US2891321A - Apparatus for cooling cement clinkers - Google Patents

Description

H. HABEL APPARATUS FOR COOLING CEMENT CLINKERS June 23, 19 59 6 Sheets-Sheet 1 Filed July 5, 1957 INVENTOR flex; A25 8 June 23, 1959 V H. HABEL 2,891,321

APPARATUS FORYCOOLING CEMENT CLINKERS Filed July 5, 1957 6 Sheets-Sheet 2 June 23, 1959 H. HABEL 2,891,321

APPARATUS FOR COOLING CEMENTCLINKERS Filed July 5. 1957 6 Sheets-Sheet a INVENTOR //e/az A4966! H. HABEL APPARATUS FOR COOLING CEMENT CLINKEIRS June 23, 1959 6 Sheets-Sheet 4 Filed July 5, 19 57 INVENTOR A e/az #06 e/ June 23, 1959 H. HABEL 2,891,321 APPARATUS FOR COOLING CEMENT cuuxsas Filed-July 5. 1957 e Sheets-Sheet 5 June 23, 1959 H. HABEL APPARATUS FOR COOLING CEMENT CLINKERS 6 Sheets-Sheet 6 Fi led July 5. 1957 j I r LiiNl rl i rP. \w m INVENTOR A eg'az 5 46 e/ United States Patent 2,891,321 APPARATUS FOR COOLING CENIENT CLINKERS Heinz Habel, Erfurt, Germany, assignor to VEB Zementanlagenbau Dessau, Dessau, Germany This invention relates to burnt or calcined material, such as for example cement clinker, obtained in kilns or the like; and more particularly to a method and apparatus for cooling such material.

While the invention will be described in relation to cement clinker, it should be understood that the method and apparatus ofthis invention are applicable to the cooling of other burnt, calcined or fused materials which are also in grain form.

For the purpose of cooling cement clinker, cooling drums and inclined grate or horizontal coolers have hitherto been employed. With a view to successfully carrying out the cooling of the clinker, the following five requirements should be achieved, 'which requirements are either not achieved at all or only partially afiorded by known cooling devices. l

. These requirements are the following: i

. (1) The cooler should be uniformly charged with hot clinker material in order to obtain a uniform layer thickness.

(2) The amount of clinker falling through the grates should be reduced as much as possible so as to eliminate the necessity for providing conveying arrangements for clinker removal below the grates. Further, such reduction in the amount of clinker material falling through the grates reduces wear on the elements arranged below the grates and thus protects such elements, whereby work stoppages are reduced and production is consequently increased. i Q

(3) Efiicient distribution and conducting of the cooling air as Well as eflicient contact of the air with the clinker material should be provided.

(4) Deflecting and conducting away of the combustion air, with respect to the quantity and temperature of such combustion air, should be efiiciently carried out for the purpose of obtaininga uniform high temperature.

(5) Deflection of a quantity of air of a temperature suitable to dry the fuel which is required for the burning or firing should be achieved.

It is an object of this invention to provide a method and apparatus for cooling clinker material which fulfills all of the aforementioned requirements.

The cooling apparatus to the invention comprises a rotary grate. The rotary grate may comprise a plurality of horizontally-rotatable, superimposed annular ring-like members provided with grate plates or segments. The several rings may be rotated separately at different speeds or they may be stationarily arranged. The several rings should be mounted eccentrically relative to each other.

A confining or enclosing wall is arranged outside the outermost ring, which wall is spirally-shaped. The hot clinker material is supplied to the rotary grate cooler at that area of the cooler which corresponds to the junction of the largest and smallest radius of the spiral.

The speed of revolution of the outermost ring is adjusted in accordance. with the output of the rotary kiln. Due to the spiral shape of the enclosing wall, the clinker, upon rotation of the outermost ring, is urged toward the center of the cooler. This feeding movement of the clinker takes place slowly and uniformly throughout the cooler.

