Note: Descriptions are shown in the official language in which they were submitted.
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CONVEYOR
The present invention relates to a conveyor suitable for
use in conveying bulk material and especially to such
conveyors capable of elevating such material.
Most commonly bulk material which requires to be elevated
at a more or less steep angle of rise, is conveyed in
bucket conveyors. Such conveyors have various disadvant-
ages though including cost and relative complexity of
construc~ion, noisy operation, spreading of dust, etc.,
inconvenient loading due to the need to load individual
buckets, and difficulty of clearing of the individual
buckets which is further aggravated by the tendency for
material to adhere to and be retained in such buckets.
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More recently there have been proposed so called cover belt
conveyors, in which two belts are inter-engaged along a
conveying path so as to seal the bulk material being
carried within a confined space defined between the belts.
In one conveyor of this type, there is provided a first
carrier belt and a second closure belt both of which are
generall~ "U"-shaped with corrugated sides. The carrier
belt further has a plurality of regularly spaced
upstanding plates which divide the carrier belt interior
into a plurality of individual compartments. With this
type of conveyor, however, the loading arrangements
possible are relatively restricted and cumbersome. In
2~ addition there is a substantial tendency or the bulk
material, especially those types which are somewhat
sticky or not particularly free flowing, to become lodged
in the corrugations and/or in the corners between the
upstanding plates and the base of the carrier belt. ~n
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addition these same fea~ures are particularly awkward
and difficult to clean thereby resulting in significant
additional operating costs. In the meantime, it will
further be appreciated, that the effective conveying
capacity of the conveyor will be reduced by an amount
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corresponding to the volume of material trapped in the
conveyor.
It is an object of the present invention to avoid or
minimise one of more of the above disadvantages.
The present invention provides a conveyor suitable for use
in conveying bulk material which conveyor comprises an
endless carrier belt and an endless bulk material engage-
ment means^
characterised in that said bulk material engagement means
comprises elongate flexlble connector means mounting a
plurality of spaced apart paddles, said carrier belt and
endless connector means being mounted for movement along
a conveying path with said paddles projecting substantially
into the interior of a channel defined by said carrier belt
at least alony said conveying path, in close proximity to
the sides and base of said channel so as to engage bulk
material within said channel in use of the conveyor and
transfer drive forces between said connector means and
said bulk material during uphill or downhill conveying
of said bulk material, said paddles having a shape, at
least at their distal ends, corresponding generally to
the cross-sectional shape of said channel, and with said
connector means and said belt following a substantially
identical path in a vertical plane along the con~eying
path where said belt and engagement means interengage,
whereby movement of said paddles and said belt therealong
is maintained in substantial synchronism.
It will of course be appreciated that the belt and
bulk material engagement means are normally only required
to move together Iwith the paddles projecting into the
channel) along inclined conveying paths so that where
the conveyor is desired to include a generally horizontal
conveying path section, the carrier belt may extend
beyond the endless connector means, the latter being
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guided towards and away from the carrier belt at/or
proximity to end portions of the inclined conveying path
section.
Thus with a conveyor of the present invention uphill and
downhill conveying of bulk material can be effected
substantially without relative movement between the
paddles and carrier belt in a direction along the
- conveyiny path thereby avoiding wearing of these parts
and/or damage thereto resulting from such relative
movement. In addition such an arrangement allo~s a wide
variety of materials to be conveyed over steep inclines
with varying or intermittent feed rates. Thus friable
materials can be readlly handled with little or no
degradation and wet, sticky, frozen, irregular shaped,
andtor a~rasive material can be carried wlth minimal
accummulation on the conveyor and/or damage thereto.
The bulk material may moreover range in size from fines
to relatively large lumps e.g. 0.6m size on a 2m wide belt.
