilled in the art. With respect to the hearth 36, it includes a steel plate 37 attached to suitable frame members generally indicated at 38. As perhaps best seen in FIGS. 3 and 12, the frame structure 37-38 includes a first, annular outer rail 39 attached thereto and from which depends a second, annular outer rail 40 having a member 41 which engages a plurality of rollers 42 suitably supported in bearings 43 disposed on a building floor beneath the hearth 36. Similarly, there is a first annular inner rail 44 fixed to the frame structure 37-38 and a second annular, inner rail 45 depending from the rail 44 and having a member 46 resting on a plurality of rollers 47 suitably supported in bearings 48 placed about the building floor beneath the hearth. In this manner the reinforced hearth 36 is supported on the plurality of

rollers

42 and 47.

FIG. 4 diagrammatically represents more detail respecting the location of the rollers and

bearings

42, 43 and 47, 48. These support rollers or wheels 42 are designed to be engaged by the rail members or outer tracks 39-41 while the support rollers or wheels 47 are designed to be engaged by the inner rail or track members 44-46. Also spaced about the underside of the hearth frame structure are a plurality of

track stabilizing wheels

49 and 50 for the outer and inner tracks respectively. The unreeling pit, in which the lifting mechanism, to be described, is located is shown at 290 in FIG. 4, and the charging pit for housing its lifting mechanism, to be described, is indicated at 2821. A plurality of frame members 51 are diagrammatically shown in FIG. 4 as constituting a part of the understructure supporting the plate 37 and hearth 36. The indexing means, to be described in detail in connection with the description of FIG. 5, is generally indicated at 52 in FIG. 4. A circular indexing rail will be fastened to the underside of the hearth frame structure, as will be described in connection with FIG. 5.

Referring now to FIGS. 2 and 3, other features of the rotary hearth construction will be described. The right hand side of FIG. 3 depicts a portion of the charging station 28 while the left hand side of FIG. 3 depicts a portion of the unreeling station 29. The lift mechanisms for both stations have been omitted; these are shown, and will be described later, in FIGS. 9 through I] and 6 through 8 respectively. The turntables 30 normally rest on the frame structure 37-43, 44-48 and various of the web members 51. Openings 53, therefore, are provided in the hearth 36 and these openings are of greater diameter than those of the turntables 30. This insures that, even in the down position wherein the turntable is resting on the frame structure, the turntables 30 will not be in direct contact with the hearth 36. This prevents damage to the hearth and to the turntables which might otherwise occur should the refractory materials of which each is made come into contact with one another. The turntable 30 at the charging station 28, as shown in FIG. 3, is in its normal, down position wherein it is resting on the frame structure while the turntable 30 at the unreeling station 29 is shown, in FIG. 3, in its unreeling position wherein it has been lifted, by mechanism to be described but not shown in FIG. 3, off the frame structure.

Referring now to FIG. 5, the indexing mechanism for rotating the hearth 36 will be described. This mecha nism 52 includes brace structure 54 mounted on the building floor. Connected to the structure 54 is a piston-cylinder arrangement 55. Pivotally connected to the piston-cylinder arrangement 55, as indicated at 56, is a carriage 57 having a spring biased dog 58 mounted thereon. The dog 58 is normally biased to the position shown in FIG. 5. An indexing rail 59 having flanges 60 is suitably secured to the frame understructure generally indicated at 38a. The carriage 57 is supported from this indexing rail 59 by pairs of rollers 61 and 62 which ride on the flanges 60 on either side of the rail 59. These rollers 61 and rollers 62 are mounted on bracket members 63 and 64, respectively, connected to the carriage 57. The underside of the rail is provided with a series of dogs 65 spaced completely around the hearth. The dogs 65 are arranged to be engaged by the carriage dog 58.

