US1992467A - Heat-treating furnace - Google Patents

Description

Feb.' 26, 1935. W; E, BLYTHE; 1,992,467

` HEAT TREATING FURNAGE Original Filed May l2, 1933 5 Sheets-Sheet 3 Patented Feb. 26, 1935 UNITED STATES HEAT-TREATING FURNACE William E. Blythe, Birmingham, Mich., assigner to Driver-Harris Company, Harrison, N. J., a corporation of New Jersey Application May 12, 1933, seria1No.s7o,649 Renewed July 11, 1934 9 Claims.

My invention relatesto high temperature heat treating furnaces of the type in which material to be treated is conveyed through the furnace on rolls and comprises an improved furnace of this character.

An object of the invention is to improve the construction and operation of the now existing furnaces of this type by substituting therein conveyor rolls of improved construction for the water cooled steel conveyor rolls now in common use whileutilizing without substantial modification much of the present expensive equipment of the furnace.

Another object of the invention is to provide in newly constructed or in existing furnaces improved conveyor rolls of relatively small diameter adapted to withstand the intense heat of the furnace, and to provide supporting means therefor which will insure that the rolls run true.

The several features of the invention whereby the above-mentioned and other objects of the invention may be obtained, will be readily understood from the following description and accompanying drawings, in which:

Fig. 1 is a transverse sectional view, partly in elevation, of a portion of a furnace embodying the features of my invention in their preferred form;

Fig. 2 is a. detail sectional view on an enlarged scale taken along the line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view, partly in elevation, of a portion of a furnace illustrating a modification of the invention;

Fig. 4 is a detail sectional view, on an enlarged scale, taken along the line 4-4 of Fig. 3; and

Fig. 5 is atransverse sectional view, partly in elevation of a portion of a furnace illustrating still another embodiment of the invention.

The furnace illustrated in the drawings is of the type of the one described and claimed in my Patent No. 1,843,440, dated February 2, 1932, and pending application Serial No. 653,656, filed Jan. 26, 1933. This furnace is provided with a,

furnace chamber having side walls 2, a top wall 4 and a bottom wall 6 and conveyor rolls-extending transversely of the furnace chamber. Each conveyor roll may comprise a hollow shaft 8 and, if desired, material conveying disks 10 secured thereon. The disks 10 of the several rolls are preferably arranged in staggered relation so as to permit each disk to extend into the space between adjacent disks of adjacent rolls.

In theembodiments of the invention illustrated in Figs. 1 to 4 inclusive each conveyor roll 8 is supported by a pair of bearing rollers 12 positioned within the furnace chamber at a point substantially midway of the length of the conveyor roll. The pair of bearing rollers 12 are mounted in a recess on a support or cradle 14 secured to a stool or pedestal 16 by bolts 18. Preferably each bearing roller 12 is provided with an annular cored out recess 20 to receive projections on the support 14 to prevent the bearing roller from working out of the bearing recess in the support. The support 14 is made in two sections that are arranged in opposed relation to permit the bear-v ing rollers to be easily assembled therein. A hood 22 that may also be made in two sections extends over each conveyor roll and has its ends secured, as by pinning or welding, to the sections of support 14. This hood prevents dirt and scale from getting on the bearing rollers, and also ensures against the conveyor roll working off of the bearing rollers.

Each pedestal 16 extends downwardly through the bottom of the furnace chamber and has its lower end supported on a steel I-beam 24 which extends transversely of the furnace.

The conveyor rolls 8, bearing rollers 12, supports 14 and pedestals 16 all may be made of nickel-chromium-iron or other suitable heat resisting alloy.

In the embodiment of the invention illustrated in Fig. 1 each conveyor roll 8 extends substantially the width of the furnace chamber, and is coupled by means of suitable flexible couplings 26 of heat resistant alloy between sections 28 and 30 of a hollow steel driving shaft; the ends of the sections 28 and 30 to which the roll 8 is coupled extending through aligned openings 32 in the side walls 2 of the furnace and through suitable stuffing boxes 34 mounted on the outer walls of the furnace. Each section of the steel drive shaft is hollow and is water cooled as by a valve controlled pipe 36 connected at one end with a water main 38 and extending ,axially through the shaft section to a point adjacent the coupling 26. The shaft sections 28 and 30 are supported in fixed bearings 40 positioned outside of the furnace chamber. A main drive shaft 42 drives the steel drive shaft sections and conveyor rolls through-bevel gears 44'.

By embedding the lower portions of the pedestals 16 in the masonry of the bottom or base 6 of the furnace, and mounting them on steel supports well protected from the heat of the furnace as above described, they are rigidly held and effectively stand up under the weight of the conveyor rolls and work.

In order to compensate for growth in the diameters of the conveyor rolls, to insure proper engagement of the bearing rollers with the conveyor rolls and to maintain the rolls level, the bearing rollers are adapted to be adjusted vertically and this may be done during operation of the furnace. To provide for this, the bottom of each pedestal rests upon a wedge member 46 that is adapted to be moved in opposite directions to raise and lowerthe pedestal, by means of a shaft 48 that has one end connected by a swivel joint with said wedge member. Said shaft has screw-thread engagement with a fixed member 50 and extendsoutside of the furnace to be turned by a hand-crank 52.

