US1199856A - Limekiln. - Google Patents

Description

A. ZIMMERMAN.

LIMEKILN.

-, APPLICATION FILED FEB. 25. 1915. 1,199,856, I Patented Oct. 3,1916.

5 SHEETS SHEET1.

A. ZIMMERMAN.

LlMEKILN.

APPLICATION FILED FEB. 25. 1915.

1,199,856. Patent-ed oat-3,1916.

5 SHEETS-SHEET 2- wi f nmv/az I? 3 nwwho a A. ZIIVIMERMAN.

LIMEKILN.

APPLICATION FILED FEB. 25. l9l5.

1,199,856. Patented Oct. 3 6.

v 5SHEETS-SHEE A. ZIMMERMAN.

LIMEKILN.

APPLICATION FILED FEB. 25. 1915;

1,199,856.. I Patented 00 1916.

5 SHEETS- a ALBERT ZIMMERMAN, F YORK, PENNSYLVANIA, ASSIGNOR TO LOWELL M. PALMER,

or BROOKLYN, new YORK.

LIMEKILN.

To all them it may concem Be it known that I, ALBERT ZIMMERMAN,

I a citizen of the'United States, residing. at

York, in the county of York and State of- Pennsylvania," have invented certain. new and usefullmprovements in- Limekilns, of which the following is a full, clear, and

exact description.

1 .This invention relates to kilns forburning lime and like calcareous material, and is principally adapted for use with kilns, using a producer or other gas as the source of fuel supply, the kiln consisting of a vertical stack or shaft into which the material is fed at the top and discharged at'the bottom, there be- ,ing an intermediate zone within the stack in which the lime is calcined during its descent.

Other objects of the invention are to pro-- vide for the regulation of the temperature of combustion and to control the height of the flame within the stack; to protect the 'jects, which will be apparent from the dewalls of the stack from the direct action of the flames, to prevent explosions in the lower part of the kiln and to provide means for determining when the proper amount of air is being admitted to the stack to mix with the gas to obtain a complete combustion thereof.

In accordance with these and other obtailed description hereinafter to follow, my

invention consists broadly in introducing the main volume of air which supports combus tion into the stack at a point some distance below the point at which the gas enters it, but also some distance above the bottom of the stack. Some air, however, may be permitted to enter the stack through an opening in the bottom thereof and to circulate upwardly through the mass'of material until it reaches the gas inlets. By providing the main air inlets at the pointdescribed, a sufficient quantity of air may be readily 1n- 'tl'Odl lCed into the stack under the suction caused by the natural draft within the stackor under low pressure to effect the complete combustion of the gas. airpasses upwardly along the walls of the stack until it reaches the gas inlets and thus Specification of Letters Patent. a lication filed February 25, 1915. Serial No. 10,388.

A portion of the Patented Get. 3, 1916.

all portions of the burning zone of the stack,

resulting in a uniformly burned product and hence one of a superior quality. This uniformity of combustion is promoted where the air, and also the gas, are introduced into the stack through a plurality of inlets arranged around and leading into the interrior of the stack at spaced intervals, as is contemplated in my preferred construction.

Since the gas diffuses rapidly and is ignited immediately upon its entrance into the chamber, the height of the flame within the stack and the temperature of the same may be controlled by the quantity or volume of air which is introduced through the main air inlets, which volume may be controlled in any desired manner. 1

In the accompanying drawings: Figure 1 shows a vertical section of a double kiln constructed in accordance with the principles of'my invention; Fig. 2 is a similar section taken at right angles to Fig. 1; F 3 is a horizontal transverse section taken on the line 33 of Fig. 2; Fig. 4. is a horizontal transverse section taken on the line 4-4 of Fig. 2.;Fig. 5 is a horizontal transverse section taken on the line 5-5 of Fig. 2; Fig. 6 is a. horizontal. transverse section taken on the line 6-6 of F ig.' 1; Fig. 7 -is a central verticalsection of a single kiln; Fig. 8 is a similar section taken at right angles to Fig.

