Patent Publication Number: US-2023141301-A1

Title: Weed Seed Destruction

Description:
This application continuation application of application Ser. No. 16/639,198 filed Feb. 14, 2020 which is a National Phase application under 35 USC 371 of PCT Application PCT/CA2018/051120 filed Sep. 11, 2018 which is a continuation in part of application Ser. No. 15/701,096 filed Sep. 11, 2017. This application claims the benefit under 35 USC 119 (e) of Provisional application 62/763,112 filed Feb. 1, 2018. 
    
    
     This invention relates to a weed seed destructor which can be attached to a combine harvester so that weed seeds in the discharged chaff can be devitalized before being spread onto the ground. 
     BACKGROUND OF THE INVENTION 
     Combine harvesters harvest cereal grain crops, such as wheat, oats, rye, barley, corn, soybeans and flax. Grain and straw are separated in a combine harvester. Following the separation process, waste straw and chaff is supplied to a chopper for shredding and distributing back over the field in an even spread pattern. 
     During the harvesting process weed seeds and grain seed are discharged with the residue into the chopper and spread back onto the field. The combine is then effectively acting as a seeder to evenly spread the seed back onto the field. In a number of areas of the world herbicides are used heavily to control the weed seeds however this has led to weed seed that has become resistant to the herbicide. Grain seed has been developed to be resistant to specific herbicides, which depending on crop rotations can be a problem for subsequent crop. 
     It is known that if the seed can be removed or destroyed before the combine spreads it back onto the field the cycle can be stopped. Research has shown that, with three consecutive cycles of weed and grain removal, significant reductions in herbicide can be obtained providing huge saving for farmers. 
     One recent approach is shown in WO 2014/127408 published August 28th 2014 and assigned to Grains Research Development Corporation Australia which shows that a plurality of impacts at relatively high speed of the seeds with a stationary object causes breakdown of the seed sufficient to prevent germination. Thus they have developed a cage mill which is integrally mounted inside the combine harvester so as to receive waste material (discarded seeds and chaff) from the sieve. The cage mill assembly includes at least one rotating ring carrying a plurality of blades and a series of outer stationary rings or fixed blades. Thus the seeds are accelerated outwardly by escaping centrifugally from the rotating blades into the surrounding stationary blades of the outer rings where a series of impacts occur as the seeds move outwardly into and through the fixed blades. The seeds are released outwardly under the centrifugal force from the stationary blades and escape outwardly into a peripheral channel for discharge. 
     The document shows evidence that four impacts at relatively high speed are sufficient to cause the required breakdown of the seeds, for example to obtain a 95% kill rate. 
     However the cage mill shown is large and complex with numerous rings running in opposite directions. Should a rock, or other hard material enter the mill, the entire cage mill would need to be replaced. Thus the system may function to destroy the seeds but has practical difficulties as it is without consideration of other obstacles passing through the assembly. The assembly runs at a very high rotational speed, so the precision in manufacturing is critical. Although this is believed that this arrangement is closer to commercialization a number of problems remain with the design. 
     U.S. Pat. No. 3,448,933 (Roy) issued Jun. 10, 1969 describes a cone style grinding shear mill used to process weed seed. All excess chaff and weed seed is processed by the unit. However it is a permanently fixed grinder without a means to bypass material other than residue. It would also allow passage of small fine seeds as it would need to be set to the average seed size to allow adequate throughput. 
     U.S. Pat. No. 5,059,154 (Reyenga) issued Oct. 22, 1991 discloses a pair of rollers to mill seeds smaller than grain that are in the clean grain auger. This does not address seeds thrown over the back of the sieve and would not work if placed behind the sieve as today&#39;s combines the chaff stream is often 6 inches thick which would cushion the seeds and allow the spread of live seed back onto the field. 
     In AU Published Application 2001/038781 an additional sieve is added to remove more of the chaff before milling, and separate the weed seed from the grain. However this is not practical with today&#39;s combines. All combines throw out some grain and farmers want the herbicide tolerant grain removed as well. 
     U.S. Pat. No. 8,152,610 (Harrington) issued Apr. 10, 2012 discloses an arrangement which processes all the chaff coming off of the sieves and blows it to a trailing cart to pulverize all of the residue. The cart requires a second engine running in the dust of the combine and the mill requires a significant amount of power to pulverize and discharge the residue back onto the field. The cage mill disclosed is large and complex with numerous rings running in opposite directions. Again, the rings have not removable parts so should a rock, or other hard material enter it the entire cage mill would need to be replaced. The cost of this system will limit its commercial viability. 
     The term weed seed destruction used herein is used somewhat colloquially in that the seeds are not annihilated but are devitalized or rendered so that they cannot germinate. It will of course also be appreciated that not necessarily each and every seed is destroyed but that the intention is that a significant number will be incapable of germination so as to reduce the number of emerging seeds in the growing season. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a combine harvester comprising: 
     a separation system for separating from harvested crop a first material comprising straw and a second material comprising chaff and weed seeds; 
     a weed seed devitalizer; 
     and a controller configured to: 
     receive data indicating forthcoming weed seeds; and 
     output control signals controlling operation of the weed seed devitalizer based on the data. 
     According to the invention there is provided a combine harvester comprising: 
     a separation system for separating from harvested crop a first material comprising straw and a second material comprising chaff and weed seeds; 
     a weed seed devitalizer; 
     and a controller configured to: 
     receive data relating to a GPS map of a weed problem in an area to be harvested; and 
     output control signals controlling operation of the weed seed devitalizer based on the data. 
     Also disclosed herein there is provide an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     at least one stator arranged at a location along the direction and comprising a stator support member and a plurality of stator portions mounted on the support member for engaging the weed seeds in the accelerated feed material; 
     wherein there is provided a generally horizontal shaft mounted on the housing and including a gear box for driving a generally upstanding drive shaft and wherein the rotor is mounted on the drive shaft on top of the horizontal shaft. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     at least one stator arranged at a location along the direction and comprising a stator support member and a plurality of stator portions mounted on the support member for engaging the weed seeds in the accelerated feed material; 
     wherein there is provided an inner stator and an outer stator coaxial therewith and at least one of inner and outer stators is adjustable to change the angular relationship therebetween; 
     and wherein the angular position of at least one of the stators is adjustable by a control linkage from a cab of the combine harvester. 
     Also disclosed herein there is provide an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     at least one stator arranged at a location along the direction and comprising a stator support member and a plurality of stator portions mounted on the support member for engaging the weed seeds in the accelerated feed material; 
     wherein each of the rotor blades includes a sharpened cutting edge radial to the axis. 
     Also disclosed herein there is provide an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     at least one stator arranged at a location along the direction and comprising a stator support member and a plurality of stator portions mounted on the support member for engaging the weed seeds in the accelerated feed material; 
     wherein the rotor also includes an additional blade element outside of the outer stator element. 
     Preferably in any of the above aspects the stator support member is cylindrical so as to surround the axis of the rotor and the stator portions are part cylindrical with each of the plurality of stator portions extending around a part only of the periphery of the support member. 
     Preferably in any of the above aspects there is provided a discharge opening between each stator portion and the next. 
     Preferably in any of the above aspects there are provided inner and outer coaxial cylindrical stators. 
     Preferably in any of the above aspects there are provided rotor components between the inner and outer stators. 
     Preferably in any of the above aspects each stator portion comprises a plurality of upstanding impact posts at spaced positions around the axis. 
     Preferably in any of the above aspects there is provided a plurality of the stator portions having different characteristics which can be selected for different weed seed sizes. 
     Preferably in any of the above aspects the stator portions are hard surface coated as a separate component from the support member. 
     Preferably in any of the above aspects each of the stator portions comprises mounting edges at angularly spaced ends of the portion for attachment to a rail of the support member. 
     Preferably in any of the above aspects the support member comprises a top and bottom ring around the axis of the rotor with a plurality of rails parallel to the rotor axis. 
     Preferably in any of the above aspects each of the stator portions comprises an angularly spaced row of deflector surfaces parallel to the rotor axis. 
     Preferably in any of the above aspects the stator includes a plurality of discharge openings at angularly spaced positions around the stator with the support member being angularly adjustable around the rotor axis to move the openings. 
     Preferably in any of the above aspects there is provided an inner stator and an outer stator coaxial therewith and at least one of inner and outer stators is adjustable to change the angular relationship therebetween. 
     Preferably in any of the above aspects the angular position of at least one of the stators is adjustable by a control linkage from a cab of the combine harvester. 
     Preferably in any of the above aspects the rotor comprises a hub carrying rotor blades defining said rotor surfaces where the blades are pivotally mounted about an axis parallel to the rotor axis so as to act as blades. 
     Preferably in any of the above aspects each of the rotor blades includes a sharpened cutting edge radial to the axis and a fan blade portion generally axial of the axis. 
     Preferably in any of the above aspects the rotor also includes an additional blade element outside of the outer stator element. 
     Preferably in any of the above aspects each of the additional blade elements includes a sharpened cutting edge radial to the axis and a fan blade portion generally axial of the axis. 
     Preferably in any of the above aspects each of the additional blade elements is located underneath the stator. 
     Preferably in any of the above aspects there are two rotors each mounted on a respective gear box at spaced positions along the horizontal shaft. 
     The invention herein can be used with many different types of stator in a multi-stage impact mill including round or flat surfaces and other obstacles which engage the material as it is carried by the rotor. Examples are shown in the above cited patent documents. In one example the stator includes perforated stator plates with an opening between each plate and the next. However the same constructions defined herein can be used with stator elements where the material passes between one obstacle or blade and the next in an array around the axis. 
     Preferably the support member is cylindrical so as to surround the axis of the rotor and the stator surface portions are part cylindrical. 
     Preferably the stator surface portions have a common axial dimension. 
     Preferably each of the plurality of stator surface portions extends around a part only of the periphery of the support member. 
     In one example there is provided a discharge opening between each stator surface portion and the next so that some of the material escapes through perforations in the stator surfaces and some escapes through a discharge opening. However many other styles and arrangement of the stator can be used. 
     Preferably there are provided at least two stators arranged as inner and outer coaxial cylindrical stators but there may be more stators. 
     Preferably there are provided rotor components between the inner and outer stators to assist in movement of the material between the stators and to carry the material around the inside surface of the outer stator to process the material. 
     In one embodiment, each stator surface portion comprises a plate which is perforated with an array of holes so that the material slides over the inner surface of the part cylindrical plate to interact with the holes. 
     Preferably a plurality of the stator surface portions having different characteristics which can be selected for different weed seed sizes. 
     Preferably the stator surface portions are hard surface coated as a separate component from the support member. In this arrangement, each of the stator surface portions comprises a frame and bars which can be hardened as a separate relatively small component using known processes. 
     For example each of the stator surface portions comprises mounting edges at angularly spaced ends of the portion for attachment to a rail of the support member. That is a simple construction of the stator surface portions is a r pair of sheet metal plates curved to provide the required part cylindrical shape with turned down end portions to act as mounting flanges with bars welded between to provide the impact surfaces. 
     Preferably the support member comprises a top and bottom ring around the axis of the rotor with a plurality of rails parallel to the rotor axis to allow each of the portions to be attached at angular spaced positions around the axis. 
     Preferably there is a seal created between the rotor and at least one stator ring to eliminate a pathway through the mill in which weed seeds can escape without contacting a stator surface 
     In another embodiment each of the stator surface portions comprises an angularly spaced row of deflector surfaces parallel to the rotor axis. 
     Preferably there is provided an inner stator and an outer stator coaxial therewith and at least one of inner and outer stators is adjustable to change the angular relationship therebetween. 
     Preferably the angular position of at least one of the stators is adjustable from the cab. 
     Preferably the rotor comprises a hub carrying rotor blades defining rotor surfaces where the blades are pivotally mounted about an axis parallel to the rotor axis so as to act as blades. 
     Preferably said stator and said one or more stator surfaces of the stator are arranged such that the weed seeds impact on said one or more stator surfaces and do not pass through the stator along said direction but instead are rebounded therefrom back toward the rotor and such that the weed seeds rebound back and forth between the rotor and the stator to provide a plurality of impacts on the accelerated feed material to destroy at least some of the weed seeds. 
     Preferably at least one of the rotor surfaces and/or at least one of the stator surfaces is arranged to pivot to a position to increase a spacing between the stator and rotor surfaces to allow the passage of foreign objects between the rotor and stator surfaces. 
     Preferably the rotational speed of the rotor is adjustable to change the number of impacts a seed encounters during its passage. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving from the location a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     a stator arranged at a location along the direction and including one or more stator surfaces for engaging the weed seeds in the accelerated feed material; 
     wherein the stator surfaces are movable in an adjustment movement so as to change the number of impacts caused to each weed seed. 
     Preferably the stator surfaces are movable in the adjustment movement about an axis parallel to the rotor axis. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving from the location a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     a stator arranged at a location along the direction and including one or more stator surfaces for engaging the weed seeds in the accelerated feed material; 
     wherein the stator surfaces are replaceable. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving from the location a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     a stator arranged at a location along the direction and including one or more stator surfaces for engaging the weed seeds in the accelerated feed material; 
     said stator and said one or more stator surfaces of the stator being arranged such that the weed seeds impact on said one or more stator surfaces; 
     wherein the rotor comprises a hub carrying rotor blades defining said rotor surfaces where the blades are pivotally mounted about an axis parallel to the rotor axis so as to act as blades. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds for use in a combine harvester where the combine harvester comprises a separation system for separating from harvested crop at a first discharge location a first material comprising straw and at a second discharge location a second material comprising chaff and said weed seeds, the apparatus comprising: 
     a straw chopper section comprising:
         a chopper housing arranged to receive from the first discharge location the first material containing straw;   a chopper rotor mounted in the chopper housing having a plurality of chopping blades for chopping the straw for discharge from the first housing component;   and a spreading device for receiving the straw discharged from the chopper housing and spreading the discharged straw to rear and sides of the combine harvester;       

