Method and apparatus for in-field processing of vegetation

I claim:

1. A method for processing plant vegetation in a field to obtain therefrom a fibrous fraction and a liquid fraction, said method comprising the steps of:

harvesting the vegetation with mobile harvesting apparatus as it advances through the field,

separating the harvested vegetation on said mobile apparatus during harvesting to obtain from the plants a fibrous fraction and a liquid fraction,

fractionating said liquid fraction into a first component and a second component,

collecting said fibrous fraction and said first liquid component, and

applying said second liquid component onto said field as said apparatus advances, whereby the second liquid component is discarded during harvesting and processing of the vegetation.

2. The method according to claim 1 wherein said first component includes protein and said second component is substantially free of plant protein, and said fractionating step includes the step of heating said liquid fraction to a temperature within a predetermined range, admitting said heated liquid fraction to a holding tank, and holding said heated liquid fraction in said holding tank for a period of time sufficient to coagulate said protein, and removing said coagulated protein and said substantially protein free component from said holding tank.

3. The method according to claim 2 wherein said heating step includes the step of generating heat on said mobile apparatus, and passing said liquid fraction in heat transfer relation with said generated heat to cause said liquid fraction to be heated to said temperature.

4. The method according to claim 3 wherein said fractionating step includes the step of maintaining said holding tank substantially level as the vehicle advances to enable said coagulated protein to float on said deproteinized liquid in said holding tank.

5. The method according to claim 4 wherein said plant vegetation is alfalfa, and said temperature of said liquid fraction in said heating and holding step is at least about 80.degree. C.

6. The method according to claim 1 wherein said separating step includes the steps of macerating the harvested vegetation and pressing the macerated vegetation to obtain said fibrous and liquid fractions.

7. The method according to claim 6 wherein said macerating step includes the steps of admitting said vegetation into a rotatable die ring having a peripheral wall with orifices therein, rotating said die ring about its axis, and applying pressure against said vegetation in a radial direction as said die ring rotates to extrude the plants outwardly through the orifices.

8. The method according to claim 7 wherein said pressure in said pressure applying step is directed in diametrically-opposite directions at predetermined peripheral zones in said die ring, and said vegetation is admitted into said die ring at locations intermediate said zones.

9. The method according to claim 8 including the step of gathering the extruded vegetation around the periphery of said die ring, and displacing the extruded vegetation away from the periphery of the die ring as it rotates.

10. The method according to claim 6 wherein said pressing step includes the steps of feeding the plant vegetation between a pair of juxtaposed conical pressure members rotatable about axes intersecting one another at an obtuse angle, rotating the pressure members about their axes to squeeze the plant vegetation, collecting the liquid fraction at the bottom of the pressure members, and expelling the fibrous fraction from between the pressure members as they rotate about their axes.

11. Apparatus for field processing vegetation, comprising:

a vehicle adapted to travel through a field of vegetation,

means carried by said vehicle for harvesting the vegetation as the vehicle advances,

means carried by said vehicle for cooperating with said harvesting means to separate the harvested vegetation into a fibrous fraction and a liquid containing a plant protein composition and other compositions,

means carried by said vehicle for cooperating with said separating means to fractionate said liquid fraction into a first component containing said plant protein composition and a second substantially protein free component containing said other compositions,

means movable with said vehicle for collecting said fibrous fraction and said plant protein composition, and

means carried by said vehicle for applying said other compositions onto the field as the vehicle advances,

whereby the second liquid component is discarded during harvesting and processing of the vegetation.

12. Apparatus according to claim 11 wheren said fractionating means includes means on said vehicle for generating a source of heat, means for flowing said liquid fraction in heat transfer relation with said heat source, holding tank means for receiving said heated liquid fraction and thereby to afford coagulation of said protein, and means connected to said holding tank to remove coagulated protein and the substantially protein free liquid from said holding tank.

13. Apparatus according to claim 12 wherein said holding tank means includes a support structure, a vessel carried by said support structure, and gimbal means mounting said vessel in said support structure to afford pivotal movement of said vessel about axes disposed transversely and longitudinally relative to the path of movement of the vehicle, whereby the vessel is maintained substantially level during pitch and roll motion of the vehicle to afford separation of said coagulated protein from said deproteinized liquid.

