U.S. patent number RE29,386 [Application Number 05/684,190] was granted by the patent office on 1977-09-06 for gravity discharge apparatus.
This patent grant is currently assigned to Alfred L. Miksitz. Invention is credited to Frank J. Miksitz.
United States Patent |
RE29,386 |
Miksitz |
September 6, 1977 |
Gravity discharge apparatus
Abstract
Granular material is fed downwardly in a stream of controlled
rate from a bin or the like by means of a horizontal apertured
plate moving in a horizontal orbital path beneath a fixed shroud
which is disposed within the mass of material in the bin.
Inventors: |
Miksitz; Frank J.
(Phillipsburg, NJ) |
Assignee: |
Miksitz; Alfred L. (Bethlehem,
PA)
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Family
ID: |
27042101 |
Appl.
No.: |
05/684,190 |
Filed: |
May 7, 1976 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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216105 |
Jan 7, 1972 |
3809286 |
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Reissue of: |
467558 |
May 6, 1974 |
03874566 |
Apr 1, 1975 |
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Current U.S.
Class: |
222/404 |
Current CPC
Class: |
B65G
65/4863 (20130101) |
Current International
Class: |
B65G
65/00 (20060101); B65G 65/48 (20060101); B65D
083/06 () |
Field of
Search: |
;222/404,409,410,411
;214/17D ;259/37 ;34/168 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Reeves; Robert B.
Assistant Examiner: Shannon; John P.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Parent Case Text
RELATED APPLICATION
This is a continuation-in-part of prior application Ser. No.
216,105, filed Jan. 7, 1972, now U.S. Pat. No. 3,809,286, the
subject matter of which is incorporated herein by reference.
Claims
What is claimed is:
1. Apparatus for passing granular material from a first zone to a
lower second zone with the assistance of gravity comprising: a
shroud; an apertured feed plate disposed in a horizontal plane
below said shroud.Iadd., a horizontal shelf plate below said feed
plate, said shelf plate having a discharge aperture of lesser area
than the aperture in said feed plate so that a portion of the upper
surface of said shelf plate is exposed within the aperture in said
feed plate.Iaddend.; and drive means for moving said feed plate in
a horizontal orbital path, the relationships among the horizontal
dimensions of said shroud and of said feed plate and the radius of
said orbital path being such that during orbital movement of said
feed plate at least a portion of the peripheral upper surface of
said plate extends horizontally beyond the lower end of said
shroud.
2. Apparatus as in claim 1 wherein said feed plate includes an
upwardly projecting annular dam surrounding the aperture in said
feed plate.
3. Apparatus as in claim 1 wherein the lower surface of said feed
plate is provided with downwardly extending stud-like elements.
.[.4. Apparatus as in claim 1 including a horizontal shelf plate
below said feed plate, said shelf plate having an aperture of
greater area than the area of the aperture in said feed plate..].
.[.5. Apparatus as in claim 1 including a horizontal shelf plate
below said feed plate, said shelf plate having an aperture of
lesser area than the area of the aperture in said feed
plate..]. 6. Apparatus for passing granular material from a first
zone to a lower second zone with the assistance of gravity
comprising: a shroud; a feed plate having a feed aperture disposed
in a horizontal plane below said shroud; a horizontal shelf plate
below said feed plate, said shelf plate having a discharge aperture
of lesser area than said feed aperture so that a portion of the
upper surface of said shelf plate is exposed within said feed
aperture; and drive means for moving said feed plate in a
horizontal orbital path. 7. Apparatus as in claim 6 wherein said
feed plate includes an upwardly projecting annular dam surrounding
the aperture
in said feed plate. 8. Apparatus as in claim 6 wherein the lower
surface of said feed plate is provided with downwardly extending
stud-like
elements. 9. Apparatus for passing granular material from a first
zone to a lower zone with the assistance of gravity comprising: a
shroud; a feed plate having a feed aperture disposed in a
horizontal plane below said shroud, said feed plate including an
upwardly projecting annular dam surrounding said feed aperture; and
drive means for moving said feed plate in a horizontal orbital
path. .Iadd. 10. Apparatus for conveying granular material by
gravity assist from a mass thereof supported on a horizontal wall
provided with a discharge aperture, said apparatus comprising: a
shroud disposed above the discharge aperture with at least the
lower end of the shroud being disposed within the mass of material;
a feed plate disposed between said shroud and said discharge
aperture, said feed plate being of smaller horizontal dimensions
than said horizontal wall and having at least one vertically facing
feed aperture in register with the discharge aperture, said feed
aperture being of greater area than said discharge aperture so that
a portion of the upper surface of said horizontal wall is exposed
within said feed aperture; and means for orbiting said feed plate
about a vertical axis in a manner such that the feed aperture
remains in register with the discharge aperture and such that a
peripheral portion of the feed plate will slide under a quantity of
material and then carry at least a portion of that quantity
inwardly toward said feed aperture whereby material continuously
flows inwardly to said aperture along a path which moves around the
periphery of said aperture and whereby the material is then pushed
over the edge of the discharge aperture in the form of a continuous
stream. .Iaddend..Iadd. 11. Apparatus as in claim 10 wherein the
horizontal dimension of said feed plate is less than the horizontal
dimension of said shroud. .Iaddend..Iadd. 12. Apparatus as in claim
10 wherein the horizontal dimension of said feed plate is greater
than the horizontal dimension of said shroud. .Iaddend..Iadd. 13.
