US1955914A - Apparatus for producing cement and similar substances - Google Patents

Description

April 24, 1934.

K. E. E. HOLZAPFEL APPARATUS FOR PRODUCING CEMENT AND, SIMILAR SUBSTANCES Filed May 27. 1930 2 Sheets-Sheet l INVENTOR 25ml ATTQRNEY April Z4, 1934- K. E. E. HOLZAPFEL. 1,955,914 I APPARATUS FOR PRODUCING CEMENT AND SIMILAR SUBSTANCES Filed May 27. 1930 2 Sheets-Sheet 2 INVENTOR Patented` Apr. 24,v 1934 `UNITED STATES APPARATUS FOR PRODUCING CEMENT AND SIMILAR SUBSTANCES Karl Emst Eberhardt Holzapfel, Munster, tiermany, assignor to Fried. Krupp Grusonwerk Aktiengesellschaft, Magdeburg-Buckau,

Ger-

many, a corporation of Germany Application May 27, 1930, Serial No. 456,000

In GcrmanyJune 4, 1928 3 claims.

My invention relates to the production of ce-.Hv

ment and is adapted for general use in the manu-I facture of various calcined substances produced by a burning process, and the invention comprehends an improved apparatus or means peculiarly adapted for carrying out said method.

An object of the invention is to combine a rotary kiln of known type with a calcining shaft or pot. According to the invention, the shaft or pot l0 is of relatively small size, for 'the inventor has found that a relatively small column or layerof material makes the best economic use of the exhaust gases coming from the rotary kiln for the pre-heating 'and preburning of the material. Fury (1) Touse a rotary kiln in series with a calcining shaft of relatively small height content,

so that the layer or column of material under calcination will be limited as to thickness or height and be maintained lsubstantially constant. (2) To realize an embodiment in which the hot gases of combustion issuing from the feeding end of the kiln will be' drawn through a movingl layer of material of uniform thickness within the calcining shaft. (3) To make possible an embodiment in which there is auniform or constant mass within the calcining'apparatus, which uniform or constant mass is conducive to steady calcination and oxidation, with a free and rapid escape of the volatile matter and carbonio acid. (4) To enable maintenance at all times of substantial- `ly the same height of material in the calcining apparatus, the improvement in this regard involving the provision o'f an intermediate wall the mass of the material. (5) To realize the inwhich naturally commands the slope and hencetom of the material so that the gases will have to pass through the material and therefore lose much of theirl heat before reaching the grate, thereby affording a protection for the grate.

Other objects and aspects of the invention will appear hereinafter.

Several embodiments of my invention are illustrated herein, the purpose and object of each of which are to illustrate by practical example the application of my method in general, and of selected apparatus through the agency of which to carry the invention into effect in a practical way.

The principles of the invention andthe preferred modes of carrying the same into effect in v a practical way will best be understood by re- '1 0 ferring to the accompanying drawings, forming a material part of this application, and in whch:'

Figure 1 represents a View, in elevation and section, of an apparatus made in accordance with my invention;

Fig. 2 represents a fragmentary vertical sectional view, showing a modied construction in which by reason of the arrangement of the walls in the calcining apparatus a uniform quantity of material is delivered for treatment by a screw and the exhaust gases;

Fig. 3 is a vertical sectional view showing a further modification whereby the gases of combustion are caused to ilow from the top to the bottom of a moving uniform quantity of material within the calcining pot; and

Fig. 4 is a similar view of a still further modication, showing an inclined grate structure for feeding a moving uniform layer of material forI treatment by the exhaust gases. p

' In carrying my invention into effect any suitable or approved furnace may be employed, that shown, by way of example in Fig. 1, comprising a longitudinally inclined rotary shaft kiln 10-and an upright calcining shaft 11, which is of relat tively small height and which feeds directly into the rotary kiln at the feeding or elevated end thereof. 'I'he ,rotary kiln has therein the usual sintering zone or chamber wherein the material under treatment is burned; while the shaft 11, 100 arranged in sries with the kiln, provides a preheating or calcining chamber 11,' wherein the material is heated so as to expell the volatile matter and carbonio acid. Arranged in the rear or discharge end of the rotary kiln is a burner apparatus 12 of any suitable or appropriate type, and by preference of a type adapted to employ fuel consisting of any suitable coal. For supplying the-burning apparatus with fuel, there is a supply line 13 which leads from any suitable source 110 lli) of supply such as a hopper 14; and suitably associated with such supply line 13 is a rotor or blower device 15 vof any suitable or approved type adapted, under pressure, to supply the necessary combustion air along with the fuel fed to the burner 12.

