US1994637A - Furnace lining and method of preparing same for use - Google Patents

Description

- March 19, 1935. E 1,994,637

FURNACE LINING AND METHOD OF PREPARING SAME FOR USE Filed April 25, 1931 2 Sheets-Sheet 1 *3 i i 7 w F F k i 7 *3 w I i \J I T r3 WVEJ - March 19, 1935. DOYLE 1,994,637

FURNACE LINING AND METHOD OF PREPARING SAME FOR USE Filed April 25, 1931 2 Sheets-sheaf 2 UVEHEf- Patented Mar. 19, 1935 FURNACE LINING AND METHOD OF PREPARING SSAMEY Foa USE GeorgeF. DoyleQElmhurst, 111., assignor to S. Obermayer Company, Chicago, 111., a corpora- .tion of Ohio Application April 25,1931, Serial No. 532,855

4 Claims. (Cl. 25-457) This invention relates to improvements in plase tic furnace-linings, and moreparticularly to'a new and novel method of preparing plastic substantially monolithic furnace lining for use, the

' 5 invention being highly desirable for the lining of. the walls. of practically any kind of combus tion' chamber, lining conduits for hot fluids or flames, etc., although the invention may have many and various uses and purposes as will be apparent to one skilled in the art.

Inthe past, in an endeavor to improve upon the original fire-bricklining for furnaces, fire boxes, or other combustion chambers, a lining of refractory plastic material, such as a compound of. which the major. ingredients were asuitable clay and crushed fire-brick or the equivalents;

was frequently used,

since with such material a substantially monolithic lining could be produced which did not posses's'the open voids and interstices of the old fire-brick construction. Difiiculty, however, has been experienced in the pro vision of such a lining with an efficient and expe ditious method of installation. 7

Perhaps the most common method of providing a suitableplastic monolithic lining included'the laying" of courses of blocks or chunks of the plastic material within the combustion chamber, and the hand-hammering with a suitable mallet or'rammer of each course to' thereby unitethe chunks of one course with'each other and each succeeding course with the preceding one, so that substantially a one-piece'lining would result.- Due to the obviously objectionable process of handhammering, power ramming was adopted with the utilization, of a hydraulic or air rammerand with the resulting more economical and expeditious installation. Of course, in the latter of these installations, namely, withthe use of the power rammer, and quite frequently in the hand-ramming method, an endeavor was made to compensate or allow for the expansion of the lining. To this end, light wooden boards or strips of asbestos were inserted in the lining, especially at the corners, the idea being that the wooden boards would burn out and leave an expansion gap, while with asbestos the natural compressibility thereof would allow for expansion.- However; it was soon learned that the wooden boards would not burn out until the lining had completely vitrified the proper expansion. 5 It was also learned that the hand rammed linings were more satisfactory than the power rammed linings. Quite frequently hand rammed linings remained in use for a relatively great length of time, while the power rammed linings in, nearlyv every instance hadto be reinstalled.- F5 This was due to the fact that with hand ramming, while a seemingly monolithic lining was produced, in reality the lining varied in a most. irregular fashion in degrees of density, so that upon the application of high temperatures, the expansion 10' of the denser portions in the lining would be taken up by those of less density. q r 4 On the other hand, power ramming resulted in a monolithic lining which was nearlyhomogeneous and consequentlyjexpanded as an entirety where-.- upon spalling, cracking and the like occurred with far greater frequency than with a hand rammed lining. It should also be borne in mind that with the hand rammed lining, there was no definite Way of determining just'which lining would'last and which lining would not, these linings; being in addition subjectto shrinkage cracks andsmall ruptures. 1 1, The present invention has been designed to overcome the above noted as well as other. defects and objections in the provision of a hot chamber lining installed in such amanner that the lining may freely contract and expand while inuse with a negligible danger of spalling, cracking, bulging, or similar injuries occurring. I 5 It is also-an object of this invention to-provide a new methodof installing or preparingiforuse a plastic monolithic furnace lining,'the method. permitting the use of a power rammer with. no injurious results after vitrification.

