US1513465A - Waste-heat drier - Google Patents

Description

M. J. Il lDE WASTE HEAT DRIER FiledvMay l0. 1923 2 Sheets-Sheet l Chrome? 1,513,465 M. J. LIDE WASTE HEAT DRIER Filed MayA 1o.

1923 2 Sheets-Sheet 2 @Huang y Patented @et 28, 1924.

MARTIN J. LIEBE, 0F BIRMINGHAM, ALABAMA.

WASTE-HEAT DRIER. 1

Application led May l0, 1923.

To all w/'Lom t may concern.'

Be it known that I, MARTIN J. Linn, a citizen of the United States of America, residing at Birmingham, in the county of Jefferson and State of Alabama, have invented certain new and useful mprovements in VasteHeat Driers7 of which the following is a specification.

My invention relates to a new and improved apparatus for utilizing the waste heat from bo-ilers or other available sources for the purpose of eiticiently drying various products suc-h as washed coal preparatory to pulverizing lthe same in a suitable mill to produce pulverized fuel.

My invention contemplates the provision of a casing into which the gases carrying the waste heat are forced under pressure and caused` to pass through grates carrying the product to be dried.

My invention further contemplates the provision of novel and positive means for accomplishing the feed of the product to be dried transversely across superposed grates, causing it to How in a comparatively thin sheet in a circuitous path back and forth across the drier casing and thus to be acted on a number of -times by the gases passing through the casing.

A further feature of my invention consists in the novel arrangement of chutes at the ends of each grate section which utilize the stack to seal the-connecting passage between grates, thereby preventing the short oircuiting of the gases through said passages and forcing the gases to pass upwardly through the stock in the grates.

My invention also contemplates a special design of grate adapted to permit the free flow of hot gases through the grates to dry the product resting thereon while prevent ing the escape of the product between the gratesections which are relatively movable to positively feed the product resting thereon.

My invention further comprises the novel details of construction and arrangements of parts, which in their preferred embodiment only are illustrated in the accompanying drawings and described in detail in the following specification. f

According to the drawings Fig. 1 is a vertical section through the drier casing proper, the discharge end of the chute and mill being shown in elevation.`

Serial No. 637,982.

F ig. 2 is a side elevation of a portion of the drier casing showing the operating mechanism for the two lower sets of grates.

F ig. 3 is an end elevation of F ig. 2.

Fig. 4 is a cross-section through a standard grate segment; and

F ig. 5 is a cross-section through a portionl gases under the requisite pressure through' a pipe a into the hopper botto-m 5 of the cleaner casing 6. The gases enter abovethe.-

angle of repose of the dried stock 7 in the hopper and below the low'estdrying grate. The wet stock enters through an inlet chute 8 at one side of the top 9 of the casing and is delivered by a feed chute 10 to the top grate. The grates are preferably of a type adapted to permit the gases to pass freely upwardly .therethrough tothe stock and also to be relatively movable for the purpose of positively feeding the stock transversely of the drier.

In the preferred embodiment of stock drying and feeding grate shown, each grate is composed of a horizontal row of similar rocking grate segmentsull, all being duplt-` cates and each comprising a top or stock supporting face 12 provided with closely associated transverse narrow ports or slots 13 extending from the axial side of the upper segment face to itsfree outer edge. From the latter edge extends downwardly a curved guard 14 which subtends an arc of oscilla' tion, that shown being approximately 90 and is` connected to or cast integral with supporting webs or walls 15 that are lntegral with or connected to t-he axial body portion 11 of the grate segment. Eachrsegment is provided with end trunnions 16 which project through openings inthe side walls 17 of the casing and are mounted in suitable bearings 18 attached to the outer face of said side walls. The horizontal tier of segments composing each grate are so closely associated that as a grate segment is rocked about its tru-unions to swing its stock supporting surface 12 from horizontal to vertical position, its respective guard portion la maintains so close a clearance with the segment acont thereto that no appiev ciable amount of stock will fall through the grates, it being my desire to have the stock fed back and forth across the casing by the grates so as to subject it in the most effective manner to the drying action of the gases. rlhe grate segments are operated by the mechanism hereinafter described, the segments composing each grate being connected in alternate groups and the uni-ts of each group being moved oppositely to those in the other group. The chute 10 stands in such close juxtaposition to the guard 111C of the adjacent grate segment that the stock will not fall between the chute and segment. The wet stock having been fed across the upper grate falls into a chute. 19 having its bottom juxtaposed to the adjacent guard of the next lower grate, it being noted that the guards are disposed towards the chute in this grate. riihe stock, having been fed across the secondv grate, is discharged into a chute 2O and delivered to the next lower gra-te, which in turn delivered it to a chute 21. rlhe chute 21 delivers it to the lowest grate, which in turn delivers it to a chute A single grate segment is disposed at lthe bot-tom of this chute 22 and this segment, as well as the adjacent segment to each of the chutes above it, acts to support the stock in such position in the chute as to seal the latter against the by-passing of gases therethrough. This bottom grate segment is connected up for oscillation with one of the segments of the lower grate. rlhe waste heat bearing gases, after being forced up through the grates and the stock thereon, escape through the outlet 23 to a stack or other suitable point of disposal and the dried stock is fed by a chute 2a, leading from the hopper 5, to a grinding or pulverizing mill 25. which is preferably of the ball type and which will act to grind the stock to the requisite pulverized form. for discharge by air blast through the pipe 26, leading from the top of the mill, to any suitable point of consumption.

