US1768776A - Rotary heat-treatment furnace and lining for same - Google Patents

Description

y 1,1930- E. H. MIX 7 1,768,776

ROTARY HEAT TREATMENT FURNACE AND LINING FOR SAME Filed Feb. 8, 1929 3 Sheets-Sheet l E. H. MIX 1,768,776

3 Sheets-Sheet 2 Filed Feb 8, 1929 ROTARY HEAT TREATMENT FURNACE AND LINING FOR SAME Jul 1, 1930.

July 1, 1930. E. H. MIX 41,768,776

ROTARY HEAT TREATMENT FURNACE AND LINING FOR'SAME Filed Feb. 8, 1929 3 Sheets-Sheet 3 Patented July 1, i930 e sures rATEN'r EDWARD H. MIX, OF ROCKY RIVER, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO REPUBLIC STEEL CORPORATION, A CORPORATION OF NEW JERSEY ROTARY HEAT-TREATMENT FURNACE AND LINING- FOR SAME Application filed February 8, 1929. Serial No. 338,349.

This invention relates. to heat-treatment furnaces, and more particularly to the linings of such furnaces.

Furnaces of the type to which this invention relates are composed of an inner metallic lining, a covering of refractory material,

such as masonry, for such lining, and an outer metallic shell enclosing the masonry, the lining being composed of a plurality of sections arranged end-to-end and forming a cylindrical heat-treatment chamber through which the articles to be heat-treated are conveyed by means of a screw thread formed upon the interior of the lining sections, the

furnace being rotated during the operation.

Furnaces of this type have been subject to the objections that, due to the strains set up by the heating and cooling, the lining will lose its shape, as through warping, twisting,

go or breaking, such breaking occurring frequently at the base of they threads. It has been proposed to cure the breaking or cracking of the threads by notching the same in the various sections, thereby destroying the continuity of such threads, but this has not entirely overcome the defect. It has also been proposed to align the sections of the lining by providing them with interlocking end recesses and projections. This, however,

39 has resulted in the setting up of uneven strains in the sections, due to the heating and cooling to which they are subjected in the operation of the furnace; also in the breaking and loosening of the masonry applied to the exterior of the lining sections.

The general purpose and object of the invention is to provide a furnace of the character referred to which is so designed as to be inherently heat-resistant and one'wherein the sectionsof which the lining is composed are, because of their design, .enabled to withi stand repeated and prolonged heating, with subsequent cooling, without losing their shape, either through warping, twisting or breaking, and to accomplish this result irrespective of the material of which the sections are made, thereby enabling such lin-' ings to be produced successfully from much lower-priced materials than have been employed heretofore in linings of similar type.

to enable the sections to be assembled in such manner as to preserve the continuity of the screw thread throughout the lining as a whole. Further and more detailed objects of the invention will appear hereinafter and will be realized through the construction and arrangement of parts shown in the drawings, wherein Fig. 1 represents aside elevation of a furnace embodying my invention, the furnace shown in such view being of the wellknown Rockwell type; Fig. 2 a central longitudinal sectional View through said furnace; and Figs. 3, 4, 5, 6, 7 and 8 are details in section corresponding respectively to the lines 3--3, 4- 1, 5-5, 6-6, 77 and 88 of Fig. 2, and looking in the directions of the arrows.

Describing the various parts by reference characters, the furnace comprises an outer shell A, of any suitable metal, having therein a lining consisting of a plurality of intermediate sections B and end sections C, D and E, there being interposed between the lining and the outer shell the annular covering F for the lining, the said covering consisting of brick or other suitable refractory heatresistant material. The lining section D is adjacent to the front or receiving end of the furnace, which end is provided with a frusto-conical extension G of the outer shell into which the articles to be heat-treated (such as bolts) are delivered and whence these articles in turn are delivered into the lining section D. The opposite end of this shell has secured thereto a sleeve H which receives a burnerv (not shown) the flame and products of combustion wherefrom are delivered into the lining.

The shell is provided with bands I and K extending therearound and constituting circular tracks by which the furnace is supported upon rollers arranged on opposite sides of the axis of the shell, the rollers L, L on one side being connected by a shaft M having a worm M thereon meshing with a worm gear N on a shaft N which may be driven b a motor 0. The rollers on the opposite si e are the ordinary idle rollers, and are not shown. The lining section E is provided with a delivery outlet S registering with a spout S which extends through the furnace wall,.the spout being surrounded by a hollow collecting'ring P.having a delivery spout P. The outer shell, with the extens1ons G and H and its collecting ring P, P and the means for rotating the shell, are old and well known in the art, being of the standard Rockwell type, and, in their details, form no part of the invention herein.