Another object of this invention is the provision of amethod of installing or preparing for useza monolithic lining for hot chambers, which method eliminates the use of any othermaterial than that forming the lining and leaves the lining before and after vitrification free to expand and contract in accordance with temperature variations.

It is another object of this invention to provide a method of installing a true monolithic lining for hot chambers, wherein there a are no separation gaps in the lining even at bridge walls or in places of like character, and the lining'being free to expand and contract in accordance with temper ature variations. under a very high temperature andthezdamage,

'Stillanother object of this invention is the provision of a furnace or other hot chamber lining which eliminates shrinkagecracks by concentrating the shrinkage at joints, eliminates spalling by givingthe material room to expand, and greatly rlengthens the life of thelining by eliminating and showing a further step embodying this invention have been' above pointed out, others will become apparent from the following disclosures.

The invention includes these and other features of construction and a methodof installation or preparation for use hereinafter described, and shown in a preferred manner and form in the drawings, which are deemed desirable for the .purpose of more clearly setting forth the invention, as more particularly indicated'by the claims.

On the drawings: I Figure 1 is a vertical sectional view through-a; furnace lined with plastic material in accordance with the principles of the present invention, the

, section being taken looking towardthe furnace door. 7

Figure 2 is a transverse vertical sectional view through the structure shown in Figure 1. I

Figure 3 is a fragmentary plan sectional view taken substantially as indicated by the line III-III of Figure 2, and illustrating an early step in the installationof the-lining.

Figure 4 is a'view similar to Figure 3 and illustrating a further step in theinstallation of the lining. a r r Figure 5 is a view similar to Figures 3 and 4, in the installation and thepreparation for use of the lining.- -Figure 6 is an enlargedfragmentary sectional view illustrating the manner in which the furnace lining is anchored-to the wall.

As shown on the drawings: In'the drawings selected for the purpose of rendering the presentinvention more clear, there is shown a furnace which includes the customary brick wall'lo, grate 11, and ash pit 12 therebeneath, and boiler 13. V I

The interior of the furnaceisline'd with a plastic monolithic lining 14 of any material suitable-for the purpose, and immediately to the rear of the ash pit '12 a bridge wall 15 ofthe same lining material is provided a'mannei' to be later described herein and whereby the bridge wall may, if so desired, be rendered a substantially integral part ofthe rest of thelining, there being no need of a severance of the bridge wall fromthe lining onthe side walls. V

As seen moreclearly in Figures 2 and'5, the lining is provided at spaced intervals with grooves or joints 16 extending inwardly substantially normally to the lining between the corners, and obliquely at the cornersf These grooves which, it will benoted, preferably, although not necessarily, do not extend entirely through the lining but to a depth in excess of one-half the thickness of the lining, permitthe lining to expand and contract in accordance with temperature variations freely and with practically no danger of resulting spalling, cracking, bulging, rupturingor similar'injuries- Infact, in some instances, these grooves or joints will be substantially closed whenthe furnace is in operation, and open up or-spread when thefurnace is cool. Consequently, the groovesare kept clean throughout the life-of the lining and are not subject to dirt accumulation as is an asbestos or similar filler.

vitrification as well as subsequently that the wall is not dependent upon thereto, so

chors '17, or any other suitable form of anchoring device, are engaged in the wall 10 of the furnace and securely locked position. Each of the anchors carries a relatively broad head 18 there-.

on around: which, the plastic material is rammed in a manner to completely cover the head of the anchor. The plastic material, which is preferably of the consistency of a reasonably stiff putty,"is laid in courses in'blocks or chunks 19 (Figure 3) and repeated. application of power rammers e'ffectively unite the respective blocks and subse quently the respective courses into a homogeneous monolithic mass or one-piecealining 14. As

