GB2084968A - Discharging hoppers - Google Patents

Abstract

Apparatus adapted to form the bottom of a storage hopper comprises a large upper activator section 12 and a smaller lower activator section 14. Each activator section includes a baffle member 60 or 66 therein and an electro-mechanical gyrator 38 or 52 is attached to each section to vibrate each section in a plane normal to the hopper axis to promote a positive flow of material from the storage hopper. The gyrator 38 attached to the upper activator section is operated intermittently and the two sections are vibrationally isolated from each other to segregate the vibrational forces in each section. <IMAGE>

Description

SPECIFICATION Double gyrator compound bin activator This invention relates to improvements in bin activator apparatus adapted to form the bottom of a storage hopper, or bin, to promote a positive flow of material therefrom.

Conventional storage bins have large crosssections which converge to small outlets at the bottom. Most flow problems are caused by materials wedging and compacting into the converging part of the bin. When the bins are full, the enormous weight above compresses the underlying material in the converging or cone part of the bin resulting in severe packing.

An initial and highly commercially successful solution to the above-mentioned problem is shown in United States Patent No. 3,173,583 for Bin Activator which issued March 16, 1965 to Eugene A. Wadi. in this patent, a bin activator formed of a conically shaped member is substituted for the converging conical shaped outlet of a storage bin. A baffle within the conically shaped member relieves the weight of the overhead material and when the entire bin activator is subjected to vibration, the baffle also prevents preferential flow from the center of the hopper and by sending vibrations into the overhead materials, the baffle promotes the materials downward movement, into the bin activator and then out through the bin activator outlet.The bin activator is vibrationally isolated from the storage bin thereby permitting large vibrational forces to be applied to thebin activator without the need to be concerned with the size of the storage bin or vibration to surrounding structure.

Although the above bin activator was commercially successful, a substantiai improvement was made by providing a substantially flat dish-shaped portion in place of the conically shaped member with a convex baffle placed within the dish-shaped portion. An embodiment of this improved bin activator is shown in United States Patent No. 3,261,508 for Vibratory Bin Activators which issued July 19, 1 966 to Eugene A. Wahl. It was found that the dish-shaped head eliminated the compaction that frequently occurred in the earlier conical configuration.The dish-shaped portion design was based on the finding that a side outlet in a horizontally vibrated container with a flatter bottom was more effective than a bottom outlet for discharging materials because the direction of disengagement of the material particle from the stored mass was in the same horizontal direction as the horizontally applied gyrator force. The improved dish-shaped bin activator incorporates the side outlet concept with a bottom outlet by having the baffle cooperate with the relatively flat floor of the dish to provide a side outlet effect. This is because any vertical bridging between the baffle and the dish bottom will readily respond to the horizontal vibrations.

As fully discussed in Patent No. 3,261,508, a significant advantage of the dish-shaped bin activator over the conically shaped bin activator is that there is an absence of material flow out of the dish-shaped bin activator when the source of vibration such as a gyrator is not operating thereby eliminating the requirement for shut-off gates. Thus the flow out of a storage bin can be provided at a reasonably uniform material rate through the bin activator outlet. A problem can develop if the dish-shaped bin activator is used with a very large storage silo with a requirement that there be a low discharge rate.The low output from the bin activator can cause severe congestion and packing of the material above the bin activator with the congestion and packing being aggravated in the case of sticky materials (such as wet sand) which have a tendency to bridge across even large horizontal distances. It is to the solution of this problem that the present invention is specifically directed.

It is an object of the invention to provide an improved bin activator apparatus for providing a positive, continuous flow of particulated material from a very large storage hopper.

In accordance with this invention therefore we provide apparatus for promoting a small flow of material from a large storage hopper having a discharge opening formed in the bottom thereof, said apparatus comprising: a first activator means having an upper opening and a lower opening smaller than said upper opening; means vibrationally suspending the first activator means from said hopper and in spaced relation to said hopper discharge opening; means for intermitiently vibrating said first activator means; a second activator means having an upper opening to receive material discharged from the lower opening of said first activator means and a lower discharge opening; means vibrationally suspending the second activator means from said first activator means and in spaced relation to said lower opening of said first activator means; and means vibrating said second activator means.

In a preferred embodiment of the invention a bin activator comprises a pair of axially aligned individually vibratable activator portions forming the bottom of a large storage hopper. The upper activator portion is preferably of conical configuration with a baffle member therein to maintain a flow of material therethrough. The upper activator portion is vibrationally isolated from the storage hopper and material flow is promoted by an electro-mechanical gyrator which vibrates the upper activator portion in a plane normal to the hopper axis. The gyrator need only be used intermittently to insure a constant flow of material into the smaller dish-shaped lower activator portion which is vibrationally isolated from the upper activator portion.The lower activator portion includes a convex baffle secured inside to provide an annular path for the flow of material from the upper activator portion and into the discharge opening. Material flow within the lower activator unit is promoted by a second electro-mechanical gyrator.

