US1903118A

US1903118A - Kiln

Info

Publication number: US1903118A
Application number: US565502A
Authority: US
Inventors: Lester L Ladd
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-09-28
Filing date: 1931-09-28
Publication date: 1933-03-28
Anticipated expiration: 1950-03-28

Description

March 28, 1933u 1 L, LADD 1,903,118

KILN

Filed Sept. 28, 1951 2 Sheets-Sheet l L. L. LADD `March 28, 1933.

KILN

2 Sheets-Sheet 2 Filed Sept. 28

Patented Mar. 28, 1933 UNITED STATES LESTER L. LADD, OF LOCKPORT, ILLINOIS KILN Applicationled September 28, 1931. Serial No. 565,502.

This invention relates to tunnel kilns used in firing ceramic ware. f

Tunnel kilns may be classied as open iring kilns or mule kilns. Inthe open type of kiln, the combustion gases are discharged directly into the ware passage. In the mulile type of kiln, a refractory muiile wall'separates the Ware passage from the combustion chamber to prevent the flames and gases of incomplete combustion such as carbon monoxide from reaching. the ware.

The open type of kiln is very eficient but those heretofore in use have not been adapted for firing certain kinds of ware, such as 5 glost Ware, because the flames and carbon monoxide came into direct contact with the ware and discolored the glazed coatings.

The muiile type of kiln is not so eiiicient as an open kiln, but it is safer and more satisfactory for some purposes because the mufHe prevents the flames and combustion gases from injuring the ware.

The main objects of this invention are to provideV a tunnel kiln of the open type which approaches the safety of a mufHe kiln.; to provide improved means for withdrawing carbon monoxide from the combustion chamber and the ware passage to provide an improved forin of baille which will prevent the flames from striking the ware but which will permit communication between the combustion chamber and the ware passage; to'provide a baffle of this kind which will permit the roof of the tunnel to move freely when expanding and contracting under temperature changes; and to provide a construction of this kind which is adapted for use in connection with tunnel kilns of the straight or circular type. v

An illustrative embodiment of this invention is shown in the accompanying drawings wherein:

Figure 1 is a top plan of a circular tunnel kiln, to'which this invention is applied.

Figure 2 is an enlarged transverse vertical section of the kiln at the firing zone.

Fig. 3 is a horizontal section, taken on the line 3 3 of Fig. 2.

Fig. 4 is al fragmentary side elevation of one of the baille walls.

In the form shown, the kiln is of the circular type comprising an annular conveyer 1 movable through an open loading and unloading zone 2, and through an arcuate tunnel 3 having a preheating zone 4,'firing zone 55 5 and cooling zone 6.

The conveyer may be of the type shown in my co-pending application Serial 366,959 filed May 29, 1929 which has become Patent 1,842,411. It comprises an annular platform '60 7, provided with the usual aprons 8, and supported on an annular I-beam 9, to which is attached a mono-rail 10, which rides on a plurality of supporting wheels 10.1. Certain of the supporting wheels are motor driven for driving the conveyer.

The tunnel is supported on a fabricated metal frame structure comprising vertically disposed

angle bars

11 and 12, which are connected to

horizontal bars

13 and 14. The 70 upper ends of the bars 11 are secured against spreading by horizontal tie rods 15, which are disposed above the tunnel. Supported on the frame bars 14, are concrete floor slabs 16 disposed on respectively opposite sides of the 75 conveyer. Formed at the inner edges of these floor slabs, are troughs 17, which are filled with sand or other suitable sealing material adapted to coact with the aprons 8 to prevent the heat in the ware passage from reaching the bearings of the conveyer. Metal shields 18 form the inner walls of the troughs 17. Y

VIn the form shown, the tunnel 3 comprises a floor 19, side wall 20, and a roof 21, which define the preheating zone 4, firing zone 5 and cooling zone 6. Inasmuch as this invention relates primarily to the tunnel construcvion within the firing zone, the other zones have not been shown in detail.

The tunnel varies in cross section at different zones of the kiln. Extending through the tunnel is a central ware passage 22 through which the ware travelsin the direction of the arrow shown in Fig. 1. My copending application Serial No. 565,501, filed September 28, 1931, shows a tunnel Ventilating system which is well adapted for use in connection with a kiln to which this invention is applied.

