US1720550A - Tunnel kiln - Google Patents

Description

July 9, 1929. w. L.. HANLEY, JR 1.720.550

l TUNNEL KILN j Original Filed Sept. l1, 1925 2 sheets-sheet 2 "www TDR

Patented July 9, 1929.

UNITED STJFES*- PATENT OFFICE.

WILLIAM LEE HANLEY, JE., 0E BRADFORD, rEnNsYLvAun-i.

TUNNEL KILN.

Application filed. September 11, 1925, Serial No. 55,6451 Renewed December 11, 1928.

lily invention consists in the novel features hereinafter described, reference being had to the accompanying drawings, which illustrate one embodiment ot the same, and a slight niodilication thereof, selected by me l'or purposes ot illustration, and the said invention is fully disclosed in the tolloi'vihg description and claims.

lilly invention is an` improvei'nent in tunnel kilns, or ovens, designed more particularly tor tiring coarse clay products, such as bricks, lire brick, tile, etc., although my invention is applicable to kilns tor lil-ing other classes of goods Whore found desirable or advantageous. My improved tunnel kiln is ot the type generally designated as a twin tunnel kiln, and provides tvvo parallel tracks extending longitudinally tln'oughout the length ot the kiln, upon which tivo series ot cars are `loaded with the brick, or other coarse clay products to be fired, and nioved in opposite directions, the bricks on each series ot cars being progressively heated during a portion ot their travel through the kiln, until they reach a tiring Zone, Where they are completely lired, after Which they are gradually cooled during the remainder ot their passage tirougli the kiln, the hot tired bricks carried by the cars o'l one track communicating their heat to the bricks on the cars ot the other track ino ving in the epposite direction, tor the purposeol ell'ectiiig the cooling ot the heated bricks, and the prehcating, water-smoking and oxidation ot the unlired bricks on the cars of the other track.

ln the construction of tvvin tunnel kilns, the initial outlay for the erection oil'V the saine, is naturally very high, as tliese kilns are approximately Ll0() teet or more in length, and it is extremely desirable to provide a construction oi" kiln which can be built at as low an initial. cost as possible. l have also found, by experiment, that in order to obtain such a high outp ut as will make tliekiln commercially practicable, and Warrant the enormous initial expense, it is essential that the 'following factors shall be provided. ller example, it is necessary to regulate the tcinj/ieratui'e ot the tiring Zone so that it shall have a temperature at the entering end, oli, say, from 1000O to 1Ll00O F., or less than a firing temperature, and a temperature at the outgoing end of the tiring Zone oit approximately 1800O to 2000o F., in order tl at the brick shall not be too suddenly exposed to liring heat, but shall gradually be brought to the desired firing temperature, so as to avoid injury to the product, and this 1n be tru@` as to the bricks on both lines ot cars passing in opposite directions. Obviously, theretore, the heat curve tor one tiring zone, must be the reverse of the heat curve of the firing Zone for the bricks on the cars on the opposite track. I have also toiunl that the most economical results are obtained by direct tiring in the tiring Zones, that is to say, by discharging products of combustion :trom the furnaces Whether thc incl ha gaseous, liquid or solid fuel. lt is, however, very urions to the unhredv brick to sub* ject it to the direct action ont the products ot combustion during the preheatling thereof, as it has a tendency to stain, and scuni the bricks, and 'furthermore the products oil conibustion do not contain iree oxygen, and therefore the proper oxidation of certain ingredients oi the clays troni which the brick and other coarseclay products are termed, is not effected.

