US1556208A

US1556208A - Salt glazing and klin for same

Info

Publication number: US1556208A
Application number: US382002A
Authority: US
Inventors: Dressler Conrad
Original assignee: AMERICAN DRESSLER TUNNEL KILNS
Current assignee: AMERICAN DRESSLER TUNNEL KILNS; AMERICAN DRESSLER TUNNEL KILNS Inc
Priority date: 1920-05-17
Filing date: 1920-05-17
Publication date: 1925-10-06
Anticipated expiration: 1942-10-06

Description

c. DRESSLER SALT GLAZ` ING AND KILN Fon SAME Patented Oct. 6, 1,4925. g

UNITED STA coimann imi.

XILNS,

'ras i PATENT OFFICE..

f, omo, assxciioaro vannnrcan :onrssnnn TUN- mc., yor naw roux, n. .r.,vajconroaar1onor New Yoan.) i

sur euznliaann mn, ron sana.

I Annalen ma luy y17, semino. 382,602.

To all whom it may-concern.' y

Beit known thatLCNnyAn., a subject of the King f JGrreat Britain, and resident of Cleveland, in the'I county of Cuyahogal and State of Ohio,`have invented certain new and useful 'Im rofvementsun Salt Glazing and Kilns for ame, of whlch the following is a spet'zification.'

My present invention comprises lmprovements in construction and mode of opera.

tion devised with .the specific-object inr view of firing andl salt glazmgceramic ware m v a continuous tunnel kiln 'havin yfiring', glazing and cooling vzones formed y communieating sections offen elongated kiln.' chamber through which the ware is moved. l l

Whlle myy improved method of salt glazing may be carried-out in various forms of tunnel kilns I lrefera'bly employ for the purposes. mule .lriln of theinternal combustion chamber type disclosed, for example 1n my prior' Patents 1,023,628 and 1,170,428. A characteristic yfeature of this type' of kiln is that the heat transfer between the ware and the combustion chambersb which the ykiln is heated, is wholly ormain y b a convection current circulationof the iln atmosphere which is heated by contact. with lthe combustion chambers and imparts heat tothe ware and is therebycooled lIn firing and salt f glazing ceramic ware vin `a continuous tunnelf'kiln in accordance with the present invention, I maintaina re ducing atmosphere containing salt vapors in the glazing zone of the kiln chamber which is intermediate the heating up or main firing zone and thefcooling zone. v It is highly desirable to prevent any flow of ,the zone atmosphere/into the zones or klln'sec-l tions at either sideof the glazing zone, bef cause of the detrimental eiec't of the salt vapors on the combustion chambersin the firing zone and the 'cooling ipes inthe cooling zone, and also becauseit'is desirable 'to' maintain i. oxidizing atmospheres in these glazing l reducing gas atmosphere constituents tothe glazing zone, and withdrawing vaporsand gases `thus supplied and not` absorbed by tnc ware, without pas'sin them through the kiln zone at either si e of thesalt glazing zone. `In addition I maintain pressure conditions in the kiln-which prevent the lazing zone atmosphere from passin into t ekiln zones at yeither side of the g azing zone b'y diffusion or yby longitudinal flow, but do not materially disturbthe convection current circulation 'in the kiln zones at the sides of the glazing zone. The featureslof construction and method which I have devised fori/this purpose may be employed in carrying out other processes than salt glazing in continuouskilns. f j

The various features of novelty which characterize my invention are pointedl out with particularity inthe claims annexed to and' formingv a art yof this specifica-tion. For a lbetter understanding `of the invention, however, and the advantages possessed by it. reference should be had to the accompanying drawings and descri tive matter in which I have illustrated and escribed a preferred form of my improved tunnel kiln.

Of the drawings:

1, Fig. 1 is a somewhat diagrammatic plan in section of a kiln.

