US1709351A - Drier - Google Patents

Description

April 16. 1.929. M l|3, JONES 1,709,351

DRIER Filed NOV. 22, 1926 2 SheeLS--Shee'l ATTORNEY M. D. JONES April 16, 1929.

DRIER Filed Nov. 22, 1926 2 Sheets-Sheet ATTORNEYJ' Patented Apr. 16, 1929.

vu Nrlrrn -sTATf-S PATENT OFFICE.

MICHAEL yD. JONES,; OE`,A LLENT,O,\VN, PENNSYLVANIA, ASSIGNOR TO FULLER-LEHIGH COMPANY, OF F'VULLEETON, PENNSYLVANIA, A. CORPORATION OF PENNSYLVANIA.

name.

Application ledNovember 22, 1926.

rlhis invention'relatesto driers for drying material, suchas coal and the like, and is concerned moreparticularly with driers of the type in which the materialtobe dried descends by gravity-through a housing and in such descent is subjected-to the action of a heating medium. More specifically, the present drier is arranged to utilize -lwaste gases of combustion, or -a mixtureof such gases and atmospheric air, as -the'drying medium, this mixture being preferably controlled in accordancefwith'the-process described inmy prior Patent, No. 1,568,738, dated January 5, 1926.

In driers of this general type, oneof the principal dificulties'tolbe overcome lies in securing an even and uniform flow ofthe material through the drier housing and any Vcompacting or piling up ofthe material within the housing results in an uneven drying eect, some of the -material being discharged from the housing in-moist or damp condition, while other portions oftherflow- Ying mass are raised to atemperatureabOVe Q that necessary to drive off the moisture. VIf

this compacting or piling up ofthe material in the housing continues, conditions rmay arise within the housing which will result in the material being ignited `and where this material is coalfthis may leadv to serious consequences.

Thepresent invention is directed to the provisionof a. drierby which materialmay be dried bythe direct action of a heating medium, the material I'iowing downwardly Hthrong-ha vcasing and the heating-medium being ladmitted soas topermeate thev stream. This drier is further"constructed land arrangedsothat'earehing or bridging of the material during its descent 'ris-avoidedand the flow ofl the materiali is y so controlled lthat the/material passes through the casingiina number of lseparate streams which move with equal velocity through all sections of -the drier housing, the` streams being united and subdividedV at frequent intervals so that the drying medium will act with maximum effect and in all horizontal sections through -the drier-the material will offer uniform resistance to the flow of the drying medium. Infadditionfthe drierof this invention is provided with means for controlling the flow. of the materialin such mannerthat the imaterial descends equally from all horizontal sections of the drier, thus i bringing Y about serial No. 149,833.

ya uniform discharge of the dried material and insuring an even drying action. The` invention further includes certain features of construction by which an even distribution of the heating medium throughout the descending' stream of material may be readily secured, as well as various other features whichwill be set forth in the Vdetailed description to follow. I

In one embodiment of the invention the drier includes a casing having an inlet open* ingat itstop -for admission of the material to be dried, and a hopper at itsbottom, the latter delivering -the materialto a discharge spout. The casing is lprovided Valong one side with a gas inlet duct and with a gas outlet duct at its opposite side. Extending between these opposite sides `within thedrier housing are inverted troughs or tunnels which are `arranged inA rows, with the troughs of one row staggered with reference to the troughs of the row above. All of the troughs in one row are connected by means of openingsl to the gas inlet duct ,and all of those of the next row are connected by openings to the gas outlet duct. Therwet material is introduced at thetop of the housing and flows therethrough bygravity. In its passage, the material 4is subdivided by the tunnels-into a plurality of streams and these streams are united and again subdivided by the next lower row of tunnels. The hot gases used enter the endo'fthe tunnels of one row, escape from the open bottoms thereof, and flow through the descending streams ofv material into the exhaust tunnels of thenext-higher row, and out of the end of the tunnels to the gas outlet duct. In such action the gases remove the moisture inthe material and carryit ofto the outlet. At-the bottom of the housing is a distributing` device, which `may. take lthe `form of al cone. VThis cone is so arranged with reference to the-hopper and the discharge spout, that the material is discharged evenly from all points in a horizontal plane through the drier at the lower end thereof, thus insuring a uniform iow of material throughout the drying chamber from the top to thebottom and preventing piling up.

