Note: Descriptions are shown in the official language in which they were submitted.
7~
LEAKPROOF ENDLESS BELT CONVEYOR
Background of the Present Invent_on
This application relates to endless belt conveyors of
the type in which the upper and lower fli~ht of an endless
belt extend around and between a front end drive roll and a
rear end return roll. Such types of endless belt conveyors
are used to convey material from one point of an industrial
or manufacturing facility to another, sometimes directly,
and sometimes by utilizing a plurality of such conveyors in
sequence in which material is deposited onto one end (feed
10 end) of a conveyor and delivered to the other or discharge
end from whence it is discharged onto another conveyor which
may be running in an opposite direction or in the same
direction. Such conveyors may be positioned on the floor
and easily accessible, or they may be positioned up near the
15 ceiling of such manufacturing or industrial facilities to
provide more operating space therebelow. Sometimes such
conveyors are used to carry discrete items of a large size
thereon, in which case the features of the present invention
are not as relevant. In other cases, however, such con-
20 veyors are used to carry particulate material such astobacco, fibers, grain, sand, and the like thereon. Endless
belt conveyors may include a flat belt, they may have side
walls with slanted selvage strips therealong to provide a
trough for the material, or the bed of the conveyor itself
25 and the belt may be curved to provide more of a trough-like
effect. It is in conjunction with all of these types of
conveyors, which carry particulate material, that the pre-
sent invention is concerned.
In such conveyors for carrying particulate material,
30 several problems may occur. First, depending ùpon the par-
ticulate material, considerable amounts thereof may be lost
during the conveying in various ways. First of all,
material may be lost at the transfer point from one con-
veyor to another by the material either being spilled off
the sides at the transfer point, or becoming airborne as
would be the case in very small powdery~ e material, such
as fibers, or tobacco. Material is also lost at the
discharge end of a conveyor where the belt conveyor bends
around the drive roll, and the curve that has been built
into the conveyor must return to a flat configuration. At
this point, it is difficult to constrain the material within
the confines of the belt and it is sometimes lost over the
10 edges of the belt as it progresses around the discharge
pulleys or rollers~ A significant area where partiulate
material is lost is across the lateral edges of the upper
~light of the belt conveyor if there are no side walls there-
on. Generally this can be corrected to some extent by pro-
15 viding si~e walls. Material is also lost that clings to thebelt conveyor as it becomes the lower flight returning
beneath the upper flight. Often the material that clings to
the belt will become deposited either on the floor beneath
the conveyor, or on some type of dust pan therebeneath which
20 must be periodically emptied. ~inally, material is also
lost as the belt moves around the rear or return end of the
conveyor. Here in cases in which there is a dust pan
beneath the lower flight, there will be some type of cleat
or wiper attached to the conveyor at spaced points to wipe
25 the pan clean and bring it back around the return end of the
conveyor to the upper flight. In such cases at the rear
end, material is often lost off the edges of the return
bight of the conveyor.
A separate problem which occurs, other than lost
30 material, is the problem damage causes by particulate
material which works its way between the flights of the belt
conveyor, between the conveyor and its support pans, or bet-
ween the conveyor and the return rollers. Such material
~z~
builds up, becomes deposited in the rollers, and eventually
will cause damage unless the convey~r is periodically
stopped, torn down by a machinist and either cleaned or
repaired. This obviously results in expensive down time and
maintenanceO
Summa_y of the Present Invention
The present invention, on the other hand, is directed to
a solution for the above problems which is accomplished by
providing an effective edge seal for the belt conveyor, not
10 only along the upper flight thereof, but along the lower
flight, and around the drive roll and return roll. In addi-
tion, the conveyor of the present invention is provided with
a cover or hood to prevent loss of material which becomes
a;rborne. By providing the cover, not onl~ can material be
15 maintained within prescribed confines, but since there is an
enclosed atmosphere, that atmosphere can be treated by the
introduction of moisture or like to provide a humidity
control, which may be very important in the processing of
some particulate materials such as tobacco and textile
20 fibers.
