US2840363A - Furnace structure - Google Patents

Description

June 24, 1958 R. J. PENROSE 2,840,363

FURNACE STRUCTURE Filed Feb. 14,1956 s Sheets-Sheet 1 Re yno/Q" d. Penn as e INVENTOR.

June 24, 1958 R. J. PENROSE FURNACE STRUCTURE Filed Feb. 14, 1956 v 3 Sheets-Sheet 2 Reyna/d d. Pen "0s e INVENTOR June 24, 195 8 F Filed Feb. '14, 1956 R. u. PENROSE 2,840,363

mama: STRUCTURE 3 Sheets-Sheet 3 Reyna/d d. Penroae INVENTOR.

United States Patent Ofiice 2,840,363 Patented June 24, 1958 2,840,363 7 FURNACE STRUCTURE I Reynold J. Penrose, Houston, Tex.

Application February 14, 1956, Serial No. 565,509 3'Claims. Cl. 263-21) The present invention relates to a furnace structure and, more particularly, relates -to furnace structures of the refractory retort, mufile and hearth type.

As heretofore practiced and well known in the art, all refractory or ceramic retort, mufile or hearth type furnaces which introduce a feed of ores, metals or metal objects into a receiving end and pass the feed through a furnace and discharge the heat treated feed beyond the walls of the furnace employ some means of supporting the refractory retort, muflie or hearth in the furnace combustion chamber. These supporting means include heat resistant steels, alloys of metals or iron in the construction of the support. It is well known that such supports within the furnace and in the heat treating zones are subject to warpage by heat expansion and damage caused by the high temperatures of which this type of furnace is required to operate. This causes considerable difliculty due to the resultant misalignment of the retort, mufile or hearth I,

'It is also known in the art of heat treating that steels, alloys of metalor iron have a tendency to become, according to the composition of the metal, what is known as tacky when subjected to temperatures beginning as lows as 900 F. That in the heat treatment of certain materials, for example, micaceous minerals and/or hydrous silicate minerals for the purpose of expanding them, that these minerals adhere to and form glassy and slaglike fusions to the steels, alloys of metals or iron that have been used for the construction of retorts, niuflles or hearths, and therefore, free passage is denied and the furnace becomes inoperative. 7

It is therefor a major object of the present invention to provide a furnace structure in which misalignment of refractory retorts, muflles or hearths caused by the expansion of steels, alloys of metals or iron for supporting the same within the combustion chamber of the furnace is substantially eliminated. p

A still further object of the present invention is the provision of a furnace structure including a retort, muffle or hearthin which macaceous minerals and/ or hydrous silicate minerals may be expanded or other materials heat treated in the range covering 900 to 2,600 F. without becoming tacky and adhering to and forming glassy and slag-like fusions to the passageway therein so that a free passage is maintained at all times.

A furtherobject of the present invention is the provision of a furnace structure including a refractory retort, mufile or hearth which is freely maintained within the heat zone of the furnace structure by means of compressive forceagainst ends of the former and where said means are so constructed and arranged as to be outside the walls of the furnace structure and have no metal part within or connected thereto.

Yet a still further object of the present invention is the provision of a furnace structure havinga novel con struction to prevent the transmission of heat through the projecting ends of the refractory retort, muflle or hearth,

the latter being arranged to pass through the furnace walls and project therebeyond for receiving material to be heat treated at one end and discharging the heat treated material at the other end thereof.

Yet a still further object of the present invention is the provision in a furnace structure of a simple but highly eflicient burner for the combustion chamber thereof for providing luminescent heat from gaseous or oil fuels whereby the heat is evenly distributed over the bottom, sides and top of the material passageway extending therethrough and in which the burner is economically and readily constructed out of conventional material as part of the furnace structure.

It is yet a still further object of the invention to provide a burner which is efiiciently reliable in use and is so constructed and arranged as to conserve heat and eliminate the use of large amounts of air to keep the burner cool at operating temperatures.

