CA2218901C - Harvesting system and method - Google Patents

Abstract

A harvesting method which removes chaff and weed seeds from the field with the harvested grain, and separates the chaff, grain leavings and weedseeds from the grain in a stationary yard plant. The chaff, grain leavings and weed seeds are compacted and crushed in a mill for use as animal feed. Simplified harvesters have augmented holding tanks, one version of which can be attached to(and detached from) existing farm tractors. A specific integrated yard plant separates and cleans harvested grain and compacts and crushes chaff, grain leavings and weed seeds.

Description

H"~VF~TING SYSTFM ANn MFTHon This application is a division of application 2,180,691, filed 8 July, 1996.
FIELD OF THE INVENTION
The present invention relates to harvesting systems and more particularly to the cleaning of harvested crops.
BACKGROUND
At present grain harvesting is carried out using combine harvesters, which thresh the grain in a thresher, then separate the grain from chaff, straw and weed seeds. The combine harvester keeps the grain and rejects other material. Its 10 L hl esl ,er breaks the grain from the stalk or pod. A degree of separation is achieved in rotary threshers by using apertures in the thresher tube which allow p~ss~ge of grain. The separation is not clean, the straw portion includes grain and chaff, and the grain portion includes chaff and straw. When the thresher is a cylinder and a concave, the concave has apertures to pass the grain portion, but the straw portion 15 is passed along a straw walker to further remove grain from the straw. The grain portion includes chaff, grain and weed seeds, which are then passed through a sieve with air blowing upwards. This is called the shoe and includes the aspiration (blowing) and sieve (cleaning) apparatus. The grain falls downward, while chaff and weed seeds and any straw are blown upward. The chaff, straw and weed seeds are 20 left as waste by-products in the field, while the grain is transported to the combine's bin for subsequent field removal. Thus the economic value of chaff and weed seeds is lost. Moreover the currently used method spreads weed seeds through the fields, necessitating intensive, extensive and expensive pesticide and herbicide applications.
This invention concerns a harvesting system and method designed to simplify and improve existing grain uop harvesting techniques. The method separates straw (or its equivalent) in the field from chaff, grain, and weed seeds, rerer,ed to herein as Ugraffn. The materials other than straw are transported to an automatic cleaning plant. Here the grain is cleaned by a stationary cleaning machine, and the separated materials, the "savingsD, are milled for use as animal 5 feed. The milled savings will include densified grain leavings (small kernels, fines, leaves, hulls, stalks1 stems, husks and the like) when present along with chaff and weed seeds. The system includes a simplified harvester, and a separate processing plant. It is the processing plant that is the subject of this divisional application.
Other anticip~ted advanlages of the new system compared to the present co"lL..ling method are in a cleaner grain product, providing farmers with higher prices and less freight demurrage. Harvesting equip,l,eilt will be less costly.
Equipment depreciation is less bec~use the automatic cleaning plant is stationary and incurs less wear. The field unit is simpler becAI~se it has none of the cleaning 15 and separdling equipment of the combine.
Although the term 'grain' is primarily regarded as cereal grain refer, ing to the seeds of grasses, such as, but not limited to, barley, corn (maize), millet, oats, rice, rye, wheat and many lesser known domesticated grasses, it is not limited ll,ereto in instant application, since the new technology may be used as well for 20 oilseeds, legumes and other domesticated plants. The term 'grain' is intended to cover besides the usual definition, all Canadian prairie crops including small grains, canola, sunflowers, corn, lentils, peas and the like.
SUMMARY
Accor~;ng to one aspect of the present invention there is provided a 25 method of processing a harvested crop co",prising graff containing grain, chaff and other residue, said method comprising:

separating the graff into grain and savings containing chaff and other ,nalerial separated from the grain; and milling the savings.
TheUgraff'' is a combination of grain, chaff, residual straw, weed seed 5 and any other material that remains with the grain after initial threshing. In a conventional harvesting method, using a combine harvester, this mixture is not collected. The grain is cleaned in the field by the combine to remove chaff and other material. The cleaned grain is l~anspGiled from the field, while all othermaterials are deposited on the field.
Mixing the chaff and grain leavings and other residue with the threshed grain yields a mixture that may be handled more readily than material without the grain or with unthreshed grain. Threshed grain kernels flow relatively freely and can thus be moved by auger. Neither chaff nor grain leavings flow well alone. Chaff tends to bridge. Unthreshed grain, heads or ears, and straw also do15 not flow well. For ease of handling, the prese"t method threshes the grain and mixes it with the chaff, grain leavings and resid~ straw to produce a graff mixture that is more easily handled.
Cleaning the graff cor"pone"t with a stationary yard unit at the cleaning site yields a cleaner grain that alllacls a higher price. The densified20 residue, rere"ed to as "savings" from the cleaning process also has an economic value. The savings are produced by compacting the crop residue in a milling step to produce an animal feed with a high nutrient value. Grain can be added at the milling stage to enrich the resulting mixture.
When grain leavings are present, and the graff is separated into grain 25 and savings, the latter includes the grain leavings The chaff, grain leavings and weed seeds p~"ic~" are treated to coi"pa~ and crush the chaff, grain leavings and weed seeds, preferably by milling.
In the preferred ",ethod of cleaning the graff is aspirated to remove liftings, screened to remove matter larger than the grain, screened to remove matter smailer than the grain, and blown through with air to remove matter lighter than the 5 grain. The liftings and matter larger, smaller and lighter than the grain may then be combined and milled.
According to another aspect of the present invention there is provided a cleaning unit for cleaning graff including grain and chaff, said cleaning unitcomprising:
receiver means for receiving the graff;
grain cleaning means for separaling the graff into grain and savings containing chaff and other material separdled from the grain; and a mill for milling the savings.
The prerer,ed cleaning unit includes aspirator means for aspirating the graff to remove light weight and fine liftings; coarse screening means for sueening the graff, to remove matter larger than the grain, fine screening means for screening the graff to remove matter smaller than the grain, and blower means for blowing air through the graff with air to remove matter lighter than the grain. The liftings and matter larger, smPll~r and lighter than the grain are then be mixed and milled.
The mill may be a roller mill or a hammer mill. Preferably the grain outlet from the cleaner is coupled to a conveyor, for example an auger leading to one or more grain storage bins. The grain outlet can be connected by an auger to a grain dryer, which is in tum connected to an auger leading to the grain bins.
The cleaning system may include a cyclone separator having an inlet coll"ecle~ to the l~ftings outlet of the aspirator means. The cyclone has a material outlet and an air outlet, with the air outlet connected to a cyclone fan. The material outlet is connected to airlock valve.
Conveyors connect the fine material outlet, the residual material outlet of the multi-screen grain cleaner, and the cyclone airlock valve to the mill.
The compacted and crushed chaff and weed seeds (savings) are a 5 high nutrition animal feed. Nutrients from the crushed weed seeds enhance the nutritional value of the chaff. r,ererably the feed also includes cG"",aoted andcrushed grain leavings to further enhance the nutritional value of the chaff. Ifdesired, grain may be added at the compacting and crushing stage to further enrich the resulting feed.
The practice of the invention resluces grain loss during harvesting by collecting s~ sl~nlially all of the grain in the graff. This has the subsidiary effect of ",ini",i~i"g volunteer grain growth. Bec~use the weed seeds are collected as well, weed growth is significantly reduced, li",iling the need for herbicides. The stationary cleaner unit can provide a cleaner grain product than a conventional mobile combine. With the presenl invention, s~hst~rltialJy all of the chaff, grain and weed seeds are removed from the field, leaving only straw. The residual compacted and crushed chaff and weed seeds are useful as animal feed, especially for stockraising on grain farms. The nutritional value of the feed is augmented by removing ~."der~i ed grain kernels, fines and other grain leavings from the harvested field, and adding these to the chaff and weed seeds.
The harvester field unit of the invention may be lighter, faster, more energy efricient, simpler and less expensive than a combine harvester. It may bemade with y,eal~r ca~.acily than a combine. The invention may increase the use and hence productivity of farm grain trucks.
The slatio"aly, cleaning plant, may be more efficient in cleaning and more energy efficient than the mobile fuel powered combine cleaning plant.

BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which illustrate exemplary embodiments of the present invention:
Fig. 1 shows a flow chart to illustrate an embodiment of the system of the invention;
Fig. 2 shows a part sectional view of a yard plant cleaning and separaling unit combined with a seed crushing and chaff densifying unit in this case the unit is mobile;
Fig. 3 shows an exploded view of an embodiment of a self-propelled lhresl)er of the invention;
Fig. 4 shows an exploded view of an embodiment of a self-propelled thresher of the invention;
Fig. 5 shows an exploded view of another embodiment of a wrap-around thresher of the invention;
Fig. 6 shows an exploded view of anotl,er embodiment of a wrap-around ll ,resher of the invention;
Fig. 7 shows a top view of the embodiment of Fig. 2 using a different power system;
Fig. 8 shows a control panel for the e",bodi",enl of Fig. 7;
Fig. 9 shows a side part sectional view of another embodiment of a wrap-around thresher of the invention;
Fig. 10 shows a top part sectional view of the embodiment of Fig. 9;
and Fig. 11 shows a side part sectional view of another embodiment of a wrap-around combine of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is now illuall ated by rererence to the preferred e"lbodi",el)ts ll,ereo~. The numeral 10 generally indicAles a system of the invention (Fig. 1), header 12, which may pick up a swath, direct-cut or strip-cut the standing grain crop. The header cuts the crop leaving behind stubble at a height chosen by the farmer. Harvester 14 is directly attached to header 121 and includes a thresher to thresh the grain. The grain, chaff and weed seeds proceed together into a holding tank il It6y~dl with the harvester, desirably with a bottom agitator to help flow from the plant. The holding tank is preferably at least about twice the size of those currently in use on combines. The separated straw is deposited in the field at the 10 far",el's pleasure either directly for later baling, or optionally through straw chopper, si,redder and spleader 16 to decol"pose in the field.
Built into harvester 14 is high volume and time saving auger 18, which is used to load field truck 20. As truck 20 preferably has truck box sides raised by about 3 feet above normal to increase load capacil~, the auger arm is raised to 15 clear these. Wheat chaff, weed seeds and wheat grain have about twice times the volume of wheat grain alone, and about 1.16 times the weight of wheat grain alone.
Volume and weight ratios vary with uop harvested and moisture content.
Figs. 3 to 6, and 9 to 11, indicate specific threshers: self-propelled thresher 130, (Fig. 3), self-propelled thresher 154 (Fig. 4), wrap-around thresher 20 146 (Fig. 5), wrap-around thresher 166 (Fig. 6), wrap-around thresher 200 (Figs. 9 and 10) and wrap-around thresher 216 (Fig. 11) which have conventional interchangeable l~ader 132, which as those skilled in the art realize can be a direct cut, swath pick-up, or stripper header. Elevator 134 carries the cut crop to rotary ll ,resher 136, or thresher cylinder 156 and coopera~ing concave 158, which 25 separates the straw from the rest of the crop. In the self-propelled versions of the ~I,resl,er, 130 and 154, elevator 132 is 64h inches wide as are rotary thresher 136, or thresher cylinder 156 and concave 158. In the wrap-around versions elevator 132 is 55 inches wide as are rotary thresher 136 or ll,resl,er cylinder 156 and concave 158. Either rotary tl,resl,er 136 or concave 158 may include apertures to allow grain and other material except straw to pass directly into holding tank 138. Material other than straw may be carried by conveyor augers 137 to holding tank 138 optionally equipped with agilalo,~ 140. Straw and other material mixed therewithmay be p~ssed by overshot beater 159 into tine separator 160 which has paired side by side tine separdlors conlaining tine rotors 161 having tine arrays 162 thereon. Material is urged along the tine separalors smaller material than straw10 passing through gratings 164 into holding tank 138. The wrap-around versions 146 166 200 216 are mounted on conventional tractor 148 and operated by the usual tractor PTO (power take-off) which requires about 200 hp. In Figs. 9 and 10 the tractor PTO operales shaft 206 which powers elevator 134 thresher cylinder 156 overshot beater 159 and tine rotors 161 by gear belt drive (also known as HDT
15 timing belt or poly-chain) through belt and sheave arrangements 208 210 212 and 214. In version 200 (Figs. 9 and 10) a support wheel 202 with support struts204 and 205 is provided for elevator 134. In all versions straw spreader 142 spreads straw on the field. These threshers all feature a large holding tank and lack grain cleaning e~u~pment except 216.
