Note: Descriptions are shown in the official language in which they were submitted.
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VENTING OF A COMBINE HARVESTER
This invention relates to a combine harvester and to arrangements for
reducing the pressure differential between the internal body of the combine
harvester and the exterior.
BACKGROUND OF THE INVENTION
Combine development in recent years have put greater demands on
the straw choppers and chaff spreaders. The main reasons are that larger
combines
and wider cutting widths are creating higher flows of straw and chaff; wider
cutting
widths create more demanding spreading widths; reduced tilling practices have
put
more demand on even spreading of both straw and chaff and that plant breeding
has
resulted in tougher straw, higher yields and more residue.
Large capacity combines have remained the same physical size as
previous models. This means that a greater flow of grain, chaff and straw are
moving through the same sized cavities. For this reason, greater mass flows of
air
are required to separate the chaff and grain on the sieves and in advanced
straw
chopping systems, a greater volume of air is being pressurized to spread the
residue
wider. This means that there must be a large exhaust I inlet area to balance
the
airflow so that the combine hood will not pressurize and effect grain
separation.
As combines get larger and more compact the distance between the
end of the sieve and the straw chopper is shrinking as this space is
sacrificed for
other options. The space between the chopper and the sieve end typicaNy is the
area where air pressure is balanced. Reduction of and enclosing of this space
has
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the potential to create problems with the airflow off of the sieves and
therefore after
the grain sample - leaving poorly separated grain or a dirty sample.
Typically the airflow off the sieves carries the chaff and light partials
into a chaff spinner or straw chopper. The airflow trajectory needs to remain
substantially rearward so it will not create vortices or non laminar flow
across the
sieves with the potential of creating a dirty sample.
The current John Deere STS combine is perhaps the most extreme
example of a compact machine. In this case Deere has added a small opening in
the sidewaN of the combine, nearly perpendicular to the end of the sieves and
substantially immediately at the end of the sieves. Although in one condition
this
does relieve some air pressure, the placement of the opening interferes with
the
proper operation of the sieves in that the air from the sieves must make a
substantially immediate 90-degree turn as it comes off of the sieves. This
leads to
vortices on the sieves and uttimately to areas of the sieves that contribute
to a poor
grain sample. Inversely, when the chopper is demanding more air than is being
supplied by the sieve fan the air must be drawn in from a location near the
sieves
which again leads to vortices on the sieves and ultimately to areas of the
sieves that
contribute to a poor grain sample.
At this time no other solution is available which will allow the large
amount of air exiting 1 drawn in the rear of the sieves to escape / enter the
combine.
US Patent 4,412,549 (Rowland Hill) issued November 1983 and US
Patent 6,558,252 (Visagie) issued May 2003 both disclose air flow arrangements
which improve separation at the sieve in the combine harvester.
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$UMMARY OF THE INVENTION
It is one object of the invention to provide an improved combine
harvester and/or an apparatus which can be used with a combine harvester in
which
the air flow is not compromised,
According to one aspect of the invention there is provided a combine
harvester comprising:
a housing;
a straw separating system mounted within the housing for separating
seed materials from straw for collection of the seed materiais and for
transport of the
straw rearwardly toward a rear of the housing for discharge;
the housing having a mar hood with walls defining a hollow interior,
and separating the hollow interior from an exterior of the combine harvester,
into
which hollow interior straw from the separating system is fed and with a
bottom
opening in the rear hood for discharge of the straw from the hollow interior
of the
rear hood;
a straw chopper mounted at the rear hood for receiving the straw from
the hollow interior of the rear hood;
the straw chopper having a generally cylindrical rotor with a hub
mounted for rotation about a horizontal axis and carrying blades for chopping
the
straw and for generating an air stream for spreading the chopped straw;
the straw chopper having a chopper housing defining an inlet opening
at the rotor for receiving straw moving downstream from the hollow interior of
the
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rear hood and an outlet opening angularly spaced around the rotor from the
inlet
opening for discharge of the chopped straw in the air stream;
and at least one vent opening arranged to allow air to pass between
the hollow Interior of the rear hood at a position upstream of the inlet
opening and
the exterior through said at least one opening.
In one arrangement the at least one vent opening includes an opening
located in a wall of the rear hood adjacent the straw chopper.
Preferably the at least one vent opening includes a first and a second
vent opening each arranged in a respective side wall of the rear hood adjacent
the
straw chopper.
In another arrangement, the chopper housing includes housing walls
attached to the rear hood and depending therefrom and wherein the at least one
vent opening includes an opening located in a respective one of the chopper
housing walls.