ln carrying out n'iy invention, li employ a single or unitary tunnel structure, throughout the entire length of the kiln, which enables nie to secure a great economy in the construction. I also eliminate all longitudinal tlues vvhich greatly add to the cost olf construction and upkeep ot a kiln. l pron vide two separate tiring Zones into which the products ot combustion are delivered from a series of *furnaces under accurate and independent control, so that the heat curve or graduation ot heat can be ellected in each liring zone and in theopposite direction in one tiring zone from the other. T he tiring Zones are so located that the hott-est portion oit each, of said liring zones is adjacent to the hottest portion ot the other, and the tiring Zones may or may not be overlapped, as may be found most desirable. l also provide for the Withdraiival ot the products ot combos-- tion troni each `liring zone adjacent to each of the independently controlled 'turnaces, so that after 'the products ot combustion troni cach furnace have been directly brought in contact with the goods to he fired therein, tl ey Will be completely eliminated troni the kiln and their heat utilized tor drying groen brick in suitable dryers, or for heating the air' supplied to the furnaces, or otherwise, and is kept from Contact vvith the unlired bricks' Within the kiln; According to niy Vare subject-ed to gradually increasing tem- Vcapable of adjustment, and may several pipes or passages for the peratures to and including the firing tcmperature of the kiln, and then pass through the other firing Zone, where they are subjected to gradually decreasing temperature, substantially corresponding to the gradual cooling of the bricks, during which period they act as a sort of reservoir for absorbing excess heat at one point and giving it olf 'to the bricks on the other track if their own `temperature becomes higher than the temperture on the opposite side of the kiln, after which they pass through one of the cooling and preheating sections in which they give up their residual heat by direct radiation and by convection air currents in the presence of fresh atmospheric air to the `bricks moving 1n the opposite direct-ion on the other track, to effect preheating, watersmoking and oxidation, preliminary to the firing of said bricks, as the fired bricks are gradually cooled on their way to the discharge end of their tracks. This combined cooling' and preheating action takes place in both of the end sections ofthe kiln at opposite ends of the firing zones, and the resulting operation is a very rapid and eflicient- Lfiring of the products, insuring large output with a minimum cost of construct-ion and up-keep. The means employed for witl drawing the products of combustion from the liring zones, which will ordinarily he fans or other suitable suction means, are also be so regulated as to prevent the products of combustion from the firing zones passing through the preheat-ing and cooling sections of the kiln, and may also be caused to be withdrawn, in addition, a portion of the heated air from the preheating and cooling sectior, causing such quantity of air to be replaced by fresh air from the ends of the kilns adjacent to the doors by leakage, or otherwise, and insuring` the proper amount of oxygen in the preheating and cooling Zone.

In each of the heating zones I prefer to employ a longitudinally disposed baille wall interposed between the furnaces and the bricks which are to be fired, so as lo deflect the 'products of combustion toward the roof or crownV ofthe kiln and cause them to pass downwardly through the bricks as they are piled .on the cars, and I. prefer to provide vil'hdrawa of the products of combustion from each .tiring Zone adj acont-'to each of the furnaces and having their receiving apertures located one adjacent to the lower portion. of the baille wall, Aand others at other portions of the kiln, as in the centra-l longitudinal platform between the trucks on the two tracks. for example. anden the opposite wall of the kiln, said openings being substantially at or iff/20,550

slightly above the level ol' the trucks, and each of said pipes or passages beingpre 'erably under the control of indepeiulent regulating valves so that the temperature of cach portion of each liring zone can be regulated with very considerable accuracy by these valves in conjunction with the valves or other means which control. the individual furnaces.

Referring to the accompanyiinil illxanf'ings, which show several emhmlimenls of my invention, selected by me for purposes of illustration,

Fig. l represents diagrammatically a` horizontal section of the entire kiln enlluulying the invention showingr the two tiring zones disposed longitudinally with respect lo each other, without overlalnaing.

Fig. 2 is an enlarged horizonal sectional View, also diagrammatic, illustratilre` one oll the firing Zones.

Fig. l is an enlarged transverse vertical section on the line 3-3 ol Fig. l, through one of the firing Zones, in the direction ol' the arrows adjacent to said line.

Fin'. el is a view similar to Fig. l showing the nring Zones overlapping each other :u the hottest portion of each, so that the teniperature of the overlapping portions of the two firing zones will be substantially identical and will not effect the respective heat curves of the two tiring zones.

Fig. 5 is a view similar to Fig. .4. in which a central perforated wall extends longitudinally through each of the unitary firing zones.