When the drier is to be used or the drying of material which contains an excessive quantity of moisture so that uniform distribution of the material through the drier .is dilicult, the drying action of the hot gases may be supplemented by additional drying means acting on the-material at the top of the drying chamber. For this purpose the tunnels at the top of the chamber may be provided with pipesfor the iow of a heatv ing medium, such as steam, this supplementary heating medium acting indirectly on the material and with the hoty gases subjecting the material initially to a rapid drying action which will drive off muchV of the entrained moisture. This preliminary drying step removes a su'fhcient quantity of moisture so that the material may thereafter be distributed evenly throughout the chainber by the tunnels which lie below the group at the top in which the pipes are disposed.

For a better understanding of the invention, reference will be made to the accompanying drawings, in which Fig. 1 is a view in side elevation of one form of the drier, showing certain parts Vbroken away,

Fig. 2 is likewise a view in side elevation of the drier but taken at right angles toV Fig. 1,

Fig. 3 is a view of a portion of the drier in side elevation, showing the side opposite to that illustrated in Fig. 1,

Fig. 4 is a sectional view on the linee-a ofFig. 1, showing a portion of one of the tunnels,

Fig. 5 is a view in elevation of an end plate used in the construction of a drier tunnel, l

Fig. 6 is a similar view of a different type of plate used at the end of the tunnel opposite from that where the plate in Fig. 5 is emp1oyed,'and

Fig. 7 is a detail view of portions ot' the header construction used in the steam pipe section of the drier.

With reference new to the drawings, the drier is shown as consisting of a vertical casing, generally designated 10, and made up of plate members such as that designated 11 which have longitudinal iiangcs by which they may be bolted tog-"etherA This casing is of rectangular, section and is suitably mounted in any convenient manner. Along one side the casing is provided with a duct 12 for the introduction of heatinggases, and this duct may lead to any suitable source of supply. At the side of the drier opposite to that to which the inlet duct leads is an outlet duct 13 and a fan may be used in one or the other of the ducts for forcing the drying medium through the material, either by pressure or by suction.

f Thetop of the drying chamber is provided with a cover 14 on which is mounted a distributing hopper 15 for the introduction of the wet material, this hopper being Varranged to distribute the material evenly across the drying chamber. The material delivered by the hopper 15 iows down through the drier casing, around the inverted troughs or tunnels 16. These tunnels are arranged in alternate rows, with the tunnels of one row staggered with reference to those of the row beneath. Each tunnel is made up of a closed end plate 17, which is secured to the outside of the drier chamber, a duct section 18, and an apertured plate 19 which conforms to the shape of the duct section and is secured to the opposite side of the drier. The duct section and plates are preferably made of cast iron, sothat they will have a good resistance to corrosive action, and by making the tunnels in three parts, as described, their construction is greatly cheapened and their assembly is facilitated. The duct sections 1,8 preferably have serrated bottom portions as indicated at 20,'so that the material may flow freely past the tunnel and the drying medium may pass into this material at a number of places along the edge of the tunnel, instead of being short-circuited at one particular point.

