US2481305A

US2481305A - Apparatus for drying bagasse

Info

Publication number: US2481305A
Application number: US620366A
Authority: US
Inventors: Charles W Fuller
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-10-04
Filing date: 1945-10-04
Publication date: 1949-09-06
Anticipated expiration: 1966-09-06

Description

p 1949- c. w. FULLER 2,481,305

APPARATUS FOR DRYING BAGASSE Filed Oct. 4, 1945 6 Sheets-Sheet l Inventor mar/231% fiM/er Septw 6, 1949. c. W.-FULLER APPARATUS FOR DRYING BAGASSE 6 Sheets-Sheet 2 Filed 001;. 4, 1945 Czar/ea n4 Effer:

Sept. 6, 1949. c w, FULLER 2,481,305

APPARATUS FOR DRYING BAGASSE Filed Oct. 4, 1945 6 Sheets-Sheet 3 Im' utar I (Zara/ e3 7 Fuffe MA My p 1949- c. w. FULLER 2,481,305

APPARATUS FOR DRYING B AGASSE Filed Oct. 4, 1945 6 Shets-Sheet 5 l l l I l Inventor Sept. 6, 1949.

Filed Oct. 4, 1345 C. W. FULLER APPARATUS FOR DRYING BAGASSE 6 Sheets-Sheet 6 Chan/e5 W Fuller 1 N V EN TOR.

Patented sept. G, 19

UNITED STATE S PATENT OFFICE 2,481,305 APPARATUS FOR puma mousse Charles w. Fuller, Clewiston, Fla. Application Dctober 4, 1945, Serial No. 620,366

Claims. l

My invention relates to a process of drying wet fuel and the apparatus employed therefor. The main object of the invention is drying bagasse, that is sugar cane from which the sugar containing juice has been removed, but in general the process is applicable to drying other material to be used for fuel, as for instance wood refuse,

bark, sawdust and the like. In the following the term bagasse generally used herein is meant to include also other material requiring drying before use as fuel, or for any other purpose: 1. e. Celotex is made from bagasse, and bagasse may be used for paper making.

One embodiment of the invention is illustrated more or less diagrammatically in the accompanying drawings, wherein Figure i represents a front elevation of the apparatus used and Figure 2 is a side elevation thereof seen from the right side of Figure l as erected in a building or a drying plant.

Figure 3 is a top plan view of the drying equipment in Figure l and 2.

Figure 3a is a fragmentary plan view of Figure 4 of the tower and the inclined conveyor.

Figure 4 is a vertical section and part elevation of said tower showing the centrifugal mechanism.

Figure 5 is a fragmentary view in larger vertical section of the top portion of the heated drying tower showing the collecting means for moist gases.

Figures 6 and 7 are respectively a top plan view and a side elevation of a revolving cone used in the drying tower.

Figure 8 is a section of the inclined conveyor for feeding raw material into the top of the drying tower, and v Figure 9 is a diagrammatic sketch of the entire apparatus illustrating the progress of the bagasse through the system.

The basic features of the process consist in passing the bagasse, or other wet fuel, by means of a conveyor to the top of a tower through which it falls. In its fall it encounters a. strong current of flue gas or pre-heated air moving in the opposite direction or upwardly in the tower. The tower contains a number of baflles soplaced as to break the fall of the material into a series of cascades through which the hot gas passes, being drawn out of the top by means of an exterior exhauster fan. Part of the flnes'are also removed by this fan and later separated by another exterior fan as will be herein described. The material passing to the bottom of the tower is fed to a hammer mill or other similar device, if it is necessary to further reduce the size of the particles, and to another fan which also draws a strong current of hot flue gas or preheated air through the hammer mill and discharges the gas and material to another cyclone separator and thence to another conveyor for delivery into the furnaces.

In the diflerent figures, the same numerals correspond to the some details. Numeral l represents the upper strand of an endless supply conveyor which is used to bring the bagasse, or other wet material, from the mills to the furnace 5 with boilers l where the drying plant is located. The furnace Bis usually arranged in batteries and the conveyor passes over the whole battery. It first passes the furnace or furnaces on the upper strand 1 in the direction of arrow X, Figure 1, then the material is dropped onto the lower strand 2 of the conveyor, running oppositely, in direction of arrow Y, via a gate lb 2 subsequently dropped through the

gates

3, 3 into chutes d, 6 which deliver the hagasse directly into the

furnace

5, 5. In this case two furnaces have been shown but there may be any number, one, two, or three furnaces to a boiler.

In order to dry the material it is carried past the

gates

3, 3, which then must be closed and to gate 6 which when opened drops the material thru chute 6a which delivers it directly onto the heated inclined conveyor or elevator 'l which is 3 operated by the motor 48. This elevator delivers the material at the top of the drying tower 3i through a chute 50.