Fig. G shows an enlarged transverse section on the line 6 6 of Fig. 5.

Referring to the forni of nly invention illustrated in Figs. l, 2 and 3, l, and l, represent the opposite end sections of the kiln which I term the cooling and preheal ing` .sections, while 2 and 3, represent the tiringl zones, which, as shown in Fig. l. are arranged longitiulinally with respect to each other between the preheating zones, so that no parts of the firing Zones overlap. The entire kiln structure consists of a, single unitary tunnel having side walls, 5. .7. and a single crown, (i. The outer portion of the length of the kiln may be ol ordinary brick., but I prefer to build the tiring zone sectioirs of tire brick, or other suitable refractory material. Two4 tracks, indicated respectively at 7 and 8, extend hmgitudinally and prei.'- erably in a straight line through the entire kiln, parallel to each other. on which are supported the Vusual tunnel cars, indicated at 9, upon which the bricks or other products to be lired. indicated diagrznnrnalically at l() in dotted lines, are supliorted, and said cars are caused to be moved continuously or intermittently as preferred, in any preferred manner in opposite directions on 'the tracks, 'l and S, the directions of movement lll) lll() of said cars on the respective tracks being indicated by arrows in Figs. l and Q. The kiln is preferably of very siinple and inexpensive construction entirely without longitudinal flues, which greatly add to the cost of construction, and in the preferred forni of iny invention the entire length of the kiln is a unitary chamber without either longitudinal or vertical intermediate walls or partitions of any kind wlnitsoever, with the exception of the baille-walls in 'the tiring; Zones, hereinafter referred to.

l will now describe one of the .tiring Zones, as the zone 2, illustrated in cross section in 3. Each of the tiring zones provided at one end thereof with a plurality of furnaces extenoing` side by side longitudinally of the kiln, indicated at 1 1, and discharging the products `of combustion through a passage, 12, between the outer wall and a. baffle-wall, or deflecting wall, 13, parallel with the outer wall and located adjacent to the nearest track on which are the cars carrying the bricks to be tired in 'this j iarticular firing Zone. This battle wall, 13, is provided at its upper end with an inwardly and upwardly extending' portion, 1li, forming` a deflector which directs the products of combustion towards the crown or roof of the kiln from whence they descend through the bricks to be fired imparting' heat thereto, after which they are witluilrawn frein the ring,- Zone. Any kind of fuel inay be employed. ln the present instance l have shown, diagrannnatically, burners, indicated at 15, supplied with gas, and air pipes, 1G, 17, respectively, extending' longitudinally of the zone, said burners being' under the control of air and gas valves, 18 and 19, respectively, so that the heating' effect of each furnace may be directly controlled and regulated. lf other fuel is employed, the saine or equivalent regulation inay be obtained by properly regulatinfc;` the supply of air and fuel thereto. Adjacent to each furnace l provide a pipe or passage, 2l), having an inlet aperture, 21, on the inner face of the baille wall above the level of the cars or trucks on the adjacent tracks, said pipes or passages being;` provided with regulating' valves. 22, and connnunicatiinr with a header or eduction pipe, 23, extending longitudinally of the kiln, and ,connected with a suction fan or other exha sting' device, indicated at 24, for the withdrawal of the products of combustion, of each furnace, after it has performed its lirinn effect on the `goods. ln seine instances l j nefer to provide a plurality of eduction ports, or openinns. located adjacent to each furnace, and at different portions of the kiln, for enabling the removal of the products of combustion to be inore cllicaciously accomplished, and to better control their effect within the Vlirinp;