Upon actuation of the piston-cylinder arrangement 55, by control means not shown, but in such manner as will be readily understood to those skilled in the art, the carriage 57 advances and the dog 58 engages a dog 65 whereby the frame structure and hearth will be moved the length of the piston stroke. When the piston is retracted, the dog 58, being spring biased, will pass beneath the next dog 65 to the rear of that initally en gaged whereupon further actuation of the piston will result in the dog 58 engaging such next dog 65 to again advance the hearth. Depending on the size of the furnace, the number of turntables and similar dimensions of the piston cylinder and spacing of the various dogs, one or more actuations of the piston-cylinder 55 may be required to index the hearth so as to move the various turntables from one position to the next.

Turning again to FIG. 12, mechanical means are illustrated for sealing the rotary hearth furnace. As shown, an L-shaped bracket 66 is secured to the frame structure 38. A similar L-shapcd bracket 67 having an upturned portion 68 is secured to the stationary furnace wall 35 as indicated at 69. A .l-shaped member 70 has a downwardly turned portion 71 which hooks over the upturned portion 68 of the member 67. As the hearth 36 is indexed within the confines of the stationary furnace wall 35 by the mechanism described in connection with FIG. 5 and generally indicated in FIG. 4, the member 66 will slide along the members 70 whose hinging action from fulcrums at 68 permits movement to allow for heat expansion and the escape of debris, especially scale. Also of importance is that the furnace is sealed from undue loss of heat.

FIGS. 6, 7 and 8 disclose lift mechanism generally indicated at 72 for the turntable 30 when located at the unreeling station 29.

This mechanism includes a supporting platform 73 having an upstanding nose 74 located centrally thereof. This nose is designed to register within a corresponding opening located in the center of the lower part of each of the turntables 30, such an opening being indicated at 75 in the left hand side of FIG. 3. The platform 73 rests on bearings 76 located on a member 77 which is supported from a first table member 78 by a plurality of braces 79. Suitably supported from the first table member 78 is a reversible motor 80 the output end of which is connected by a belt or chain and sprockets 81 to suitable pulley mechanism 82. This mechanism drives, by conventional means not shown but generally located within the housing 83, a shaft 84 connected to the platform 73. Actuation of the motor 80 may rotate the platform 73 in either direction as desired.

The mechanism 72 includes a first set of cylinders 85 having pistons 86 movable therein by conventional means, as will be understood by those skilled in the art. A second table member 87 is secured to the ends of the pistons 86. A second set of cylinders 85a is secured to the bottom of the table member 87 and is provided with pistons 88 which are connected to the first table member 78.

The platform 73 and associated mechanism is shown in its retracted position in FIG. 6 at which time it will be understood that the mechanism 73-74 is beneath and out of the way of the frame structure connected to the underside of the hearth 36. The lift mechanism 72 is designed to permit upward movement of the platform 73 by successive increments to two positions. When the pistons 86 are actuated, the tables 78 and 87 are moved to a first position wherein the platform passes upwardly through the hearth frame structure, through the open ing 53 of the hearth floor 36 and into contact with the underside structure of that turntable 30 then located within the unreeling station 29 so as to move the turntable off of the hearth frame structure a short distance. The turntable 30 and coil 32 (see FIG. 2) of rod material will then be supported solely by the platform 73 and the related mechanism generally indicated at 72. At this first position it is possible to rotate the platform 73 in either direction by actuation of the reversible motor 80. This will enable an operator to so position the coil 32 that he can grab the end thereof by a pair of tongs inserted through a small door so as to pull the end out of the furnace and into the forging apparatus 23. After the end of the rod 32 is engaged within the forging apparatus 23, clutch mechanism, not shown, for the motor mechanism 8084 may be released whereafter such turntable power means 80-84 may be used as a slight drag on the coil to create a small amount of desired back tension as the coil is fed into the forging apparatus. The position of the tables 78 and 87 after upward extension of the pistons 86 is illustrated in FIG. 7. At this point the nose 74 has engaged within the opening 75 and the turntable 30 is supported on platform 73.

