US1556260A - Construction and operation of tunnel kilns - Google Patents

Description

Oct. 6, 1925. w

R. w. STEERE CONSTRUCTION AND OPERATION OF TUNNEL KILNS Filed June 18, 1920 K I. g i

Patented Oct. 6, 1925.

UNITED STATES PATENT orrlcn.

'RO'BERT W. STEERE, 0F PROVIDENCE, RHODE I SLAND,'AS'SIGNOR TO AMERICAN DRESS- LER TUNNEL KIIiNS, INCL, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Application filed June 18, 1920. Serial- Ho. 390,012.

To all whom it may concern:

Be it known that I, ROBERT W. STEERE, citizen of the United States, and resident of Providence, in the county of Providence and State of Rhode Island, have invented oer-- tain new and useful Improvements in Goristruction and Operation of Tunnel Kilns, of which the following is a specification.

My present invention relates 'to continuous tunnel kilns and has to do with the injection of solid material into the kiln chamber in a finely divided foiq'm for the purpose of modifying the character, or at least the iappearance of the Ware passing through the (iln.

My invention was primarily devised for use in flashing brick in their passage through the tunnel kiln in which they are burned. To accomplish'this in accordance with the present invention I-discharge powdered coal into the kiln chamber at a point wherein the brick are at, or near their maxi-.

mum temperature. To increase the surface coloration, or rather discoloration produced by the powdered coal I may mix with the latter some other substance such as chloride of sodium or potassium. My invention is applicable to various types of kilns and particularly both to open fire and mufile kilns.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to v v and forming a part of this specification. For a better understanding of the invention, however, and the advantages possessed by it reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described some of the forms of apparatus by which my invention may be carried out.

Of the drawings;

Fig. 1 is a diagrammatic plan of an open fired tunnel kiln.

Fi 2 is a section taken on the line 2-2 of Fig. 1. Y

Fig. 3 is a diagrammatic elevation with parts broken away and in section of a muffle heated kiln.

Fig. 4 is a section on the line H of Fig. 3; and

Fig. 5 is a sectional elevation of the means employed alike in Figs. 1 and 2, and Figs. 3 and 4t and for injecting solid material into the kiln chamber.

In Figs. 1 and 2 I have illustrated the ing zone of the kiln.

use of m invention in connection with an open fire kiln comprising an elongated kiln chamber A with an entrance door B at one end and an exit door B at the opposite end. The brick to be fired or other ware to be heated in the kiln are-carried through the latter on the usual cars D running on track rails C. At an intermediate portion of the kiln burner chambers E are formed in the side walls of the kiln chamber. These receive air through inlets F from air supply conduits F. As shown the air supply conduits F are supplied with heated airby means of fans or blowers G which draw the from which they pass through the outlet M to a stackM which provides the necessary draft. I

Powdered coal, or a mixture of powdered deal with common salt or other finely divided solid material is discharged into the kiln chamber through inlets A in its side wall. These inlets open to the kiln chamber adjacent, but at the exit side of the burner chambers-F. The solid material 'is passed to the inlets A through an ejector nozzle I into which an air blast nozzle J projects. The coal or othersolid material is passed into each nozzle I through an inlet 1 from a hopper K to which the solid material is asse from a second hopper K at a reguated rate, as by means of a screw conve or K. It will be understood that the mec anism shown for passing the solid material into the kiln chamber through the inlets A is substantially like that employed for blowing powdered coal into furnace chambers heated by the combustion of such fuel and that the particular kind of apparatus shown in a somewhat diagrammatic manner for thisv purpose may be replaced by other known or suitable forms of a paratus. A damper controlled stack out et L opens chamber 'to the entrance end of the latter through the roof of the kiln chamber adjacent the inlets A for withdrawing gases and vapors from this section of the kiln chamber. Instead of using a jet of air to carry the coal into the kiln chamber,- a jet of other fluid as a mixture of air and gas or steam may be employed.

