US2268296A - Cooling apparatus - Google Patents

Description

Dec. 30, 1941- J. NARSTED EI'AL COOLING APPARATUS 4 Shee'ts-Sheet 1 Filed March 1, 1939 INVTORS ATTORNEYS Dec. 30, 1941. J. NARSTED ETAL COOLING APPARATUS Filed March 1, 1959 4 Sheets-Sheet 2 lNVENTORj R O A Dec. 30, 1941.

J. NARSTED ETAL 2,268,296

COOLING APPARATUS Filed March 1, 1959 4 Sheets-Sheet 3 E J0 E 47 Z4 33 J/ m *2 6 ll 1 5 E J0 6? J 1 5 4 g 68 73 as? W VII '1 kmmmlmm 3 73 /E M5 54 ATTORNEYS Dec. 30, 1941. J. NARSTED ET AL 2,268,296

COOLING APPARATUS Filed March 1, 1939 4 Sheets-Sheet 4 ATTO R N EY5 Patentecl Dec. 3t), 1941 coosnzo Arrsm'rps llohn Narstcd, Montreal,

Povl ll. Lind, h F. L. Smidth n has, his

tion oi-New .llersey Application 1 ll (line.

This invention relates to apparatus for cooling, or otherwise treating, material in rotary drums by gaseous fluids.

MM ill N, w Yorh, N. W a

uchcc, @anada, and ignore to lit-l coral rich ll, i939, he! No. 259,292

(til.- di -W5) to compartments at the interior suri'ace oi the shell and thence through the material, the easeous fluid being introduced principally through those shell openings which at the time lie under the material in the drum.

In accordance with one phase oi our inven tion the wind-hon is supported solely by the rotary shell oi the drum preferably by means oi wheels associated with the wind-hon which operate on a track carried hy the shell, the wind hos being held relatively stationary as the shell rotates within it. no tar as this leature oi the invention is concerned the wind-hon preferably completely encircles the shell oi the drum, hut so far as other features oi the invention are con cerned it is immaterial whether it extends entirely around'the shell oi the drum or not:

The discharge outlet oi the wind-hon faces the drum shell, and the openings through the shell move directly under the wind hou and over its discharge outlet. The shell op 1: v positioned that when the air compartments within the shell are arranged in two circumien ential rows, each shell opening lies partly to one side of the partition which separates the rows of air compartments and partly to the other side thereof, so that the air admitted through the shell openings will be divided and part will pass to the air compartments at one side oi the partition while the rest will pass to the air vcompartments at its opposite side. Preferably, a hood is placed within the shell over each shell opening to prevent solid material from passing outwardly into the wind-box, and an adjustable plate is associated with the hood to change, when desired, the proportion of air admitted to the two rows of air compartments.

A barrier is positioned in the wind-box at either side of the place where air is admitted to it. Each barrier completely spans the passage through the wind-box and is adjustable circumferentially of it to adjust not only the circumferential length of the discharge outlet of the wind-box, but also thecircumferential length of the portion of the wind-box to which the air is admitted. Air is thus caused to flow principally through those shell openings which at the time lit lit

are opposite that portion of the wind-hon which lies between the two barriers, the arrangement he such that these particular shell openings are the ones which lie under the material with in the dr. Each barrier is provided with a rehle opeg to permit a small amount of air to pass lay it into the portion of thevwindhon heyond the harrier to cool the cover plates oi the air compartments which lie above the level oi the material in the drum.

The cover plates for the air compartments are curved or inclined so that the trailing edge oi one. cover plate will overlap the leading edge oi the succeed one to provide suitable slot-like ones through which air passes from the air compartments into the material within the d mo: Each oi the cover plates is secured at its center portion only to the shell oi the drum.

The invention includes certain other improvements hereinafter described.