There are four basic areas of the conveyor with which to
be concerned: 1) the side edges of the upper fligh~ of the
belt conveyor; 2) the side edges of the lower flight of the
belt conveyor; 3) the side edges of the belt conveyor as it
25 moves around the return end of the roller; and 4) the side
edges of the belt conveyor as it moves around the discharge
end roller. In the broadest sense, seals for these ~reas
may be effected to some extent merely by providing a sealing
block that is formed appropriately and positioned on the
30 side walls of the framework of the conveyor at such points
as to provide a friction type engagement of the side edges
of the belt all the way around its circumference. This is a
viable approach within the scope of the present invention;
however, there are certain further advantages which may be
35achieved by utili~ing other features of the conveyor whîch
~2~7~
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are present.
For example, air slide conveyoxs have become available
more i~ recent years. ~ir slide conveyors offer the advan-
tage that the normal friction which occurs between the con-
veyor belt and its support pan is minimized. As a result,less energy is used in driving the belt, and less wear is
realized on the belt with the result that less maintenance
is required. By incorporating the seal concept of the pre-
sent invention in an air slide conveyor, the air which
10 impinges against the underneath side of the belt may be uti-
li~ed to help form the side and end seals in the following
manner. As air impinges on the underneath side of the belt,
it liEts the side edges of the belt into engagement with
side sealing blocks to effect the side seal discussed
15 hereinabove. The air is then channelled off the sides,
collected into a longitudinal channel, and conducted to the
discharge end roller where it i5 allowed to discharge
inwardly toward the axial center of the conveyor belt. This
discharged air blows the particulate material back toward
20 the center of the belt and prevents escape of the material
through the sides thereof. The slight pressure of the side
edges of the belt against the side sealing blocks along the
longitudinal extent of the upper flight thereby provides
sufficient seal to prevent inadvertent discharge of ~he par-
25 ticulate material off the sides of the helt, and yet doesnot cause undue wear or drag on the belt. Also, rather than
pressing sealing blocks against the lower flight, the lower
flight of the belt is allowed to drop by gravity onto the
sealing blocks to provide a slight pressure thereaginst,
30 which is sufficient to prevent inadvertent loss of material
across the side edges of the belt as it returns underneath
the conveyor.
.. .
7~
One or more cleats are provided on the endless belt to
continuously wipe the dust pan beneath the conveyor, thereby
preventing buildup of fine dust thereunder. As the belt
then returns over the return roll, a return roll cap includes
a sealing block which provides slight pressure against the
edge of the belt conveyor to prevent loss of material
thereunder.
It is therefore an object of the present invention to
provide an improved endless belt conveyor which prevents
10 leakage of particulate matter across the edges thereof.
Another object of the present invention to pr~vide an
improved endless belt conveyor of the type described in
which the leakage is prevented by sealing the side edges
completely around the circumference of the belt conveyor.
Yet another object of the present invention is to pro--
vide a leakproof endless belt conveyor which utilizes an
existing supply of air on the convey~r to effect the seal
alony the upper flight side edges and drive roll side edges.
Other objects and a fuller understanding of the inven-
20 tion will become apparent from reading the followingdetailed description of a preferred embodiment along with
the accompanying drawings in which:
Figure 1 is a perspective view looking at the discharge
end of the endless belt conveyor according to the present
25 invention;
Figure 2 is a sectional view taken substantially along
lines 2-2 in Figure l;
Figure 3 is an enlarged perspective ~iew, with parts
broken away, illustrating a portion of the discharge end of
30 the conveyor;
Figure 3a is a perspective view illustrating the inside
of a discharge end cap removed from the conveyor;
Figure 4 is a perspective view, with parts broken away,
illustrating the rear or feed end of the conveyor according
3~ to the present invention;
47~
Figure 5 is a perspective view illustrating the rear end
cap removed from the conveyor of the present invention; and
Figure 6 is a perspective view of one support pan sec-
tion illustrating the top, end, and one side.
Detailed Description of a Preferred Embodiment
Turning now to Figure 1, there is best illustrated an
ovexall view of the endless belt conveyor 10 of the present
invention which is supported on any type of conventional
type of framework 12. The conveyor apparatus 10 includes an
10 endless belt conveyor 14 having a rear or feed end 16 and
discharge end 18. Particulate material is fed from a hopper
or from the discharge end of a preceding conveyor through a
feed chute 20 onto the feed end 16 of conveyor 14. It
should be pointed out that in some cases the feed chute 20
15 may be eliminated and the particulate matter be fed directly
from the discharge end of one conveyor (not shown) onto the
feed portion of a subsequent conveyor.