rlhe tunnels of alternate rows are `reversed with reference to the disposition of the apertured plate, so that the Vtunnels of one row receive the heating medium flowing into the chamber from the inlet duct, andV this medium may flow? across the chamber in the tunnel, then escaping around the edges of Y the duct section and iowing up through the material tothe duct sections of the next higher row. These duct sections are connected with the @as outlet and permit the escape of thegases with the moisture which they have carried away from the material 'to be dried. Y

t the lower end of the chamber is a hopper 21 and connected to the lower end thereof is a discharge spout 22, here shown as extending from the hopper at an angle to the axis of .the latter.k rilhis hopper may be provided with the usual control gate, generally designated 28. rlhe material iiowing through the drier enters the hopper and is delivered through the discharge spout but the flow of the material into vthe hopper is controlled by a distributing device 24; which may take the form-of a cone supported within the casing just above the lower end of the latterron straps 25. This cone is arranged to force the discharging` material to flow toward the hopper walls, thus preventing a direct iow of the material at the center of the drier through the hopper and into the spout. In this manner the hopper offers resistance to the liow of material at the center of the descending column, thus equalizing the resistance to the flow of the material throughout any horizontal section in the drier. It will be apparent that but for the Vpresence of this distributing cone the material at ythe center ofthe descending column which liows almost directly toward the discharge spout would encounter much 'xiti lll) vless resistance than that ilowing the material [lowing along the walls of the chamber and then down the side walls of the hopper. Accordingly, material on the outer layer of the descending column would move much more slowly than that iiowing through the center thereof, with the result that the faster flowing material is likely lo bc discharged fi'oi the drier in relatively moist condition, wl 'le the outer .layer or' material or' the column is likely to be thoroughly dried and to have its teiiipeiature raised above the point/necessary to secure this condition ot' dryness.

When a discharge hopper is employed which extends at an angle to the axis of the casing, a hopper of special form may be used .in order to provide the desired uniform resistance to the flow ol the descending material. Such a hopper as this is illustrated in Fig. l, where it will be seen that the axis of the cone 24 and'of the drier casing are coincident, but the axis of the hopper' bot@ tom is ollset slightly to the left in the view from the oi the cone andl casing. The purpose of this arrangement is to place the discharge spout so that if a plane designated A-A is drawn through the discharge spout normal to the axis thereofat the entrance end of the spout, this plane cutting` all the walls of the spout, the axis of the cone, if extended, will pass through the center of the plane as indicated by the line B-B. lVit-h such an arrangement, it will be seen that the flowing material is prevented from building up on one side of the hopper, thus slowing down the flow through the corresponding side or' the drier. This follows because, although the axis` of the cone, as shown in Fig. l, lies closer to the side of the hopper designated 26, the material flowing down this side has to change direction in entering the spoutl so that greater resistance to the flow of this material is encountered than to down the side 27 of the hopper. Accordingly when an oiisetdischarge spout is employed, the hopper is constructed so that the. axis of its bottom opening lies slightly oliset from the axis of the cone and of the casing, the displacement of thevaxis of the hopper opening being in a direction opposite to that toward whichV the discharge spout is inclined, the amount of such dis-V placement depending on the inclination of the spout, the desired result being to have the axis of the cone and casing pass through the center of the `plane A-A previously described. ll! hen the discharge spout is vertical, then the hopper will be symmetrical with refe ce to the casing, and the axis of the opening i bottoni of the hopper and of the spout will be coincident with each other and with the axis of the cone and casing.

ln some instances, and particularly where coal is being dried, which contains iarge quantities oi" moisture, ell'ect of the hot gases may be supplemented by the indirect drying action of a heating medium, such as steam. For this purpose, the upper section 28 of the drier is conf-dructed with a plurality of tunnels which are placed in vertical alignment, alternate vertical rows of the tunnels being connected to the inlet and outlet ducts for the gases. The tunnels in the row 29 are closed the direct drying at thc side of thc drier illustrated and open at the opposite side, while the tunnels in the row 30 are open at the near end and closed at the far end. In these tunnels are steam pipes 3l which are connected to vertical headers 32, these headers being supplied with steam or other heating medium through header connections 33. The vertical headers 32 may be of the type illustrated in Fig. 7, each header having a plurality of bosses 34, each of which has an inclined seat in which is seated the end ot' a pipe 3G extending through the drier from one side to the other. Tie rods 37 passing 'through the headers and the pipes bind the headers and pipes together, so as to force the ends oi the pipes iirmly against the seats .in the bosses, thus providing a convenient arrangement for assembling and'A disassembling the piping connections without the necessity of employing unions or couplings. With the drier provided with steam pipes, the moist material entering the top of the drier is subjected to a severe drying action as soon as it lenters the chamber, the material receiving heat from the steam pipes and the hot gases and giving up. its moisture which is carried away by the gases and passes out through the tunnels connectedv to the gas outlet duct. This removes a large quantity of the moisture carried by the material so that as the material descends further in the drier, an even distribution can be secured,

