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Aug. 9, 1938. c. E. HAwKE 2,126,325 'RETORT AND RETORT SETTING Filed Oct. 2l, 1936 3 Sheets-Sheet 1 ¿7. 1. fr l/ l l w“EE.WHmm C | A R C. N ATTORNEY. KE Aug. 9, 1938. 2,126,325 c. E. HAWKE RETORT AND RETORT SETTING Filed Oct. 21, 1936 3 sheets-Sheet 2 25 NLM ‘y INVENTOR. CLARENCE E. HAM/_KE BY M ATTORNEY. Aug. 9, 1938. c. r-:. HAWKE V2,126,325 RETORT AND RETORT SETTING Filed oct. 21, 193e 3 Sheets-Sheet .'5l „n.143 INVENTOR. CLARENCE E, HAWKE BY ATTORNEY. 2.126,325 Patented Aug. 9, `1.938 UNITED STATES . PATENT oFFlcEa aizsszs ' ’ amour AND uproar sn'rrmc Clarence E.l Hawke, Metuchen, N. J., assigner, by mesne assignments, to The Carborundum Co pany, Niagara Falls, N. Y., a corporation of Del- _ applicati@ october 21, issn, ser-n1 No. 106,867 s claims. (ci. 263-37) A This application relates to improvements in retorts and retort settings. More particularly the silicon carbide, which has a high thermal con ductivity (for a non-metallic refractory) and' application is concerned with vertical retorts _which retains great strength to compressive loads composed of non-metallic refractories, and used at the temperatures to which retorts are ordi 5 for metallurgical purposes or for the calcination narily subjected. This characteristic permits of minerals. The present applicationis a- con the use of this material in thin sections. Even tinuation in part of my copending application this refractory is liable, however, to the develop Serial No. 47,381, filed October 30, 1935. (U. S. .ment of hair-line cracks during prolonged' Patent 2,067.085.) ' periods of operation in which strains are pro 10 In such industrial applications as have been . indicated above, gases or vapors _are often given oil in 'great abundance as in they case of the re fining of zinc or in the calcining of limestone. duced by non-uniform heating or by rapid c'ha'ngesin temperature or by changes in local ' pressure. 15 reasonably gas or vapor tight structure in metal sary to use non-metallic retorts. ' \ Non-metallic refractories are extensively yused 20 where resistance tovchange of shape at high temperatures and chemical inertness at high temperatures are required. It is not possible to construct a retort of non-metallic refractory ma terials that will be absolutely gas or vapor tight. 25 Retorts can be built up of lnon-metallic re Such causes are likely to produce changes ’in [volume which are not uniform throughout 'a given >refractory element. `The There are many diiiiculties Vin ~ maintaining a lurgical and other retorts during prolonged periods of operation,.especiallywhere it is neces 10 strains so produced must be relieved, and are re lieved when the refractory _element cracks or fractures. These cracks may not be visible when ' they ñr'st occur on account of the minute4 thick ness of the openingproduced. They will open up . to a greater extent during prolonged periods of heating'unless some force is applied tov prevent the opening. ' ' - _ In the case of a vertical retort therefore: the ilne cracks which occur in a horizontal direction are not likely to open up to _any serious extent fractory elements consisting of superimposed 25.. hollow one-piece sections. The walls of a retort », » because of the superincumbent weight which can also belbuilt up by using»\ combinations of refractory shapes with both horizontal and vverti 'cal joints `which can `be lapped or which can have tongue and groove connections. The sections or ` elements oi' a retort can also be cemented to gether.' Such structures can be made ~reasonably tight and will show little or no gas or vapor leak .' age, provided pressures are balanced within an inch or two of hydrostatic pressure. Such re torts, however, will not stand prolonged periods of operation without developing leaks either’ throu'gh‘the opening of the vertical joints, or be 40 cause "of the development and opening of cracks in_ the body of the refractories employed. . _x tends to close the openings. The case is quite diil’erent with vertical cracks.