US2024453A - Treatment of solid material with gaseous media - Google Patents

Description

Dec. 17,1935. M.IVOGIEL-JYORGENSENI, 2,

TREATMENT OF SOLID MATERIAL WITH GASEOUS MEDIA Filed July 5, 1933 5 sheets-snee 1 Dec. 17, 1935. M. VOGEL-JORGENSEN 2,024,453

TREATMENT OF SOLID MATERIAL WI TH GASEOUS MEDIA FiledJuly 5, 1935 5 Sheets-Sheet 2 I ATTORN Y5 Dec. 17, 1935.

M. VOGEL-JORGENSEN TREATMENT OF SOLID MATERIAL WITH GASEOUS MEDIA Filed July 5, 1953' 5 Sheets-Sheet 5 INVENTOR V I m Dec. 17, 1935.

M. ,VOGEL-JORGENSEN TREATMENI' 'OF SOLID MATERIAL WITH GASEOUS MEDIA Filed July 5, 1933' 5 Sheets-Sheet 4 ATTORN EYS Dec. 17, 35. M. VQGEL-JORGENSEN ,0

TREATMENT OF SOLIDMATERIAL WITH egsfious MEDIA Filed July 5, 1933 Patented Dec, 17, 1935 UNITED STATES TREATMENT or SOLID MATERIAL wrrn aseous MEDIA Mikael Vogel-Jorgensen, Copenhagen, Denmark, assignor'to E. L. Smidth & 00., New York, N. Y., a corporation of New Jersey Application July 5,1933, Serial No. 679,025

- In Great Britain July 6, 1932 3 Claims.

, In the treatment of solid material, such, for example, as cement raw material, with gaseous media, such, for example,'as air or. the gaseous products of combustion in the manufacture of v 5 cement, or other gases, as for the purpose of heating or cooling the material or for the bringing about of chemical reactions between the material and the gaseous media, or for the removal, as from the hot products of combustion in cement kilns, of solid substances, such as cement dust, the gaseous media'are sometimes caused to penetrate a layer of the material while the same is resting, under the influence of gravity, on a grate or-other reticular or perforated carrier In such operations as practiced hithersurface. 7

to difliculties have arisen, as when the solid material has to be moved onward during or after subjection to the action of the gases. The endless traveling conveyors-or grates which have 1 beenused in such operations have involved the installation of structures of great expense and of great weight which are subjected in use to considerablewear and particularly to deteriora-.

tion whenfthe'solid materials are treated with gases of high temperature. One particular disadvantagein the use of such endless traveling conveyors has been that only one-half of the conveyor could be used for the support of the material at one time, the return portion of such endless conveyors serving no function in the support of the material. The present invention has for its object to provide improved apparatus for the treatment of solid materials in granular or coarsely granular form which can be spread into layersto be penetrated by the gaseous media. v

Inaccordance with the inventiomthe material,

in granular or coarsely granular form, is applied veyor in excess of thepressure against'the other surface of the conveyor, such pressure diiterence, whether produced by positive pressure on 50 the one side of the conveyor or by negative pressure or suction on the other side serving to hold the material upon the working surface of the conveyor, even against the action of gravity,- until the material reaches the point at which it 55" is to be released or discharged from the conveyor,

such release'or discharge being accomplished by destroying the pressure difference at the point of discharge. It has been found in practice that if the grain size of the materialjunder treatment is suitable it is possible to hold against the work- 5 ing surface of the conveyor, by the gas stream alone, a layer of material sufficiently thick to enable the purpose of the invention to be realized.

If the carrier or conveyor-ism the form of an endless belt conveyor or -traveling grate it thus 10,,

becomes possible to use not only the upper side of the conveyor for the reception of a layer of the material but. also the under or returningside of the conveyor, increased. efficiency being thereby attained. It will. be noted further that the l5 ultimate removal of the material from the conveyor at the point of discharge is readily effected as it will be necessary only to abate the pressure difference at the predetermined point of discharge and thereby to permit the material to 20 drop from the working surface of the-conveyor under the influence of gravity. It will be understood'that in the practice of the invention the invention is not limited to the use of endless conveyors but can be realized with a rotary body 25 of any shape, such, for example, as a drum with perforated or reticular periphery) serving asthe carrier for the layer of material to be, treated;

