Note: Descriptions are shown in the official language in which they were submitted.
2~ aos ~3
A METHOD AND AN APPARATUS FOI~ COMPACTING MATERIAL
TECHNICAL FIELD
The present invention relates to an apparatus for
receiving and compacting material.
BACKGROUND ART
There is a need in this art to be able to compact
material which includes components of various sizes,
densities, elasticity, moisture content etc.
Material of the type mentioned by way of introduction
is often massive and bulky and needs to be compressed
or compacted in order to be capable of being handled
and transported in an economically viable manner.
Such needs occur, for example, in industrial
operations and in municipal waste disposal, for
example in refuse collection. For wet matter, it is
also often desirable to reduce the moisture content
of the material in connection with its compression
(compaction).
Prior art technology calls for the employment of
hydraulic compactors for compacting material of the
above-disclosed type. Hydraulic compactors are
expensive, unwieldly and heavy, in addition to which
the reduction in volume which is obtained is
relatively slight. As regards, for example, domestic
or commercial waste, the reduction involved is no
greater than a factor of 3. This slight degree of
compaction is because all material to be found in the
transport container is compacted at the same time.
For compaction purposes, us~a is also made of screw
compactors consisting of a mechanical shaft which is
fitted with thread blades and is surrounded by a
tubular casing. Compaction is achieved in that the
screw compactor presses the material into a container
which is
WO 93/09936 ~~ ~ ~~"~ '~ PCT/SE92/008024
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filled in due course. L~!hen the container has been filled, the screw
compactor is employed to continue to 'Force material into the
container and there is thereby obtained a certain degree of
compression of the material which is located in the container.
However, the level of compaction is relatively slight: nor does this
technique exceed a level of compaction of a factor 3. The explanation
for the slight degree of compaction is that those pressure forces
which are exercised by the screw compactor are absorbed by
substantially all material located in the container, with the result
that those forces which act on each individual component vrill,
naturally be relatively slight. Screw compactors have relatively lour
capacity in relation to their size, suffer from difficulties in
handling large objects and require considerable po~,~er for their
operation. In addition, screw compactors are large and heavy, as ~~rell
as being expensive in both purchase and operation.
Spiral compactors are also employed for compacting material. The term
spiral compactor is here taken to signify compactors including a
spiral which is rotary about its longitudinal axis, vrhich lacks a
mechanical shaft and which includes a spiral or helical blade stood
on its end and surrounded by a casing. In such instance, the spiral
and the casing form a precompaction zone where compaction of the
material commences. In the precompaction zone the spiral has an outer
diameter which is slightly less than the inner diameter of the
casing. Thereby, the spiral closely approaches (vrith slight
clearance) the surrounding casing. The precompaction zone is
followed, in the direction of displacement of the material, by a
region which has no spiral and in vrhich the final compaction of the
material takes place.
Spiral compactors have a relatively simple design and construction
which results in low practical and running costs, at the same time as
the degree of compaction is considerably better than the
above-disclosed factor of 3. The construction of spiral compactors
described in the preceding paragraph (slight clearance between casing
and spiral) entails, however, the disadvantage that, on varying
material size, the material is occasionally jammed between the spiral
21 006 73
and the casing. In particular when large-piece
material is involved, blockages readily occur, with
resultant operational disturbance or operational
disruption.
SUMMARY OF THE INVENTION
Therefore, in accordance w:ith the present invention,
there is provided an apparatus for compacting
material comprising a casing defining an infeed
opening and a discharge opening, at least one
shaftless spiral member disposed in said casing and
having a longitudinal axis, said shaftless spiral
member comprising a spiral blade, drive means
connected to a first end of said shaftless spiral
member for rotating said shaftless spiral member
around said longitudinal axis thereof, a feed
compartment formed by said shaftless spiral member
and said casing, said casing defining a chamber
between said infeed opening and said discharge
opening, said chamber inc7_uding a shaftless spiral
member free region defining a compaction cell
proximate said discharge opening, said shaftless
member being journalled solely at said first end
portion thereof, baffle means disposed in association
with said discharge opening for impeding displacement
of material advanced through said apparatus, and at
least one mechanical guide member disposed in said
casing upstream of said shaftless spiral member in
the region of said infeed opening.