Other and further objects, advantages and features will be apparent from the following description of a presently preferred example of the invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings, where like character references desigate like parts throughout the several views and where V Figure 1 is a fragmentary view, in elevation, illustrating means for holding a refractory retort, mufile or hearth in place in the furnace structure,

Figure 2 is a longitudinal elevation, similar to Figure 1, but illustrates in section the means for holding the refractory retort, mufile or hearth in placeand its relation to the furnace structure and burner arrangement,"

Figure 3 is a horizontal, sectional view taken along the line 33 vof Figure 2,

Figure 4 is an end, elevational view taken transversely of the discharge end as indicated by the line 4-4 of Figure 2, a

Figure 5 is a vertical sectional view taken transversely of the furnace arrangement along the line 55 of Figure 2,

Figure 6 .is a horizontal sectional view of a burner block according to the invention taken along the line 6 ,6 of Figure 2,

Figure 7 is a horizontal sectional view of the furnace top taken along the line 77 of Figure 2, and

Figure 8 is a fragmentary, enlarged side view, in full thickness, illustrating space voids between the central and end sections of the conveyor of the furnace structure.

Referring now to the drawings, and particularly to Figure l, a cradle or support arrangement is illustrated for the refractory or ceramic retort, muffle or hearth within the hollow of a furnace. To this end, a suitable metal I-beam 17, or other similar supporting member, is, provided in a generally horizontal position to which is attached-at its upper surface, two web- like metal uprights 14 and 14a. The upright 14 may be welded or otherwise rigidly secured, such as bolting, to the I-beam 17. The upright 14a is attached to the I-beam 17 in any preferred manner to permit longitudinal adjustment along the surface thereof, for example by the bolts 15, which slidably fit in slots, not shown, in the surface thereof so that it may adjustably be bolted into position by the bolts 15 and the thrust screws 16 to provide endwise compression for supporting a retort, muffle or hearth,

.as will presently be described.-

is to support the muflle, retort or hearth, as previously mentioned, and to support it by providing endwise or compressive pressure against the outer ends thereof. Prefa p i 3 erably, the material supporting means 14 and 14a may take the form of steel or metal blocks, generally of L-sh-aped configuration, into which the ends and 12 of the retort, muffie or hearth interfit so that endwise or compressivepressure may be brought to hear thereagainst.

Referring still to Figure 1, the refractory retort, mufile or hearth includes the refractory or ceramic tile 10 which is placed against the material, supporting element 14", as previously described, and the refractory or ceramic tile 12 which is likewise. placed against the material supporting element 14a. The'center section .11 is a separate refractory or ceramic tile'fromthat of the elements 10 and 12 andis supported in position by means of endwise pressure exerted against the elements 10 and 12. Preferably, the interfitting portions 13 and 13, such as a conventional tongue'and groove construction, are provided. on. each end pf thecenter tile 11 and the inner projecting ends of the tiles 10 and 12 to assure support of the center section 11. As best seen in Figure 8, the spacevoids 13a are provided at each end of the interfitting portions 13 and 13' (only one end portion being shown in Figure 8) to provide heat barriers against transmission of heat to the outside of the furnace chamber. Preferably, this is accomplished by utilizing a somewhat granular ceramic tile 10 although it may be accomplished in other ways. a a

It is therefore apparent that by adjusting the bolts and 16 the center section 11 is, supported solely by endwise pressureoccasioned by moving the upright web 14a towardthe .web. 14, and the related structure previously described, and by securing the bolts 15 and thrust screw 16 in adjusted position Also, it seems apparent that the retort, mutfle or hearth issupported in. this position freely of the furnace structure proper but is supported. wholly by. means of the cradle arrangement described. It is noted. that a passageway for the fiowof material to be heat treated is thus provided through thecombustion chamber and is supported at its ends free of the combustion chamber. Sincdthe passageway may be of the retort, muffie or hearth type, for convenience of reference, these and others are all generally designated as a passageway for the material to beheat treated.

Vibrating motion is imparted to the cradle and thereby to the passageway composed of the elements 10, 11 and 12 by means of any conventional vibrating unit, for example t-heunit illustrated diagrammatically in Figures 1 and 2 and designated bythe reference numeral 20. The

intensity of the vibration is controlled by the means di'agrammatically illustrated at 22.

vided with the vibrating unit and the latter is linked to the cradle by any suitablelinking means, such as illustrated in Figures 1 and 2. No detailed description is deemed necessary of the vibrating elements as these are conventional, may be purchased on the market, and as such, form as partof the invention. Obviously, a wide variety of vibrating means may be used.