the whole surface of such a body, except at the point atwhicli the material is to be discharged, 30 being covered by the layer of material. The discharge of the material from such a carrier may be effected either by interrupting the supp y of air under pressure at the predetermined. point at which the action of gravity may cause the 3 material to drop from the carrier, or by blowing the material from the carrierjby air supplied under pressure against the rear oropposite face a of the carrier. In, order that the material may size of. the material, which 'should therefore-be reduced, jingeneral, as far as may be consistent with the consumption of energy necessary for causing the movement of the air or other gaseous medium through the material. In practice it has been found in some cases that. a grain size of about one millimetre is to be recommended, While in other'case's'grains of the size of peas,

for example, or mixtures of grains of different sizes may be desirable.-

The invention may be with particular advantage applied in connection with rotary kilns, such as those employed in the manufacture of cement, in order that use may be made of the considerable amount of heat carried by the'combustion gases which leave the kiln. In the manufacture of cement by the dry process such gases carry with them a considerable quantity of dust and in such cases it is desirable to reduce the grain size of the material which forms the layer on the conveyor so that the layer serves not only to take up heat from the kiln, but at the same time serves as a filter to reduce substantially the amount of dust carried along by the gases.

In order that the invention may be clearly understood andreadily carried into eti'ect several forms of apparatus in which the invention may be realized will now be described by way of example with reference tothe accompanying drawings, in which:

Figure 1 is a view in longitudinal section illustrating the application of one embodiment of the invention to a rotary kiln.'

Figure 2 is a view in vertical section on the broken line 2-2 of Figure 1.

Figure 3 is a viewsimiiar to Figure '1, but illustrating the application of a rotary kiln in a somewhat different manner of that embodiment of the invention which is illustrated in Figures 1 and 2.

Figures 4 and 5 are views in section on the planes indicated respectively by the broken lines 4-4 and 5-5 of Figure 3.

Figure 6 is also a view similar to Figure 1, but illustratingthe application to a rotary kiln of a different embodiment of the invention.

Figure 7 is a view in transverse section on th plane indicated by the broken line I-l of Figure 6.

Figure 8 is a view in longitudinal section showing another embodiment of the invention.

Figure 9 is a partial view in transverse section on the plane indicated by the broken line 9-9 of Figure 8.

Figure 10 is a view mainly in elevation, partly broken out and partly in section, illustrating the application of the invention to a kiln in which provisions is made for rotation of thekiln or a portion of the kiln and the preliminary drier, with a portion of the kiln, at diii'erent speeds and in axial alignment.

Figure 11 is a partial view illustrating an arrangement similar to that represented in Figure 10, but with the two parts of the kiln out of alignment. y

Figure 12 is a view in sectional elevation illustrating a further embodiment of the invention in connection with a kiln, :a portion of which is also shown.

Figure 13 is a view in transverse section on the plane indicated by'the broken line I 3-H of Figure 12.

Figure 14 is a view in transverse section on the plane indicated by the broken line ll-l4 of Figure 12.

Figures 15, 16 and 17 are detail views of the partly or wholly. -In this instance the material is supplied through a chute 4 to a trough l0 in which rotates a worm'conveyor III which serves to apply the material to be treated to the outer surface of a drum or cylindrical carrier supported by a shaft 2 within a fixed casing 3 which forms a continuation of the stackor dust chamber l2 into which the hot products of combustion pass from the kiln I2. Within the drum or carrier 1 is supported a hood 1 which is in communication with the atmosphere or a source of air or gas under pressure through a pipe 8. The hot products of combustion from the kiln pass from the outside of the drum or carrier I through the perforated periphery of the drum and through, the layer of material held against the same by the pressure of such prod- I ucts of combustion and pass out from the interior of the drum through the conduit 6. The material which is released from the carrier through the abatement by the hood 1 of the pressure of such gases of combustion over a small area of the drum may be directed through a chute 13 into the kiln for further treatment therein.

In the embodiment of the invention shown in Figures 3, 4 and 5 that embodiment of the invention which is shown in Figures 1 and 2 is illustrated as arranged in axial alignment with the kiln instead of being placed higher than the kiln and discharging the heated material into the kiln by gravity. In this instance the material is supplied through a chute 4 .to a trough It in which rotates a worm conveyor In which serves to apply the material to be treated to the outer surface of a drum or cylindrical carrier l which in this instance is supported in axial alignment with the kiln l2 within an enlarged portion 3 which may be formed with t kiln shell. Within. the drum or carrier I is supported a hood 1 which is in communication with the atmosphere or a source of air orabatement of the pressure difference under the I hood I and passes through the openings left at the perimeter of the wall I is taken up by lifters M and discharged into the kiln. The hot products of combustion from the kiln pass in the opposite direction through the openings at the perimeter of the wall I and through the layer of material which is held by the pressure of such gases upon the outside of the carrier and thence from the interior of the carrier on the way toward the stack.