Apparatus as in claim 10 wherein said feed plate includes an
upwardly projecting annular dam surrounding the feed aperture.
.Iaddend..Iadd. 14. Apparatus as in claim 10 wherein the lower
surface of the feed plate carries downwardly projecting stud-like
elements which slidably engage said horizontal wall. .Iaddend.
Description
This invention relates to methods and apparatus for effecting
gravity assisted flow of granular material and, in particular, to
methods and apparatus for the controlled feed of granular material
from an upper zone into a lower zone.
The prior application discloses an apparatus in which the feeding
or discharging of granular material from a mass thereof is effected
and closely controlled by a special arrangement of a centrally
apertured horizontal feed plate disposed below a fixed shroud or
baffle located within the mass of material. The disposition of the
shroud is such that the granular material does not flow
spontaneously by gravity through the apertured feed plate when the
latter is stationary. However, the granular material does flow
spontaneously to an extent into the periphery of the space directly
below the shroud where it comes to rest in the form of an annular
mass of material of which at least a portion resides on the upper
surface of the plate. Thereafter, the plate is driven in an orbital
path about a vertical axis with the result that granular material
on the plate is carried inwardly with respect to the vertical axis
of the shroud. As this occurs an additional quantity of material
flows by gravity from the main mass into the space formerly
occupied by the displaced quantity thereby preventing reverse
displacement of the initially displaced quantity during continued
orbital movement. Rather, the feed plate moves relative to the
initially displaced material so that an edge portion of the
aperture in the plate moves under this material which then passes
through the aperture by gravity. The overall result is that
granular material is continuously fed downwardly through the feed
plate along a path which moves in a circle, the flow of material
being proportional to the speed of the plate.
SUMMARY OF THE INVENTION
It has been found that under some circumstances it is necessary for
the feed plate in an apparatus of the kind described above to reach
out beyond the periphery of the shroud in order for it to perform a
proper feeding or discharging operation. This may be necessary, for
example, if the granular material has little or no tendency to flow
inwardly under the shroud. This condition may be present if the
material is finely-divided and non-free-flowing as may be the case
with especially cohesive or sticky substances. The condition may
also result if the material contains lumps which are of large size
relative to the vertical distance between the shroud and the feed
plate. For example, some powders which are readily free-flowing
once they are put in motion tend to form arches within the mass of
powder when a portion of the material is removed by gravity through
a feed or discharge aperture with the result that flow through the
aperture will be intermittent or cease altogether. In the case of
chunky material containing lumps of irregular size and shape, the
material may wedge between the shroud and the feed plate and impede
or prevent flow of the material.
Another aspect of the present invention is the provision of a
ring-shaped feed plate having a central hole which is larger than a
feed hole in a horizontal shelf or wall over which the feed plate
is mounted. In this construction, orbital movement of the feed
plate displaces the granular material inwardly toward its center in
the manner described above but instead of falling by gravity
through the hole in the feed plate the material is first deposited
on the shelf and is subsequently pushed over the edge of the feed
hole in the latter by continued orbital movement of the feed plate.
This arrangement permits a smaller area of contact between the
lower surface of the feed plate and the shelf and thereby reduces
friction at this location. The same is true with respect to reduced
friction between the upper surface of the feed plate and the mass
of granular material. In addition, the feed plate tends to remain
buried by the granular material, and this is advantageous in
protecting the feed plate from any corrosive atmosphere which may
be present. This type of feed plate may have a diameter either
greater or smaller than the shroud.
It is a further feature of the invention to provide a shrouded
orbital feed plate type of apparatus adapted to feed granular
material, such as an aerated powder, which would normally be so
free-flowing as to pass under the shroud and though the feed
aperture even without movement of the plate. This may be
accomplished by providing the upper surface of the feed plate with
an inclined annular dam which projects upwardly toward the shroud a
distance sufficient to prevent free flow of the granular material
when the plate is not moving. The feed plate may have a diameter
larger or smaller than the shroud.
