U.S. patent number 3,874,641 [Application Number 05/388,592] was granted by the patent office on 1975-04-01 for agitator assembly for a discharge hopper.
Invention is credited to Peter J. Tolan.
United States Patent |
3,874,641 |
Tolan |
April 1, 1975 |
AGITATOR ASSEMBLY FOR A DISCHARGE HOPPER
Abstract
An agitator assembly for use with a discharge hopper, in which a
pair of agitator members are suspended from a movable support
member so as to be positioned adjacent opposite hopper wall
portions, said movable support member being attached to a fixed
support member by a pair of pneumatic bellows disposed at opposite
ends thereof, and control means is provided for actuating said
bellows alternately, whereby said agitator members are raised and
lowered alternately.
Inventors: |
Tolan; Peter J. (Scituate,
MA) |
Family
ID: |
23534738 |
Appl.
No.: |
05/388,592 |
Filed: |
August 15, 1973 |
Current U.S.
Class: |
222/200 |
Current CPC
Class: |
B01F
15/0298 (20130101); B01F 15/0235 (20130101) |
Current International
Class: |
B01F
15/02 (20060101); B01f 011/00 () |
Field of
Search: |
;222/196,200,243-248,334
;259/DIG.43,4,37,47,112-114 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tollberg; Stanley H.
Assistant Examiner: Stack, Jr.; Norman L.
Attorney, Agent or Firm: Ross; Robert E.
Claims
I claim:
1. An agitating device for use with a discharge hopper of the type
having side walls and a discharge opening, said device comprising a
support and an agitator member secured to the support by a pair of
spaced fluid extensible means, and means for actuating said fluid
extensible means alternately.
2. An agitating device for use with a discharge hopper of the type
having side walls and a discharge opening, said device comprising a
support and at least one agitator member depending from the
support, said support comprising a fixed portion and a movable
portion connected by a pair of spaced pneumatic extensible means,
and means for actuating said pneumatically extensible means
alternately so that a rocking motion is imparted to the movable
portion of the support.
3. An agitator device for use with a discharge hopper of the type
having inclined walls leading to a discharge opening, said device
comprising a fixed support member dimensioned to span the hopper
and be supported thereby, a movable support disposed above the
fixed support and connected thereto by a pair of fluid extensible
bellows, a pair of agitator members depending from the movable
support, and means for alternately actuating said bellows to cause
them to extend and retract alternately.
4. A discharge hopper, comprising a hopper body having side walls
leading to a discharge opening and at least one agitator plate
disposed in said hopper, and means for oscillating said plate in
said hopper, said means comprising fluid actuated extensible means
connected between the agitator plate and a fixed member.
5. A discharge hopper as set out in claim 4 in which a pair of
agitator plates are provided in the hopper in spaced relation to
each other above the discharge opening, and a pneumatic bellows is
associated with each plate, and means is provided for actuating
said bellows alternately.
6. A discharge hopper as set out in claim 5 in which said plates
are suspended from opposite ends of a movable support bar, and said
pneumatic bellows are connected between the fixed member and
opposite ends of said support bar.
Description
BACKGROUND OF THE INVENTION
In the feeding of powdered, granular, flake, or the like material
from a supply hopper onto a conveyor or into containers, a common
problem is "bridging" of the material in the hopper, whereby a
self-supporting arch of the material forms between the opposite
walls of the hopper. Many devices have been utilized for preventing
or correcting such bridging, such as means for vibrating the hopper
walls, pulsating devices, internal mechanical agitators, all of
which have disadvantages. Most of the devices used heretofore for
this purpose must be built as an integral part of the hopper when
the hopper is originally constructed. Devices of the vibrating
type, which may be attached to the outside wall of an existing
hopper, are not effective with large hoppers because of the large
mass involved, and are not effective at all with certain types of
material such as wood chips. Mechanical agitating devices have had
the disadvantage of high original cost and of requiring
considerable maintenance expense due to the fact that the moving
parts of the device, such as bearings, are covered or
intermittently exposed to the material being fed. When agitating
devices must be repaired, the hopper and any upstream or downstream
equipment is out of operation.