At times it may be necessary to clear debris which may collect between a turntable 30 and the hearth. This can be accomplished by the upward extension of pistons 88 which raise plate 78 above plate 87. Raising plate 78 results in the lifting of support platform 73 and a turntable 30 to a higher position. This higher, up position can be reached only after an initial up position is established by pistons 86 as indicated in FIG. 7. Any debris collecting within the furnace may be removed therefrom via the now more greatly exposed opening 53. This is the condition illustrated in FIG. 8. When it is time to index another coil of rod into position to be unreeled into the forging apparatus, the platform 73 and related mechanism are first returned to the retracted position of FIG. 6 wherein it will be out of the way of the frame structure connected to the bottom of the hearth 36. The hearth is then indexed into such position that another coil of rod is placed within the unreeling station and another, now empty, turntable is positioned within the charging station.

The lift mechanism for the charging station 28 is generally indicated at 90 in FIGS. 9, and 11. This mechanism includes a support platform 91 having a centering nose 92 designed to engage within the opening 75 provided in the bottom of the turntable 30 and related structure. The mechanism 90 includes a first set of cylinders 93 having pistons 94 and a second set of cylinders 95 having pistons 96. The second set of cylinders 95 is connected to frame structure 97 which is in turn connected to the ends of the pistons 94.

The lift mechanism 90 is shown in FIG. 9 in its retracted position at which time the platform 91 and centering means 92 are beneath and out of the way of the frame structure supporting the hearth. When a coil of rod is to be charged onto a turntable located at the charging station 28, the pistons 94 are actuated so as to bring the platform 91 to the position indicated in FIG. 10. In this figure it will be understood that the platform 91 has engaged the bottom of a turntable 30 and has lifted the turntable from its original position of support on the hearth frame structure. This first position shown in FIG. 10 is to stabilize the turntable and to relieve the hearth frame structure from the shock that occurs when a coil of rod is deposited on a turntable.

Sometimes it becomes necessary to remove a turntable from the furnace so as to repair it or replace it with another turntable. By raising the turntable above the position shown in FIG. 10, the same mechanism which deposits a coil on the turntable may be used to engage beneath the turntable and thereby remove it from the furnace; this is the position shown in FIG. 11. Thus when the pistons 96 are actuated, the support platform 91 is moved further upwardly so that the charger 27 may be actuated to withdraw the turntable 30 from the furnace. The mechanism is returned to the retracted position of FIG. 9 before the hearth 36 is indexed again.

The construction of a turntable 30 is similar to that of the hearth 36 in that there may be a bottom plate 98 secured beneath the refractory material and above the rail-frame supports 99, see FIG. 3. Also, it will be obvious that the lift mechanisms 72 and of FIGS. 6 through 8 and 9 through 11, respectively, will be positioned at the unreeling and charging

stations

29 and 28, respectively, as generally indicated in FIG. 2.

It is believed that the foregoing constitutes a complete description of the rotary hearth furnace and the system for forming balls of which it is a part. It will be apparent to those skilled in the art, however, that modifications may be made in the furnace and system without departing from the scope and spirit of the invention as set forth herein.

Although the furnace and system have been de scribed with reference to particular structures and ar' rangements, such structures and arrangements are not to constitute a limitation on the invention as claimed except insofar as such structures and arrangements are specifically set forth in the subjoined claims.

In a typical rotary hearth furnace constructed according to this invention 10 combination spindleturntables may be spaced around the main rotary hearth. This hearth, for example, may have a diameter of 27 feet with the spaced turntables each having a diameter of 5 feet. Each turntable may hold up to 2500 lbs of coil. The total weight on a single turntable does not have to be all in one coil; two 900 lb. coils, for example, could be placed on each turntable. In the case of two-coil feeding, the operation would begin with a first turntable in the rotary hearth being indexed to the unreeling station for feeding the forging apparatus. The first coil would be fed into the forging apparatus and the second coil immediately afterwards. The hearth is then promptly indexed again and the operation repeated. New coils may be loaded on an empty turntable at the loading station while a feeding operation takes place.

In the operation above described, continuous production is dependent upon having sufficient capacity for heating a particular rod size. It is believed that changes in furnace dimension or burner size, which could adjust the heating capacity to adapt to a different rod size, do not alter the scope and/or spirit of this invention. In any case, the furnace of this invention makes possible a rate of feeding the forging apparatus and, therefore, the production of grinding balls, at high speeds not previously obtainable.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

I. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindleturntable within each said opening and clear of said hearth, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntables so as to move a coil through substantially all of said chamber from said charging station to said unreeling station.

