US1816322A - Method of retaining and sealing furnace structure - Google Patents

Description

July 28, 1931. R. 1.. FRINK 1,816,322

METHOD OF RE'lAIIIINGr AND SEALING FURNACE STRUCTURES Filed Dec. 16 192 Patented Jul 28, ,1931

' RoBERrL. ERIN or LANCASTER, oHIo METHOD or RETAINI' GT AND SEALING FURNACE s'rnuo'runr Application filed DecemberIG, 19 26. Serial No." 155,329.

1 This invention relates to methodof retaining and sealing linings resistant to erosion Where thereis more or less' chemical action and heat, and in its more specificaspects, it

f5, has reference to linings for furnaces treating materials in industrial usages such as involve severe action along heated zones ofcontact. For example,in glass melting tanks, thelinings are subjected tovery drastic conditions.

I Likewise-with copper refining furnaces, also boiler furnaces,'particularly those fired by powdered coal, 6130;, where the erosion'is very severe. .Very durabIe or highly refractory materials are' knownthat offer advantages but their high cost has rendered their use prohibitive in the dimensions required in the prevalent self-supporting types of construction. Moreover,;with such refractory materials'as mullite, etc., the heat-"conductivity is such that these materials if used alone would permit excessive'iheat losses through the walls. In accordance with my present invention, it now becomes possible to secure a highly-resistant surface together with the other-qualities, desirable at the same time, and coincidentally produce a-sealing ofthe 1 joints.

" Tothe accomplishment :of the foregoing and related ends, the invention, then, consists in'ithe features hereinafter fully described and particularly pointed out in the claims, the following. description and the annexed drawings illustrating buta few of the variousforms in which the principle of the' inven-. tion may be used.

*In said annexed drawings Fig. 1' is a fragmentary isometric and sec tionalview. showing aportion of a wall and floor construction embodying the present invention; Fig. 2 is'a similar view of a modifi-' cation; and Fig. '3 is a sectional view illustrating the invention as applied to effect a seal betweenjointsqv -The reference numerals 1 and 2inthe drawings yjdesignate facing slabs, or "blocks of highly-resistant ordurable material. This may be selectedas desirablefor a' particue lar usage in vi'ew. For example, with a glass melting furnace, or: tank. mulliteor sillima nite, maybe employed. Back of the facing naces, I prefer to make up amixture of disslabs aresupport or backing blocks 3, 4, of

inferior material and which maybe of'less density. Blocks 5v and 6 of ordinaryfireclay material form the base, and ablock 7 of sim ilar material may-be arrangedabove. By y. providing the blocks (Sand 7 with under-cuts or rebates or the like, asfor instance at 8, and correspondingly shaping the coacting edges of thelfacings land 2, the latter'will be restrained against displacement 'forso Wardly and at thesame time they are held against the backing 3 and 4. 'As a further safeguard, there may be provided a sort of dovetailing of more orless pronounced form,

as at 10in themating edges of the facing 66' slabs so as to' assist in retainingthese in relation; In assembling the construction as shown in-Fig-l. the'fioor or base blocks 5,, 6, are laidin position and then the backing blocks 3,4. ,Thefacingslabs land Qare 7e nowiset in position andthen the top block 7 which with its overhanging edge serves to maintain thefacing in position;

In some instances, I not-only secure the respective'members together butv also efi'ect a seal by providing in the mating surfaces grooves which may be of circular orsquare cross section for instance asat 11 or 12 or of double under-cut cross section as at 2. Such grooves, with the respective blocks. assembled, present then longitudinal 'channelsinvolvingboth mating surfaces, and these channels arethen filled'with a locking key which may bezof square section asat.13,whichis preferable for certain. kinds of seals. Preferably and -.most conveniently, such .a key may be provided by. forcing in a plastic mass which when properly set will afford a suitable mechanical tie. As to the characteristics of such mass, it is desirable ofcourse that it be capable offresisting temperatures to which thewall'structure may be subjected in use, and accordingly the particular ma; terial mayfva'ry as 'determined'by the usage iniview. It is desirable alsoin most cases at '05 least that the key, masshavea coefficient of expansion and contraction practicably re late'dto' that of the blockstiedtogether or seal to be made. :In the case ofv glass furintegrated sillinianite with a binder comprising silica, boric acid, thorium or zireoninin oxide, magnesium oxide and magnesium chloride, the respective quantities of each of the constituents being determined by the use to which it is to be applied, i. e., the relative co-efficient of expansion between the parts to be joined, or the conditions under which a seal is to be made and maintained; in each case, the quantity of magnesium on ide and magnesium chloride to be used will depend upon the amount of cementing action desired. Just enough water is added to dampen the mass and make itadequately flowable to be inserted into the channels, and these having been filled from a convenient oint of access, usually at the end, the mass is allowed to dry out, and is ultimately set to final condition by heat, the temperature heingsuch that incipient fusion or softening to an: extent of allowing the adherence of the particles occurs. VVherea key effect only is desired,themass should be brought toa temperature above 1400 C. unless the posi tion in: which the key is 'zised and the temperature towhich it is subjected is a mere nominal'temperature of from 1200 to 1300 Q, Where it would then be feasible to use a mix tnrehaving arlower melting point, as by the addition of alkali borates or carbonates. It is. advisable that the softening temperature be maintained somewhat longer in order to aillowof chemical and physical adjustments in the mass. It will then be found that the plastic material has become a rigid key whose fusion pointis so high that it mechanically holds in the conditions of usage to which the furnace is thereafter subjected. The firing temperature for the setting of the plastic keymixture will of course vary with the parti-cular material employed, but where such material is substantially of a sillimanite and boron silicate type instanced above, a temperature of 1400 to 1500 C. or more will be desirable.