@ur improved apparatus was designed especially ior use in cooling cement clinker by means of air, hut it may be used for other purposes, and with a gaseous fluid other than air, and even tor heating or chemically treating material rather than cooling it. "However, for convenience the apparatus will hereinafter be designated a cooler and the gaseous fluid will he referred to only as air.

in the accompanying drawings the improvemenis are illustrated in connection with the cooling section oi a rotary tubular kiln, but it will he understood that the improvements are applicable to a cooler that is separate and distinct i'rom the kiln.

in the drawings:

his 1 is a transverse vertical section through the improved cooler the section being taken on the line Il--i of Fig. 3;

Fig. 2 is a side elevation of the portion of the cooler shown in Fig. i:

Fig. 3 is a vertical longitudinal section through the cooler taken on the line tt of Fig. i;

Fig. i is a transverse section taken on the line t-t of Fig. 3 illustrating the manner in which the cover plates for the air compartments are mounted;

Fig. 5 is a longitudinal section through one of the barrier blocks employed in the wind-box;

Fig. 6 is an end view of the barrier block shown 'inFig.5;

Fig. 7 is an enlarged view of the upper portion of Fig. 3 with more of the parts shown in cross section;

Fig. 8 is a transverse section through the windbox .taken on the line 6-6 of Fig. l with the barrier blocks omitted;

Fig. 9 is a section taken on the line 39 of Fig. 7 illustrating the means for adjusting the wheeled shafts that carry the wind-box;

Fig. 10 is an end view of half of the cage that fits into the drum shell and forms the walls of the air compartments, this view. also. showing several sections of the sectional discharge ring;

Fig. 1l is a plan view of a portion of the cage as viewed outwardly from its central axis;

Fig. 12 is a longitudinal section through the cage taken on the line l2-l2 of Fig. 11;

Fig. 13 is a longitudinal section through the cage taken on the line I3l3 of Fig. 11;

Fig. 14 is a side elevation of a portion of one of the sectional air-seal rings for the wind-box;

Fig. 15 is a transverse section taken on the line l5 l5 of Fig. 14; and

Fig. 16 is a detail view illustrating the manner in which an air seal is effected at the adjoining ends of two sections of the air-seal ring shown in Fig. 14.

As above stated the improved cooler may be an independent one but in the drawings it is illustrated in connection with a rotary kiln of the drum type. The shell of the kiln is shown at i (Fig. 3) and has the usual lining 2. The shell is mounted to rotate about an axis which is slightly inclined to the horizontal so that the material in the kiln, such as cement clinker, feeds towards its lower discharge end as the kiln rotates. In the present instance the shell 3 of the cooler forms a continuation of the shell I of the kiln.

The shell of the cooler is provided with an external reinforcing band 4 (Figs. 3 and 7) 'preferably welded in place. A pair of flanges 6 are welded edgewise to the reinforcing band and to each of these flanges is secured one rail 6 of a track. Two pairs of wheels I (Figs. 1, 3and 7) are mounted to operate on the track formed by the rails 6. Each pair of wheels is mounted on a shaft 8. The two shafts 8 support an annular wind-box preferably formed by fastening together two side plates 9 and I0 (Fig. 7) and an outerplate i I. The wind-box is thus channeledshaped in cross section with the opening I 2 of the channel facing the shell 3 of the cooler. At spaced intervals within the wind-box are stiifening ribs ll provided with openings Ii" through which the air may pass. The annular wind-box thus formed is supported from the shafts 6 b5 bearings l3 so that the wind-box is acoommodated in the space between the two rails 6 of the track.

the cooler, as hereinafter described, but it will be noted from Fig. '7 that some of the air may pass laterally under the inner edges of the windbox plates 9 and i0 and would escape to the outside atmosphere if not prevented from doing so. We, therefore, provide an air-seal between the wind-box plates 9 and I0 and the corresponding track rails 6. .The air-seal between the plate I0 and the corresponding track rail 6 may comprise a sectional ring i8, the sections of which are bolted to a machined surface IS on the plate l0 by means of bolts 20. The outer face of the sectional ring l8 bears directly against the track rail 6. Figs. l4, l5 and 16 show the details of this sectional ring. There is a slight clearance between the ends of the ring sections, as shown in Figs. 14 and 16, through which air is prevented from leaking by means of a spring 2| (Fig. 16) positioned in longitudinal slots 22 at the joining ends of the ring sections.