Zone. For exainple, the usual central platform, 25, between the trucks on the two sides of tracks, is provided, and will extend through both firing Zones, and preferably extends throughout the entire kiln. lin some instances, as shown in Fig. 25, l inay provide an eduction port in said central platform, as indicated at 26, and a pipe or passage, 27, leading,l therefrom to the eduction pipe, Q3, and controlled by a suitable valve, 28. ln seine instances l .may also provide the wall, 5, of the kiln, opposite the baille-wall, 13, with an eduction port, 2t), and a pipe or passage, 3l), leading;` across, beneath the kiln, or beneath 'the tracks thereof, and connected to the niain eduction pipe, 23, au d controlled by a` suitable valve, 11, so that the products of combustion ina-y be reinoved at different points transversely of the kiln, adjacent to each furnace, and the cont-rol of the heat within the corresponding section of the firing Zone, is very accurately controlled in conjunction with the regulation of the supply of fuel and air to said furnaces. iks the construction of the two tiring Zones is exactly the saine, I have given the saine parts, of both tiring` zones, the saine numerals in F 1, 2 and 3.

ln the operation of iny improved kiln, it will be understood that there is a continuous line of cars at all times when the kiln in operation, on .each of the tracks 7 and 8, extending' freni one end of the kiln to the other, being; inoved in opposite directions either contiiniously or intermittently. Tracinge; the course of a j iarticular car of goods on one of the tracks, say the track, 7, freni` the time it enters the kiln until it leaves the saine,v the oj'ieration would be substantially as foikiws. lVhen the car enters the kiln, the goods thereon are unlired clay products, as they have como from the ordinary drier, and have found thenisnlves directly opposite to a car of fired brick, on track 8, which have become materially cooled and are aboutready to leave the kiln. The green bricks on the car on track are inoved gradually through the preheatinesection, l, of the kiln (see Fig. 1) and during;l their progress therethrough are gradually heated by direct radiation, and also by convection air currents due to the circulation of airin said preheating and cooling section, Ll, from the hot tired bricks on track, 8. so that the green bricks on track, 7, are gradually preheated in an atinosjihere containing); ample oxygen supply, and will be water-slnokcd and oxidized to the desired extent without sciunniin or staining', and at the time they reach ice uets of combustion therein, and as they pass through the tiring Zone they are raised to tiring temperature and fired, leaving the Bring zone at the highest tempera-ture thereof, say approximately 2000O F., more or less. lVithin the firing zone, 3, on the track, S, there will be a line of cars of fired brick which have left the ring Zone, 2, and are being gradually moved in a direction toward the cooling' and preheating zone, 1. These bricks are of course subjected, to a certa-in extent, to the products of combustion in the firing Zone, 3, and as they are moving in the opposite direction to the bricks on track, 7, theywill be permitted to gradually cool and at `each longitudinal point in the ltiring zone, 3, the temperature of these red bricks on track, 8, will be caused to conform substantially to the temperature of that portion of the tiring Zone. The tired bricks, therefore, after leavingv the tiring zone in which they were fired, and passing through the other firing Zone, act as a sort of reservoir of heat, and if their temperature is in excess Lof that of the products of combustion in the particular portion of the second firing Zone, through which they are passing, they will yield a portion of their heat, and vice versa, being gradually lowered in temperature as they move toward the cooling' and preheating Zone, 4. In like manner, the bricks Von track, 7, having been red by passing through the firing Zone, 3, act in the same way, while they pass through the firing Zone, 2, on track, 7 longside of the bricks on the cars on track, 8, which are being iii-ed in the iiring zone, 2, there being an equalization of heat at diiferent points in each tiring Zone between the products which are being fired therein, and the products which have been tired in the other firing zone. After leaving the tiring zone, 2, the bricks on track, 7, are gradually cooled as they pass toward the end of the preheating and cooling section, 1giving up their heat to the green bricks, on tracks, 8, moving in the opposite direction, until they are suliiciently cooled to be removed'from the kiln.