After passing through the steam section, the iirst row of ducts, which is a row of discharge chiots, divides the streams flowing down between the vertical rows of ducts in the steam section into two parts, each of these streams descending toward the angular side walls ot' the tunnels or ducts of the next lower row. Owing to the staggered arrangement, these subdivided streams are repeatedly united and subdivided so that a thorough agitation of the descending inaterial is secured. The drying medium lows around the lower edges oi the inlet tunnels and enters'the descending stream, lowing upwardly through the stream to the outlet tunnels of the row next above. Vhen the material has traversed the chamber, it is distributed by the cone and flows out of the chamber into the discharge hopper in the form of a hollow conical stream. By reason of the manner of mounting the cone with reference to the discharge spout, the flow of loo materialthrough the opper and spout is continuous and unilform, so that the A[low at all points in a horizontal section through the column descending through the drier is at a uniform rate. All ot the material `flowing through the drier is thus subjected to a uniform drying action, and packing or building up` ot the material is prevented. Accordingly, the danger oit ignition of the material is avoided, and the material discharge from the drier is ot uniform dryness.

I claim: y

l. In a drier, the combination ot a casing through which the material to be dried liows in a downward direction, means in the casing for subjecting the material to the action ot a heating medium, -a hopper at the botom oli' the casing into which the material vflows, a discharge spout at the lower end oit the hopper, and a distributing device in the casing in the path ot the flowing material, the axis of the casing and of the distributing device being coincident and passing through the center of a plane normal 'to the axis ot the discharge spout at the entrance und thoreo't, while Vthe axis of the hopper lies parallel to but at one side of the casing' axis.

,2. In a drier, the combination of a casing through which the material 'to be dried flows in a downward direction, ine-ans in 'the casing for subjecting the material to the action of a heating medium, a hopper at the bottom ot the casing into which the material flows, a discharge spout at the lower end of the hopper, and a conical distributor in the casing in the path oi the flowing material, the axis of the casing and orn the distributing device being coincident and passing through the center of a plano normal to the axis of the discharge spout at the entrance end thereoi", while the axis ot the hopper lies parallel to but at one side ot the casing" axis.

3. In a drier, the combination oit a caff. ing through which the material to be dri-cd tlows in a downward direction, means in the casing 'for subject-ing the material to the action ot a heating medium, a hopper at the bottoni of the casing into which the material flows, the axis ot the hopper being offset from the axis ot the casing, a discharge spout at the lower end of tl e hopper extending at an angle to the axis thereof and toward the axis of the casing, and a distributing device in the casing in the path of the flowing material, the axis of the distributing device being coincident with that ot the casing and passing throught a plane normal to the axis ot the discharge spout at its entrance end.

4. In a drier, the combination ot a casing through-which the material to be dried JFlows in a downward direction, means in the casing for subjecting the material to the action ot a heating medium, a hopper at the bottoni ot the casing into which thc material flows, a discharge spout at the lower end ot the hopper extending at an angle to the axis thereof, and a distributing cone in the ca =ng in the path of the flowing material, the axis et the cone passing through. the center ot the plane cutting the entire wall of the spout nearest the entrance end thereof and normal to the axis of the spout. y

5. In a drier, a duct of inverted trough shape havingserrated lateral edges, one end of the duct being open, the other closed.

In testimony whereof I aiix my signature.

MICHAEL D, JONES.

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