US1384047A - Process of drying granular material - Google Patents

Description

C. VV. CAHIER.

IJROCESS 0F DRYING GHANULAR MATERIAL. APPLICATION FILED APR.22, 1918.` RENEWED DEC. in

July I2, IIQZII.

54 @e (f4 62 5,52%56 i@ 4@ C. VV. CARTER.

PROCESS OE DHYING GRANULAR MATERIAL.

APPLICATION FILED APR. 22. 1918.

55 the time required CLRENCE W. CMTER, 0F MJTNIEAPLIS, TEIN'NESOTA.

PROCESS OF DRYEENG GRANULAR IWATERIAL.

i Application led April 22, 1918, Serial No. 229,910. )Renewed Decem To aZZ whom t may concern: Y

Be it known that l, CLARENCE W. CARTER,

a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Processes of Drying Granular Material, of which the following is a specification.

My invention relates to a process of drying granular material and in particular 'to a process of drying grain in which heated air is passed through a mass of grain having the form of a vertical column contained in large bins from the bottom of which the l5 grain is drawn off after it has been dried.

ln processes of this kind in use before my invention the grain has been drawn of slowly at the bottom of the bin and the temperature to which it is feasible to heat the air is limited, since if the temperature goesmuch beyond a certain degree the grain is seriously damaged by the heat. lt is wellknown that if material which is being heated is thoroughly stirred at su'iciently short intervals of time, it can be 'subjected to a much greater degree of heat without injury than is the case where it is not stirred or is only slightly stirred. Before the time ofmy invention no satisfactory way of thoroughly stirring and agitating the grain had been devised, it not being practicable to introduce mechanical stirrers or agitators into the bins, and since the slow passage of grain out of the bottom causes but slight miXin of the mass, the temperature of the heate air has necessaril been restricted, as ypreviously stated. urthermore, it has previously been the custom to draw the grain through restricted openings at the bottom of the bins,

and this produces currents in the mass, some portions thereof moving downwardly much faster than other portions. Therefore by the present manner of drying in bins, not only is an undue amountV of time consumed but lthe grain is not uniformly dried. kThe object ofv my invention is therefore to overcome the above-mentioned defects in regard to drying, and ll accomplish this object by making a radical change in the process. ln short, ll

570 have devised a practical way of thoroughly stirring and agitating the mass at short intervals of time. ll am therefore able to emplo,z much higher temperatures than previous y employed and thereby greatly shorten to thorougy dry the grain, and to also dry it much more umi- Speciication of Letters Fatent. Pattmltcedl July 12, 921.,

ber 27, 1920. -SEIal N0. 433,432.

formly than has been the case heretofore. ll do this by causing the mass of grain to descend at intervals by a progressive showering action. which produces a complete re-distribution of the kernels of grain such as is obtained by a stirring or agitating operation. In order to initiate this redistributingeifect, l suddenly remove considerable portions of the mass from the bottom thereof and do this at intervals such that the time between successive removals of material is considerably longer than the time required for the removing operation. When the bottom portion of the mass is suddenly removed, a corresponding empty'space is left atL the bottom vof the bin and the mass is therefore substantially unsupported except for such support as it may have by being in contact with the numerous air ducts which extend through the mass. 0n account of the frictional resistance odered by these air ducts, the mass when left unsupported at the bottom does not fall as a unit, butthe bottom portion thereof falls first, then a portion above the same falls, and so on until the top of the mass is reached, thus producing a showering action starting at the bottom of the unsupported' mass and'running progressively up to the top thereof. .This showering or redlstributing eect is also aided by the fact that the grain is progressively moister from bottom to top and the dried grain at the bottom does not tend to cohere as much as does the grain farther up in the bin. l v

The full objects and advantages of my 1n` vention will appear in connectlon withthe detailed description thereof and are particu-l larly pointed out in the claims. Y

Referring to the drawings, whlch illustrate a suitable apparatus for carrymg outV my improved process,-

bin provided with means for carrying out my process. Fig. 2 is aI side elevation thereof. Fig. 3 is a topl plan view of the operatlng mechanism. Figs. 4f, 5 and 6 are vlews 1n vertical section illustrating di'erent positions assumed b the. grain which is being dried and disc arged by the discharge pockets. j

lln the drawings 10 designates one of the customary drying bins which are provided with upper conduits l2 for het air land lower conduits 1li for cold air. rThe customary air' ducts extending across the bins are designated by the character V1 6, The hopper into gaa land 22 are secured to i covers which the dried grain is discharged is designated by the character l8. Two beams 2() opposite ends of the hopper 1.8 and these beams are provided with journal 'bearings for a shaft 24. Se-