In Fig, 4 I have illustrated a slight modification in which the firing Zones, here indicated at 102 and 103, are slightly overlapped at their portions of highest temperature, and in order to facilitate the understanding of myinvention, I have indicated the temperatures at the entering and discharging ends ofeach .firing Zone in Figs. 1, 4 and 5, as 1100 and 2000 respectively, to indicate the rising` heat curve in each. I

wish itV to be understood, however, that thev temperatures which I have mentioned herein, are only mentioned as examples and that I do not limit myself to either the maximum or minimum temperatures herein referred to as` the actual temperatures, minimum as well as maximum, may be varied to a considerable extent in practice. It will he seen from Fig. il, that there will be substantially no different ell'ect produced by overlapping the hottest portions of the liring Zones, 102 and 103, as the temperature within the overlapping portions of the two firing Zones will be substantially the same as would be the case if they were not overlapped, and this overlapping of the firing zones, which may be convenient in some iustallations, does not interfere. with the proper and accurate regulation of temperature in the several tiring Zones in accordance with the desired heat curve. rfhe other features of the kiln illustrated in Fig. L1 are identical with those previously described and illustrated in Figs. 1, 2 and 3, and will not be further referred to or described. l` hey are given the same reference numerals with the addition of 100.

In Figs. 5 and G I have illustrated another slight modiiication of my invention, in which I have provided a. central vertical partition, indicated at 250, extending through the firing zones of the kiln and provided with apertures, 251 and 252, at approximately the level of the trucks and adjacent to the crown or roof of the kiln, respectively. The other features of the kiln are identical with those previously described, and will not be further referred lo or described. They have been given the same reference numerals with the addition of 200. The operation of the kiln illustrated in Figs. 5 and 0 will be substantially identical with those previously described, excepting that the radiation from the previously fired bricks on the track remote from the baille-wall will be through the partition wall, 250.' rI`he heat, transmitted b v convection by currents of the products of combustion being` substantially the same. as said products of combustion, will pass through the communicating apertures in the partition wall.

My improved kiln produces an extremely cheap and eiiicient construction lo build and operate, and will produce a very high output of tired clay products with an economy of fuel. The kiln also canv be kept in a high sta-te of el'liciency with a minimum amount of expense for repairs, to which the entire absence of longitudinal lines greatly contributes. It will also be seen that by means of the control of the furnaces and the rduction passages, a very accurate control of temperatures in each firing Zone according Y to the predetermined heat curve desired, can

be readily effected, and the products of combustion from each furnace are witlulrawn from the tiring zone adjacent thereto and entirely removed from the kiln, so that the, products of combustion do not pass into the preheating and cooling sections of the kiln at the end portions thereof, thus preventing lll) medew staining' and scunnning the bricks during the preheating thereof, and. also insuring the preheating and Water-smoking oit the bricks in the presence ot an adequate supply ot oxygen. The pipes or passages for the Witlnilraival ot the products ot combustion are preferably of more than adequate tor the uf'ithdrzuval of all oit' the products ot' combustion ot the furnaces, and hy properly adjusting' their controlling va lves, it is possible to Withdraw not only the products ot combustion from the tiring zone, but also considerable qilantities oit air ifroni the ad* jacent portions ot the preheating and cooling' sections ot the kiln, which will be replaced by fresh air entering around the doors et the opposite ends ot the kiln, and thus insuring'7 Where necessary, a sufficient supply ot oxygen in the prohosting andcooling` sections of the kiln.

llilhat l claim and desire to secure by lbetters Patent is l. A tunnel kiln having' a unitary tunnel structure throughout its length, the central portion of the kiln forming tivo consecutively arranged, unitary firing zones, and the opposite end portions ot the kiln torniw ing; unitary cooling and preheating Zones, said kiln being provided With parallel goods conveying means, movable in opposite directions, each of which passes through each ot said cooling and preheating Zones and each ot said tiring Zones, heating means for each of said tiring' Zones including direct tired furnaces discharging' their products et coinbustion into saidv tiring zones, the furnaces tor each tiring' Zone being' located on. the opposite side oi the kiln from the furnaces tor the other firing zone, ineans for independently regulating each of said tiu'naces tor each of said tiring' zones to maintain a gradually increasing.; temperature in each tiring Zone t'roin the entrance end thereof toward the other tiring Zone, each ot said. tiring; Zones being provided with eduction ports located. at different points `transversely thereof, and ineans connected with said eduction ports tor' withdrawing the products ot combustion.