'7 'and Fig. 9 is a horizontal transverse secinner periphery of the shaft may be provided with a suitable lining of refractory brick or other-material, and forms a vertical chamber which maybe regarded as divided into threezones, the upper one comprising the feeding zone 3, an intermediate zone 4, inwhieh the material is burned, and

I 25 separate discharging passages, the lower ends of which are circular or square in cross a discharge zone through which the material is discharged. The burningzone in the double type of kiln is traversed by a vertical partition or bridge 6, the upper end of which'is wedge;shaped and is protected by meansof an iron cap 7 so that it will notbe worn. by the lime or other calcareous v the stack.

material as the same passes downwardly from the feeding into the burning zone of This bridge or partition therefore divides the burning zone of the stack into two separate burning chambersS and 9, respectively, which are preferably ellipticallyshaped in cross Section (see Figs. 3, tand 6) 'thatthere will be no sharp corners along which the air might find a ready passage to the higher portion of the stack and 'thus produce eddy-currents within the burning zone. is formed by a continuation of these chamhers and is divided adjacent its bottom by a second vertical transverse bridge or partition wall 10 at right angles to the partition 6, which, together with the partition 6, di-

vides this portion of the stack into four character, its movement down through the shaft when the kiln is drawn, to what extent the draw is to be made, and prevent masses of material becoming fluxed and clogging the stack. While the kiln is in operation, these poke holes are vcovered by doors, which are practically airtight, so that no appreciable amount of air is admitted through them into the stack. Extending through the bridge 6, there may be provided a plurality of passages 16, through which the outside air may circulate to cool "the bridge.

The producer or other gas is introduced into the interior of the stack at the bottom ,of the burning zone. In its preferred embodlment, my invention contemplates ad-,

mitting the gas at a plurality of points spaced around the. walls of the burning chambers 8 and 9. This is accomplished by the OOIlSiZI'llClllOIl' which is most clearly shown in Fig.- 3, wherein the gas inlets are shown in full, there being three spaced gas inlets, 17,18 and 19 leading into each of the burning chambers through the outer side wall thereof while extending into each. end of these cli the po The discharging zone of the stack ambers are the gas inlets 20 and 21, I I respectively. In orderto supply the gas to tlon of the chambers adjacent the inner or partition wall 6, gas inlet s or ducts 22, are also provided which pass longltudinally through the bridge 6, where they communicate with transverse ducts 23. Gas is supplied to. these. inlets by means of pipes 24 connected to any suitable source which communicates with a distributing pipe 25, extending around the stack to which the various gas inlets are connected by valve controlled branch pipes 26. The pipes 24 are connected to the supply of gas from the producer or other source under pressure, to force the-gas into the'stack under low pressure.

Referring now to the manner in which air so is supplied to the burning zone of the stack to support combustiom-a portion of the air enters through theopen discharging pipes 11, which air will circulateup through the mass of material within the discharging hoppers in the discharge zone 5, but it has been found that suflicient air cannot be admitted in this manner to properly support combustion if the air is permitted to enter under natural draft. as only a small quantity of it will force its way upthrough the dense mass of material within the discharge hoppers. Whether the air enters under natural draft or pressure, if the discharge chambers are circular or substantially circular in cross section, as is the usual construction, the air will have its greatest flow through the center of the mass of material so that upon reaching the level of the gas inlets, it will not v be spread evenly throughout the entire mass. The lime in the center of the burning zones of the stack will therefore be subjected to the hottest flames and gases of combustion, the result of which will be an unevenly burned product. In the construction disclosed, the air which. enters through the bottom of the stack, is therefore not de- "pended upon to supply the necessary quantity to support combustion, but this is taken care of by introducing the air into the discharge zones of the kiln at a point below the gas inlets and in the best practical constructions of the kiln, the air should be admitted at a distance varying from 2 to 8 ft. below the gas inlets to obtain the most beneficial 7 results. Instead of permitting the, air to enter the stack through a single air inlet, a plurality of such inlets 26 (see Fig. 5), are preferably provided. The number of air inlets is preferably greater'than the number of gas inlets, and as is'clear from Fig. 30f the drawing, they are arranged in staggered relation with the gas inlets so that there will be no tendency for the air to form a current passing directly, upon its entrance, into the stack up to one of the gas inlets where it will be ignited, but -will rather, due to the location of air inlets, spread out to form a film covering the walls of the chamber and also circulate freely messes the kiln.

l In order to maintain a constant draft or 7 suction within the shaft, which would vary with atmospheric conditions, it has been found advisableto closethe top of the stack 10 by,a..cover 28 and to withdraw the gases and products of combustion from the stack by ineensmf a-suction blower 29, which is connected to the stack by means of the pipe 30, the gases being exhausted from the blower into the atmosphere through a. pipe 31. In

this manner, the suction or draft within the kiln may be maintained atany desired pressure which will, in the most practical operation of the kiln, approximate the reduced pressure caused by a natural draft.