14. Apparatus according to claim 12 wherein said deproteinized liquid applying means includes a manifold extending transversely below said vehicle, a plurality of spray heads depending from said manifold in spaced relation therealong, and conduit means connecting said holding tank means to said manifold.

15. Apparatus according to claim 11 wherein said separating means includes a macerator for shredding said harvested vegetation, a dewatering press associated with said macerator for expressing said liquid fraction from said fibrous fraction, and means connected between said macerator and said dewatering press for conveying said macerated vegetation from said macerator to said press.

16. Apparatus according to claim 15 wherein said macerator includes a die ring having a peripheral wall with a plurality of orifices extending outwardly therethrough, frame means supporting said die ring, bearing means around the periphery of said die ring wall mounting said die ring for rotation relative to said frame means, roller means in said die ring, means mounting said roller means for rotation in close proximity with said die ring wall, means for rotating said roller means, and means coupling said roller means to said die ring for causing said die ring to rotate with said roller means, whereby vegetation fed into the die ring is extruded through the orifices upon rotation of the rollers and die ring.

17. Apparatus according to claim 16 wherein said roller means includes a pair of rollers rotatable about axes parallel to the rotational axis of said die ring, said roller mounting means including bearing means mounted at diametrical locations to said frame means, and said coupling means including a spur gear rotatable with each roller and a ring gear rotatable with said die ring and engaging each spur gear, whereby rotation of the rollers causes the die ring to rotate in synchronism therewith.

18. Apparatus according to claim 17 including a conduit and blower assembly connecting said harvesting means to said macerator, and distributor means connecting said conduit to said macerator for charging harvested plants into said die ring at diametrical locations ahead of said rollers.

19. Apparatus according to claim 18 wherein said macerator includes a shroud surrounding said die ring, means providing an outlet in said shroud below said die ring, and impeller means disposed in said shroud and operable in response to rotation of said die ring to displace macerated plants toward said outlet.

20. Apparatus according to claim 15 wherein said dewatering press includes a pair of juxtaposed conical pressure members, frame means mounting said pressure members for rotation about obtusely-intersecting axes with their conical surfaces in confronting relation to provide a wide gap above their axes for receiving harvested vegetation and to provide a narrow gap below said axes for compressing the vegetation, deflector vane means disposed between said pressure members to expel pressed vegetation from between said pressure members upon rotation thereof, pan means disposed below said pressure members to collect liquid expressed from said vegetation, and means for rotating said pressure members about their axes.

21. Apparatus according to claim 20 wherein said pressure member mounting means includes a frame assembly having base means, a pair of strut assemblies projecting upwardly from said base means, a bearing extending around each pressure member inwardly adjacent its periphery, means mounting said bearing intermediate said pressure member and its associated strut assembly, hinge means mounting at least one strut assembly to pivot relative to said base means, and tie rod means releasably connecting the strut assemblies to maintain said pressure members in said operating relation while enabling said strut assembly to pivot and thereby afford access to the interior of said dewatering press.

22. Apparatus according to claim 21 wherein said pressure member rotating means includes a motor mounted to said strut assembly adjacent the periphery of each pressure member, a rotor mounted to said motor, drive means mounted on said pressure member adjacent its periphery, and means mechanically coupling said rotor to said drive means.

23. Apparatus according to claim 21 wherein each pressure member has means in its tapered surface for channeling fluid to its outer periphery, and including screen means overlying the tapered surface to prevent plant matter from clogging said channeling means.

Description Submit all comments and votes

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for field-processing vegetation. More particularly, the present invention relates to methods and apparatus for field-processing green-plant vegetation to obtain plant protein and fiber and a deproteinized liquid which is simultaneously discarded on the field.

BACKGROUND OF THE INVENTION

Dehydrated alfalfa is used as a supplement in livestock feed. The dehydrated alfalfa is customarily obtained by a process which involves harvesting alfalfa, hauling the harvested alfalfa to a centrally-located processing plant, heating the alfalfa at the plant to evaporate moisture therefrom, and then pelletizing the alfalfa. The alfalfa is usually dehydrated in rotary kilns which are heated by the combustion of fossil fuels such as oil or natural gas. A significant amount of thermal energy is required to dehydrate the alfalfa in this manner. Hence, with increasing constraints on the supply of fossil fuels, it should be apparent that the cost to produce dehydrated alfalfa by this process will continue to bear a direct relation to the cost of fuel.

