US930948A - Apparatus for burning portland cement. - Google Patents

Description

T-. A. EDISON. APPARATUS FOR BURNING PORTLAND CEMENT.

' APPLIOAIIUN FILED NOV. 26, 1906. I

930,948. i A Patented Aug.10,1909.

2 SHEETS-SHEET 1 '1. A. EDISON. APPARATUS FOR BURNING PORTLAND CEMENT;

APPLIGATIONIILBD NOV. 26, 1906.

Patented Aug. 10, 1909.

'IIIfIIIIlI/IIIJII i tron being TED STATES PATENT OFFICE.

monks A. EDISON, oF LLEWELLYN PAnnfonA cE," NEW JERSEY..

arranarusronnnnnrne ron'rnanncnmnnr. No.93o,94s. j Specification of Lette' rs'llPatent. resented Aug.10,.1909.

n uc uba filed mama, 21%, mos. a seriai.N 345,o41.

To'all whom it may concern; 1 .1 Be it known that I, TIIoMAsALvA EnisoN, a citizen of the United States,-lresidin-g at Llewellyn Park. Orange, countyofEsseX, and State ofNew Jersey, have-invented certain new and useful Improvements inaApparatus for BurningLPor-tland Cement, of which the following is a description; r My invention relates to an. improved ap} paratus for burning :Portlandcementof the type employing a long rotary slightly inclined kiln, fired at the'lower end and supplied with dry pulverized material or chalk at the upper end, the materialpassing slowly through the kiln' as the .latter isf-revolved, and being burned or clinkered in? transit so that it leaves the lower end of the kiln inthe form of hard clinker balls, which arexg'round to obtain the final product. I Herctoforathe burning of Portland cement in apparatus of this type has beeninost successfully effected by the combustion (of one or more streams of finely pulverized coal injected into the lower end of the kiln, theflair tosupport-combusgenerally drawn in through a cooling cylinder so as toabstract heat from, the cl-inkered material. i

It is a fact recognized by engineers that a rotary cement-kiln is probably the-most inefficient and wasteful industrial apparatus in use today, and its successful employment in this country is only possiblebecause of thelow price of: coal andthe comparatively hi gh price commanded for the finished -prodnot. The principal ca-use for the inefliciency of a rotary cement kiln isthat the body of material undergoing treatment-oc-- 'cupies a small portion'of the area of the kiln, so that enormous losses are incurred in the exit gases, which leave vthe kiln at "ahigh' temperature. Other losses are'incurred by reason of the ineffective heating of 'themae tcrial, since practically only a small propor tion of the surface ofthe load ofmaterial is subjected .to the heat, even if thejlo'ad'is turned byprajections from the lining, as heretofore proposed. Additional, losses are also due to the dissipation of heat by conduction. and-radiation through; and from the kiln walls. Furthermore,the gases derived from the: combustion'of pulverized coal are non-luminous and hence practically non-radiant. so that in passing practically uncon-1 fined thronghthe tubular flue which the kiln 3 presents, very ])O0l =COl1(llt1()DS are offered for imparting heat tothe material, except in the lowermost part of the kiln where combustionJtakes' place and the flame is lumilions and can impart its heat to the material Y-QI'fldlfililOllj l 'llhe'fact that by the combustion of pul- .verized coal a luminous flame is obtained "is the particular reason Why this fuel has been used instead of other sources ofheat, notwithstanding the cost of grinding the coal and the dangers incident thereto. Ithas been suggested thatproducer gas might be utilized in connection with a rotary cement kiln, but it wasrecognized that-with the exr sting apparatus such a source of heat could not e: effectively utilized, since the. flame obtained .by the combustion of would be substantially as non-lunnnous and non-radiant as that of a Bunsen burner. Hence it has'been considered impossible to effectively use producer gas ina rotary cement kiln, notwithstanding the great advantages that would be derived therefrom in the savin of ,the'cost of grinding and in the possibilltyi of usingsources offuel of very poor quality. a