In Fig. 11 is shown wrap-arolJnd combine 21 6 which embodies conventional combine grain cleaning equipment 218 including screen 220 distribution auger 222 sieves 224 aspirator fan 226 which blows chaff weed seeds and grain leavings out and tray 228 with acco",pa"ying auger. Auger 144 isalso shown in all~l.,dli~/e non-use position 145.
Thus far the process has harvested all the grain. Using existing combine r"ethods s~ sl~nlial amounts of grain are put back on the field with the _ 9 _ chaff, 6.4% for wheat, 5.2% for barley and 3.7% for canola, as per~"tages of total chaff weight. Combine grain average losses (as distinct from header grain losses) are esli",ated at between 3.375% to 3.75% for wheat, 3% for barley and 2.875% for canola, as percenlages of total grain harvest. These losses are due to the thresher, the straw walker and the shoe (blowing aspirator and cleaning sieve). Harvester 14 of the invention doesn't have a shoe, thus saving grain loss from the shoe.
The weed seeds harvested will amount to about 50% of all weed seeds available at harvest time.
Besides the value of capturing more grain, less grain loss means less 10 volunteer growth. In addition the removal of weed seeds with the grain will substantially reduce weed growth.
The chaff and grain leavings have to be combined with the threshed grain for ease of handling. Threshed grain kernels flow like a liquid or fluid. Chaff alone doesn't flow well and tends to bridge. Grain leavings also don't flow well15 alone. Grain kernels are flowable or pourable, which can thus be moved by auger.
Since chaff and grain leavings tend to bridge when passing through narrow openings, they must be mixed with flowable or pourable material for ease of handling. For practical movement of the chaff and grain leavings, they are when mixed with ll"es~,ed grain to produce the graff, which is flowable or pourable.
20 U"thresl,ed grain, heads or ears, does not flow well. For grain and by-products to be easily handleable, the grain must be threshed and the by-products must be mixed in with the grain. Straw also does not flow alone. In practice the grain is best ll,reshed in the field, and the flowable mixture of chaff, grain, grain leavings and weed seeds l, ~nsp~l led elsewhere for cleaning and separating.
Another high volume, time saving, auger 22 unloads the grain truck into surge receiving bin 24, which is part of automatic yard plant 46. Surge bin 24 has a large holding capacil~ and prererably a bottom agitator to ensure steady flow into yard plant 46. Auger 26 carries the chaff, grain and weed seeds to stationary separating and cleaning machine 28. Combine harvested grain must be cleaned again for market purposes. Machine 28 has more cleaning stages than combines, 5 and produces a significantly cleaner product than combine harvested grain, which is typically docked by 2 to 4% for uncleaned grain. Yard cleaned grain will be 'export' quality, with less than 1% dockage. The stationary yard cleaning machine 28 has the advantages that it is easier, simpler and cheaper to clean and maintain than the combi"e cleaning machine which is intricate, in a small space, awkward and 10 expensive to repair and maintain. Because it is stationary yard cleaning machine 28 takes less abuse than the co",L.ne cleaning machine, and thus lasts longer and depreciates less. Since the yard cleaning machine is built on a solid foundation it can be advanlageo~sly positioned for each individual farm. The cleaned grain is then carried by auger 36 to optional grain dryer 38, which can be incorporated into 15 the yard plant 46, more easily, simply and with less labour than the present system.
Grain dryer 38, when available makes drying easier and so enhances grain quality, it can also extend the harvest time. The grain whether passed through grain dryer 38 or not, is then p~ssed to bin 40, whence it may be carried by optional auger 42, usually a stationary overhead auger, to optional storage bins 44. The grain can be 20 adva"tageously directed to selected bins separalely to even out moisture or quality.
The residue of chaff and weed seeds from cleaning machine 28 is carried in yard plant 46, to crushing and densifying machine 30 prererably a roller mill, which densifies (co"~pa(,ts) and crushes the chaff, prer~rably to double its original density, while con,pacti"g and crushing the weed seeds. The chaff may then be moved by 25 auger 32 to chaff bunker 34, which is desirably covered by a tarp, to prevent blowing, alternatively the chaff can be moved by front end loaders.