A similar sectional air-seal ring 23 bears against the other track rail 6. In this case, however, it is clamped to the inner edge of a diaphragm 24 by means of a sectional clamping ring 25. The outer edge of the diaphragm 24 is clamped'by means of a sectional clamping ring 26 to a flange 21 carried by the outer plate ll of the wind-box. In addition to a number of cap screws which clamp the ring 25 to the ring 23 there are some special screws 28 which have inwardly projecting cylindrical heads 29 (Fig. 7) surrounding each of which is a helical spring 36. The springs 36 react against a machined surface 3| on the side plate 9 of the wind-box. It will thus be seen that the springs 30 force the sealing ring 23 against its corresponding track rail 6 and at the same time force the opposite sealing ring 18 against its corresponding The wind-box preferably completely encircles I the shell of the cooler, as best shown in Fig. 1, but so far as some of the features of the invention are concerned the wind-box may extend only partly around the cooler shell. When the wind-box completely encircles the cooler shell it is preferably formed in at least two sections for convenience in assembling. The sections may be bolted together at the flanges I 4 and i5 (Fig. 1).

The lower portion of the wind-box is connected to an elbow 16 forming part of an air conduit to which air is supplied by m'eans of a fan IT, or in any other suitable way. The junction of the elbow l6 and the wind-box thus constitutes the air inlet for the wind-box.

The major portion of the air leaving the windbox through its discharge opening l2 passes through certain openings provided in the shell 'of track rail 6. When the track formed by the rails 6 rotates with the cooler shell, the sealing rings l8 and 23 being carried by the wind-box and thus held stationary, make sliding contact with the inner faces of the track rails and thus together withlthe diaphragm 24 prevent any of the air that leaves the wind-box from passing to the outside atmosphere. Lubricant, may be supplied to the bearing faces of the sealing rings l8 and 23 by pipes l8 and 23', as best shown in Figs. 8 and 1 It will be noted that the wind-box is supported solely by the rotary shell of the cooler, the track and the wheels providing anti-friction means for accomplishing this. The wind-box remains stationary while the cooler shell rotates within it. To hold the wind-box stationary as the cooler shell rotates and to adjust its position circumferentially of the shell when necessary, the turn buckle shown in Fig.1 is employed. This may comprise right and left hand eyebolts a2 and a threaded into a long sleeve 34 and locked in position by locknuts 35 and 36. The upper eyebolt 32 is connected to a bracket 31 carried by the wind-box and the lower eyebolt 33 is connected to some fixed point, such as the floor, as

shown at 38. The sleeve 34 is provided with holes 39 by means of which the sleeve may be turned with a drift pin. It is obvious that by loosening the lock nuts 35 and 36 and by turning the sleeve 34 the wind-box may be moved a limited distance in either direction circumferentially about the shell of the cooler after which the lock nuts 35 and 36 may be tightened to hold the wind-box in fixed position. To permit this move ment ofth'e wind-box the air conduit between the elbow l6 and the fan II has a section made up of telescopic parts 38 and 40, the telescopic joint which may be sealed by a wrapping indicated at 4 I. The telescopic part of the conduit is connected to the elbow l6 by'a. connecting portion 42 and to the fan IT by a connecting portion 43. The joints between these connecting portions and the telescopic part of the conduit are loose ones as indicated at 44 and 45 so that the several portions of the conduit will adjust themselves to the new position of the wind-box. These loose Joints may be provided with a suitable wrapping 06 to prevent air leakage.