As shownin Fig. 3, Inembersmay be joined with w seal to form hollow bodies or conduits, 815 for a recuperator system.

It has been found that to construct a recu perator tile by any of the present known methods, thatproduce the same in an integral piece, is unsatisfactory because ofthe variation of temperatures that occur, and the" continued subjection of high tempera tures over long periods of time causes such tiles to crack, especially where the partition member 9 is subjected to a higher temperature than the walls" 9'. An unequal or differential expansion occurs between the walls 9 and'sec-tion 9 causing cracking and disinte "grationf It will be appreciated that, when these tiles are used in recuperators eitherthe exterior is subjected. to a temperarture of atmowher'ie air while the. gases flowing through the interior-may have a tempbrature of 1200 or 1300 C.., or the conditions may be vice versa.

To also meet these conditions and avoid such cracking of the tiles or conduits, with consequent leakage of the ingoing air and outgoing hot gases, thus necessitating the closing down of the furnace, my invention is found entirely satisfactory when properly executed, and while the principle and the elements embodied are substantially the same whether used as a seal or a key, when used as a seal I preferably employ the following procedure:

Grooves are ground or formed into the mating surfaces between members 9 and 9'. The parts are-brought into the required alignment and a mixture of'sillimanite or mul lite wit-hboric acid, thoria orzirconium oxide is compounded withmagnesium oxide and chloride, the mass is moistened and isthen injected bymeans of a pressure device or gun into'the recesses as shown in Fig. 3 un-: til'filled, as at 13. This is preferably done during the building of therecuperator or other furnace parts. lVhen heat is applied and the masses at 13 are sinteredror. fused, gases are evolved and some shrinkage takes place, and to govern the'quantity of shrinkage required to compensate for differential movements between members 9 and 9, I may add varying quantities of alkali, carbonates, and raw fireclay which has been deflocculated or contains the larger possible quantity of flocculant or colloidal. material.

Should itbe desired thatthe construction be more or less monolithic it is thenadvisa'ble to add increased quantities of alkali and carbonates to" thereby lower the fusion point, creating a greater quantity of glassy substance and obtain a relatively, larger surface of plastic material in contact with the" mating surfaces.

It will thus be seen that with. a construction on the general lines described, advantage may be taken .of the superior resistant properties of costly and difiicultly workable facing slabs in relatively thin section, andlsuch lining may be'successfully backed up or used conjunc tion with cheaper and in some instances bet.- ter insulating substances, the assemblage being adequately held together in use by the overhanging engagement or by the plastically-introdu'ced key or both or' seal to close pas sages that might allow circulation of gases, as inrrecu'perators, or fluids, as between the notch block and floater, or the bonds between spouts and base walls, etc. as circumstances may make advisable, the wedge surfaces or retreating wedge surfaces of the respective members making an effective and durable in terlock. in engagement whether initially rigid orplastic. Theextent to which-the facing will be applied will of course depend upon the particular usage in hand. In some cases, the entire side walls and the floor' being covered, and in other cases only the side wall will require the facing. In other cases yet, all of the side wall will not require facing but only the zone at the upper part where the material being heated has its general range of exposed surface as a fluid level line con tacting the Wall. v

Moreover, irrespective of the particular character of the membersto be joined, whether in a solid wall or a hollow built-up structure, the wedging or locking member provides holding or sealing functions or both, and by the terms wedging member or locking member hereinafter, I contemplate either or the invention may be employed, change being I tinctly claim as my invention made in the details set forth, provided the means and steps stated in the following claims or the equivalent of such be employed.

I therefore particularly point out and dis- 1. In construction of the character described, the combination of heat-resistant members having apposed surfaces provided with recesses, and a locking member fused in such recesses the locking member being glass like in character.

2. In construction of the character described, the combination of heat-resistant members having apposed surfaces provided with recesses, and alocking member of glasslike composition fused in such recesses.

3. In construction of the character described, the combination of a facing block resistant against action of material to be treated in contact therewith, a backing of less resistant material, and heat resistant locking members for holding sald facing against the backing.

4. In consiruction of the character de- K scribed, the combination of. a facing block substantially resistant against action of material to be treated in contact therewith, a backing of less resistant material, and heat resistant locking members comprising upper and lower blocks having non-planar surfaces for holding said facing against the backing.

5. In construction of the character described, the combination of a refractory facing block highly resistant against action of materials to be treated in contact therewith, a backing of less resistant material, andfusible locking members engaging the facing and backing.

the character described, which comprises apposing heat-resistant members having mating channels, forcing a plastic locking material into such channels, and fusing at least a portion of the locking material.

10. A-method of making a construction of the character described, which comprises apposing a facing and a backing having mat-- ing channels, forcing a plastic material into such channels, and suIo ecting the material to heat to set the same mto required rigid form.

11. A method of making a construction of.

the character described, which comprises setting up a backing apposing a refractory facing thereagainst, said backing and facing having mating channels'so formed as to coact with material therein to key the backing and the facing together, forcing into the channels a plastic material capable of setting when heated, and heatin 1.2. In a wall madeup of a plurality of apposed members, the combination with recesses in adjacent faces of said members, of a keying and sealing member disposed in said recesses and fused to said members.

Signed by me this 14th day of December,

ROBERT L. FRINK.

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