Apparatus and system for atmospherically controlling the removal of a bulk bag from an unloader

Abstract

An apparatus and system for removing material from a bulk bag with reduced atmospheric contamination. The invention provides for engaging the bulk bag in a substantially airtight arrange with a reservoir that receives the material being unloaded and airflow discharge system that filters the airflow prior to it entering the surrounding atmosphere. The apparatus is specifically intended for removing residual material from the bulk bag and collapsing the bag through vacuum pressure. This simplifies bag removal and folding while reducing atmospheric contamination from uncontrolled residual material.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from and benefit of U.S. Provisional Patent Application No. 60/289,725, filed on May 9,2001, entitled “Bulk Bag Vacuum System,” which is hereby incorporated by reference in its entirety as if fully set forth herein. This application also claims priority from and benefit of U.S. Provisional Patent Application No. 60/318,703, filed on Sep. 12, 2001, entitled “Bulk Bag Vacuum System,” which is hereby incorporated by reference in its entirety as if fully set forth herein.

BACKGROUND

[0002] The present invention relates to bulk bag dispensing systems and, more specifically, to a bulk bag system and method for handling bulk bags having residual while significantly reducing or eliminating the contaminants generated during that process. This significant reduction in contaminants results in cleaner manufacturing sites, longer operable life for on-site machinery, and reduced health hazzards to operators and handlers.

[0003] Bulk bags are typically made of heavy woven material with heavy duty straps for supporting the bulk bag when it is hung in a tower-like supporting frame. Bulk bags typically have a material unloading outlet that is closed by a draw and tie string. Typical bulk bags hold between approximately two thousand (2,000) pounds and two thousand five hundred (2,500) pounds. However, depending on the application used with the bulk bag dispensing system, the bulk bags can be much heavier or much lighter. A standard bulk bag, commonly referred to as a one ton bag, has a volume of about sixty-four (64) cubic feet.

[0004] The bulk bag is generally sized to fit on a standard pallet and the actual weight of the bulk bag will depend on the density of the enclosed bag contents. After emptying, the bulk bag frequently still contains residual trapped in the bulk bag. Additionally, some resistance to the complete emptying of the contents from the bag may be created by the physical characteristics of the bag or its contents.

[0005] After emptying the bag, an operator removes it from the unloading system and folds it into a more compact form. This process results in residual material being ejected into the surrounding atmosphere. This ejected material creates pollutants that are detrimental to the health of on-site personnel and factory equipment.

[0006] What the art needed was a system that significantly reduced or eliminated these pollutants in the surrounding atmosphere.

SUMMARY

[0007] An apparatus for reducing atmospheric contamination caused by the release of a material from a bulk bag when the bulk bag is removed from a bulk bag unloader that transfers the material from the bulk bag to a reservoir. The apparatus has a conduit for establishing an airflow path between the reservoir and a vacuum source. The conduit has first and second ends with one end in a generally airtight connection to the reservoir and the other in a generally airtight connection to the vacuum source. The preferred vacuum source draws about 0.0074 Atmospheres which is sufficient to cause the bulk bag to draw in upon itself.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing summary, as well as the following detailed description of the preferred embodiment of the present invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings an embodiment which is presently preferred. It is understood, however, that the invention is not limited to the precise arrangement and instrumentality shown. In the drawings:

[0009] FIG. 1 is a front elevation of a bulk bag unloading system including a residual material removal system according to a preferred embodiment of the invention;

[0010] FIG. 2 is an elevation, along the line 2-2, of the system of FIG. 1 with the bulk bag removed; and

[0011] FIG. 3 is a top plan view, along the line 3-3, of the system of FIG. 2.

[0012] FIG. 4 illustrates a bulk bag in a collapsed condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left,” “lower,” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the system for removing material from a bulk bag and designated parts thereof. The terminology includes the words above specifically mentioned, derivatives thereof and words of similar import.

[0014] Referring to the drawings in detail, wherein like numerals indicate like elements throughout, there is shown in FIGS. 1-3 a preferred embodiment of the invention for removing residual material from a bulk bag. The present invention is particularly useful with known unloading system, such as describe in U.S. Pat. Nos. 5,184,759; 6,290,098; and 6,340,100 which are commonly owned with the present application and are incorporated herein by reference as if fully set forth herein. Generally speaking, a bulk bag 12 is suspended within a supporting frame 14 so that material 16 can be unloaded into a hopper or reservoir 18. An airtight discharge system is connected to hopper 18 so that air displaced by the material entering the hopper 18 is conveyed through the tube 22 and is filtered prior to being discharged into the surrounding atmosphere 74.