In the embodiment oi the invention illustrated in Figures 6 and 7, in which the perforated or reticulated drum or carrier I e is also arranged in axial alignment with the kihi l2, the material is supplied to the drum or carrier through a chute 4 to a trough ID in which rotates a' worm conveyor I (I by which the material is applied to the inner surface of the drum or carrier I and is held against such inner surface in a relatively thin layer by the pressure of the combustion gases which enter the carrier from the kiln, which is placed within a housing 3 which may be formed with the shell of the kiln. A hood 1", in communication with the atmosphere or a source of air or gas under pressure through. a pipe 8, is applied to the exterior of the drum or carrier and the material released from the inner surface of the carrier by abatement of the pressure diflerence falls upon an inclined chute in by which it is directed into the kiln. The hot combustion gases which pass through the layer of material and through the perforated or reticulated perimeter of the car- 'rier maybe discharged from the interior of the I! which are projected through the shield l8 of the kiln into an enlarged housing l9 carried with the kiln 20. In order to insureequal distribution of thematerial the .two impeller conveyors l6 and I! are of unequal lengths anddischarge through separate chutes l6 and l! at different points of a distributor conveyor at 2| which rotates in a trough 22, the lip 23 of which is arranged in proximity to the inner surface of the perforated or reticulated 'cylindricaldrum or carrier 24 so that the material shall be deposited upon the inner surface of the carrier slightly in advance of the lowest point of the carrier. A

curtain of chains '25 may be attached to the underside of the trough 22 for the purpose of insuring the spreading of the material upon the inner surface of the carrier in a layer of uniform thickness. under the influence of the pressure difference induced by suction, pass through the layer of material on .the inner surface of the carrier and through the carrier into an annular chamber 26 which may be in communication with the stack. At a convenient pointin advance of the conveyor 2| and trough 22 is placed against the exterior of the carrier a hood 21 which may be in communication with the atmosphere or with a source of air or gas under pressure through a pipe 28. By the admission of air or gas at this pointthe pressure which, so far in the rotation of thecarrier, has served to hold the layer of material against the inner face of the carrier, is abated and the material is discharged from the carrier into a trough 29, in which rotates a screw conveyor 30 by which the dried and heated ma-' for rotation of the main part of the kiln and the preliminary drier at different speeds, as shown in Figures 10 and 11. As shown in'Figure 10- the mainpart 22 of the kiln and thepart 33 which carries the preliminary drier 34 are supported independently of each other and in alignment, as to the two parts of the kiln, so

that they can be rotated at different speeds, as by the usual gearing indicated at 35 and 26, suitable provision being made for transfer of the material from the part 22 to the part 22, as. by scoops indicated at 31. The preliminary drier, in this instance, is indicated as of the same construction as that shown in Figures 3; 4 and d requires no detailed description herein.

While in Figure the two parts of the kiln are shown in axial alignment, it is obvious that they maybe displaced out of alignment, as shown in Figure 11, in which the two parts 28 and 29 are shown as displaced axially, as capable Thehot gases of combustion,

of rotation at different-speeds, and as provided, as at 40, with suitable means for the transfer of materialfrom one part to the other.

In the embodiment of the invention illustrated in Figures 12-17 the main body 50 of the kilns is shownas having a-conical extension 50 provided internally with flights 5i and terminating in an enlarged cylindrical section 49 which is provided with radial plates. 52 to support the. grate or traveling perforated carrier 54. The 10 section 49 is also provided with an annular casting 52 which serves as a peripheral gas discharge, the webs 52 of this casting 52 being in alignment with the radial partition plates 53 so as to provide longitudinal channels through which the hot gases, after they have passed through the grate or carrier 54 and the layer of material supported thereon, are conducted to the annular gas outlet 52. The annular gas outlet is provided with a mantle 59 which forms a seal for the gas discharge 'ring, the portion of the mantle which is in immediate contact with the gas discharge ring being relatively movable to adjust itself to expansions and contractions of the 'kiln while the lower part 60 is stationary and provided with an outlet 6| for connection to an induced draft fan, not necessary to be shown, and with a water seal 50. The mantle 59 also forms a support for the hood 55 through which 'air is admitted to abate the pressure with which the layer of material is held against the grate and permit it to fall, under the influence of gravity and of the air pressure into the trough The hood may be'pivoted at 55 so that it will be caused by its own weight to ride in close 85 contact upon the flanges of the gas discharge ring 52, and it may be provided with a connection, as at 56, through which air may be-discil'iarged into the hood under pressure. There is a so pivoted upon the mantle, as at 51, a hinged cover or guard plate 51 to prevent the escape of the gaseous medium from a point just below the hood 55 to a point somewhat lower down, the cover or guard'plate being held in close contact with the discharge ring 52'by meansof an adjustable counterweight 59 mounted on an arm' 58" secured to the cover.