“ This invention is concerned principally with lthe development of practical means for preventing vertical _cracks from opening up in retorts built of non-metallic refractories. . - " Forpurpcses o'f illustration my invention is " `f_lescribed with reference to vertical retorts hav ing a rectangular cross-section. The type- of re 35 tort has long sides _(as illustrated4 in the ac- f companying drawings) and-narrow ends, the4 heat being transmitted from sources of heat situ- ~ `ated outside of the opposite side walls. In the accompanying drawings: ' _ , 40 I have -discovered that, in retorts of the type Figure l shows a horizontal section of a retort just "describe?, little or no'trouble _is caused by mounted in a furnace, the section being taken on the opening oi' horizontal joints orby the de-` the line I-I of Fig. v2; _ I i 45 velopment or opening of cracks extending in a» 'Figure 2 is a fragmentary sectional elevation 45 horizontal direction. This is due to the fact> that taken on4 the ‘line II-II of Figure l; the load imposed upon the refractory elements Figure 3 isl a fragmentary horizontal section . by the upper portion of'a retort (including the taken on the line III-»HI of Figure 4 and illus portion of the retort which extends beyond _and ftrating a modification‘of the means used for ap above the heating chamber)` prevents the open plying pressure to the end walls; ‘ ' ~ 50 ing of 'horizontal joints or cracks and the de Figure 4 _ is a fragmentary sectional elevation velopment and opening of cracks extending in a taken on the line IV--IV of Figure 3; _ horizontal direction. o l , Among the refractories which are most useful 55 for high temperature work may be mentioned Figure 5 is a fragmentary horizontal section il lust'rating means for facilitating movement of a i _ompression _member in a vertical Ydirection 55 . 2,126,325 2 where such ïmovement is desirable to reduce stresses resulting from`temperature changes; sure in a- horizontal direction to either one or ~ both ofthe narrow ends of the retort by com Figure .6 is a, fragmentary horizontal section pression means attachedl to the outside struc of a retort and adjacent setting, the end of the ture of the retort setting. For example, in Fig 1 the movable blocks 1 and Il are urged to -retort’shown being. oppositely disposed to that ure ward the respective ends of the retort by means shown »in Figure 5; Figures ,7l and 8 are fragmentary elevations of the springs 9 and I0. _The amount of com may be adjusted, for ex ~partly in section illustrating means for-applying pression in the springs the member I2 which is by rotation of horizontal. forces 'to pairs of compression blocks f ample threaded in the cap I3. As indicated in Figure 2 which are in contact with end walls of the re spective retorts, the form of the joints between individual pressure-applying means may be used adjacent tiles of the retorts being different in the on a number of superimposed tiles in the end walls.` two views; Figure 9 is a horizontal section of a retort and> f is of part Yof’ the setting and shows side walls of the retort which can expand or contract horizontally independently of the end wall shown at the left; and , ` f Figure 10 is a view similar to Figure 9 but showing weighted crank means for applying hori zontal forces. to the side walls instead `of spring means.- x ?_ Referring to the drawings in detail there is shown'in Figure 1 an elongated retort 2 whose sides 2 are made as long as practicable. Heat is transmitted to the material inside the retort through these long sides from combustion cham bers 4. The distance between the side walls of » the retort mayvary from 2 inches to 18 inches depending uponthe process involved. The eñec tive heating of the material within the retort will not be much affected by the length of the walls 3, `that is by the horizontal dimensions of the heat ing surfaces exposed to the combustion chambers. On >the other `hand if the distance inside the re tort between the side walls is too great, the ma terials near the wall of the _retort will be over heated before the materials in the center of the retort reach the desired temperature. " The op 40 timum distance Ibetween the side walls will de f In the modification shown in Figures 3 and 4 the end walls of the retort are pressed with the aid of blocks 1', which in turn are pressed by means of weightedlevers such as that indicated at I4. Pneumatic or hydraulic pressure devices mayalso be utilized, the hydraulic pressure being cushioned by means of a spring or by means of compressed air, as illustrated diagrammatically in my U. S. Patent No. 2,067,085. f Horizontal forces should be applied to a suill cient number of the end wall. elements to prevent any vertical cracks or joints from opening up in 25 the side walls as the result of internal pressures `produced by the load in the retortor by the de velopment of gases or produced as the result of the expansion and contraction of refractories when heated and cooled through extensive ranges 30 ofv temperature. The means Vused for applying thesehorizontal'iorces must be flexible enough to absorb the normal expansion of the refractories caused by the application otheat thereto and also flexible enough to maintain the horizontal 35 pressure' in the`event of any contraction due t0 cooling.'l In the case of the modification shown in Figures 3 and 4 the horizontal