     a weed seed destructor section comprising:
         a destructor housing arranged to receive from the second discharge location the second material;   a rotor arrangement mounted in the destructor housing for rotation about an axis and including rotor surfaces thereon for engaging the second material and for accelerating the feed material in a direction outwardly from the axis of the rotor;   a stator arrangement mounted at a location along the direction and including a plurality of stator surfaces for engaging the weed seeds in the accelerated second material to cause a plurality of impacts with the weed seeds;   and at least one a discharge mouth for discharge of the second material after the plurality of impacts;       

     said at least one discharge mouth being located so as to direct the second material underneath the bottom wall onto the spreading device. 
     Preferably said rotor arrangement comprises two rotors each having an upstanding axis of rotation with the two rotors arranged side by side across the combine harvester and wherein said at least one discharge mouth comprises two discharge mouths at spaced positions across combine harvester and each arranged to direct the second material underneath the chopper housing onto the spreading device. 
     Preferably the spreading device comprises a tailboard with a plurality of fins and the discharge mouth is oriented to direct the second material onto the fins. 
     Preferably the weed seed destructor section is mounted with an intake in front of the chopper housing and with the rotor and stator underneath the chopper housing. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds for use in a combine harvester where the combine harvester comprises a separation system for separating from harvested crop at a first discharge location a first material comprising straw and at a second discharge location a second material comprising chaff and said weed seeds, the apparatus comprising: 
     a straw chopper section comprising:
         a chopper housing arranged to receive from the first discharge location the first material containing straw;   a chopper rotor mounted in the chopper housing having a plurality of chopping blades for chopping the straw for discharge from the first housing component;   and a spreading device for receiving the straw discharged from the chopper housing and spreading the discharged straw to rear and sides of the combine harvester;       

     a weed seed destructor section comprising:
         a destructor housing arranged to receive from the second discharge location the second material;   a rotor arrangement mounted in the destructor housing for rotation about an axis and including rotor surfaces thereon for engaging the second material and for accelerating the feed material in a direction outwardly from the axis of the rotor;   a stator arrangement mounted at a location along the direction and including a plurality of stator surfaces for engaging the weed seeds in the accelerated second material to cause a plurality of impacts with the weed seeds;   and at least one a discharge mouth for discharge of the second material after the plurality of impacts;       

     and a guide wall component movable between a first position and a second position where: 
     in the first position the chaff and said weed seeds from the second discharge location are directed into the weed seed destructor, while the straw from the first discharge location enters the chopper housing; and 
     in the second position the chaff and said weed seeds from the second discharge location are directed into the chopper housing with the straw. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds for use in a combine harvester where the combine harvester comprises a separation system for separating from harvested crop at a first discharge location a first material comprising straw and at a second discharge location a second material comprising chaff and said weed seeds, the apparatus comprising: 
     a straw chopper section comprising:
         a chopper housing arranged to receive from the first discharge location the first material containing straw;   a chopper rotor mounted in the chopper housing having a plurality of chopping blades for chopping the straw for discharge from the first housing component;   and a spreading device for receiving the straw discharged from the chopper housing and spreading the discharged straw to rear and sides of the combine harvester;       

