US1919054A - Furnace - Google Patents

Description

July 18, 1933. COPE AL 1,919,054

FURNACE Original Filed March 16, 1929 4 Sheets-Sheet l o 1 I ygvvuentow Fran/i 7. Cape Bag 0. Oyxler 4, I M ammo VII July 18, F T OPE ET AL 1,919,054

FURNACE Original Filed March 16, 1929 4 Sheets-Sheet 2 3140a "nfow Fran/i 7. Cape w i Ray C. Oysler (1 30 new July 18, 1933. F. T. COPE ET AL- FURNACE Original Filed March 16, 1929 4 Sheets-Sheet 3 Fran/i T 60 06 Bay 6. Oyster Patented July 18, 1933 UNITED STATES PATENT OFFICE FRANK T. COPE AND RAY 0. OYSTER, 0F SALEM, OHIO, ASSIGNOBS TO THE EEC'IBIC FURNACE COMPANY, OF SALEM,

OHIO, A CORPORATION OF OHIO FURNACE Application filed March 18, .1929, Serial No. 347,706. Renewed December 2, 1888.

This invention relates to electric heat treatment furnaces wherein a moving conveyer is used to convey the objects to be heated, said conveyer being adapted to support the Objects on its upper surface, carry them through the heated chamber, and discharge them at the desired point, preferably at or near the termination of the chamber.

it at the point where material is loaded.

Another object is to providemeans whereby objects are prevented from falling from the conveyer during its travel through the chamber and means for discharging the heated objects without damage.

We use a conveyer consisting of a plurality of links which are assembled to form an endless conveyer of any desired width and length by the use of rods. These rods have heads, preferably formed integral with the rods, of such size that they may be thrust through the openings in the links. When the conveyer is stretched taut, however, the removal of these rods is prevented.

We make the upper or carrying surface of these links curved with a radius equal to the distance from the center of the conveyer drums or sprockets in order that the conveyer may have a smooth cylindrical surface where it travels around the sprockets.

It will be seen. that such a conveyer comprises an articulated link belt of small elements and has a degree of flexibility much greater than the usual construction in which the carrying portion is composed of relatively large,'substantially flat flights or plates.

It will also be seen that such a conveyer is very strong in tension because of the large number of shearing surfaces which resist failure of the conveyer; and that the multiplicity of small elements forms a lon tudinally and laterally continuous and retlcular endless belt which will stand high temperatures without injurious warping.

For drivin and maintaining tension in our improve the form of toothed drums having teeth of substantially the shape shown in the drawmgs. The leading face of each tooth is formed with a portion sloped upward with respect to a line tangent to the drum and is thus made to support the end portion of a link. The rows of teeth are staggered and each row of links is supported at intervals equal to the tooth spacing, intermediate links being carried by the rods. We make the form of the tooth faces such that the center portions of the links do not bear against the drum, thereby avoiding stresses tending to bend the links.

An embodiment of the invention is illuw Fig. 2,,a transverse vertical section through" the furnace;

Fig. 3, a fragmentary lan view of a portion of the improved chain belt upon an enlarged scale;

Fig. 4, a detached perspective view of one link of the chain belt;

Fig. 5, a detached perspective view of one of. the toothed drums;

Fig. 6, an enlarged fragmentary view of a portion of one toothed drum, showing the manner in which the chain belt travels over the same;

Fig. 7, a view of two adjacent links of the chain belt, showing the manner of placing a pivot rod through the same for assembling or repairing the chain;

Fig. 8, an elevation of one of the pivot rods;

Fig. 8a, a similar view of a modified form of pivot rod;

conveyer we use sprockets in- Fig. 9, an edge elevation of a portion of the chain belt;

Fig. 10, a fragmentary plan view of a modified form of conveyer belt;

Fig. 11, a detail perspective View of one of the links with wings at its sides;

Fig. 12, an elevation of a modified form of furnace embodying means for driving both sprocket drums;

Fig. 13, a section taken substantially upon the line 13-13, Fig. 12, showing the friction clutch;

Fig. 14, a detached sectional view of the friction clutch and means for driving the tail sprocket; and

Fig. 15, a fragmentary sectional view showing details of the supporting members disposed on the supporting structure.

Similar numerals refer to similar parts throughout the drawings.