Each shaft 8, in addition to being mounted in the bearing iii, is guided by two forked brackets ll and 48 (Figs. 7 and 9) which are bolted respectively to the flange 21 at one side of the wind-box and to an extension 49 on the side plate it at the other side of the wind-box. Where the shaft t passes between the arms of the brackets ti and it it is provided with. machined surfaces ht (Fig. 9) on which rectangular washers ti fit. Each washer it is provided with a slot ti which engages with the bracket to prevent the washer from turning. The washers are also provided with holes into which the inner end of adjusting screws it are fitted, these adlusting screws being mounted in the forks of the bracket. By adjusting the screws til the shafts ii, and the wheels carried by them, may be slightly adjusted to cause the wheels to run true on the trash rails t. This adjustment of the shafts t is permitted by the nature of the hearings iii. After each shaft is adjusted by the screws $3 a slight clearance is left between the washers. iii and the machined surfaces ft on the shaft to permit the shaft to swing slightly (in the plane of the drawing). The bearings it are of such a nature as to permit this movement of the shafts. any irregularities. in the track and the shell are thus compensated for thereby causing the annular wind-box to ride properly on'the track following the motions of the shell. The shell may thus freely rotate within the annular wind-hon without disturbing its proper alignment.

The shell 3 of the cooler is provided with a series of openings (which also pass through the reinforcing band i) which move directly under the discharge opening it of the wind-box.

The air passing through these openings into the cooler first enters air compartments positioned at the interior surface of the; shell and which will now be described.

The side walls of the air compartments are formed by a cage which is assembled as shown in Figs. 10-13. The cage comprises longitudinal partitions t and end circumferential partitions it and 57. as we prefer to have two circumferential rows of air compartments instead of one, there is provided an intermediate partition 58 so positioned longitudinally of the shell that to the right of this partition. as viewed in Figs. 11-13, there is one circumferential row of relatively long air compartments, and to the left of this partition another circumferential row of relatively short air compartments. The longitudinal and circumferential partitions may be suitably interconnected by means of brackets 59 and splice plates 59a. Circumferential straps 59' and M" are provided which are made up of sections welded to the splice plates 591: secured to the longitudinal partitions. The cage is bolted to the shell by means of brackets 60.

Each of the shorter air compartments has one cover plate and each of the longer air compartwhich projects the eye of an eyebolt 63. A pin,

64 passes transversely through the walls of the boss 62 and through the eye in the eyebolt. The boss 62 rests upon a supporting block or pedestal 65 which is bolted to the shell as shown at 66 (Fig. 4). The upper portion of the supporting block 65 is provided with longitudinal ribs 61. between which the square -boss on the cover plate fits so as to prevent the cover plate from turning. The shank of the eyebolt 63 passes through a central opening it in the pedestal 65 and projects through the shell. t where a nut 69 is threaded on its extremity and thereby clamps the cover plate to the pedestal.

Each cover plate ti is inclined or curved from its leading edge tie to its trailing edge 6th toward the axis of the cooler (Fig. a). The trailing edge hit of each plate slightly overlaps the leading edge of tin of the succeeding plate so as to form a slot-like opening it through which air may escape from the air compartment under the cover plate into the interior of the cooler where it passes through the material therein, as hereinaiter described. The cover plates may, if desired, be provided with openings or slots ll through which air may also pass from the air compartments into the interior of the cooler. The cover plates are also preferably provided with strengthening ribs if. The adjoining ends of the cover plates ti lie over the circumferential straps it and ti".

A sectional discharge ring lit, bolted to the shell t as shown at ill, insures that a certain layer of material will remain on the cover plates iii during the operation of the apparatus.

It will be noted from Figs. 3 and 7 that the plane of the intermediate circumferential partition ht intersects each of the openings at in the cooler shell. in other words, one part of each of the openings it lies to one side of this partition while the remaining part lies to the other side of the partition. Thus the air entering the air compartments through the openings til would normally be divided so that part would flow to the short air compartments on one side of the partition and part would flow to the longer air compartments on the other side of the partition. However, over each opening hi there is a hood it (best shown in Fig. 7) which interrupts the continuity of the partition ht. These hoods are part of the cage as shown in Figs. 11 and i2 and are welded in place when the cage is assembled. Inside of each hood there is a plate M adjustably attached to the cover it of the hood by means of the bolt it. At either side of the plate l t the hood is provided with an opening ill. Thus the air entering the air compartments first passes through this hood and is divided by the plate M so that part of it passes through one hood opening H to the shorter air compartments while the rest passes through the other hood opening H to the longer air compartments. By adjusting the position of the plate H the proportion of air supplied to the two circumferential rows of air compartments may be changed. The hoods substantially prevent any solid material which gets in the air compartments from passing out into the wind-box while they permit free ingress of air from the wind-box into the air compartments.