:In anrapplicat-ionfor Letters Patent, filed October 24, 1906, Serial No. 340,299, I dis close a cement burning apparatus, consistingessentially of a rotary cement kiln, the. upper portion ofwhich equipped with wings or projections on the bore, whereby as the kilnis rotated the material in transit througlnthe same .will be showered'crosswise so as to fill the bore of the kiln with a cloud of therfine material,representing as ll'lllCll' ilS'hfllfOf the entire load, and with such a kiln I have described the use of an improved settling: chamber and filter by which I am enabled to eflectively separate from the draft, all of the fine material very considerable :economies in the fuel, since condltions are presented which approximate somewhat the ideal conditions of a blast furnace the flame and the hot products'of combustion being brought into direct contact with the fine material so as to heat the same by impingement, and the gases being also made luminousso as .to impart heat by radiationtlirouglioutitlie greater part of type, I :can successfully make use of proproducer gas blown out .of the kiln therewith. By means o'f such an apparatus I am enabled to effect duce'r gas, natural gas, and other gaseous sources of heat wlnch have been heretofore lmpractlcable 111' the art, owing to the nonluminous character of the flame derived described, prevents losses due to the carrying.

oil" of material withthe draft. a

In order that the invention may be better understood, attention is directed to the accompanying drawings, forming part of this specification, and .in which- .4 Figure 1, isa side elevation of a cement burning apparatus of the type disclosed in my said-application, and illustrating the employment of a gas producer in combination therewith; Fig. 2, an enlarged sectional view, showing a part of the lower end-of the kiln and illustrating the burner; Fig. 3, a section on the line 33 of Fig 1, illus tratingthe inclined wings used on the interior of the kiln for showering the material cross-wise through the same; Flg. 4,. a longitudmal sectional-view on an enlarged scale,

, showing the upper end of the kiln and filter;

Fig. 5, a section on the line 55 of Fig. 4, and, Fig. 6, a separate perspective view, showing the preferred arrangement for providing the showering wings.

In all of the above views, corresponding parts are represented by the same numerals of reference.

.Thekiln 1, as heretofore, is made of cast iron sections, the total length being preferably in the neighborhood of 150- feet and its internal diameter about five or five and one-half feet. 7 The kiln is supported on rollers 2, and is. maintained at a'slight angle so as to cause the finegmaterial or chalk to progress slowly along the same as the kiln is rotated. The firebrick lining 3 is of the usual construction and protects the cast-iron walls from the heat. The upper portion of the kiln, say, for. a length of-about fifty feet, is formed ofsections 44, which are considerably beyond the vertical line of the kiln, as shown in said fi ure, so as to maintain a cloudorshower of the fine dust filling substantially the entire bore of the kiln.

As shown in Fig. 6, the wings 5 are preferably formed integrally with certain of the firebrick blocks forming the lining, each wing being composed of two blocks arranged side by side, so that the wings constitute pockets or recesses in which the material will accumulate as the kiln rotates, and out of which the material will be showered, as explained. In this wa no unoccupied space is offered through which the fiame or products of combustion may pass in a non-luminous condition, but on the other hand, the flame, if sufiiciently extended) and prodnets of combustion will of necessity be brought into direct contact with the material. The inner edges of the wings 5 extend substantially in line with the-bore of the main portion of the kiln, so that in each of the outer sections 4, additional space is provided in which a considerable load of material may accumulate to more effectively abstract heat from the burning gas and products of combustion therefrom. By providing additional spaces in this way within the kiln, it is possible to increase the load of chalk which may be showered by the wings 5, so that a large part of the load may be maintained at all times in the direct path of the burnin gas and the products of combustion there rom. In this way, the gases are made luminous, as I will explain, so that the heat therefrom will be absorbed by radiation, as well as by direct contact. The u Jper end of the kiln opens into a chamber 6, rom which extends a stack 7, having a damper 8 therein, so that if desired, the products of combustion may pass up through the stack. The stack may also be used when the kiln is first fired, or in case of accident to the filtering apparatus. The pulverulent material or chalk is supplied to a bin 9 and is fed therefrom into the upper end of the kiln by a screw conveyer 10, as heretofore. Adjacent to the upper end of the kiln, is a settling chamber 11, comprising generally a rectangular structure, whose walls may be conveniently built of firebrick or cement.

