US2534021A - Heating apparatus for heating ends of elongated workpieces in a continuous process - Google Patents

Description

Dec. 12, 1950 F o HESS ET AL 2,534,021

HEATING APPARATUS POR HEATING ENDS OF ELONGATED WORK PIECES IN A CONTINUOUS PROCESS Filed Feb. 13, 1947 4 Sheets-$heet 1 &

jag/MM HTTOF/VEV Dec. 12, 1950 F o HESS ETAL 2,534,021

HEATING APPARA'II'JS FOR HEATING ENDS OF ELONGATED WORK PIECES IN A CONTINUOUS PROCESS Filed Feb. 13, 1947 .4 Sheets-Sheet 2 1 i598 Fee-0597c 0. A issa Fae-0 Maya By fbW/n/ 19 I772 Dec. 12, 1950 F. o. HESS ETAL 2,534,021

HEATING APPARATUS FOR HEATING ENDS OF ELQNGATED WORK PIECES IN A commuouswaocsss Filed Feb. 15, 1947 4 Sheds-Sheet 3 Dec. 12, 1950 Fl 0. HESS ETAL 2,534,021

HEATING APPARATUS FOR HEATING ENDS OF'ELONGATED WORK PIECES IN A cou'rmuous PROCESS Filed Feb. 13, 1947 4 Sheets-Sheet 4 arrdrwir Patented Dec. 12, 1950 UNITED STATES PA'IENT OFFICE- 2,534,021 HEATING APBARATUS FOR. HEATING ENDS or ELoNGATEDWQR-KBIE E I A C N- TINUOUS I'IiQQE Frederic 0. Hess, Philadeiphia, and Fred Maud and Edwin F. Stoert'z, North Hills, Pa, assignors to Selas Corporation of America, Philadelphia, Pa, a corporation of Pennsylvania- Application February 13, 1947, Seriai No. 728,300

7 Claims.

The present invention relates to heat treating apparatus, and the primary object of the present invention is to provide improved apparatus for heating end portions of metallic rods andother elongated metallic articles. More specifically, the objectof the invention is to provide s m nd e fe tive ap ra us or pi y a unifc mly ea i on end of a h of was o ana o us elon a ed work ie w h a ef ccessively moved along a heating path in the course of which eachwork piece endto be heated is moved through the length of an elongated heating furnace chamber by an endless chain or belt conveyor alongside the furnace chamber. The chamber is formed with a slot in one side wall which forms a path for the movement of a portion of each work piece intermediate the end portion within the furnace chamber and the external portion of the work piece which is connected to the conveyor.

In its preferred form, the invention is characterized by the vertical disposition of the furnace chamber and by the arrangement of the chain conveyor so that the work pieces treated may be attached to successive upwardly moving portions of the conveyor so that each work piece end is moved into the furnace chamber at its upper end and is then moved downwardly through the furnace chamber. In its preferred form, the conveyor is arranged to permit each workpiece to be discharged at the bottom of the furnace chamber by gravitational force as the portion of the conveyor chain previously supporting the work piece moves through a portion of its path of movement below the furnace and leading away from the vertical.

The invention is well adapted for use in heating ferrous bodies to forging temperatures and for other uses. For example, the invention is well adapted for use in heating brass tubes to annealing temperature.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a partof this specification. For a better understanding of the invention, however, its advantages and specif c objects attained with its use, reference should be had to the accompanying drawing and descriptive matter in'which we have illustrated and described a preferred embodimen f he inv nt on- Fig. l is an elevation of a continuous furnace and its conveyor mechanism;

Fig. 2 is .an elevation taken at right angles toFig. 1

Fig. 3 is an elevation taken similarly to Fig. 2, but showing the furnace structure only;

Fig. 4. is a section on the line i.4 of Big. 3';

Fig. 5 is a plan View of the furnace structure shown in Figs. 3 and l; and

Fig. 6 is a section on the line B6 of Rig. 4.