     a weed seed destructor section comprising:
         a destructor housing arranged to receive from the second discharge location the second material;   a rotor arrangement mounted in the destructor housing for rotation about an axis and including rotor surfaces thereon for engaging the second material and for accelerating the feed material in a direction outwardly from the axis of the rotor;   a stator arrangement mounted at a location along the direction and including a plurality of stator surfaces for engaging the weed seeds in the accelerated second material to cause a plurality of impacts with the weed seeds;       

     and a guide wall component movable between a first position and a second position where: 
     in the first position the chaff and said weed seeds from the second discharge location are directed into the weed seed destructor, while the straw enters the spreading device; and 
     in the second position the chaff and said weed seeds from the second discharge location are directed into the straw spreading device. 
     This arrangement can be used in conjunction with a conventional arrangement in which the chopper section is mounted internally within the combine housing instead of at the rear. Therefore at the rear is provided a rotary type spreader including typically two horizontal disks similar to the conventional chaff spreading system. Thus in this arrangement the chaff and weed seeds form the weed seed destruction section are directed by a guide onto the rotary straw spreader system for common spreading of all material. Again the combined spreading action and the additional air flow can enhance the spreading action to meet the objective of spreading at header width. 
     Preferably the weed seed destructor section is mounted with an intake in front of the chopper housing and with the rotor and stator underneath the chopper housing. 
     Preferably the guide wall component comprises a front wall portion of the chopper housing which is pivotal about an axis across a front of the chopper housing and parallel to the axis of the chopper rotor. 
     Preferably the guide wall component includes a front position which extends from the chopper housing upward and forwardly so as to butt against or adjacent guide wall surfaces for the chaff and for the straw respectively. 
     Preferably there is provided a quick disconnection for halting drive to the rotor of the weed seed destructor when the wall portion is in in the second position. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds for use in a combine harvester where the combine harvester comprises a separation system for separating from harvested crop at a first discharge location a first material comprising straw and at a second discharge location a second material comprising chaff and said weed seeds, the apparatus comprising: 
     a straw chopper section comprising:
         a chopper housing arranged to receive from the first discharge location the first material containing straw;   a chopper rotor mounted in the chopper housing having a plurality of chopping blades for chopping the straw for discharge from the first housing component;   and a spreading device for receiving the straw discharged from the chopper housing and spreading the discharged straw to rear and sides of the combine harvester;       

     a weed seed destructor section comprising:
         a destructor housing arranged to receive from the second discharge location the second material;   a rotor arrangement mounted in the destructor housing for rotation about an axis and including rotor surfaces thereon for engaging the second material and for accelerating the feed material in a direction outwardly from the axis of the rotor;   a stator arrangement mounted at a location along the direction and including a plurality of stator surfaces for engaging the weed seeds in the accelerated second material to cause a plurality of impacts with the weed seeds;   and at least one a discharge mouth for discharge of the second material after the plurality of impacts;       

     at least the weed seed destructor being movable rearwardly of the combine harvester to allow access to a position between the weed seed destructor and the components of the combine harvester at the second discharge location. 
     Preferably the weed seed destructor section is slidable on a guide in a rearward direction. 
     Preferably both the straw chopper section and the weed seed destructor section are movable rearwardly of the combine harvester. 
     Preferably the weed seed destructor section is mounted with an intake in front of the chopper housing and with the rotor and stator underneath the chopper housing. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving from the location a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     a stator arranged at a location along the direction and including one or more stator surfaces for engaging the weed seeds in the accelerated feed material; 
     said stator and said one or more stator surfaces of the stator being arranged such that the weed seeds impact on said one or more stator surfaces and do not pass through the stator along said direction but instead are rebounded therefrom back toward the rotor; 
     the rotor and stator being arranged such that the weed seeds rebound back and forth between the rotor and the stator to provide a plurality of impacts on the accelerated feed material to destroy at least some of the weed seeds; 
     wherein the housing includes a discharge opening for discharge of the feed material after the plurality of impacts, where the discharge opening is at a location different from the stator so that said weed seeds discharged from the rotor through said discharge opening do not pass through the stator. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds comprising: 
     a housing arranged to be mounted at a location on a combine harvester for receiving a feed material containing separated chaff and weed seeds separated by the combine harvester from harvested crop; 
     a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor; 
     at least one stator arranged at a location along the direction and comprising a stator support member and a plurality of stator portions mounted on the support member for engaging the weed seeds in the accelerated feed material; 
     wherein at least one stator includes a frame with replaceable inserts. 
     Preferably inserts of different geometry can be utilized in the assembly 
     Preferably the inserts are a different hardness as compared with the frame 
     Preferably the inserts contain a different material than the stator frame. 
     Preferably therefore the discharge opening for discharge of the feed material after the plurality of impacts the discarded seeds discharge from the rotor and do not pass through the stator but instead are rebounded away from the stator to discharge at a different location. In this way, any foreign bodies are not trapped in the stator to cause damage but instead can escape to the discharge. 
     In the preferred arrangement described in detail hereinafter, the rotor rotates around an axis so as to direct the discarded seeds centrifugally outwardly, and the stator surrounds the axis so as to rebound the discarded seeds back toward the axis and the discharge opening is arranged such that the discarded seeds discharge axially from within the stator. 
     In one arrangement the rotor is mounted directly under the first discharge location of the combine harvester with the rotor axis generally upright so that the feed material fold directly into the top of the housing on to the rotor along the axial direction of the rotor. 
     As an alternate embodiment the apparatus comprises a horizontally rotating tube, with auger fighting in the middle, moving the feed material or chaff to an impact zone at each end of the horizontal rotor. The discharge zone is then at the end and is arranged to expel into the straw chopper of the combine harvester. 
     Preferably as a feature of independent importance the feed material enters the housing axially of the rotor at one end and discharges axially from the opposite end of the rotor. 
     Preferably as a feature of independent importance there is provided a fan component for driving the discarded seeds from the opposite end radially outwardly. 
     Preferably as a feature of independent importance the stator includes a plurality of stator surfaces spaced angularly around the axis. 
     Preferably as a feature of independent importance the stator surfaces are arranged at an angle to a tangent of an imaginary cylindrical surface surrounding the axis. 
     Preferably as a feature of independent importance the angle of the stator surfaces to the tangent is adjustable. 
     Preferably as a feature of independent importance the stator surfaces and/or the rotor surfaces are arranged to pivot so as to increase the spacing therebetween to allow the passage of foreign objects between the rotor and stator. 
     Preferably as a feature of independent importance the stator surfaces are readily removable for replacement when damaged or worn. 
     Preferably as a feature of independent importance the stator surfaces include one or more fins extending generally around the axis. 
     Preferably as a feature of independent importance the housing when viewed in plan longitudinal of the axis of the rotor is of polygonal shape to define a plurality of apexes at angularly spaced positions around the axis and the stator surface in plan view includes a plurality of pairs of stator surfaces which form a V shape converging to a respective one of the apexes. 
     Preferably as a feature of independent importance the rotational speed of the rotor is adjustable to change the number of impacts a seed encounters during its passage. 
     Preferably as a feature of independent importance the velocity of air along the rotor is adjustable to change the number of impacts a seed encounters during its passage. 
     Preferably as a feature of independent importance the rotor and the stator are arranged so that the impacts act to move the discarded seeds along the rotor so as to change the position along the rotor at which the impacts of the discarded seeds occurs. 
     Preferably as a feature of independent importance there is provided two housings each including a rotor and stator arranged side by side across the width of the discharge location. 
     Preferably as a feature of independent importance each of the housings is rotatable about the axis of the respective rotor to change an angle of the discharge around the axis. 
     Also disclosed herein there is provided an apparatus for destroying weed seeds for use in a combine harvester where the combine harvester comprises a separation system for separating from harvested crop at a first discharge location feed material including chaff and said weed seeds and at a second discharge location straw, the apparatus comprising: 
     a straw chopper section comprising:
         a chopper housing for mounting at the second location on the combine harvester for receiving from the first discharge location a feed material containing separated straw separated by the combine harvester from harvested crop;   a chopper rotor mounted in the housing for chopping the straw for discharge from the housing;   and a spreading device onto which the discharged straw is directed;       

