US2027977A - Drier - Google Patents

Description

Jan. 14, 1936.

' vH. F. HE'BLEY ET AL Filed Aug. 9, '19:3

5 Sheets-Sheet l 1 7.27 .VEN/DF E HENE yf." Het-7L E Y,

KLHHE PRINS:

Jan. 14, 1936. H. F. HEBLEY ETAL 3 Sheets-Sheetl 2 Filed Aug. 9, i 1933 ma E if I7! I H 7 77,

lnx/Enf: F E

v HEZJL E HHS PEINE.

Jan. 14, 1936. H. F. HEBLEY ETAL.

DRIER 'l Filed Aug. 9. 1933 3 Shs:ei',s-Shee'tl 5 M555 FEL/V5'.

.Z l E..

Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE Damn.

Henry F. Hebley and Klaas Prins, Chicago, lll. Application August 9, 1933, Serial No. 684,306

5 Claims. t (Cl. 34-4) This invention relates to driers adapted particularly for the drying of comparatively flne coal or other granulated materials.

The invention is particularly adaptable for the eicient, economical and rapid drying of comparatively ne coal after the impurities have been separated therefrom ,by a wet washing process.

An important object of the invention is to provide -an arrangement and procedure by .which the material to be dried is conveyed by perforated buckets through a fixed orbit and the material subjected to a preliminary step of water removal by the application thereto of hot gas under pressure which will exert pressure against the material in the buckets to squeeze water therefrom'but without sufficient heating to vaporize all of the water.

A further object of the invention is to subject the material, after pressing and entrainment of water therefrom during the first step by the hot gas under pressure, to a second treatment step during which the hot gas is forced in reverse direction through the material in the buckets to cause loosening, aeration, and heating and vaporization of moisture, and then subjecting the material to a iinal passage therethrough of the hot gas under pressure for final removal of the moisture and thorough drying of the material.

Another object is to so apply the drying gas to the material that it will receive the least.

amount of heat during the initial step when water is pressed and entrained therefrom and so that the temperature will increase and be greatest during the nal application of the drying gas tothe material.

A further object is to provide simple and efcient means for guiding the iiow of the drying gas in its various directions through the material in the buckets, and to provide eiiicient means for collecting the removed moisture and conducting it from the machine.

The above enumerated and other important features of the invention are shown incorporated in the structure disclosed on the accompanying drawings, in which drawings Figure 1 is an end elevation;

Figure 2 is a side elevation partly in section on plane II--II Figure 3;

Figure 3 is a section on plane III- HI Figure 2;

Figure 4 is an enlarged section through the bucket structure on planevIII--III Figure 2; and

Figure 5 is a section on plane V-'V Figure 4.

The structure shown comprises a generally cylindrical housing wall I having annular end' walls 2 and 3, the housing structure being mounted on a suitable foundation 4. `Secured within and closing the end walls 2 and 3 are the circular bearing frames 5' and 6 having the bearing hubs 1. Journalled in the hubs are bearing sleeves 9 to whose outer ends are secured driving lmembers Il which may be gears or pulleys. Extending through and supported bythe bearing sleeves is a shaft ID which is held against rotary or axial movement by a support I' (Figure 2) to which it is secured. Partition walls II and I2 extend longitudinally between the bearing frames and 6 and are adjustably supported by and secured to. the shaft by suitable clamping brackets I3.

Secured to the inner ends of the bushings 8 are the circular end plates or discs I4 and I5 respectively, these plates being concentric with the bearing frames 5 and 6 and the shaft I0, and being substantially ofthe same diameter as ,the bearing frames. Between the end plates I4 and I5 and secured thereto is an assembly of a series of annular bucket structures for rotating with the end plates when powerY is applied to the driving members 9. Any suitable means may. be provided for driving the members 9.

As shown, a motor I6 drives a shaft I'I having pulleys I8 thereon 'connected by' belts I9 with the driving members 9.