The apparatus shown in the drawings Chm? prises a base structure A which supports a Vere tioally elongated furnace structure B, and. an associated conveyor mechanism comprising a supporting framework C alongside the furnace structure is and extending between upper and lower levels; respectively above and below :the top and bottom of the furnace structure. Mounted in the framework C is a conveyor mechanism comprising two side by side link belts or chain conveyors D, each running over a separate set of sprocket wheels E, E E and E Each of the sprocket wheels is mountedon and secured to a corresponding shaft'journalled in the supporting framework and on which the corresponding sprocket wheel of the other set is mounted and secured. As shown, theendless sprocket chains are kept moving continuously in the direction indicated by the arrows in Figs. 1 and 2, by a driving motor F suitably connected through a variable speed driving mechanism G to one of the-sprocket wheel shafts. As shown that shaft is the one which-carries the sprocket wheels E as well as a sprocket wheel E fl he latter is connected by a sprocket chainbeltuG to the output sprocket wheel G of the driving mechanism G. The latter is drivenby the motor F through a belt l running over a pulley E carried by the motor shaft and overthe input pulley wheel G of the driving mechanism.

As shown, the framework 6 may include adjusting means FA for vertically adjusting the shaft carrying the sprocket wheels E so as to avoid undesirableslackness inthe conveyor chains D. A pivoted belt tighteninglever E carrying an idler li at one end which isin engagement with the sprocket chain G, keeps the latter-sufhciently taut; The belt E may be kept under suitable tension by an adjusting mechanism E of .coiiventional form for bodily adjusting the motor F toward and away from the variable speed drive unit dach sprocket chain D is provided-with work hoiders l3 distributed at suitable intervals along the length of the sprocket chain. Each pair of work holders D"carried by the two sprocket chains D in end to end relation with one another, constitutes work support for a horizontally disposed bar or other elongated work piece d; The latter may be put in placeinthetwo work supports while they are moving upwardly at the left side of the supporting framework C, as seen in Fig. 2, through a convenient loading level which may be that of the top of the base structure A. Each work piece thus mounted in a pair of work holders, is carried by the latter upward to, and thence over sprocket wheels E, and thence to and over sprocket wheels E and thence down to and through the level of the axis of the sprocket wheels E As each pair of Work supports D passes below the level of said axis and thence toward the under side of the sprocket wheels E its path of movement is inclined to the vertical and the work'supports are inverted sulficient to permit the work piece previously held in the work supports to move out of the latter under the action of gravity. Each work piece d thus discharged, falls into a downwardly inclined chute or guideway H through which the work pieces successively heated in the furnace B pass away from the heat treating apparatus shown in the drawings,

The work holders D may take various forms. In the simple form shown, each work holder D' comprises a link of the corresponding sprocket chain D, provided adjacent each end with a rib D extending outwardly away from the chain. The outer end portion of each rib D is bent toward the other rib so that the body of the link and the two ribs form a C-shaped saddle or under cut seat in which a work piece is securely held by gravity until the work supports are partly inverted. In the particular construction shown, each link of each conveyor chain D is formed with a pair of ribs D and constitutes a work holder D. To insure the discharge of each of the successively advanced work pieces at exactly the same discharge level, stationary retaining devices D one adjacent each chain D, are disposed to hold each work piece in the corresponding pair of work holders until their rear ribs begin to move horizontally away from the retaining device D The devices D are attached to the framework C and cause both ends of each work piece to leave the corresponding work holders at about the same time.

The furnace structure B is formed with a vertically extending furnace chamber B which is The wall of the chamber 3;

through which each work piece at moving downward from the sprocket wheels E to the sprocket wheels E extends into the furnace chamber.

