US3119606A

US3119606A - Intermediate mill reheating and processing furnace

Info

Publication number: US3119606A
Application number: US176343A
Authority: US
Inventors: Suydam Walter; Alfred S Sobek
Original assignee: Loftus Engineering Corp
Current assignee: Loftus Engineering Corp
Priority date: 1962-02-28
Filing date: 1962-02-28
Publication date: 1964-01-28
Anticipated expiration: 1981-01-28

Description

Jan. 28, 1964 w. sUYDAM ETAL 3,119,606

INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE Filed Feb. 28, 1962 6 Sheets-SheefI 1 ATTORN EYS Jan. 28, 1964 w. suYDAM ETAL INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE 6 Sheets-Sheet 2 Filed Feb. 28, 1962 :FILI

INVENTOR. ALTER suYDAM. BY ALFRED asoman.

ATTORNEYS.

Jan. 28, 1964 w. sUYDAM ETAL INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE 6 Sheets-Sheet 3 Filed Feb, 28, 1962 NVENTOR. WALTER SUYDAM. BY ALFRED S. SOBEK.

ATTORNEYS.

Jan. 28, 1964 w. sUYDAMy ETAL 3,119,606

INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE IN V EN TOR.

BY 115. E. M'Mmwf ATTORNEYS.

Jan- 28, 1964 w. sUYDAM ETAL 3,119,606

NTERMEDIATE MILL REHEATING AND PROCESSING FURNACE Filed Feb. '28, 1962 6 Sheets-Sheet 5 'V 1 '66 ,ffl 55 IN VEN TOR. WALTER SUYDAM. ALFRED S. 5OBEK- ATTORNEYS.

Jan. 28, 1964 w. sUYDAM ETAL 3,119,606

INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE Filed Feb. 28, 1962 6 SheetS-Sheeb 6 INVENTOR. WALTER SUYDAM. ALFRED 5.50BEK.

ATTORNEYS.

United States Patent O 3,119,606 INTERMEDIATE MlLL REHEATING AND PROCESSNG FURNACE Walter Suydam and Alfred S. Sobelr, Lebanon Township, Allegheny County, Pa., assignors to Loftus Engineering Corporation, Pittsburgh, Pa., a corporation of Maryland Filed Feb. 2S, 1962, Ser. No. 176,343 10 Claims. (Cl. 263-40) The present invention relates generally to batch heating furnaces and more specifically to the means for loading and unloading material into and out of the furnace.

The invention is illustrated and described in connection with reheating plates during a rolling operation, but is not specifically limited to association with a rolling mill. It will be readily apparent that the furnace and material handling apparatus associated therewith may be employed for many different shapes other than plates.

One object of the invention is to provide a novel form of batch reheating furnace provided with vertically movable side walls for loading and unloading materials into and out of the furnace.

Another object of the invention is to provide a novel form of batch reheating furnace, of the character described, with a longitudinally movable bottom portion.

Another object of the invention is to provide a novel form of loading and unloading device for use with such a furnace.

Another object of the invention is to provide a novel form of batch reheating furnace and material handling device which may be mounted astride a mill runout table.

A further object of the invention is to provide a material handling device for alternately imparting longitudinal and vertical movement to the materials being handled.

These and other objects of the invention will be made apparent from the following specification and the drawings forming a part thereof, wherein:

FIG. l shows a longitudinal vertical section through the furnace and material handling device;

FlG. 2 shows a transverse section through the furnace and in dot and dash lines the movable car and furnace bottom removed from position;

FIG. 3 shows a horizontal longitudinal section through the furnace and associated material handling device;

FlG. 4 shows a schematic arrangement of controls for raising and lowering the furnace side and end walls;

FIG. 5 shows a vertical longitudinal section through the furnace and material handling device with the furnace bottom removed preparatory to transferring a reheated plate to the mill runout table;

FIG. 6 shows a transverse section through the handling device and the vertically movable table;

FiG. 7 shows a plan view of the material handling device and a portion of the associated furnace.

FlG. 8 shows a section through the material handling device and drive for the material handling fingers;

FlG. 9 shows an end elevation of the material handling device; and

FIG. 10 shows a cross section through the material handling fingers and the guide therefor.