SUMMARY OF THE INVENTION
This invention relates to an agitator assembly for use with a feed
hopper of the type described, which may be readily assembled with
an existing hopper and which may be readily assembled for repair or
removal and replacement of the agitator members. The assembly
comprises a fixed support for attachment to an existing hopper,
which support may span the hopper at an upper portion, and a
movable support member attached to the fixed support by a pair of
pneumatic bellows, one bellows being disposed at each end of the
movable support. Depending from each end of the movable support is
an agitator member which may be of any shape best suited for the
type of material being fed by the hopper. The agitator members may
be positioned to lie parallel to opposite wall portions in spaced
relation thereto. Means is provided for actuating said bellows,
that is, to cause them to extend and contract, alternately, so that
the agitator members are alternately moved by the resulting rocking
motion of the movable support member, to destroy any bridging of
material in the hopper. In a preferred form of the invention, the
movable support is supported only by the bellows, so that there are
no bearings, pivots, or the like to wear or become jammed by the
material in the hopper.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view, partly broken away, of a discharge
hopper having agitator means embodying the features of the
invention;
FIG. 2 is a view in section of the hopper assembly of FIG. 1, with
the actuating bellows in the unpressurized condition;
FIG. 3 is a view in section taken on line 3--3 of FIG. 2;
FIG. 4 is a view similar to FIG. 2 showing the movement of the
agitator member during operation of the device, the full line
showing the position thereof when one bellows is energized, the
dashed line showing the position of the agitator when the other
bellows is energized;
FIG. 5 is a schematic view of an electricial and pneumatic control
circuit for controlling the operation of the agitator mechanism of
FIGS. 1-4.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Referring to the drawing, there is illustrated a feed hopper 10
which comprises inclined side walls 12 leading to a discharge
opening 14 for transferring material from a storage hopper 16 to a
conveyor 18 for further processing or packaging.
Disposed within the hopper is an agitator assembly 20 which
comprises a fixed member 22 spanning the hopper and a movable
member 24 attached to the fixed member by a pair of expansible
bellows 26 and 28. The movable member 22 comprises an upper portion
30 which carries pneumatic fittings 32 to supply air to the bellows
and a lower portion 34 suspended from the upper portion and
disposed below the fixed member. Suspended from opposite ends of
the lower portion 34 is a pair of agitator members 36 which, in the
illustrated embodiment, are in the form of grids disposed in spaced
relation to and parallel to the adjacent side walls of the hopper
when the agitator is in the at rest position. In the illustrated
embodiment the side walls of the hopper taper in size from the
width of the supply hopper at the top to the width of the discharge
opening at the bottom. The agitator members have a corresponding
taper, however they are narrower than the corresponding dimension
of the side wall.
Referring to FIG. 4, there is illustrated an electricial and
pneumatic control circuit for the agitator, which comprises a
four-way valve V operated by solenoid S. Power to the solenoid is
supplied from any suitable power source P through a timer T, which
may be adjusted to control the rate at which the solenoid S is
energized and de-energized. When the solenoid is energized, the
four-way valve is moved to admit air from a suitable air supply A
to one of the bellows, and when the solenoid is de-energized, the
four-way valve returns to its other position to admit air to the
other bellows and to release the pressure from the first bellows.
Quick exhaust valves Q may be provided at the bellows, so that the
air in the bellows need not return to the four-way valve to
exhaust, but may exhaust directly from the bellows to obtain faster
release of air.
The motion imparted to the movable member 24 by the alternate
bellows action is a rocking motion. As one bellows is pressurized
and extended, the other bellows is being exhausted and retracted,
and serves as a pivot about which the member 24 moves. The
agitators therefore move between the full line position and the
dashed line position of FIG. 3, whereby one agitator moves
downwardly and away from the adjacent wall and the other moves
upwardly and toward its adjacent wall, with the bottom end of the
grids moving back and forth over the discharge opening 14.
This oscillatory motion of the agitators prevents any bridging of
the material in the hopper, and insures a continuous flow of
material out of the discharge opening. The use of pneumatic bellows
allows considerable force to be applied to the material in the
hopper, such as may be required to agitate wet, heavy, or lumpy
material. With an air supply of 80 psi and a bellows diameter of 6
inches, a force of about 2,000 pounds can be applied to the
agitator member, however such high force does not result unless it
is required by the resistance to movement met by the agitator.
The rate of cycling of the agitator depends on the material being
fed, but is generally relatively slow. For example, in feeding of
wood chips, a cycle rate of 1-15 cycles per second may be used.
Although in the illustrated embodiment, a pair of bellows is
provided, in some installations it may be possible to provide a
single bellows at one end of a movable member with a pivot at the
other end. For certain types of material, it may also be desirable
to support the movable member centrally from the fixed member by a
pivot.
Although the use of pneumatic bellows in the manner illustrated is
advantageous, due to the lack of pivots, bearings, or other
mechanical devices, the motion imparted by the alternately
energized pair of bellows can be substantially achieved by
mechanical means or by pneumatic or hydraulic pistons.
One of the advantages of the agitator means disclosed herein is the
fact that it may be added to an existing feed hopper without major
structural modification. The agitator assembly must, of course, be
dimensioned to fit the particular hopper into which it is to be
assembled. Another advantage of the disclosed agitator assembly is
the fact that the agitators may be readily removed from the hopper
for repair, or for transfer to another hopper of similar size.
Another advantage of the illustrated structure is the fact that the
fixed member and movable member, in extending across the hopper
above the opening helps to support the column of material in the
hopper, so that the weight thereof does not rest on the conveyor
belt, which would tend to interfere with the operation of auxiliary
vibratory equipment at the conveyor, by damping out the vibrations
and rendering the equipment ineffective.
Since certain other changes may be made in the illustrated
embodiment without departing from the scope of the invention, it is
intended that all matter contained herein be interpreted in an
illustrative and not a limiting sense.
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