[0001] The present invention relates to an apparatus for processing flax straw in which
the high-quality bast fibre is separated from wood parts and bast parts, which apparatus
is provided with one or more beating drums for processing the flax straw.
[0002] These known apparatuses have already been developed some time ago and do not meet
the requirements which are at present imposed in processing tangled flax straw such
as originates, for example, from combines.
[0003] Furthermore, said known apparatuses have only a low capacity and they yield a low-quality
fibre material, i.e. with a high content of contaminants. The known apparatuses can
also virtually not be adjusted, with the result that it is not possible to take account
of variations in the composition of the flax straw. An important disadvantage is,
finally, that the operating costs of the known apparatuses are high in view of the
high investments, the peripheral equipment required and the labour-intensive nature
which are associated therewith.
[0004] The object of the invention is therefore to provide an apparatus of the abovementioned
type which lacks these disadvantages and which is suitable, in particular, for processing
tangled flax straw into a high-quality fibre material. This object is achieved in
the first instance in that a flax straw opener is coupled in upstream of the beating
drum(s), which flax straw opener comprises a toothed ripping roller having a number
of teeth rings and one or more counterknife beams interacting therewith and provided
with knives which project between the teeth rings in a manner such that each teeth
ring interacts with a pair of knives.
[0005] Said flax straw opener processes the tangled straw package supplied in a manner such
that it is intensively pulled open and is uniformly separated. In particular, the
ripping and cutting movements provided by the interaction of the teeth and the knife
beams play an important role in this process. A further effect of the flax straw opener
is the shortening of the fibre material. Finally, a large part of the wooden tubing
is separated; the loose chaffs thereby formed may already possibly be separated then
in a pre-cleaning phase. Depending on the extent to which the flax straw has to be
pulled open and its coarseness, the rotary speed of the ripping roller can be varied,
preferably between 500 and 1,500 revolutions per minute.
[0006] In connection with the supplying and possible slowing down of the flax straw in the
feed to the ripping roller, a positively driven feed roller pair is coupled in upstream
thereof.
[0007] The flax straw material processed in this manner is then fed to a drum comprising
a fixed, rotationally symmetrical shell provided with grate openings and also a rotatable
interior mechanism situated therein and having scutching knives. In said drum, the
material is further pulled open and scutched in order to separate the last wooden
components from the bast fibre. The chaffs and the dust are as far as possible removed
through the grate openings in the shell under the influence of the centrifugal force
and the atmospheric pressure differences generated during rotation.
[0008] Preferably, an embodiment is chosen in which the centre line of the drum is vertical,
the feed for the flax straw to be processed is situated at the bottom and the discharge
of the processed flax straw is situated at the top of the shell, and the shell of
the drum extends in a widening manner from the bottom to the top. The conical shape
promotes the conveyor action of the drum in a favourable sense. If, at the same time,
the scutching knives are situated at an angle in a manner such that they provide an
upwardly directed conveyor action during rotation, the conveyor and separating action
of the drum can be improved still further.
[0009] To promote the removal action of chaffs and dust through the shell, the internal
mechanism is provided with vanes which extend along essentially radial planes to the
shell. If, at the same time, the vanes extend at an angle at their radially outermost
edge to match the shell and are provided at said edge with a row of carding teeth
and the inside of the shell is also provided with at least one row of carding teeth
offset by a half tooth pitch and extending in a plane through the centre line of the
drum, the material can be mechanically carded, in addition, by the mutual interaction
of the rows of carding teeth moving closely over one another.
[0010] The rotary speed of the drum is preferably chosen between 150 and 500 revolutions
per minute.
[0011] At the uppermost end of the internal mechanism, a ring of beating knives is provided
as a ventilator for removing the processed fibre material via the discharge.
[0012] Furthermore, provision can be made that, between the flax straw opener and the drum,
a shaking apparatus is coupled in for removing loose short wood components and also
a breaking apparatus for breaking longer wood components in sequence, and after the
drum, a second shaking apparatus is provided for finally cleaning the processed flax
straw. Such a complete processing line offers the possibility of processing the total
straw crop in tangled form. Despite the fact that the line is technically compact,
it is nevertheless suitable for bulk processing. In addition, the possibility is provided
for responding to variations in the agricultural product, for example by adjusting
the rotational speeds of the flax straw opener and the drum or alternatively by adjusting
the mutual spacing of the carding teeth.
[0013] The invention also relates to a flax straw opener for the apparatus described above.
In particular, it is so constructed that the teeth on the ripping roller have a comparatively
small pitch and those on the feed rollers have a comparatively large pitch so that
the circumferential circles defined by their teeth tips overlap one another with an
offset in the axial direction.
[0014] Finally, the invention relates to a drum for the apparatus described above in which,
in particular, three pairs of scutching knives are provided starting from the bottom
and each pair has in sequence a ring of scutching knives mounted directly on the cylinder
and also a ring of scutching knives mounted on an outermost disc edge.
[0015] The invention will be explained further hereinafter with reference to an exemplary
embodiment shown in the figures.