Conventionally, alfalfa to be dehydrated is harvested by a self-propelled vehicle which cuts the alfalfa and collects the same in a hopper carried on the vehicle or in a trailer towed behind the vehicle. Although this procedure has the advantage of minimizing mechanical handling of the alfalfa in the field, it requires a substantial amount of energy simply to haul the relatively heavy, moisture-laden alfalfa to the processing plant. Also, the restrictions on the physical size of vehicles which can be used to haul alfalfa on the roads makes it desirable for the alfalfa to be compacted as much as possible for hauling in order to minimize the number of trips required to transport a given weight of alfalfa from the field to the processing plant.

The amount of moisture in the alfalfa can be reduced by sun-drying or field-wilting techniques. These techniques involve cutting the alfalfa, tedding the alfalfa, and gathering the alfalfa after it has dried to the desired moisture level. Although this procedure utilizes free solar energy to evaporate moisture from the alfalfa, solar energy does not provide a reliable source of heat because of the vagaries of the weather. Moreover, this technique is also less efficient since it involves greater mechanical handling of the alfalfa and hence more labor than the conventional procedure.

It is known that mechanical handling of dried alfalfa can cause substantial field losses of valuable plant matter. For instance, as the alfalfa dries, its leaves become brittle. Brittle leaves are easily shattered by mechanical manipulation. As much as 10-20% of the alfalfa plant may be lost from mechanical handling. Also, 5-10% of the dry plant matter can be lost by respiration after cutting. Since the leaves are an important part of the alfalfa plant containing the most protein and the least fiber, it should be apparent that these losses should be avoided where possible.

In addition to the losses due to mechanical handling, sun-drying of alfalfa is known to cause a deterioration in the carotene and xanthophyll content of the alfalfa. These components, together with protein, are normally guaranteed in the analysis of dehydrated alfalfa. Accordingly, it should be apparent that a process whereby a high-quality dehydrated alfalfa product can be produced efficiently is highly desirable.

In recent years, some experimental work has been conducted to demonstrate the practicality of processes for extracting protein concentrates from the alfalfa plant. In these processes, harvested alfalfa is transported to a processing plant where the alfalfa is macerated and pressed to separate the alfalfa into a fibrous fraction and a liquid fraction. The fibrous fraction is retained and dehydrated or used as ensilage, etc. The liquid fraction is heated to a predetermined temperature to cause the plant protein contained therein to coagulate and form a cheeselike curd which floats on a whey or brown juice. The curd is rich in protein, low in fiber content, and high in xanthophyll and carotene. The curd is, therefore, economically valuable as a feed supplement for non-ruminant animals, and especially poultry. For a more detailed description of the above processes, reference is made to the following articles:

Crops and Soils Magazine, August-September, 1973, pages 12-13; Report of Fifth Annual Alfalfa Symposium held on Apr. 8, 1975, in Hershey, Pa.; Technical and Ergonomic Aspects of the Production of Alfalfa Silage by Fractionation, paper given at the Eighth International Congress of Agricultural Engineering held in The Netherlands on September 23-29, 1974, by Bouhn, Koegel, Schirer, and Fromin; and a Report entitled On the Farm Production of Alfalfa Juice Protein by Bouhn and Koegel presented at the American Society of Agricultural Engineers Plant Juice Seminar at Madison, Wisconsin on Apr. 27, 1974.

Although the processes described in the above articles are capable of extracting valuable components from alfalfa, they have several limitations. For instance, the processes are performed at a stationary plant location. Thus, the alfalfa (and the water contained therein) must be hauled to the plant, and this involves the expenditure of substantial amounts of labor and energy. In addition, these processes generate substantial quantities of deproteinized brown juice or whey which must be discarded in an environmentally-satisfactory manner.

OBJECTS OF THE INVENTION

With the foregoing in mind, it is a primary object of the present invention to provide a novel method and apparatus for enabling high-quality dehydrated alfalfa and alfalfa silage to be produced efficiently.

Another object of the present invention is to provide an improved method and apparatus for producing dehydrated alfalfa which is rich in carotene and xanthophyll.

A further object of the present invention is to provide a method and apparatus for enabling high quality dehydrated alfalfa to be produced substantially independent of weather conditions.

