US2437899A - Suction-type grain dryer and cooler - Google Patents

Description

March 16, 1948. A. a. WELTY SUCTION-TYPE GRAIN DRYER AND COOLER Filed June 19,1944 3 Sheets-Sheet 1 fig Paulo March 16, 1948. A. B. WELTY SUCTION-TYPE GRAIN DRYER AND COOLER 3 Sheets-Sheet 2 Filed June 19, 1944 March 16,. 1948. A? wELTY 2,437,899

SUCTION-TYPE GRAIN DRYER AND COOLER Filed June 19, '1944 3 Sheets-Sheet 3 306%.: I diri fl we'Zfy Patented Mar. 16, 1948 SUCTION -TYPE GRAIN DRYER AND COOLER Albert 3. Welty, Moline, lll., asslgnor to International Harvester Company, a corporation of New Jersey Application June 19, 1944, Serial No. 540,967

4 Claims. 1

This invention relates to a new and improved suction-type grain dryer and is a modification of my grain dehydrator application having Serial No. 528,254, filed March 27, 1944 now Patent No. 2,410,851.

An important object of this invention is to provide for the drying of freshly picked grains by the particular means of drawing heated air up through a column of grain.

In my prior grain dehydrator device, I provided a means for blowing air over a furnace and thereupon upwardly through a column of grain to be dried. Numerous problems arose whereby it was necessary to employ special complex mechanisms in order that the dehydrating device should operate efliciently. It is an object of the present device to overcome the need for the special mechanisms employed in my previous device, to provide a grain dryer with a minimum of operating parts, and to still maintain the high standard of operating emciency.

Another important object of the present invention is to provide a means for drawing air over a furnace and up through a column of grain to be dried.

Another and still further important object is to provide a grain dryer including a column of grain and means for drawing heated air in at one level of the .column and means for drawing cool air in at another level of the column.

A still further important object is to provide a suction-type grain dryer wherein the supply of heat is completely utilized.

Other and further important obiects ol the present invention will become apparent from the disclosures in the following specification and accompanying drawings, in which:

Figure 1 is a longitudinal sectional view of the grain dryer of this invention;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1; and

Figure 3 is an end view of the device as shown in Figures 1 and 2.

As shown in the drawings:

The reference numeral I indicates generally a housing for a grain dryer which comprises several units, namely, a. fan housing II, a heatproducing chamber I2. a grain chamber I3, and a cooling chamber I4.

The principle of the present grain dryer is to draw air through the heat-producing chamber up through the grain chamber and thereupon discharge it to the atmosphere. Contrary to my previous device which forced air through a similar path of travel, the present device employs 58 drive through the pulley I8 and belt I9 and fur-- a suction fan within housing II for pulling or drawing heated air up through the column of grain to be dried and from there into the fan and discharged through an exhaust conduit I6, as best shown in Figures 1 and 2.

An engine I1 is mounted at one end of the grain dryer housing I0 and is adapted, b means of a pulley I8 and belt I9, to drive the pulley 20 which is keyed or otherwise fastened directly to the fan shaft 2 I. It is evident that the fan. not shown but positioned within the fan housing II, will be driven by the fan shaft 2| and create a suction on a side opening 22. This opening in the fan housing II communicates with the top of the grain chamber section I3 and is adapted to establish a suctionon the top of a column of grain within the section I3.

As best shown in Figures 1 and 2, the chamber I3 is surrounded with insulated walls 23 which prevent the escape of heat used in the graindrying process. A series of plenum chambers 24, 25, and 26 extend longitudinally of the chamber I3 and communicate at one end with the heat producing chamber I2, as shown at 21. The upper portions of the side walls of the plenum chambers are equipped with screened apertures 28. The suction fan is adapted to draw air through the heat-producing chamber through the passage 21 into the plenum chambers 24, 25, and '26 and thereupon up and out through the screened apertures 28.

The heat producing chamber is supplied with a furnace 29 which may be any one of several types, such as oil, gas, coal or the like. This furnace 29 is a sealed unit and exhaust gases are not allowed to escape into the heat producin chamber I2 but rather are confined within heat exchange conduits 30, which progress spirally upwardly around the furnace 29 and communicate with the furnace dome 3| through a conduit 32. The heat exchange conduits 30' extend upwardly and include a bank of heat exchange conduits 33 shown in dash lines in Figure 2. There is no communication between the suction opening 22 of the fan and the heat producing chamber I2 except indirectly through the grain'chamber I3.

