US1898776A - Method and apparatus for burning cement - Google Patents

Description

Feb. 21, 1933. R. w. P. HORN ET AL METHOD AND APPARATUS FOR BURNING CEMENT 2 Sheets-Sheet 1 Filed Sept. 22, 1927 Feb. 21, 1933. R w p N ET AL 1,898,776

METHOD AND APPARATUS FOR BURNING bEMENT Filed Sept. 22, 1927 2 Sheets-Sheet 2 Patented Feb. 21, 1933 Uilllfil) STATES T ROBERT W. P. I-ZORN, OF ALLENTOVN, AN'D JACOB H..NISSLEY, 0F MANHEIM, PENNSYLVANIA METHOD AND APPABATUS'FOR BURNING- CEMENT Application filed September 22 1927. Serial No. 221,332.

This invention relates to a method and apparatus for burning cement or similar materials. As heretofore generally practiced, cement is usually burned in an inclined rotary kiln open to the atmosphere, the necessary clinkering temperature being maintained by injecting fuel into the end of the kiln opposite to that which is in communication with the usual stack. This arrangement is highly inefiicient in practice, because incomplete combustion takes place in the kiln due to the fact that excess air enters the kiln and interferes with complete combustion. Moreover, so far as known, no successful effort has heretofore been made to utilize the heat in the clinker before its discharge from the kiln, the general practice being to simply dump the red hot clinker from the kiln.

The primary object of this invention is to provide a method of operating a kiln so that great economies in the consumption of fuel may be obtained. To this end, means are provided to absolutely control the quantity of air, as well as fuel, that enters the kiln, and to so distribute the air as to secure substantially complete combustion within the kiln.

A- further object of the invention is to utilize the heat in the clinker to substantially raise the temperature of the air that is admitted to the kiln.

A further object of the invention is to provide a rotary kiln embodying means to discharge the clinker without admitting substantial quantities of air to interfere with the control of the air supply to the kiln.

A further object of the invention is to provide a kiln, in which fuel is supplied intermediate the ends thereof, that includes means to retard the movement of the material longitudinally of the kiln at the point at which the fuel is admitted.

A still further object of the invention is to provide a kiln including means to con trol the supply ofair to the interior of the kiln and in which a part of the air is utilized to retard the escape of finely divided solid particles with the gaseous products of combustion through the stack.

Still further objects of the invention will appear as a description thereof proceeds with reference to the accompanying drawings, in which, V

.Figure 1 is a side elevation of the im proved kiln.

Figure 2 is a longitudinal section of the feed end of the kiln. I

Figure 3.is a longitudinal section of the converging portion of the kiln. Figure l is a longitudinal section of the discharge end of the kiln.

Figure 5 is a transverse sectiontaken on the plane indicated by the line 55 of Figure 3.

Figure 6 is a transverse section taken on the line 66'of,Figure 3.

Figure 7 is a transverse section on theline 77 of Figure l on a reduced scale.

Figure 8 is a transverse section taken on 79 the p lane indicated by the line 88 on Figure 4. Similar reference characters indicate like parts throughout the several figures.

In the drawings, 1 indicates the rotary 7 kiln as a whole. As clearly shownin Fig. 1, said kiln comprises a main section 2 and a cooling section 3 connected together by a throat section 4 of reduced diameter as compared to said main and cooling sections. 80 Section 3 is provided with a tubular extension 5 for a purposeepresently to be described. Portions 2, 3, 4 and 5 are secured I I together to rotate as a unit. The kiln is provided with tires 6 that extend peripheral- 35 lytherearound at intervals throughout the length thereof It is supported for rotation on rollers 7 carried by foundations 8 of any approved type; 'A girthgear 9 surrounds section 2, said gear being arranged to mesh with a suitably supported driving pinion 9 to rotate the kiln. 1 in well known manner.

One cndfof main section 2 extends into a suitable brick housing 10 the interior of which is in communication with a stack 11. A feed conduit 12 having ahopper 13 at one end extends through said housing 10 into the main section 2 of the kiln. Said conduit may be provided with a spiral conthroat section a is veyer of well known form to provide an even feed of raw material to the kiln in well known manner, if desired.

The main section of the kiln adja cent n16 provided with a wall of increasing thickness from adjacent the midportion of said section continuing to the throat section. Preferably, such varying thickness is obtained by a plurality of steps 14. In order that the flow of the material through the kiln may not be interrupted to an objectionable degree, adjacent steps are 17 to prevent the clogging of the material in said ports. Preferably, but not necessarily, four ports are provided, arranged in pairs at diametrically opposite portions of the kiln but in staggered relation endwise of the kiln as clearly shown in Figure 3.