A fan 22 is mounted in any convenient location and
includes a hose 24 and input nozzle 26 for directing a posi-
20 tive flow of air into the interior of the conveyor apparatus10 as will be described hereinafter. A drive motor 28 is
mounted on a suitable support bracket 29 above the discharge
end 18 of the conveyor apparatus for supplying the drive
force necessary to turn drive roll 38. In this regard out-
25 put shaft 30 from drive motor 28 includes an upper pulley 32attached to the end thereof, and a drive chain 34 connects
the upper pulley 32 with the lower pulley 36. In turn, the
lower pulley is secured to the end of drive roll 38, whereby
operation of the drive motor causes the drive roll to rotate
3ncarrying the endless belt 14 in its conveying path. A
plurality of cover ~ections 40 extend across the upper edges
of the side walls of the conveyor apparatus and attach to
cover brackets 42. The covers are preferably of a
transparent plexiglas material, substantially flat, however,
35are bent into the domed shape illustrated in Figure 1.
7~
Turning now to Figure 2, there is illustrated a cross-
sectional view of the conveyor apparatus 10. A pair of side
walls 44,46 extend in sections longitudinally of the length
of the conveyor apparatus 10. A dust pan 48 connects the
lower edyes of side walls 44,46 and catch any particulate
material which falls from the lower flight 74 of the endless
belt 14. A support pan 50 extends between side walls 44,46
at a point approximately intermediate the height thereof.
Support pan 50 includes a perforated upper panel 52, a lower
panel 54, side panels 56,58 and end walls 60. The support
pan 50 is formed in a plurality of sections approximately
ten feet in length. Further, each section is assembled by
means of brackets 80, which are positioned at each end of
each pan section. The brackets from one pan thus abut the
adjacent brackets from the other pan, and bolts (not shown)
extend through openings 81 in the bracket to secure the pans
together. Each end wall 60 of the pans 50 include a plura-
lity of openings 62 therein, so that when the pans are
assembled, there is a continuous air communications from one
end of the conveyor to the other through the pan. The pan
construction can be further seen in Figure 6. Each opening
60 includes a rubber or polymeric grommet 65 (Figure 6~
therearound, so that when two adjacent pans are abutted, the
grommets of one pan engage the grommets of another and pro-
25 vide a seal to pxevent leakage of air therearound.
A selvage strip 63 extends along the inner surface ofside walls 44,46 longitudinally thereof. The selvage strip
63 is triangular shaped and includes an angled member 64 and
a horizontal member 66. Angled member 64 is secured to the
3 side wall 44,46 at a point near the upper edge thereof and
extends inwardly and downwardly therefrom to a point 65
which is spaced above support pan 50. The hori~ontal member
66 extends from the termination point- 65 of angle mem~er 64
horizontally outwardly toward the side wall and is connected
3~ thereto. A sealing block 70 is attached to the undersurface
~2~47~
of horizontal member 66, however, terminates at a point 71
spaced from side walls 44,46 for reasons to be hereinafter
described.
In the arrangement illustrated in Figure 2, the upper
5 flight 72 of the endless belt 14 then lies between the
sealing block 70 and the upper panel 52 of support pan 50.
The lateral edges of upper flight 72 extend to a point
approximately one inch from the side walls 44,46. In the
normal position with no air introduced through inlet nozzle
1026, the upper flight 72 rests on the upper panel 52 of the
support pan 50. However, when the fan 22 is activated upon
activation of the motor 28, and air is introduced into the
interior of support pan 50 through no~zle 26~ the air,
passing through perforations 76 causes the upper flight 72
5to lift into sealing engagement with sealing block 70.
Obviously, there must be a side opening in one of the pan
sections 50 and through side wall 46 to allow introduction
of air thereinto. Otherwise, the remaining support pan sec-
tions do not need side openings, because once the air is
20introduced into one of the support pans, it is communicated
with the other support pans through the openings 62.
The air that impinges against and lifts the upper flight
72 of the endless belt, moves outwardly into the longitudi-
nal channel 78 which extends lengthwise of the conveyor
25apparatus and is formed by the outer edge of sealing block
70, the upper panel 52 of support pan 50, the inner surface
of walls 44,46, and the under surface of the horizontal
member 66 of selvage strip 63. The purpose of this air con-
duit will be discussed hereinafter.