Also with a conveyor of the present invention it is
possible substantiaIly to fill the carrier belt with
bulk material thereby allowing a high load capacity to
be achieved for a given size of conveyor, and quite
steeply inclined, e.g. 70 or more to the horizontal,
conveying paths to be safely negotiated which in turn
can result in substantial economies in the length of
conveyor required and its construction, allow increased
flexibility in the routing of the conveying path and
reducing site area requirements for the conveyor thereby
minimising the site area sterilised by conveyors. .At
the same time the conveyor of the present invention
permits easy and flexible loading arrangements and
minimises cleaning requirements as well as facilitating
such cleaning as may be required. The endless carrier
belt and bulk material engagement means will generally
be disposed in a back-to-back arrangement, being guided
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towards and away from each other at the beginning and
end of said conveying path. Thus by effectively and,
along their respective return pathways, actually
separating, at least a substantial part of the material
engagement component from the carrier component of the
conveyor, the problems of material lodging and being ;
retained between the two are further minimised. Moreover ~`-
since the carrier belt itself is merely required to
support and carry the material without being required to
provide any special additional function it can be made
of quite plain construction e.g. a deformable flat belt,
which ls not only more economical than other mo~e complex
forms of carrler but also mlnimises the problem of
material lodging in it and is easy to clean.
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The conveyor of the invention may be used with various
forms of drive arrangement including driving of the
endless ~onnector means only and d iving o~ both the
elevator and the carrier belt. In the former case, the
carrier belt will be carried along indirectly by the
friction between the bulk material engaged by the paddles
and the carrier belt, or by direct engagement of the
paddle edges with the carrier belt. Such arrangements
are generally preferred since they avoid the need for
using a relatively highly tensioned carrier belt,
thereby allowing more economical belt constructions to
be employed and/or providing increased belt life, lower
replacement costs, and cheaper repairs by means of
mechanical jointing instead of vulcanizing. Indeed the
carrier belt components may be substantially identical
to those used in conventional horizontal channel belt
conveyors thereby simpllfying design work and increasing
reliability through the use of standard proven components.
It will also be appreciated that the use of low tension
belt systems significantly reduces the risk of belt
breakage and conveyor down-time resulting therefrom.
Any suitable form of flexible connector means may be
us d in the conveyor of the invention including for
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example, chains and cables. Conveniently two such
connector elements are used, disposed at either side of
the channel form carrier belt.
Preferably the engagement means paddles are generally
curved so as to define together with the channel defined
by the carrier belt a generally scoop shaped receptacle,
each said paddle forming a generally upright generally
transverse wall curving round at opposite sides in a
directior. up the inclined conveying path. Generally
said oppGsite sides of the paddle means progressively
reduce in depth in said direction. Advantageously the
paddle means havç generally transversely outwardly
- projecting mountlng wings formed and arranged so as to
extend over and down alongside the side walls of the
channel formed by the carrier belt, for securing o~ the
paddles to respective endless connector elements.
With such paddles the angle of inclination of the
conveying path and/or the carrying capacity of the
conveyor may be maximised without however the risk of
significant accumulation and sticking of the bulk
material on the carrier belt or bulk material engagement
means.
The conveyor of the invention also allows a wide range
of feed arrangements to be used including side loading,
loading on inclined or horizontal belt runs, and loading
at intermediate levels, thereby avoiding the need for
transfer points and tandem conveyors.
If desired the paddles may be further provided with
resiliently deformable edge seals, at their carrier-belt
co-operating periphery, to minimise escape of bulk
material therebetween and to maximise drive transmission
therebetween. Also they may be provided with deformable
or deflectable central portions at their upper edges
remote from said carrier belt engaging periphery, so
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that in the event of larger pieces of material becoming
lodged between the driving and return runs of the
elevator, these portions can give way and ride over the
piece to avoid jamming of the elevator and/or possible
damage to conveyor. The portions may be of flexible
material'such as rubber secured in the principal plane
of the paddle or may be in the form of sm~ll rigid
inset panels hingedly mounted and retained in the principal
plane of the paddle by suitable spring means.
In general the paddles are disposed so as to project
generally at right angles from their direction of
travel along the conveying path but advantageously they
may be formed and mounted on the elevator drive trans-
mission member so as to be inclined rearwardly with
respect to an uphill direction along the conveying
path. With such an arrangement with effective fill
capacity of the individual compartments defined by the
paddles within the carrier belt in a rising conveyor of
invention may be significantly increased. In addition
discharg~ from such a conveyor is facilltated and any
tendency of the bulk material to adhere to the paddles
as they are separated away from the carrier belt, reduced.
As noted above, the elongate connector means could be in
the form of a belt and this will help further to contain
the bulk material within the conveyor. In the case of
a chain or cable connector means there may be provided,
if desired, a cover plate means above the bulk material
engagement means along the conveying path in order to
minimise escape of dust etc.