Extension is divided by walls 18 and 18' to form two chambers 19 and .20. A tube 21 is secured to the outer wall of chamber and extends axially of the kiln. A plate 22 closes the end of tube 21, said plate being provided with a glass peep-hole 23. Spaced from plate 22 are a pair of concentrically arranged spacing rings 2a and 25 separating tubes 26 and 27 that are arranged within tube 21 and concentrically therewith. Tube 27 opens into the chamber 19 as'clearly shown in Fig. at. Tube 26 extends into the end of cooler sect-ion 3 and is provided with a nozzle 28 having a plurality of-openings 29 arranged to direct air at a substantial angle to the axis of the kiln.

Section 5 and tube 21 rotate as a unit with the kiln, a tire 30 being provided adjacent the end of said tube. Said tire rests on a pair of rollers 31 supported by a foundation 32 in well known manner.

Surrounding tube 21 is a stationary casing 33 relative to which the tube 21 rotates. In order to reduce the friction between said tube and said casing, roller bearings 34 and 35 are provided between the ends of said casing and a brass wearing shell 36 that surrounds tube 21. As shown in Fig. 4, the outer wall of casing 33 is spaced from shell 36 providing an annular space between said shell and easing. Suitable packing glands 37 and 38 bear against shoulders 39 and 40 and are clamped there-acainst by rings 11 and 42 that may be adjusted by bolts 43 threaded in the end walls of said casing 33 and engaging said rings at intervals.

The annular space between packing 37 and 38 is divided midway between its ends by a series of loose annular sealing plates 44 arranged in grooves 45 of casing 33 and in grooves provided by sleeves 16 secured to shell 36 in any known way. connected to a suitable source of low air pressure combined with fluid or finely divided fuel of any form, such oil or powdered coal, for example. Ports 48 formed in tube 21 and shell 36 putthe annular space to which the pipe 47 is connected in communication with the annular space between tubes 27 and 21 adjacent the rear ends of said tubes, ring l9 being provided to divide said space into two sections. Suitable openings 50 are pr vided in tube 27 whereby the fuel under pressure is permitted to enter the annular soace between tube26 and 27 and to flow therethrongh to chamber 19.

A pipe 51 c nnected to any suitable source of continuous or pulsating air under pressure is connected to theannular space forwardly of rings 44. Ports 52 place this space in communication with the annular space between tube 21 and 27 forwardly of ring 49. Air under pressure is thus supplied to the chamber 20. I I

From chamber 20 air under pressure is conveyed lengthwise ofthe kiln by a plnrality of mains 53. At intervals along the len h of the cooler section, nozzles ea are i provided. Said nozzles are inclined in the direction of the upper end of the kiln. Further air nozzles 55' supplied with air from mains 53 are provided in the main kiln section inthe converging portion thereof, to supply air in the zone of the primary combustion. Further nozzles 56 supplied main 53 are arrangedin the main section between the converging sec ion and the stack. The several air mains 53 communicate with a bustle pipe 57 that surroui'ids the kiln adjacent housing 10. A, plurality of air ports 58 converging toward the axis of the kiln are arranged around he kiln with the axis of their openings in substan tially the same plane.

Communicating with the fuel chamber 19 are a plurality of fuel lines 59 (see F Said lines communicate with a fuel bustle pipe 60 surrounding the throat portion of the kiln. From said pipe the fuel is conveyed to the fuel ports 16 by conduits 61 and 62. I

Adjacent the end of the cooler section 3 a plurality of delivery sections and 64; are provided. These sections are annular chambers that surround the cooling section of the kiln as clearly shown in Fig... l and 7. The cooling section is provided with openings 65 and 66, the one opening communicating i "h the section 63 the other with ection 64:. clearly shown on the drawings, said openings are on diametrically opposite sides of the kiln. Hinged covers 67 provided with chains 68 to limit their opening movement are provided to close opening 65 and 66. Sections 63 and .6tare provided with A pipe 47 is external openings that are diametrically op- The raw material is supplied to the kiln through the spout 12. Air under high pressure is supplied to the chamber from the pipe 51 as above described and fuel combined with air under low pressure is supplied to the chamber 19 from pipe at as above described. The fuel is conveyed from the chamber 19 to the fuel port 16 by conduit 59. At the same time, air is supplied under pressure to the nozzl s 54. 55, 56 and 58. Combustion is initiated in the converging section of the kiln and rotation of the kiln is started. Inasmuch as the supply of fuel and air is under control of the operator, the quantity and pressure may be varied so hat substantially complete combustion of the fuel takes place in the main section of the kiln.