[0015] Preferably, a vacuum source 20 is connected to the air discharge system 10. While the system 10 could be used without operating the vacuum source 20during general unloading, the vacuum source 20 is used at the end of the bag emptying to vacuum out any air and residual material in the bag. As will be explained later this collapses the bag and simplifies bag removal while improving environmental control. Use of the vacuum during unloading may also promote material flow.

[0016] Once the material 16 is removed from the bulk bag 12, the vacuum source 20 of this embodiment is operated to create a vacuum of 0.0074 Atmospheres. Depending on the bag and its material content, vacuum as low as 0.0025 Atmospheres may be sufficient. The preferred vacuum has been shown to be sufficient to vacuum out substantially all of the remaining air and material from the inside of the bulk bag 12. This causes the bulk bag 12 to be drawn inwardly and significantly decreases the bulk of the empty bag. Presently, it is preferred that the top of the bulk bag 12 be raised to facilitate the collapsing of the bulk bag 12, see FIG. 4.

[0017] Once the bulk bag 12 has dispensed the material 16 and been vacuumed, an operator can close the bag spout 38 and remove the bulk bag 12 with a minimal amount of material particulate 16 being expelled from the bulk bag 12. By significantly reducing the amount of pollutants ejected into the surrounding atmosphere during the bulk bag 12 emptying process, this system 10 dramatically decreases the risk to the health of on site personnel and increases the useful operating life of on site machinery.

[0018] Unless otherwise stated, it is preferred that the supporting frame 14 and its various components are formed of a rigid, high strength, durable material, such as stainless steel. However, those of ordinary skill in the art will appreciate from this disclosure that, depending upon the specific application for which the bulk bag system is designed various structural components can be formed of other materials, such as a heavy duty polymer, alloy, aluminum, steel or the like without departing from the scope of the present invention.

[0019] The supporting frame 14 preferably a tower configuration as described in the above referenced patents. In the illustrated embodiment, a rectangular framing array 24 provides a safety frame work which is intended to partially support the bulk bag 12 should one or more of the bulk bag straps break or tear. The rectangular framing array also supports one end 26 of first and second plates 28A, 28B that are used to adjust the shape of the bulk bag and encourage full material flow out of the bag. The framing arrays 30 are preferably located at various locations along the supporting frame 14 to further stabilize the bulk bag system.

[0020] The vacuum source 20 is preferably supported on a side mount 32 that is formed by a tubular platform 34 attached to the supporting frame 14. A distal end of the tubular platform 34 is preferably supported by at least one inclined beam 36 that is connected on one end to the distal end of the tubular platform 34 and is connected on another end to the supporting frame 14. Those of ordinary skill in the art will appreciate from this disclosure that the vacuum source 20 can be mounted on the supporting frame 14 or remotely located without departing from the scope of the present invention. Similarly, those of ordinary skill in the art will appreciate from this disclosure that the overall shape, orientation, and structural materials of the supporting frame 14 can vary without departing from the scope of the present invention.

[0021] At the lower end of the bulk bag 12 is a bag spout 38. The bag spout 38 is attached to a dispensing tube 40 and secured thereto via a circular clamp 42. The dispensing tube 40 is joined to opening 68 in the top of the hopper 18. The dispensing tube 40 is engageable with the spout 38 to establish a generally airtight connection between the bag 12 and the system discharge10. This also serves to maintain the bag spout 38 in alignment with the material reservoir or receptacle.

[0022] During the dispensing process, it is common for some materials to form a column-like hollow structure in the remaining material. Those skilled in the art will recognize this as the material's angle of repose. When such a column forms, the dispensing efficiency of the remaining material 16 is reduced. To prevent such dispensing inefficiencies, an inward pressure is preferably exerted on the lower sides of the bulk bag 12.

[0023] One preferred method of exerting inward pressure on the lower portion of the bulk bag 12 is to rotate the first and second plates 28A, 28B generally inwardly into the bulk bag 12 to maintain the proper angle of repose for the material 16 within the bulk bag 12. Other than their respective location and orientation along the supporting frame 14, the first and second plate 28A, 28B operate in a similar fashion and, accordingly, only the operation of the first plate 28A will be described below.