Referring now in detail to the drawing, the furnace 1 as disclosed in FIGS. l to 5, comprises a plurality of longitudinally spaced, vertically disposed, members 5 at opposite sides of the furnace in spaced relation thereto. Extending longitudinally of the upper ends of said members 5 at each side of the furnace and connected thereto are a pair of spaced

members

6 and 6. Extending transversely between the members 6 are a plurality of spaced members 7, providing with the

members

5, 6 and 6 a rigid supporting frame for the furnace roof, side 3,119,606 Patented Jan. 28, 1964 ICC and end walls. Depending from the members 7 and secured thereto, in spaced relation to the members S are a plurality of members 8 providing fixed vertical support for the furnace roof as hereinafter discussed.

The furnace structure 1, apart from the supporting frame, comprises integral side and end walls, with separate roof and bottom wall. The integral side walls 9 and end walls 10 are of suitable well known refractory material assembled and connected in a conventional manner. Spaced longitudinally of each furnace side wall 9 and forming a part thereof are a plurality of vertically disposed girder members 11 connected top and bottom by members 12. Enclosing the bottom longitudinal portions of

said walls

9 and 10 are additional members 13 connected with said members 11 and 12. Mounted upon the upper portion of the members 11 of each furnace side wall are brackets 14 to which are rotatably attached rollers 15 riding upon the outer face of the outer flanges of the members 5.

Mounted upon the furnace side wall members 13 are brackets 16 upon which are rotatably attached guide rollers 17 riding upon the inner face of the outer flanges of members 5. Brackets 18 secured to the members 5 limit vertical downward movement of the furnace side and end walls. Vertical support for the furnace integral side and end walls is provided by hydraulic cylinders 19 mounted upon the members 6, 6a at each side of the furnace and provided with rods 20 interconnecting the pistons 19a of cylinders 19 with vertical lifting members 21 secured to the members 11 attached to the furnace side walls 9.

The refractory furnace roof 22 is suspended in fixed relation to the furnace frame members 8 by hanger channels 23 and suitable refractory hanger members 24 embedded in the roof. The periphery of furnace roof 22 is enclosed by the furnace side and

end walls

9 and 10 when the latter are in lowermost position. Adjacent the periphery of the roof 22 is a suitable sand seal 25, into which seal plates 26 attached to the furnace side and end walls engage when the latter are in lowermost position. The roof 22 is provided with a plurality of suitable ports 27 through which heat is introduced into the furnace from suitable banks of burners (not shown) which may be mounted upon the upper face of the roof 22. Suitable outlet tlues 2S for combustion gases may be provided in the furnace side and end walls as indicated. These ports 27 and outlet flues 28, along with the said banks of fuel burners form no part of the present invention and may be of any suitable construction and location.

The refractory bottom 32 for the furnace, as shown in FIGS. 1 and 2 is mounted for longitudinal movement relative to the furnace roof and side walls. Adjacent the base of the members 5 are secured supports 29 upon which are mounted suitable tracks 30 which extend longitudinally of the furnace and outwardly from one end of the furnace. A suitable wheeled car 3l, driven by a suitable motor drive 31a and movable over said tracks supports the refractory furnace bottom 32. This furnace bottom is comprised of a base 32a having extending upwardly therefrom spaced refractory portions 32h for reception of a metal sheet or other shape to be reheated. As shown in FIG'. 2, the furnace bottom portions 32b project above the bottom horizontal plane of the integral side and end walls of the furnace in their lowermost vertical position. The periphery of the furnace bottom has thereon a suitable sand seal 33 into which extends seal plates 34 attached to the bottoms of the furnace side and end walls.

Access to the furnace of IFIG. l for insertion or removal of material within or from the furnace is obtained by raising the furnace side and `end walls by means of the hydraulic cylinders 19. A schematic arrangement of such cylinders and hydraulic controls for raising said integral furnace side and end walls is shown in FIG. 4 of the drawings. Here the -f-our hydraulic cylinders 19, mounted upon the furnace framing members 7 intermediate the furnace end walls, acting through piston rods 20 and furnace members 11 and 21 provide a movable support for the integral furnace side and end walls. A self contained suitable hydraulic unit 35 is mounted upon a suitable service platform 36 disposed in spaced relation to the furnace upon the outer face of the framing members 5. Each cylinder 19, as shown in FIG. 4, has a piston 19a movable therein and hydraulic pressure lines 37 and 38 suitably connected thereto above and below `the piston 19a for alternately adding and Withdrawing fluid pressure for imparting vertical movement to the piston. Preferably the two cylinders 19 at one side of the furnace are connected by common lines 37, 38 and the two cylinders 19 at the opposite sides of the furnace are connected by common :lines 37a and 38a. Lines 37, 37a and 38, 33a are connected with the hydraulic unit 35 through a conventional type directional valve 39 by means of vfeed lines 40 -and 41 respectively. Directional valve 39 has a, piston movably mounted therein and provided with suitable openings through which fluid pressure from unit 35 alternately flows into lines 40 or 41 and therefrom back to unit 35. Normally the piston of directional Kvalve 39 is `in neutral position disconnecting the unit 35 from both lines 40 and 41. The directional valve 39 is electrically controlled through a suitable switch 42 'located at ground level near the furnace and limit switches 43 and 44 selectively engaged by the moving furnace walls in their upper and lower positions respectively. Push button 45 positions directional valve 39 to connect unit 35 with lines 38, 38a to raise the