2. A tunnel kiln having; a unitary tunnel `structure throughout its length, the central yportion oi' 'the kiln termina' two consecutively ar anged, unitary tiring' zones, and the opposite end portions of the kiln forming; unitary cooling and preheatingr Zones, said kiln being` provided with parallel goods conveying' ineans, movable in opposite directions, each oit Which passes through each ot said. cooling'- and prehcatinjg,` Zones and each of 'said tiring Zones, heating ineans tor each of said tiring;i Zones including' direct lired furnaces discharging' their products oit coinbustion. into said tiring zones, the furnaces for each tiring` Zone being located on the opposite side of the kiln troni the furnaces tor the other tiring zone, means :tor independently regulating each ot' said furnaces for each ot said :tiring` Zones to maintain a gradually increasing' temperature in each tiringV zone l'froin the entrance end thereot toward the other firing zone, each ot said tiring zones being' provided adjacent to each ot said turnaces with a plurality oit eduction ports located at separated points transversely ot the kiln, and ineans connected With said eduction ports for 'withdrawing products o l combustion from the adjacent Vtiringzone.

3. A tunnel kiln having a unitary tunnel structure throughout its length, the central portion ot the kiln forming` tivo consecutively arrann'ed, unitary tiring Zones, and the opposite end portions ci" the kiln forming; unitary cooling' and preheating Zones, said kiln being provided with parallel aa'oods conveying lneans, movable in opposite directions, each of which passes through each ot said cooling and preheating; zones and each of said tiring: zones, heating' means :tor each oit' said. .tiring zones including; direct tired furnaces discharging their products ot coin bastion into said tiring' zones, the furnaces il'or each firing' Zone boing located on the opposite side ot the kiln trein the furnaces 'for the other .tirinp- Zone, ineans tor independently regrul-ating` each oi. said furnaces tor each oit' said firing' Zones to maintain a gradually increasing.;` temperature in eachv tiring zone vtrono the entrance end thereof toward the other iring Zone, each of said tiring` Zones being provided with eduction ports located. at separated points transversely of the kiln, separate eduction passages connected with said ports Yfor Withd1ra-wing the products of' combustion troni each tiring` zone, and independent controlling; ineans ior each of said @duction passages.

4l. A tunnel kiln having a unitary tunnel structure throughout its length, the central portion o1E the kiln 'fornxinn' tivo consecu tively arranged, unitary tiring zones, and the opposite end portions ot the kiln torining` unitary cooling; and preheating zones, said kiln being' provided With parallel. ,(oode conveying); means, movable in opposite directions, each ot Which passes through each of Said coolingr and preheating zones and each ot said tiring zones, heating means tor each oi said tiring' Zones incliu'ling.;` direct tired furnaces discharging their products ot coinbustion into said tiring; zones, the :turnaces for each tiring; Zone being located on the opposite side oit the kiln from the furnaces i'or the other tiring Zone, rneans for independ ently regulating` each ot said furnaces for each ot said tiring Zones to maintain a gradually increasing,` temperature in each tiring' Zone lron'i the entrance end thereol2 toward the other firing Zone, each oit said tiring zones being provided adjacent to each o'l' its turnaces With a plurality of eduction ports lollt) cated at different points transversely of the kiln, `means for withdrawing the products f of combustion frein each of said iiring Zones connected-by independent passages with said eduetion ports, and independent controlling means for each of said eduotion passages.

5. A direct lired tunnel kiln having a unitary tunnel structure throughout its length, the central portion of the kiln forming tWo consecutively arranged, unitary lil-ing zones, and the opposite end portions of the kiln forming unitary cooling and preheating zones, said kiln being provided with parallel goods conveying means, movable in opposite directions, each. oi which passes through each oi said cooling and preheating zones and each of said iring zones, said Consecutive iiring zones being provided with longitudinally disposed vertical partitions located bet-Ween the parallel goods conveying means passing therethrough and provided with apertures therein 'for the passage olf the products of Combustion.

In testimony whereof I ailix n'ly signature.

VILLIAM LEE HANLEY, J 1:.

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