The engine I1 is surrounded with a housing 84 which is fastened to the grain dryer housing I0. An opening 35 is formed in the grain dryer housing I0 and permits direct communication from the interior of the engine housing 34 to the heat producing chamber I2 of the grain dryer. It is apparent that the longitudinal positioning of the engine I1 is conducive to easy power take-oil 3 ther is conducive to the utilization of heat created by the engine l1 which complements the heat created by the iurnace 23 to eflect a drying of the grain. The forward end of the engine Il may be equipped with a radiator or the like, but in any event, there is some opening at the fore end of the engine housing 34 to permit air to be drawn in over the engine I! and back through the housing communicating opening 34 and thereupon to progress downwardly over the furnace dome 3i and around the heat exchange conduits 30 and 33, so that the air admitted to the plenum chambers 24, 23, and 23 through the passage 21 is quite hot. With the suction i'an drawing this hot air upwardly through a column of grain in the chamber i3, this column of grain will be dried to enable it to be stored without rear of spoilage. It will be understood, 01 course, that a sealed conduit 33 covers the opening]! in the suction fan housing I! and Joins with the grain chamber l3 through the opening 31. This prevents the fan from short-circuiting the travel or heated air and makes it impossible for heat to be drawn of! the furnace 23 up to the ian housing IS without first circulating up through the grain chamber I3. The arrows indicate the direction of air travel.

The grain to be dried is put into the hopper 38 whereupon it is raised from the bottom thereof by means of an elevator 33 which carries the grain upwardly to a point where it discharges into the grain dryer inlet hopper 40, as best shown in Figure 1. A centrally located, longitudinally extending worm 4| carries the grain fed to the hopper 40 along the entire length oi the grain chamber I3. As best shown in Figure 2, the worm 4| is positioned within a trough-like housing 42. This housing 42 is equipped with regularly spaced openings 43 on the under side thereof so that the grainmay be discharged downwardly into the chamber I3 along the entire length of the chamber. The grain is adapted to extend from a point at the bottom of the plenum chamber up to the bottom of the tubular housing 42. Discharge rolls 44 are positioned adjacent the sides of the plenum chambers 24, 2B, and 28, so that the column of grain moves continuously downwardly and the dried grain discharges at the bottom. The discharge rolls 44 are equipped with alternate intermittent slots 45 within which the grain deposits, and as the rolls rotate, the deposited grain is discharged into the cooling compartment i4 whereupon a worm 43 extending lengthwise of the compartment will carry the grain to a discharge elevator 41, as best shown in Figure 3, whereupon the dried and cooled grain is elevated and discharged through either of two spouts 48 and 43. The trough-like frame structure 50 adjacent the discharge rolls 44 is so designed that the grain descending within the'chamber i3 is concentrated on one portion or the rolls, in order that the grain pockets or slots 45 may be filled on the upper side and may be discharged into the compartment i4 as the rolls 44 rotate.

The compartment i4 .is termed a cooling chamber, for the reason that it assists in brlngingthe heated grain down to normal temperatures before it is removed from the dryer and stored. There is the possibility that storing of grain of very high temperatures will cause moisture to be condensed thereon. The bottom of the cooling compartment i4 is opened to the atmosphere through chamber l3, but rather they are designed to permit atmospheric air at room temperature to be drawn in through the passages 5i and 42 up around the loose-fitting discharge rolls 44 and up through the column of grain by reason of the suction created by the fan. of course, this will tend to reduce the temperature of the heated air as the cool room-temperature air combines with the heated air at the plenum chamber outlets 23, but this is not detrimental to the effective operation of the machine. The suction fan draws hot air into the chamber i3 at the level defined by the plenum chamber outlets 23 and draws cool air into the chamber I3 at the level defined by the discharge rolls 44 which is below the level of the hot air entrance. As the grain to be dried descends within the compartment [3, its temperature increases until it reaches the hot air openings 23 in the plenum chambers, and after passing that point, the cool room-temperature air acts on the grain to reduce its temperature so that, in fact, the cooling chamber begins immediately below the openings 23 in the plenum chambers. Cooling continues as the grain discharges downwardly through the rolls 44 and as it falls down the inclined V-shaped bottom 53 of the cooling compartment I4.