' .curedl to this shaft are three radial plates or \'to which are secured a number of stepped outer end of'said arm is a pawl 54 which isv driving pulleys 32 for changing the speed of operation of the device. Secured to the shaft 30 is apinion 34 in mesh with a gear 36 which is secured to a stub shaft 38 to which shaft is also secured a pinion 40 in mesh with a gear 42 loosely mounted on the shaft 24. It is evident that-a reduction gearing is thus provided between shaftf30 and the gear 42. On one of the spokes of this gearis a projecting lug 44 for a purpose which will presently appear. On the end of the shaft 30 is a'crank arm 46 having a wrist pin 48 for operating a connecting rod 5() which is pivotally connected with an arm 52 loosely mounted on the shaft 24. On the adapted at certain times to engage one of a l' series of three notches 56 provided` in the periphery of a disk 58 secured to the shaft 24. At other times this pawl slides idly back and 'forth .upon the periphery of the disk. A bracket 60 carries a stop pawl 62 which is adapted to successively engage the notches 56 to prevent backward movement of the shaft 24. Secured to the shaft 24 is an arm 64 disposed in the path of the lug 44 previously referred to and adapted to be engaged at v imes by .said lug in the forward movement of the wheel 42. 4It is evident lfrom this description 'that the' pockets have a comparativel long period of dwell under the bottom of tlie bin, and they start to move with a slow turning movement which is soon converted into a quick ,turning movement to discharge the grain. This quick turning movement occurs as soon as the disk 58 has been turned sufficiently far to bring one of its notches within reach of the pawl: 54. The partial cover members 28 prevent escape lof the grain from the right-hand end, as will be evident from Figs. 4, 5 and 6.

The operation of the mechanism will be'A readily understood from the foregoing description. Upon applying the power toturn the shaft 30, the gear 42 will be rotated upon the shaft 24 at a greatly reduced speed. The

rotation of the gear 42 of course imparts rotation the shaft 24 only when the lug 44 'comes in to engagement with the arm 64. When this occurs,- it is evident that the Shaft .juriously 24 and the discharge pockets will at first be turned slowly. The connecting rod 50 is oscillated by the crank arm 46 and causes the pawl 54 to oscillate idly back and forth upon the periphery of the disk 58, except that when it is engaged with one of the notches. 56 it imparts a rapid turning movement to the disk 58 and tothe shaft 24, -carrying the discharge pockets. It is evident from an inspection of Fig. 1 that .the pawl d'oes not oscillate sufficiently far to engage-.a notch in the position shown, and that itis necessary for the lug 44 to catch up with the arm 58 and impart a turning movement to the disk 58 until thepockets arrive at about the unsupported at the bottom. The pockets then remain at rest until the lug again catches up with the arm. It will thus be seen that a pocket remains in the filling position shown in Fig. 4 .for an appreciable length of time and then moves slowly to about the position shown in Fig. 6. The pocket is then moved very quickly to dischargingv position and the next pocket brought into the lling position under the bin.' When the mass of grain is left unsupported at the bottom, the space from which grain has just been removed is not instantaneously filled, since vthe mass is partially supported by the baflie plates previously referred to. A showering action results which is aided vby the facts that the pressure at the bottom of this mass is greatest and the grain is drier and has less c0- herence than the grain higher up in the bin. The result is that the bottom portion of the mass falls first in the forml of a shower, and a showering'action extends progressively up to the top of the mass of grain. This manner of descent causes tion vand mixing of the kernels of grain and prevents them from being acted upon inby the high degree of heat which is employed. The timing of rotation of the pockets is such that each pocket remains at material left unsupported beneath the baffle a thorough redistribu- Fig. 4-4 shows a pocket filled by the falling of the plates, while Fig. 5 shows the showering action occurring farther upin the mass.

l claim:

l. A process of drying granular material which consists in supporting a vertical column of said material at its bottom, passing heated air through said column, and periodically withdrawing said Support to an extent suficient to cause the entire column of material to move downward uniformly throughout its cross section.

2. A process of drying granular material which consists in supporting a vertical column of said material at its bottom, said column being of a predetermined length,

passing heated air through saio column throughout the principal part of the length thereof, periodically withdrawing said sup port to an extent sufficient to cause the entire column of material to move downward uniformly throughout its cross section, and ,regulating the intervals of time between each of said withdrawals so that the part of the material which moves past the point of support and is discharged from the column will have been suitably dried.

ln testimony whereof l hereunto affix my signature.

CLARENCE w. CARTER.

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