The furnace or kiln in which the improved conveyer is located may be of any suitable construction, comprising refractory floor or bottom wall 10, the side walls 12, roof or arch 14, and rear doorway 43, normally closed as by the door 13.

The entrance end of the furnace may be provided with the charging opening 15, arranged to be normally closed, as by the sliding door 16, while the discharge end of the furnace may be provided with an inclined chute 17, for receiving articles from the conveyer and discharging them from the heating chamber as to a quenching tank 44.

The chute 17 may be of air-tight construction and may terminate beneath the level of the quenching fluid in the tank 44, so as to prevent cooling of the furnace by air currents.

The improved conveyer is in the form of a I chain belt indicated generally at 18 and made up of a series of links 19, each of which is substantially the shape shown in Fig. 4, having the substantially flat under side 20 and the arcuate upper side 21 joined at their ends by the rounded portions 22 and preferably braced or reinforced intermediate their ends as by the vertical web 24.

The upper or carrying surfaces of these .inks are curved upon a radius equal to the distance from the center of the conveyer drums or sprockets, in order that the chain belt may have a smooth cylindrical surface as it travels around the drums.

These links are located in staggered rows and connected together by the pivot rods 25, forming a chain belt of any desired width and length as best illustrated in Figs. 1 and 3.

This belt is arranged to be located over similar sprocket drums 26 and 27 located at the inlet and discharge end portions, respectively, of the furnace, each drum being provided with spaced rows of sprocket teeth 28 coinciding" with the spaces between the belt links for-registering engagement between the links 19 of the chain belt.

The teeth' 28, upon the drums, are of substantially the shape best illustrated in Fig. 6 of the drawings. The leading face of each tooth is formed with a portion 28, sloped upward with respect to a line tangent to the periphery of the drum, for the purpose of supporting one end portion of each link as it engages with the tooth.

The rows of teeth are staggered, and each row of links is supported at intervals equal to the tooth spacing, intermediate links being carried by the rods 25. It will be seen that the teeth are so shaped that the center portions of the links do not bear against the drum, thereby avoiding stresses tending to bend the links.

For the purpose of preventing small articles from falling from the conveyer belt, side guards 19' may be formed along the edge portions of the links at each side edge of the conveyer, as shown in Fig. 3.

When small articles are to be handled, which might partially or wholly drop through the openings in a conveyer as shown in Figs. 3

and 4, a modified form of link, as shown in Figs. 10 and 11, may be employed.

A substantially closed carrying surface is produced upon the conveyer belt, by forming the arcuate upper surface of each link with wing portions 42. Side guards 45, similar to the side guards 19' in Fig. 3, may be employed on the side edge links to prevent articles from falling from the conveyer.

When links of the modified form shown in Figs. 10 and 11 are used, it will be seen that the wings prevent placing adjacent links in the position shown in Fig. 7, for the purpose of inserting the ivot rods shown in Fig. 8.

A modified form of pivot rod is therefore provided, which may be as shown in Fig. 8a, comprising a shank portion 46, an integral head 47 at one end thereof, and a removable head 48 at the other end, adapted to be held in place as bv'the locking pin 49.

' Each sprocket drum may be provided with trunnion portions 29 adapted to be carried in suitable journals. The trunnions of drum 27 may be journaled in fixed-brackets 50, and those of the drum 26 in the lower ends of swinging arms 51, which are fixed to a shaft 52, carried by the brackets 53.

The shaft 52 may be operatively associated with any suitable means such as a counterweight for maintaining tension in the conveyer.

For driving the drum 27 we may form one of the trunnion portions 29 with a square hole extending therethrough and adapted to operatively engage a squared end portion of the driving shaft 29'. This shaft may extend through the side wall of the furnace, as in Fig. 2, and have fixed thereon a sprocket Wheel, or the like, as indicated at- 30, for con- 5 squared end of the shaft 29', form a wabbler coupling which permits misalignment of the drum 27 and the shaft 29', and also permits the removal of the shaft or drum without tearing the furnace apart.

A modified arrangement, using the improved conveyer, above described, is shown in Fig. 12. The purpose of this modified form is to prevent heat losses due to convection currents of air through the furnace, and

5 to provide auxiliary driving means so as to reduce the tension to which the conveyer is subjected when driven from a single point.