The exhaust furnace gases are more completely utilized by extending the bank of heat exchange conduits 33 around the fan to a vertical conduit 54, which communicates with the longitudinally extending conduit 35 buried within the column of grain within the compartment l3. This conduit 55 does not extend completely to the end of the housing I0 but rather falls short and permits the exhaust gases to pass outwardly into a superimposed housing 53 and thereupon is directed back through the outer housing 58 and thence discharged through the suction fan. It is possible that some of these exhaust gases will condense within this housing 53, and for that reason a drain 53' is provided at the end thereof and extends through the housing i0. It is necessary to supply the exhaust gases with some suction to maintain a continual flow of the gases, and in order to effect this suction, a valve gate 51 in the outer housing 86 and communicating with the suction fan, shownin Figures 1 and 2, may be adjusted at any degree of opening to obtain greater or less suction as necessary. The position of the gate 51 is such that the exhaust gases are above the column ofgrain and pass directly to the fan rather than proceeding down into the grain and thus contaminating it. The particular valve gate shown has an operating handle 53 extending out through the housing ID in order that the opening of the gate 51 may be adjusted. It is, of course, obvious that the valve may be any one of several types such as a sliding valve or some other suitable type.

Drive for the worms 4| and 46 and the discharge rolls 40 is taken from the tan driving shaft 2! by means of the pulley 58, belt 60, and a pulley Bimounted on a shaft 62. An idler pulley 83 is adapted to he angularly adjustably positioned so that the tension of the belt may be fixed as desired. The pulley 63 may be moved away from the belt to cause the belt to completely disengage from the pulley 59, thus acting as a clutch to stop motion of pulley Si and shaft 62. The shaft 62 extends rearwardly of the grain dryer. housing I 0 and has mounted thereon a small gear 64 which engages the gear 65 keyed or otherwise fastened to the shaft 63 of the worm 4|. The drive for the discharge rolls 44 and the worm 48 is taken from a rear extension 81 of the shaft 88. Mounted on this rear extension 81 is a pulley 88. The discharge rolls 44 have rearwardly extending shafts 89, the outer ends of which support sprockets 18.

It is a requirement oi this grain dryer that the discharge rolls 44 rotate very slowly, and to effect that result the particular drive as indicated in Figure 3 is employed. The pulley 88 is equipped with a crank pin 1| to which is attached a pitman 12. It will be evident that as the pulley 68 rotates, the pitman 12 will reciprocate vertically. The lower end of the pitman is attached at 18 to an arm 14 which is pivoted on a shaft 15. A ratchet wheel 18 is mounted on this shaft 15 and carries with it a sprocket 11 in a common plane with the sprockets 10. The arm 14 is equipped with a projection 18 to which is-pivoted a awl 19 for engagement with the ratchet wheel 18. As the pitman I2 is lifted upwardly, the pawl 19 engaging the ratchet teeth causes the ratchet wheel 18 to rotate in a clockwise direction as viewed in the device of Figure 3. The effective movement of the pawl 18 may be curtailed by the member 88. This member 88 is in the form of a circular segment and is pivoted on the shaft The vertex 8| of the segment 80 is adjustably positioned within the slotted bracket 82. The outer arcuate end of the segment 88 is adapted to coincide with the arcuate periphery of the ratchet wheel 18. The pawl 18, as shown in Figure 3, is thus prevented from contacting the ratchet teeth, and movement of the ratchet wheel 16 is thereby delayed until the pawl 19 passes beyond the upper limit of the segment 80. The segment 88 may be pivoted about its center 15 and fixed in any desired position within the slotted bracket 11 to eiiect any rate of ratchet rotation that is permissible between the limits of movement of the pitman 12. A second pawl 83 is resiliently held against the bottom of the ratchet wheel 18 by means of a spring 8t. This ratchet wheel prevents rearward or counterclockwise rotation of thetratchet wheel 18 when the pawl 19 no longer is engaged with the ratchet teeth. A chain 85 is wrapped around each of the sprockets as well as the drive sprocket 11, an idler sprocket 88, and the sprocket 81. The sprocket 81 is mounted on a stub-shaft 88 and acts as an idler sprocket in order to secure the 6 e drawing of hot air in at one level of the grain and a simultaneous drawing in of cooler air at a lower level of the grain contributes to an efllcient operating system. The entire system is greatly facilitated in its efllciency by a complete use of exhaust gases by means of a plurality of heat transfer conduits. It is foreseeable that combustion may eventually be so complete that exhaust gases may be mixed with warm air in proper direction of rotation of the sprockets 10 driving the discharge rolls M.

The upper end of the intake elevator is equipped with a pulley 89 mounted on a shaft 90 which extends within the elevator and drives the elevator flighting. A similar pulley 8| is mounted at the top of the discharge elevator 41 on a shaft 92. A further pulley 83 is mounted on a stub-shaft 9i and is in the same plane with the pulleys 88, 88, and M. A belt 85 encircles these pulleys in the manner shown wherein the small pulley 93 acts as an idler. It is evident from this arrangement of pulleys and belt 88 that drive is imparted from the pulley 88 to the elevators 38 and 41. The driving of the elevator 41 causes a driving of the worm 48 which carries the grain from the cooling chamber to the discharge elevator. A second pulley 88 is fastened to the shaft 92 and is adapted to drive a moisture testing device 91 operable by means of the pulley 88. An idler pulley 98 is mounted on a stub-shaft I08 afllxed to the housing 88.