It is another object of the present invention to provide a unique method and apparatus for field-processing alfalfa to obtain a fibrous fraction and liquid fraction having a protein component which is retained and a deproteinized liquid component which is applied onto the field during processing.

A still further object of the present invention is to provide alfalfa-processing apparatus which is sufficiently compact and light in weight as to be capable of being carried on a self-propelled vehicle.

Another object of the present invention is to provide an improved macerator which is of simple but rugged construction and which functions to achieve effective cell rupture of legumes such as alfalfa.

As a still further object, the present invention provides an improved dewatering press which is light in weight, compact and which is capable of expressing a maximum amount of liquid from green plant vegetation such as alfalfa or other legumes.

SUMMARY OF THE INVENTION

More specifically, the present invention provides a method and apparatus for in-field processing of green plant vegetation, including legumes such as alfalfa. The apparatus performs a method comprising the steps of harvesting the alfalfa with a self-propelled harvester, processing the harvested alfalfa in equipment carried on the harvester to obtain a liquid fraction and a fibrous fraction, separating the liquid fraction into a protein-rich curd component and a deproteinized whey component rich in growth-promoting chemical compounds by heating the liquid fraction and holding the heated liquid in a fractionating tank, collecting the fibrous fraction and the curd, and applying the whey onto the field as the vehicle advances to fertilize the field during harvesting and processing of the alfalfa.

The present invention provides specially designed rotary extrusion apparatus for macerating the alfalfa plants. The extrusion apparatus comprises a frame, a die ring carried by the frame, bearing means supported by the frame around the periphery of the die ring to mount the die ring for rotation relative to the frame, roller means disposed in the die ring for extruding alfalfa outwardly through peripheral orifices in the die ring, means for rotating the roller means, and means coupling the die ring to the roller means so that the die ring rotates in synchronism with the roller means. A shroud surrounds the die ring to collect macerated alfalfa, and impeller means between the shroud and the die ring causes the macerated alfalfa to be discharged from an outlet in the shroud as the die ring rotates.

The present invention also provides an improved dewatering press for separating the macerated alfalfa into fibrous and liquid fractions. The dewatering press comprises a pair of conical pressure members, means mounting the pressure members for rotation about obtusely-intersecting horizontal axes, means to rotate the pressure members, deflector vane means disposed between the pressure members operable to expel alfalfa fiber from between the press members as they rotate, and pan means extending around the lower periphery of the pressure members to collect liquid expressed from the alfalfa. The pressure member mounting means includes a pair of upstanding strut assemblies located outboard of the pressure members, bearing means mounted between each strut assembly and each pressure member, hinge means pivotally connecting the bottoms of the strut assemblies to a base to afford downward pivotal movement of the pressure members away from one another, and tie bar means extending across the tops of the pressure members for releasably connecting the strut assemblies together. Screen means and channel means are provided on the confronting surfaces of the pressure members to enhance the pressing action.

These and other objects, features and advantages of the present invention should become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of apparatus which is particularly suited for practicing the method of the present invention;

FIG. 2 is a plan view of the apparatus illustrated in FIG. 1;

FIG. 3 is an enlarged sectional view of rotary extrusion apparatus for macerating plants;

FIGS. 4 and 5 are enlarged sectional views taken on lines 4--4 and 5--5, respectively, of FIG. 3;

FIG. 6 is a greatly-enlarged fragmentary sectional view of an orifice through which plant material is extruded in the extrusion apparatus;

FIG. 7 is an enlarged front elevational view of a dewatering press particularly suited for use in separating macerated plant material into liquid and fibrous fractions;

FIG. 8 is a side elevational view of the dewatering press taken on line 8--8 of FIG. 7;

FIG. 9 is a sectional view of the dewatering press taken on line 9--9 of FIG. 7;

FIG. 10 is a fragmentary sectional view taken on line 10--10 of FIG. 9; and

FIG. 11 is a greatly-enlarged sectional view taken on line 11--11 of FIG. 8.