Each bucket or conveyor unit C comprises supporting side walls and 2| in the form of flat annular sheet metal plates between which the bucket structures B are secured. Extending between and secured to the side walls 20 and y 2| at regularly spaced intervals areV the diag- 2| for receiving and aligning the ends of a perforated plate 26 bent to U-shape to define the bottom of a bucket structure, the plates 26 being held against the frames by arcuate plates or frames 21 preferably detachably secured to the side walls 20 and 2l. -The plate 26 may be perforated metal, or screen material, or Sii-'called wedge wire screen material. The

upper edge of each screen plate terminates at and abuts against the upper cross wall 23 deflning the bucket compartment, the walls 23 extending forward of the plates 20 and 2| with their outer ends forming a continuation of the upper` side of the perforated bucket bottom 26 and the inner ends 23' being preferably deflected upwardly at a comparatively slight angle away from the bucket bottom plate 26.

The lower side of each bucket bottom plate is spaced a distance away from the cross wall 23 directly below, and the cross wall at its outer end 29 is deflected to extend circumferentially in alignment with the outer edges of the side walls 20 and 2| and to form a seat for engagement by the end of the lower side wall of the bucket bottom plate 26, the space 3D between the bucket bottom and the cross plate therebelow receiving moisture dropping through the bucket bottom perforations. y

Steel bars 3| are shown extended between the side walls 2|) and 2| and welded to the outer ends of the cross walls 23 to present a sharp, scooping edge along the lower edge of the bucket, so that the material to be cleaned may be scooped into the buckets from a suitable hopper structure which will be described in detail later.

The housing wall has the longitudinal opening 32 in its side through which extend the diagonal wall 33 and the vertical wall 34 of the hopper H through which material is fed to the bucket. units. The wall 33 extends a distance -circumferentially around the bucket structure and terminates at the discharge hop-A per I from which an exhaust gas duct 35 extends laterally. .Above this exhaust duct is the inlet duct 36 for the hot drying gas which may be delivered from suitable heating and pressure producing means. (not shown). The ducts 35 and 36 extend through the longitudinal opening 31 in the housing wall and terminate adjacent to the periphery of the bucket drum structure. The top of the housing the top of the duct 36, and the sheet hopper wall 34 dene the chamber or space 38 above the revolving bucket drum structure, the lower end of the hopper wall 34 terminating close to the periphery of the bucket drum structure.

'I'he partition walls and I2 extend to the inner periphery of the annular-bucket drum structure and denne therewith the space 39 into which the heated gas isdischarged from the inlet 36. A screen 40 extends from the lower wall of the inlet 36 and circumferentially adjacent to the outer periphery of the bucket 'drum structure and terminates near the outer end of the partition wall this screen serving to prevent escape of the material from the buckets but permitting the flow of hot gas. therethrough. Another screen 4| extends upwardly a distance from the lower edge of the hopper wall 34 and adjacent to the outer periphery of the bucket drum structure, this screen preventing escape of material from the bucket but permitting the passage of hot gas therethrough. The partition walls and 2 and the rotary annular drum y, structure define a second chamber or space 42 for the passage of the drying gas, the partition walls I2 terminating near the bottom of the gas inlet 36.

A baille Wall or plate 43 extends from the end'of the partition wall into the space 39 and adjacent to. the inner periphery of the bucket drum structure and a baille plate 44 extends from the lower end of the partition wall |2 into thespace 42'adjacent to the inner periphery of the drum structure. The drum structure rotates in counter-clockwise direction (Fig. 3) and the inner ends of the crosswalls 23 of the bucket compartments trail over and engage with the baille walls 43 and 44 so that direct communication from the space 39 to the space 42 is prevented and also' communication between the space 42 and the inlet duct 36. To afford greater sealing or baiiling area, the crosswalls 23 have the deiiected inner ends 45.

Extending longitudinally within the space 42 is a tier of drain plates 46 which may be supported between end walls or plates 41. 'Ihe walls 41 terminate near the inner periphery of the revolving drum structure and at a point between the hoppers H and I and above a water drain spout 48 extending from the wall 33. The drain plates 46 are inclined slightly downwardly toward the right (Fig. 3) and underlap each other and are spaced apart to leave passageways for the flow of the drying gas, the lower drain plate being located to discharge above the drain spout 48.

'Ihe various spaces 39 are connected together by drain ports 49 in the side walls 2|) and 2|, and the end-plates |4 and I5 of the drum structure have the ports 50 communicating with the adjacent spaces 30 so that any water collected in the spaces 30 may iiow from space to space and eventually through the ports 50 onto the shell 33 down which the water will flow to the discharge spout 48.