forces are ap plied through rollers Iä which are rotatably mounted in a lower extension ofthe lever Il. 40 pend on the thermal conductivity of the materials `The end walls are therefore `not prevented from vertical expansion or contraction by their con under treatment. y tact with the pressure-applying means. Where It has» been found that little or no trouble no such rollers `are shown (as in Figures 1 and 2) occurs through cracking of the refractories in the the applicationof horizontal forces can be omitted end walls 5 since these walls are not exposed to during the heating up period until the retort is 45 the combustion gases and are also’ of relatively _ small horizontal dimensions, so that vit is anot usually necessary to use vertical joints in these end walls 5. The _difilculties described above have been experienced in the side walls which are usually several feet in length and which therefore have to be built up from tiles with vertical as -brought to operating temperature. The horizon tal forces are then applied by tightening up on the threadedy bolts I2 until the desired compres sive >force is obtained. With this arrangement, 50 the spring pressure should be released before the retort is cooled. In the modification >shown in Figure 5 pro- Y well as horizontal joints. While in some ofY the . vision is made for the movement of the com views the retorts have been indicated without vertical joints, vertical -cracks are `likely to form pression member‘l’ in a vertical direction, where, 55 duringthe operation of the retorts. One of the for example, relief is needed from strains due to objects of the present invention is to prevent such changes in temperature. In this case the rollers I8 are carried by brackets I8 which are in. turn cracks'from opening up. ' For efilclent operation the side walls of the securely attached to the supporting members 2| retort have to be-built of a material having a of the retort setting. The plate 22 (to which the high thermal conductivity while the walls 6 of compression member 1' is attached) is thus per the combustion chamber are built of a poorly mitted to move in a vertical direction during ex conducting refractory such as hre-clay. As these` pansion orcontraction of the retort relatively to supporting members 2l. _ i’ two types of materials have `in general different `theReferring to Figure 6, one end of a retort may rates of expansion, it is essential that the retort should not bevv rigidly tied in with the structure abut against rollers 23 which are supported on of vthe setting, -for if this is done the entire the retort setting while' the opposite end of the retort structure may be subjected to such strains retort is pressed by the resilient means shown in Figure 5, which means is vertically movable with as’ will cause destructive cracking of the refrac Yrespect to the adjacent setting asf‘ explained 70 tories and the opening nup even of horizontal è f_ joints. It is impractical therefore to hold the above. In the modification shown in Figure ’I means` - retort in compression from the sides by» rigidly tying the retort structure in with the structure are shown for applying a horizontal force to two compression blocks located adjacent-an end wall of the‘setting. ‘ ' of a retort by means of a single force mecha-- 75 .In the practice of my invention I apply pres 75. 2,126,325 nism. In this case a weighted lever mechanism (of the bell-crank type) is indicated in the draw ings, but other means such as springs or hydro pneumatic or pneumatic means or hydraulic means (cushioned by springs) may be used for applying the horizontal forces, as illustrated >diagrammatically in my U. S. Patent 2,067,085. The modification shown in Figure 8 is similar automatically controlled means disposed between the setting and a terminal portion of each side wall for applying independently to each side wall horizontal pressure tending to close verti cally disposed joints and cracks. 4. A retort having side walls for heat trans mission from exterior heating sources and end walls contacting with the retort setting, means to that shown in Figure 'i except that the form disposed between the setting and a terminal por- ' of joint between the tiles that compose the end walls and side walls of the retort is diilerent. In the modiñcation shown in Figure 9 horizon tion of each side wall for applying independently 10 to each side wall horizontal `pressure tending to close up vertically disposed joints and cracks, and cavities adjacent to terminal portions of the side walls containing finely divided material for sealing under the action of gravity the side walls with respect to the end walls and the retort tal pressures are exerted on the side walls