Also in accordance with the present invention, there
is provided an apparatus for compacting material
comprising:
a casing having an infeed opening for material
to be compacted,
a rotatable shaftles~, spiral in said casing
having a longitudinal axis c>f rotation,
drive means drivingly connected to one end of
said spiral for rotating said spiral around said
longitudinal axis of rotation,
said spiral having an opposite end which is free
and unsupported in said casing,
said casing defining a feed compartment having a
longitudinal length substantially equal to a
longitudinal length of said infeed opening,
said casing further defining a compaction cell
extending in longitudinal continuation of said feed
compartment and directly merging therewith at a
transition between said feed compartment and said
compaction cell,
said opposite free end of said spiral being
disposed in the region of: said transition between
said feed compartment and s<~id compaction cell,
said compaction cell having a discharge outlet
spaced longitudinally from said transition, and
baffle means at said discharge outlet of said
compaction cell for opposing displacement of said
material and discharge thereof from said outlet.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The present invention will now be described in
greater detail hereinbelow, with particular reference
to the accompanying drawings. In the accompanying
drawings:
Fig. 1 shows one embodimE~nt of a spiral compactor
cut away in the longitudinal direction,
provided with but a single spiral;
Fig. 2 shows a section taken along the line II-II
in Fig. 1;
Fig. 3 shows a section taken along the line III-III
in Fig. 1;
3x> 2100673
Fig. 4 shows another embodiment of a spiral
compactor cut away in the longitudinal
direction, with twc> spirals;
Fig. 5 shows a section taken along the line V-V in
Fig. 4; and
Fig. 6 shows a section taken along the line VI-VI
in Fig. 4.
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DESCRIPTION OF PREFERRED EM80DIMENT
Figs. 1-3 show one embodiment of an apparatus according to the
present invention including a spiral 30 :which is placed in path 10.
The spiral is rotary about its geometric centre axis 31, The path has
a lower portion 26 vrhich is of a cross-section entailing that the
lower region surrounds the spiral with relatively slight clearance.
In the embodiment illustrated in Fig. 2, the cross-section of the
lower portion is semicircular, in addition to vrhich the lower portion
merges into two substantially upstanding walls 2~a,b, which form the
upper portion 27 of the path. The one end 34 of the spiral, its
driving end, is connected, via a journal 16 in the one end, the drive
end of the path 10, to drive means 60 for rotating the spiral. The
spiral 30 includes a spiral blade 33 which is stood on its end and
is, in the illustrated embodiment, composed of an inner part spiral
blade 37 and an outer part spiral blade 3v connected vrith the inner
part spiral blade. The arrows ~ indicate the direction of rotation of
the spiral.
The spiral blade 33 is journalled only in connection vrith its drive
means G0, while its other end 39 is non-journalled. hereinafter, the
non-journalled end :rill generally be designated the free end 39 of
the spiral blade or the spiral. The free end 39 is located in or
adjacent the discharge end 43 of the path. The jornal 16 is placed
such that the spiral blade 33 rotates, most proximal the journal lv,
without any mechanical contact with 'the lover portion 26 of the path
or with the upvrardly directed walls ~?2a,b of the path. On rotetion,
the spiral is disposed, with the exception of its portion located
most proximally the journal, to abut with its outer defining edge 32,
against the lover portion 20 of the path 10. However, as a rule the
spiral blade abuts against only a limited region of the loner portion
of the path, defined as that region of the lower portion with which
the spiral blade 33 during rotation progressively alters its
direction of movement from being substantially vertical to being
substantially horizontal. This side of the path against which the
spiral substantially abuts will hereafter be designated the support
side. It is clear that, on rotation of the spiral blade, material
particles are often entrained between the path and the
WO 93/09936 21 0 0 6 7 3 , PCT/SE92/00802
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defining edge and also often form a i~f~~'~ayer of material between
the spiral blade and the path. As a result, in operation, abutment
between the spiral blade and the path is intermittent. Elowever, for
the sake of simplicity it will hereinafter be disclosed that the
spiral blade abuts against the path or is supported by the path 10
irrespective of whether the spiral blade 33 is in direct contact with
the path or in contact via a material layer located between the
spiral blade and the path. In order to achieve the sought-for
abutment against the path, the journal if and the spiral hlade 33
are, as a rule, designed so as, on heavy loading, to alloy; the spiral
to be resiliently displaced in a radial direction.
On abutment of the spiral 30 against the path 10, the outer defining
edge 32 of the spiral is substantially parallel with the inner
defining surface of the path. As a result of the elasticity of the
spiral in the radial direction, the spiral will, on rotation,
progressively abut v:ith its outer defining edge 32 against the pith
along the greater portion of the length of the spiral according as
the abutment surface moves in the longitudinal direction of the path.
Nereby, wear of the inside of the path will not be concentrated at a
restricted area, as would be the case if the spiral had been radiahly
rigid. A spiral supported by a central mechanical shaft entails such
a "concentrated" year if the spiral abuts against the path in its end
regions.