Figure 1 shows a complete flax processing line in side elevation.
Figure 2 shows the flax straw opener according to the invention, used in the processing
line, in perspective.
Figure 3 shows a plan view of the flax straw opener according to Figure 2.
Figure 4 shows the drum according to the invention used in the processing line according
to Figure 1.
[0016] The processing line depicted in Figure 1 comprises, in sequence in the direction
in which the flax straw to be processed passes through it, a flax straw opener according
to the invention 1, a shaking apparatus 2, a series of fluted rollers 3 for breaking
the flax straw, a drum 4 according to the invention, and, finally, a shaking apparatus
5 over which the flax fibres obtained are removed.
[0017] As is also depicted in Figure 2, the bundles of tangled flax straw are fed via conveyor
belt 34 to a pair of rollers 6 and 16 provided with teeth, via which rollers the flax
straw is fed to ripping roller 7. The uppermost roller 6 of the roller pair is suspended,
so as to move in the vertical direction, on a frame 8 which is partially shown in
Figure 2 and which is pressed by means of a spring 9 in the direction of the lowermost
roller 6. As a result of this, the nip between the rollers 6 and 16 can adjust itself
to the thickness of the bundles of flax straw. Furthermore, the uppermost roller 6,
like the lowermost roller 16, is individually positively driven in a manner not shown,
while the ripping roller 7 is also driven. The rotary speed of the uppermost roller
6, and therefore of the lowermost roller 16, is lower than that of the ripping roller
7, in a manner such that, if the flax straw is gripped by the teeth rings 10 on the
ripping roller 7, the teeth 11 exert a braking action and the teeth 15 on the lowermost
roller 16 a feeding action, in which process the flax straw is uniformly opened and
ripped apart. Situated at the bottom of the ripping roller 7 is furthermore a knife
beam 12 on which knives 13 are mounted at a clearance angle of 10°. At the same time,
each teeth ring is surrounded on either side by a pair of knives 13 which remove the
flax straw entrained by the teeth 10 from the roller and break it further in doing
so. In this process a certain separation occurs of the flax straw fed in into, on
the one hand, fibre components and, on the other hand, wood and bast components.
[0018] In the plan view of the flax straw opener shown in Figure 3 it can be seen that the
teeth 11 are mounted on the uppermost roller 6 with an axial offset with respect to
the matching teeth 15 on the lower roller 16. It can furthermore be seen that the
teeth 10 on the ripping roller 7 extend to inbetween the teeth 11 and 15.
[0019] From the flax straw opener 1, the processed flax straw material is fed to the shaking
apparatus 2 where a portion of the finer waste is removed by shaking. This then falls
onto the belt 14 and is removed therewith.
[0020] From the shaking apparatus 2, the material enters between the series of fluted rollers
17 where the larger flax straw components are broken. This process is known per se.
[0021] Then the material is fed to the drum 4 which is shown in more detail in Figure 4.
The drum comprises a conical shell 18 in which an internal mechanism 19 is rotatably
mounted. The internal mechanism is driven by means of a motor 20 and a belt transmission
21.
[0022] The flax straw material is fed via the lowermost feed opening 33 to the interior
of the shell 18. During the rotation of the internal mechanism 19, the flax straw
is then scutched by the scutching knives 23 and 24 mounted on the central shaft 22
of the internal mechanism 19. Said scutching knives are arranged at an angle in the
manner of turbine blades in a manner such that an upwardly directed conveyor action
is generated. In this connection, the scutching knives 23 are mounted directly on
the shaft 22, while the scutching knives 24 are mounted on a disc 25 extending radially
with respect to the shaft 22. On said disc 25 and the shaft 22 vanes 26 are furthermore
provided which have the object, during the rotation of the internal mechanism 19,
of forcing the waste material outwards through the grate openings in the shell 18
under the influence of the atmospheric pressure differences thereby generated.
[0023] As depicted, the drum according to the invention has three sets of scutching knives
23 and 24 with a disc 25 arranged above one another. In conjunction with the conical
shape of the shell 18, all these scutching knives 23, 24 ensure an upward conveyor
flow. Finally, at the top of the drum, the material is removed by means of the beating
knives 26, also arranged at an angle, through the discharge opening 27 situated at
the top.
[0024] As depicted, further vanes 28 are mounted between the centremost and uppermost disc
25, which vanes extend by means of their radially outermost edge to a point near the
inside circumference of the shell 18 and are provided at that point with a row of
carding teeth 29. Mounted on the internal circumference of the shell 18 are three
matchingly constructed rows of carding teeth 30 which are offset by a half tooth pitch.
These can be adjusted towards the shaft and are arranged in a somewhat tapering manner.