In the contemplated mode of use of the apparatus shown in Figs. 1 and 2 in flashing brick, the brick entering the kiln chamher past the door B are moved gradually through the kiln chamber. As the br ck passes from the entrance end of the k1ln chamber to the portion of the latter at which the burner chambers are located, they are more or less gradually heated up, and the brick are at practically their maximum temperature when they pass into the zone of the kiln chamber receiving powdered material through the inlets A. The powdered coal, or mixture of powdered coal and salt, blown into the kiln chamber through the inlets A should be thoroughly dispersed in the kiln chamber. For this purpose the inlets A' are flared, and the discharge end of the nozzle I is tapered, as shown, but other known or suitable expedients may be employed for causing the dispersion of the solid particles carried into the kiln chamber. The air blast by which the solid material is carried into the kiln is preferably restricted in amountso that the coal particles will burn with a reducing flame. The burning particles of coal impinging on the surfaces of the brick and entering the interstices in the surfaces of the brick which are ordinarily ve rou h I reduce brick constituents at the surface of the brick and thus eflect some discoloration. In addition the ash constituents of the coal melt or produce molten slag which produces a further discoloration of the brick surface. Salt or other material mixed with the coal and vaporized by the heat in the kiln chamber also produces its appropriate color marking on the surfaces of the brick. Excess vapors or gases produced in the zone of the kiln chamber into which the powdered material is discharged, are withdrawn through the stack L, the suction effect of which may be regulated by the damper L. V It will be understood that the invention can be used in connection with other types of open fire tunnel kilns than the one more or less conventionally illustrated in Figs. 1 and 2. The invention may also be used, with the special advantage in connection with muflle heated kilns, such as the kiln of the Dressler type illustrated by way of example in Figs. 3 and 4. The kiln shown in Figs. 3 and 4 comprises an elongated kiln chamber AA, having an ante chamber A at its entrance ehd and an exit chamber A at its o posite end. Doors (not shown) are ordinarily provided at each end of the kiln chamber. The brick or other ware to be treated in the kiln chamber AA are moved through the latter on cars" DA runnin on track rails C. Combustion chambers are provided in the kiln chamber along an intermediate portion of the latter. These combustion chambers rest on the masonry benches A at the sides of the track rails C. To the exit end of each combustion chamber is connected a group of tubes N which run to the entrance end of the kiln chamber and are there connected to a corresponding header N The headers N are connected, as by means of a tunnel N, to a suitable draft creating device which, as shown, is a stack M. Gas or other fluid fuel is supplied to each combustion chamber adjacent its head end through one or more burner inlets R, of which two are shown. Air to support the combustion of this fuel is supplied to each combustion chamber through branches Q of conduits Q formed partly in the benches A and partly above the benches A. The conduits Q, receive air through the duct P which is shown as being supplied with air by a fan or blower PA. the latter receiving air from a duct 0 The latter, in turn receives air from headers O to which are connected the air traversed pipes 0 running through the cooling zone of the kiln. The air which may be drawn into the pipe 0 from the atmosphere abstracts heat from the cooling zone of the kiln and is thereby heated while at the same time cooling the ware as the latter moves toward the exit end of the kiln.

Powdered coal or other solid material is introduced into the zone of the kiln chamber AA lying between the combustion chambers N and the cooling pipe headers O. The powdered fuel passes into the kiln chamber through inlet openings A which are flared and are supplied with the powdered coal or other solid material through nozzles I of apparatus shown as identical with that employed in Figs. 1 and 2 for discharging solid material into the kiln chamber A. Excess gases and vapors generated in the kiln chamber by the combustion or heating of the solid material injected may be withd awn through a stack L as in the construction first described. Those skilled in the art.will understand that the invention is useful in surface finishing various kinds of ceramic ware, and by the term ceramic ware I mean to include all clay and shale products which, like brick or sewer pipe for example, are advantageously surface finished by flashing or salt glazing.

While in accordance with the provisions of the statutes I have illustrated and described the best modes of carrying out my invention now known to me it will be apparent to those skilled in the art that many changes may be made in the form of the apto first raise the ware to a maximum temperature and then to cool the ware as the latter is moved through the kiln chamber from one end to the other, and injecting a finely divided solid material into a high temperature portion of the kiln chamber to thereby produce surface markings on the ware and restricting the dispersion longitudinally of the kiln out of said high temperature kiln portion of said solid material and the gases formed therefrom".

2. The method of burning and surface finishing ceramic ware which consists in passing the Ware through an elongated kiln chamber of a continuous tunnel kiln heated to first raise the ware to a maximum temperature and then to cool the ware as the latter is moved through the kiln chamber from one end tothe other, which consists in injecting a finely divided solid combustible material into a high temperature portion of the kiln chamber bymeans of a fluid jet, to thereby I roduce surface markings on the ware and restricting the dispersion longitudinally of the kiln-out of said high tem perature-kilnportion of said solid material and the gases formed therefrom.

a 3'. The combination in a continuous tunnel kiln comprising an elongated kiln chamber and means for heating said kiln chamber, of means for injecting into and dispersing in a high temperature portion ofothe kiln chamber, a finely divided solidsmaterial and means for restricting dispersion longitudi nally ofthe kiln out of said high temperature kiln portion of said solid material and the gases formed therefrom.

4. The combination -with the elongated kiln chamber of a continuous tunnel kiln, of means for blowing powdered coal into a portion of the kiln chamber intermediate its ends and means for restricting dispersion longitudinally of the kiln out of said high temperature kiln portion of said solid material and the gases formed'therefrom.

5. The combinationin a continuous tunnelkiln comprising an elongated kiln chamber and muffle heating means therefor,.of means for injecting finely divided solid material into and dispersing it in a high temperature portion of the kiln chamber and means for restricting dispersion longitudinally, of the kiln out of said high tem erature kiln portion of said solid material and the gases formed therefrom.

6. The combination in a continuous kiln,

of an elongated kiln chamber having a'vapor outlet from an intermediate high temperature portion of the kiln chamber and means for injecting finely divided solid material into and dispersing'it in said intermediate portion of said kiln chamber and means for restricting dispersion longitudinally of the kiln out of said high temperature kiln portion of said solid material and the gases formed. therefrom.

7. An open fire 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. Y

8. An open fire tunnel kiln provided with a main stack or fan andalso having an auxiliary stackor fan independent thereof acting on the firing zone of the kiln whereby special gases and vapors which have been introduced into the kiln for special purposes may be removed from the firing zone without resort being hadto the means for inducing the lnain draft before said gases or vapors have the opportunity ofcomingin contact with ware in other parts of the kiln. Sgned at 171 Madison Ave, in the county of ew York and State of New York this first day of June, A. D. 1920.

ROBERT W. STEERE.

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