In the drying tower at is shown a series of baflles consisting o1 revolving cones 32 carried by supporting spiders, and of inverted stationary cones 31. The revolving cones and spiders are supported on a. shaft 33 at top and bottom and passing up through the centerof the tower 3i and may be revolved at any predetermined speed in order to delay the e of the bagasse, break up any adhering lumps, and permit more complete contact with the upward current of hot gases, thereby removing more moisture.

The upper surface of the revolving cones 32, see Figure 6, I, carries curved vanes 32a secured on the upper surface of each cone which is attached'to the axial shaft 33 carried in a suitable bearing 35 here shown atthe top of the tower 3| and driven by bevel gears enclosed in the housing 34 furnishing needed lubrication for the gears. One or more lower bearings 36 are provided for the lower end of the shaft 33, held by horizontal arms in the tower, see Figure 4, to prevent vibration. .55 Between each'two revolving cones 32 is provided a fixed inverted baflle cone 31, open top and bottom, see Figure 4, and made of sheet metal. These baille cones serve to retard the downward passage of the bagasse or other material thru the tower. Several circular rows of perforations 31a are shown to permit the rising current of drying gas to pass and clean the cone surface.

The hot fiue gases to heat the drying tower 3| are drawn from the breeching l0, through the pipes and i2 by means of the exhauster fan |4 actuated by motor |4a, also drawing the ases from the top of the dryer through pipe IS. The moisture laden gases and fines are delivered by pipe l to cyclone separator It. (See Figures 1 and 2.)

The inclined conveyor or elevator], best seen in Figures 3, 4 and 8 is carried on a pair of parallel channel irons 40 reaching from beneath chute 6a of conveyor 2 to the upper end of the drying tower 3|, where the ends are firmly anchored and between and beneath said channels is secured a perforated floor plate 4|. At each end of the pair of channels is furnished a transverse shaft 42 for sprocket wheels 43 over which run the endless elevator chains connected bytransverse slats 44 of hardwood or the like. These slats slide up along the floor plate 4| on the upper run or strand carrying the raw material with it, while on the lower run they are a supported on longitudinal angle bars 45 suitably suspended from the channel bars 40. A nest of steam pipes 46 for supplying heat to dry the material is supported under the angle bars 45. The conveyor chain 44a is run'by a belt or chain drive, a sprocket 41 which is carried on the end of the upper shaft 42 and actuated by a motor 48 with a speed reducer 48a.

The material carried up by the inclined conveyor or elevator 1, is dumped from the upper run or strand thereof into a fixed chute 50, inclined about 60 from the horizontal and then dumped over the top cone 32 in the drying tower 3|. This chute 50 has a flaring upper skirt 50a, until it reaches the side of the tower where its lower portion tapers and curves as seen in Figures 4 and 5. Opposite the same is shown a fixed baffle plate or guide 5| for directing the rising gases and moisture from the material to the exhauster hood |3a to be led 011 from the tower 3| thru pipe i3 aided by the exhauster fan |4.

By means of an intermediary shaft 52 and

chain drives

53 and 54 power is transferred from motor 48 and conveyor shaft 42 to the bevel gear shaft 35a, whereby the axial tower shaft 33 with its several revolving cones 32 is rotated.

All the heavier material which falls to the bot tom of the tower after having passed all baflies in tower 3| is fed into the hammer mill l8 if further disintegration is necessary. However, if any treatment by hammer mill I8 is unnecessary, the material goes directly to the fan 20 which also draws hot gases through pipes l9 and Ho, from pipes II and 2. The material from fan 20 is then delivered through pipe 2| to the cyclone separator 22. More moisture is thus extracted from the Bagasse by this process. All pipes are exteriorly heat insulated to prevent cooling of the hot gases and condensation of the moisture carried by them.

A horizontal conveyor 23 of any suitable construction driven by motor 23a is provided for passing the coarse material and/or the fines delivered thereto via feed pipes ill from the separators l6 and 22 to feed the material through 21 and 21a to the exhauster fan 20 which delivers 4 the gates 24 to feeders 25 either to the conveyor I or directly by chutes 26 and 4 to the furnaces 5. If desired, the coarse material and fines may be delivered directly to bags (not shown) through branch pipes 52 communicative with the pipes 60 by means of suitable gates 64.

Other pipes 21 and 21a are provided to conduct the fines, separated by the cyclone separators l6 and 22. Said pipes furnish an exit for the dried fines, from the tops of the separators to the exhauster fan 28, Figures 1 and 2, which delivers them through the pipe 29 to the burner 30 where fresh air is supplied for the combustion of the fines.

