US1341299A - Furnace and lining therefor - Google Patents

Description

1. P. COPLAND.

FURNACE AND LlNlNG THEREFOR.

APPLICATION FILED AUG-l0, I918.

I 1,341,299, Patented May 25,1920.

17 Z1 s 5 Z0 v V 1! .1 /A

UNITED STATES PATENT OFFICE.

JAMES P. COPLAND, OF SOUTH EUCLID, OHIO, ASSIGNOR TO THE ELYBIA IRON AND STEEL COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

FURNACE AND LINING THEREFOR.

Specification of Letters Patent.

Patented May 25, 1920.

To all whom it may concern:

Be it known that I, JAMES P. COPELAND, a citizen of the United States, residing at South Euclid, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Furnaces and Linings Therefor, of which the following is a full, clear, and exact description, reference being had to the accompanying drawin s.

%his invention relates to furnaces and especially to such furnaces as are subjected to high degrees of temperature for lon periods as in metallurgical works, althoug not limited to this use as I shall hereafter show. The object of the invention is the provision of a furnace of such construction and lined with such material as to withstand elevated. temperatures practically indefinitely without burning out, warping, cracking or otherwise deteriorating as has always heretofore been the case.

The essence of my said invention consists in linin such a furnace with a metallic alloy containlng a preponderance of one or more iron group metals together with a considerable percentage of chromium, with or without other metals of the chromium group. By iron group metals I means the metals iron, manganese, cobalt and nickel; and by chromium group metals I means the metals chromium, molybdenum and tun sten.

The iron group metal which preferably employ in preponderating amount is iron owm to its comparative cheapness, though nicke appears to be equally effective in most cases and its use in considerable proportion is im eded only by its high cost. I he quentl and in fact preferably, alloy the iron with a small roportion of nickel since this mixture affor s a considerable elevation of the melting point, decreases the tendency to warp on heating, and affords a degree of resistance to oxidation. I ordinarily employ nickel up to a lproportion of about 4 or 5 per cent. althoug its use u to about 20 per cent. produces a superior a loy.

Manganese may also advantageously be added since it v ssesses a peculiarly marked effect in elevatm the melting point and increasing the har ness of iron and its alloys.

It also has a beneficial influence in preventing oxidation of the iron. I have generally employed the same only in small quantities, for example about 1.5%, but do not confine myself thereto.

The main advantage imparted by the chro nlum flows from the adherent and i1npervious character of its oxid which serves as a protective coating shielding the metal therebeneath; although it is also of advantage in raising the melting point of the alloy, decreasing its coefficient of expansion, and reducing its tendency to warp and twist with changes of temperature. I preferably employ this material within the limits of 10 an 40 per cent. by weight, since below 10 per cent. its shielding effect becomes decreased and the melting point of the alloy becomes too low, while above 40 per cent. the cost of the alloy is rendered unnecessarily high.

ungsten may also be used in the alloy per cent.

A s an example of a very satisfactory ma terial for use in my invention I will cite the following analysis:

Silicon .17 Sulfur .026 Phosphorus .042 Carbon; .66 Vanadium; .18 Tungsten .92 Manganese 1.47 Nickel 4.87

Chromium 18.60 Iron 72.95

Such an alloy will not warp or twist even with repeated heating; will not melt or even soften at any temperature up to the melting point of. iron; will not become oxidized at any temperature short of its own melting point; and has a coeflicient of expansion within the limits of those of firebrick wherefore it does not tend by its changes in size to wreck the casing or shell with which it is ordinarily surrounded.

Such an alloy is most conveniently made in the electric furnace, but the particular method of making the same has no bearing upon the present invention, since it will be understood that the alloy could perfectly well be made by melting the pure constituents by suitable means such as in an electric use by casting in a suitable mold, since rollmg is impossible, at least when cold, and

machining is very slow and expensive. The material may either be cast in the completed form of a finished furnace lini or may be made in the form of plates WlllCll are subsequently bolted or otherwise secured together; and may either expose its outer slde to the air or to other gases, or may be surrounded and backed up by firebrick, magnesia, asbestos, gypsum, sand, or other suitable or convenient material.

This construction may be used for muffle furnaces, crucible furnaces, anneallng furnaces, re-heating furnaces, heat-treating furnaces, hardening furnaces, rlvet heaters, welding and forging plants, steam boiler furnaces, bakers furnaces, and all other types of heated devices either for metallurgical plants, iron works, glass works, pottery works, blacksmith shops, garages, shipyards, repair shops, bakeries, or other places where heating is done, and may be used with gas, coal, coke, oil or electricity.