An infeed device 40, shown in Fig. 1 as a hopper-like device,
connects to an opening 11 provided in the path, the infeed opening of
the path. In the longitudinal direction of the path the infeed
opening 11 is of a length which essentially corresponds to the entire
length of the spiral 30. The spiral and the path form, in this
region, a feed compartment 35 for the supplied material. In one
preferred embodiment, the diameter a.nd pitch of the spiral are then
adapted such that the spiral has substantially but one spiral turn.
Between the infeed opening 11 of thr path and the discharge opening
12 of the apparatus, there is disposed a chamber 41 surrounded by a
casing 42 in the circumferential direction. That part of the space
which is located between the free end 39 of the spiral and the
discharge opening 12 of the path forms a space which,
WO 93/09936 PCT/SE92/00802
2~pp6~3_ 6
hereinafter, will generally be designated the compaction cell of the
apparatus. The compaction cell normally consists of a part of the
chamber 41, but in certain embodiments a part of the feed compartment
35 is also included in the compaction cell. U!ith the exception of the
dimensions, the cross-sectional configuration of the compaction cell
is optional. It may, for example be circular, oval, include curved
portions, be polygonal etc.
The free end 39 of the spiral is disposed in the region of the
transition 36 between the opening 11 and the compaction cell 15. The
intention here, in certain embodiments" is to project the spiral a
short distance into the chamber 41, at most approximately half of the
length of the chamber and, as a rule, at most approximately one third
of the length of the chamber. In another emhodinrent, the free end 39
of the spiral is located in the region of a plane transversely of the
axial direction of the spiral path the bounding definition of the
infeed opening 11, most proximal the discharge opening 12, in a third
embodiment, the spiral terminates ahead of the above-mentioned plane
and at a distance therefrom corresponding to at most one third of a
thread pitch, as a rule at most a quarter of a thread pitch.
The chamber" 41 surrounded by the casing <<2 is dimensioned so as to
eliminate the risk of jamming of material v;hich is fed into the
chamber. This is achieved in that the chamber 42 is given larger
cross-section than the feed compartment 35. Primarily the upper
bounding definition 4v of the chamber is raised in relation to the
corresponding part of the feed compartment. As a rule, the side
definitions 44a,b and lower definition 45 of the chamber are also
placed at a greater distance from a geometric centre line 31
continuing from the spiral 30 than corresponding parts of the feed
compartment in relation to the centre line. To this end, in certain
embodiments the transition between the feed compartment and the
chamber forms a step, while in other embodiments the transition
diverges continually. There are also embodiments in urhich the step is
substantially replaced by the chamber 41 continually flaring tovrards
the discharge opening 12 of the chamber (the apparatus). Elowever, in
this latter case, the upper bounding definition of the chamber is, as
a rule, raised in comparison with the corresponding portion of the
~ WO 93/09936 PCT/SE92/00802
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feed compartment. In certain embodiments, the chamber is provided
with substantially continually tapering cross-sectional area after
the step.
In connection with the discharge opening 12 of the casing there is
disposed a baffle member l3a,b which prevents displacement of the
material. The baffle members are designed to assume a position ~:~hich
does not prevent displacment of the material on a pressure loading
which exceeds a certain value. In Fig. 1 examples of alternative
embodiments of the baffle member are shov:n in which these are
journalled in the outer edge of the opening 12.
In the lower region of Fig. 1, there is shown a baffle member 13a
which is connected to the opening '12 of the compaction cell 15 in a
journal 17, This 1S designed as a hinge with a built-in return
spring, i.e. a spring which returns the baffle member to its starting
position when the baffle member is not under the influence of
external forces. The hinge is provided with means for adjusting the
size of that force with which the integral spring of the hinc_te acts
on the baffle member.
In the upper portion of the Figure there is shown an embodiment in
which a baffle member 13b is journalled in a journal 1G, The baffle
member is provided with one or more projecting portions 20 which, via
one or more spring members 1°, hold the baffle member in the position
illustrated in the Figure. Ey modifying the distance between the
journal 16 and the anchorage point of the spring member 18 in each
respective projecting portion 20, that force which is required for
moving aside the baffle member 13b from the starting position of the
member is regulated. It will be obvious to a person skilled in the
art that the baffle can be of any optional design and also be
connected to any optional suitable, fixed portion of the apparatus.