The novel cooling method employed in this grain dryer is believed to be quite distinct from any cooling method heretofore employed. The

the direct drying of'the grain without fear of any contamination. This would, of course, result in a simpler and more economic machine. In furtherance of the system emciency, the incoming air is preheated by the engine I! as heretofore described. However, if the quantity of air taken in over the engine [1 is insufficient to satisfy the demand of the dryer, an opening may be employed in the side wall of the device at a point above the furnace which will augment the supply of air taken in through the engine.

What is claimed is:

1. A grain dehydrator having an insulated housing comprising an engine, a vertical grain chamber, an auger for feeding grain along the top of said grain chamber, graindlscharge rolls at the bottom of said grain chamber, said auger and discharge rolls rotatably driven by said engine, a heating plant requiring a supply of air, an air intake positioned over said engine, whereby air utilized by the heating plant is preheated, a communicating passage between the heating plant and the grain chamber, and suction means for drawing air in over the engine, through the heating plant and up through the grain chamber, said grain chamber having an auxiliary air entrance located beneath the discharge rolls and bypassing the heating plant and entering said grain chamber at a level beneath the level of the entrance of the hot air communicating passage and whereby the suction means draws cool air up from the auxiliary air entrance around the discharge rolls to mingle with the heated air in the lower portion of the grain chamber.

2. A grain dryer having a housing including a heating plant having an air inlet and a hot air outlet, said heating plant having its gases of combustion maintained separately from said air inlet and outlet, a grain chamber, a communicating passage between said hot air outlet and said grain chamber, heat exchange conduits carrying the gases of combustion around the air inlet and through a longitudinally extending sealed compartment within said grain chamber, said sealed compartment having a port providing communication between the compartment and the top of the grain chamber, valve means in the port for regulating passage of exhaust combustion gases, and a suction fan at the top of said grain chamber drawing air into and through the heating I plant, through the grain chamber and out a discharge through the suction fan and drawing out exhaust combustion gases in an amount dependent upon the position of the valve means.

3. In a grain dryer having a housing including a vertical grain chamber, means for heating and cooling grain in said chamber, said grain chamber having an opening intermediate the top and bottom for the entrance of hot air, and said grain chamber having an opening in the bottom thereof for the entrance of cool air, suction means on the top of the grain chamber for drawing both hot and cool air upwardly through the grain,

whereby the cool air at the bottom of the grain chamber above the opening for the hot air, means for moving grain downwardly through said grain chamber, a grain discharge at the bottom of the grain chamber whereby grain originally heated at the top is cooled before being discharged, said discharge including a plurality of rolls having spaced pockets adapted to receive a quantity of grain and upon rotation 01' the rolls to empty the grain beneath the. grain chamber, a housing structure adjacent the rolls providing sufllcient space for passage of air, and a V-shaped bottom for said grain chamber, said cool entrance opening located in the sides of the V-shaped bottom in a manner to permit grain emptied from the pockets of all the rolls to flow down over the opening to the apex of the V-sh'aped receptacle.

4. In a grain dryer having a housing including a vertical grain chamber, means for heatin and cooling grain in saidv chamber, said grain chamber having an opening intermediate the top and bottom for the entrance of hot air, and said grain chamber having an opening in the bottom thereof for the entrance of cool air, suction means on the top of the grain chamber for drawing both hot and cool air upwardly through said grain chamber, whereby the cool air at the bottom of the grain chamber cools the grain therein and the hot air tempered by the cool air heats the grain in the chamber above theopening for the hot air, a grain discharge at the bottom of the grain chamber whereby grain originally heated at the top is cooled before being discharged, said discharge including a plurality of rolls having 8 spaced pockets adapted to receive a quantity of grain and upon rotation of the rolls to empty the grain beneath the grain chamber, a housing structure adjacent the rolls providing sufllcient space for passage of. air, a V-shaped receptacle beneath said grain chamber whereby the grain emptied from the pockets of all the rolls will flow down to the apex of the V-shaped receptacle, and a longitudinally extending worm within the apex of the receptacle for moving the grain to one end thereof.

ALBERT B. WELTY.

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

UNITED STATES PATENTS France Oct. 10, 1922

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