The grate plates or segments to which the clinker falls may be fitted with horizontally-extending nozzles, or the grate covering element may be provided with horizontally-directed slots. In this manner, the falling of the clinker material through the grate elements is prevented. The grate elements or plates are arranged in a step-wise manner, and each ring is arranged eccentrically to the one thereabove. All of the grate rings may be of the same construction. With the exception of the innermost ring, all of the rings should be adjustable with regard to their speed of revolution. The innermost ring is also eccentrically arranged relative to the preceding ring, but being however stationarily mounted and surrounding a vertical delivery duct. The delivery duct terminates at its lower end in a rotatable disc arranged at some distance from the lower end of the duct proper. Upon rotation of this disc the clinker which has collected on the disc is deflected or scraped off of the disc by a scraping device. Theamount of clinker to be scraped from the disc may be adjusted by altering the number of disc revolutions or by adjusting the position of the scraping device. The amount of clinker to be removed is adjusted in such a manner that the entry of undesired air through the delivery duct is prevented.

It is advantageous to effect a separation of the heated air to an. extent determined by its temperature, so that at any time, not only the quantities of the air, but also the temperatures can be controlled and thus adjusted. The separation of the hot air quantities is efiected in such a manner that the relatively large amounts of air of lower temperature which are required for the complete cooling of the clinker cannot by themselves mix with the cooling air of higher temperature.

Other objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawings forming a part of this-specification, and in which:

Fig. 1 is a vertical section, shown somewhat schematically, of a rotary kiln operatively associated with a first embodiment of a rotary grate cooler made in accordance withthe invention, the figure at the same time schematically indicating the cooling process;

Fig. 2 is a perspective view of the inclined chute of Fig. 1 along which the burnt material falls into the grate cooler;

Fig. 3 is a top plan view of cooler shown in Fig. 1;

Fig. 4 is anenlarged section through a portion of the cooler grating and showing the detail thereof;

Fig. 5 is a perspective view of the grating plates of Fig. 4;

Fig. 6 is a section taken along lines 6-6 of Fig. 1;

Figs. 7, 8 and 9 show details of the driving arrangement for the rotation of the grate rings;

Fig. 10 is a schematic representation of the grate rings without the grating surfaces and the driving arrangement;

Fig. 11 is a vertical section through a second embodiment of a rotary grate cooler made in accordance with the invention and comprising a second cooling stage for obtaining a high cooling effect;

Fig. 12 is a vertical section through a third embodiment of a rotary grate cooler made in accordance with the inthe grating surface of the vention, which cooler includes a step-shaped grating ar-.

Fig. 1, reference numeral 1 indicates a rotary kiln which i is operated by a coal dust firing, as schematically indicated by reference numeral 2.. The burnt material 3 falls along an inclined chute 4 into the rotary grate cooler. The chute 4 is provided with nozzle-like openings 5 for the --passage of air as perspectively shown in Fig. 2. Cooling air introduced through the nozzles 5 contacts and consequently precools the hot clinker material during its travel along the chute 4. This coolingair, furthermore cools the chute proper, thus prolonging the life thereof. a

l The cooling air is supplied to the nozzles through an air duct 11a (Figs. 1 and 2) by means of a connecting line 11b. A throttle valve 110 is built into the line 11b foradjustin'g the air flow. The cooler surface onto which the clinker material 3 falls, and by which the latter is supported, comprises annular members or grate rings 7, 8 and 9 arranged eceentrically relative to each other, as shown in Fig. 3. The rings 7, 8 and 9 form jointly with the clinker material thereon a hollow cone. The ring 7 is arranged below a spiral-shaped confining Wall 10, which Wallis provided with cooling air nozzles ll which in turn communicate with the air duct 11a. The spiral shape of the wall causes a reduction of the inner diameter of the cooling space cross section as compared to a circular cross section. Upon rotation of ring 7, which rotates beneath the wall 10, the clinker material-due to the decrease of the cross section of wall 10-is positively pushedonto the grate ring 8. The beginning of the spiral (largest diameter) and the end of the spiral (smallest diameter) may either be directly connected with each other the shortest way as shown by the dash-dotted line in Fig. 3, or the transition may be eifected gradually. Due to rotation of the grate rings 7, 8, and 9, the clinker material 3 is continuously conveyed toward the center of the cooling arrangement. Below the ring 9 extends a shaft 12 which terminates at its bottom end in a rotatable disc 13. For the purpose of permitting the pas sage of air through the shaft 12, the latter is provided with openings 14. The cooled clinker material 3 is directed by a stripper '15 to a receiving funnel 16, through which the cooled clinker material 3 falls onto a conveying arrangement 17 for transportation away from the plant. The rotatable disc 13 may, for example, be drivenby a bevel gear drive indicated at 13a. The number of revolutions of the disc 13 may be adjustable, or the position of the stripper 15 may be made variable, whereby the amount of clinker material to be fed to the funnel 16 can be adjusted.