The operation of the plant for drying bagasse, or other fuel material is the following, special reference being had to Figure 9:

The bagasse enters from the sugar mill upon the conveyor strand I, which passes in front of one or more boilers to some point beyond the furnace where it is dropped to the lower strand 2 via gate lb, whence it is usually fed by means of the gates 3 through the chute 4 direct into the furnace 5. This method of operation is followed until the furnacesare heated and hot gases passing out through the stack.

The gates 3 are then gradually closed and the gate at 6 opened to permit the bagasse to fall into the feeder chute 6a and onto the inclined conveyor or elevator I which may be heated by steam pipes or hot gases. This elevator is operated by the motor 48 and delivers the bagasse near the top of the tower 3| onto the chute 50.

When the bagasse enters the top of the drying tower 3| and falls down through the same it encounters a strong upward current of hot flue gases, either from the breeching Iii leading to the chimney, or from the chimney direct if this is found to be easier. These hot gases are carried into the tower 3| by pipes II and I2 by means of the exhauster fan l4 drawing the gas from the top through pipe i3. The moisture laden gas and some fines carried off by the suction of the fan H are delivered by pipe |5 to the separator It.

In passing downward through the tower 3| the bagasse encounters a series of revolving cones 32, which can be revolved as already described, and baflie cones 3'! which are fixed to the sides of the tower 3|. The revolving cones 32, with vanes 32a on the top are arranged to give the bagasse a centrifugal motion as it is thrown offducted via the branch |9c of the pipe l9 directly to the hammermill iii to completely break up the coarse material in order to extract all moisture. If desired, the coarse material may be conducted through pipe' i9 directly to the exhauster fan 20 to be blown through pipe.2| up to the cyclone separator 22.

From the separators l6 and 22, the coarse and fine material may be led through pipe 60 onto the conveyor 23 and from the latter through gate 24 and feeders 25 to be delivered onto the conveyor for a repetition of the cycle mentioned hereinabove. If desired, the material may be ldvia gate 64 to the conduits s2 and thence to bags (not shown). Also, if desired, the material may be led from the feeders 25 by chutes 4 and 26 directly to the furnace 5.

Alternately, the fines separated by the cyclone separators may be conducted through the pipes them to the burner 39 where fresh air is supplied for the combustion of the fines.

It is to be understood that the invention as here disclosed is not limited to the details here described but that the same may be varied without departing from the spirit of the invention as defined by the subjoined claims. So for instance the drive of shaft 33 for the revolving cones 32 may be applied from the bottom thereof instead of the top. Likewise a fan may be used for the top, said tower having inner and outer bellies alternating from the top thereof, providing a tortuous passage between the baffles through which the material is dropped from the top of the tower, the inner bafiles comprising cones mounted for rotation and spaced from the wall of the tower, means for rotating said cones, said cones sloping outwardly, the outer baliles comprising inverted frusto-conical members extending from driving air upwards thru the tower instead of exhausting the gases by a fan.

1. In an apparatus for drying wet material of the hagasse type for use as a. fuel or in the manufacture of board and paper, comprising a drytower consisting of a vertical tubular cas ing, means for discharging the bagasse into the upper portion of the tower, means for drawing hot air and gases upwardly through the tower from the bottom thereof and discharging the same at the top, a series of spaced alternating stationary and revolving baflies arranged in said casing and comprising inner conical baflles, a shaft rotatably mounted axially through the cas ing and to which said inner baflies are secured, means for rotating the shaft, said inner baflies having their peripheral edges spaced from the wall of the casing, outer frusto-conical baflies arranged alternately between the inner baflles and extending from said wall inwardly beneath the peripheral edges of the inner bailies in inverted position inclined inwardly with their small ends open at the bottom to receive the material from the inner baffies in cascades and dropping downwardly through the tower from one cone to the other, said inner bailies having curved vanes thereon to give the bagasse a centrifugal motion as it is thrown ofi from the revolving bames, said outer baffles receiving the material from the inner bames and discharging the same at the bottom upon the inner bames therebeneath, said hot air and gases passing upwardly in a tortuous path at the inside of the outer bailies and outwardly of the inner baffles within the casing and prevented from passing between the outer battles and the casing, means to prevent adherence of the material upon the surfaces of the outer baifies, the fines passing off with the heated air and gases at the top, a grinder receiving the material at the bottom of the tower, means for exhausting and conveying said material therefrom, means for supplying hot air and gases to said grinder and latter means, means for conveying the dried material from said latter means for discharge to the furnace or storage, and a. separator adapted to receive the fines together with the hot air and gases from the top of the tower for discharge to a furnace and also adapted to receive the bagasse from the conveyor leading from the bottom of the tower after passing through the grinder for discharge to the furnace or storage.