Describing now the operation, the bucket drum structure rotates in counter-clockwise direction (Fig. 3) so that, as thebucket compartments are carried past the mouth of the feed hopper H, the Wet material to be dried is scooped up into the buckets to be carried around to the discharge hopper 1. Any free water in the material in the hopper H will iiow down the shell 33 to the discharge spout 48 and free water in the material scooped up in the buckets can ow through the perforated bucket bottoms onto the crosswalls 23 to flow down from the inner ends of these walls or ow into the drain ports 49. `As the filled buckets pass .the lower edge of the hopper wall 34 and travel past the baille screen 4|, the material is leveled oil? in the buckets, and during the travel of the lled buckets along the space 42, the material therein is subjected to the hot gas under pressure supplied through the inlet 36. The gas first ows from theinlet 36 through the screen 46 and through the lled buckets as they pass the inlets, the gas entering the chamber 39 and then iiowing in reverse direction through the iilled buckets and the screen 48 and into the space 38, from which space the gas flows through the material of the buckets into the space 42. The baille wall 43 prevents direct flow oi gas from the chamber 39 tothe chamber 42 and diverts the iiow iii-st through the chamber 38 from which the gas flows downwardly through the filled buckets. The gas being under pressure it will exert pressure against the material in the buckets and will squeeze and entrain moisture therefrom, the

entrained water dropping down in the chamber 42 to be caught by the deiiector plates 46 and diverted to the discharge spout 48, the gas ilow continuing through the spaces between the plates and through the empty buckets at the bottom of the drum structures and out through the discharge or exhaust duct 35. The incomlng hot gas, after flowing twice through thermaterial in the buckets before reaching the llezd baskets -passina the., member. #2r-.hastings con..- sidereble .off.'.tsttemnereturei:S01 .,that-. here :will he. ...little evaporation during .therfirstrfstep of Squeezinsr. he:.moisturefslitwot the l the; .hot sas., through A etti/:andi fromfthe spacer; 39 removes considerable .of;. ;the=.-;moisture .from l the material,;.and ,.fafter the bucketsjt fpass thebailiev43,ithe material thereiniis, subjected to, the'. hotter4 gas i flowing vtheretlrirough' .from the space 39; in outward direction. This :reversed flow` of the gasthrough the material from the bottom to the top thereof will destroy the compressing eiect resulting from the squeezing treatment and the material is loosened up so that the hot gas can readily iiow therethrough for heating and vaporizing of the moisture, the

screen 40 preventing escape of the material from the bucket.. Now, as the buckets reach and 4travel past the inlet 35, the material is subjected to the hottest temperature `and the direction of iiow is again reversed, the hot gas owing inwardly toward the bottoms of the buckets and through the material for final vaporization of the moisture and drying of the material. After leaving the inlet 36 the buckets travel'a short distance along the apron 5I and then, as the uncovered buckets travel along the hopper I, lthe contents thereof are discharged into the hopper. The gas leaving the space t2 flows through the buckets as they are discharging into the hopper, and any pressure left in the gas will assist in loosening the material for complete discharge from the buckets and any heat 4left in the'gas will be conveyed to the .discharged coal or material.

When the material issubjected to the rst or squeezing treatment, it is heated but not sufliciently for any material vaporization of the moisture. The 'heat from the hot gas in space 39 is then added to this preliminary heating so that vaporization quickly and efliciently results, and the hot material, when finally subjected to the hottest temperature at the inlet 36, will be quickly deprived of its moisture and fully dried. The drying scheme is thus on ythe -counteriow principle, that is, the hottest material comes in contact with the hottest gases. The material is carried through an orbit in one direction (counter-clockwise, Fig. 3), while the gas flow is in the opposite or clockwise direction. The material is carried through four (4) treatment zones, in the first of which it is subjected to the squeezing and moisture entrainment action, the treatment in the second zone reversing the flow of the gas through the buckets to loosen up the material for eective vaporization of the moisture, the treatment in the third zone involving reversal of the flow through the buckets and the application of the high temperature to the material for nal drying, and the fourth step being the discharge of the dried material into the discharge hopper. The water squeezed out of the material during the first treatment thereof and which drops down onto the louvregfor deector plates 46 is discharged from the'bottom vplate onto the crosswalls 23 from which it may overflow to pass through the perforated bucket bottoms and out through the discharge spout 48,- or ow through the ports .49 to eventually reach the discharge spout in fa ,manner already explained.