Referring now to the drawings, FIGS. 1 and 2 illustrate apparatus 10 which is particularly suited for harvesting and field-processing green plant vegetation including legumes such as alfalfa 11 but which may be used to harvest other green plant forage crops such as timothy, clover, and mixtures of these and other plants commonly called hay. The apparatus 10 comprises a conventional self-propelled vehicle 13 having an engine which is housed in an enclosure 14 and which supplies power through a suitable transmission to drive high-flotation front and rear wheels 16. The wheels 16,16 are steered by an articulated steering system controlled from a driver's compartment 15 located on the front of the vehicle 13. A crop-harvesting header 18 is mounted on the front of the vehicle for cutting the alfalfa 11 as the vehicle 13 advances in the direction indicated by the arrow in FIG. 1.

A typical vehicle having a structure similar to the above is manufactured by Champion Products, Inc., of Eden Prairie, Minn. and is sold under its model designation "4-X-4 Articulated."

As best seen in FIG. 2, the header 18 extends transversely across the front of the vehicle 13. The header 18 is designed to cut and convey the alfalfa 11 to a blower-chopper 19 located on the vehicle 13 behind the header 18 and alongside the driver's compartment 15. The blower-chopper 19 functions to convey the alfalfa rearwardly away from the header 18.

In the conventional forage-crop harvester, the alfalfa plants harvested by the header 18 are blown directly into a trailer 20 towed behind the vehicle 13. Thus, when the standing crop of alfalfa 11 has a high moisture content, such as after a rain, the alfalfa collected in the trailer 20 contains a significant amount of water. Heretofore, it was necessary to transport the relatively-heavy, bulky, moisture-laden alfalfa to the dehydrating plant where a substantial amount of thermal energy was required to evaporate the water from the alfalfa.

In accordance with the present invention, the apparatus 10 harvests and field processes alfalfa to minimize the energy required to haul the alfalfa and to dehydrate the same. Specifically, the apparatus 10 is designed to separate from the harvested alfalfa plants a significant amount of the water contained therein and simultaneously to apply the water (which contains chemical compounds valuable as plant fertilizers) directly onto the field.

These advantages are realized by the method of the present invention which comprises the steps of: advancing the mobile harvesting apparatus through a standing crop of alfalfa, harvesting the alfalfa with the apparatus as it advances, separating the harvested alfalfa into a fibrous fraction and a liquid fraction, fractionating the liquid fraction into a first component which has a protein value and a second component which has a fertilizer value, collecting the fibrous fraction and the protein value component of the liquid fraction, and applying the fertilizer value component of the liquid fraction onto the field as the apparatus advances. Thus, the fibrous fraction of the harvested alfalfa is lighter in weight and packs more densely so that it is less expensive to transport; the alfalfa fiber can be dehydrated with less energy; and the liquid fraction by-product is discarded on the field in an economically and environmentally satisfactory manner.

The separating step is performed in a specially-designed rotary extruder or macerator 21 which shreds the harvested alfalfa and a dewatering press 22 which presses the macerated alfalfa to separate the same into a fibrous fraction and a liquid fraction.

As best seen in FIG. 1, the macerator 21 is carried by the vehicle 13 at an elevated level behind the driver's compartment 15. The havested alfalfa is supplied to the macerator 21 through a tube or conduit 26 which is connected to the blower-chopper 19. As best seen in FIG. 2, the tube 26 has diverging leg portions 26a and 26b which turn downwardly into the top of the macerator 21 to provide means for distributing the alfalfa at diametrical locations in the macerator 21.

The macerated alfalfa emerges from the bottom of the macerator 21 and enters a hydraulically-powered screw conveyor or auger 23 which conveys the macerated alfalfa to the dewatering press 22 located on the side of the vehicle 13 opposite the macerator 21.

The dewatering press 22 has an inlet at its upper end for receiving the macerated alfalfa supplied by the conveyor 23. The alfalfa advances clockwise in the press and is squeezed therein. Liquid expressed from the alfalfa is collected in a drain 30 at the bottom of the press 22. The pressed alfalfa fiber is expelled from the press 22 and into a blower 31 mounted behind the press 22. An upwardly and rearwardly curved chute 32 is connected to the outlet of the blower 31 to direct the pressed fiber rearwardly into the trailer 20 for collection therein.

The structure and operation of both the macerator and the dewatering press will be described more fully hereinafter. It is sufficient to note at this juncture that the macerator functions to rupture the cells of the leaves and stalks of the alfalfa plant by extruding them through shaped orifices. The dewatering press functions to separate the alfalfa plants into liquid and fibrous fractions by applying relatively high pressures to the macerated plants for a sufficient period of time to allow the liquid to flow by gravity from the plants.