In the drawing accompanying and forming a part of this application Figure 1 1s a cross-sectional view through a simple small furnace embodying my invention; Fig. 2 1s a longitudinal sectional view of a part of a different type of furnace constructed in accordance with my invention; and Fig. 3 1s a cross-sectional view of another type of furnace constructed in accordance with my improvements.

Referring first to Fig. 1, 1 represents the metallic lining which ishere shown as cast in a single piece and having at one side the aperture 2; 3 represents a casing or shell of brick or the like structural material built therearound and preferably spaced from the exterior of the lining to provide a space 4 which is filled with some soft refractory packing 5 such as ma nesia, sand, gypsum, asbestos or the like, w 'ch serves to fill any inequalities in the adjacent walls, to conserve the heat inside the furnace, to shield the casing from undue temperature, and to form an elastic or yielding layer which shall take up strains and permit the relative expansion and contraction of the parts without injury thereto. The casing 3 is shown as provided with an aperture 6 in alinement with the aperture 2 and receiving a tube 7, which may conveniently be of the same material as the lining 1 and permit the admission of the heating element, which may be incandescent gases produced by a combustion exterior of the furnace or may be any inflammable mixture to be burned inside the furnace. a

In case the furnace be of small size it is possible and in fact customary to close the openin more or less by means of firebrick so pile as to permit the escape of any waste gases or combustion products, but in case the furnace be of larger size it is sometimes convenient to provide a more elaborate closure, as will be well understood by those skilled in the art. In an electrically heated furnace no opening is necessary for the discharge of any burned gases, but only a suitable aperture or apertures for the passage of the conductors.

In Fig. 2 I have illustrated a mufiie furnace wherein 15 represents a furnace lining as hereinbefore described, which is here shown integral with the inlet tube 16 and with the flue linin 17. The furnace lining is here shown as of double-wall construction providing a mufile chamber 18 whose top may be either open so that the hot gases can sweep therethrough or closed by a lid 19, either integral or removable as desired. This mufile furnace is as before provided with a shell 3 and with a refractory packin 5.

In Fig. 3 I have shown a furnace of larger size suitable for a great number of purposes such as annealing glass or metal articles, heat treatment, cementation, case hardening, etc. In this embodiment the lining is composed of a plurality of separate plates 2020 of the resistant metal herein described, each of the plates bein formed with marginal flanges 2121 and t e flanges of adjacent plates being suitably fastened together as by bolts or pins. It will also be understood that the flanges of adjacent plates can be so fashioned as to interfit, thus dispensing in whole or part with the necessity of independent fastenings. The various plates can be made of any suitable or convenient shape, but are preferably substantially standard in shape and size so that a large number of different furnaces can be built with a small number of patterns. This lining as before, is preferably surrounded by a shell 3 and packing 5, and can be heated in any suitable manner as heretofore explained.

It will be understood that these drawings are illustrative only and not limiting; that the forms and constructions in which In invention can be embodied are almost limitless; that I do not restrict myself to a construction involving a spaced outer shell in combination with the lining and an intervening space to be filled with unformed material, but merely present that as being a cheap and satisfactory construction; and that in general I do not limit myself except as recited in the claims hereto annexed or rendered necessary by the prior state of the art.

Having thus described my invention, what claim is 1. A cast metal furnace lining consisting of an alloy containing from to per cent. of iron and 15 to 25 per cent. of chromium, the remaining consisting principally of other metals from the iron and chromium groups.

2. In a device of the character described, the combination with a firebrick of a cast metal lining consisting princi a y of a metal or mixture of metals oft e iron group alloyed with chromium, the iron group metal bein preponderant and the allo having a coe 'cient of expansion within t e limits of that of firebrick.

3. A cast metal furnace lining consisting approximately of manganese 1% per cent., nickel 5 per cent, tungsten 1 per cent, chromium per cent. and the remainder principallx iron.

4. furnace having incorporated therein a multiple walled lining composed of a metallic alloy containing one or more iron group metals alloyed with 5 to per cent. of chromium.

5. A cast metal furnace lining composed of an alloy comprising the ma or portion of iron, and the remainder of metals from the iron and chromium groups.

6. A cast metal furnace lining consisting of an alloy containin to 7 5 per cent. of iron, 15 to 25% of c romium, and the remainder of a metal from the iron group.

In testimony whereof, I hereunto aflix my signature.

JAMES P. COPLA ND.

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