furnace walls

9, 10, and return fluid in lines 37, 37a to unit 3S. When the rising furnace walls contact limit switch 43, the directional valve is returned to neutral position retaining the

furnace walls

9 and 10 in raised position. When it is desired to lower the said furnace walls, push button 46 of switch 42 is actuated to connect cylinder lines 37, 37a through directional valve 39 with unit 35 to supply hydraulic pressure above pistons 19a and withdraw such fluid from beneath said pistons for lowering the furnace walls. The descending walls upon contacting limit switch 44, causes return of directional valve 39 to neutral position.

Apparatus for handling plate material into and out of the furnace is shown in FIGS. l to 7 of the drawing. Such apparatus is disposed longitudinally of the furnace, at one side thereof and is preferably connected with the furnace buck stays 5. The apparatus has utility apart from the specific furnace design and may be mounted independently of the furnace buck stays.

Referring now to FIGS. l, and 7, the plate handling apparatus comprises a rear truss '47 having top and

bottom chords

48, 49 separated by struts Si) and suitably braced by diagonal members- 51. Such truss is supported in elevated position by

end posts

52, 53 and member 54. End post 53 is connected to beam 55 by a member 56 and a member 57 extends between beam 55 and member 56. Member 54 intermediate its ends is also connected to beam 55 by member 58 which is braced at 59 and 60. Depending from

members

56 and 58 adjacent each end thereof are

vertical members

61 and 62.

Disposed between the

members

61 and 62 is a rigid rectangular frame 63 comprised of two spaced longitudinal trusses 64 and two transverse connecting trusses 65. At each of the four corners of frame 63 are attached top and bottom brackets and wheels 66 which ride on the face of the

vertical members

61 and 62 as the frame 63 moves vertically as hereinafter described.

Spaced longitudinally of frame 63 are transversely extending finger guides I67 secured to the trusses 65 and extending beyond the outer faces thereof. Each guide 67 comprises a pair .0f spaced opposing channels 67a and 67b with the top flanges of each channel secured to the frame trusses 64. Disposed within each guide 67 is a plate lifting finger `68 mounted for reciprocal movement thereon. Each finger 68 comprises an inverted T-shaped rear portion disposed below lguide 67 and having the vertical leg 69 thereof extending upwardly between channels 62a and 62h. Upon each face of leg `69 are mounted a pair of longitudinally spaced rollers 70 engaging the lower flanges of the 'guide channels 67a and 67b for reciprocal movement thereon longitudin-ally of the guide channels. The upper edge of each vertical leg I69, above the rollers 70, is provided with cut teeth 71 for meshing with corresponding teeth of a driving pinion hereinafter described. The forward portions of each of the fingers 68, comprise a downwardly deflected intermediate portion 72 and a substantially horizontal fiat portion 73 for insertion into the furnace. Portion 73 is provided with a depending stiifening rib 74.

fDrive means for the lingers 68 comprises a line shaft 75 journaled in end bearings 76 secured to the outermost guides `67 and provided with intermediate couplings 84. Suitably mounted in fixed relation on shaft 75 are pinions 77 which depend into each guide 67 and mesh with the teeth 71 of the linger leg `69. Shaft 76 intermediate its ends has a sprocket 78 (FIG. 7) mounted in fixed relation thereon. A speed reducer 79 mounted on frame 67 has a sprocket 80 mounted on its slow speed shaft and sprocket 80 is connected by a suitable chain with line shaft sprocket 78 for driving the line shaft. Speed reducer 79 has its high speed shaft suitably connected with a reversing motor `82 provided `with a brake for stopping the motor and fingers 68 in the proper positions.