By reference to Fig. 1, it will be seen that the discharge chute 17 emerges from the furnace at a lower level than the opening resulting when the door 16 is raised.

In practice it is often impracticable to seal the end of the chute 17, beneath the level of the quenching bath, as shown in Fig. 1, and

5 1 current of cold air will rise through the chute 17, thereby chilling the interior of the furnace at the discharge end, and causing heat to be wasted.

To overcome this difiiculty, we incline the furnace upward toward the dischargeend,

as shown in Fig. 12, at such an angle that the end portion 54 of thechute 17 is at substantially the same level as the bottom of the charging door 16.

In order to reduce the tension in the conveyer when it is driven from a single point, we may employ an auxiliary drive, operatively connected to the sprocket drum 26, and shown generally in Fig. 12, and in detail in Figs. 13 and 14.

This auxiliary drive embodies a sprocket driving a sleeve 56 on the shaft 52 by suitable friction means. Another sprocket 57 is fastened to the sleeve 56 and drives the drum 36 through the chain 59 and sprocket 58.

The sprocket 55 is preferably made to rotate at a slightly faster rate than the sprocket 30, thus. tending-to cause the drum 26 to rotate more rapidly than the drum 27.

The drums 26 and 27, being connected by the conveyer belt, can only operate at the same speed, and hence the friction means, on the sleeve 56, allows relative movement between the sprocket 55 and sleeve 56, result- 38 at the entrance or charging end of the furnace, the door 16 being first raised sufficiently to permit the articles to pass beneath the same as they are fed into the furnace and disposed upon the belt.

This construction provides an insulated enclosure for the tail sprocket drum, at the same time permitting for convenient loading of articles or material to be treated, while retaining the heat in the conveyer.

As the articles disposed upon the belt reach the discharge end portion of the furnace, they will be stripped or removed from the conveyer belt by means of the stripper plat-e 31, mounted for pivotal movement with respect to the belt as at 31a, which plate 31 may be located in alignment with the discharge chute 17, terminating at a point adjacent to the sprocket wheel 26 and floating upon the chain belt as shown in Fig. 1. Thus the stripper plate 31 rides upon the chain belt so as to insure removal of the smallest articles therefrom, but its floating action due to its pivotal mounting prevents it from interfering with the forward movement of the chain.

For the purpose of heating the material upon the belt, electric resistors 32 may be supported from the roof of the furnace, and other resistors 33 may be located between the upper and lower strands of the conveyer belt, being supported as upon the insulation or refractory blocks 34: mounted upon inverted T-shaped or L-shaped beams 35 supported from the side walls'12, and in turn supporting the members 36 upon which the upper strand of the conveyer chain slides.

With this arrangement it will be seen that resistors may be located or disposed both above and below the material or articles carried upon the conveyer belt, thus uniformly heating the articles as they pass through the furnace or kiln.

Thus a'partition structure is provided between the drums and between the upper and lower .strands of the chain belt which forms a combined resistor supporting and chain supporting means. This being an open partition structure, scale which drops from the articles or material on the chain belt may pass through the openings in the links and fall through the similar openings in the lower strand of the chain.

A metal return supporting guide 40 may be located upon the floor of the furnace for the lower strand of the chain to ride upon, and a scrap pocket 41 may be located at the end of this guide to receive the scale and dirt which are carried back by the chain. Any suitable means may be provided forcleaning out this pocket.

As shown in Figs. 10 and 11, each link of the chain may be provided with wings 42, at its sides, thus forming a reticular belt conveyer in which the links are close enough to be specially adapted for conveying a continuous layer of very small articles, but with a sufficient interval between the links and the articles to permit a flow of heat upward or downward through the same, as may be desired, for uniformly heating the layer of small articles on the conveyer.

The sprocket drums, as well as the chain belt, may be made of suitable heat resisting metal to permit the same to stand the high temperatures to which they are subjected. The particular link construction of the chain belt provides sufficient flexibility of the same and also makes a construction which is easily operated by means of the sprocket drums for passing the material through the furnace while the stripper plate automatically removes the treated articles from the conveyer belt and discharges them through the chute to the exterior of the furnace.