Referring again to the extension G of the shell A, it will be seen that this extension is provided with an opening G through which the objects to be heat-treated are dumped or otherwise inserted into the said extension and are picked up, as the furnace is rotated, by the lateral opening G3 in a hopper G and delivered by the inclined bottom G of said hopper through an opening R in a plate R covering the front or receiving end of the furnace and thence into the first section D of the lining. This construction of the charging end of the furnace is also well known.

The lining section D is provided with a high thread D extending around the interior thereof, two complete turns of such thread being shown.

Section E, at the opposite or delivery end of the lining is provided with about 1 turns of a thread E, the thread being preferably the same height as the thread D and having its delivery end merging with the out let E.

Adjacent to the rear end of the section D and adjacent to the front end of the section E are the sections G, C, each being provided with one turn of a thread C, the said thread being preferably of the same height as the threads D and E; and the threads C, C and E are notched, as shown at C C and E to minimize, as far as possible, the action of strains upon said threads due to the heat ing and cooling of the parts.

Four sections B are shown as interposed between the sections C, C. Each of the sections B comprises, in addition to the outer cylindrical wall, a single turn of a thread B, the said thread being of much less height than the threads C, C, D, and E; and each of the sections B is provided in addition with a rib B extending parallel with the axis of rotation of the lining and connecting the parts of the thread B which are adjacent to the ends of such sections, thus reinforcing each section at its weakest points-where the thread runs off or merges with the ends thereof The ribs B are in alignment, Similar reinforcement is provided for the sections C, C, by means of the ribs Q which ribs are arranged to align with the ribs 13.

Each of the sections B, C, D and E is provided with a plurality of external radially extending ribs B C, D and E respectively. Three such ribs are shown on each section, and they are spaced apart preferably 120 degrees, thereby enabling the sections to be assembled in such manner that a continuous thread will be provided throughout the interior of the lining, while providing the lining sections with means whereby they may be interlocked with the covering F.

In operation, the bolts, or other objects to be treated, are inserted into the receiving end G of the furnace and are picked up b the hopper G as the furnace is rotated, eing delivered from the hopper into the receiving section D of the lining. The articles are fed by means of the thread D, C, B and E to the delivery outlet E, being subjected to heat treatment in their travel through the lining.

By reducing the hei ht of the thread B in each of the sections the liability of the said sections to crack, at the bases of the said threads, is reduced to a minimum, due to the reduction of the amount of metal in such threads, and also dueto the smaller amount of metal exposed to direct flame and consequent uneven heating. However, the threads B are of sufficient height to enable all objects remaining in the furnace at the conclusion of the operation to be conveyed through the sections B and delivered to the sections 0 and E, thus insuring the emptying of the furnace at the end of such operation. The provision of the cross ribs B and C strengthens the sections, as pointed out hereinbefore, and also provides means for lifting and stirring up the bolts or other objects in said sections as the furnace is rotated, thereby contributing to the eflicient and more uniform heat-treatment of the objects'in these sections.

As pointed out hereinbefore, the external radial ribs not only provide means which enable the lining sections to be assembled so as to provide a continuous thread running through the entire lining, but they also provide an efiicient means for interlocking the lining with the brickwork or other masonry of the covering F, which mode of interlocking reduces to a minimum the liability of the lining to work within such covering and to disintegrate the latter. Furthermore, while it has been found advisable to notch the threads in the sections, 0, C and E, owing to their height, it is unnecessar to notch the threads in the sections B, there y preserving an unbroken turn of the thread in each section, with the result that the strains set up by the heating and cooling actions are uniform throughout such sections. a

While I have shown and described the furnace lining as consisting of two elongated end sections D and E and two shorter end sections C, G with four short intermediate sections, it will be obvious that the number of the sections may be varied. However, the lining may consist of two end portions, each having a high thread and an intermediate portion having a low thread; and adjacent convolutions of the low thread, at least, will be connected by the longitudinally extending ribs B.

By virtue of the construction and arrangement of the furnace disclosed herein, the furnace will stand up in service for a much longer period of time than other furnaces of like character with which I am familiar, and will do so without the necessity for using, for the furnace lining, the high-priced high heat-resistant material heretofore deemed necessary for this purpose.

Having thus described my invention, what I claim is: A

1. A furnace of the character described comprising a lining, a covering of refractory material for said lining, and a casing for the lining and covering, the said lining having end portions and an intermediate portion, the end portions each being provided with a thread of relatively great height and the intermediate portion being provided with a thread of relatively small height, there being longitudinally extending ribs connecting adjacent convolutions of the thread in such intermediate portion of the lining and the lining being provided with external projections adapted to interlock with the covering.