     and a weed seed destruction section comprising:
         a housing arranged to be mounted at the first location for receiving from the first discharge location the feed material containing separated chaff and said weed seeds;   a rotor mounted in the housing for rotation about an axis and including rotor surfaces thereon for engaging the feed material and for accelerating the feed material in a direction outwardly from the axis of the rotor;   a stator arranged at a location along the direction and including one or more stator surfaces for engaging the weed seeds in the accelerated feed material to cause impacts with the weed seeds;   wherein the housing includes a discharge opening for discharge of the feed material after the plurality of impacts;       

     wherein the straw chopper section and the weed seed destruction section comprise a common unit. 
     Preferably the common unit includes is a common drive from the combine harvester to the common unit. 
     That is preferably the weed seed destruction section is driven from the straw chopper section. 
     Optionally the weed seed destruction section is driven from an intermediate chopper drive shaft or jackshaft in parallel with the drive to the chopper. That is a main drive belt from the chopper drive output pulley of the combine harvester communicates drive to a lay shaft or jack shaft and then two belts communicates in parallel to the horizontal transverse shaft of the chopper rotor and the horizontal transverse drive shaft underneath the two rotors of the weed seed destruction section 
     In the common unit preferably the weed seed destruction section is arranged such that material from the discharge opening can be fed into the straw chopper section. 
     In this arrangement there are preferably provided two housings each including a rotor and stator arranged side by side across the width of the second discharge location. 
     In this arrangement preferably each of the housings is rotatable about the axis of the respective rotor to change an angle of the discharge around the axis such that the discharge opening can be directed to the side of the combine away from the straw chopper, towards the guide fins of the tailboard of the chopper, or into the housing of the straw chopper. 
     In addition to the above defined features, the seed destruction section can include any of the features previously defined. 
     The arrangement as described hereinafter may provide one or more of the following features and advantages: 
     To provide a seed destroyer in which the residue does not pass through rotating or stationary rings of objects so that there is less potential for damage on passage of a solid object. 
     To provide a seed destroyer in which the impacting members of the destructor can be hard surface coated and easily removable for annual replacement and preparation for the next harvest. 
     To provide a seed destroyer in which the number of hits a seed impacts can be adjusted or tuned for optimum destruction. 
     To provide a seed destroyer which can allow passage of debris such as rocks and other hard objects without damage or destruction, and has replaceable parts should the object cause damage. 
     To provide an integrally mounted seed destroyer in which the trajectory of the discharge can be changed from the side of the combine, to the back of the combine tailboard, or into the chopper so that the residue can be spread with the straw. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: 
         FIG.  1    is an isometric view of an apparatus for destruction of weed seeds according to the present invention which is arranged in a first embodiment where the weed seed destruction section is mounted at a position on a combine harvester at the rear of the sieve so as to discharge the chaff and destroyed seeds away from the straw chopper to both sides of the combine harvester. 
         FIG.  2    is an isometric view from the front and one side of the combined apparatus including the straw chopper section and the weed seed destruction section of  FIG.  1   . 
         FIG.  2 A  is an isometric view from the rear and the other side of the combined apparatus including the straw chopper section and the weed seed destruction section of  FIG.  1   . 
         FIG.  3    is an isometric view of the weed seed destruction section of  FIG.  1    separate from the combine harvester with the discharge housing arranged for discharge to the sides. 
         FIG.  4    is a top plan view of the weed seed destruction section of  FIG.  3    separate from the combine harvester with the discharge housing arranged for discharge to the rear. 
         FIG.  5    is an isometric view of the weed seed destruction section of  FIG.  3    with a part of the housing removed. 
         FIG.  6    is an isometric view of the weed seed destruction section according to the present invention which is arranged to feed the discharged material into the chopper rotor of the straw chopper section at the center thereof. 
         FIG.  7    is an isometric view of the apparatus of  FIG.  6    adjusted to feed the discharged material into the straw chopper section at the sides so as to bypass the rotor and feed directly onto the tailboard. 
         FIG.  8    is a side elevational view of the apparatus of  FIG.  2    showing the drive system to the combined apparatus including the straw chopper section and the seed destructor section. 
         FIG.  9    is a plan view of an alternative arrangement of the weed seed destruction section where the rotors are arranged to rotate about a horizontal axis and thus rotate in a vertical plane to discharge rearwardly. 
         FIG.  10    is an isometric view of another embodiment of an apparatus for destruction of weed seeds according to the present invention where  FIG.  10    shows the cross-section of the structure of the rotor assembly and the left side only show the rotor, right side shows the rotor and stator. 
         FIG.  11    is an isometric view the embodiment of  FIG.  10    where  FIG.  11    shows the structure of one rotor assembly with one cover removed. 
         FIG.  12    is a cross-sectional view along the lines  12 - 12  of  FIG.  10   . 
         FIG.  13    is an isometric view of one stator frame of the embodiment of  FIG.  10    including the replaceable stator components. 
         FIG.  14    is an isometric view of the stator frame of  FIG.  13    with the replaceable stator components inserted and showing a number of alternative arrangements of the components. 
         FIG.  15    is an isometric view from below of one rotor of the embodiment of  FIG.  16     
         FIG.  16    is a cross sectional view on an enlarged scale of one part of the apparatus of  FIG.  10   . 
         FIG.  17    is an isometric view from one side and the rear of the combined apparatus including the straw chopper section and the weed seed destruction section of the above Figures. 
         FIG.  18    is an isometric view from one side and the front of the combined apparatus including the straw chopper section and the weed seed destruction section of  FIG.  17   . 
         FIG.  19    is a cross-sectional view of the apparatus of  FIGS.  17  and  18    mounted on a combine harvester and showing the apparatus in a rearwardly displaced position providing access to the sieve of the combine harvester 
         FIG.  20    is a cross-sectional view of the apparatus of  FIGS.  17  and  18    mounted on a combine harvester and showing the apparatus in a first operating position in which the straw passes through the chopper housing and the chaff and weed seeds pass through the seed destructor section. 
         FIG.  21    is a cross-sectional view of the apparatus of  FIGS.  17  and  18    mounted on a combine harvester and showing the apparatus in a second operating position in which both the chaff and weed seeds and the straw pass through the chopper housing. 
     
    
    