Mounted within the annular wind-box at either side of the air inlet is a hollow barrier block it (Figs. 1 and These barriers completely span the passage through the wind-box and therefore determine by their position the circumferential length of that portion of the wind-box to which air is admitted. In other words, they do not merely adjust the circumferential length of the discharge opening I 2 of the wind-box but they also adjust the circumferential length or volume of the effective part of the wind-box. Each barrier block may be adjusted circumferentially of the wind-box by means of a cap screw I9 which projects through a slot 80 (Fig. 2) in the outer wall ll of the wind-box. A washer Ii prevents the escape of air through this slot. By loosening the cap screw I9 each barrier block may be adjusted a limited amount circumferentially of the wind-box and is held in adjusted position when the cap nut is tightened. It is obvious that the distance between the two barrier blocks will determine the number of openings 54 in the cooler shell through which air is permitted to pass at any one time into the interior of the cooler, In other words, direct air supply is substantially cut off to all of the openings 54 except those which are passing between the barrier blocks. During rotation of the cooler (in the direction of the arrow shown in Fig. l) the material indicated at M occupies a position somewhat as indicated in this figure, and the barrier blocks 18 are so positioned that the air will pass through those openings 54 which lie under the material when the cooler is rotating. It is desirable to let a small amount of air pass by the barrier blocks and into the portion of the wind-box beyond them so that it may cool the cover plates ii that happen to be above the level of the material. For this purpose the transverse wall of each barrier block is provided with an opening 82 (Figs. 5' and 6) which is controlled by a disc 83 threaded on a stem 84. By turning the disc 83 it may be moved toward or away from the opening 82 and it therefore acts as an adjustable valve to regulate the amount of air-permitted to pass through the opening 82.

Projecting outwardly from the side wall 9 of the wind-box are two partitions 85, one of which is shown in Fig. 8. One of these partitions is located near one barrier block 18 and the other one is located near the other barrier block, as indicated by the dotted lines in Fig. 1. The purpose of these partitions is to prevent the air which leaks around the inner edge of the wall 9, within the space bounded by the barrier blocks 18, from passing too freely into the rest of the annular wind-box.

When the annular wind-box has been adjusted to its-proper circumferential position by turning the sleeve 34 of the turn buckle, and has been locked in proper position by the lock nuts 35 and 36, and when the barrier blocks 18 have been adjusted to their proper positions to permit air to flow through the desirednumber of openings in the shell, and when the adjusting plates 14 in the hoods I3 have been properly set, the apparatus is ready to operate. Air from the fan l'l passes into the annular wind-box and then through the openings 54 which are in the zone between the two barrier blocks 18, and into the corresponding air compartments. If there is only one circumferential row of air compartments all of the air passing through one of the openings 54 passes into the air compartment with which that opening communicates. On the other hand, if there are two circumferentialrows of air compartments, as shown in the drawing, the

air passing through each shell opening 54 is di-- passes into the air compartment at the opposite side of this partition. The adjustment of the plate 14 will determine the proportion in which the air is admitted to the two compartments at opposite sides of the partition. In some cases it may be desirable to supply a large quantity of air to the circumferential row of compartments over which the material first passes upon leaving the kiln so as to produce a sudden air quenching of the hot material, and to supply a smaller quantity of air to the other row of compartments over which the material later passes to effect a slower cooling or the material in this part of the cooler. However, there may be other reasons for changing the distribution of air to the compartments of the two rows, or as above stated there may be only one circumferential row of air compartments in which case there would be no division of the air at all. Moreover, when two circumferential rows of air compartments are employed the compartments at opposite sides of the partition 58 may be of the same length, if so desired.