Figure 1 is a side elevational view of the double gyrator compound bin activator made in accordance with this invention.

Figure 2 is a top plan view with certain parts omitted and a portion of the upper baffle broken away.

Figure 3 is an enlarged, fragmentary crosssectional view taken along the iine 3-3 of Figure 2.

Figures 4 is a schematic drawing showing the theory of operation of the double gyrator compound bin activator.

Referring now to the drawings in detail, wherein like reference numerals indicate like parts throughout the several figures, reference numeral 10 indicates the double gyrator compound bin activator in accordance with the present invention which is adapted to form the bottom portion of a storage hopper H. The bin activator 10 comprises an upper activator section 12 and a lower activator section 14. The upper activator section 12 includes conical portion 16 with an upper opening 18 substantially of the same diameter as the storage hopper H diameter and a lower opening 20.An upper cylindrical portion 22 may surround the upper opening 1 8 to facilitate connecting the upper activator section 12 to the storage hopper H and similarly, the lower opening 20 may include a lower cylindrical portion 24 surrounding the lower opening 20 to facilitate connecting the upper activator section 12 to the lower activator section i 4.

The lower activator section 14 includes a concave or dish-shaped portion 26 with a central opening 28 and an upper cylindrical portion 29 of the same diameter as the lower cylindrical portion 24 of the upper activator section. A discharge member 30 is preferably included at the outlet or central opening 28 of the lower activator section 24 to produce the desired discharge flow characteristics.

The upper activator section 12 is suspended from the storage hopper H by means of forged steel hangers 32. The upper ends of the hangers 32 are pivotally-coupled to bracket plates 34 welded to hopper H and the lower ends of the hangers are similarly coupled to bracket plates 36 welded to upper activator section 12 preferably on cylindrical portion 22. The hangers 32 are provided with rubber bushings to provide necessary vertical rigidity while affording a maximum horizontal flexibility for the upper activator section 1 2 when vibrated. The upper activator section 12 is vibrated substantially in a horizontal plane by means of an electro mechanical gyrator 38 comprising an electric motor having a vertical drive shaft carrying one or more eccentrically mounted weights as is well known in the art.The upper activator section 12 vibration is isolated from hopper H by spacing the upper activator section 12 from the bottom of the hopper H with an elastic sleeve 40 secured in position by a pair of circular metal straps 42, 44.

The elastic sleeve 40 in combination with hangers 32 insure that the upper activator section 12 is relatively free to vibrate in response to the vibratory thrust forces applied thereto by the eccentrically-mounted weights of the gyrator 38.

As will be further discussed below, the gyrator 38 need only be operated intermittently and a timing control (not shown) may be utilized to operate the gyrator at predetermined time intervals.

In a similar manner, the lower activator section 14 is suspended from the upper activator section 12 by means of forged steel hangers 46. The upper ends of the hangers 46 are pivotally coupled to bracket plates 48 welded to conical portion 1 6 and the lower ends of the hangers 46 are similarly coupled to bracket plates 50 welded to lower activator section 1 4 preferably on the concave portion 26. The hangers 46 are also provided with rubber bushings to provide necessary vertical rigidity while affording a maximum horizontal flexibility for the lower activator section 14 when vibrated. The lower activator section 14 is vibrated substantially in a horizontal plane by means of an electro-mechanical gyrator 52 which is essentially a smaller version of gyrator 38.The lower activator section 14 vibration is isolated from the vibration of the upper activator 1 2 by spacing the two sections apart with an elastic sleeve 54 secured in position by a pair of circular metal straps 56, 58. Thus, each activator section is vibrationally independent of the other with the complete bin activator 10 vibrationally independent of the hopper H.

There is preferably positioned within each of the activator sections a baffle which assists in moving the material through each activator section and into the discharge member 28. In the upper activator section 12, a baffle 60 is positioned in the upper part of the conical portion 1 6 and is supported by criss-crossed angle iron bars 62, 64 which extend across the conical portion and are welded thereto. Although the baffle 60 is generally located within the conical portion 16, it may be extended higher in the storage hopper H depending on the size of the hopper and the type of material therein. The baffle 60 is preferably of circular convex configuration and has a diameter substantially equal to the diameter of lower opening 20 so that material cannot fall directly from the hopper H into the lower opening 20. In some instances when used with very large hoppers and with material that is not likely to compact, the upper baffle 60 may be omitted with the vibration on the conical portion 1 6 being sufficient to prevent wedging and compacting of the material as it flows through upper activator section 12.

In the lower activator section, a baffle 66 is positioned within the dish-shaped portion 26 and is supported by spaced angle iron bars 68, 70 which extend across the dished portion 29 and are welded thereto. The baffle 66 is of the same but smaller circular convex configuration as baffle 60 and has a diameter substantially equal to the diameter of central opening 28 so that material from the upper activator section can not fall directly through lower opening 20 into central opening 28.