Similarly, means are provided in certain embodiments for
pretensioning the spring members
Two embodiments for returning the baffle members and for governing
the force required for moving the baffle members in a direction away
from the starting position of these members have been describes above
WO 93/09936 PCT/SE92/00802
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and shovrn on the Drawings. It will be obvious to the skilled reader
that a corresponding function will also be achieved in other
embodiments, for example employing pneumatically or hydraulically
operating devices. It ~o~ill likewise be obvious to a person skilled in
the art that the positions of the journals 16 and 17 for the baffle
members are selected in certain embodiments so that the journals are
disposed within the compaction cell 15. In such instance, the baffle
members are at least partly disposed within the path 10. In certain
embodiments, the baffle members are designed as resiliently returning
throttle cones.
At least one first mechanical guide member 50 is disposed
substantially above the spiral 30 and in the region of the opening
11. The guide member is oriented in the longitudinal direction of the
spiral and is of a length which substantially corresponds to the
length of the infeed opening in the longitudinal direction of the
spiral. It further applies according t:o the invention that the guide
member is disposed on the support side of the path, i.e. on that side
against which the spiral blade 33 is displaced in a radial direction
on rotation of the spiral. The disclosed displacement in a radial
direction depends upon the direction of rotation (right or left-hand
turn; of the spiral and those reaction forces which occur bet:~:een the
spiral and the material displaced by i:he spiral. The guide member 50
is located closely adjacent or abuts against the outer defining edge
32 of the spiral, at least when the spiral 30 rotates. The guide
member also forms a scraper blade for material which accompanies the
spiral on its rotation, In addition, i~he guide member prevents the
spiral from being lifted up out of thE~ path as a result of upvrardly
directed forces which may occur on roi~ation of the spiral. In one
preferred embodiment in which the apparatus includes one or more
first guide members 50, the minimum distance between the first guide
member and the opposing wall 28a of the opening is generally less
than the diameter of the spiral, also in this embodiment, it is
ensured that the spiral remains in its path if the spiral were to be
exposed to upwardly directed forces. .As a rule, the first guide
member 50 constitutes a sufficient obstacle preventing the spiral
from being lifted up out of its path.
WO 93/09936 PCT/SE92/00802
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In certain embodiments, at least one supF ementary mechanical ouide
member 51 (,second guide member) is provided in the region of the
opening 11. The supplementary guide member is disposed on the
opposite side of the opening 11 in relation to the previously
mentioned (first) guide member. Generally, the second guide menber is
also of a length corresponding to the length of the first guide
member and is oriented in the longitudinal direction of the spiral.
The distance betvreen the first guide member 50 and the second guide
member 51 is less than the diameter of the spiral. It will hereby be
ensured that the spiral is not lifted up out of its path as a result
of possible up~.vardly directed forces. which may occur in connection
with rotation of the spiral.
In one preferred embodiment in which the apparatus is intended to
compact moist material and, in such instance, reduce the moisture
content in the material, the path 1C and/or the casing 42 is proviaed
vrith drainage apertures 14 through vuhich liquid pressed out of the
material leaves the feed compartment 35 and/or the compaction cell
15. As a rule, drainage means 14, such as perforations, apertures
etc, are provided in both the feed compartment and the compaction
cell.
Fig. 1 also sho~~rs one embodiment of the present invention in which
the compaction cell 15 accommodating the feed compartment 35 and the
chamber 41 consists of ttvo separate parts tvhich are interconnected by
means of connection devices 19 and 21, respectively. These are shown
in the Figure as flange elements, but it will be obvious to a person
skilled in the art that any appropriate oesign whatever of the
connection devices may be employed without departing from the spirit
and scope of the present invention.
In certain embodiments, the chamber ~'~1 is connected to a container
(not shown), in which event the compaction cell is, in certain
practical applications, connected to the container in the region of
the discharge opening of the compaction cell while, in othe r
practical applications, the compaction cell is wholly or partly
housed in the container.
WO 93/09936 PGT/SE92/00802
~~,~p06~3 to -
The design of the feed compartment 35 and the compaction chamber 15
as two separate units also affords considerable freedom in the
dimensioning of the feed compartment and cornpaction cell in
dependence upon the relevant composition of the material which is to
be handled by the apparatus. Thus, it applies that the length of the
compaction cell is selected, for instance, depending upon the desired
degree of compaction and/or total solids of the material once it has
passed through the apparatus, or requisite friction to achieve a
stable material plug in the compaction cell. The other dimensions
involved may also be adapted in response to the relevant material
type. Thus, the compaction cell is preferably given greater height
and width than the feed compartment in the event of massive material
pieces. Both the feed compartment 35 and the compaction cell 15 are
given cross-sectional configuration which is adapted to suite the
relevant material type. Likewise, the clearence betareen the path and
the spiral is dimensioned in view of the material which is to he
handled.