It is a further feature of the invention to provide a special
purpose granular material feeding device which does not require the
presence of a shroud above an apertured orbital feed plate. This
type of apparatus is suitable for feeding granular material which
has such a strong tendency to form an arch above an aperture that
it will not flow spontaneously through the aperture. Orbital
movement of the feed plate continuously breaks the arch and permits
gravity flow of the material.
Throughout this description orbital movement of a feed plate means
that the plate moves in generally a circular path either with or
without rotation about its own axis. When there is no rotation of
the plate about its own axis, all points on the plate move in
circular paths of the same radius which is small compared to the
radius of the plate. When the plate also rotates about its own
axis, the plate moves generally as if its circumference were
rolling along the inside of a ring of slightly greater diameter
than the plate. These are the same movements disclosed in the
aforesaid application Ser. No. 216,105. It is immaterial to the
invention what form of drive means is employed to effect either
form of movement.
By granular material is meant any solid or semi-solid material in
the form of discrete particles, grains or lumps without regard to
size or density so long as the material can be made to flow
downwardly by gravity when acted on by the feed plate. The term
encompasses all types of finely divided material including ground
cement, as well as larger particulate matter, such as sand, stone
and coal.
DETAILED DESCRIPTION OF EMBODIMENTS
The invention will be further understood from the following more
detailed description taken with the drawings in which:
FIG. 1 is a vertical sectional view of a feed apparatus embodying
an orbital feed plate which extends beyond its shroud and which has
a feed aperture of greater diameter than the discharge aperture in
the bottom of the apparatus;
FIGS. 2 and 3 are sectional views taken on the lines 2--2 and 3--3,
respectively, of FIG. 1;
FIG. 4 is a vertical sectional view of a feed apparatus embodying
an orbital feed plate which extends beyond its shroud and which has
a feed aperture of lesser diameter than the discharge aperture in
the bottom of the appartus;
FIG. 5 is a vertical sectional view of a feed apparatus embodying
an orbital and rolling feed plate which remains within its shroud
and which has a feed aperture of greater diameter than the
discharge aperture of the apparatus;
FIG. 6 is a vertical sectional view of a feed apparatus embodying a
double concentric orbital and rolling feed plate similar to that
shown in FIG. 5;
FIG. 7 is a vertical sectional view of a feed apparatus embodying a
double concentric orbital feed plate;
FIG. 8 is a vertical sectional view of a feed apparatus embodying a
special-purpose feed plate which includes an inclined annular dam
on its upper surface; and
FIGS. 9 and 10 are vertical sectional views of feed apparatus
embodying special-purpose orbital or rolling feed plates which
operate without shrouds.
Referring to FIGS. 1, 2 and 3, there is shown a feed apparatus 10
located in the lower tapered end of a bin, silo or other vessel,
defined by inclined side walls 12 and a horizontal shelf 14 or
bottom wall, the latter including a circular discharge aperture 16.
The feed apparatus 10 includes a generally frustoconical shroud 18
which is supported by a plurality of legs 20 in a position above
and axially aligned with the aperture 16. A generally circular feed
plate 22 of greater diameter than the shroud 18 is slidably
supported on the bottom wall 14 below the shroud 18. The periphery
of the feed plate 22 is notched as shown at 24 to receive the legs
20 which support the shroud 18.
The feed plate 22 is driven with the aforesaid orbital movement by
any suitable means such as an electric motor 26 supported by the
shroud 18 in a position such that the motor shaft 28 is coaxial
with the discharge aperture 16. A horizontal crank arm 30 is fixed
to the motor shaft 28 and carries at its outer end a fixed
depending stub shaft 32 which is parallel to the motor shaft 28.
The shaft 32 fits into a bearing 34 which is disposed coaxially
above a centrally located circular feed aperture 36 in the feed
plate 22. The bearing 34 is fixed with respect to the feed plate by
legs 38 which are rigidly connected to the upper surface of the
feed plate 22 and to the casing of the bearing.