A specific yard plant embG.lying cleaning/separating 28 and seed crushing/chaff densifying 30 ele",e"ls is shown in Fig. 2. Plant 48 is mounted on trailer 50 and is about 17 feet high by 24 feet long and 8 feet wide. Although this particular version is mobile, so that it can be tested at a convenient construction 5 site, before moving it elsewhere, generally the plant is intended to be stationary.
Yard plant 28 in any event is intended to be used when stationary, and no provision is made for use while moving. Grain is fed into grain feed inlet 54 by auger 26 (not shown in Fig. 2). Inlet 54 has upper 56 and lower 58 level indicators (sensors),when upper indicator 56 indicates inlet 54 is full, grain flow is stopped, when lower 10 indicator 58 indicates inlet 54 is empty grain flow is resumed. Below feed inlet 54 is aspirator 60, which has top feed roll 62 allowing grain to free fall down aspiration column 64 to base 66. Feed roll 62 is regul~ted to control speed of material intake into aspirator 60. Air passes in through air inlet 68 through a set of baffles 70 which force air through the falling grain and then through another set of baffles 72 15 aspirating light chaff, grain hulls, residual straw, grain fines into duct 74 and cyclone 76. The clean grain falls into base 66, where weighted door 78 allows grain to fall into grain cle:l~er 80. Aspirator 60 as shown is an open circuit vertical drop aspirator with a six pass aspiration column having a 56 x 12 inch opening and a 7 foot vertical drop. Operating about 5,600 cfm it can handle about 700 bushels or 19 20 metric tons per hour of whole grain, chaff and seeds. Feed roll 62 is driven by a 1 hp electric motor. Cleaner 80 has top hopper 82, which gravity feeds grain onto upper scalping screen 84, which p~sses grain and retains large material, the grain then falls onto lower scalping screen 86 which again p~sses grain but retains material larger than grain but smaller than the holes in screen 84. The grain then 25 falls onto fine screen 88, which doesn't pass grain but does pass finer material. The grain during falling is deflected by deflector plate 90 while fan 92 passes an air current through it blowing lighter material clear of the grain. This material emerges togell,er with that removed by the scalper scree"s to fall into hopper 94. The fines fall into hopper 96, while the clean grain discharges to hopper 98 attached to auger 100. The other two discharges to hoppers 94 and 96 are removed by auger 102.
5 Cleaner 80, which has a capacity of up to 300 bushels or 8 metric tons per hour, has a 3 hp electric motor, which drives fans 92 and vibrates screens 84, 86 and 88.
The aspiraled "~aterial from aspirator 60 pAsses into cyclone 76 where it is forced around inner tube 104 spiralling downward, the centrifugal effect urges the chaff into the walls and down into cone 106. Cyclone 76 is 40 inch external diameter and 10 stands about 1 1 feet tall. At the base of cone 106 the chaff p~sses into airlock valve 108, which discharges into hopper 112 of auger 114. Airlock valve 108, driven by3/4 hp electric motor 110, has 10 inch square inlets and outlets and an eight vaned rotor. Centrifugal fan 114, driven by 7 hp electric motor 116, has a capacity of85,000 cfm, and through ducts 74 and 118 provides air for aspiralor 60 and cyclone 15 76, it ~iscl,~ges through outlet 120. Augers 102 and 115 discharge the savings from the grain into hopper 122, which feeds into roller mill or hammer mill 124,either can be used. When mill 124, is a roller mill it is driven by 15 hp electric motor 126. A s~oeciric roller mill designed to crush weed seeds and densify chaff has diagonally grooved rolls. The rolls are 10 3/4 inch diameter, with diagonal grooves, 20 about 3/32 inch deep and about 3/32 inch wide, spaced about 5 or 6 per inch of width of the rolls. The rolls are geared to rotate at different speeds, one about 10 to 15% faster or slower than the other, typically one at about 350 RPM the other atabout 400 RPM, as those skilled in the art are aware rotational speeds and ratios can be varied. The clearance between the rolls is between 3 and 10 mils (0.003 and 25 0.010 inch), that is they don't quite touch (a normal sheet of paper is about 4 mils), which has two main effects - crushing weed seeds and grain leavings and tearing chaff into smaller r,ay",enls. Mill 124 discharges into hopper 128 of auger 130.When seed crusher and chaff densifier 30 is a hammer mill, a more powerful electric motor 126 is required up to a 15-50 hp motor.