Near the front of the filter is' a wall 12,

through which passes a flue 13, connected to the chamber 6, whereby the products of combustion, etc. from the kiln, will be directed into the central part of the filter. Extending longitudinally of the filter between the wall 12 and the rear wall are two vertical rows of plates .14, inclined at a very acute angle and made preferably of firebrick or cement. I supply to the two sets of plates a load of relatively coarse material, constituting a screening or filtering medium, and which may be composed of coarse sand or gravel or coarsely ground cement rock, the particles ranging preferably from to 1, of an inch in size, the thickness of the body of coarse material being about 111- inches. The filtering material will accumulate between which extends longitudinally of the main the inclined shelves, so as to form' a substantially vertical filter, presenting innumerable fine interstices and tortuous channels, throughwhich the draft may pass andan and, carrying with it the load ofsepara't'edl chalk or dust,isdepositedby the roller feed 15 onto a conveyer 17 of any suitable type,

by which it is conducted to an elevator 18,

(see FigQ-l') and iselevated bytlie latter and deposited upon a series ofiscreens 19, provided with checking shelves 20, so as to prevent the material "from passing too rapidly over the screens. By means ofjthe screens 19, the fine dust or chalk will fall into a chute 21, while the coarse material will be returned tothe hoppers 16 and be distributed through the latter by the conveyers 22. From the chute 21, thefine chalk is deposited into the path of the conveyer 23 portion ofthe filter between the two filterby which the fine material will be conducted to the bin 9, as shown. The main 'portion of,

the filter is'formed with an inclined botom, as shown, and constitutes a settling chztimber, which is of such a size relatively to the area of the kiln that the velocity of the products of combustion is materially arrested, so that the greater proportion of dust or chalk car'- ried therewith will deposit by gravity in thesettling chamber and be carriedolf by the conveyer 23and elevator 24 to thebin 9. The draft, after passing through 'tlie filter-. ing walls, escapes through two vertical openings 25, in the wall 1 2, and is sucked out from the front of the filter by a fan 26,'operated from any source of power, preferably an electric motor controlled by the kiln. man at the front of the kiln. Byfcreating a draft within the kiln through the agency of a fan operated by a readily controllable motor, the

draft is underl much better control than when created by the stack, asis now the practice, and it may be quickly varied by the kiln man to meet any ehangingfconditrons wlthm the kiln.

Arranged adjacent to the lower end oftlie' kiln is a' gas producer-27 of. a'nysuitable type, located beneath a b1n28, winch may contain coal. of poor quality, since PIOdlICQI gas can be generated therefrom of sufiicient purity for my purpose. It is, inlfaet, perfectlyfeasible by using a gas producer to effectively utilize coal of such poorquality that it could not possibly be employed in the old way. Leading out from the producer v is a gas' pipe 2!), from which leads a nozzle 30 mounted on a swiveled joint 31, sothat the nozzle may be directed into the kiln at any desired angle. The gas pipe 29 and nozzle 30 are preferably provided with, a

. protectinglining32 made of firebrick or other vitreous material so as to protect the metal from the heat of the gas, or if desired the'pipe and nozzle maybe made of a suitfecc d hr y- I 3 Although I describe and illustrate a gas IprOducerasa suitableso'urce of gassupply,

able. resistant material that will not beat;-

it will be understood that natural gas may be employedand that other combustible gas may be derived from other sources and by other means. I I