2.` Fio. 2 is a vvertical section of a portion of the kiln shown in Fig. 1, taken on the line'2-,2 of Fig. 1,

AndFigs. 3, 4, 5, 6 and 7 are transverse vertical sections taken respectively, on the iines V13 3, 4 4, 5 5, 6 6 and 7-'7 of The kiln A shown in the drawings, comprises an elongated chamber of which one end section A1, serves as aware heating or main firing zone, intermediate sections A2 and A"i serve as a glazing zo'ne, and the other end section A* is aware coolin goods enter the kiln at one en of the zone past a doorB which is normally closed, and lleave the kiln at its opposite end past the normally closed door C. As shownthe goods are moved throu h the kiln on trucks E running on track rai s DA. The heating zoneA of the kiln is laterally enlarged toprovide space for combustion chambers Il), one at each sidev of ther pathway for the zone. The

goods, and for tubular extensions Dz of thev i.

combustion chambers. The combustion chambers and thelr extensions rest upon benches A atthe sides of the kiln. The' jacent each gas burner 1s an inlet F for air rsup orting combustion. Each inlet Fy lea s from a corresponding air supply ltunnel F extending longitudinally of the kiln.

The su ply of airth1"ough -each inlet F is contro ed by a damper F2. The combustion chambers D ,and the general arrangement of the heating up zone of the klln shown is like that commonly employed in the well known Dressler tunnel kiln. It is to be noted4 however that my invention- Vin some of its aspects is not restricted to the particular kind of muiile heated kiln shown, ut may be carried out in open fire kilns as well as in other types of muftleheated kilns. v The glazing zone sections A2 and A8 have their roofs slightly higher than lthe roof of the heating up zone A1 to provide a gas collecting space of considerable capacity above the goods pathway. This gas collecting space is divided into compartments A7 which are open at their lower ends, by transverse barriers or fiat arches A8. Each of the compartmentsA7 is provided with one orinore stack outlets A opening through its roof. At each side of the glazing zone sections A2 and A and in open communication therewith are oneor more chambers A1". As shown the chambers A10 each receives combustible gas through burner ipes G3 connected Ato the as supply pipes throu hre y atin valves an l receives air or t e com ustion of the as Afrom the tunnel F through a correspon ing vertical passage F. Each of the vpassages F4 is rovided with a regulating damper F5. Sa t or other glazing agent to be vaporized by the combustion occurring in the chambers A10 is supplied to each of the latter lthrough a corresponding pipe K.

Advantageously, as in the particular construction shown, the roofof the cooling zone A* is elevated to provide a series of air colf lecting compartments A71 open at their lower endsto the goods pathway and separated from one another by barriers'or flat arches AaLf vThe air for cooling the ware passing through the zone Aenters the kiln at its exit end as through ports C in the door C. The air ths admitted and heated by contct with the goods collects in the various compartments A,71 and is withdrawn from each of the latter, exceptthe`- compartment A immediately adjacent the glazlng zone V0f section As by a pipe J. The latter runs valong the roof of the kiln and is connected` to each of the compartments beneath it. The end of the pipe J, adjacent the glazing zone is connected to the inlet of a fan I. The latter is connected by piping H to two deliveryl nozzles H1 opening one into one and the ot er into the second of the air supply tunnels F. These nozzles draw by an ejector action airtoo hot to pass the fans I from the compartment A71 immediately adjacent the glazing zone through vertical channels F3 in the side walls of the kiln. Air delivered by the fan I in excess of the burner requirements may be passed to a drier or otherwise disposed of through a branch ypipe 11.

With the apparatus described, trucks are introduced into the kiln one at a time at regular intervals past the door B. As each truck 'is thus introduced, the train of cars filling the kiln is advanced a car length, and