For the avoidance of doubt, it should be noted that
the present invention extends to conveyors with both
horizontal and rising sections in which elevator means
are provided only at the rising sections of the carrier
belt, as well as to conveyor installations such as
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horizontal bunker conveyors and moving bed chain
conveyors in which the carrier belt extends only substant-
ially horizontally, short horizontally extending lengths of
the bulk material engagement means being provided to
boost driving of the horizontal carrier belt with the
bulk material thereon, by engagement of the paddles with
the bulk material or belt.
Any suitable arrangement known in the art for routeing
of the return segments of the carrier belt and elevator
may be used. In general the elevator will most
conveniently be returned above the carrier belt with the
carrier belt and elevator in a back-to-back arrangement.
Alternatively though, the return segment of the elevator
could be routed around the carrier belt below the return
lS run of the carrier belt.
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Various suitable forms of loading arrangements may be
employed with conveyors of the present invention
including end loading, side loading, and top loading
which may in turn be directly "through" the elevator
the material being allowed to fall through elther side
of the paddles into the carrier belt either through
both forward and return runs of the elevator or, more
commonly through the forward, conveying, run only of
the elevator as or just after it is brought into the
"V" or "U"-shaped channel defined by the carrier belt,
the return run being routed sufficiently far away from
the conveying path at that point to allow introduction
of material therebetween. In another possible arrangement
there is provided a short conduit encasing the elevator
immediately upstream of the beginning of the conveying
path and extending along part of the return path of
the elevator to permit top loading into the upstream
end of the conduit, the material then being carried round
the conduit by the elevatox into the "U"-shaped channel
defined by the carrier belt. In the case of end loading
the material is loaded onto part of the carrier belt
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extending horizontally upstream of a position at which
the elevator is brought fully together with the carrier
belt.
Further preferred features and advantages of the invention
5 will appear from the following detailed description given
by way of example of some preferred embodiments illustrated
with reference to the accompanying drawings in which:
Fig. 1 is a side elevation of a conveyor of the invention;
Figs. 2 to 4 are detailed views of a paddle of the
lO conveyor of Fig. 1 shown on an enlarged scale and in which:
Fig. 2 is a side elevation;
Fig. 3 is an end elevation; and
Fig. 4 is a plan view; and
Fig. 5 is a schematic side view of another conveyor
installation o the invention ~or use in downhill conveying.
Fig. l shows a conveyor l suitable for use ln uphill
conveying bulk particula1:e material 2. The conveyor 1
comprises a carrier belt 3 and a bulk material engagement
means 4. The carrier belt 3 extends around return pulleys
S and over guide rollers 6 (See Fig. 3) formed and arranged
so as to define a flat-bottomed generally "V"-shaped
channel 7 along the conveying path of the conveyor l.
The bulk material engagement means 4 comprises a flexible
endless connector means member in the form of two chains
8 mounting 9 a plurality of spaced apart upstanding paddles
in the form of generally arcuate plates 10 (See Fig. 4)
corresponding generally to the cross-sectional shape of
the channel 7 defined by the carrier belt 3 and guide
rollers 6 ~see Fig. 3). As may be seen in more detail in
30 Figs. 2 to 4 the arcuate plates lO have a central generally
upright wall portion 11 (inclined slightly forward in the
conveying direction) extending tranversely of the carrier
belt and cl~rving round at either side into side walls 12
of reducing depth extending generally in the uphill
35 direction of the conveyor 1, so that the paddle plates lO
form, together with the carrier belt, generally scoop-
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shaped receptacles 13 for holding and increasing uphillpropulsion of the bulk material 2 by reducing escape
thereof from the carrier belt 7 during uphill conveying.
In addition the outer circumferential edge 14 of each
.~ 5 plate 10 is provided with a seal element 15 for engagement
with the carrier belt 3 further to minimise escape of
material 2. The use of such curved shaped plates 10 also
has the further advantage of maximising the strength of the
paddles and their impact resistance as well as heIping to
centralise the bulk material 2 in the carrier belt 3
thereby improving belt tracking. At either side of the
arcuate plates 10 are provided outwardly projecting wings
~ lOa which are formed so as to rise up over the inclined
- sides 3a of the troughed carrier belt before depending
downwa~d].y to the chain mountings 9 at a level generally
alongside the lower edge lla o the central portion 11 o~
the padd].e plate 10.