Thecradlc 17 is further supported at the end remote from thevibrating unit 20 by means of the transverse support beam 18 which is supported by the pair of spring legs 19, as best seen in Figure 4. Thus, due tothe spring arrangement, vibrating motion is imparted to the cradle and hence to the retort, muffle or hearth. It is noted that the cradle unit and; passageway are separate from the furnace proper and that no vibrating motion is imparted to the furnace proper.

i Turning now to Figure 2, the furnace proper is illustrated in position with respect to the cradle and passageway for the material to be heat treated. The furnace proper'is illustrated in longitudinal section and includes the furnace bottom 23 which has the fuel entrance manifold port .24 for furnishing premix fuel to the distributing manifolds 25 and thence to theslots 26, ,asebest seen in Figure 6, into the furnace chamber. directly under the The spring 21 is pro center portion 11 of the passageway for the material to be heat treated. For the purpose of disclosure and ease of illustration, the furnace top 28, ends 34, 34', 36 and 36', and walls 27, see Figures 4 and 5, are shown as large cast blocks. In actual practice, these elements may be of any conventional furnace construction. The bottom front block 34 is constructed of suflicient height to bring its top surface sutficiently close to the bottom of the tile 10 so as to provide a minimum space for the escape of combustion products and to provide a minimum clearance for the vibratory action of the tile 10. The furnace chamber side of the. block 34 preferably should be directly under and vertical to the interfitting portions 13 of the tile 10 and the center tile .11. Similarly, the bottom back block 34 should be similarly arranged, as illustrated.

The top front block 36 fills the space between the top of the sidewalls of the tile 10 and the bottom of the furnace roof that is junctured with the walls. The furnace chamber side of the block 36 preferably is directly above and vertical to the interfitting arrangement 13 of the tile 10 and the center tile 11. The top back block 36 is similarly arranged with respect to the tile 12.

With the blocks 34, 34 and 36, 36' being so arranged, the space on each side of the tile 10 and the tile 12 is filled by the blocks 35 and 35 as illustrated in Figures 4 and 5. The position and arrangement of the side blocks 27 are illustrated in Figures 3, 4 and 5.

The roof of the furnace is diagrammatically illustrated as the block 28 in which vent holes 29 are cast or drilled to provide escape for the heat scavenged products of combustion from the furnace, all as best seen in Figures 2 and 7..

The furnace proper is supported by the diagrammatically illustrated blocks 38, ordinarly brickwork, and thus-supports the burner blocks '23 and the attached furnace constmction.

In connection with the construction of the furnace proper, and as mentioned previously it should be noted that one of the prime requisites is the conservation of heat, it being wellknown in the art that the use of gas or oil fired burners require enormous amounts of air, which in turn is used to keep the burner cooled by the passage of air through and around the burner. This provides large amounts of excess air beyond that required for combustion purposes thereby creating the necessity of providing for discharge of the elementsof combustion and excess air which carries heat energy into the free air before it can be absorbed by the material being treated.

It would-therefore be highly advantageous -to provide a burner which did not require cooling by the air supplied for combustion, but could operate at the same temperature as that required within the combustion chamber. Thus, only enough heat units need be supplied to the 'material being treated as would be absorbed by it. The

furnace. structure proper of the present development advantageously does not require cooling by the air supplied for the combustion, but operates at the same temperature required within the combustion chamber. This is accomplished by providing the burner by casting a block of .perlite and refractory cement in proportion necessary to provide the required strength and firmness. In casting perlite and cement there is a tendency of the coarse and fine particles of perlite to. segregate thus making a casting of nonuniform particle distribution. Unexpectedly, by adding up to about 10% by volume of the total mix of a finely pulverized adhesive or sticky type clay, for example, bentonite, and stirring the mix dry, the clay coats the particles of perlite and cement. Upon the addition of water, the clay becomes sticky and causes the cement to adhere to the perlite and thereby produces a uniform casting. Of course, any preferred clay having the desired properties may be used. i