The floor, Walls, and roof of the kiln may be made of various heat resisting materials such as brick, fire brick, tile, refractory, infusorial earth, and similar materials.

In the firing zone, the tunnel is formed to provide a pair of combustion chambers 23 located on respectively opposite sides of the ware passage 22. Fuel is delivered to these combustion chambers through nozzles 24 which extend into openings 25 in the side walls 20. The nozzles 24 are connected to manifolds 26 of a fuel supply system.

Located on respectively opposite sides of the waie passage in the firing zone, is a pair of battles, each of which includes a pair of vertically disposed

walls

27 and 28, which are mounted on the tunnel flo-or 19 and which are spaced from each other. Formed in these walls, are openings 29 to provide communication between the lower portions of the combustion chambers 23 and the ware passage 22. The openings 29 of the walls 27 are staggered witli respect to those `of the walls 28, so as to prevent the [laines from entering the ware passage.

The inner walls 27 have outwardly proj ecting ledges 30 which rest upon the upper ends of the walls 28. As shown in Figure 2, the upper ends of the baille walls are disjoined from the tunnel roof, so as to permit the roof to freely expand and contract under temperature changes. In order to prevent communication between the upper ends of the combustion chambers 23 and the ware passage, the baliie walls 27 are imperforate above the ledges 30, and the tunnel roof is provided with inclined aprons or shields 31 which engage the outer faces of the walls 27. These aprons 31 form, in effect, movable sections of the bali'le walls 27. They permit the tunnel roof t-o expand and contract but they prevent any of the combustion gases in the upper portions of the chambers 23 from passing into the ware passage.

Carbon monoxide, which is the most injurious of all the gases of incomplete compustioii, is very light and usually floats to the upper portions of the combustion chambers and ware passage. In order to skim olf this injurious gas, to prevent damage tothe ware, the tunnel roof is provided with a plurality of outlet pipes 32 leading to a manifold 33 connected to an exhaust fan 34.

In the form shown, the tunnel is provided with grooves 85 in the roof and floor of the firing zone so as to permit the insertion of an imperforate baille 36 if one is desired.

In operation, the ware is loaded lon the conveyer l in the zone 2 and it is moved successively through the preheating zone, firing zone and cooling zone of the kiln.

In the combustion chambers, the flames from the nozzles 24 strike against the

bafile walls

27 and 28 and are thereby prevented from damaging the ware within the passage 22. Most of the carbon monoxide within the combustion chambers rises to the top where it is trapped by the walls 27, aprons 31, and ledges 30. Some of the carbon monoxide may escape through the openings 29 but it would then rise to the upper part of the ware passage.

'Ilie exhaust fan 34 operates continuously and the lighter gases, including the carbon monoxide, are thereby withdrawn from the combustion chambers and the ware passage. With this improved construction, the ware passage is substantially free from any gases of incomplete combustion which would injure the ware.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that certain details of the construction shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims:

I claim:

l. A kiln comprising a tunnel having a ware passage and acontiguous combustion chamber communicating with each other attheir lower ends, a substantially imperforate battle separating the upper portions of said ware passage and combustion chamber from each other, and means at the upper end of said combustion chamber for withdrawing" the liohter combustion gases.

2. kiln comprising a tunnel having a ware passage and a contiguous combustion chamber, a vertical battle arranged between said ware passage and combustion chamber,

the upper portion of said baille being substantially impervious to gases, the lower portion of said battle being perfor-ate to permit certain of the combustion gases to enter said chamber, and a pair of vertical baffle walls arranged between said passage and chamber and spaced from each other, said bafiie walls having staggered openings forming tortuous passages providing communication between said chamber and ware passage.

4. A kiln comprising a tunnel having side walls and a roof defining a ware passage and a contiguous combustion chamber, a vertical baffle mounted on the iioor of said tunnel f and being perforated to permit communication between said chamber and passage, the upper end of said baffle being disjoined from said roof to permit said roof to freely exrdv: ware passage, and means for withdrawing CTI pand and contract, and an imperforate skirt Y depending from said roof and slidably en-y {raging one side of said baile so as to form a movable section thereof.

LESTER L. LADD.