Moreover, the articulated links, which form a longitudinally and laterally continuous and reticular endless belt, are so small in size, that any warping or bending of any individual links which may result from high heat and varying temperatures, is so slight in each link that theshape of the belt as a whole and its operation around the drums are not materially affected.

For the purpose of cleaning any deposit of scale and dirt from the resistors and hangers, openings, as shown at 60, may be providedin the side wall of the furnace to permit an air pipe to be inserted therethrough and turned to any desired position to blow the scale and dirt from these parts.

In the operation of the improved furnace,

I the upper conveying portion of the longitudinally and laterally continuous endless belt, which extends around and conforms to the shape of the drums at each end of the furnace, forms a continuously moving floor or hearth upon which small metal parts or articles fed into the furnace through the charging opening, are distributed and disposed in a comparatively thin longitudinally and laterally continuous mass or layer, and permits the individual pieces to be uniformly heated, not only with respect to each other, but with respect to each piece, by the heating means located above and below the same.

It is impossible to obtain such a uniformity of temperature by heating small parts in segregated masses or batches in trays or troughs, because of the size of the mass; and the consumption of heat required to raise and maintain the temperature of the containers, decreases the efficiency of the furnace.

Moreover, the amount of oxidation or scale formation is a function of the length of time the parts are exposed to oxidizing influence, and in the improved furnace, the application of heat is applied so directly from above and below the continuously moving mass or layer of small parts, and they are heated to the critical temperature so quickly, that no excessive oxidation or scale is formed before they are delivered into the quenching medium.

In the improved furnace, the small parts are disposed in a continuously moving comparatively thin mass or layer, and are given a gradually applied uniform heat treatment with an adjustable heating cycle under full control, and without the formation of scale or objectionable oxidation, and the small parts are delivered individually to a quenching tank chute without any distortion or nicking, all with the maximum efficiency and a minimum amount of labor and consumption of electric current for obtaining the desired quality of product.

And finally, the improved furnace has successfully supplied a need and a demand which has existed for many years for a type of furnace which would successfully handle and heat treat small parts, and would produce one hundred percent of netmaterial; and that problem was never solved until the new type of furnace illustrated anddescribed herein was devised, and the improved functions and results set forth herein were never before obtained in any prior furnace.

The reticular belt conveyer which is described but not claimed herein is made the subject matter of a divisional application filed November 16, 1929, Serial No. 407,618.

We claim:

1. In a furnace, a conveyer belt for carrying articles to be heated, a floating stripper plate adjacent to the discharge end of the belt for automatically removing articles from the belt, a quenching tank, and a closed chute communicating with the stripper plate and terminating beneath the level of the quenching bath.

2. In a furnace, a conveyer belt for carrying articles to be heated, a stripper plate mounted for pivotal movement relative to the belt and adjacent to the discharge end of the belt for automatically removing articles from the belt, and a closed 'chute communicating with the stripper plate.

3. In a furnace, a conveyer belt for carrying articles to be heated and inclined upward from the charging end of the furnace toward the discharge end thereof, a charging door at the charging end of the conveyer and a discharge chute at the discharge end thereof, the discharge end of the chute being on substantially the same level as the charging door.

4. In a furnace, a conveyer belt for carrying articles to be heated, a floating stripper plate adjacent to the discharge end of the belt for automatically removing articles from the belt, and a chute operatively associated with the stripper plate for discharging the articles from the furnace.

5. In a furnace, a conveyer belt for carrying articles to be heated, a stripper plate mounted for pivoted movement adjacent to the discharge end of the belt for automatically removing articles from the belt, and a dis charge chute operatively associated with the stripper plate for discharging the articles from the furnace.

6. In a furnace, a conveyer belt for carrying articles to be heated, a stripper plate adjacent to the discharge end of the belt for automatically removing articles from the belt, and a chute for discharging the articles from the furnace, said stripper plate being pivotally mounted in operative relation to said chute and having one edge supported by the article-carrying surface of said conveyer belt.

7. An electric furnace comprising refractory walls, a rotatable drum mounted within said walls adjacent each end thereof, a horizontally extending supporting structure between said drums, supporting members disposed on said supporting structure above and on the bottom wall below said supporting structure, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by said drums and supported by said supporting members and con vorming to the shape of said drum,

registering engaging means between the belt and the drums, heating elements disposed within said refractory walls above said conveyer, a charging aperture located adjacent one end of said conveyer, and heating elements disposed on said supportin structure beneath the conveying portion 0 said conveyer, for the uniform heat treatment of articles disposed on said conveyer through said charging aperture.