The burner includes the entrance manifold 24 and the interconnected distributing manifolds 25 and slots 26 which open into the furnace chamber directly under the furnace are directed upwardly toward the bottomof the center section 11 of the material passageway. Thus, when fuel sufliciently premixed for combustion is supplied to these openings and ignited within the furnace, the temperatures required were obtained andjonly a minimum amount of fuel is necessary as required by absonption ofthe material being treated. The top of the burner block 23 and openings 26 assume the same temperature of the combustion chamber, but heat transmission into the burner block is not permitted due to the insulationof the perlite in the casting.- The scavenged products of combustions, of course, escape through the openings 29 in the top 28 of the furnace.

It is also noted in the furnace structure proper, that a space is provided between the flat front and back tiles and the center section thereof which advantageously provides an effecting barrier against the transmission of heat to the outside tiles from the center section which operates within the furnace at high temperatures. a

Any conventional feeding means may be utilized to feed material to be heat treated to the device, and referring to Figure 2, a supply of ores, objects or minerals are fed from a hopper 31 into the vibrating feeder pan 30 which regulates the rate of feed delivered to the tile element of the passageway through-the furnace. A conventional vibrating device 32 is diagrammatically illustrated and the intensity of the vibrating device 32 is controlled by the regulator 33 which thereby controls the rate of flow of feed to the passageway. Since the vibrating device and its control elements are all old and well known in the art, no detailed description thereof is deemed appropriate or necessary, as previously mentioned.

Thus, particulate material is delivered by the feeder pan 30 to the refractory tile element 10. By means of the vibrations imparted to it from the vibrator 20, as previously described, the material passes over the surface of the refractory tile 10, through the furnace walls, across the interfitting or tongue and groove joint arrangement 13 and into the central portion 11 of passageway where it is subjected to the heat from the burner arrangement 23, the time of treatment being controlled by the intensity controller 22 which causes the material to travel either slow or fast, as desired. The rate of flow is thus regulated so that proper heat treatment is provided to the material in the central portion 11 of the passageway whereupon the material passes over the interfitting joint or tongue and groove arrangement 13 and through the back furnace wall over the surface of the refractory tile element 12 and is then discharged over the top of the material holdin means 14a into a conventional chute 37 for delivery to a conventional receptacle, not shown. Thus, material is fed to thematerial passageway through the furnace at a predetermined rate and is passed therethrough at a predetermined rate so that optimum treatment is accorded to the material being heat treated.

In connection with the passageway'through the furnace, it is noted that it is constructed of' a plurality of parts, namely, the front end section 10 receiving the feed, which should be long enough to begin beyond the front of the front furnace wall 34 for the purpose of receiving the feed from the vibrating feed pan 30 and .extend through the furnace wall to the center section 11 operating within the furnace, the center section being substantially equal in length to the inside length of the furnace where it joins to the third section which preferably is long enough to extend through the back furnace wall 34' and beyond far enough to discharge the feed into a suitable receptacle.

As best seen in Figure 3, the front end section 10 preferably is a refractory tile having walls along two sides and its outer end for the purpose of retaining the feed upon the surface of the tile. Preferably, the shape of the center section is determined by the product which will be treated. In most cases a wall is required on two sides to retain the products upon the top surface. ,In the event it is necessary to retain expansive material or a controlled atmosphere is required, it is contemplated that a roof would be included. Provisions for retaining the required atmosphere within the retort, muflie or hearth are within the skill of any one practicing the art and, accordingly, no detailed description thereof is deemed necessary. It is noted that the end or discharge tile 12 may have two sides, but that the end wall is omitted so that the material may be discharged over the end of the tile.

It is believed from the foregoing description of a presently preferred example of the invention, that the mode of operation thereof is apparent and need not be repeated. In short, the development comprises the provision of a passageway, for example, a ceramic mufiie,

retort or hearth, which is maintained in position by endwise compression by a cradle or other means which is independent of the furnace proper in that it is not attached thereto, but the cradle or other means is free to vibrate thereby vibrating the'passageway through a portion of the furnace. Thus, controlled rates of flow of material through the furnace and the heating zone is provided.