The form and dimensions of the furnace chamber B and its heating means may vary with the conditions of use. The particular furnace structure shown by way of example in Figs. 1 and 2 was devised with particular reference to use in heating the ends of work pieces d in the form of round bars of ferrous material about six feet long and about seven-eighths of an inch in diameter, to a temperature of approximately 2250 F., preparatory to the subjection of the heated end of the bar to a forging operation, such as that required to adapt the bar for use as an automobile sway-bar. The main lower portion of the particular furnace chamber B, shown by way of example, is rectangular in cross-section with a horizontal length of about 10 or 11 inches and a breadth of 5 or 6 inches, and the masonry wall of the chamber in which the slot B is formed 4 space above the main lower heating space and of somewhat smaller cross-section. A plurality of distributed furnace wall burners I are incorporated in each of the opposing side walls of the main lower portion of theheating chamber B.

In the particular furnace form shown, the burners in each side wall of the chamber B are arranged in two side by side rows with seven burners in each row, and each of those burners is advantageously of the well known and widely used type disclosed in Hess Patent No. 2,215,079, of September 1'7, 1940. Such a burner is characterized by the supply of a combustible mixture of air and gas to a shallow cup-shaped combustion chamber I in fine streams distributed about the combustion chamber axis and so directed that combustion is effected at the surface of the combustion chamber and heats the ceramic wall of the combustion chamber to a high temperature so that it emits a relatively large amount of radiant heat. Combustible mixture is supplied to each burner through an individual supply passage I extending from the combustion chamber 1 of the burner to the adjacent side wall of the furnace structure and receiving a combustible mixture of air and gas through external piping which may be arranged and associated with valves for regulating the supplies to the different burners in the manner now customarily employed in gas fired furnaces having a multiplicity of distributed furnace wall burners.

To minimize the heating effect of the furnace on the supporting structure A, water walls J are provided at the bottom of the furnace, and water walls J are provided at the side of the furnace facin the conveyor mechanism.

To minimize the chimney stack action of the furnace, the opening at the upper end of the furnace chamber B, through which the ends of the work pieces d are moved downward into the furnace chamber, is made as small as is practically possible by the use of metal plates K and K. The plates Kand K are arranged at the opposite sides of the slot-like space'through which the ends of the Work pieces pass downward to the furnace chamber B and slot B Each of the plates K and K may be adjusted toward and away from the other by means of a corresponding bolt and nut connection K between the cover plate and a bracket K anchored to the furnace structure. limits the length of the open space between the adjacent edges of the cover plates K and K,. and is adjustable to vary the length of said space by means of a threaded connection K between the plate K and a bracket K suitablyanchored to the furnace structure. V

As shown, the actual width of the outer. edge of the vertical slot through which the work pieces at extend into the furnace chamber... is fixed by the adjustment of cover plates Land'L. which maybe formed of stainless steel and rest against the chamber cooling walls J at the side The. cover plate K 8 of the furnace structure facing the conveyor mechanism. The distance between the adjacent edges of the cover plates L and L need be but a trifle greater than the diameter of the work piece portions passing between those edges, as is shown in Fig. 6.

In. the contemplated use of the apparatus shown" in the drawings, a workpiece-d is seated in each work support formed by an end to end pair'of work holder elements D of theconveyor chains D, as said work holders pass through the work charging or loading level. Thatlevel may bethe level of the top of'the base -A many other convenient level. The work pieces may be mandaily placedin the work holders. Except for the insertion of the. work pieces in the work holders, the operation of the apparatus shown is purely automatic and continuous. With burners of the type described and arranged at the opposite sides of the heating chamber B", as shown, the heating operation is rapid and" uniform. A red; end' of the dimensions stat'edabove, by way of example, maybe heated from atmospheric temperature to a temperature of 2250 or so, during a periodof about 'four'and' one-half minutes in which the end moves from the: topof the furnace. chamber B to its lower end; I his means that if the combustion chamber length is 6"feet, the linear travel of the belt maybe" about one andone-third feet. per minute, and if'each belt link serves-as a work holder and is two inches long, heated: rods will be discharged from the apparatus at the rate of eight pieces per minute, or 480 pieces perhour.