From the above description of the construction illustrated in Figs. 1 and 2 it will be apparent that the provision of the central bearing support for each conveyor roll within the furnace chamber together with .the flexible couplings to the steel drive shaft sections gives adequate support for the conveyor roll and permits the use of rolls of relatively small diameter because but a relatively short span between points of support is exposed to the intense heat of the furnace. The provision for adjustment of the bearing support for the conveyor roll insures proper support for the roll even after growth. Moreover, these advantages may be obtained without extended modication of equipment in existing furnaces. 'I'his is true because with the construction illustrated, the main drive shaft 42, bearings 40, and water supply system are all parts of standard equipment used with furnaces having water cooled conveyor rolls and the drive shaft sections 30 and 32 may be parts of extensions of such a conveyor roll from which the central section has been removed. 'I'hus the only new parts necessary to obtain the improved operation possible with the present construction are the couplings 26, conveyor rolls 8, bearing rollers 12 and the supporting means therefor.

Certain of the advantages of the sectional construction of the conveyor rolls or roll shafts illustrated in Figs. 1 and 2 may be obtained and elimination of Water cooling may be effected in some instances, if the steel drive shaft sections and coupling thereto are replaced, as indicated in Fig. 3, by shaft extensions 54 integral with the conveyor rolls 8, the extensions 54 passing through the openings 32 in the end walls of the furnace and through the stuffing boxes 34 and being supported at their ends by fixed bearings 56 outside the furnace chamber.

Drive shaft 42 may be geared directly to one extension 54 by pinion gears 58 to drive the conveyor roll or, if desired, an intermediate section of steel shafting may be coupled to the extension 54 and driven by the gears 58. Conveyor rolls 8 are supported adjacent their center by bearing rollers 12 carried by support 14 and adjustable pedestal 16 as in the construction of Fig. l. With the arrangement illustrated in Figs. 3 and 4, flexible couplings of heat iesistant alloys are not required nor is water cooling of any part necessary.

In each embodiment of the invention so far described a central bearing support for each conveyor roll is illustrated. In relatively narrow furnace chambers this central bearing support may be omitted and the relatively shorter conveyor rolls supported at their ends only. Such an arrangement is illustrated in Fig. 5 wherein the only support for the conveyor rolls 8 coinprises the exible couplings 26 which, as in Fig.

1, couple the conveyor rolls between water cooled sections 28 and 30 of a steel driving shaft.

The following is claimed:

1. In a heat treating furnace of the class described, the combination of a furnace chamber having side walls withaligned openings therein, conveyor rolls within the chambery in alignment with the openings in the side walls, shafts extending through said openings, exible couplings connecting the ends of said rolls to said shafts, and bearings for said shafts positioned outside the furnace chamber.

2. A structure according to claim 1 in which said shafts are cooled by the circulation of a cooling fluid therethrough.

3. In a heat treating furnace of the class described, the combination of a furnace chamber having side walls, conveyor rolls extending across the furnace chamber, each roll having shaft extensions projecting through openings in the side walls, bearings for said shaft extensions arranged outside of the furnace chamber, a bearing for an intermediate portion of the roll arranged within the furnace, and means for adjusting said last mentioned bearing vertically during the operation of the furnace.

4. In a heat treating furnace of the class described, the combination of a furnace chamber having side Walls with pairs of aligned openings therein, conveyor rolls within the chamber in alignment with the openings in the side walls, shafts connected with said rolls and extending through said openings, bearings for said shafts positioned outside the furnace chamber, a bearing support for each roll positioned within the furnace substantially midway between the side walls, and means for driving said conveyor rolls and shafts.

5. The combination according to claim 4 wherein said shafts and rolls are iiexibly coupled together within the furnace chamber adjacent the side walls, and wherein means are provided for water cooling said shafts. said rolls being of heat resistant alloy and said shafts being of steel.

6. The combination according to claim 4 wherein said shafts are integral with said rolls and form extensions thereof of relatively smaller diameter, said rolls and shafts being of heat resistant alloy.

7. In a heat treating furnace of the class described, the combination of a furnace chamber having side ^walls, conveyor rolls extending between the side walls, a bearing support for each roll positioned within the furnace and spaced a distance from the side Walls, means accessible without the furnace chamber for adjusting said supports to compensate for growth of the rolls, means outside of the furnace chamber for supporting the ends of each of said rolls, and means outside of said chamber for driving said rolls.

8. The combination according to claim '7 wherein the side walls of said furnace have openings therein in alignment with said rolls and wherein the means for supporting the ends of said rolls include shafts flexibly coupled to said rolls Within the furnace adjacent the side walls thereof and extending through said openings, said shafts being supported externally of the furnace and being driven by said driving-means.

9. The combination according to claim '7 wherein the side walls of said furnace chamber have openings therein in alignment with said rolls, said rolls having extensions passing through said openings and wherein said means for supporting the ends of said rolls comprise -lxed bearings for said extensions positioned outside of the furnace chamber. i

WILLIAM E. BLYTHE.

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