2. The combination with a. furnace of-an apparatusfor drying wet material of the bagasse type for use as a fuel, for making paper or the like, said apparatus comprising a drying tower, a separator, a grinder, means for transferring said material into said apparatus from a source of supply, said transferring means consisting of a. feeder for the drying tower for conveying the material into the top thereof, means for drawing a current of hot air and gases from the breeching of the furnace upwardly through the tower from the bottom thereof for discharge at the wall of the tower and sloping inwardly and downwardly beneath the inner cones and having restricted discharge openings at the bottom beneath the outer portions of the inner cones to provide a tortuous space for passage of the material through the tower between the bafiies for exposure to the heated air and gases passing upwardly through the tower, means for dislodging and preventing adherence of the material to the baffles, a grinder at the bottom of the tower to receive the material, means extending from the grinder for conveying the material from the grinder, means for supplying heated air and gases to the latter means for additionally drying the material, a separator connected to the means for drawing the hot air and gases upwardly through the tower to the top thereof for receiving the fines from thematerial therewith, and means for discharging and feeding the fines and other bagasse material to the furnace or for conveyance to storage. a

3. The combination with a furnace of an appa ratus for drying wet material of the bagasse type for use as a fuel, for making Celotex, paper or the like, said apparatus comprising a drying tower arranged vertically and provided with a tubular casing having a series of alternately arranged stationary and revolving baffles therein in spaced relation, said stationary bailies extending from the wall of the tower inwardly and open at the bottom to receive the material from the revolving bailies and discharge onto the same, means for revolving said revolving bafiies, said baflles providing a tortuous passage for material dropping through the tower, means for transferring said material from a sugar mill or other source of supply to and over the furnace, a conveyor extending from said transferring means to the top of the tower for discharge thereinto, a chute in the tower receiving the material from the conveyor for discharge onto the baffles, means for supplying heated air and gases in a stream to the bottom of the tower and upwardly therethrough, means for discharging said heated air and gases at the top of the tower after passing through the material dropping between the baflles to the bottom thereof and for conveying the fines from the material a separator connected to the latter means for receiving said hot air and gases and fines therefrom, means for discharging said fines into the furnace, means at the lower end of the tower for conveying the dried material therefrom and conveying the same upwardly for discharge to the separator, into the combustion chamber of the furnace or to storage.

4. In combination with a furnace of an apparatus for drying bagasse comprising a drying tower, a separator, means for initially conveying the bagasse from a source ofsupply to the furnace until heated andhot gases pass out of the breeching of the furnace to the stack thereof, means for conveying the material from the latter means to the top of the tower, a series of alternating stationary and revolving baflles arranged in the same together with the fines from the bagasse to the separator for subsequent delivery to the furnace, and means for conveying the dried bagasse from the bottom of the tower for feeding into the combustion chamber of the furnace or to storage.

5. In combination with a furnace of an apparatus for drying bagasse comprising a drying tower, a separator, means for initially conveying the bagasse from a source of supply to the furnace until heated and hot gases pass out of the breeching of the furnace to the stack thereof, means for conveying the material from the latter means to the top of the tower, a series of alternating stationary and revolving baiiles arranged in the tower, said tower comprising a tubular casing, the stationary bailies extending inwardly from the casing to prevent the passage of hot air and gases therebetween, said bagasse adapted to cascade between the baiiies in dropping downwardly through theftower, means for supplying heated air and gases to the bottom of the tower and cnnected to the breeching of the furnace, means for causing a rising countercurrent of hot air and gases upwardly through the tower for drying the descending stream of bagasse downwardly therein between the battles and for discharging the same together with the fines from the bagasse to the separator for subsequent delivery to the furnace, a hammer mill connected to the bottom of the tower to receive the bagasse dropping therethrough, means connected to the hammer mill receiving a supply of hot air and gases from the same source as the tower, a suction fan for drawing said hot air and gases through said hammer mill and for discharging and elevating the partially dried wet material to said separator for removing moist gases therefrom and delivering the same to the separator for subsequent discharge to the furnace or to storage at the transferring means, and means for discharging the fines from the separator to the combustion chamber of the furnace.

CHARLES W. FULLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 485,355 Rathman Nov. 1, 1892 762,344 Parsons June 14, 1904 762,345 Parsons June 14, 1904 803,424 Matcham Oct. 31, 1905 1,383,921 Fredel July 5, 1921 1,653,332 Baechler Dec. 20, 1927 1,718,104 Baechler June 18, 1929 1,779,536 Goodell Oct. 28, 1930 1,809,819 Caller June 16, 1931 1,817,228 Bliss Aug. 4, 1931 1,933,254 Goodell Oct, 31, 1933 2,049,071 McCormick July 28, 1936 2,102,427 Lloyd et al. Dec. 14, 1937 2,171,535 Berg et al Sept. 5, 1939 2,271,157 Badenhausen Jan. 27, 1942 FOREIGN PATENTS Number Country Date 166,517 Great Britain June 11, 1921 528,407 France Aug. 16, 1921