Frame 63 in addition to supporting fingers 68 for reciprocal horizontal movement, also provides vertical movement for said fingers by moving longitudinally of the vertically disposed frame supporting members 61 yand 62. Referring now to FIGS. 1, 5, 6 and 7, upon suitable platforms 84 and 85 are disposed apparatus for vertically lowering and raising of said frame 63. Adjacent opposite longitudinal sides of frame 63 are steel cables 86 and 86a attached at one end to said frame longitudinal trusses `65. Said cables extending upwardly over wire .rope sheaves 87, rotating on horizontal axles 88, and rearwardly around horizontal sheaves 89 towards the center of the frame `63 where they are connected to the cylinder piston rod 90. Rod 90 is attached to a piston (not shown) within horizontal hydraulic cylinder '91. Consequently as rod 90 moves within cylinder 91 the frame `63 is uniformly raised and lowered. The hydraulic cylinder 91 receives hydraulic Huid power from a self-contained unit 92. The hydraulic unit 92 is suitably connected with cylinder 92 by means of a solenoid actuated valve similar to that as shown on lFIG. 4. Such valve to be controlled by the operator on the main floor by a suitable pushbutton for feeding to or removing hydraulic pressure from cylinder 92 to raise or lower frame 63.

The furnace and plate handling `apparatus are constructed and intended to be used together in connection with a rolling mill wherein large metal plates or other shapes may be reheated during the rolling operation. Each may be used separately, with desired structural modifications for other reheating or handling requirements.

Referring now to the operation of the furnace as disclosed in FIGS. l and 2, the furnace 1 is shown as being disposed above and straddles a mill runout table 2. Assuming that the plate 3, as shown in FIG. l has been reheated in the furnace to proper temperature for return to the rolling mill for further rolling and a plate within the rolling mill requires further reheating and has been removed from the mill upon the mill table and beyond the furnace. An operator presses the push button 45 of FIG. 4 causing fluid pressure from unit 35 to be applied to hydraulic lift cylinders 19. Push button 45, acting to close the electrical circuit between lines 38, 38a and valve 39, connects the unit 36 with hydraulic pressure lines 33 of all cylinders 19 raising

furnace walls

9 and 10 until they contact limit switches 43, which opens the electrical circuit permitting valve 39 to return to neutral position and cutting off hydraulic pressure to cylinders 19. In this position the bottoms of the furnace walls are above the horizontal pl-ane of plate 3 within the furnace.

The operator then actuates another suitable pushbutton for closing an electrical circuit actuating hydraulic cylinder 91 to lower the ringer supporting frame 63 until the finger portions 73 thereof are below the horizontal plane of the bottom of plate 3 within the furnace. Lowering movement of the frame 63 is then discontinued. Motor 32 on frame 63 is then actuated and acting through rotation of speed reducer 79 drives line shaft 75 and pinions 77 thereon engaging with the teeth upon finger sections 69 to move the fingers into the furnace between the furnace bottom portions 32h on car 31 and beneath plate 3. Frame 63 may then be raised slightly to lift plate 3 and car 31 actuated through its motor 31a to run the car from beneath the furnace walls along track 39. Cylinder 91 may then be reactivated to lower frame 63 and fingers 68 thereon to deposit reheated plate 3 upon the mill table 2 below the furnace. Plate 3 may then be moved by the rollers of mill table 2 into the mill.

The plate to be reheated and now upon the mill table 2, it can then be moved over the table rolls and above the finger portions 73. Frame 63 may then be raised to bring the plate from the mill table to within the furnace and above the plane of the top of the furnace floor of car 31 when in position. Thereafter car 31 is actuated through its motor 31a to return the car into position beneath the furnace walls and frame 63 lowered to place the plate to be reheated upon the furnace floor portions 32b. Fingers 68 may then be retracted by motor S2 of frame 63 into the position shown in FIG. 1. Thereafter cylin ders 19 are actuated through pushbutton 46 which moves valve 39 to connect hydraulic unit 35 with lines 3S to withdraw fluid pressure from cylinders 19 to lower the furnace integral side and end walls into the position shown on FIG. 1 where the walls engage limit switches 44 returning valve 39 to neutral position and holding the walls in the fixed position suspended by rods Z-t connected with the piston 19a of cylinders 19. The plate within lthe furnace may now be reheated to the desired temperature.