With the vertical disposition of the furnace chamber and the movement of the work pieces downward through the furnace chamber, as the hotproducts of combustion move upward from the level of the uppermost burner I to the: top of the furnace, they give up much of theirxheat. to

the work pieces which are cold when they enter the furnace chamber. This preliminary heating of the work pieces inthe entrance portion of the furnace chamber not only increases the thermal efficiency of the furnace, but helps to avoid overheating the space surrounding the heat treating apparatus.

As will be apparent to those skilled in the art, the temperature of 2250 mentioned above is a typical forging'temperature for ferrous metals, and apparatus of the character shown in the drawings is of a special utility in heating small work pieces of the character mentioned above to forging: temperatures, because of the: uniformity of the heating operation and the rapidity with which it .iseffected. Thatrapidity contributes directly to a reduction of the amount of scale formed in the furnace; Furthermore the scale formedas the work pieces move downwardly through the furnace chamber and not adhering-to the work pieces, isfree' to'fall downward through the furnacechamber and out through the open lower endof the latter. Moreover, much of the scale adhering to the workpieces as they reach the discharge level, is dislodged and separated from the work pieces as the latter fall out of the work holders on to the discharge guides and roll down the latter. In forging operations, the uniform heating of the work to the proper forging temperature, and the reduction of the scale on the work pieces to a minimum, are two elements of the operation contributing materially to the efliciency and low cost or the forging operation. A major cost item in the forging of small ferrous bodies is the cost of forging die andthe cost of die re pairs and replacements. Another substantial cost item is the loss of forged products, which, because of improper heating, are inferior and must-be treated as scrap.

While the invention has special advantages foruse in heating ferrous work piecesto a forging temperature, it may also beused for manyother purposes. In particular, it may be used in annealing ferrous and. non-ferrous metallic bodies at temperatures substantially lower than forging temperatures and may be of the order of 1400" F. to 800 F, respectively.

While in accordance with the provisions of the statutes, we have illustrated and described the best form of embodiment of the invention now known to us, it will be apparent to those skill'edin the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention as set forth in the appended claims, and that in some cases certain features of the invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. Heat treating apparatus comprising: structure providing a vertically extending refractory lined chamber having end openings at the top and bottom and a slotted side wall, conveyor means adjacent to said chamber for carrying and vertically transporting horizontally disposed elongated work pieces to be: heated at an end thereof} said conveyor means being positioned with respect to said structure so that the ends of the Work pieces to be heated project into the chamber through the slotted wall thereof during verticaltransport and enter and leave the cham her through the end openings and scale formed on the ends of the work pieces during heating thereof will freely fall downwardly through the chamber and pass therefrom through the bottom and opening, means to drive said conveyor means in a direction to move saidwork pieces downwardly through said chamber, and means for directly heating said chamber comprising opposed burners incorporated and distributed in the refractory lining thereof, on sides adjacent to the side of said chamber having said slot therein, the portion of the work pieces projecting into said chamber being in between the opposed burners, to heat the ends of the work pieces during. transport through the chamber toa-n elevated. temperature suitable for forging and like forming operations.

2; Heat treating apparatus comprising struc-. ture providing a vertically extending refractory lined chamber which is open at the top and bottom and slotted at a side wall thereof,.o1pposed burners located in the side walls of said chamber at right angles to the side having said slot, conveyor meansadjacent to said chamber for carrying. andvertically transporting in spaced apart relation horizontally disposedelongated work pieces to be heated at an end thereof,.sald conveyor means being positioned with respect to said structure so that the ends of the work pieces to be heated project into the chamber through the slotted wall thereof and in between the burners during vertical transport and enter and leave the chamber through the openings at the top and bottom, respectively, means to drive said conveyor means in a direction to move said work pieces downwardly through said chamber, means for firing said chamber to an elevated temperature, said conveyor means including 0- for discharging heated work pieces therefrom by;

gravity.