The liquid fraction collected at the bottom of the dewatering press 22 is separated into a first liquid component having a protein value and a deproteinized second liquid component having a fertilizer value. To this end, the drain 30 of the press 22 is connected by a conduit 38 to a pump 39 which is connected by a conduit 40 to a heat-exchanger 41. The heat exchanger 41 is connected by a conduit 42a and flexible coupling 42b to a holding or fractionating tank 44 located on the rear of the vehicle 13 behind the macerator 21 and alongside the blower 31. The heat exchanger 41 is connected to means on the vehicle 13 for generating a source of heat, such as the hydraulic fluid which drives the various hydraulic motors and actuators employed on the vehicle. If desired, heat may be obtained directly from the cooling system of the engine. The liquid fraction may also be heated by injecting steam into the liquid fraction. The steam may be generated in the cooling system of the engine and supplied, for example, from the engine radiator, with suitable provision being made to carry make-up water on the vehicle.

The heat exchanger 41 and the fractionating tank 44 should have a sufficient capacity to heat about 4500 gpm of the liquid fraction to a temperature of about 80.degree. C. and to maintain the liquid fraction at that temperature for about 2-4 minutes. The heating which occurs in the heat exchanger 41 and the holding which occurs in the fractionating tank 44 causes the proteins contained in the liquid fraction to coagulate. The coagulated proteins form a bright green curd having the texture of cottage cheese. Because of its low density, the curd rises to the surface of the liquid or whey contained in the fractionating tank, and this permits the curd to be separated from the underlying liquid by conventional skimmers in the tank 44. If desired, a centrifugal separator may be utilized satisfactorily.

After separation from the whey, the curd is fed into a storage container 46 through a flexible coupling 47. Preferably, the storage container 46 is maintained under a slight vacuum by a pump 48 to draw the curd from the fractionating tank 44.

To facilitate separation of the curd from the whey, it is desirable to maintain the liquid fraction relatively quiescent in the fractionating or holding tank 44. To this end, the fractionating tank or vessel 44 is mounted to the vehicle 13 by gimbal means which enables the fractionating tank 44 to pivot about horizontal axes extending both longitudinally and transversely with respect to the path of movement of the vehicle 13. As best seen in FIG. 2, the illustrated gimbal mounting means includes a pair of upstanding A-frame members 49 which mount bearings 50 at their upper ends. The bearings 50 rotatably receive trunnions 51 which extend transversely outward from a rectangular frame 52. The frame 52 mounts a pair of bearings 53 which receive trunnions 54 extending longitudinally outward from the fractionating tank 44. With this structure, the fractionating tank 44 is capable of pivoting about intersecting horizontal axes provided by the trunnions 51 and 54 in response to pitch and roll motion of the vehicle 13. As a result, the liquid contained in the fractionating tank 44 is maintained substantially level as the vehicle 13 advances, thereby facilitating gravitational separation of the curd from the whey.

The residual liquid fraction or whey contained in the fractionating tank 44 includes a chemical compounds which are known to promote plant growth. For example, standing alfalfa containing 80% moisture and 20% protein can yield a whey consisting of 94% water and 6% dry matter, by weight. The dry matter is composed of chemical compounds of the elements nitrogen, phosphorous, potassium, and other growth-promoting trace element compounds. As used herein, the term fertilizer value refers to these chemical compounds.

The deproteinized liquid or whey is applied onto the field as the alfalfa is being harvested and processed. For this purpose, applicator means is provided on the vehicle 13 for spreading the whey on the field. In the illustrated embodiment, the whey is applied by a sprayer assembly 56 which is mounted beneath the vehicle 13. As best seen in FIG. 2, the sprayer assembly 56 comprises an elongated manifold 57 and a series of spray heads 58 depending from the manifold 57 in spaced relation therealong. The manifold 57 is connected to the bottom of the fractionating tank 44 by a conduit 59 and a flexible coupling 55. Although the whey will flow by gravity from the fractionating tank 44 to the spray heads 58, it may be desirable to install a pump in the conduit 59 between the tank 44 and the manifold 57 to increase the spraying pressure at the spray heads 58. In the present gravity flow system, the manifold 56 has a length which is substantially coextensive with the width of the harvesting header 18 so that the whey is spread substantially uniformly across the width of the swath cut by the harvesting head 18.