In operation, the fine material or chalk is fed to the kiln in the usual way, and in passing slowly through the same, will enter the 35 pockets formed by the enlarged sections4 of the kiln, so as to accumulate therein in large loads Within these pockets, the material will be engaged bythe wings 5,:1nd carried upwardly, so asto beshowered or scattered diametrically a cro ss- 'tl i e kiln and directly aeross the draft. By properly proportionlng the angle of the wings 5, this-showering of the material can be adjusted so as totake v place even afterthe wings havepassed the central vertical lme ofthe kiln, whereby the bore of, the kiln will be substantially occupied with a cloud of fine particles; falling through the same and across the path of the draft It is not absolutely necessary toen oc ploy the enlarged sections, since properly arr ranged and shaped projections might be tar ried in thev lining of the kiln, having substantially.- a' COHUHUQUS bore, but such'enlarged sectionsare desirable as they permit 1 5 large loads of the fine. material to accumu- "late therein, and thus allow a much larger mass of material to be presented tothe directefiect. of the flame and products of combustion.

bythe flame and products of combustion and nearly all of the heat will be absorbed by the material, so that the operation will be very economical. l urthermore, by impinging-the 1 5 heat therefrom will beabsorbed by radiation. From the kiln, the draft carrying withit, a relativelydargeproportion of fine dust, enters the settling fchaniber between the two filter walls. The area of the set.-

tling chamber is so great that thevelocity of the draft will be greatly reduced, so that av large portionof the chalk will be deposited by gravity in the settling chamber, and will i be carried to the bin 9 by theconveyer 23 and elevator 24. From the settling chain- I By thus showering the chalk across 110 .the kiln, it will be very perfectly acted upon her, the products of combustion pass slowly through the channels presented by the granular filtering material carried by the inclined plates 13,. the area presented by the filtering material being very extensive and Y permitting the products of combustion to seep relatively slowly through the filtering walls. By thus causing the products of combustion to pass slowly through the fine channels or pores presented within the filtering material, any excessively fine dust-like particles carried by the draft and which were not deposited in the settling'chamber, will be effectively separated and retained within the filtering material on account of the slow movement of the gaseous currents in the channels, and also because the channels are so tortuous that the dust particles in many cases would have to be lifted up against gravity, which the slow movement of the aseous currents is unable to effect. Prefera ly, I maintain the load of coarse particles in constant, but very slow, movement, so that the filtering body is constantly replenished, while at the same time, its porosity remains unchanged. A movement sufficient to effect a complete change of the filtcring walls in one hour will be sufficiently rapid for the purpose. Although the filterin'g material is thus in constant movement, the resistance offered by the filtering walls remains constant, so that the draft within the kiln will be always maintained in the most effective condition, without being subjectcd to objectionable fluctuations. As the load of coarse filtering material, (carrying v with it the fine particles separated thereby) is fed from the two filtering walls by ,the roller feeds .15, it will be returned to the screens 20 by theconveyers 17 and elevators 18. By means of these screens the very fine particles will be separated and will be conducted by the' chute2l to the eonveyer 23 and thence returned to the bin 9, While the coarse filtering material will be returned again to the trough 16 and by means of the conveyers 22 will be distributed to the upper end of the filter Walls, so as to once more .pass in transit slowly over the inclined shelves 14'.

Having now described my inventlon, what I claim as new and desire to secure by Let- .ters- Patent, is as follows:

1. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein at .the

' upper end thereof, means for showering the material diametrically across the kiln during its passage therethrough to the lower end thereof, and a filter connected with the discharge from the kiln, and presenting atall times a constant porosity, of a source of gas supply connected with the --lower endof the kiln, substantially as andfor the pur poses set forth.

2. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein, means for showering the material diametrically across the kiln and a filter connected with the discharge from the kiln and presenting at all times a constant porosity, of a gas producer connected with the lower end of the kiln, substantially as and for the purposes set forth.

3. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein, means for showering the material diametrically across the kiln, a settling chamber connected with the discharge from the kiln and of large size to permit the velocity of the products of combustion therefrom to be very greatly reduced, so as to effect a separation by gravity of the solid or dust-like particles, and a filter adjacent to the settling chamber and through which the products of combustion pass from the settlin chamber to effect a final separation of the ner solid or dust.- like particles carried in suspension, said filter presenting at all times a constant porosity, of a source of gas supply connected with the lower end of the kiln, substantially as and for the purposes set forth.