2. The furnace of claim 1 in which a sealing means is provided between the outer edge of said rotary hearth and the wall of said chamber.

3. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindleturntable within each said opening, each said spindleturntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamher; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a lift mechanism for said charging station, said lift mechanism being located beneath said chamber and arranged to register with said openings as said hearth is rotated by said indexing means, said lift mechanism having a retracted position out of the way of said frame work, said lift mechanism having a support platform capable of passing through said frame work and a said opening to engage a said spindle-turntable, and means to actuate said lift mechanism so as to engage said platform with a said spindleturntable and lift same from said frame work to a first position, whereby a said coil may be placed on said so lifted spindle-turntable without shock to said frame work.

4. The furnace of claim 3 in which said actuating means may move said platform and spindle-turntable to a second position whereby to enable the removal of said spindle-turntable from said chamber.

5. The furnace of claim 3 in which said platform has a centering means thereon to register with a mating portion provided in the under side of a said spindleturntable.

6. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindleturntable within each said opening, each said spindleturntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a rotary lift mechanism for said unreeling station, said rotary lift mechanism being located beneath said chamber and arranged to register with said openings as said hearth is rotated by said indexing means, said rotary lift mechanism having a retracted position out of the way of said frame work, said rotary lift mechanism having a support means capable of passing through said frame work and a said opening to engage a said spindle-turntable, spindleturntable rotating means connected to said support means, means to actuate said rotary lift mechanism so as to engage said support means with a said spindleturntable and lift same from said frame work to a first position, and means to actuate said rotating means so as to rotate said support means when in said first position.

7. The furnace of claim 6 in which said means to actuate said rotary lift mechanism may move said support means and spindle-turntable to a second position to ef feet a greater clearance between the spindle-turntable and said hearth whereby to enable debris to be removed from said chamber through a said opening.

8. The furnace of claim 6 in which said support means has a centering means thereon to register with a mating portion provided in the under side of a said spindle-turntable.

9. The furnace of claim 1 including brace members fixed to the underside of said hearth, and said frame work including an inner circular rail and an outer circular rail and cross members engaging both of said rails, and means depending from said rails and engaging said bearing means, said bearing means comprising rollers mounted on a building floor, said hearth comprising refractory material mounted on said brace members engaging said rails and said cross members.

10. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindleturntable within each said opening, each said spindleturntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamher; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and in which said indexing means comprises a piston-cylinder arrangement fixed to a building floor, a carriage pivotally connected to the piston, a spring biased dog protruding upwardly from said carriage, a circular indexing rail fixed to said frame work, said indexing rail being provided with fixed dogs protruding downwardly therefrom, and means to slidingly connect said carriage to said rail so that said spring biased dog will engage said fixed dogs, whereby movement of the piston in one direction will effect engagement of said spring biased dog with a said fixed dog so as to move said hearth a given increment and move ment of said piston in the opposite direction will result in said spring biased dog passing beneath the next fixed dog so as to be in position to engage this last mentioned dog upon next actuation of the piston.

11. The furnace of claim 1 in which a said spindleturntable comprises refractory material having a plate fixed to the underside thereof, and brace members fixed to said plate.

12. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindleturntable within each said opening, each said spindleturntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamher; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a sealing means provided between the outer edge of said rotary hearth and the wall of said chamber; said sealing means comprising a circular channel member mounted on one of said wall and said hearth and a circular rim mounted on the other of said wall and said hearth and engaged within said channel member.

13. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle turntable within each said opening, each said spindleturntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a sealing means provided between the outer edge of said rotary hearth and the wall of said chamber; said sealing means comprising a first L-shaped bracket fixed to said hearth, a second L-shaped bracket fixed to said chamber wall, and a J shaped member swingably hanging from said second L-shaped bracket and adapted to abut said first L- shaped bracket, whereby temperature of said furnace is maintained while allowing debris and scale to escape.