a truck with inishedwarethereon is ejectedl from the exit end of the kiln.. Any suitable means may be employed for eriodically pushing the carsinto the kiln an advancing i the train of cars filling the kiln. No means for accomplishing this are shown, as suitable means for the'purpose are well known and in commonfuse. As the goods are moved through the heating up zone A1 of the kiln, the ware is more or less gradually and uniformly brought up to the temperature necessary to completely mature the Iware. As shown the ware X is sanitary drain ltile stacked two lengths high on the cars,'but it` will be understood, of course, that the invention is applicable to other ware and other stacking arrangements than that shown. In its passage through the glazing zone section A2 and As of the kiln, the ware is subjected to the action of the burning gases and vaporized glazing agent passing into the kiln `from the chambers A1". By suitable manip-` ulating of the gas valves Gf and the air Idampers F5, the amount of gas burnt and the composition of the burning gases entering the kiln from the chambers A1ro may be regulated as desired. It is' ordinarily desirable to maintain a strongly reducing atmosphere in the glazinozone. rl`his can be done, of course with the apparatus shown by supplying insuiiicient air to the chambers AOfor the complete combustion of the gas supplied to those chambers b the burners G8. The gases and vapors a mitted to the glazing zone and not absorbed by the ware escape from the kiln through the vents A. The suction exerted by the latter on the glazing zone may be varied by adjusting the dempers A11 applied to the vents A9 as shown in Fig. 5. The distributed outlets for the air by which the ware is cooled i-n the zone A4, makes possible a very `desirable control of the temperatures in the cooling zone, and the special provision described for passing this air into the tunnel F insures the necessary draft out of each of the compartments A7' without subjecting the fan to the `be .of my invention, asset forth in the appendhigh temperature of theA air in the compartments A" immediately adjacent the high temperature section of the kiln. l

The apparatus shown was primarily devised for use in the so called salt glazing process in which the glazing agent employed is common salt, the vapors of which unite with the clay ware at its surface and along surface fissures to form silicate of soda. Salt glazing is particularly desirable because of the excellence of the glaze and the relatively low cost of the glazing agent. The use of such a glazin agent in a continuous tunnel kiln is possib e only wherein the kiln con` struction and operation is such as to prevent the glazing agent from contacting appreciably with the Walls of the combustion chambers` or other highly heated portions of the kiln structure which would be injured. or destroyed by an excessive coating of glazing material. It is highly desirable to prevent the condensation of salt vapors in the coolingzone of the kiln.

o prevent the from passing into e firing or coolin I so regulate pressure conditions in th that there will be a slight but continuous drawn versel of the latter. The air gently flowing influx of air into the glazing zonejfrom the portions of the kiln chamber at either side of the lazing zone. The air thus withrom the end portionso the kiln may be suppliedb leakage around thedoors at the ends of the kiln, or by special air inlet ports provided for thevpurpose. I so regulate the suction throu h the outlets A' that there is a gentle in ux ofair into .the glazing zone from either'end without creatlng longitudinal air currents vthrough the end portions of the kiln materially .moditying the convection current circulation in the end portions ofthe kiln chamber transinto t e opposite e'ndsvof the-glazin zone will unite in combustion, with the uc-ing sin the glazing zone with a resultant prouction of carbon dioxide. The end rtlons of the glazing zone atmosphere willt us con-v sist of streams of gas iowing upward to the`4 outlets A and containing more `or less carl' `bon dioxide.v .The` very existence in.A these yend streams of carbon dioxide, tends to retard the combination in combustion ofthe air in the end portions .of thekiln with. the

reducing gases in the glazing zone atmosvf -pheref In consequence the combustion currin inregular operation is in no wise exploslve 1n character, and with` the smalll "amount of air 'availablethe combustion is .relatively lnslgrnfcant 1n amountb 'rovlsio'n's While in` accordance with the of'the statutes; I' have illustrat and Vdescribed the best form of my invention now known to me, it `will be vapparent to those glazing zone atmosphere t each, end o saidv glaz' skilled the art that changes in form may made Without departing fromv the spirit end portion o f the kiln chamber and heating other portions thereof as required'tov glaze fire and then cool the ware in its passage through the chamber, maintaining a lreduc'- ing atmosphere containing a -vaporized glazing agent in )a high temperature glazing zone rtion o' the chamber. v

2. he method of glazing ceramic ware which consists in movin the 'ware' through an elongated kiln chamger, cooling an exit end portion of the kiln chamber and heating other portions thereof as required to 'l glazev iire and then, cool the ware in its passage through the chamber, su pl ing :i vaporized glazing agent toj a iilg rtemperature glazing zone portion of the' kiln' chamber,

withdrawinggases and vapors from thelasty mentioned n chamber portion and.y sup-l plying airto portions of the kilnchamb'er at l eaehend of said glazing zone portion.