The material moves along the kiln under the action of gravity and its movement endwise of the kiln will be retarded at the con-v verging section thereof. At this point, the combustion occurs at its maximum intensity and the material is burned to clinker. The products of combustion pass to the stack 11. The converging jets of air that enter the kiln through the ports 58 substantially prevent the finely divided solid particles resulting from the burning of the material, from entering the stack by causing said particles to move toward the Walls of the-kiln. Said particles are disposed on the raw material entering the kiln and pass out with the hot clinker.

The clinker enters the cooling section through the throat section in highly heated condition and it gravitates along that section until it reaches the openings or 66 leading to the delivery sections 63 and 64. As it is moving along said section the air entering the nozzles 5d passes over the hot clinker and is highly heated before entering the combustion zone in the main section. The temperature of the clinker is thus reduced, while the temperature of entering air is raised. Further air is sucked into the cooler section through openings 29 in nozzle 28, said air entering the tube 26 through ports 72 provided in the end of tube 21. The quantity of air drawn into the kiln through these ports may be varied under the control of the operator by suitably adjusting the pressure of the air that is admitted to the riln at various points along the length thereof, as above pointed out.

Substantially no air is admitted to the cooling section through the discharge openings 65 and 66 because the gates 67 close said opening under the action of gravity,.except when the opening is in its discharging position, when the clinker is permitted to drop into the delivery section which itself at that time, is closed to the atmosphere due to the fact that. its discharge opening is then closed by gate 69 under the action of gravity, said opening being arranged diametrically opposite the opening in the kiln as above pointed out. The clinker is thus discharged without admitting substantial quantities of air during said discharge.

The invention may be embodiedin other specific forms without departing from the spirit or essential characteristics, thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of-the' invention being indicated by the appended claims rather thanv by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein;

What .we claim as our invention is: 1. A kilncomprising a tubular body arranged to rotate about an inclined axis composed of a main section and a cooling section connected by a throat section of reduced cllameter, as compared to said sections, said main section adjacent said throat being formed of gradually reduced internal diamcter, means tosu'pply fuel tosaid main section adjacent its reduced diameter and means to supply air to said body.

2. The combination defined in claim 1 in which means to supply the air to the body is arranged adjacent an end thereof whereby the air will't'raverse said cooling section.

3. A kiln comprising atubular body arranged to rotate about an inclined axis to feed the contained material fromend to end thereof, means to supply fuel to said kiln between its ends, means to supply air under pressure to said kiln at a plurality of points to support substantially complete combustion of the fuel, some of said points being so disposed that a substantial quantity of air is admitted adjacent one enclthereof and passesover the material heated to a high temperature at the zone of admission of the fuel. I

4.. The combination defined in claim 3 in which'the kiln body is of gradually reduced internal diameter contiguous with the one or more points of admission of either fuel or air in order that the movement of the material in transit in the kiln is retarded in- 7 said zone.

6. A kiln comprising a closed body arranged to rotate about an inclined axis, fuel .and air chambers carried by said body, conduits conveying the fuel and air from said chambers to points along said body, a stationary casing surrounding said body and mechanism rotating therewith to conduct the fuel and air to said chambers.

7. A kiln comprising a closed elongated cylindrical body arranged to rotate on an inclined axis to cause the materlal to gravltate toward one end of the kiln, a discharge opening in said end of the kiln, an annular chamber surrounding said opening and a discharge opening in said chamber, said opening being arranged substantially diametrically opposite said first named opening and covers to close said opening, said covers being arranged to be automatically closed by gravity in positions other than their discharge positions.

8. A kiln of the rotary type including a plurality of diametrically opposite discharge openings arranged adjacent one end of said kiln and out of alinement with each other, an annular chamber surrounding each of said openings, each annular chamber being provided with an opening substantially in alinement with but diametrically opposite the kiln opening and covers for said kiln and chamber openings, said covers being arranged to automatically gravitationally close said openings except when the kilns contents are discharged through said opening.

-9. That step in the method of burning cement in a rotary kiln substantially closed to the atmosphere and connected to a stack which consists in injecting fluid under pressure into the flow of the products of combustion from said kiln in a direction transverse to said flow whereby the flow into said stack of any solid particles become segregated from the gaseous products of combustion. 10. The method of burning cement which consists in feeding the raw material into an enclosed elongated chamber, causing said material to move end-wise of said chamber at varying rates of movement end-wise thereof, supplying fuel at points where the ma terial moves relatively slow and supplying air to the main section of the kiln under the control of an operator in suflicient quantities to insure substantially complete combustion in said main section of the kiln.

11. A kiln comprising a cylindrical body substantially closed to the atmosphere at all points, arranged to rotate about an inclined axis in which the gradual reduction signatures.

ROBT. W. P. HORN. JACOB H. NISSLEY.

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