seen in Figure the ewall 15 forms-an iin'l 14 on the mainxwall'lo',

tegral part of the lining any severe heat treatments before it is capable of functioning be exemplified. At the outset, at suitable intervals, expansion bolt an- Furthermore, the lining may freely expand and contract during as do all other peculiar formations that'mayme required. After the entire liningiis rendered sub. 7 stantially homogeneous in consistency, and while so I still plastic, a suitable power driven chisel is urn lized forthe purpose of cuttingthe grooves'ifi which, as pointed out 'hereinabove, extend inward-1 ly a distance preferably in excess. of one 'halfzthe' i thickness of the lining, e the lining. The grooves or joints are placed at intervals found most suitable, and when, deemed or even. entirely throughnecessary a transversely extending groove orjoint may be employed, asseen inthe central part0! Figure 2.. After the cutting of the grooves, the

lining may be either left} open for aperiodof time to an initial air drying process, or be subjected to a relative y moderate heat treatment for a lesser period of time. In, either instance, the-,liningis subsequently vitrified by using the furnace in, the

customa y manne he. first h atin of,,thejfur hate. to its, relatively-high temperatureresultingin an effective vitrification of the lining. 2

. g It will be noted that. a lininginstalled-and pared for use by the above method, will be, much more compact than theold hand rammed lining, b ina' ar in 'mQS E S aHCQ o ses v: eral more pounds of material per. cubic fQQFOf ni t an is d wi h hand ammin -1,6011% quently, a different and more diijicult pr oblem relative to expansion andcentraction of the s. pr ed, for h nine e and and-c n ct in homogeneous units of substantiallyguniform compactness, and not in an irregular manner-as where the lining varies considerably in density as the result of hand ramming. As pointed out hereinabove, this problem cannot be solved by defining wall sections with strips of some combustible. or

compressiblefiller, nor by any of the other methods heretofore used;- but itis to be clearly noted that, both during and after: vitrification. of the linin the grooves or-joints 16 provide adequate allowance for the expansion of the lining in relacracks are eliminated due to the fact that'the shrinkage is concentrated at the joints. The

.tively large homogeneous units, and shrinkage mass being rendered homogeneousgby power rant.- ming, small ruptures and breakages of aninjuri 1 ous character, either visible at the surface, or in r the interior of thelmaterial are non-.occurrent.

From the foregoing, it is apparent that. I have provided a plastic monolithic furnace lining installable by a new and novel method which permits the use of power ramming means or other expeditious equivalents, lessens the labor and cost of installation and preparation for use, effectively prevents spalling, bulging, cracking, ruptures and similar injuries, eliminates the use of foreignmaterial in the establishment of joints, and adequately allows for expansion and contraction. It will furthermore be noted that repairs, replacements, alterations, and individual or peculiarly shaped structures may be made more expeditiously and economically in accordance with the principles of the present invention than with methods and means known heretofore.

I am aware that many changes may be made and various details of the method varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon, otherwise than is necessitated by the prior art.

I claim as my invention:

1. The method of preparing a furnace lining for use, consisting of applying plastic material and highly compacting the same until substantially a monolithic lining is formed, then cutting continuous grooves in said lining substantially normal thereto to a depth in excess of half the thickness of said lining at spaced intervals between corners, cutting like grooves obliquely at corners, leaving said grooves empty, and hardening said lining.

2. A monolithic plastic furnace lining for extending around the lined parts of a furnace and.

having spaced empty continuous grooves therein arranged to divide the lining into unitary expansion sections, said grooves being of such a size and depth to permit an initial shrinkage of said lining when first drying out and then a relative over expansion when the lining is initially hardened by the application of heat, and. said sections subsequently expanding and contracting with temperature changes during the use of the furnace, the grooves opening and closing proportionally.

3. A method of installing a monolithic furnace lining of plastic refractory material which consists in ramming the material into place and thereby compressing it to a substantially uniform density and forming in the fire receiving face thereof a plurality of elongated narrow grooves of a depth slightly less than the thickness of the lining and keeping said grooves open and exposed to the furnace atmosphere while hardening and vitrifying the lining.

4. A method of installing a monolithic furnace lining of plastic refractory material which consists in ramming the material into place and thereby compressing it to a substantially uniform density and cutting out and removing narrow sections of the material to form in the fire receiving face thereof a plurality of elongated narrow grooves of a depth slightly less than the thickness of the lining, and keeping said grooves open'and exposed to the furnace atmosphere while hardening and vitrifying the lining.

GEORGE F. DOYLE.

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