To reduce friction between the upper surface of the feed plate 22
and the granular material and between the lower surface of the
plate 22 and the shelf 14, the plate 22 may be slotted as shown at
40 to reduce the area of contact. However, since the feeding
function of the plate 22 depends on friction between the plate 22
and the granular material, the design of the plate 22 will vary
with the type of material being handled. In some instances, it may
be desirable to increase friction by providing a plurality of small
upwardly directed cleats or the like (not shown) on the upper
surface of the plate 22 near the periphery thereof. To reduce the
power required to drive the plate 22 into the granular material the
outwardly facing edges of the plate 22 and of the slots 40 should
be chamfered as shown at 42 and 44, respectively. However, the
inwardly facing edges of the feed aperture 16 and the slots 40
should be vertical to aid in gripping the granular material. The
peripheral edge of the plate 22 may be smoothly circular, as shown,
or it may be uneven as by the provision of horizontal toothlike
projections.
The lower surface of the feed plate 22 may be flat or as
illustrated in FIGS. 1 and 3, it may be provided with a plurality
of short stud-like elements 46 which engage the shelf 14 and
thereby support the plate 22 slightly above the shelf 14. The
illustrated construction is effective in preventing the build-up or
pulverized material between the plate 22 and the shelf 14. It has
been found, for example, that in feeding coal the finer particles
tend to accumulate under the plate 22 and force it upwardly with
resulting misalignment and damage to the elements of the drive
system, if the stud-like elements or their equivalent are not
present.
In operation of the apparatus of FIGS. 1, 2 and 3, the crank arm 30
which is fixed to the motor shaft 28 is driven by the latter at a
low rpm to impart orbital movement of the feed plate 22 through the
interaction of the off-set stud shaft 32 on the bearing 34.
Frictional forces on the feed plate 22 tend to cause the latter to
roll or rotate about its own axis, that is, the axis of the bearing
34. However, this rotation is prevented by engagement of the walls
of the notches 24 with the legs 20. The orbital movement causes a
peripheral portion of the feed plate 22 to reach out into the
granular material beyond the shroud 18 and to then move inwardly to
drag granular material to a position under the shroud 18. The
material may tend to form an arch from the base of the shroud to
the bottom of the bin, but the feed plate 22 breaks the heel of the
arch. This differs from the conditions present when a feed plate
always remains wholly under its shroud, because in the latter case
the granular material is relatively unconsolidated for the reason
that it has flowed by gravity into the form of an annular mass
disposed under the shroud. The extended form of feed plate 22 also
performs the very important function of breaking the heel of any
arch which might form in the granular material as a result of the
non-free-flowing characteristics of the latter. As pointed out
previously, some granular materials which are free-flowing when
agitated are sufficiently cohesive that they tend to form an arch
extending across an aperture through which they are flowing by
gravity. The arch can, of course, be broken by mechanical agitation
of the material, and this is the effect of the feed plate 22 as it
penetrates into the material. During continued orbital movement of
the feed plate 22 the granular material which has been dragged
under the shroud 18 moves across the upper surface of the feed
plate 22, is deposited on the shelf 14 and is then pushed over the
edge of the discharge aperture 16 in the latter in the form of a
continuous stream. The locus of the path of the falling material
continuously moves around the periphery of the aperture 16, as
described previously. The mass rate of flow through the aperture
for a given set of conditions varies only with the speed of the
feed plate 22.
If the discharge aperture 16 in the shelf 14 were larger than the
feed aperture 36 in the feed plate 22, the granular material would
be fed continuously through the aperture 36 in a path moving around
the periphery of the latter. In the illustrated embodiment, the
feed plate 22 has been designed purposely with a relatively large
feed aperture 36 in order to reduce friction by reducing the
distance which the granular material must move across the feed
plate 22. The smaller annular area of the feed plate 22 will
normally be covered with the granular material and this is
beneficial in shielding the feed plate 22 from any high temperature
or corrosive atmosphere which may be present.
FIG. 4 illustrates a feed apparatus 10 which includes a circular
orbital feed plate 22 having a larger diameter than its shroud 18
and having a feed aperture 36 of smaller diameter than the
discharge aperture 16 in the shelf 14 of the bin. The other
elements (not shown) and the operation are the same as previously
described with respect to FIGS. 1, 2 and 3, except that the
granular material falls directly through the feed aperture 36
rather than first being deposited on the shelf.
FIG. 5 illustrates a feed apparatus 10 which includes a circular
orbital and rolling feed plate 22 having a smaller diameter than
its shroud and having a feed aperture 36 of greater diameter than
the discharge aperture 16 in the shelf 14. The feed plate is free
to rotate about its own axis during orbital movement. The other
elements (not shown) and its operation are as described above.