'The'a'ir escaping from the spaces or zones 19 and 20 may be recovered and used for any desired purpose, or may be conducted to the chimney.

The quantities of air which have to be supplied to the cooler through the nozzle 5, 11 and '14, and the slots or passages of the grate ring ,(to be presently described), are produced by blowers or the like. The lines through which-this air 'is conducted to the various inlets have been shown in Fig. l.

A cylindrical separating wall '28, extending between the air spaces or zones '18 and 20 and 19 and 20, respectively, extends downwardly to the surface of the clinker material 3. In this manner, travel of the cooling air above the clinker layer from one zone to the other, is prevented. An air-cooled ring 29 forms the lower end portion of this wall 28'. The cooling air is conducted from this ring 29'through nozzles 2911 into the zone 20. The required cooling air is branched off from the same duct 211a from which air flows to and through the nozzles 11. The connecting line is'formed by pipes 11d into which throttle valves 11c are built in order to control the air flow. With a view to controlling the temperatures of the cooling air from the zones 18 and 19, these zones communicate with the zone 20 through connecting channels. The cross-sectional area of these channels are adjustable by regulating flaps, as for example, indicated at 30.

Fig. 3 is a top plan view of the grating surface of a rotary grate cooler, for example, the cooler shown in Fig. 1, the various elements built into the cooling space, however, being omitted and the figure being a horizontal section through the air duct 11a and the nozzles 11. The grate rings can be recognized at 7, 8 and 9, while the cooling air nozzles 11 are schematically shown as being arranged in the spiral-shaped confining wall 10 which is provided above the outermost ring 7. Further, this fig ure makes it clear thatthe grate rings are covered by segments or plate-s serving as grate elements.

A cross sectional view of these segments or plates is presented in Fig. 4. A perspective view further illustrating the plates is given in Fig; 5. In order to prevent the clinker material from falling through the grate elements, which may cause the soiling and increased wear of the elements and the supports arranged below the grate elements, the cooling air outlets 22 are provided only on the vertical walls of the grate plates 21. Each grate plate 21 includes a top plate 21a supported by spaced ribs 21b. Between the supporting ribs 2112 are formed air passages, the path of the cooling air being indicated by the arrows in Figs. 4 and 5. A part of the lower extremities of ribs 2117 are joined by a cross plate 21e. Each grate plate 21 is sealed against the plates of the adjacent ring by a movable sealing piece 23. The grate plates 21 are detachably and thus interchangeably secured to circular carriers 24.

The plates 21 are secured against displacement transverse to the circular carriers 24 by the cooling ribs provided'with abutment pieces 21d. In order to interchange the plates, the latter arelifted to an extent corresponding to the height of the abutments -by pulling towards the center of the cooler. The mounting of new plates is effected in reverse manner. The circular carriers 24 may be driven, for example, by gear rims 25. The carriers 24 ride on rollers 26 which bear on roller tracks 27. The rollers 26 are arranged equally spaced along the track 27. The rollers are slightly conical in shape and are held in proper alignment by a spacing .ring (not shown), as is common practice in ball or roller bearings.

The gear rims 25 are preferably driven by means of driving pawls. Figs. 7, 8 and 9 illustrate a preferred embodiment of such a pawl driving arrangement. By means of a reciprocating connecting or push rod 40 parallelly mounted drive shafts 42 are made to rotate in oscillating manner through a lever and rod system 41a, 41b and 410. The shafts 42 are mounted in bearings 43 and move in opposite directions. The driving pawl levers 44 are rigidly connected with the shafts 42, while the pawls 45 proper are rockably mounted on the levers 44. The pawls are loaded by springs in order to assure engagement with the teeth of the gear rims 25. In the operative position the pawls 45 bear with their ribs. 46 against counter rib 47 of the pawl levers 44. The end position of the pawls 45 is thus fixed.