As shown in Fig. 1 the bulk material engagement means
4 extends around return guides above the conveying path
which are in the form of. sprockets 16, at least one of
which can be used for driving or braking thereo~ during
uphill or downhill conveying, respectively.
The chains 8 may be supported between the return sprockets
16 on suitable support sprockets or rollers 17 as shown
under the return run. Conveniently though in their
conveying run the chains 8 are supported substantially
solely through the paddles 10 resting on the carrier
belt 3 thereby also maximising frictional engagement
therewith and hence drive transmission thereto or therefrom.
The carrier belt 3 is returned 5 below the conveying path
the belt 3 being supported in the form o a shallow flat
bottomed "V"-shaped channel 7 along the return path on
the guide rollers 6. It will be appreciate~ that with a
substantially plain belt configuration as shown there
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will be :Little danger o material 2 lodging in or adherincJ
to the belt and any cleaning that may be required can be
readily effected.
The bulk material engagement means 4 and carrier belt 3
are mounted on a generally conventioned form of structural
framework support 18 (as shown schematically in Fig. 5),
the conveyor 1 being provided adjacent its lower end l9
with a loading chute 20 and at its upper end 21 a discharge
hopper 22 disposed for receiving material 2 discharged
from the conveyor 1.
Fig. 5 shows a modified conveyor arrangement 23 wherein
the conveying path is generally 'S'-shaped with the
interengcaging runs 24, 25 of the carrier belt 3 and
material engagement means 4, respectively, having concave
and convex portions 26, 27 at the lower and upper end
portions 28, 29, respectively, of the conveying path.
The carrier belt 3 has, moreover, ex~ended horizontal
sections where assistance from the paddles is not required,
continuir.g beyond the upper and lower ends 30, 31 of
the bulk material engagement means 4. Thus this embodiment
also illustrates how uphill or, as in this particuIar case
as indicated by the arrows 32, downhill conveying can be
effectively integrated into extended distance conveying
between different levels, without the need for a number
of separate conveyors and complex transfer arrangements
therebetween.
In use of the conveyor 1 for uphill conveying, the bulk
material engagement means 4 is driven with its paddles
10 projecting into the channel 7 defined by the carrier
belt 3 in frictional engagement with the carrier belt 3
so as to entrain particulate material 2 within said
channel 7 at ~he same time pulling along the carrier belt
3. In this way a separate friction drive for the carrier
belt 3 may be dispensed with and drive efficiency
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maximised by use of a positive drive connection through
a suitable sprocket engaging with the chain 8. Moreover
by routeing the chains 8 o, the bulk material engagement
means 4 generally in register with the base 30 of the
- 5 trough 7 defined by the carrier belt 3 along the main
part of the conveying path along which the material
engagement means 4 interengages the belt 3, in the vertical
plan i.e. with the same radius of curvature in the vertical
plane (see Fig. 1), relative movement and slipping between
the paddles 10 and the belt 3 is substantially avoided
thereby avoiding wearing and damage thereto. It will also
be appreciated that the plate edges 14, 15 of the paddles
10 will engage the carrier belt 3 particularly posi~ivel~
at sections of the conveying path which are curved in the
vertical plane (upper end 21 in Fig. 1 and upper and lower
ends 26, 27 in Fig. 5) so that drive transmission there-
between will be particularly eEfective at those sections.
Whilst this will generally be more important for uphill
conveying (Fig. 1) it is also desirable in downhill
conveying (Fig. 5).
Also as may be seen from Fig. 1 the paddles 10 may be
disposed at a relatively close spacing along the chains
8 thereby further maximising the effective material
conveying capacity of the conveyor which is already quite
favourable due to the shape of the paddles used.
As further shown in FigO l the carrier belt 3 flattens
out as it approaches the return pulleys 5, the belt guide
rollers 5 being suitably configured thereat. Where,
as in the Fig. 5 embodiment, the conveyor includes
extended horizontal carrier belt runs 35, it will be
appreciated that the carrier belt 3 may have a more
flattened configuration than in the inclined run sections.
It will also be appreciated in relation to the choice of
connector means for the bulk material engagement means
that where chains are used it is possible to use multiple
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drive sprocket arrangements at intermediate arrangements
thereby avoiding the need for very large drive systems
at the conveyor ends and high tension in the connector
means to transmit drive along the full length of the
connector means.
Conveniently the paddles 10 are provided with deflectable
and/or resiliently deformable panels 33 at their central
upper edges 34.
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