FIG. 6 illustrates a feed apparatus 10 which includes a two-part
orbital and rolling feed plate 22 similar in structure and
operation to that shown in FIG. 5. The feed plate 22 includes an
annular outer part 22a and a concentric annular inner part 22b
constructed with common legs 38 so that the parts 22a and 22b move
together. The shelf 14 is stepped as shown at 14a and the lower
central circular portion thereof is provided with the discharge
aperture 16. The diameter of the feed aperture 36a in the outer
plate part 22a is greater than the diameter of th stepped-down
portion of the shelf 14, and the diameter of the feed aperture 36b
in the inner plate part 22b is greater than the diameter of the
discharge aperture 16. In operation of the device, granular
material passes over the plate part 22a onto the upper portion of
the shelf 14, is pushed over the step 14a onto the lower portion of
the shelf, passes over the lower plate part 22b to be again
deposited on the lower portion of the shelf 14, and is then pushed
over the edge of the discharge aperture 16.
FIG. 7 illustrates a feed apparatus 10 which includes a two-part
orbital feed plate embodying some of the features of FIGS. 1 and 6.
The outer feed plate part 22a is of greater diameter than the
shroud 18, while the outer features of the apparatus are as shown
in FIG. 6.
FIG. 8 illustrates a feed apparatus 10 which is especially adapted
for feeding granulated or powdered material into, for example, a
pneumatic conveyor conduit. In this embodiment, the shroud 18 is
shown as being supported from above by suitable brace members 48
attached to the side walls 12 of the bin. In feeding a pneumatic
conveyor conduit the material which spontaneously flows inwardly
under the shroud may become aerated or partially fluidized by
adventitious pressure fluctuations in the system; in such instance
the aerated material might flow through the discharge aperture 16
at irregular or uncontrolled rates if not prevented from doing so.
The feed plate 22 is constructed with an annular dam 52 which
surrounds the feed aperture 36 and which is inclined downwardly and
radially outwardly as shown. The upper edge of the dam 52 is above
the lower edge of the shroud and thereby blocks the spontaneous or
uncontrolled flow of powdered material into the feed aperture 36.
In some cases the dam may extend upwardly to a point below the
lower edge of the shroud. In either case, upon orbital movement of
the feed plate 22, the material will be urged over the dam 52 so as
to pass through the apertures 36 and 16 into a pneumatic conveyor
conduit 54 through which a stream of air is passing in a leftward
direction.
The conveying air passing the point of discharge can cause a
lowered pressure at that point due to a siphoning effect of the
high velocity air stream. This may cause pressure disturbances near
the feed plate 22 with resultant fluidization of the material. To
equalize pressure and prevent such pressure disturbances a conduit
can connect the region under the shroud to the pneumatic conveying
line in order to maintain the pressures about equal at these two
locations. Such a pressure-equalization conduit should be
constructed essentially vertically thereby avoiding horizontal
sections where granular material may tend to build up. As shown, a
conduit 50 leads from the upstream portion of the conveyor conduit
54 into the area just below the upper end of the shroud. A second
conduit 51 terminates in the top of the bin. A secondary benefit of
the conduits 50 and 51 is momentary aeration caused by pressure
fluctuations which would promote flow and minimize the possibility
of hang-up of material.
In many cases in which the present invention is used to feed
cohesive or non-free-flowing material it may often be desirable to
include in the bin or hopper aeration nozzles or jets to inject air
or other gas into the mass of material, thereby rendering it free
flowing; this may also be accomplished by causing the bin or
hopper, or even the shroud of the feeder, to vibrate at a suitable
frequency. Such gas injection or vibration may cause the material
to flow through the discharge aperture 16 at irregular and
uncontrolled rates. In such instances an annular dam 52 as shown in
FIG. 8 on feed plate 22 may be incorporated into any of the devices
of FIGS. 1 through 8 to block the spontaneous or uncontrolled flow
of granular or powdered material into the feed aperture 36 or the
discharge aperture 16.
In the FIG. 8 embodiment the drive system is located below the feed
plate 22. The bearing 34 is disposed centrally within the feed
aperture 36 and is connected to the feed plate 22 by a suitable
spider 56. The drive shaft 28 is supported by bearings 57 within a
sleeve 59.
FIGS. 9 and 10 illustrate special-purpose feed apparatus in which
orbital or rolling feed plates 22 operate withou the use of
shrouds. In this embodiment the granular material is so cohesive as
to be essentially nonflowable because of the formation of an arch
58 above the discharge aperture 16. Orbital movement of the feed
plate 22 breaks the heel of the arch and permits the material to
flow through the feed aperture 36 and the discharge aperture 16. In
FIG. 9 the feed aperture 36 has a lesser diameter than the
discharge aperture 16, and in FIG. 10 it has a greater diameter.
The drive system for the plates 22 may include sequentially
operated hydraulic cylinders 60, the piston rods 62 of which engage
the periphery of the respective plate 22.
* * * * *