Referring now to the modified construction shown in- Figs. 7 8 and 9, the construc-' tion is in general similar to that disclosed except that only one burning chamber 32 is provided which, as is shown in Fig. 9, is

elliptical in'cross section. The shaft at the bottom of the burning zone. is in' the same manner provided with gas inlets 83 which lead directly into this chamber at the bottom 80 of the burning zone, while there is provided for each gas inlet one or more air inlets 34 positioned below the gas inlets in the same manner as where av double kiln is used, the

gas and air inlets being staggered as before described, and so arranged that they lead into the burning and discharge chambers at spaced intervals in their walls. It is, of course, understood that this form of kiln is also provided with poke holes and the air inlets are controlled by dampers;

The operation of both forms of kiln is identical and will now be described.

Assuming that the stack is filled with the desired material, such as lime, and the suction blower has been started to create a draft therethrough and the gas is being permitted to enter through inlets 17, 18, etc., or 33 at the bottom of the burning zone, a small quantity of air insuliicientto support compl'ete combustion will, as described, force its .way up through the mass of materialin the dlscharge zone of the stack, that is, in the double kiln through the four discharge hoppers which lead to the two chambers 8 and 5b .9, and in the single kiln to the chamber 32 through the two discharge hoppers. Due to the fact that the upper portion of the discharge zone and the burning zone are elliptical in cross section, the greater portion of this air which finds its way in through the bottom of the stack will circulate upwardly in a greater volume through the central area of the mass of material within the same. The main volumeof air is, however, admit ted through theair inlets 26" or Beat a point somewhat below the gas-inlets, This volume of air is, as is the gas, led into the stack at spaced intervals in thawalls of the discharge chambers so that the v volum e of air which is admitted to all ortions oi the chamber are approximately t e same. Since the walls separating the air and gas inlets are vertically disposed and are intentionally so constructed, a portion of the volume of air which enters through the air inlets Wlll tend to pass directly up toward the gas inlets in contact with the face of the wall and Will in this manner serve to protect and to cool the lining ,of the shaft andiprotect it from destruction by the hot mass of material within the discharge zone of the stack. Another portion of the air, however, since any desired quantity or volume of air may be permitted to enter the stack at this point by vproviding air inlets of suflicient area, circulatesfreely'and spreads evenly through the the discharge zones of the stack so-that when it reaches the level of the gas inlets it will have permeated the entire mass of material. The gas entering through these inlets will, therefore, rapidly ditfusethrough the volume of air thus disposed, and as its ignition takes place immediately upon the entrance of the gas into the stack at the bottom of the burning zone, the combustion will take placeuniformly throughout the material.

It is desirable that the air enter the shaft under the suction caused by a natural draft within the stack, under which conditions the air will circulate up through the mass of material, as described, and there will be no tendency for it to force its way throughthe material to form air currents and take circuitous paths through the mass of material, the result of which, in each instance, would be the unequal burning of the massof material within the stack.

Another advantage which is derived from interstices of the mass of material Within volume of airmay be controlled by means of dampers, and in this manner the height of the flame Within the stack may be regulated to any desired degree, since the gas spreads evenly throughout themass of material and as the draft is uniform, the height of the flame will depend upon the volume of air whichis permitted to enter the stack, since it is through this Volume that the gas is rapidly diliused'to form the flames and hot, gas ofcombustion after it has been ignited. It will also be seen that the temperature of the hot gases of combustion may be controlled, for if a certain quantity of air sufiicient to produce the complete combustion of all of the gas entering through the gas inlets a greater volume of air may be admitted through the openings which may sex-veto dilute, and therefore lower the tem- &

the kiln that the draft is'insuflicient to sup ply the necessary quantity of air for complete combustion of the gas entering the kiln shaft and carry oil the products of combustion. The air inlets will also serve to prevent-explosions in the lower portion of the stack, which are frequently occasioned by imperfect draft'or the improper A still further feature ofthe i diffusion of the air and gas. I

vention resides'in the combination between a stack having an opening in its bottom through which the air enters'and a plurality of air and gas inlets disposed in the manner described, and which lead into a stack at spaced intervals in its inner face. This construction positively insures an even distribution of the air throughout the mass of material before it reaches the level of the gas inlets, since as described, the air entering- ,through the bottom tends to take a central path through the mass of material, while that which enters through the various air inlets Will occupy the interstices between the remaining portions of the mass of material adjacent the walls of the stack and the commingli-ng of the air entering from both sources cannot but give an even distribution of the air throughout the cross sectional area of the burning zone.