Figs. 4-6 show one embodiment of the present invention in urhich tyro
mutually cooperating spirals 30a,b are provided for infeed of
material to the compaction cell 15a. l:n this embodiment the apparatus
is substantially constructed corresponding to that previously
described vrith particular reference to Figs. 1-3. For the sake of
simplicity, the same reference numerals vrill be employed for the
embodiment illustrated in Fig. 4 as those previously used for devices
corresponding to previously described devices. The path 10 for each
respective spiral is of a design corresponding to that disclosed
above for previously described embodiments, entailing that, in those
areas where the spiral normally abuts against the path 1G or, in
certain operational cases is brought into abutment against the path,
the minimum radius of curvature of the path corresponds substantially
to or exceeds half of the outer diameter of each respective spiral.
Even though the expression radius of curvature has been employed
here, the described principle is also applicable when only portions
of the path forr~ supports which are discrete in the longitudinal
direction. Urive means 60 impart to the spirals counter-directed
rotation (cf, the arro~t~s A), the direction of rotation being selected
so that the material, on displacement towards
WO 93/09936 ~ 3 PCT/SE92/00802
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the compaction call 15a, will also :;how a tendency to be disple.ced
tovrards the region between the tyro spirals. Hereby, material is
accumulated in a central material >trand which forces the spirals
downwardly and assists in preventing the spirals from being raised up
from the path 10a.
The Figures show one embodiment of the compaction cell 15 which is
suited for use when the apparatus iincludes tyro mutually cooperating
spirals 30. In such instance, the c;ompaction cell 15 has, in the
illustrated embodiment, a substantially planar upper bounding
definition 46 and a substantially planar lo~~rer definition 45. The
upper definition merges in the lov~rErr definition via bounding
definitions 44a,b which, in their lover regions curve in tovrards the
substantially planar lower definition 45.
In one preferred embodiment, the guiding of the rotation of the
spirals is designed such that rotation is terminated by each
respective spiral being set in a reception position in ~:rhich that
portion of the spiral blade vrhich is located beneath the central
region of the infeed opening is located adjacent the lowermost part
of each respective path. This disclosure also applies to embodirlents
comprising but a single spiral.
hihen the apparatus according to the present invention is reduced into
practice, material is suppliec! via the infeed device 4G and the
infeed opening 11. The drive means 60 rotate the spiral 3G and this
displaces material tovrards the discharge opening 12 of the casinG.
The baffle members 13 arrest the material in its displacement and a
material plug of compacted material begins to be built up in the
compaction cell 15,15x. i~iew material which is fed in b; the spiral is
accumulated and compacted against the material plug and, when this
has reached a certain length, it exercises such a pressure against
the baffle members that these give vvay. However, movement of the
material plug in the casing is still retarded by the friction betn~een
the casing, the baffle members and 'the material in the plug, at the
same time as the spiral blade, at its free end, forces material
towards the plug and thereby compacts the material. As nevi material
is fed through the opening, material is accumulated and compacted
WO 93/09936 PCT/SE92/00802
21Q4~~'~3 - ~2 - m..
against the plug and this is displaced out of the casing. Gn
compaction of the material, extremely high compacting forces are
achieved since the material is located in a restricted and small
space and since the compressive forces applied against the material
are concentrated to a very small surface area whose size is
determined by the end portion of the spiral.
On rotation of the spiral, the guide member 50 (which closely
approaches the spiral proper) prevents material from penetrating in
between the spiral and the path. On rotation of the spiral, material
may occasionally adhere to the spiral blade but the guide member
scrapes such material free from the spiral blade,
compaction apparatus according to the present invention v;ill be of
considerably smaller dimensions and display a higher degree of
compaction than a screw: compactor of corresponding capacit;,~, since
the screvr compactor has a "flow area" for the material which is
determined by the height of the thread blade, vrhile the spiral
compactor has a "floe area" which i<.> substantially determined by the
diameter of the spiral. An increase in the transport area in the
compaction cell 15 in relation to the feed compartment 35 will
eliminate the clog risk which occurs in prior art spiral compactors.
The compact construction makes it possible to install the spiral
conveyor in areas vrhere available space does not permit installation
of spiral compactors according to prior art technology for the
material vrhich passes into the compaction cell.
The above detailed description has referred to but a limited number
of embodiments of the present invention, but it will readily be
perceived by a person skilled in this art that the present invention
encompasses a large number of embodiments vrithout departing from the
spirit and scope of the appended claims.