     In the drawings like characters of reference indicate corresponding parts in the different figures. 
     DETAILED DESCRIPTION 
     The apparatus herein is shown in  FIG.  1    mounted on a combine harvester  1  carried on ground wheels  3  and including harvesting components of a conventional nature the rearmost one of which is the sieve  2  which discharges chaff and discarded seeds including weed seeds to the rear edge  4  of the sieve. 
     The combine harvester includes a chopper and discharge arrangement  9  shown in  FIGS.  1  and  6    is basically as shown in U.S. Pat. No. 6,840,854 issued Jan. 11, 2005 of Redekop, the disclosure of which is incorporated herein by reference. The chopper thus comprises a housing  10  defined by a top wall  11 , a bottom wall  12  and two end walls  13 . The end walls  13  include attachment means  13 A for attachment of the housing to the outlet of a combine harvester for discharge of straw and optionally chaff from the combine harvester into an inlet opening  15  of the housing  10 . The bottom wall  12  defines a semi-cylindrical portion extending from the inlet  15  to an outlet  16  through which chopped straw and air is discharged at relatively high velocity for spreading across the field or for transportation into a container. 
     Within the housing is mounted a hub  17  which is carried on suitable bearings  31  for rotation about a hub axis  18  at a center of the housing so that blade members  19  carried by the hub sweep around within the housing to entrap straw fed through the inlet  15  and to carry the straw and air past stationary blades  20  for chopping and for discharge through the outlet  16 . The stationary blades  20  are mounted on the housing at a position approximately midway between the inlet  15  and the outlet  16  so that the blade members  19  sweep between the stationary blades in a cutting action. 
     The hub  17  carries a plurality of lugs  21  at angularly and axially spaced positions therealong with each lug mounting a pair of blades  19  for pivotal movement of the blade members  19  about a pin  22  parallel to the axis  18 . Each of the lugs  21  carries a pair of the blades  19 . Each lug  21  is aligned with a respective one of the stationary blades  20  so that each stationary blade has associated with it a respective one of the lugs and thus has associated with it the pair of blades carried by that lug. 
     In this arrangement of the chopper, there is provided three axially spaced sections of the chopper assembly including a first fan section  30  at one end of the hub  17  and the second fan section at the other end of the hub  17 . In-between the two narrow fan sections  30  is defined a center section  30 A which provides the whole of the cutting action. 
     Within the center section  30 A all of the blades  19  are formed with a cutting edge lying in a radial plane of the axis. The blades are preferably of the conventional flat blade type with a leading and trailing chamfered edge. Thus each of the two cutting blades  19  in the center section can pass closely on either side of a respective one of the stationary blades  20 . Thus the stationary blades can be spaced by a distance which is just sufficient to allow the passage there between of the preferably flat cutting blade. In the preferred arrangement, the spacing between the stationary blades is thus small in that the stationary blades are not sufficiently spaced to allow the passage there between of a fan type blade. 
     In the fan sections  30 , there is provided a ring  33  which is mounted on the hub  17  at a respective end of the hub. The ring thus surrounds the cylindrical wall of the hub and stands outwardly therefrom just beyond the end of the center section defined by the stationary blades and the blades  19  carried on the hub. 
     The rings  33  each carry a plurality of fan blades  34  at spaced positions around the ring. The fan blades  34  are arranged thus so that each follow directly behind the next at the same axial location. 
     Each of the fan blades  34  is bent with a fan blade portion so that each of the fan blades is of the shape shown in FIG. 3 of U.S. Pat. No. 5,482,508 of Redekop, the disclosure of which is incorporated herein by reference. However the fan blades  34  do not necessarily have a sharpened leading edge since there is intended to be no cutting action in the fan section. Thus the fan blades are spaced from the end most stationary blade  19  so that in effect no cutting action occurs in this section. 
     The bent fan blade portion stands outwardly to one side of the flat plate portion of the fan blade  34 . The fan blade portion which is bent at right angles to the main body of the fan blade is maximised in dimension so that it may be rectangular. This large blade area together with the presence of the six blades provides a large fan blade area which generates a significant air flow. 
     The fan blade portion is inclined forwardly and outwardly so that at a regularly outer position toward the outer end of each fan blade the fan blade portion is angularly advanced relative to its position closer to the axis of the hub. This incline outwardly and forwardly significantly increases the air flow effect driving the air in the greater volume and at higher speed radially from the fan section and outwardly of the exit  16 . 
     Preferably the fan section comprises only a single row of the six fan blades but in some cases an additional row or rows may be provided although this is not preferred. The fan blades are arranged immediately adjacent the end walls  13  so that they take up minimum space at the end of the chopper assembly. It will be appreciated that the intention is to provide maximum air flow in the fan sections while taking up minimum dimensions so that the maximised chopping effect to provide shortest material is achieved within the center section using the flat blades. 
     The above arrangement of straw chopper section is one example only of arrangements which can be used herein. 
     The chopper and spreading assembly  9  is arranged to be mounted at a rear straw discharge  101  of the combine harvester  1  and includes the housing  10 , the rotor  17  mounted in the housing  10  for rotation around a generally horizontal axis and carrying the plurality of chopper blades  19  for chopping the discharge material. 
     At the exit  16  is provided the material spreading assembly which can be the form of a tailboard  16 A with guide fins  16 B for receiving the chopped material and spreading the material to the rear and sides of the combine harvester. 
     An apparatus  35  for destroying seeds comprises a body  36  carried on a frame  37  mounted at a suitable location on the combine harvester by mounting arrangements of a conventional arrangement. The body provides two side by side housings  38 ,  39  each located adjacent a respected half of the discharge location the feed material containing separated chaff and discarded seeds separated by the combine harvester from harvested crop. In the embodiment shown in  FIG.  1   , the housings are located at the rear edge  4  of the sieve  2 . 
     Each of the housings, as best shown in  FIGS.  3 ,  4  and  5    includes an upper impact section  40  and a lower fan section  41 . The upper section  40  includes a housing  42  which is polygonal (in this example octagonal) in plan view with apexes  43 A,  43 B,  43 C etc. The housing  42  incudes a top wall  44  connected to the polygonal side wall and defining a circular opening  45  arranged to be mounted at the discharge location of a combine harvester for receiving from the sieve the chaff and discarded seeds including the weed seeds. 
     A rotor  46  is mounted in the housing for rotation about an upstanding axis  47  at right angles to a bottom base of the housing axis. The rotor includes a cylindrical hub  46 A carrying upper and lower sets of blades  46 B and  46 C. The sets are spaced axially. The individual blades of the set are spaced angularly. The sets are carried above and below respectively a series of angularly spaced lugs  46 D on pins  46 E so as to act as blades. 
     Each blade includes as best shown in  FIG.  5    a base plate  46 F lying in a radial plane and a blade portion  46 G turned out of the radial plane so as to act as a fan blade to drive entrained air and the material centrifugally outwardly from the axis of the rotor. 
     Thus the rotor includes components thereon defined by the two sets of blades for engaging the feed material and for accelerating the feed material in a centrifugal direction away from the rotor. 
     In the housing around the rotor is provided a stator  48  defined by the inside surface of the polygonal housing  40  and arranged at a location centrifugally outside the rotor  46  so that the material and discarded seeds thrown outwardly impact on the stator. The stator includes a series of surface elements  48 A for engaging the discarded seeds in the accelerated material and arranged such that the discarded seeds impact thereon and rebound therefrom back toward the rotor. 
     Thus the rotor  46  and stator  48  are arranged such that the discarded seeds rebound back and forth between the rotor  46  and the stator  48  to provide a plurality of impacts on the feed material to destroy the seeds. 
     The housing includes a discharge opening defined by a circular inner edge  50 A of a plate  50  lying in a radial plane of the housing between the impact section  40  and the fan section  41 . Thus the bottom of the impact section is defined by the bottom plate  50  so that air and the entrained material is directed downwardly into the fan section for discharge of the feed material after the plurality of impacts. As the air and entrained material passes downwardly, the discarded seeds discharge from the rotor and do not pass or escape outwardly through the stator  48 . That is the stator wholly or substantially wholly surrounds the rotor section to prevent the seeds from escaping radially. That is all of the seeds are rebounded back inwardly to the rotor and move downwardly while rebounding back and forth until they pass out of the impact section at the bottom through the hole  50 A in the plate  50  into the fan section  41 . 
     Thus the rotor  46  rotates around the axis  47  so as to direct the discarded seeds centrifugally outwardly. The stator  48  surrounds the axis  47  so as to rebound the discarded seeds back toward the axis and the discharge opening is arranged such that the discarded seeds discharge axially from within the stator. In this way, the feed material containing the discarded seeds enters the housing axially of the rotor at the top end and discharges axially from the bottom end of the rotor into the fan section, where the material is accelerated radially outwardly into a channel defined by a peripheral wall  41 A which spirals gradually outwardly from a leading edge to a trailing edge  41 B so as to define an outlet location  41 C. 
     Thus the fan section  41  shown in plan in  FIG.  4    at the top includes a series of blades  41 F carried on the rotor  46 A underneath the plate  50  so that the fan components act for driving the discarded seeds from the opposite or bottom end of the rotor  46  radially outwardly to the discharge opening  41 C at the trailing edge  41 B. 