Preferably the chopper housing walls include two side walls and
wherein there is a respective one of the vent openings in each side wall.
Preferably the chopper housing walls each include a mounting flange
at its top edge for attachment to the bottom of the hood and wherein the at
least one
vent opening includes a plurality of horizontal slots at spaced positions
directly below
the mounting flange.
Preferably the chopper housing includes a rear wall extending
transversely across the rear hood and wherein there is provided a vent opening
in
the rear wall.
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Preferably the vent opening in the rear wail include a plurality of
horizontal siots.
Preferably the at least one vent opening includes a plurality of louvers.
Preferably the louvers are arranged such that they are inclined
upwardly and outwardly so as to be angled opposite to the downward direction
of
flow of the straw.
Preferably the there is provided a pneumatic fan having a duct
connected to the at least one vent opening for driving air through the at
least one
vent opening.
Preferably the fan has an outlet duct which transports the air from the
fan to be mixed with the air stream from the rotor.
According to a second aspect of the invention there is provided an
apparatus for mounting on a combine harvester having: a housing; a straw
separating system mounted within the housing for separating seed materiais
from
straw for collection of the seed materiais and for transport of the straw
rearwardly
toward a rear of the housing for discharge; the housing having a rear hood
with a
bottom opening in the hood for discharge of the straw and the lighter
materials;
the apparatus comprising a straw chopper having a housing arranged
to be mounted at the rear hood for receiving the straw, the housing having
walls for
attachment to the rear hood so as to depend therefrom;
the straw chopper having a generally cylindrical rotor with a hub
mounted for rotation about a horizontal axis and carrying blades for chopping
the
straw and for generating a an air stream for spreading the chopped straw;
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the chopper housing defining an inlet opening at the rotor for receiving
straw moving downstream from the hollow interior of the rear hood and an
outlet
opening angularly spaced around the rotor from the inlet opening for discharge
of
the chopped straw in the air stream;
and at least one vent opening in at least one of the walls of the
chopper housing arranged to allow air to pass between the hollow interior of
the rear
hood at a position upstream of the inlet opening and the exterior through said
at
least one opening.
According to a third aspect of the invention there is provided a combine
harvester comprising:
a housing;
a straw separating system mounted within the housing for separating
seed materials from straw for collection of the seed materials and for
transport of the
straw toward the outlet of the housing for discharge;
the housing having a rear hood with walls defining a hollow interior,
and separating the hollow interior from an exterior of the combine harvester,
into
which hollow interior straw from the separating system Is fed and with a
bottom
opening in the rear hood for discharge of the straw from the hollow interior
of the
rear hood;
a straw chopper mounted at the hood for receiving the straw for
chopping the straw and for generating an air stream for spreading the chopped
straw;
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the straw chopper having a transverse hub rotatable about a
transverse axis and carrying a plurality of axially spaced blades for rotation
with the
hub about the axis so as to define an imaginary vertical plane parallel to and
in front
of the axis which is the forwardmost plane which tips of the blades reach;
the straw chopper having a chopper housing defining an inlet opening
at the rotor for receiving straw moving downstream from the hollow interior of
the
rear hood and an outlet opening angularly spaced around the rotor from the
inlet
opening for discharge of the chopped straw in the air stream;
and at least one vent opening having at least a portion thereof
rearward of said imaginary vertical plane and arranged to allow air to pass
between
the hollow interior of the rear hood at a position upstream of the inlet
opening and
the exterior through said at least one opening.
According to a fourth aspect of the invention there is provided a
combine harvester comprising:
a housing;
a straw separating system mounted within the housing for separating
seed materials from straw for collection of the seed materials and for
transport of the
straw rearwardly toward a rear of the housing for discharge;
the housing having side walls defining a hollow interior, and separating
the hollow interior from an exterior of the combine harvester, into which
hollow
interior straw from the separating system is fed and with an opening for
discharge of
the straw from the hollow interior;
a straw chopper for reoeiving the straw from the hollow interior;
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the straw chopper having a generally cylindrical rotor with a hub
mounted for rotation about a horizontal axis and carrying blades for chopping
the
straw and for generating an air stream for spreading the chopped straw;
the straw chopper defining an inlet opening at the rotor for receiving
straw moving downstream from the hollow interior of the rear hood and an
outlet
opening angularly spaced around the rotor from the inlet opening for discharge
of
the chopped straw in the air stream;
and at least one vent opening in at least one of the side welis of the
housing arranged to allow air to pass between the hollow interior at a
position
upstream of the inlet opening and the exterior through said at least one
opening.