As will be apparent from FIG. l of the drawing, plate 3 cannot be removed from the furnace by ngers 68 and placed upon the mill table 2 while the car 31 is positioned beneath the furnace walls. However, the furnace walls may be raised, as hereinbefore described, and the car 31 run out of position, whereupon the plate which has been reheated may be lifted from the car and placed upon the mill table by any suitable means such asv an overhead crane or perhaps a lift truck. The same means can reload from the mill table and onto the car, a plate which is to be reheated. The car can then be positioned beneath the furnace walls and the walls lowered as previously discussed.

The plate handling equipment herein described, although limited to loading to and from the mill table, has advantages when used with the furnace. Likewise the plate handling equipment has many possible uses apart from its association with the specific form of furnace.

lVe claim:

1. In an intermediate mill reheating and processing furnace, in combination, a wheeled member having upon the upper face thereof a refractory surface forming a furnace bottom Wall, a vertically disposed self-sustaining structure straddling said wheeled member in spaced relation thereto and having a rigid portion overlying said furnace bottom wall in vertically spaced relation thereto, a suitable refractory member suspended from said structure rigid portion in vertical spaced relation to said furnace bottom wall providing a furnace roof, a suitable integral refractory member defining the furnace side and end walls and enclosing said furnace roof, rigidifying means disposed upon said furnace side walls and having portions thereof slidably engaging said structure for guided vertical movement of said side walls relative to said furnace roof and above said furnace bottom wall, and means on said structure rigid portion connected with said side wall rigidifying means for raising and lowering said integral furnace side and end walls relative to said furnace bottom wall.

2. The furnace as defined in claim 1, wherein the said wheeled member straddles a rolling mill run-out table for movement longitudinally thereof, the said furnace roof and bottom walls have surrounding their upper peripheral surfaces a suitable heat sealing means and the integral furnace side and end walls have upon their upper and lower peripheral surfaces sealing members releasably engaging with the said heat sealing means when the furnace side and end walls are in their lowermost vertical position.

3. The furnace as defined in claim 2, wherein a second rigid supporting structure is disposed adjacent a side wall of said furnace and material handling means mounted upon said second supporting structure for vertical reciprocal movement thereon between said furnace bottom wall and mill run-out table and for horizontal reciprocal movement relative to said furnace bottom wall when the furnace side walls are in elevated position.

4. Apparatus for reheating metal plates being processed by a suitable rolling mill equipped with the usual nun-out table `at one side thereof, in combination a rigid supporting frame strad-dlling said run-out table and extending above same,

a suitable refractory furnace roof member suspended from Said frame in vertical spaced relation to said table,

-a suitable refractory' fur-nace bottom member disposed below said furnace roof member and in vertical spaced relation to said table,

means supporting said :furnace bottom member for movement longitudinally of said table,

-a suitable integral refractory member defining side and end walls for said furnace and encllosing said furnace roof in spaced relation thereto and in overlapping relation to the horizontal plane of said furnace bottom wall,

means mounted upon ,the exterior of each furnace side wall and engaging said supporting frame for movement relative thereto, and

means on said frame for suspending said flurnace side and end wails from said supporting frame and for imparting selective Ivertical reciprocal movement thereto relative to `said furnace roof and bottom members.

5. Apparatus as defined in claim 4, wherein a second vertically extending frame is disposed ladjacent said millrun-out table in horizontal spaced relation thereto and to a side wall of the furnace, a rigid platform disposed within said frame and slidably engageabde therewith for vertical reciprocal movement thereon, plate engaging and supporting means mounted upon said platform for horizontal movement relative thereto and across the horizontal plane of said furnace bottom wall when the furnace side and end walls )are in elevated position and means suspending said platform upon said fname for vertical reciprocal movement between the horizontal planes of the Ifurnace bottom wall and said milll run-out table.

6. In an intermediate mill reheating and processing furnace, in combination,

movable means straddling la mill run-out table,

a refractory furnace bottom wall on said means and above said Irun-out table,

a furnace roof portion suspended in vertical spaced relation to said furnace bottom Wall,

integral furnace side and end walls enclosing said yfurnace roof portion and disposed in overlapping relation to said furnace bottom wall,

means suspending said furnace side and end walls for selectively raising and lowering same relative to said furnace bottom wall,

sealing means mounted upon said furnace roof portion and bottom Wall adjacent the peripheries thereof, and sealing means mounted upon the upper and lower peripheries of said side and end Walls for engaging with the sealing means of the said furnace top and bottom walls.

7. The furnace as defined in claim 1, wherein a rigid vertical frame is disposed adjacent said furnace,

a platform means is mounted Within said frame for vertical reciprocal movement thereon, and

material handling members are mounted upon said platform means for selective horizontal reciprocal movel ment thereon and across the horizontal plane of said furnace bottom wail.

