Weed seed destruction

Abstract

Weed seeds are destroyed in the chaff from a combine harvester by repeated high speed impacts caused by a rotor which accelerates the discarded seeds in a direction centrifugally away from the rotor onto a stator including angularly adjustable stator surfaces around the axis. Thus the discarded seeds rebound back and forth between the rotor and the stator to provide a plurality of impacts. The destructor is mounted on or coaxially with a suitable drive shaft in the straw stream such as the chopper rotor shaft. The rotor is mounted on bearings relative to the chopper rotor drive shaft and is coupled thereto by a releasable coupling between plates radial to the shaft so that the rotor can be stopped while the chopper rotor continues to operate in the event of a fault in the weed seed destructor.

1 . A combine harvester comprising:
 a separation system including a threshing system which separates harvested crop into a first material stream comprising straw and a second material stream comprising chaff and weed seeds;   a rotary member mounted on the combine harvester for rotation about a rotary axis;   wherein the rotary member carries a plurality of straw engaging members engaging the straw in the first material stream;   and at least one weed seed destructor section comprising:
 an inlet receiving the chaff and weed seeds in the second material stream; 
 a first rotor having first rotor surfaces engaging the chaff and weed seeds in the second material stream; 
 the first rotor being mounted for rotation about a rotor axis of said at least one weed seed destructor section; 
 second stator surfaces engaging the chaff and weed seeds in the second material stream; 
 the first rotor being mounted so that said rotation of the first rotor relative to the second stator surfaces causing the chaff and weed seeds to be impacted between said first rotor and second stator surfaces so that the weed seeds in the second material are devitalized before being spread onto the ground; 
   wherein the rotor axis of said at least one weed seed destructor section is coaxial with the rotary axis of the rotary member for rotation about a common axis;   wherein the rotor of said at least one weed seed destructor section is connected by one or more connecting elements to the rotary member for common rotation about the common axis;   and wherein said one or more connecting elements are releasable to allow the rotor of said at least one weed seed destructor section to remain stationary while the rotary member rotates about the common axis.   
     
     
         2 . The combine harvester according to  claim 1  wherein the rotary member includes a shaft component along the common axis and wherein the rotor of said at least one weed seed destructor section is mounted on the shaft component. 
     
     
         3 . The combine harvester according to  claim 2  wherein the rotor of said at least one weed seed destructor section is mounted on the shaft component by a bearing to allow the shaft to rotate with the rotary member while the rotor of said at least one weed seed destructor section remains stationary. 
     
     
         4 . The combine harvester according to  claim 1  wherein the rotary member includes a plate member lying in a radial plane of the common axis at the rotor of said at least one weed seed destructor section and wherein the rotor of said at least one weed seed destructor section is fastened to the plate member by said connecting elements. 
     
     
         5 . The combine harvester according to  claim 4  wherein the connecting elements comprise axially extending releasable screw fasteners passing through a portion of the rotor of said at least one weed seed destructor section into the plate member. 
     
     
         6 . The combine harvester according to  claim 1  wherein said at least one weed seed destructor section is located at a position axially separated from the straw engaging members. 
     
     
         7 . The combine harvester according to  claim 1  wherein said at least one weed seed destructor section is located at an end of the rotary member. 
     
     
         8 . The combine harvester according to  claim 1  wherein said at least one weed seed destructor section comprises a first weed seed destructor section at a first end of the rotary member and a second weed seed destructor section at a second end of the rotary member. 
     
     
         9 . The combine harvester according to  claim 1  wherein the rotary member is a rear straw chopper and carries a plurality of straw chopping blades at axially spaced locations therealong. 
     
     
         10 . The combine harvester according to  claim 1  wherein the rotary member is an internal straw chopper and carries a plurality of straw chopping blades at axially spaced locations therealong. 
     
     
         11 . The combine harvester according to  claim 1  wherein the rotor of said at least one weed seed destructor section includes an inner rotor component and at least one coaxial surrounding ring of rotor components and wherein the stator surfaces comprise at least one coaxial ring of stator surfaces located between the inner rotor components and the ring. 
     
     
         12 . The combine harvester according to  claim 1  wherein said at least one weed seed destructor section includes a common discharge with a discharge for the first material. 
     
     
         13 . The combine harvester according to  claim 1  wherein said at least one weed seed destructor section is arranged to expel the second material into a secondary spreading device. 
     
     
         14 . The combine harvester according to  claim 13  wherein the secondary spreading device comprises a tailboard with a plurality of fins. 
     
     
         15 . The combine harvester according to  claim 1  wherein there is provided a transfer system to move the second material from a discharge location to said at least one weed seed destructor section wherein the rotary member and the transfer system are driven by a common drive system and wherein the transfer system drive can be decoupled from the common drive. 
     
     
         16 . The combine harvester according to  claim 15  wherein there is provided a bypass by which the second material can bypass the transfer system.