BRIEF DESGRIPTION OF THE DRAWINGS
Figure 1 is a schematic side elevational view of a combine harvester
and straw chopper according to the present invention.
Figure 2 is a schematic side elevational view similar to that of Figure 1
showing the intemal components in phantom.
Figure 3 is an isometric view of the straw chopper and combine of
Figure 1.
Figure 4 is an isometric of the chopper alone and including a rear vent
cover.
Figure 5 is a similar Isometric view showing an arrangement with vent
openings both in the rear wall and side walls of the chopper housing, with the
rear
vent cover removed.
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Figure 6 is a top plan view of the chopper of Figure 3 showing a duct
and fan arrangement for transporting the vented air,
Figure 7 is an isometric view similar to that of Figure 3 showing an
arrangement in which the vent opening are in the side walls of the rear hood.
Figure 8 is a side elevational view of an arrangement using an internal
chopper in which the vent openings are arranged in the side walls of the
chopper.
DETAILED DESCRIP_TION.
A combine harvester shown in Figure 1 comprises a combine
harvester housing 10 mounted on ground wheels 11 for transport over a ground
in
conventional manner. The combine harvester is shown only schematically sinoe
many different designs are available and well known to one skilled in the art.
The
combine harvester includes a straw separation section generally indicated at
12 and
a sieve section generally indicated at 13. Again these elements are
conventional
and provide arrangements for separation of the straw from the crop material
allowing
the seed material to fall through to the sieve at which seeds are separated
from the
seed material leaving the chaff or other lighter materials on top of the sieve
to be
carried away from the sieve by an air flow through the sieve as is well known.
The rear of the combine is provided is a rear hood 14 into which air
from the straw separation system and the sieves enters and into which straw is
discharged rearwardly for and is guided by guide wall 14A and by operable
guide
panel 148 in the hood section 14 into a chopper and spreader generally
indicated at
15.
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This arrangement is well known and commercial products are readily
available from Redekop Manufacturing and other manufacturers of straw choppers
of this type.
The chaff from the rear end of the sieve as best shown in Figure 2 at
5 13 is carried by a movable pan 16 and a chaff control door 16A into the
inlet 32 of
the chopper 14.
An example of a chopper of this type is disclosed in US Patents
6,478,674 issued Nov 12th 2002, 5,482,508 issued Jan 9th 1996 and 5,232,405
issued August 3d 1993 all of Leo Redekop, and US application 2002/0004417
10 published Jan 4D"' 2002 the disclosures of which are incorporated herein by
reference.
The chopper has a horizontal upper mounting flange 25 which attaches
to a corresponding bottom flange of the hood of the combine. This forms a
rectangular open mouth at the top of the chopper which corresponds in shape to
the
rectangular lower opening of the hood so that all material discharging from
the guide
walls 14A and 14B falls into the upper part of the housing and enters the
inlet 32 of
the chopper.
The chopper comprises a housing attached to the top mounting flange
and depending therefrom and defined by side wails 26 at opposite sides of the
hood
and generally co-planar therewith. Bridging the side walls 26 is provided a
bottom
wall 22 and a top wall 21 which extend across the width of the chopper and
form a
generally cylindrical containing surfaoe for receiving the chopper rotor 20.
The rotor
20 includes a hub 28 with a plurality of radially extending flails or blades
29 carried
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on the rotor for rotation therewith around the axis of the rotor which is
arranged
across the width of the chopper.
Many different arrangements and construction of blades can be used
as are well known to one skilled in the art and described in the above patents
of
Redekop. In most cases the chopper includes stationary blades 30 mounted on
the
bottom wall 22 at a position partway around the bottom wall. The stationary
blades
are arranged in a row at spaced positions across the width of the chopper so
as to
co-operate with the rotating blades of the hub in a chopping action. The
spacing
between the blades can be selected in acoordance wrth the type of rotating
blades
as Is well known to one skilled in the art.
The top wall 21 and the bottom wall 22 define at the upper part of the
housing the inlet 32 into which the straw can be guided from the hood and from
the
sieve 13. The chaff guide plate 16 and control door 16A carry the chaff fnom
the end
of the sieve over the space between the end of the sieve and the front edge 36
of
the bottom wall 22 so as to carry the chaff in the air stream from the sieve
over the
plate and into the opening 32.
In the configuration shown, the top wall 21 includes a generally vertical
portion 37 which extends downwardly from the top flange 25 to the top of the
rotor.
The top wall 21 further includes a curved section 38 which extends around the
top of
the rotor to a rear edge 39 which defines the top edge of the rear discharge
opening
40 through which the material exits in the stream of air and chopped materials
generated by the rotation of the rotor within the housing.