through terminal blocks 34. The joints in the end wall that run parallel to the length of the retort are sealed by means of loose packing in the chambers 35. Gravity forces this packing against the members 34 and causes a seal be tween the members 34 an-d the intermediate 20 portion of the end wall and also between the members 34 and the adjacent retort setting. As has been indicated above, the walls of the retorts are made of a non-metallic refractory having a low coeñicient of thermal expansion and 25 a high degree of mechanical strength at high temperatures, such as bonded silicon carbide or recrystallized silicon carbide. Other refractories havinga thermal conductivity greater than 0.006' calorie/cm3/sec./°C.,may be used if they possess V30 the required mechanical strength, resistance to spalling and chemical inertness. The walls, of the retort setting can be made of ñre-clay backed with steel beams as indicated in Figure 1 of the drawings. 35 3 setting. 5. A furnace for the heat treatment of mate rials comprising an elongated retort of rectangu lar cross section having extended side walls for 20 heat transmission from combustion chambers located on each side ofthe retort and having narrow end walls one of which ñts loosely be tween said elongated side walls, an outer furnace wall surrounding the retort and the combustion chambers, said outer furnace wall having two movable sections of superposed blocks in contact with the respective loosely ñtted ends of the side walls, and yieldable means for pressing said side walls of the retort in a horizontal direction. 30 » 6. A furnace for the heat treatment of mate rials comprising an elongated retort of rectangu» lar cross section having 'extended side walls for heat transmission from combustion chambers While I have described several methods by which the invention may be applied to vertical located on 'each side of the retort and having 35 narrow end walls one at least of which fits loosely retorts, the principle underlying these methods l between said elongated side walls, an outer fur» is applicable to a still wider range of retort types nace wall surrounding the retort and the com and arrangements with their associated settings. ' bustion chambers, said outer furnace Wall hav 40 'I'he drawings are` intended to illustrate the ing two movable sections of superposed blocks in 40 practicability of the application of the invention in a Variety of forms. I claim: g 1. A furnace for the heat treatment of mate 45 rials comprising an elongated retort of rectangu lar horizontal cross section and having extended side walls forfheat transmission from combustion chambers located on each side of the retort and having narrow end'walls joining said side walls, 50 said end walls being shielded from the combus tion gases, an outer furnace wall surrounding the retort and the combustion chambers, said outer wall having a movable section of superimposed blocks adjacent one end of the retort, and a plu 55 rality of weighted bell-crank levers for exerting horizontal forces against the adjacent end of the retort and tending to close vertical cracks in the side walls of the retort. - 2. The furnace structure described in'claim 1 60 in which the bell-crank lever compression mech anism transmits pressure through a member mounted for slidable movement in a vertical direction with respect to the outer wall of the furnace. 65 3. A retort having side Walls for heat trans mission from exterior heating sources and end walls contacting with the retort setting, and contact with the respective loosely ñtted ends of the side walls, yieldable means for pressing said movable sections of the outer wall against side walls of the retort in a horizontal direction, and cavities adjacent to terminal portions of the side 45 walls containing loose granular material for seal ing under the action of gravity the side walls with respect to the end walls of the retort and with y respect to the outer furnace wall. 7. A retort having side walls for heat trans mission from exterior heating sources and end walls contacting with the retort setting, and gravity controlled means disposed between the retort setting and a terminal portion of each side wall for continuously applying independently to 55. each side wall horizontal pressure tending ‘to close vertically disposed joints and cracks. 8. Agretort having side walls for heat trans mission from exterior heating sources and end walls contacting with the retort setting, and re silient means disposed between the retort setting and a terminal portion of each side wall for con tinuously applying independently to each side wall horizontal pressure tending to close verti cally disposed joints and cracks. CLARENCE E. HÀWKE.