According to an important feature of my invention, the calcining shaft 11 is characterized by the fact that the pre-heating or calcining chamber 11 therein holds a layer or mass of material which is relatively small in 'height or thickness, and further by the fact that the bottom portion 16 of the shaft inclincs downwardly and rearwardly so that the material, as pre-heated or calcined, will be discharged directly into the rotary kiln, and also so that the gases of combustion issuing from the rotary kiln, will pass directly through the discharging pre-heated or calcined material and thence upwardly through the relatively small layer or mass of material undergoing pre-heating or calcination. In the present instance, the discharge. outlet from the calcining chamber is represented as comprising a neck or spout outlet 17 which enters into the interior of the rotary kiln, the bottom of the spout consisting of a downwardly inclined continuation of the bottom 16 for the calciningchamber l1. The front end 18 of the rotary kiln is closed with respect to the delivery neck or spout 17 in order to prevent the entrance of air at this junction point. The closure means is represented as consisting of annular bushing or packing portions y19 between which the front end 18 has turning fit.

Connected with the upper portion of the calcining shaft 11 is an exhaust gas line 20, in which is incorporated a suitable fan or blower device 21 for rapidly effecting the discharge of the gases. A downwardly inclined conveyor device 22 is operatively arranged upon the downwardly inclined bottom 16, such device being arranged to receive thereon material as it settles downwardly in the calcining chamber 11' and to convey the material downwardly over the bottom to a point adjacent the rear end o the spout 17, where the material enters the rotary kiln. At the rear end of the conveyor, there is arranged within the delivery spout 17, a stirring or discharging apparatus preferably consisting of a plurality of curved vanes 23, which are carried by the rotary kiln. By the operation of the stirring or discharging vanes 23 in conjunction with the operation of the conveyor 22, the material is kept constantly traveling from the calcining chamber 11 into the rotary kiln. An advantage of this arrangement is that the material is prevented from Isticking and at the same time it is kept loose and in motion whereby to enable rapid travel of the combustion gases therethrough. Attention is here called especially to the fact that under the instant arrangement, the rotary kiln is placed in series with a calcining shaft, the height of which is-limited so that the 4 layer or mass of material therein will be of small height or thickness. Under this arrangement, Jhere is no pronounced fluctuation in the layer or mass of material undergoing the calcining process. Uniform calcination is, therefore, obtained, and in view of the conveyingand stirring devices associated with the outlet for the calcining shaft, there is no sticking or accumulation of the material, the calcining operation is hastened and the output is, therefore, increased.

The raw material may be introduced into they calcining shaft by any suitable or approvedl 'means, that herein shown consisting of a hopper 24 and a feed screw 24a which conveys the material to the mixing screw 24h where the material is moistened by water issuing from a water pipe 24e. By mixing it with water, the material is formed in small bodies or crumbs. The material falls from the mixing screw 24h into a chute 25 having a pair of gate valves 25a which open downwardly so as to feed the material into the calcining shaft and -in a manner to avoid in so far as possible the admission of air into the calcining shaft. Associated with each of the gate valves 25a is an arm 25h weighted at 25o, whereby normally to urge the valve to closed position. In order to maintain a constantly uniform layer of material within the calcining shaft, a downwardly and outwardly inclined overflow pipe or channel 26a is provided, and this pipe is equipped with weight operated gate valves 26e similar to the gate valves 25a. IThe material passing through the overflow pipe or channel 26a is taken up by a conveyor 26d for redelivery through the channel 26e into the chute 25. At the rear end of the rotary kiln, I may provide any suitable rotary cooling drum 26 for receiving the clinkers as they fall from the rear or discharge end of the rotary kiln.

In the exemplication shown in Fig. 2, 27 designates the rotary kiln and the upright calcining container or pot 28, which feeds into the rotary kiln through the spout 29, is divided intotwo parts 30 and 3l by a vertical wall 32. The material to be pre-heated or calcined enters the top of the part 30 through an air-tight feeding supply 33, equipped with a pair of weighted gate valves 33a similar to those hereinbefore described. The lower end of the part 30 is open so that the material will falltherefrom to produce or tend to produce upon the bottom 34 a cone-shaped mass or layer of material 35, through which the hot gases of combustion must pass in order to reach the part 31, with the top of which is connected a gas outlet line 36. For drawing out the gases, a suction fan 36a is incorporated in the outlet line 36. Arranged above the bottom 34 is a screw 37 for discharging the material through the spout 29 into the rotary kiln. By this arrangement, the same thickness of material is maintained at all times in the calcining pot, since the coneshaped mass naturally passing to the screw 37 upon the bottom 34 tends always to constitute a determinate quantity. If desired, the wall 32 may be made vertically adjustable in order to increase or decrease the quantity of the cone-shaped mass tending to assemble upon the bottom 34. As represented in the drawings, `the discharge screw 37 is shown as provided in advance of the screw threads with a plurality of pins 37a adapted to stir the discharging material and whirl the same into a loose condition. -The drying of the ma;- terial, the passage of the exhaust gases therethrough and the delivery of the material into the kiln are thus facilitated. Moreover, by the whirling action, the exhaust gases come into contact with greatly increased surfaces of the material, a condition which is conducive to a rapid exchange of heat.