In Fig. 7 is shown another power system for yard plant 48, in which electric motor 168, preferably a written pole motor, provides power. Most farms have single phase electric power, and triple phase power is not available, which limits the amount of electric power which can be used. The written pole electric motor has several advantages, it is a precise power single phase ride-through device, having two or four poles, it is fairly lightweight 1200 Ibs., it can provide between 25 and 30 10 rated hp using single phase electric power, along a shaft running up to 1800 RPM, and is prefera~ly used to power the plant, except motor 170 driving aspirator feed roller 62. Since feed roller 62 requires a variable drive, it cannot be run at a steady speed, and needs a separate variable speed motor. 2 inch steel line shaft 172 iscollne~;ted to written pole motor 168, by a gear belt drive, (also known as HDT,15 timing belt, or poly~hain) at a 1 :1 ratio. Bearings 198 support line shaft 172 about a foot above the deck or floor. Cleaning machine 80, airlock valve 108, aspirator fan 114, and roller mill 124 and augers 102 and 115 are connected to line shaft 172 by gear belt drives (also known as HDT, timing belt, or poly-chain) 186, 188, 190, 192, 194, and 196 which drive the devices. Each drive consists of two sheaves and a 20 belt, set appropriately to increase or reduce RPM for a particular drive. As those skilled in the art are aware, where the rerluction of RPM required is sufficient, a gear reduction box may be employed. As those skilled in the art are also aware adiesel motor or a tractor PTO may be used to drive line shaft 172 instead of electric motor 168, control panel 174 (described in Fig. 8) is ~ cent motor 168.
In Fig. 8 is shown control panel 174, for the written pole motor yard plant. This has manual-auto-off switch 176, push button switches having indicator lights 178, ind;calor lights 180, current meter 182 and aspirator feed control 184.
The control panel works as follows in when switch 176 is in auto mode the written pole motor 168 starts and drives rolling mill 124, air lock valve 108, fan 114, and cleaning machine 80. Twenty seconds later the l,an:jrer augers 102 and 115 kick in 5 as does aspirator feed roller 62. Three seconds after this the feed system activates into bin 54. This bin has automatic high and low switches which control its feedauger. Three seconds after the feed system activates the monitoring system switches on, and monitors the rolling mill 124, air lock valve 108, fan 114, andcleaning machine 80 to sense loose drive belts and similar problems. There is a full 10 hopper sensor on rolling mill hopper 122, when this is triggered, transfer augers 102,115 and asp.rator feed roller 62 shut down. Written pole motor 168 shuts down twenty seconds later to allow the rolling mill 124 to clean out, since the written pole motor cannot start it loaded.
The entire yard plant 46 as well as yard cleaning machine 28 and 15 seed crushing and chaff densifying machine 30 are suitably entirely automated, and can use electrical power, which is more energy efficient than mobile combine cleaning machines which are fossil fuel powered. The yard plant is intended to utilize as much existing farm equipment as possible to aid in conversion of former harvesting systems to the harvesting system desuibed herein. Yard plant 46 20 besides producing more and cleaner grain, also produces densified chaff and uushed weed seeds both of which contain fat and protein. Untreated chaff has a nul,ilional value between that of straw (low) and hay (high). One esli,nate gives it 75% of the nul,ilional value of tame hay (equivalent to alfalfa mixed). Ammoniation can s~hst~ntially increase its nutritional value. Although chaff is a known animal 25 feed, the current method of collecting is expensive and awkward (chaff wagons).
Collecting it as part of the harvesting process is much more efficient. The nutrients of the crushed weed seeds enhance the nutritional value of the chaff. The weed seeds are further destroyed as they will through the animal's digestive tract.
The removal of chaff and weed seeds and the reduction of grain loss on the fields will reduce weed and volunteer grain growth. Because weed and 5 volunteer grain growth is reduced pesticide and herbicide use is also reduced,which in turn reduces unwanted chemical environmental effects. The absence of chaff will aid zero-till planting. As it eliminates chaff rows, which inte,rere with seeding. It will also reduce fertilizer use, as it eliminates chaff clumps and rows on the field, which act as barriers for fertilizer to penetrate the soil. Chaff contributes 10 little nitrogen to soil, so its removal G~uses little loss in soil nutrition, compared to straw. The presence of chaff tends to i"le,rere with germination of subsequent crops. Furthermore the use of chaff-weed seed as cattle feed will result in increased availability of manure for fertilizer.
The system is designed to harvest all prairie crops including cereal 15 crops, oil seeds, and legumes, including mustard, lentils and beans, to support modern crop rotational methods.
As those skilled in the art would realize these preferred described details and materials and cor,lponents can be subjected to substantial variation, modification, change, alteration, and substitution without drre~ing or modifying the 20 function of the descl ibed embodiments.
Although embodiments of the invention have been described above, it is not limited thereto, and it will be apparent to per-~;Gns skilled in the art that numerous modifications and variations form part of the present invention insofar as they do not depart from the spirit, nature and scope of the claimed and described 25 invention.