While it is to be understood that the grates` may be operated by any suitable mechanism which will cause the segments to feed the stock positively across the drier, l have illustrated in Figs. 2 and 3 which I new consider the preferred mechanism for this purpose. Here l show the alternate segment trunnions of the two lower grates having cranks 27, keyed thereto and connected to a comino-n rocker bar 28 for each grate, these rocker bars for the two grates in question being in turn connected by links 29 to a common operating rod 30 connected to a crank disk 31. This disk is mounted on a shaft 32 suitably journaled in bracket bearings 33 attached to the vertical wall 3l; of the drier casing. The shaft 32 carries on its other end a. crank disk 312L which, by means of a rod 3ft, links 29, rocker bars 28a and cranks 27u, all disposed on the opposite side of the drier from thesimilarly numbered parts first described, will serve operate the segments not shown connected to bars 23 in Fig. 2. rlhe crank pins on the disks 31 and 312L are set 180O apart thus giv ing the adjacent segments in a grate equal but reverse oscillatory motion. The shaft has fast thereon a sprocket gear 35 driven. by a sprocket chain from any suitable source of power. The shaft also has fast 'thereon a smaller sprocket gear 3'? which drives by means of a chain 38 to a shaft (not shown) corresponding to 32 and controlling operating mechanism, similar to that described, for controlling the grate segments of `the two upper grates. @n one of the segment trunmons of the lower grate l key a4 crank 39, which by a rod 4l() is connected to a crank 41 fast on the trunnion of the segment disposed at the bottom of the chute 22 so as to oscillate said segment with the other segments.

ln operation, assuming the apparatus is drying wet coal from a washer, the coal is fed through the chute 8 and comes to rest on the adjacent segment of the upper grate. The blower 3 is started and forces the hot gases under pressure into the casing. The grate operating mechanism is started up and as the adjacent grate sections oscillate in opposite direction, the coal is fed slowly forward across the upper grate, then falls through the chute 19 and is fed back and forthiacross the casing until inallyl delivered intermittently by the grate segment at the discharge end of the hopper 22. The stock is held in position in each of the transter hoppers so as to seal them and the gases .must therefore pass up through the slots 1 3 of the grate segments and through the bed of the coal resting thereon and in thus passing the coal is gradually and eectively dried before it is discharged into the hopper whence it passes by the chute 24 to the pulverizing mill, and having been brought to the requisite state of ineness is blown off through pipe 2G and delivered to the combustion chamber or other suitable point of use or storage. The movement of the grates prevents the checking or cloge ging of the wet stock and keeps it in motion and in a relatively thin sheet through which the hot gases under pressure can be forced. The advantage of blowing the hot gases in under pressure is that l thereby obtain a slight pressure within the casing which will prevent the ingress of air that would be dangerous where fuel is being dried as it might furnish the necessary oXygen for an explosion.

lll)

Obviously the shape of the drier and the character of the grates may he varied according to the duty required or the character of stock to he handled. By varying the speed of rotation of the crank disks, or the radii of the crank pins, either or both, the rate of feed can be varied and the number of grates can be increased or decreased according as the character of the product to be dried may require.

lfithout intending to limit myself to the details of construction shown, What claim, is

l. ln a Waste heat drier, a casing having rocking grate means to pass the products to be dried back and forth across the casing, and means to pass hot gases upwardly through the moving layers of stock.

2. A Waste heat drier comprising a. drier casing, grates arranged at different levels in the casing, means to feed the Wet stoclr to the upper grate, means to oscillate the grates to eifect a positive feed of the stock thereon transversely of the casing, and means to pass hot gases through the grates.

3. A Waste heat drier in accordance with claim 2, in Which a chute is provided to transfer the stock from each grate to the next lower grate, said grates being disposed to seal with the descending stock their respective feed chutes.

4. ln a Waste heat drier having a top stock inlet, a bottom stock inlet, means to force hot gases into the lower portion of the casing, grates disposed across the casing at different levels, each grate comprising segments having a foraminous stock support ing face terminating in an arcuate guard. means to oscillate adjacent segments in opposite directions to effect transverse feed of the stock across the grates.

5. A drier in accordance With claim 4, in Which the segments are provided With trunnions projecting Without the casing, the alternate trunnions on one side being connected for joint operation and the other alternate segment trunnions being connected for joint operation on the other side of the machine, and operating mechanism to oscillate said groups of trunnions in opposite directions.

In testimony whereof I affix my signature.

MARTIN J. LIDE.

l/Vitn'ess NoMm WELSH.

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