The apparatus and treatment shown and de- ,may .be madefshallowenor.

orjother granulated material of about one-half rial thefbuckets,maytbe.modifiedaaccordingly,.and of the: most eihcient The,drying llxsnedium.v may enhotaireunder cribed is very efficient for the drying of coal' gllsliftbe,usadas` Forsdryingiother types fof .matepressure Aor some suitable'fgas@suchv as'ilue gas, :f

andundertv certain l,condititms steam may be used, or flue gas and steam.- i

- to carrythe lled buckets through a fixed path,

means for applying pressure to the material in said drums during the rst part of said path whereby to squeeze moisture out of the material, and means for forcing hotvdrying mediumunder pressure through the buckets and the material during the latter part of said path.

2. In apparatus of the class described, the

combination of a-rotary support having buckets thereon for receiving material to be dried, means for rotating said support `to carry the buckets through a fixed path, means for feeding material to said buckets at one endfof said path during travel of the buckets, means operative at the forepart of said path for applying pressure to the material in the buckets in a direction to press moisture therefrom for partial drying of the `material, means for blowing hot drying medium through the buckets when travelling through the latter part of said path and in reverse direction for loosening the compressed material for intimate application o f the heat thereto and evaporation of the remaining moisture therefrom, and means for discharging the dried material from the buckets at the end of said path.

3. In apparatus of the class described, the combination of a rotary drum having peripheral substantially radially extending depressions dried, means for rotating said drum to carry said buckets through a fixed path, means at one end of said path for delivering the material to the buckets during travel thereof, stationary means within said drum forming with said drum an inlet chamber and an outlet chamber, a drying medium inlet located outside of said drum path substantially opposite the material feeding forming buckets for receiving material to be` chamber compressing the material in the buckets adjacent to said chamber for pressing moisture out of the material, the ilow of the'heating medium from said inlet chamber through the buckets serving to loosen the compressed material for effective evaporation of moisture therefrom, the heating medium flowing from said inlet through said buckets serving to finally drythe material therein. and means for receiving the dried material from the buckets.

4. In an apparatus of the class described, the combination of a rotary drum having peripheral substantially radially extending depressions with perforated bottoms to form buckets, means for rotating said drum to carry said buckets through a ilxed drying path, means at the beginning of said path for feeding to the drums the material to be dried, means for directing drying medium under pressure to iiow inwardly through the buckets at the end of said drying path and then outwardly through the buckets at an intermediate part of said path Vand then inwardly through the buckets at the forepart of said path, the heat of the drying medium at the forepart of said path being insuiilcient to vaporize the moisture in the material but the pressure being sufilcient to cause compression of the material in the buckets and squeezing of moisture therefrom, the outward now of the heating medium through the buckets at the intermediate part of said path loosening up the compressed material for eiilcient-evaporation of moisture therefrom,

`the heating medium flow through the buckets at the end of said path ilnally drying the material, and means for receiving the dried material from the buckets Vafter passage thereof through said drying path.

5. In apparatus of the class described, the

combination of a rotary drum having peripheral depressions forming buckets for receiving material to be dried, means for rotating said drum to carry said buckets through a fixed path, means at one side of said path for delivering the material to the buckets, a discharge outlet at the bottom of said path, a drying medium inlet at the side of said path above said discharge outlet;y a stationary partition within said drum extending from lthe top thereof to a point between said discharge outlet and said drying medium` inlet and dividing said drum into an inlet chamber and an outlet chamber, said drying medium inlet serving to direct hot drying iluid under pressure through the adjacent buckets and material therein and into said inlet chamber, said partition deflecting the drying medium to'ilow outwardly through the buckets above said drying medium inlet, a duct for .receiving the drying medium from said inlet chamber and directing it to iiow downwardly through' the buckets at the top of said outlet chamber and through said chamber, the drying medium being directed by the partition to flow through the buckets at the bottom of the path and out through said discharge outlet, the pressure of the drying medium flowing through thebuckets at the top of the outlet chamber being sufficient to compress the wet material within the buckets to squeeze and entrain water therefrom, means for collecting the water and discharging it from said drum, the pressure of the drying medium when flowing through the buckets at the bottom of said path serving to loosen the dried material from the buckets for discharge thereof into the discharge outlet.

HENRY F. HEBLEY. KLAAS PRINS.

Images