4:. In cement burning ap )aratus, the combination with a rotary kiln, means for introducing pulverized material therein, means for showering the material diametrically across the kiln, a settling chamber connected with the discharge from the kiln and of large size to permit the velocity of the products of combustion therefrom to be very greatly reduced, so as to effect a separation by gravity of the solid or dust-like particles, and a filter adjacent to the settling chamber and through which the products of combustion pass from the settling chamber to effect a final separation of the finer solid or dust-like particles carried in suspension, said filter presenting at all times a constant porosity, of a gas producer connected at the lower. end of the kiln, substantially as and for the purposes set forth.

5. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein, means for showering the material diametrically across the kiln and a filter connected with the discharge from the kiln and presenting a filtering wall or partition of granular material, of a source of gas supply connected with the lower end 0 the kiln, substantially as and for the purposes set forth. '6. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein,

means for showering the material diametrically across the kiln, a filter connected with the discharge from the kiln, and presenting a filtering wall or partition of granular mameans for showering the material diametric ally across the kiln, and a settling chamber terial, and means for effecting a movement E formed of blocks of refractory material, a

of the filtering material. of a source of gas supply connected with the lower end of the kiln, substantially as and for the purposes set forth.

'7. In cement burning apparatus, the combination with a rotary kiln, means for introducing pulverized material therein,

connected with the kiln, a part of saidsettling chamber being formed of a wall of granular material, constituting the filtering medium, of a source of gas supply connected with the lower end of the kiln, substantially as and for the urposes set forth.

8. In cement urning apparatus, the combination with a rotary kiln, means for introducing pulverulent' material therein, means for showering the material diametrically across the kiln, and a settling chamber connected with the discharge from the kiln, the opposing walls of said settling chamber being ormed of loose granular material and each wall constituting a filter, of a source of gas supply connected with the lower end of the kiln, substantially as and for the purposes set forth.

9. In a cement burning apparatus, the combination with a rotary kiln, of means for introducing pulverized material therein at the upper end thereof, means for showering the material across the kiln, during the passage of the material through the portion of the kiln through which the material is first progressed, said showering means being so constructed that the material is showered thereby across substantially the whole diameter of the bore of the kiln, and a source of gas supply connected with the lower end of the kiln, substantially as set forth.

10. In a cement burning apparatus, the combination with a rotary kiln, of means for introducing pulverized material therein at the upper end thereof, means for showering the material across the kiln, during the passage of the material through the portion of the kiln through which the material is first progressed, said showering means being so constructed that the material is showered thereby across substantially the whole diameter of the bore of the kiln, a filter connected portion of said blocks presenting integral pockets inclined at such an angle that in the revolution of the kiln, the material contained in said pockets will be showered across substantially the whole diameter of the bore of the kiln, substantially as set forth.

12. In cement burning apparatus, a Totary kiln therefor, provided with a lining formed of blocks of refractory material, a portion 'ofsaid blocks presenting integral pockets comprising side walls and an inclined front wall, as and for the purposes set forth. 7

13. In cement burning apparatus, a rotary kiln therefor, provided with a lining formed of blocks, of refractory material, pairs of said blocks presenting conjointly inclined inclosing wings or pockets, substantially as and for the purposes set forth.

let. As a new manufacture, a block for the lining of a rotary cement kiln, presenting a portion of an 'inclosed pocket, the bottom of which constitutes an inclined wing, as and for the purposes set forth.

15. In cement burning apparatus, the comcharge from the kiln and through which the products of combustion are caused to pass, means for removing from the filter the fine material accumulated thereby, and means for returning such fine material to the bin, as and for the purposes set forth.

16. In cement burning apparatus, the combination with a rotary cement kiln, and a bin for supplying pulverized material thereto, of a settling chamber to which the products of combustion from the kiln are directed and in which a portion of the solid matter carried thereby will be deposited by gravity, means for returning the solid material to the bin, a filter through which the products of combustion pass after leaving

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