In the embodiment of the invention the raw material tobe treated is fedfithrough a spout 40 into a pug mill-4| from which it passes to a dis-- 60 j integrator and distributor 42 in which is placed 1 a toothed drum 42', rotated at high speed, by

which the materialis discharged over trajectory bars 42, adjustably supported, as at43r, through .a feed inlet opening in the hood 45. By this means the material is distributedupon the'immediate surface of the grate or carrier- 54 in a layer of uniform thickness;

' Within the trough 62 is mounted ascrewconveyor 52 by which the material, which has been subjected to the action of the hot gases and has been discharged from the working surface of the carrier grate 54, is delivered through a chute 6Q into the kiln. The conveyor 52 'is preferably provided with a hollow shaft 62 for the passage of cooling air. It will be observed that the trough 52 is mounted upon a hollow casting: 65 provided with a pipe 55' for the on of cooling air. It will also be noted that an asbestos lined shield 54 is provided for the protec-,

tion of the parts from the action of the hot'gas'es. The hood 45and the parts carried thereby may be mounted upon a supporting' carriage 45 arranged -for movement on rails 41.

In the operation of this embodiment of the invention the material distributed uponthe inner surface of the carrier grate 54 is immediate- 1y subjected to the action of the hot gases from the kiln such gases passing through the layer of material and the grate into the channels formed by the partition'plates 53 and thence into the mantle 59 through the discharge ring 52. The gases so received in the mantle are discharged either into a dust chamber or directly into the stack under the influence of a fan not necessary to be shown. Under the pressure difference created by the induced draft fan the material clings to the grate 54 until it reaches the hood 55 where the pressure difference is abated and the material is permitted to fall under the influence of gravity and of the air pressure into the trough 62. 'As the channels formed by the radial partition plates 53 register successively with the opening in the 'dicharge hood 55 air under pressure entering the pipe 56 causes the pressure which has theretofore held the material upon the carrier grate to be abated and permit its discharge into the trough 62 whence it is conveyed into the kiln through the chute 66. As there is no layer of material on the carrier grate between the discharge hood, 55 and the point at which the material is to be fed to the carrier grate the gas channels 52 are sealed against'the action of the induced draft thereby preventing the escape of the gaseous medium until the layer of material has been formed on the grate.

Other embodiments of the invention will readily suggest themselves and it will be understood that the essential elements will be formed and disposed to suit the conditions of use and that,

except as pointed out in the accompanyinglip of the conveyor uponthe inner surface of the carrier in advance of the lowest point in the rotation of the carrier, a hood applied to the exterior surface of the carrier in advance of said trough and in communication with the air, a second trough and conveyor arranged to receive the material released from the inner surface of the carrier at the hood, means to direct gases to the interior of the carrier and cause such products of combustion to penetrate the carrier and the layer of material on the inner surface thereof, and means to conduct the hot products of combustion away from the exterior of the carrier.

2. The combination of a rotary drum-like perforated carrier, a trough within the carrier and having a discharge lip in close proximity to the inner surface of the carrier, a distributor within the trough to discharge the material over the lip of the conveyor upon the inner surface of the carrier in advance of the lowest point in the rotation of the carrier, a hood applied to the exterior surface of the carrier in advance of said trough and in communication with the air, a second trough and conveyor arranged to receive the material released from the inner surface of the carrier at the hood, means to direct gases to the interior of the carrier and cause such products of combustion to penetrate the carrier and the layer of material on the inner surface thereof, means to conduct the hot products of combustion away from the exterior of the carrier, and a curtain of chains suspended from the first named trough to insure uniform distribution of the material upon the inner surface of the carrier.

3. The combination of a kiln, means for forming a porous mass of cement raw material, a rotary drum-like perforated carrier, means to distribute the material in the form of a layer on the perforated surface of the carrier, means to cause the kiln gases to pass through the material and the carrier and to press the material against the carrier, means to establish a difference of pressure as between the two sides of the carrier, whereby the material is released from the carrier at a predetermined point in the rotation of the carrier, and means to deliver the released material into the kiln.

MIKAEL VOGEL-JORGENSEN.

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