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A taifboard 41 is pivotally mounted on the rear part of the housing at a
pivot mount 41A. The tailboard comprises a base plate 42 with a series of fins
43 on
the underside shaped and arranged so that material exiting from the discharge
opening 40 is thrown up against the underside of the tailboard and impacts the
fins
causing a change in direction of the material on the tailboard so as to spread
the
material using the momentum generated in the stream from the rotor. The angle
of
the tailboard can be adjusted around the pivot 41A by positioning a spring
loaded
pin. The load of the tailboard is counteracted with a gas cylinder 44.
Rear vents 115 and side vents 116 are provided in the chopper
housing. In Figures 3 and 4 the rear vents 115 are covered by an inclined rear
cover
panel 125 which is removable. In this configuration the vents form a series of
horizontal parallel slots in the side wall wi#h the first immediately at the
top mounting
flange. The vents consist of louvers that are angled outwards and upwards, as
best
shown in the isometric views, so as to be opposite to the downwards direction
of the
straw flow path. This is necessary to eliminate straw from plugging the vent
holes.
The vents can be provided solely in the side walls of the chopper housing or
can be
provided solely in the rear walf or in both. The vents are above and forward
of the
inlet 32 so as to act on the air in advance of the materials entering the
inlet of the
chopper. As shown in Figure 2, the straw chopper has a transverse hub
rotatable
about a transverse axis and carrying a plurality of axially spaced blades for
rotation
with the hub about the axis so as to define an imaginary vertical plane marked
at IP
parallel to and in front of the axis A which is the forwardmost plane which
tips of the
blades 29 reach.
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The side vent openings 116 have at least a portion thereof rearward of
the imaginary vertical plane IP and arranged to allow air to pass between the
rear
hood and the exterior through the at least one vent opening. Thus each slot
defining
the vent openings includes a part of the slot which is rearward of the plane
IP and
part in front. The slots at the top are longer so as to include a longer part
rearward.
The slots are symmetrical about a center line so that they gradually become
shorter
from the uppermost slot at the flange 25 to the bottom slot blow the top of
the rotor,
The vents are located above the chopper rotor and particularly above
the inlet thereto so that the air which is not drawn into the inlet because of
pressurization in the hood can escape through the vents. Inversely, if the
chopper is
drawing more air than is being supplied by the sieves, air will be drawn in,
through
the vents, thereby not limiting the chopper's performance and also not drawing
additional air from the sieves and grain with it.
It is important to note that the vents do not need to be in the chopper
housing. The vents can be placed in the hood of the combine substantially
close to
the chopper or immediately above the mounting flange of the chopper as shown
at
vents 136 in Figure 7. The air should be vented I drawn-in as close as
possible to
the chopper so that the air moving rearwardly from the rear end of the straw
separation system and rearwardly from the rear edge of the sieve assembly
carries
the chaff and straw to the chopper assembly.
The vents also may be partly in the hood and partly in the chopper. As
shown the vents are preferably louvers but there could be many possible shapes
such as round like a cheese grater. The important part of the construction is
that
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there is a void to aiiow' air either In or out, with some mechanism to stop
the straw
from coming out or it plugging in the void. The holes are preferably oriented
perpendicular to the direction of the straw flow so as to better control the
escape of
air without allowing straw to enter the vent with the potential of plugging.
As shown in Figure 6 the vents in the side wall are connected to the
inlet duct 145 of a pneumatic fan 150 mounted to draw air out of the combine
hood
thereby reducing the pressurized effect. The outlet of the fan provides
pressurized
air to a duct 151 which increases in width to a slot 152 at the discharge 40
to assist
in providing an increased air flow from the discharge over the fins of the
tailboard for
spreading. Referenee is made to co-pending Appliaetion Serial Number not yet
known (Attorney Docket Number 83416-702) which is based on Canadian
Application 2,440,082 filed September gth 2003, which discloses the use of a
fan to
generate air flow boost to be supplied to the chopper and the intake duct
shown in
Figure 1 can be used with such a fan to provide additionai air for the
discharge of the
chopper.
As shown in Figure 8 an altemative conventional arrangement well
know to one skilled in the art is shown where an internal chopper 200 is
provided in
the combine body above the sieve 13 and in front of the hood 14. This
arrangement
has inlet openings corresponding to the inlet openings 201 described herein
located
in relation to the chopper and constructed as previously described. .
Since various modifications can be made in my invention as herein
above described, and many apparently wideiy different embodiments of same made
within the spirit and scope of the claims without department from such spirit
and
CA 02465143 2006-11-30
scope, it Is Intended that all matter oontained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