     As best shown in  FIG.  5   , each of the stator surfaces  48 A comprises a generally V-shaped body with two walls  48 B and  48 C converging to an apex  48 D which is located at one of the apexes of the polygonally shaped housing. In  FIG.  5    is shown one of the stator surfaces  48 A and it will be noted that the wall  48 C against which the seeds are primarily directed as the rotor  46  turns clockwise is arranged at an angle to a tangent T of an imaginary cylindrical surface surrounding the axis. Thus the surface  48 C is inclined forwardly and inwardly so that the seeds moving with the rotor and outwardly of the rotor impact against the surface  48 C and are rebounded inwardly. The stator surface portion  48 A is mounted at the apex  48 D by a hinge pin  48 H which allows the angle of the stator surface  48 C to the tangent T to be adjustable to change the level of aggression in the rebound action. 
     Also the hinged mounting of the stator surface portion  48 A allows the stator surfaces to pivot to allow the passage of foreign objects between the rotor  46  at the outer tip of the blades  46 B,  46 C and stator as defined by the surface portions  48 A. Also the stator surface portions are readily removable for replacement by pulling the support pin  48 H when damaged or worn. 
     Also the stator surface portions  48 A include one or more fins  48 G lying in a plane at right angles to the walls  48 B,  48 C and thus extending in a radial plane around the rotor. The stator has an octagonal shape and there are four of the stator surface portions  48 A at four of the apexes of the polygon leaving the remainder of the inner surface of the octagon exposed to act as the stator surface. This stator surface surrounds the whole of the rotor and hence prevents outward escape of any material, thus confining the material to move downwardly into the fan section for ejection. 
     The rotor  46  which carries both the blades of the impact section and fan blades  41 F of the discharge fan section  41  as best shown in  FIG.  8   , is driven by a hydraulic drive motor  46 H, the rotational speed of which is adjustable to change the speed of the impact blades and thus the number of impacts a seed encounters during its passage. 
     Also the velocity of air along the rotor through the impact section from the opening at the top plate  44  to the discharge plate  50  is adjustable to change the number of impacts a seed encounters during its passage. 
     The rotor and particularly the stator are shaped and arranged so that the impacts and rebounding action act to move the discarded seeds along the rotor from the feed opening at the top plate  44  to the discharge opening at the plate  50  so as to change the position along the rotor at which the impacts of the discarded seeds occurs. Thus the seeds as they rebound back and forth move through the impact section at a rate depending on the shape and position of the stator surfaces and depending on the rotation rate of the rotor and the air speed through the impact section. 
     In a typical walker style combine there is a large space between chopper  9  and the end of the sieve  2 . In this case the seed destructor  36  is mounted at the end of the sieve  2 . In this position, the discharge openings  41 C of the fan section  41  are located by rotating the housings  38 ,  39  so that the seed destructor discharge is set to the side because the discharges are not close enough to the chopper  9  to allow feeding into the chopper. 
     The seed destructor is made up of two rotating drums or rotors  46  within the housings  38  and  39  rotating in opposite directions. The housings are rotatably mounted on the frame  37  so that the discharge  41 C can be pointed in the direction required. Although this is shown as a fixed mounting it could be easily designed as a movable mounting so the operator could change it quickly as desired. In one arrangement the adjustment can be obtained conveniently by rotation of the housing around the axis of the rotor. 
     The impact section  40  contains in the stator  48  replaceable, adjustable impact plates or surface portions  48 A, in which the residue that is dropped into the seed destructor housing is flung against by the rotors  46  with blades  46 B and  46 C. The residue is deflected back by the stator into the rotating blades for another hit. 
     The fan section  41  at the bottom of the housing acts to accelerate the residue for spreading back onto the field or into the chopper or into the chopper fins as desired. 
     The rotors can be driven by hydraulic motors which power and mount the rotating hubs  46  in which case the motors are mounted to the frame  37 . 
     The impact plates  48 A are rotatably adjustable at the apex  48 D and designed to deflect the residue back into the high speed blades. The guide fins  48 G on the impact plates serve to control the angle that the residue is deflected and therefore the number of times the residue rotates in the housing and thus the number of hits a seed encounters in its passage through the destructor. The impact plates  48 A are replaceable and are hard surface coated for a longer life. 
     At the bottom of the housing assembly below the fan section  41  is provided a bottom plate  60  closing the bottom of the fan section  41  below the plate  50 . In the plate  60  is defined an air inlet schematically indicated at  62  which regulates the flow of exterior air into the fan section through the plate  60 . The opening size of the air inlet  62  can also be varied by an adjustment  62 A. As the adjustment  62 A control the amount of air entering into the fan section, this adjustment increases or reduces the amount of air drawn through the opening  50 A in the plate  50  and thus also serves to change the speed of the residue flowing through the assembly. The air inlet  62  can be regulated so that, as it is closed off, the speed of the residue flow increases, to the point when closed, all air is sucked in from the top of the assembly at the plate  44 , to be discharged with the fan in the discharge zone  41 . When entirely opened the majority of the air is drawn from the bottom plate  60  of the assembly and the speed of the residue flowing through the assembly is reduced allowing for more impacts. 
     A third method to adjust the number of impacts a seed encounters through the assembly is of course with the speed of the rotor  46 . The drive system to the rotor can be controlled by the combine or by a separate driver operated control and the speed of the assembly can be increased or decreased depending on factors such as seed size, residue toughness, or residue size including factors such as corn cob size and moisture content or sunflower head size. 
     In a preferred arrangement, the seed destructor section  36  is integrated into the chopper  9  as a common unit with the chopper  9 . In this arrangement the seed destruction section  36  acts two receive all residue from the sieves. The weed seeds are destroyed in the seed destructor and can be ejected into the chopper for spread with the straw residue on the tailboard  16 A. 
     In this arrangement the combination of all of the residue from both the sieves and the straw exit into the chopper allows the destroyed seeds and chaff residue to mix with the straw residue and be spread in a much wider spread pattern. That is in  FIG.  6   , the discharge openings  41 C from the fan section  41  of the seed destruction section  36  are turned on the frame  37  so that they are directed to the center of the inlet  12  of the chopper  9 . 
     Alternatively the chaff residue and destroyed seeds expelled from the seed destructor at the discharge openings  41 C is expelled at the sides of the chopper at the fan sections  30  so as to bypass the center chopper section of the chopper so as to be directed by the chopper into the fins of the chopper for mixing on the tailboard  16 A and spreading with the straw residue from the chopper. 
     As a third option, the discharge openings  41 C can be positioned to the side to spread to the side of the combine as shown in  FIG.  1   . Thus the seed destruction section  36  is a part of or closely associated with the chopper  9 . However the position of the outlet in the embodiment of  FIG.  20    can be adjusted to the side in the same manner by rotation of the housings on the frame  37 . 
     Thus the destruction section  36  and the chopper  9  form a common unit which can be supplied as a common assembly for attachment to the combine harvester. The common unit may include a common frame. The common unit can include a common drive arrangement by which a single output drive from the combine harvester is directed to the common unit and then directed by the drive mechanism to the chopper rotor and to the seed destruction section. The common unit can be arranged so that in one or more adjustment positions of the seed of destruction section the output from the fan section is directed into the chopper for common distribution into the field. It is also possible in this arrangement that the seed destruction section be adjusted so that the output therefrom is directed into the field bypassing the chopper. 
     In an arrangement where the space between the sieve  2  and the straw outlet is greater than can be accommodated by direct feed from the sieve into the inlet of the seed destruction section, a feed duct or other transfer arrangement can be provided. 
     Thus the combined apparatus comprises the straw chopper  9  as described above together with the apparatus for destroying weed seeds as described above where the discharge opening of the housing is arranged such that the discharge opening can be directed to the side of the combine away from the straw chopper, towards the guide fins of the tailboard of the chopper, or into the housing of the straw chopper. 
     As an alternate embodiment shown in  FIG.  8    the apparatus can be designed as a horizontal tube  70  into which the material is fed from the sieve  2  by a feed duct  2 A. This can be readily located at this position by a combine manufacturer as a horizontal duct in their combine at a position ahead of the rear discharge for chaff. 
     The tube  70  has a transverse shaft  71  driven at one end  72  and carried on end walls of the tube  70  at bearings  73 . The shaft carries auger fighting  74 A,  74 B in the middle moving chaff outwardly to an impact zone  75  at each end of the horizontal rotor. The arrangement thus provides a seed destructor symmetrical to and operating in the same manner as that previously described but arranged in an orientation at 90 degrees to that shown previously and rotating in a vertical plane about a horizontal axis defined by the shaft  71 . Thus the destructor  75  includes a rotor  77  and stator  78  as previously described and a fan section  79  so that the discharge zone  76  is located at the end to expel into a secondary spreading device, or into a straw chopper or into the tail board fins of the straw chopper. 
     As shown in  FIGS.  2 A and  8    housing of the chopper section  9  and the seed destructor section  35  are formed as a common or integral construction coupled together as single or common unit which can be mounted on the combine harvester at the rear of the combine so as to be associated with the rear straw discharge and the rear chaff discharge. 