When the material is now fed up through the drum from the lowermost feed 33 to the
uppermost discharge 27, the fibres are mechanically carded by the mutually interacting
rows of carding teeth 29 and 30. Such rows of carding teeth may also be situated on
the vanes 26 and the wall components, situated opposite, of the shell 18. At the same
time, the material is forced towards the shell 18 during this conveyor movement under
the influence of the centrifugal force and atmospheric pressure differences generated
during rotation of the shaft 22 in a manner such that contaminants emerge outwards
through the grate openings in the shell 18. In this connection, the grate openings
are formed in the lowermost part of the shell 18 between grate rods 31 extending along
lines describing a cone and in the uppermost portion by constructing the wall in so-called
pressed-through gauze 32 with the smooth side facing inwards. This removed material
also then comes to rest on the belt 14 which also extends beneath the drum.
[0025] From the discharge 27, the fibre material now obtained is conveyed over the shaking
apparatus 5 where contaminants still present may be further removed.
1. Apparatus for processing flax straw in which the high-quality bast fibre is separated
from wood components and bast components, which apparatus is provided with one or
more beating drums for opening the flax straw, characterized in that a flax straw
opener is coupled in upstream of the beating drums, which flax straw opener comprises
a toothed ripping roller having a number of teeth rings and one or more counterknife
beams interacting therewith and provided with knives which project between the teeth
rings in a manner such that each teeth ring interacts with a pair of knives.
2. Apparatus according to Claim 1, wherein the knives make a clearance angle of approximately
10° with respect to the lateral surface of the ripping roller.
3. Apparatus according to one of the preceding claims, wherein a toothed, positively
driven feed roller pair is coupled in upstream of the ripping roller.
4. Apparatus according to Claim 3, wherein the uppermost roller of the feed roller
pair is suspended in a pivotable spring-loaded bracket which is pressed towards the
lowermost roller in a manner such that the nip between the two rollers is variable.
5. Apparatus according to one of the preceding claims, wherein the beating drum comprises
a fixed, rotationally symmetrical shell provided with grate openings and also a rotatable
internal mechanism situated therein and having scutching knives.
6. Apparatus according to Claim 5, wherein the centre line of the drum is vertical,
the feed for the flax straw to be processed is situated at the bottom and the discharge
of the processed flax straw is situated at the top of the shell.
7. Apparatus according to Claim 6, wherein the shell of the drum extends in a widening
manner from the bottom to the top.
8. Apparatus according to Claim 6 or 7, wherein the scutching knives are arranged
at an angle in a manner such that they provide an upwardly directed conveyor action
during rotation of the rotatable internal mechanism.
9. Apparatus according to Claim 6, 7 or 8, wherein the internal mechanism is provided
with vanes extending along essentially radial planes to the shell.
10. Apparatus according to Claim 9, wherein the vanes extend at an angle at their
radially outermost edge to match the shell and are provided at said edge with a row
of carding teeth and the inside of the shell is also provided with at least one row
of carding teeth offset by a half tooth pitch and extending in a plane through the
drum centre line.
11. Apparatus according to Claim 10, wherein the internal mechanism is provided with
one or more sets of three vanes regularly distributed in the direction of rotation
and the shell is provided with three matchingly distributed rows.
12. Apparatus according to Claim 10 or 11, wherein the carding teeth rows on the shell
are radially adjustable.
13. Apparatus according to one of Claims 5 to 12 inclusively, wherein the internal
mechanism is an essentially cylindrical shaft provided with external concentric discs
extending radially at the top to some distance from the shell.
14. Apparatus according to Claim 13, wherein certain scutching knives are mounted
on the radially outermost edge of the discs and others directly on the shaft.
15. Apparatus according to one of Claims 5 to 14 inclusively, wherein a ring of beating
knives is provided at the uppermost end of the internal mechanism as a ventilator
for removing the processed flax straw via the discharge.
16. Apparatus according to one of the preceding claims, wherein in sequence between
the flax straw opener and the drum, a shaking apparatus is coupled in for removing
loose short wood components and also a breaking apparatus for breaking longer wood
components.
17. Apparatus according to Claim 16, wherein a second shaking apparatus is provided
downstream of the drum for finally cleaning the processed flax straw.
18. Apparatus according to one of the preceding claims, wherein the rotary speed of
the ripping roller is variable between 500 and 1,500 revolutions per minute.
19. Apparatus according to one of the preceding claims, wherein the rotary speed of
the drum is variable between 150 and 500 revolutions per minute.
20. Flax straw opener for an apparatus according to one of the preceding claims.
21. Flax straw opener according to Claim 20, wherein the teeth on the ripping roller
have a comparatively small pitch and those on the feed rollers have a comparatively
large pitch, the circumferential circles defined by their teeth tips overlapping one
another with an offset in the axial direction.
22. Drum for an apparatus according to one of Claims 5 to 19 inclusively.
23. Drum for an apparatus according to Claim 14, wherein three pairs of scutching
knives are provided starting from the bottom and each pair has in sequence a ring
of scutching knives mounted directly on the cylinder and also a ring of scutching
knives mounted on an outermost disc edge.
24. Drum according to Claim 23, wherein the lowermost portion of the shell comprises
rods extending according to lines describing a cone and the uppermost portion comprises
gauze pressed-through on one side to the outside.