8. An electric furnace comprising refractory walls, a rotatable drum mounted within said walls adjacent each end thereof, a horizontally extending supporting structure between said'drums, supporting members disposed on said supporting structure above and on the bottom wall below said supporting structure, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by said drums and sup orted by said supporting members and con orming to the shape of said drum, heating elements disposed within said refractory walls above said conveyer, a charging aperture located adjacent one end of said conveyer, and heating elements disposed beneath the conveying portion of said conveyer, for the uniform heat treatment of articles disposed on said conveyer through said charging aperture.

9. A heating furnace having refractory walls, a rotatable drum mounted within the walls adjacent each end of the furnace, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by the drums entirely within the walls, a horizontally extending structure between the drums comprising supporting members thereon for the conveying portion of the belt, supporting means for the return portion of the belt, a charging opening located adjacent to one end of the con veyer, and heating means located above and below the conveying portion of the endless belt, for the uniform heating of articles fed through the charging opening and disposed in a longitudinally and laterally continuous layer on the conveying portion of the belt.

10. A heating furnace having refractory walls, a rotatable drum mounted within the walls adjacent each end of the furnace, a flexiblearticulated longitudinally and laterally continuous and reticular endless belt conveyer carried by the drums entirely within the walls, registering engaging means between the drums and the belt, supporting members below the conveying portion and the return portion of the belt, a charging opening located adjacent one end of the conveyer, and heating means located above and below the conveying portion of the belt, for the uniform heating of articles fed through the charging opening and disposed in a' longitudinally and laterally continuous layer upon the conveying portion of the belt.

11. A. heating furnace having refractory walls, a rotatable drum mounted within the walls adjacent each end of the furnace, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by the drums entirely within the walls, supporting members below the conveying portion and the return portion of the belt, a charging opening located adjacent one end of the conveyer, and heating means located above and below the conveying portion of the belt, for the uniform heating of articles fed through the charging opening and disposed in a longitudinally and laterally continuous layer upon the conveying portion of the belt.

12. An electric furnace having refractory walls, a rotatable drum mounted within the walls adjacent each end of the furnace, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by the drums entirely within the walls, registering engaging means hetween the drums and the belt, supporting membersbelow the conveying portion and the return portion of the belt, a charging opening located adjacent one end of the conveyer, and heating elements located above and below the conveying portion ofthe belt, for the uniform heating of articles fed through the charging opening and disposed in a longitudinally and laterally continuous layer upon the conveying portion of the belt.

13. An electric furnace having refractory walls, rotatable drum mounted within the walls adjacent each end of the furnace, a flexible articulated longitudinally and laterally continuous and reticular endless belt conveyer carried by the drums entirely within the walls, supporting members below the conveying portion and the return portion of the belt, a charging opening located adjacent one end of the conveyer, and heating elements located above and below the conveying portion of the belt, for the uniform heating of articles fed through the charging opening and disposed in a' longitudinally and laterally continuous layer upon the conveying portion of the belt.

14. A heating furnace comprising refractory walls,.a rotatable drum mounted within said walls adjacent each end thereof, horizontally dis osed supporting members between said rums, a flexible longitudinally and laterally continuous and reticular belt conve or carried by said drums and suprte by said supporting members and conormin to the shape of said drums, and means or heating the furnace within said Y refractory walls above and below the conveying portion of said conveyer, for the uniform heat treatment of articles disposed on said conveyor.

15. A heating furnace comprising refractory walls, a rotatable drum mounted within said Walls adjacent each end thereof, horizontally disposed supporting members between said drums, a flexible longitudinally and laterally continuous and reticular belt conveyer carried by said drums and supported by said supporting members and conforming to the shape of said drums, and means for heatin the furnace within said refractory walls a ove the conveying portion of said conveyer, for the uniform heat treatment of articles disposed on said conveyer.

16. A heating furnace comprising refractory walls, a rotatable drum mounted within FRANK T. COPE. RAY 0. OYSTER.

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