     The chopper  9  has an input drive pulley  9 A connected to the rotor  17  driven by a belt  9 C or other drive component or pulley assembly  9 B from the combine. In addition the pulley  9 A of the chopper drives an output pulley  9 D which communicates drive to the seed of destruction section  35  through a pulley  9 E driven by a belt  9 F. In the arrangement shown the pulleys  9 A and  9 D are mounted at the same end of the rotor  17  but this is not essential. The drive  9 B to the chopper can be as shown where the output shaft  9 G of the combine drives a belt  9 H connected to a pulley system  9 K to drive the belt  9 C; but of course other drive arrangements can be used such as a shaft from an output gearbox. 
     A shroud or hood  35 A is over the seed destructor section to allow for the chaff to be directed underneath the hood into the seed destructor. A roller  35 B is required at the leading edge of the hood  35 A to eliminate material buildup on the leading edge which could cause possible plugging. The roller rotates in a clockwise direction at 200-500 rpm to roll any long straw over to the chopper section  9  while the chaff and weed seeds flow under the hood the destructor section  35 . 
     While the arrangement shown herein is shown as an externally mounted chopper carried on the combine harvester at the rear straw discharge, some combines include an internal chopper mounted in the housing at a position in advance of the rear discharge. In this arrangement the seed destructor section can be located at the chaff discharge and arranged to direct material into the internal chopper or away from the internal chopper to the ground. In this case the internal chopper does not cooperate directly with a spreading system such as a tail board. 
     Turning now to  FIGS.  10  to  16   , there is shown a modified embodiment of the seed destructor which includes two separate destructor elements side by side each including a housing  80  with base  81  and a spiral outer surface  82  upstanding from the base and extending to an outlet or discharge mouth  96 . The base and outer surface are covered by a top planar cover panel  801  which has an opening  83  Inside a center part of the spiral which defines a central inlet for feeding the material from the sieve containing the chaff and weed seeds onto a rotor  84  mounted on a hub  85 . Around the hub  85  is provided a plurality of pivot pins or bolts  86  each carrying a pair of flail blades  87 . The blades extend from an inner end with a plurality of fingers extending into connection to the pin  86  between a plurality of disks  844  of the hub  85 . An outer end of the blade  85  broadens in the axial direction of the axis of the hub as shown at  842  and terminates in an edge  843  lying in an imaginary cylindrical surface surrounding the axis. The blades can retract inwardly by pivotal movement in the event of impact with a larger object. Thus the blades are pivotally mounted about an axis parallel to the rotor axis so as to act as flails. Also each of the rotor blades includes a sharpened cutting edge  84 C radial to the axis and a fan blade portion  84 F generally axial of the axis so that the blades are of a similar construction to those used in the chopper and described above. 
     Around the rotor is provided a stator formed by two stationary annular coaxial cylinders  89  and  90  with cylinder  89  inside the cylinder  90 . The stator cylinders are carried on the base  81  so as to stand upwardly therefrom or they may be attached to the top cover so that they hang down from an upper annular flange  891  fixed to the cover. Shown in  FIG.  12    a seal  201  is provided to limit the passage of weed seed from the central inlet to the outlet through the clearance between the rotor and stator. The sealing ring  201  forces the weed seeds to contact the stator and rotor thus devitalizing the seed. 
     The base  81  is carried on a beam  811  which mounts the two destructor elements side by side and provides drive through an input shaft  812  and two gear boxes  813 ,  814  to the upstanding shafts  81 X driving the hubs  85 . The cover  801  is rigidly fixed and centered on the beam  811  so as to hold the stator in fixed coaxial relationship with the rotor against movement which could allow interference between the rapidly rotating rotors and the stator cylinders. 
     Each stator cylinder is of the construction shown in  FIG.  14    and includes the top flange  891 , a bottom ring  892  parallel to the flange and a plurality of upstanding connecting rails  893  to form a rigid structure as shown in  FIG.  13   . 
     The stator cylinder has a plurality of stator inserts  894  closing the space between the flange  891  and the bottom ring  892 . Each insert forms a part cylindrical surface which extends around the axis by a limited angle. As shown in  FIG.  13    there are six such inserts each covering an angle of the order of 60 degrees so that the plurality of inserts cooperate to surround the axis. The number of bars in the inserts can be selected to increase or decrease the number of openings and the angular extent of the plates can be selected to determine the angle over which the opening extends. 
     Each stator insert  894  is made up of a number of impact bars. Typically the insert is formed with two cylindrical flanges of a suitable metal which is then laser cut to form holes in an array to mount the impact bars. Different constructions of plate can be provided with different arrays and sizes of impact bars to provide a different grinding or impacting effect on the material in engagement with the plates. The inserts are shaped with an angled edge flange  897  which is shaped to engage against a side edge of a suitably shaped one of the rails  893 . Thus as shown in  FIG.  13   , the ends  897  of the plates  894  engage against sides of the rails  898  and  899  with the opening  895  therebetween. Additional rails  901  between the end rails act as supports engaging the outer surface of the wall of the plate. 
     In  FIG.  14   , three types of stator inserts are shown, of which many more styles could be envisioned, which can be selected for use in the base frame of  FIG.  13   . In one insert the bars are round and shown extending in the vertical direction. In another insert the bars have a sharp square edge to quickly remove seed from the mill. In the third type of insert shown at  902 , the insert is formed by a series of tightly spaced round bars  903  arranged with reduced openings between the bars to keep the seeds in the mill longer and thus create more damaging impacts. In practice the different inserts are used together at different locations in the mill to create the desired devitalization properties. 
     As shown in  FIG.  14    therefore the mill includes at least one stator which includes an external frame with top and bottom rails containing replaceable inserts. This allows inserts of different geometry to be utilized in the assembly as selected depending on the type of seeds and conditions involved in the operation. Thus the different types of inserts using the different shape and spacing of the bars can be used to obtain the different effects. The system may use inserts only of one type or of different types as required. In order to provide the best wear characteristics, the inserts can be of a different hardness as compared with the frame allowing the frame to be constructed in a different manner than the inserts which require typically a greater hardness. The smaller components of the inserts allow a more effective hardening process to be used. In particular, the inserts can contain or comprise a different material than the stator frame. 
     In operation, the rotor flails  87  acts to accelerate, impact and direct the material across the inside surface of the inner stator insert  89  to impact, shear and force some of the material through the bars. The outer edge  843  of the flail blade thus acts to direct the material cross the inside surface of the selected stator insert with the edge  843  having a height substantially matching the height of the insert. 
     That material which does not escape through the bars  896  is carried around the inner surface of the insert  894  to the next one of a plurality of discharge slots or holes  895  around the plate  894 . The material sliding on the inner surface thus can escape through the inner stator  89  to the next outer annular stator  90 . Between the two stators  89 ,  90  is a ring of posts  92  which are attached to a base plate of the rotor so as to rotate with the center hub and flail blades. These posts act to impact, accelerate and shear the material round the inside surface of the outer stator  90 . 
     The stator  90  has the same structure as the stator  89  but of increased diameter. Again there is a plurality of separate stator inserts  906  at angularly spaced positions. The outer stator therefore operates in the same manner under the rotation impetus on the material from the posts  92  to impact and shear the material and then to allow any remaining material remaining on the inner surface of the outer stator to escape outwardly through the openings  907  in the outer stator. The material escaping the slots is accelerated angularly by a final series of posts  94  attached to the rotating base of the rotor so that the material is flung outwardly and angularly against the outer stator surface  82 . 
     Each stator which is in the form of a ring or cylinder supported from the top cover and located between the components of the rotor is thus formed from the fixed base frame shown in  FIG.  13    with a plurality of locations each for mounting a respective one of the stator plate components with an outlet opening between each component and the next. As shown in  FIG.  14   , different forms of the stator inserts can then be selected for use with the frame of  FIG.  13    and installed and replaced as required. 
     The use of separate stator inserts provides replaceable stator components which have a number of advantages which include: 
     -a- simple service, it is possible to replace and discard small parts of the stator rather than the entire stator ring. 
     -b- customer cost, the arrangement provides lower cost service parts, longer lasting parts with the possibility that the smaller parts of the components alone can be made harder. 
     -c- manufacturing advantage, the components individually are lower cost, higher volume of a smaller part allowing economy of scale to provide cheaper manufacturing. 
     -d- material, the manufacture of a smaller part allows the use of a higher value material for that part while the frame itself can be manufactured from other materials. This allows less material to be used, allows for harder or heat treatable material to be used for the wear surfaces of the replaceable stator components while softer, more ductile or weldable material can be used in the frame. In particular the stator components or plates form small parts which are suitable for hard surfacing or carbide coating processes to provide increased hardness and wear resistance. 
     -e- Stator selection; this allows for different stator wear surface profiles, that is different shapes and arrangements of impact bars, to be selectable to best match to typical weed seed targets in each farming region. That is different regions in the world have different weed problems, so that the system of the present invention allows use of a common support frame and different wear inserts to best target the efficacy of the desired weed seed in that region. 