The alfalfa plants are shredded thoroughly and efficiently by causing them to be forced through a series of relatively small openings in the rotary extrusion apparatus or macerator 21 which functions to rupture the cells of the alfalfa plants. To this end, the macerator 21 includes a rotary die ring 60 having a cylindrical peripheral wall 61 and a bottom wall 63 extending transversely across the lower end of the peripheral wall 61. The peripheral wall 61 has a series of extrusion orifices 62 which extend radially outward through the wall 61. The die ring 60 is open at its upper end to afford downward infeeding of the alfalfa plants into its interior.

The alfalfa plants are forced through the orifices 62 by pressure-applying means provided at diametrical locations in the die ring 60. In the present instance, the pressure is applied by roller means which comprises a pair of hollow rollers 65 mounted at diametrical locations in the die ring 60 for rotation about axes A.sub.2 and A.sub.3 extending parallel to the central axis A.sub.1 of the die ring 60. Preferably, each roller 65 has a central shaft 65a which projects upwardly beyond the upper end of the die ring 60. The shaft 65a mounts a pair of axially-spaced circular plates 65b, and a cylindrical wall 65c surrounds the circular plates 65b. As best seen in FIG. 5, a plurality of axially-extending grooves or serations 65d are spaced apart around the periphery of each roller wall 65c to provide an effective means for gripping the plants. Each roller 65 is substantially as high as the peripheral wall 61 of the die ring 60, and the outside diameter of each roller 65 is slightly less than the radius of the die ring 60 measured from its axis A.sub.1 to the inside of the die ring wall 61. This dimensional relation provides a gently tapered nip 66 between the periphery of each roller 65 and the inside of the die ring wall 61. The tapered nip cooperates with the roller gripping means to facilitate the gripping of alfalfa plants by the rollers 65 and the feeding of the plants between the rollers 65 and the die ring 60 as they rotate in the directions indicated by the arrows in FIG. 4. This enables each roller 65 to cooperate with the die ring wall 61 to apply pressure in a radial direction to alfalfa plants interposed therebetween for extruding the alfalfa plants outwardly through the orifices 62.

The die ring 60 and the rollers 65 are rotatably supported by means of a frame 67. In the illustrated embodiment, the frame means 67 includes a plate 67a and thrust bearing means 68 rotatably mounting the die ring 60 to the frame plate 67a. As best seen in FIG. 3, the frame plate 67a has a circular central aperture 67b which surrounds an outwardly-extending peripheral flange 61a on the die ring wall 61. The bearing 68 has an inner ring 68a bolted onto the top of the die ring flange 61a, and the bearing 68 has an outer ring 68b bolted onto the top of the frame plate 67a.The bearing 68 has a plurality of rolling elements 68c interposed at an angle between the inner and outer rings 68a and 68b to enable the bearing to accept both radial and thrust loads. Thus, the die ring 60 is rotatably supported around its upper periphery in the frame 67.

The rotation of the die ring 60 is synchronized with the rotation of the rollers 65. To this end, gearing means is provided to couple the die ring 60 and the rollers 65 so that they have substantially equal peripheral velocities at the diametrical die ring extrusion zones Z.sub.1 and Z.sub.2. As seen in FIG. 5, the gearing means includes a spur gear 70 mounted on the roller shaft 65a above the upper end of the roller 65, and a ring gear 71 intergral with the inner ring 68a of the bearing 68. The ring gear 71 has internal teeth which mesh with the external teeth on each spur gear 70. The pitch diameter of each spur gear 70 corresponds substantially to the outside diameter of each roller 65, and the pitch diameter of the die ring gear 71 corresponds substantially to the inside diameter of the die ring 60. Thus, ahead of the nip 66 between the roller 65 and the die ring 60, the peripheral speed of the roller 65 is greater than the peripheral speed of the die ring wall 61, while at the zone of maximum outward extrusion (between the die ring wall 61 and the roller 65) the peripheral speed of the die ring wall 61 and each roller 65 is substantially equal. This relation promotes infeeding of the plant matter into the extrusion zones Z.sub.1 and Z.sub.2 (FIG. 4) and extrusion of the vegetation.