Fig. 10 showsseparately the position of the driving elements (pawl levers and pawls) for eachgrate ring. As shown in this figure, each ring is separately driven. In order not to crowd the drawing the rings have been shown without their grating surfaces while only fragments of the circular carriers 24 have been illustrated. The rocking movements of the connecting or push rods 40 are advantageously produced by hydraulic or mechanical driving mechanisms'known per so which are adjustable in steplessmanner. For this reason these driving mechanisms have not beenshown.

Fig. ,6, showing a cross-section through the cooling device above the grating elements, illustrates the hot air zones 18, 19 and 20. V

Fig. 11 is a schematic illustration of a different embodiment of a rotary grate cooler made in accordance with the invention. The upper portion of the cooler is identical with the cooler described in the previous embodiment, so that. no further description thereof will The same reference numerals as in the first have been employed for like parts. However, the rotatable disc 13 of the embodiment shown in Fig. 1, has been replaced by an additional lower rotary grating unit 31 which, regarded from thedirection' of feed of the clinker, constitutes a reversal of the upper grating arrangement. That is to say, the clinker does not fall into the hollow of a stepped hollow cone; but rather falls onto the outer surface of a downwardly stepped cone formed by the several grate rings; The center of this lower grating arrangement is charged with clinker material through the duct 12. Due to rotation of the grate rings of the arrangement 31, the clinker is outwardly conducted away from the center. The clinker is scraped from the marginal portion of the lowermost ring of the unit 31 by a stripper element 15 soas to be dropped upon the conveyor 17. However, it is also possible to conduct the clinker by overflow from anypoint on this lowermost ring to the conveyor 17, for example, by arranging a'chute' or the like below the grating unit 31. As in the upper grating unit, cooling airis introduced through nozzles 01" the likeinto the clinker mass passing over the lower grating unit 31.

In order to keep the quantities of employed cooling air within reasonable limits, the cooling air entering at 35 passes through grating unit 31 as shown by the arrows 36, and is then drawn into a blower 38 in the direction of the arrow 37. From the blower 38, the air is blown in the direction of arrow 39 under gratings 7, 8 and 9, from whence it follows the path shown in the first embodiment of Fig. 1. The cooling air introduced through nozzles and 11 is, however, produced in a separate blower.

Fig. 12 illustrates a further embodiment of rotary grate cooler. In this embodiment only the outer ring 7 is employed and the clinker material is pushed from all sides into a funnel-shaped hollow cone. The side walls of this hollow cone are made up of plates 32 which are arranged in an inclined manner. These plates form in conjunction with each other slot-shaped openings for the passage of cooling air. The angle of the cone wall is designed to correspond to the natural angle of the material, i.e., the clinker, being loosely deposited on the grating. In this embodiment, replacement of the grate plates can be made in a particularly easy manner. Further, there are present less elements which are subject to wear, all of the elements are constructed in a particularly simple manner, and work stoppages due to repairs are practically avoided.

For the purpose of obtaining a better cooling effect, a hollow cylinder 34 is built into the duct 12. This cylinder 34 has deflecting plates similar to those of duct 12, and it may be stationarily arranged or may be corotatably connected to the rotatable disc 13. For the purpose of providing an even more effective cooling, the cylinder may be charged within air as illustrated in Fig. 12. In doing so, the air enters the cylinder 34 from the space 48 through the clinker layer in the duct 12. The air is supplied to the space 48 as in the other embodiments.

A still further modification of a rotary grate cooler is shown in Fig. 13.

In this embodiment a hollow cylinder 34 is arranged directly beneath the outer grate ring 7. The radii of the confining walls of the cylinder are relatively large. As compared with the embodiment of Fig. 12, no hollow cone is provided. The embodiment of Fig. 13 permits the construction of grate coolers having the same base surface. The height of the cylinder 34 is altered dependent on the cooling effect which is required. This cylinder comprises a large cooling area accommodated within the smallest possible space. The cooling area is constituted by very simple elements. The clinker material falls downwardly by gravity between the outer and inner wall elements of the cylinder 34. The cooling necessary. embodiment airentersthe clinker from space 49 through the elements of the outer cylinder wall, while the air escapes through the elements of the inner cylinder wall into space 20. As in the other embodiments the air is supplied through blowers. This modification operates substantially as the previously described constructions.

The grate structure of the invention, due to its cooling effect on the cement clinker, exhibits an important and beneficial influence on the quality of the cement. Further, the production costs of the cement are considerably reduced, since considerably less fuel is. consumed. At the same time the area and the manufacturing costs of thecooler proper are reduced.