While in the preferred form of my inven' tion, Ihave shown and described the air admitted through the main air inlets as entering the stack under the suction caused by a natural draft within the stack, yet it will" be apparent that the air which enters in this manner may be introduced into the stack under low pressure, and a substantially balanced draft obtained withinthe stack. A This might be accomplished by providing a distributing pipe ring surrounding the stack and having a plurality of branches passing through the walls of the stack through which the air could beforced into the mass of material within the stack at a point approximately on a level with the location of the air inlets disclosed, but if this construction is used some of the advantages resulting from the use of the air inlets, as disclosed, will be lacking or lessened, some of which are: there is no means by which the character of the draft within the stack may be in-. dicated or explosions prevented in the lower part of the stack; and there will also be a stronger tendency for the air when it enters. under pressure 1n this manner to force itsncense way toward the central portion-of the stack rather than to spread evenly throughout the mass ofmaterial adjacent the walls of the discharge and burning zones. While'I do not regard this means of introducin the air as efficient as the one described, yet do not wish to be limited to the specific construction shown, but only by the scope of the claims appended hereto.

I claim: 1. A kiln for burning lime and with the material to be burned and divided .into a feed, combustion and discharge zone,-

said stack having a plurality of gas inlets therein entering said stack at a plurality of points around the entire peripheral surface of the inner wall and positioned on a level with the bottom of the burning zone, and a plurality of air inlets entering the discharge zone of the stack at spaced intervals around the entire peripheral surface of its inner face points spaced around the entire peripheral surface of the inner wall and positioned on a level with the bottom of the burning zone, and a plurality of air inlets entering the discharge zone of the stack at spaced intervals around thefentire-peripheral surface .of its inner face and spaced from and beneath said gas inlets, said air inlets being open to the atmosphere at their outer ends.

3. A kiln for burning lime and like material, comprising a stack adapted to be filled with the material and divided into a feed, combustion and discharge zone, said stack being divided in its combustion and discharge zones into a plurality of chambers, means for introducing gas into said chamhers at a plurality of points spaced around the entire peripheral [surface of the walls thereof, and means for introducing the main volume ofair into said chambers at a plu- 'rali'ty of pointsspaced around the entire peripheral surface of the walls thereof at points below said gas inlets.

4. A kiln for burning lime and like material, comprising a stack adapted to be filled with the material and divided into a feed,

combustion and discharge zone, said stack being divided in its combustion and dis charge zones into a plurality of chambers, means for introducing gas into said chambers at a plurality of points'spaced around the entire peripheral surface of the walls thereof, and means for introducing the main volume of-air into said chambers at a plurality of points spaced around the entire pee: M .ripheral surface of the walls'at'pointsbelow 139 like material, comprising a stack adapted to be filled said gas inlets and arranged out of vertical alinement therewith.

5. A kiln for burning lime and like calcareous material, comprising a stack adapted to be filled with the material to be burned and divided into a feed, combustion and discharge zone, said discharge zone having an opening in its bottom through which air may enter the stack, said stack having a plurality of gas inlets entering said chamber at spaced intervals inits inner face and positioned on a level with the bottom of the burning zone, and a plurality of air inlets in the walls of said stack entering the discharge zone of the stack at spaced intervals in its inner face spaced at a distance from and beneath said gas inlets, said air inlets being open to the atmosphere at their outer ends.

6. A kiln for burning lime and like calcareous material, comprising a stack adapted to be filled with the material to be burned and divided into a feed, combustion and discharge zone, said stack having a plurality of gas inlets entering said chamber at a plurality of points spaced around the inner peripheral surface of the inner face thereof andpositioned on a level with the bottom of the burning zone, a plurality of air inlets entering the discharge zone of the stack at a plurality of points spaced around the inner peripheral surface of the inner face thereof and spaced from and beneath said gas'inlets, and means for producing a con I stant suction within said stack.'

7. A kiln for burning lime and like calcareous material, comprising. a stack adapted to be filled with the material to be burned and divided into a feed, combustion and discharge zone, said sta'ck having a plurality of gas inlets entering said chamber at a'plurality of" points spaced around the inner peripheral surface of the inner face thereof and positioned on a level with the bottom of the-burning zone, and a plurality of air inlets, greater in number than the number of gas inlets, entering the discharge zone of the stack at a plurality of points spaced around the inner peripheral surface of the inner face thereof and spaced from and beneath said gas inlets. y

In witness whereof I- subscribe my signature in the presence of two witnesses. ALBERT ZIMMERMAN. Witnesses:

WALDO M. CHAPIN, JOSEPH A. BUCKLEY.

Images