8. In a material heating furnace, in combination,

spaced vertically disposed members,

a refractory furnace matenial receiving bottom wall `disposed between said vertical members for horizontal movement relative thereto,

a refractory furnace roof suspended from said vertical members in vertical spaced relation to said furnace bottom wall,

integral refractory furnace side and end walls enclosing said furnace roof for movement relative thereto and overlying said furnace bottom wall,

means suspending said integral furnace side and end walls from said vertical members for selective vertical movement relative to said furnace roof and bottom members, and

heat sealing means mounted on said integral side and end wallls for overlying and engaging with heat sealing means on said roof and bottom wall.

9. The material heating furnace as defined in claim 8 wherein said refractory furnace side and end walls are provided with vertically disposed rigidifying bracing members, and

8 guide means secured to at least some of said bracing members on each furnace side wall and engaging said spaced vertical members as the furnace side and end walls move relative to said furnace bottom wall between said vertical members. 10. A material handling device for imparting reciprocal selective vertical and horizontal movements to material engaged thereby comprising,

an upright rigid rectangular frame having four upright members arranged in rectangular form,

a rigid rectangular platform disposed within said frame and provided with interconnected truss members at each side of the platform,

roller means on said truss members engaging said frame upright members -for movement therealong,

a plurality of finger guides comprised of spaced pairs of opposing channels spaced longitudinally of said platform and extending transversely beneath same,

material handling fingers disposed between and supported upon said finger guides,

each said fingers comprising a rear inverted T shape portion disposed between said channels and a forwardly extending material engaging portion disposed below the horizontal plane of said finger guide channels,

the upper face of the stem of said inver-ted finger portions, between said guide channels, having pinion engaging teeth thereon,

driving means mounted upon said platform comprising a drive shaft extending transversely of said finger guides having toothed pinions fixed to the shaft over each finger in engagement with the teeth of said fingers, a drive gear on said shaft and a reversible electric motor connected with said drive gear, and

means mounted on said frame for selectively raising `and lowering said platform upon said frame upright members.

References Cited in the file of this patent UNITED STATES PATENTS 1,217,251 Wikstrom Feb. 27, 1917 1,840,327 Paulsen Jan. 12, 1932 2,029,286 Bent et al Feb. 4, 1936 y aria.,

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No 3 119606 January 28V 1964 Walter Suydam et ale It s hereby Certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as Corrected below.

In the grant line l and in the heading to the printed specification, `line 4 before "Lebanon" each occurrence,

insert u Mount Signed and sealed this 16th day of June 1964o SEAL A(ttest:

ERNEST WQ SWIDER EDWARD J. BRENNER Atesting Officer Commissioner of Patents

Claims

1. IN AN INTERMEDIATE MILL REHEATING AND PROCESSING FURNACE, IN COMBINATION, A WHEELED MEMBER HAVING UPON THE UPPER FACE THEREOF A REFRACTORY SURFACE FORMING A FURNACE BOTTOM WALL, A VERTICALLY DISPOSED SELF-SUSTAINING STRUCTURE STRADDLING SAID WHEELED MEMBER IN SPACED RELATION THERETO AND HAVING A RIGID PORTION OVERLYING SAID FURNACE BOTTOM WALL IN VERTICALLY SPACED RELATION THERETO, A SUITABLE REFRACTORY MEMBER SUSPENDED FROM SAID STRUCTURE RIGID PORTION IN VERTICAL SPACED RELATION TO SAID FURNACE BOTTOM WALL PROVIDING A FURNACE ROOF, A SUITABLE INTEGRAL REFRACTORY MEMBER DEFINING THE FURNACE SIDE AND END WALLS AND ENCLOSING SAID FURNACE ROF, RIGIDIFYING MEANS DISPOSED UPON SAID FURNACE SIDE WALLS AND HAVING PORTIONS THEREOF SLIDABLY ENGAGING SAID STRUCTURE FOR GUIDED VERTICAL MOVEMENT OF SAID SIDE WALLS RELATIVE TO SAID FURNACE ROOF AND ABOVE SAID FURNACE BOTTOM WALL, AND MEANS ON SAID STRUCTURE RIGID PORTION CONNECTED WITH SAID SIDE WALL RIGIDIFYING MEANS FOR RAISING AND LOWERING SAID INTEGRAL FURNACE SIDE AND END WALLS RELATIVE TO SAID FURNACE BOTTOM WALL.