The rotary grate cooler of the invention is suitable for all materials which are to be heated by a firing or burning process and which are to be cooled by atmospheric air. A further important advantage of the cooler resides in the fact that the cooling can be etfeeted within a very small space, to such an extent that the cooled clinker may be conveyed on rubber conveying belts or the like without causing heat damage thereto.

I have described preferred embodiments of my invention, but it is understood that this disclosure is for the purpose of illustration only, and that various omissions and changes in shape, construction, proportion and arrangement of parts, as well as the substitution of equivalent elements for the arrangement shown and described, may be made without departing from the spirit and scope of the invention as recited in the appended claims.

What is claimed is:

1. Apparatus for cooling calcined cement clinker and like grainy materials, said apparatus comprising a spiral shaped confining cooler wall, means for feeding material to be cooled along said cooler wall, a plurality of rotatable ring-like members arranged below said cooler wall, said ring-like members being arranged eccentrically relative to each other, means for separately rotating said ring-like members at varying speeds and in dillerent directions of rotation to convey the material to be cooled to the center of the cooler apparatus, and means for continuously introducing cooling air through the confining wall and through said ring-like members.

2. Apparatus for cooling cement clinker according to claim 1, in which said ring-like members are covered with grating elements, having means to prevent the clinker material from falling through the walls thereof, and said ring-like members with their grates being staggered in such a manner that they are capable to support the clinker falling thereon in a manner of a hollow cone, the total inclination of said cone corresponding to the natural angle of the material supplied to the cooler.

3. Apparatus for cooling cement clinker according to claim 1, in which a pair of vertically-arranged cylinders forming an annular passage for the material to be cooled, are positioned outwardly of the outermost ring-like member, said cylinders having inclined, interchangeable, stepped grating elements, the air-introducing means including means for blowing cooling air between said grating elements into the mass of material to be cooled.

4. Apparatus for cooling cement clinker according to claim 1, wherein said means for feeding material comprises an inclined chute through which the material to be cooled is fed to the cooler, said chute having nozzlelike slots for admission of cooling air therethrough.

5. Apparatus for cooling cement clinker according to claim 1, in which the ring-like members are covered by interchangeable, segment-shaped plates having depcnding cooling ribs, the air-introducing means supplying a flow of cooling air between the cooling ribs, said plates having depending vertical walls facing the center of the cooler, said vertical walls having nozzle-like slots positioned to permit the cooling air to flow through the material to be'cooled.

6. Apparatus for cooling cement clinker according to claim 1, in which the cooler has a vertical delivery duct positioned within and depending .fromthe innermost ring-like membengthe bottomof said duct opening above a rotatable disc, .the disc being sized and'spaced below the lower edge of the duct a sufiicient distance to permit a piling of the material .to be cooled thereon without trickling of the material oil .the edge of the disc, and an adjustable stripper arranged .to strip the material from the disc upon rotation of the latter.

7. Apparatus for cooling cement clinker according to claim 6 in which the rotatable disc is formed of a plurality of eccentrically-rnounted grate rings, each comprising a plurality of segment-shaped plates, and adjustable means for driving said rings at varying rotational speeds relative to each other, the rings forming a downwardlystepped cone, the angle of inclination of said cone corresponding to the natural angle of the material to be cooled.

8. Apparatus for cooling cement according to claim lfi,

in which a cooling space is provided above said ;;grate rings and a cylindricalseparating wall divides said cooling space into cooling zones, said separating Wall having an air-cooled lower edge portion positioned to contact the upper surface of the material to be cooled, and cute 8. le shawl s i d h s oo in zo s to nduct away the cooling air therein.

:9. Apparatus for vcooling cement clinker according to claim-.8, in which the separating wall .is ,provided with openings connecting the cooling zones and-adjustable References Cit ed inthefile of this patent UNITED STATES PATENTS 1,558,11? Sherban' Oct. 20, 1925 1,718,243 Lindhard June 25, 1929 1,989,662 I Bernhard et 211-. Feb. 5, 1935 2,153,112. Windecker .Apr. 4, 1939 2,641,064 Foner June 9, 1953 Zimmermann Feb. 16, 1954'

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