In operation and with specific reference to Figure 4, the material in storage hopper H will flow around baffle 60 and down through conical portion 1 6 into the lower activator section 1 4.

Because of the larger dimension of the conical portion 1 6 relative to the lower activator section 14, the material M may begin to compact above the baffle 60 and along the sides of the conical portion 1 6. To prevent this compaction and to assist in fluidizing the material M, the gyrator 38 may be intermittently used to produce powerful thrusts V1 which vibrates the upper activator section 12 including the conical portion 16 and the baffle 60 in a horizontal plane. At the same time, the curved baffle 60 resolves the horizontal thrusts into strong vertical impulses lq extending far up into the hopper H, thereby discouraging overhead bridging of the material M.Depending on the type of material M, the intermittent usage of the gyrator 38 can be adjusted by a suitable time control (not shown) to automatically activate the gyrator at set intervals. Consequently, the upper activator section 1 2 effectively fluidizes the material M in the lower portion of the hopper and in the region of baffle 60 as well as along the sides of conical portion 1 6 thereby resulting in a positive, continuous flow of material from the hopper, past the baffle 60 and onto the dishshaped portion 26 of lower activator section 14 where the relatively flat slope of the dish prevents material from compacting.As seen in Figure 4, the material will tend to develop a vertical bridge B between the periphery of the baffle 66 and the floor of the dish, however, the gyrator 52, which is continuously run, will produce powerful thrusts V which vibrate the entire activator section 14 and horizontal force A readily disrupts the bridge and discharges the material through central opening 28. By making the diameter of baffle 66 substantially equal to central opening 28, material from the conical portion 1 6 must necessarily fall onto the dish-shaped portion 26 where horizontal force A will continue the movement of the material M.Because of the low output of material M out of central opening 28, the material M may tend to compact above baffle 66, however, the curved baffle 66 will resolve the horizontal thrusts into strong vertical impulses 12, thereby discouraging such compaction or horizontal bridging of the material.

It will thus be seen that by the use of the above described apparatus, a low output can be produced from a large storage hopper without the usual problem. of compacting and bridging above the outlet. By vibrationally isolating the two sections of the compound bin activator, the possible production of countereffective vibrations is eliminated. An additional advantage of the two isolated sections is that they can be shipped in separate sections and then easily placed together in the field.

Although the preferred embodiment has been described with the upper activator section being a conical portion and the lower activator section being a dish-shaped portion, it will also be understood by those skilled in the art that the upper activator section may be dish-shaped and the lower activator portion may be cone-shaped.

Conceivably, a pair of dish-shaped portions or a pair of cone-shaped portions could also be used, although with most materials, it is preferred that one activator section be dish-shaped to provide an absence of material flow when its related gyrator is stopped.

It will be understood by those skilled in the art that specific geometric shapes discussed above are for use with a circulat storage hopper H and equivalent structural shapes may be used for a square or rectangular shaped hopper.

Claims (9)

1. Apparatus for promoting a small flow of material from a large storage hopper having a discharge opening formed in the bottom thereof, said apparatus comprising: a first activator means having an upper opening and a lower opening smaller than said upper opening; means vibrationally suspending the first activator means from said hopper and in spaced relation to said hopper discharge opening; means for intermittently vibrating said first activator means; a second activator means having an upper opening to receive material discharged from the lower opening of said first activator means and a lower discharge opening; means vibrationally suspending the second activator means from said first activator means and in spaced relation to said lower opening of said first activator means; and means for vibrating said second activator means.

2. The apparatus as recited in Claim 1 wherein a first baffle member is secured to said first activator means and a second baffle member is secured to said second activator means.

3. The apparatus as recited in Claim 2 wherein said first activator means includes a conical portion and said first baffle member is secured to said conical portion and has a peripheral surface spaced from the inner walls thereof.

4. The apparatus as recited in Claim 3 wherein said second activator means includes a dishshaped portion including said lower discharge opening and said second baffle member is secured to said dish-shaped portion and has a peripheral surface spaced from the inner walls thereof.

5. The apparatus as recited in Claim 4 wherein the said first and second baffle members are convex members.

6. The apparatus as recited in Claim 5 wherein said first and second baffle members are spaced from each other along the hopper axis and said first baffle member has a larger area than said second baffle member.

7. The apparatus as recited in Claim 6 wherein said first baffle member has a diameter substantially equal to the lower opening of said first activator means and wherein said second baffle member has a diameter substantially equal to said lower discharge opening of said second activator means.

8. The apparatus as recited in any one of Claims 1 to 7 wherein said means for intermittently vibrating said first activator means is a gyrator attached to said first activator means and wherein said means for vibrating said second activator means is a gyrator attached to said second activator means, each gyrator comprising at least one eccentrically mounted weight rotatable by an electric motor.

9. The apparatus as recited in any one of Claims 1 to 8 including first resilient means adapted to couple said first activator means to said hopper and second resilient means coupling said first activator means to said second activator means.

1 0. Apparatus substantially as described herein with reference to the accompanying drawings.