The present development may be applied to treatment of a wide variety of materials. For example, it may be used for heat treatment of metals, producing quick lime from oyster shells, dead burning gypsum or magnesite, expanding perlite, expanding vermiculite in either reducing or oxidizing atmosphere, as desired, in drying crushed ore and concentrates, for destructive distillation, j in the production of cedar oil or rice oil from rice hulls,

for the complete distillation of oil shale from crude, as well as many other uses which will suggest themselves to those skilled in the art. The present development advantageously has a very high capacity and acc ordingly;

eliminates the use of certain auxiliary equipment. For example, in drying crushed ores and concentrates, the high capacity eliminates the use of rotary kilns and dust collecting equipment.

The present development may be either of the stationary or portable type.

From the foregoing description it is obvious that the present development accomplishes the objects and has the advantages mentioned as well as others inherent therein.

While only a presently preferred example of the invention has been given for the purpose of disclosure, it is obvious that changes in details and construction and arrangement of parts may be made which are encompassed within the spirit of the invention and the scope of the appended claims.

What is claimed is:

l. A furnace for heat treatment of materials comprising, a furnace chamber provided with oppositely-disposed side walls, said side walls having openings therein, a refractory conveyor extending freely through said openings and through said furnace chamber, said refractory conveyor including a central section extending through said furnace chamber from points adjacent inner sides of said side walls and including end sections projecting from each end of said central section completely through said openings, interfitting portions on each said end of said central section and its engaging end of each of said end sections, said interfitting portions provided with space voids providing barriers against transmission of heat to the outside of the furnace chamber, and means independent of the furnace supporting the refractory conveyor in assembled position,,said means including a pair of compression members disposed exteriorly of the furnace chamber and engaging the ends of the end sections projecting through the openings and maintaining said pressive force. a

2-1 A, furnace .for heat treatment of. materials com prising, a furnace chamber provided, with oppositely-dis? posed side walls, said, side walls having openings therei arefrictory conveyor extending freely through said openings andfthroughsaid furnace chamber, saidrefrictory conveyor including a central section extending through said furnace chamber and endsections projecting from each end of the central section completely through said openings, interfittings portionson each end of said central section and on engaging ends of said end sections, anda cradle supporting said; conveyorindependently of said furnace chamber and disposed externally thereof, said cradle including a beam extending generally parallel tofsaid" conveyor, apairJofcornpression members projecting from said beam andeng'aging outer ends of the end sections projecting through said openings, adjustable means for moving at least one of said supports towardthe other whereby saidcornpression members maintain said refractory conveyor in position by compressive force, and means for vibrating said cradle and thereby said conveyor. 1 e

3. A furnace for heat treatment of materials com prising, a furnace chambenprovided with oppositelydisposed side walls, said side walls having generally horizontally-aligned openings, therein, a'refractory conveyor extending freely through said openings and said furnace chamber, said refractory conveyor including a central section extending through said furnace chamber from points adjacent inner sides of said side walls and including end sections projecting from each end of said central section completely through said openings, interfitting portions on each said end of the central section and its engaging end of each of said end sections, said inter-fitting portions provided with-space voids providing barriers against-transmission ofheat, to the outside of the furnace chamber,.and a cradle supporting said conveyor ifide'plendently of said furnace chamber and disposed externally thereof, said, cradle including a beam extending generally parallel to said conveyor, a pair of compressiori members projecting from said beam and engaging outer ends of the end sections projecting through said openings, at least one of said compression members adjustably arranged on said beam whereby said compressior'i members maintain said conveyor in position by compressive force, and means for vibrating said cradle and thereby said conveyor.

References Cited in the file of this patent UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,840,363 June 24, 1958 Reynold J Penrose It is herebfi certified that error appears in theprinted specification of the above -numbered patent requiring correction and that the said Letters- Patent should read as corrected below.

Column 1, line 38, for "lows" read --low--; line 54, for "macaaceous read --micaceous--; column '7, lines 6 and '7, for "r'efrictory" read re fractory--; line 11, for "interfittings" read --interfitting=-; line 27, after "openings' strike out the comma.

Signed and sealed this 7th day of October 1958.

( SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Paten

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