3. Heat treating apparatus as set forth in claim 2 including chute means to receive the elongated work pieces from the conveyor means.

4. Heat treating apparatus comprising structure providing a vertically extending refractory lined chamber having end openings at the top and bottom and a slotted side wall, conveyor mechanism adjacent to said chamber for carrying and vertically transporting in spaced apart relation horizontally disposed elongated Work pieces to be heated at an end thereof, said conveyor mechanism being positioned with respect to said structure so that the ends of the work pieces to be heated project into the chamber through the slotted wall thereof during vertical transport andenter. and leave the chamber through the end openings, means for firing'said chamber to an elevated temperature comprising burners positioned in the side walls of said chamber adjacent to the side having said slot therein and between which the sides of the portion of the work projected into said chamber are located, and means to drive said conveyor mechanism to transport the work pieces downwardly through the chamher, said conveyor mechanism including means operable to discharge the work pieces therefrom after the latter pass from the bottom opening of the chamber.

5. Heat treating apparatus comprising structure providing a vertically extending refractory lined chamber which is open at the top and bottom and slotted at aside'wall thereof, means for firing said chamber to an elevated temperature comprising opposed burners in the side walls of said chamber adjacent to the side having said slot therein, conveyor means adjacent to the chamber including an up-run side and a downrun side for carrying and vertically transporting in spaced apart relation horizontally disposed elongated work pieces to be heated at an end thereof, said conveyor means being positioned with respect to said structure so that the ends of the work pieces to be heated project into the chamber through the slotted wall thereof and in between said burners, means to drive said conveyor means in a direction so that said work pieces enter and leave the chamber through the openings at the top and bottom, respectively,

the down-run side of the conveyor means includ leave the conveyor means at about the same time. I

6. Heattreating apparatus comprising structure providing a vertically extending refractory lined chamber having end openings at the top and bottom and a slotted sidewall, conveyor means adjacent to said chamber for carrying and vertically transporting elongated work pieces to be heated at an end thereof, said conveyor means being positioned with respect to said structure so that the ends of the work pieces to be heated project into the chamber through the slotted wallthereof during vertical transport and enter.

and leave the chamber through the end openings, means for firing said chamber to an elevated temperature, comprising opposed burners positioned in the walls of said chamber adjacent to the'wall having said slot therein and between which opposite sides of the portions of the work pieces projecting into said chamber are located as they move through said chamber, and means comprising movable members at the top of said structure at the vicinity of the end opening for adjusting the size of such opening to accommodate work pieces of different size.

7. Heat treating apparatus comprising structure providing a vertically extending refractory lined chamber having end openings at the top and bottom and a slotted side wall, conveyor means adjacent to said chamber for carrying and vertically transporting elongated work pieces to be heated at an end thereof, said conveyor means being positioned with respect to said structure so that the ends of the work pieces to be heated project into'the chamber through the slotted wall thereof during vertical transport and enter and leave the chamber through the end openings, means for firing said chamber to an elevated temperature, comprising burners positioned opposite the ends of the work pieces as they move through said chamber, vertically extending hollow jackets at the side wall at 0pp0-' site sides of the slot therein, said jackets having inlets and outlets for circulating a coolant therethrough, and means including adjustable plate members overlying said jackets for varying the Width of the gap formed therebetween at the region of the slot.

FREDERIG O. HESS.

FRED MAUD.

EDWIN F. STOERTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 7 Name Date 1,252,561 Fassinger Jan. 8, 1918 1,782,451 7 Waisner Nov. 25, 1930 1,782,481 Shipley et a1. Nov. 25, 1930 1,920,691 Frischkorn Aug. 1, 1933 2,182,294 Kuhnle Dec. 5, 1939 2,288,098 Mason June 30, 1942 2,371,161 Felber Mar. '13, 1945'

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