3..The method `of `,salt glazing ceramic ware which consists in movin 'the ware through an elongated kiln cham r, cooling an exlt end portion of the kiln chamber and heating other portionsfthereof as 1re uired to glaze-re and then cool the ware 1n its passage through the chamber and maintainv in'g'an atmospherecontaining salt vapors in a high temperature glazing zone portion of the chamber.

4. The method of salt glazing 'ceramici Ware which consists vin movin the ware through an elongated kiln cham r, cooling an eint end portion of the kiln chamber andheatin otherportions thereof as reguirednto g azejreand then cool the 'ware 1n its assage through the chamber,A sup ly-` ging t vapors Ato a high" vtem rature g azingfzone portion of-thekiln c amber, withdrawing and vapors from the last 'mention kiln chamber portion and supply rtions ofthekiln 'chamber 'at` air to zone portion. 5. The method of vmaintaining different atmospheresin `successive .communicating zones or sections of an elongated 'kiln chamber 'through which material is' moved l.and in';w hieh.1t'ismainly heated by convection currents 'of thekil'n atmos here contacting with the material' andV wit a hot b o'dy or bodies'fat the-side ofthe pathway for vthe material, which consists in supplying gaszones or sections of'an elongated kiln chamber throu h which material is moved and inwhichit is heated mainly by convection currents of the'kiln atmosphere .contacting with Vthe material and with a hot body or bodies at the side of the .pathway for the material, which consists in supplying gaseous ingredients to the different zones to form the different atmospheres thereof, withdrawing ,gases from an *intermediate zone of said series, and maintaining pressure conditions in said kilns to prevent appreciable logitudinal gas iiow in the kiln chamber. l

7. In a mule heated kiln the combination with the kiln chamber and muiiie heating means therefor, of means for supplying ingredients to an intermediate high temperature of said kiln chamber for maintaining a reducing atmosphere containing a vaporized glazing agent therein, and gas outlets opening through the wall ofl said chamber to'said zone.

8. In\a mule heated kiln the combination with an elongated kiln chamber and muflle heating means therefor, of combustion chambers opening to the kiln chamber inv a high temperature zone thereof intermediate its ends, means for supplying fuel, air and a vaporizable glazing agentto said .combustion chambers so as to thereby supply a reducing gas atmosphere containing the glazing agent in a vaporized form to said zone, and gas outlets opening through the wall of the kiln chamber to the glazing zone vportion thereof.

" 9.y The combination witha tunnel kiln comprising a heating up zone, aY coolin zone. and an intermediatey glazing zone, an having combustion chambers 1n said heating up zone and cooling conduits in said cooling zone, of combustion chambers opening into the glazing zone portion of the kiln chamber, gas outlets formed in the kiln chamber wall and opening to the glazing zone portion of the kiln chamber, means supply. ing fuel and a vaporizable` glazing agent to the last mentioned combustion chambers, means supplying fuel to the first mentioned combustion chambers, and means for passing air through said cooling conduits into all of said combustion chambers.

10. A tunnel kiln provided with a main stack or fan and also having an auxiliary stack or fan independent thereof by which special gases and vapors which have been introduced into the kiln for special purposes may be removed therefrom without resort being had to the means for inducing the main draft.

11. A tunnel kiln provided with a main stack or fan and also having an auxiliary stack or fan independent thereof acting on the firing zone of the kiln whereby special gases and vapors which have been Introuced into the kiln for s ecial purposes may be removed ifromlthe ring zone without resort being had to the means for inducing the main draft before said gases or vapors have the opportunity of coming in contact with ware 1n other parts of the kiln.

Signed at Cleveland, in the countyof Cuyohoga and State of Ohio this 12th day of May A. D. 1920.

CONRAD DRESSLER.