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS

1. A cleaning unit for cleaning graff including grain and chaff, said cleaning unit comprising:
receiver means for receiving the graff;
grain cleaning means for separating the graff into grain and savings containing chaff and other material separated from the grain; and a mill for milling the savings.

2. A cleaning unit according to Claim 1 wherein the grain cleaning means include aspiration means for separating liftings from the graff.

3. A cleaning unit according to Claim 2 including a cyclone separator for receiving from the aspiration means a flow of air and liftings suspended in the air and for separating the liftings from the air.

4. A cleaning unit according to Claim 3 wherein the cyclone separator includes a liftings outlet and an airlock in the liftings outlet.

5. A cleaning unit according to Claim 2, 3 or 4 wherein the grain cleaning means include screening means for receiving graff from the aspiration means, said screening means including:
coarse screening means for screening the graff, to remove matter larger than the grain; and fine screening means for screening the graff to remove matter smaller than the grain.

6. A cleaning unit according to Claim 5 wherein the grain cleaning means include blower means for blowing air through the graff to remove matter lighter than the grain.

7. A cleaning unit according to any one of Claims 2 to 6 including means for mixing the liftings and other savings.

8. A cleaning unit according to any one of Claims 1 to 7 wherein the mill is a roller mill.

9. A cleaning unit according to any one of Claims 1 to 7 wherein the mill is a hammer mill.

10. A cleaning unit according to any one of Claims 1 to 9 including conveyor means for delivering grain from the cleaning unit to a grain storage bin.

11. A method of processing a harvested crop comprising graff containing grain, chaff and other residue, said method comprising:
separating the graff into grain and savings containing chaff and other material separated from the grain; and milling the savings.

12. A method according to Claim 11, wherein the step of milling the savings comprises compacting and crushing, the savings.

13. A method according to Claim 10, 11 or 12 wherein the step of separating of the graff comprises the steps of:
screening the graff to remove matter larger than the grain; and screening the graff to remove matter smaller than the grain.

14. A method according to Claim 13 wherein the step of separating of the graff further comprises blowing air through the graff to remove matter lighter than the grain.

15. A method according to any one of Claims 11 to 14 wherein the step of separating the graff comprises aspirating the graff to remove liftings.