14. The furnace of claim 1 in which said openings are evenly spaced about said hearth, the spacing being such that when one said opening is at the said charging station and another of said openings is at the said unreeling station there will be only one opening located between those sides of said stations which are closest together and a plurality of openings between those sides of said stations which are farthest apart.

15. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber lined with refractory material; a circular, rotary hearth for said chamber, said hearth comprising a plate having refractory material located thereon, first brace members fixed to the underside of said plate, said plate and material having a plurality of evenly spaced, circular openings located therethrough between said first brace members and disposed in circular fashion; a circular spindle-turntable within each said opening out of contact with said hearth, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber, each said spindleturntable comprising a plate with refractory material thereon and second brace members fixed to the underside of said plate; frame work comprising an annular inner rail and an annular outer rail and cross members joining said rails, and means depending from said rails and engaging rollers mounted on a building floor; said hearth and said spindle-turntables resting on said frame work; a charging station for said chamber, lift mechanism having a platform normally retracted beneath said station and adapted to be moved through said frame work and a said opening to engage a spindle-turntable and move it from engagement with said frame work, and actuating means to move said platform into engagement with a said spindle-turntable to lift it from said frame work whereby a said coil may be placed thereon without shock to said frame work; an unreeling station for said chamber, rotary and lift mechanism having a support means normally retracted beneath said unreeling station and adapted to be moved through said frame work and a said opening to engage a spindleturntable and move it from engagement with said frame work, second actuating means to move said support means into engagement with a said spindle-turntable to lift it from said frame work, and rotating means to rotate said support means when in its last mentioned position; and indexing means for moving said frame work, hearth and turntables so as to move a said coil from said charging station, through substantially all of said chamber, to said unreeling station, said indexing means including an annular indexing rail fixed to said frame work, said indexing rail having a series of evenly spaced dogs depending therefrom throughout, and pistoncylinder means mounted on the building floor and having a carriage adapted to move along said indexing rail, said carriage having a member to engage successive of said dogs upon reciprocation of the piston-cylinder means whereby to move said frame work in step by step fashion,

16. A gas fired furnace comprising a single, unitary cylindrical heating chamber; a rotatable, circular hearth for said chamber; a plurality of spindleturntables evenly spaced throughout said hearth and clear thereof; means to rotate said hearth; and selective means to engage a said spindle-turntable when said hearth has been rotated to bring such turntable to said selective means, whereby a said spindle-turntable may be raised with respect to said hearth.

Claims

1. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening and clear of said hearth, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntables so as to move a coil through substantially all of said chamber from said charging station to said unreeling station.

3. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a lift mechanism for said charging station, said lift mechanism being located beneath said chamber and arranged to register with said openings as said hearth is rotated by said indexing means, said lift mechanism having a retracted position out of the way of said frame work, said lift mechanism having a support platform capable of passing through said frame work and a said opening to engage a said spindle-turntable, and means to actuate said lift mechanism so as to engage said platform with a said spindle-turntable and lift same from said frame work to a first position, whereby a said coil may be placed on said so lifted spindle-turntable without shock to said frame work.

5. The furnace of claim 3 in which said platform has a centering means thereon to register with a mating portion provided in the under side of a said spindle-turntable.

6. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a rotary lift mechanism for said unreeling station, said rotary lift mechanism being located beneath said chamber and arranged to register with said openings as said hearth is rotated by said indexing means, said rotary lift mechanism having a retracted position out of the way of said frame work, said rotary lift mechanism having a support means capable of passing through said frame work and a said opening to engage a said spindle-turntable, spindle-turntable rotating means connected to said support means, means to actuate said rotary lift mechanism so as to engage said support means with a said spindle-turntable and lift same from said frame work to a first position, and means to actuate said rotating means so as to rotate said support means when in said first position.

7. The furnace of claim 6 in which said means to actuate said rotary lift mechanism may move said support means and spindle-turntable to a second position to effect a greater clearance between the spindle-turntable and said hearth whereby to enable debris to be removed from said chamber through a said opening.

10. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and in which said indexing means comprises a piston-cylinder arrangement fixed to a building floor, a carriage pivotally connected to the piston, a spring biased dog protruding upwardly from said carriage, a circular indexing rail fixed to said frame work, said indexing rail being provided with fixed dogs protruding downwardly therefrom, and means to sliDingly connect said carriage to said rail so that said spring biased dog will engage said fixed dogs, whereby movement of the piston in one direction will effect engagement of said spring biased dog with a said fixed dog so as to move said hearth a given increment and movement of said piston in the opposite direction will result in said spring biased dog passing beneath the next fixed dog so as to be in position to engage this last mentioned dog upon next actuation of the piston.

11. The furnace of claim 1 in which a said spindle-turntable comprises refractory material having a plate fixed to the underside thereof, and brace members fixed to said plate.

12. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a sealing means provided between the outer edge of said rotary hearth and the wall of said chamber; said sealing means comprising a circular channel member mounted on one of said wall and said hearth and a circular rim mounted on the other of said wall and said hearth and engaged within said channel member.

13. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber; a rotary hearth for said chamber, said hearth having a plurality of openings therein; a spindle-turntable within each said opening, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber; frame work located beneath said hearth so as to support same, each said spindle-turntable also resting on said frame work; bearing means on which said frame work is engaged for purposes of rotation; a charging station for said chamber; an unreeling station for said chamber; and indexing means for moving said frame work, hearth and spindle-turntable so as to move a coil through substantially all of said chamber from said charging station to said unreeling station; and including a sealing means provided between the outer edge of said rotary hearth and the wall of said chamber; said sealing means comprising a first L-shaped bracket fixed to said hearth, a second L-shaped bracket fixed to said chamber wall, and a J-shaped member swingably hanging from said second L-shaped bracket and adapted to abut said first L-shaped bracket, whereby temperature of said furnace is maintained while allowing debris and scale to escape.

15. A furnace for heating a plurality of coils of rod; said furnace having a single, unitary gas fired heating chamber lined with refractory material; a circular, rotary hearth for said chamber, said hearth comprising a plate having refractory material located thereon, first brace members fixed to the underside of said plate, said plate and material having a plurality of evenly spaced, circular openings located therethrough between said first brace members and disposed in circuLar fashion; a circular spindle-turntable within each said opening out of contact with said hearth, each said spindle-turntable being adapted to receive at least one coil of rod to be heated within said chamber, each said spindle-turntable comprising a plate with refractory material thereon and second brace members fixed to the underside of said plate; frame work comprising an annular inner rail and an annular outer rail and cross members joining said rails, and means depending from said rails and engaging rollers mounted on a building floor; said hearth and said spindle-turntables resting on said frame work; a charging station for said chamber, lift mechanism having a platform normally retracted beneath said station and adapted to be moved through said frame work and a said opening to engage a spindle-turntable and move it from engagement with said frame work, and actuating means to move said platform into engagement with a said spindle-turntable to lift it from said frame work whereby a said coil may be placed thereon without shock to said frame work; an unreeling station for said chamber, rotary and lift mechanism having a support means normally retracted beneath said unreeling station and adapted to be moved through said frame work and a said opening to engage a spindle-turntable and move it from engagement with said frame work, second actuating means to move said support means into engagement with a said spindle-turntable to lift it from said frame work, and rotating means to rotate said support means when in its last mentioned position; and indexing means for moving said frame work, hearth and turntables so as to move a said coil from said charging station, through substantially all of said chamber, to said unreeling station, said indexing means including an annular indexing rail fixed to said frame work, said indexing rail having a series of evenly spaced dogs depending therefrom throughout, and piston-cylinder means mounted on the building floor and having a carriage adapted to move along said indexing rail, said carriage having a member to engage successive of said dogs upon reciprocation of the piston-cylinder means whereby to move said frame work in step by step fashion.

16. A gas fired furnace comprising a single, unitary cylindrical heating chamber; a rotatable, circular hearth for said chamber; a plurality of spindle-turntables evenly spaced throughout said hearth and clear thereof; means to rotate said hearth; and selective means to engage a said spindle-turntable when said hearth has been rotated to bring such turntable to said selective means, whereby a said spindle-turntable may be raised with respect to said hearth.