The air leaves the air compartments through the openings II in the cover plates and through the slot-like openings 10 formed between the overlapping edges of the plates and passes into and through the bed of material feeding through the cooler.

There is no contact between the rotating shell and the annular wind-box except at the sealing rings l8 and 23,' and there is no wear which might eventually change the adjustment of the passages, nor can any inaccuracies in the shell structure, caused for instance by warping due to heat, result in any change in the amount of air which passes through the bed of material.

While we have referred throughout the specification and claims to the use of air as the cooling medium, some other gaseous fluid may be used especially if the material to be treated is affected by oxygen.

It is to be understood that no limitation is-intended where the claims refer to the gaseous fluid as air," since this term is used simply for convenience to mean any gaseous fluid whether a cooling fluid, a heating one, or one which affects a chemical treatment of the material.

We claim:

1. The combination of a cylindrical shell rotatable about a generally horizontal axis, a relatively stationary annular wind-box encircling the shell, means for admitting air from the wind-box through the shell into the interior of the shell. and anti-friction means operatively interposed between the shell and wind-box, the shell acting through said anti-friction means to provide the sole support for the wind-box.

2. The combination of a cylindrical shell rotatable about a generally horizontal axis. a relatively stationary annular wind-box encircling the shell, means for supporting the wind-box solely by the shell comprising a track mounted on one of said parts and wheels mounted on the other of said parts and running on the track, and means for admitting air from the wind-box through the shell into the interior of the same.

3. The combination of a cylindrical shell ro- I tatable about a generally horizontal axis, a track carried by and encircling said shell, wheels operating on said track, an annular wind-boxrencircling said shell and supported by said wheels on said track, means for. holding the wind-box stationary as the shell rotates, and means for admitting air from the wind-box through the shell into the interior of the same.

4. The. combination of a cylindrical shell rotatable about a generally horizontal axis, a pair of track rails carried by and encircling said shell, at least one pair of wheels operating on the track, a shaft on which said wheels are mounted, an annular wind-box encircling said shell and located between said track rails and supported from said shaft, means for holding the wind-box stationary as the shell rotates, and means for admitting air from the wind-box through the shell into the interior of the same.

5. The combination of a rotatable cylindrical shell, a relatively stationary wind-box at least partly encircling the shell and having a circumferentially elongated discharge opening, the shell having a series of openings adapted to communicate with said discharge opening and through which air may pass from the wind-box into the interior of the shell, an air inlet for the windbox, means interposed between the wind-box and shell through which the shell acts to provide the sole support for the wind-box, and means connected to the wind-box and to a fixed point and operable for adjusting the wind-box circumferentially of the shell.

6. The combination of a rotatable cylindrical shell, a relatively stationary wind-box at least partly encircling the shell and having spaced side walls and a circumferentially elongated discharge opening in its side facing the shell, the shell having a series of openings lying between the side walls of the wind-box and registering successively with said discharge opening as the shell rotates to permit air from the wind-box to pass into the interior of the shell, an air inlet for the wind-box, and a barrier within the windbox at either side of said air inlet completely spanning the passage through the wind-box and adjustable circumferentially of the wind-box whereby the circumferential length of the portion of the wind-box to which air is admitted by said inlet may be adjusted.

7. The combination of a rotatable cylindrical shell, means at the interior surface of a portion of the shell forming two circumferential rows of air compartments, a circumferential partition separating the compartments of the two rows, said shell having a circumferential series of openings so positioned that one part of each opening lies to one side of said partition and the remaining part lies to the other side of the partition, and a relatively stationary wind-box at least partly encircling the shell and having a discharge opening facing the shell, said shell openings coming successively into registry with said discharge opening as the shell rotates whereby air discharged from the wind-box through the shell openings and into said air compartments is divided by said partition and part passes into the air compartments of the row at one side of the partition while the other part of the air passes into the air compartments of the row at the opposite side of the partition.