The plant matter to be macerated is distributed uniformly in the die ring 60. For this purpose, distributor means is provided to feed the plant matter into the die ring 60 at diametrical locations ahead of the rollers 65. In the illustrated embodiment, the distributor means includes a circular cover plate 72 which overlies the upper end of the die ring 60 and which is spaced from the die ring 60 by a peripheral spacer ring 74. The cover plate 72 and the spacer ring 74 are removably secured to the frame 67 by a series of circumferentially-spaced bolts 73 which depend through the spacer ring 74 and into the frame plate 67a. A pair of inlet tubes or ferrules 75 are provided at diametrical locations in the cover plate 72 and are offset 90.degree. with respect to the rollers 65. The inlet ferrules 75 are adapted to be connected to the downturned ends of the legs 26a and 26b of the feed conduit 26 (See FIG. 2). Preferably, the coverplate 72 is provided with several openings 72b to afford the escape of air entrained in the alfalfa from the interior of the die ring. Thus, plant matter to be extruded in the die ring 60 is fed downwardly through the ferrules 75 and is distributed substantially evenly in the die ring 60 at locations ahead of the rollers 65 where the plant matter can be readily gripped by the rollers 65.

A substantial amount of pressure is applied to the plant matter to extrude it through the orifices 62 in the die ring wall 61. In order to enable the rollers 65 to apply the pressure continuously, bearing means is provided above the cover plate 72 to mount the rollers 65 for rotation in the die ring 60. As best seen in FIG. 3, the roller shafts 65a, 65a project upwardly through a pair of holes 72a in the cover plate 72, and the bearing means is mounted in a recess provided by mounting means which protrudes upwardly from the topside of the cover plate 72 adjacent each aperture 72a. In the present instance, the mounting means includes a short upwardly-protruding mounting plate 76 welded to the topside of the cover plate 72 adjacent each aperture 72a and a long upwardly-protruding mounting plate 77 welded to the topside of the cover plate 72 on the side of the aperture 72a opposite the short mounting plate 76. The long mounting plate 77 is reinforced by a pair of gusset plates 78 which extend outwardly toward the edge of the cover plate 72. The upper end of the roller shaft 65a projects upwardly intermediate the mounting plates 76 and 77 and is received in axially-spaced pillow blocks 79 and 80 which are bolted to the mounting plates 76 and 77, respectively. Preferably, shims 81 and 82 are interposed between the bases of the pillow blocks 79 and 80 and the mounting plates 76 and 77 in order to provide means for adjusting the spacing between the outer periphery of the rollers 65 and the inner periphery of the die ring wall 61.

In order to provide the power to drive the die ring 60 and the rollers 65, means is provided to rotate each roller 65. In the illustrated embodiment, the rotating means includes a conventional hydraulic motor 82 connected to the upper ends of each roller shaft 65a. The hydraulic motors 82 are connected to the frame 67 by suitable brackets (not shown). Preferably, each hydraulic motor 82 is of about 25 horsepower and rotates at a constant speed of 200 rpms. Thus, with the gearing means coupling the rollers 65 to the die ring 60, the die ring 60 rotates about its axis A.sub.1 at a speed of about 100 rpms. This speed has the effect of causing the alfalfa fed into the die ring 60 to be forced outwardly against the die ring wall by centrifugal force. The macerator 21 has a capacity of macerating 60,000 lbs./hr. of freshly-harvested alfalfa.

The macerated plant matter expelled from the die ring 60 is collected by means of a shroud 85 which depends from the frame plate 67a and surrounds the die ring 60. As best seen in FIG. 3, the shroud 85 has a cylindrical upper wall 85a which surrounds the peripheral wall 61 of the die ring 60 and an outturned flange 85b which is bolted to the underside of the frame plate 67a. The shroud 85 has a funnel-shaped lower wall 85c which depends from the cylindrical wall 85a and terminates in a central outlet 85d coaxial with the rotational axis A.sub.1 of the die ring 60. Thus, plant matter discharged from the die ring 60 is collected in the shroud 85 and is discharged from the common outlet 85d.

The shredded plant matter is displaced positively in a downward direction in the shroud 85 as the macerator 21 operates. To this end, impeller means is provided in the shroud 85 and is rotatable in response to rotation of the die ring 60. In the present instance, the impeller means includes a pair of blades 87 and 88 which sweep across the inner surface of the shroud 85 as the die ring rotates. As best seen in FIGS. 3 and 5, the blades 87 and