     -f- Stator Style; the system can provide different styles of stator inserts to cover different manufacturers particular design of the stator. That is the stator component can carry a series of different impact elements  903  arranged on the component around the angular extent of the component with tighter impact elements separated by inserts designed to discharge seeds to the next stage. 
     The stator impact surfaces  903  can be movable in an adjustment movement about an axis parallel to the rotor axis so that the surface pivots relative to a tangent to the axis of the rotor so as to change the number of impacts caused to each weed seed. The replaceable stator surfaces may hard surface coated with a suitable material such as carbide which reduces impact damage. One or both stators  89  and  90  defined by the annular frame and the supported stator components can be adjusted by rotation around the axis of the rotor so as to move the position of the slots  895 . This acts to change the distance that the material must traverse before it reaches a larger opening between impact bars. 
     As shown in  FIG.  12   , the angular position of the stators  89  and  91  is adjustable around the axis X of the hub to move the openings  895  angularly. If the wider openings  895  of the inner stator  89  are located at an angular portions so that they are aligned with the widest openings  895  of the outer stator then any material exiting the openings of the inner stator will typically escape from the second stator by direct radial movement through both openings simultaneously thus minimizing any processing by the outer stator. Movement of one or both of the stators so that the inserts with the widest openings are not aligned will increase the effective processing by the second outer stator. It will be appreciated that this processing can be adjusted from a position of minimum processing where the widest opening are aligned to a position of maximum processing where each opening in the inner stator discharges onto the outer stator at a distance which is at the beginning of the adjacent stator component so that the material must traverse the whole surface of the narrowest opening insert before reaching an insert with a wide opening  895  in the outer stator. Also as shown in  FIG.  11    are actuators  911   912  operated by a control  913  where the control is in the cab for on-the-go control of the position of the stators. 
     It will be appreciated that the weed destructor herein uses a significant amount of power to drive when empty and an increased amount when filled with the crop materials. This power can be minimized by bypassing the device as described herein and by disconnecting the drive thereto when no treatment of the crop materials is required. The power can be reduced as above by moving the stators to the most effective position with minimum crop treatment. 
     Thus the system herein provides adjustability of stator positions on the go, the advantages of which include: 
     -a- Setting the stator contact surface to produce the best efficacy rate to match weed problems in field while reducing power requirements. 
     -b- Reducing power by reducing stator contact time of the crop material. This is a significant advantage includes which allows increased combine harvest capacity as current destructor systems are reducing a farmer&#39;s threshing capacity by up to 30% as well as reduced fuel consumption. 
     -c- Manual Adjustment on the go by In Cab control of an actuator allows the operator to change as they enter visible weed problem areas in the field. The actuator drives relative position of the stator rings to change the number of impact surfaces a seed encounters as it passes through the mill. 
     -d- Automatic Adjustment on the go allows an operator to develop a GPS map of a weed problem by aerial surveillance or when mid-season spraying. This information can be used to adjust the stator positions for maximum seed efficacy using maximum power in that area and reduce contact surface after the combine passes through the weed area. 
     As shown in  FIG.  15    the rotor also includes an additional swinging blade element outside of the outer stator element. This is used to overcome problems encountered in green re-growth areas of fields. It is typical for combine operators to desire to “mow down” green areas of the field as they often represent weed infested areas. This usually results in the heavy green material falling from the combine beater down onto the sieves, rather than being thrown to the chopper. Thus this green material is carried into the inlets  83  of the destructor units. In an arrangement where the stator surface acts as the last obstacle before the residue is ejected from the housing, this wet sticky material piles up and blocks the exit  96  of the housing. In this arrangement, mechanical ejection by a blade is provided to ensure the mill remains clear in conditions with heavy, wet or damp materials. As shown the blade  100  comprises a flat blade with a cutting edge  101  and an inclined downturned fan blade portion  102  to create more airflow thus discharging any buildup with contact and increased airflow. 
     As set forth above the rotor surfaces and optionally the stator surfaces are arranged to pivot to a position to increase a spacing between the stator and rotor surfaces to allow the passage of foreign objects between the rotor and stator surfaces. 
     The rotational speed of the rotor is adjustable to change the number of impacts a seed encounters during its passage. 
     In at least one stage, therefore, the weed seeds do not pass through the stator but are rebounded between the rotor and the stator. The rotor also propels the weed seed from the housing without needing to pass through an outside stator surface so that a higher exit velocity is obtained. 
     Turning now to  FIGS.  17  to  21    there is shown a further embodiment of apparatus for destroying weed seeds which is similar to that shown in  FIG.  8    in that it includes a straw chopper section  9  and a weed seed destructor section  35 . The section  35  is of the construction shown in  FIG.  10    so that it has an inlet  351  in the center of the housing  80  which is fed by a par of inlet chutes  352  taking the feed from across the sieve  354  which drops into a channel  353 . Thus the intake of the destructor  35  is located in front (with respect to the direction of travel) of the chopper housing and with the rotor and stator underneath the chopper housing. 
     As best shown in  FIG.  20   , the destructor  35  is mounted on the housing of the chopper at a position lower than in  FIG.  8    so that the top wall of the destructor  35  is underneath the bottom wall  355  of the chopper housing. Thus the discharge mouths  96  release the chaff and weed seeds from a position below the chopper that is underneath the bottom wall of the chopper housing so as to direct the second material along the direction F underneath the bottom wall  355  directly onto the tailboard  16 A forming the spreading device. Thus the tailboard  16 A is inclined downwardly and the chaff is fed onto the tailboard to join with the straw and airflow from the chopper so that both materials are spread in a common action by the fins  16 B. This acts to provide an improved spreading action on the chaff which tends to be very light and fluffy due to its passage through the destructor. Thus the added momentum from the heavier and more dense straw is communicated to the fluffier chaff to provide a full spreading action which can match the cutting width of the header. 
     As shown by comparing  FIGS.  20  and  21    the guide channel  353  includes a guide wall component  356  movable between a first position shown in  FIG.  14    and a second position shown in  FIG.  21   . 
     In  FIG.  20    the chaff and weed seeds from the sieve are directed into the weed seed destructor, while the straw from the first discharge location enters the chopper housing. This is achieved by moving the component  356  from a position in  FIG.  20    which is raised so that the chaff passes underneath the component. Thus the component includes a portion  360  defining a front wall of the chopper and an upper tip portion  357  which contacts a guide surface  361  of the straw channel from the combine. In  FIG.  21    the component  356  Is moved so that the tip portion  357  engages a guide surface  359  of the chaff transfer channel from the sieve  354 . Thus in the second position shown in  FIG.  21    the component  356  shuts off the flow to the destructor  35  and instead directs the chaff and weed seeds from the second discharge location into the chopper housing with the straw. 
     The guide wall component  356  comprises the front wall portion  360  of the chopper housing which is pivotal about an axis  364  across a front of the chopper housing and parallel to the axis of the chopper rotor. 
     When the system is arranged to bypass the destructor as shown in  FIG.  21   , a clutch  362  is operated to halt drive to the rotors of the weed seed destructor  35  from the input drive shaft  363 . 
     Adjustment of the passage of chaff into the mill and powering of the mill on the go provides advantages: 
     -a- Based on either IN CAB operator control or GPS control, an actuator drives the door  356  at the front of the chopper to bypass the mill and flow all residue into the chopper or alternately direct chaff into the mill and only straw into the chopper, thus saving power, time, combine capacity when not needed. 
     -b- At the same time the actuator operates the clutch  362  to stop the mill from turning when not needed, thus eliminating the empty mill power requirement, which is typically about 30 HP. 
     As best shown by comparing  FIGS.  19  and  20   , the destructor  35  and the chopper  9  are formed as a common unit which is movable rearwardly of the combine harvester along a track  401 . The common unit can thus take up the operating position shown in  FIG.  20    where the chopper inlet is aligned with the straw supply duct and the destructor inlet  351  is aligned with the chaff inlet from the sieve  354 . Also the combined unit can move to the rearward position shown in  FIG.  19    where the destructor is moved rearwardly of the combine harvester away from the sieve  354  to allow access to a position between the destructor  35  and the sieve of the combine harvester. This allows the operator to access the sieve by entering an opening  402  in front of the destructor  35  and behind the axle of the combine to visibly inspect the sieve. 
     Thus at least the weed seed destructor section  35  and optionally also the chopper section is slidable on the guide  401  in a rearward direction. The guide  401  includes a pair of tracks each on a respective side wall of the combine harvester and a suitable slide component on the common unit. 
     The drive for the weed seed destruction section is driven from the slow-speed drive of the chopper. A selector on the chopper allows the chopper to operate in either high speed or low speed. Therefore the chopper can be selected to operate in low speed with the weed seed destruction section still operating. Therefore either chopper speed can be selected without effecting the operation of the weed seed destruction section. 
     Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.