8. The combination of a cylindrical shell ro tatable about a generally horizontal axis, means at the interior surface of a portion of the shell forming at least one circumferential row of air compartments, said shell having a series of openings each of which communicates with one of said air compartments, a relatively stationary.

wind-box at least partly encircling the shell and having a discharge opening adapted to communicate with said shell openings, and a hood within said compartment at each shell opening for substantially preventing passage of solid material from the compartment into the wind-box while permitting air from the wind-box to enter the compartment, said hood including a part extending inward from the wall of the shell around the shell opening and having an air opening and another part spaced from the shell wall and overlying the shell opening.

9. The combination of a cylindrical shell rotatable about a generally horizontal axis, means at the interior surface of a portion of the shell forming two circumferential rows of air compartments, a circumferential partition separating the compartments of the two rows, said shell having a circumferential series of openings so positioned that one part of each opening lies to one side of said partition and the remaining part lies to the other side of the partition, a relatively stationary wind-box at least partly encircling the shell and having a discharge opening facing the shell and under which said shell openings are adapted to move, a hood for each of said shell openings projecting within the shell and substantially preventing passage of solid material from the air compartment into the wind-box but permitting passage of air from the wind-box into the air compartment, and adjustable means in said hood the relative proportions of air entering the compartments at opposite sides of said partition.

10. The combination of a rotatable cylindrical shell, a relatively stationary wind-box at least partly encircling the shell and having a circumferentially elongated discharge opening facing the shell, the shell having a series of openings adapted to move successively into registry with said discharge opening and through which air may pass from the wind-box into the interior of the shell, means for supporting the wind-box so that it is out of contact with the shell wall, and a seal for preventing escape of air from the windbox to the atmosphere including a pair of members mounted on the shell to encircle the latter and lying on either side of the wind-box and means on the wind-box extending throughout the length of the latter and making seating contact with the members.

11. The combination of a rotatable cylindrical shell, a relatively stationary wind-box at least partly encircling the shell, said wind-box being channel-shaped in cross-section with the opening in the channel facing the wall of the shell, the shell having a series of openings adapted to move directly into registry with said opening in the wind-box and through which air may pass from the wind-box into the interior of the shell, means for supporting the wind-box so that it is out of contact with the shell wall, a pair of members secured t0 the shell and projecting radially outward and between which the wind-box is positioned, and an air seal positioned between each of said members and the adjacent lateral wall of the wind-box.

12. The combination of a rotatable cylindrical shell, means at the interior surface of a portion of the shell forming two circumferential rows of air compartments, a circumferential partition separating the compartments of one row from those of the other, said shell having a circumferential series oi openings so positioned that one part of each opening lies at one side of said partition and the remaining part lies'at the other side oi said partition, a relatively stationary wind-box encircling at least part oi the shell and having a discharge opening racing the shell, said shell openings coming successively into registry with said discharge opening as the shell rotates to permit air from the wind-box; to flow through the shell openings and into said compartments, and adjustable means at each shell opening 101:

' varying the relative proportions oi the quantities of ntering the compartments at opposite sides of said partition. 4

to plate to said pedestal.

shell. lbnsitudinal andoimumierential partitions mounted against the inner surface oi. a portion oia shell and forming at least one circumferential row of air. compartments, a cover plate for each compartment. a pedestal secured to the shell in each compartment and lying in line with the central portion only of the cover plate, and means tor clamplns the central portion of the cover JOHN NARSTED. POVL T. LINDHARD.

' 13. The combination of a. rotating cylindrical CER'I'IFICIATEOF CORRECTION. Patent No.2,268,296. December 50, 191,1.

JOHN NARSTED, ET AL.

It is hereby certified that error appears in the'printed specification of the above numbered patent requiringcorrection as follows: Page 5, second column, line 514., claim 9, after "hood" insert --for regulat1ng--; and that the said Letters Petent should be read yvith this correction therein.

,that the .same may conform to the record of the case in the Patent Qfflce'.

Signed and sealed e113 5rd day. of March, A. 1 19h2.

Henry van Arsdale, (Se'al) Acting commiesioner of Patents.

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