In Figs. 3 and 4, I have disclosed arrangements whereby the hot gases of combustion are guided downwardly from the top to the bottom of layers of material within the calcining pot. In the specific instance illustrated in Fig. 3, the combustion gases, in passing through the pot 38, are required to descend through the layer of material main.- tained constant and uniform by the wall or baille 39. The material `is supplied through the inlet 40 anda plunger device 41, arranged to operate with an outlet channel 54 for the gases.

across the downwardly inclined grate 42, serves as the instrumentality for 'feeding the material into the rotary kiln 43, the plunger device operating in a path to push the material under the wall 39 for delivery into the kiln. After passing downwardly through the layer of material, the gases leave through the downwardly inclined grate 42 and escape through the smoke outlet 44.

In the particular form of construction illustrated in Fig. 4, the material is supplied bya feeding screw 45 into the chute 46 for delivery onto the elevated end of a grate 47 made in the form of a descending series of steps, as shown, in order that a layer of material 48 will move downwardly from the front wall 49 of the calcining pot to the rear wall 50 thereof. The hot gases of combustion leave the .feeding end of the rotary kiln 5l and enter the pre-heating chamber 52, thence being drawn or sucked downwardly through the relatively thin layer of moving material 48 and through the grate 47 into the chamber 53 therebelow. Said chamber 53 is in communication At the rear end of the calcining pot, the material feeds into a pocket 55 in which a screw conveyer 55a operates totransport continuously a certain amount of material from the layer 48 to the elevator or conveyer 56, which in turn carries the material upwardly for delivery into a downwardly and forwardly inclined chute 57 for delivery into the rotary kiln 51. The pocket 55 always holds a definite quantity of material which ent-ers from the moving layer 48 through a prescribed open 55h, but the `quantity of material passing through` the pocket 55 naturallyV depends upon the speed of the screw 55a. These parts are proportioned and regulated so that always'a constantly uniform quantity of material will be conveyed by the elevator 56 to the chute 57 for delivery into the kiln. In this construction, the material within the calcining pot, as it travels slowlyl down the descending grate 47, is spread into a relatively thin layer as shown, so that the surfaces of the moving material are very considerably exposedl to the action of the hot gases of combustion. In this form of construction, it is to be understood that the chute or supply pipe 45 will constantly be kept full of material so as to exclude the outside atmosphere without the use of gate valves such as illustrated and described in connection with Figs, 1 and 2.

In all courses the material is preferably fed into the calcining potfin such condition that it will greatly facilitate the passing therethrough of the exhaust gases. For this purpose the material may be formed into bricks or into any suitable shape. Also, if desired, the material may be pre-heated in any customary or approved mannerand in granulated form, either a drum or a mixing screw of appropriately approved type being used for handling or mixing the granulated material in this condition.

While I have described my invention as comlustrated it with the aid of certain selected forms for carrying it into eifect, it will be understood that the invention may be variously embodied. It has been sought herein to illustrate only such embodiments as will suice to exhibit the character of the invention. Reservation is, therefore, made to the right and privilege of changing the form of detail set forth or otherwise altering the arrangement of the parts without departing from he spirit or scope of the invention or the scope of the appended claims.

I claim:-

1. In combination, a rotory kiln, a substantially horizontal feed shaft having one end in communication with the kiln for discharging material thereinto and receiving gas therefrom, separate compartments associated with the opposite end of the feed shaft, one for passing material downwardly into the feed shaft and the' other for receiving gas flowing through the feed shaft and material fed into the same, means for withdrawthe feed shaft for' moving received material therethrough and into the kiln, and a material stirring device associated with said screw adjacent the discharge end of the feed shaft.

2. In a kiln feeding device, a horizontally disposed feed shaft having an outlet end adapted to be associated with a kiln to discharge' material thereinto and toreceive the combustion gases therefrom, mechanical means operating in the shaft for feeding material to the outlet end for discharge from the latter, an inlet feed for the shaft, connected thereto from a lateral direction for supplying material to .the mechanical means and adapted to supply material to maintain a section of the shaft substantially filled crosssectionally with a mass of material and during the operation of the mechanical means, and means for maintaining a continuous flow of the combustion gases reversely through the material being fed and the mass cross-sectionally filling the section of the shaft.

3. In a feeding device for kilns adapted to receive the hot' gases from the kiln for conditioning the material being fed, a feed shaft adapted to be disposed horizontally and having an outlet end through which to discharge material and receive the gases, a suction chamber associated with the remote end of the shaft, means for drawing the gases from the outlet end to said suction chamber, an inlet feed connected with the shaft from a lateral direction at a point between the outlet end and suction chamber, operating means in the shaft for feeding material from the inlet feed to the outlet end for discharge from the latter and through the gases moving to the suction chamber, said inlet feed being adapted to supply material to maintain a section of the shaft substantially filled cross-sectionally with a mass of material through which the gases are required' to pass on their way to the suction chamber.

KARL ERNST EBERHARDT HOLZAPFEL.

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