2. A furnace of the character described comprising a lining, a covering of refractory material for said lining, and a casing for the lining and covering, the said lining having end portions and an intermediate portion, the end portions each being provided with a thread of relatively great height and the intermediate portion being provided with a thread of relatively small height, there being longitudinally extending ribs connecting adjacent convolutions of the thread in such intermediate portion of the linin and each lining portion being provided with a plurality of radially extending ribsadapted to interlock with the refractory covering and to facilitate the assembling of the portions of the lining.

3. A furnace of the character described comprising a lining having end portions and an end intermediate portion, each havin an internal thread therein, a covering of re 'ractory material for such lining portions and ribs in such intermediate portion connecting adjacent convolutions of the thread therein.

4 A furnace of the character described comprising a plurality of lining sections arranged end-to-end and each having an internal thread therein, a covering of refractory material for such lining sections, a rib extending longitudinally of each of such sections and connecting the adjacent convolutions of the thread therein, and one or more ribs projecting from the exterior of each section for interlocking the lining with said covering.

5. A furnace of the scribed comprising a plurality of lining sections arranged end-to-end and each having one or more ribs projecting from the exterior thereof and provided each with an internal thread adapted, when the sections are assembled, to provide a screw thread extending substantially throughout the length of the assembled sections, each section having arib extending longitudinally thereof and connecting the portions of the thread therein adjacent to opposite ends of such section, and a refractory covering for such sections with which the external ribs are interlocked.

6. A furnace lining comprising a plurality of sections arranged end-to-end, each section having an internal thread providing, when the sections are assembled, a screw thread extending substantially throughout the length of the assembled sections, the threads in the end sections of the lining being rela tively high and the threads in the intermediate sections being of materially less height than the threads in such end sections.

7. A furnace lining comprising end sections and a plurality of intermediate sections arranged end-to-end, each section having an internal thread providing, when the sections are assembled, a screw thread extending substantially throughout the length of the assembled sections, each section having a rib extending longitudinally thereof and connecting longitudinally spaced portions of the thread therein.

8. A furnace of the character described comprising a lining composed of a plurality of sections arranged end-to-end each section having an internal thread providing, when the sections are assembled, a screw thread extending substantially throughout the length of the assembled sections, the threads in the end sections of the lining being rela: tively high and the threads in the intermediate sections being of materially less height than the threads in such end sections, a covering of refractory material for the lining, and an outer shell enclosing the said covering, the said furnace being provided with means for delivering articles to be heat-treated into the section at one end thereof and the section at the opposite end of the furnace being provided with an outlet for the delivery of the heat-treated articles, the intermediate sections being provided each with a longitudinally extending rib connecting the portions of the thread therein which are adjacent to the ends of such section.

9. A furnace of the character described comprising a lining composed of a plurality of sections arranged end-to-end, each section character dehaving an internal thread providing, when the sections are assembled, a screw thread of the intermediate portion and connecting extending substantially throughout the adjacent COIlVll1l31OI1S of the thread therein. length of the assembled sections, the threads In testimony whereof, I hereunto affix my in the end sections of the lining being relatively deep and the threads in the intermediate sections being of materially less depth than the threads in such end sections, a covering of refractory material for the lining and an outer shell enclosing the said covering, the said furnace being provided with means for delivering articles to be heat-treated into the section at one end thereof and the section at the opposite end of the furnace being provided with an outlet for the delivery of the Y heat-treated articles, the lining sections intermediate the end sectionsbeing provided each with a longitudinally extending rib connecting adjacent convolutions of the thread therein.

10. A furnace of the character described comprising a lining composed of a plurality of sections arranged end to end, each section having an internal thread providing, when the sections are assembled, a screw thread extending substantially throughout the length of the assembled sections, the threads in the end sections of the lining being relatively high and the threads in the intermediate sections being of materially less height than the threads in such end sections, a covering of refractory material for-the lining, and an outer shell enclosing the said covering, the said furnace being provided with means for de livering articles to be heat-treated into the section at one end thereof and the section at the opposite end of the furnace being pro-vided with an outlet for the delivery of the heattreated articles, the intermediate lining sections being provided each with a longitudinally extending rib connecting the adjacent convolutions of the thread therein, each lining section being provided with a plurality of radially extending external ribs for interlocking the said sections with the refractory covering.

11. A furnace lining comprising a plurality of sections arranged end-to-end, each section having an internal thread, the threads in the end sections being relatively high and the threads in the sections intermediate such end sections being of materially less height than the threads in the end sections, the threads in some of such end sections being notched, and a rib extending longitudinally of each intermediate section and connecting the portions of the thread therein which are adjacent to opposite ends of such sections.

12. A furnace lining comprising end portions and an intermediate portion each having an internal thread, the threads in the end portions being relatively deep and the threads in the intermediate portion being of materially less depth than the threads in the end portions, the threads in such end portions being signature.

notched, and ribs extending longitudinally EDW. H. MIX.

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