The lower sealing blocks 68 extend longitudinally of the
conveyor apparatus 10 alongside side walls 44,46, and are
attached to and rest on dust pan 48. The lateral edges of
lower flight 74 then rest upon sealing blocks 68 as the
lower flight returns beneath the conveyor. As the lower
35flight 74 returns, one or more cleats 73 attached to the
surface of the endless belt 14 wipe the pan 48 clean.
4~7~
Obviously, the height of cleat 73 must be at lea5t equal to
or greater than the distance between lower flight 74 and
dust pan 4% in order to obtain the required wiping action.
The sealing action at the discharge end is best
5 illustrated in Figures 3 ar,d 3a. ~oward this end, there is
provided an end cap 82 which basically extends the seal
around the end of the discharge roller to seal the lateral
edges o the endless belt 14 as it circumnagivates the end
rollers. Cap 82 includes an arcuate shaped metal cover 84
which is attached to the adjacent side ~all 44,46 or to the
selvage strip 63 in any conventional manner. Inside the
metal cover 84 is an arcuate shaped sealing block 86 having
the same outer radius of curvature as that of the metal
cover 84. Looking at Figure 3a, it can be seen that block
1586 is not as wide as metal cover 84, and therefore there is
a channel 88 remaining between the block 86 and side wall
44. The sealing block 86 is also arcuate shaped, so that
when assembled, channel 88 is actually an extension of the
longitudinal channel 78 illustrated in Figure 2. Thus, when
20the air is introduced through noz~le 26 into the support
pans $0, as it flows into channel 78, the air will flow down
into channel 88~ The inner curvature of sealing block 86 is
such that there is a slight gap 90 between sealing block 86
and the return bight of the discharge end 18 of the endless
25belt 14. Thus, there will be a flow of air through the gap
90 which will tend to force any particulate material near
the edge of belt 14 back toward the central axis thereof.
This air flow thus acts as an air seal to keep particulate
material from working its way through the slot 90 at the
30discharqe end of the conveyor.
Turning now to the rear end 16 of the conveyor apparatus
10, there i5 illustrated in Figures 4 and 5 the sealing
means for preventing particulate matter from escaping from
the endless belt 14 at that point. In this regard, a shield
3592 encircles the endless belt 14 as it moves around the rear
end roller. As can be seen in Figure 5 a generally U-shaped
2 ~7~
--10--
sealing block 94 is attached to the inner surface of shield
92, and whe~ assembled, provides a slight frictional engage-
ment with the lateral edges of belt 14. This effectively
forms a seal and maintains the particulate material on the
belt 19 as it moves around the rear or feed end of the con-
veyor apparatus. The sealing block 94 has a pair of legs
96,98 which engage correspondingly shaped portions of
sealing blocks 68 and 70 of the rear end conveyor section.
The air from channel 78 which flows ~earwardly of the con-
10 veyor merely escapes this point~to prevent a buildup of air.While a gravitational type air seal has been shown, it is
obvious that an air seal could be provided for the lower
flight also by expanding the width of support pan 50 and
providing perforatlons in the lower panel thereof. Air
15 would then impinge against the lower flight and force it
against sealing blocks 68.
Looking now at Figure 6, there is illustrated a portion
of one of the support pans which better illustrates the per-
Eorations 76 in the upper surface thereof and the openings
20 62 in the end walls with the grommets 65 therearound. It
should be pointed out here that should the openings 62 not
be sufficient to provide a good flow of air longitudinally
of the conveyor, the openin~s 62 can be replaced with a
larger slot or plurality of slots.
Finally, should the particulate material being processed
need a controlled atmosphere, such as humidity control, this
can be easily accomplished by introducing the air with the
proper moisture content through nozzle 26 to the support
pans 50. The only difference in the construction of the
30conveyor 10 would be that when the air is introduced into
side channels 78, there are perforations in the horizontal
member 6~ and angular member 64 of the selvage strip which
allows CQmmUnication for the humidified air to be introduced
into the conveying chamber which extends between side walls
While a preferred embodiment of the invention has been
described in detail hereinabove, it is obvious that various
changes and modi~iciations might be made without departing
from the scope of the invention which is set forth in the
accompanying claims.