[0024] A rightward end of the first plate 28A is pivotally secured to the rectangular framing array 24 at a position beneath a lower end of the bulk bag 12. A cylinder 44 is preferably used to rotate the first plate 28A generally upwardly and inwardly into the bulk bag 12 in a generally clockwise fashion about the pivotally secured plate end 26 to exert an inwardly directed force on the lower portion of the bulk bag 12. The cylinder 44 has a first end securely mounted to the support frame 14 at a location that is preferably beneath the lower end of the bulk bag 12. A second end of the cylinder 44 supports a piston 46 that can be extended outwardly from the cylinder 44 to rotate the first plate 28A in the clockwise direction. Thus, by extending and retracting the piston 46, the cylinder 44 can control the position of the first plate 28A in order to supply the necessary inwardly directed force to the lower portion of the bulk bag 12. It is preferred, but not necessary, that the first and second plates 28A, 28B operate in unison in a generally synchronized fashion.

[0025] The term “generally airtight” as used herein means being “substantially closed to the surrounding atmosphere so that material moving between the bag and the reservoir is confined and air is directed to flow through the discharge system.” Thus, finer materials, like talc, are more difficult to contain then courser materials, like plastic pellets.

[0026] The system discharge commonly is at least passively filtered before exposing the escaping air to the surrounding atmosphere 74. Such filtration may be by means of a sock filter or similar device. In the present embodiment, passive filtration is accomplished with the filter element 52, which is a pleated circular filter that is available from MPF as model 900209, positioned in chamber 51 above the inverted funnel 23. The filter element 52 has a closed bottom and an open top, for the reasons discussed hereinafter. Those of ordinary skill in the art will appreciate that passive filtration may be accomplished in other ways and that the primary concern is to block air discharge, and, in the present invention, guard the vacuum source 20 against air borne material.

[0027] The vacuum source 20 is preferably positioned at the end of the airflow path 62 and, preferably, is open to the atmosphere even when it is not in operation. In operation, the presently preferred vacuum source 20 provides an air flow of approximately four hundred three (403) cubic feet per minute at about three (3) inches of standing water pressure. It has been found that a vacuum source operated at between approximately one (1) and approximately six (6) inches of standing water pressure will provide the benefits of the present invention. However, those of ordinary skill in the art will appreciate that the particular operating vacuum can be varied depending upon the material and bag application for which the invention is used. For example, lighter more hazardous materials in bags made of very heavy bag material may require greater vacuum based on the bag. Likewise, easily collapsed bags may call for less vacuum.

[0028] In the preferred embodiment, a reverse flow device 56 is positioned between the vacuum source and the filters. The reverse flow device 56 has an outlet nozzle 58 aligned to direct a pressurized fluid, such as air, through the filters 52 and into the chamber 51. Preferably, the reverse flow device 56 operates periodically and directs air toward the chamber 51 to dislodge material 16 captured by the filter 52. The preferred reverse flow device 56 delivers an air pulse of approximately eighty (80) pounds per square inch at the nozzle 58. Although the reverse flow device may be operator adjusted, the off portion of the pulse is preferably set at a duration of between approximately five (5) seconds and approximately ten (10) seconds and the on pulse is set between approximately two tenths (0.2) of a second and approximately two point five (2.5) seconds. The reverse flow device may be used with passive filtration as well as active filtration with vacuum source 20. Dislodged material is returned to the reservoir for further handling. This helps to reduce the uncontrolled material which could be discharged to the atmosphere when the bag is removed.

[0029] The present invention, even if operated only when the bag is substantially empty, provides for removal of material from a bulk bag with reduced atmospheric contamination. The vacuuming of the bulk bag 12 prior to it being removed and folded allows on-site personnel to fold the bulk bags 12 without ejecting a substantial amount of material particles into the atmosphere 74.

[0030] The present invention makes it possible to handle empty bulk bags 12 without any significant contamination of the atmosphere during the bag removal process.

Claims

1. A material handling bulk bag evacuation system for reducing atmospheric contamination caused by the release of residual material from the bag, the system comprising:

a reservoir connected to the bag in a generally airtight connection for receiving material discharged from the bulk bag;

a conduit establishing an airflow path between the reservoir and a vacuum source and having first and second ends with one end thereof in a generally airtight connection to the reservoir and the other in a generally airtight connection to the vacuum source; and

the vacuum source draws sufficient vacuum to draw the bulk bag in upon itself.

2. The system of claim 1 wherein the vacuum is sufficient to remove residual material from the bag.

3. The system of claim 1 wherein a filter array is disposed between the reservoir and the vacuum source.

4. The system of claim 3 wherein the vacuum is sufficient to remove residual material from the bag.

5. The system of claim 1wherein the vacuum source is operated after the bulk bag has been emptied into the reservoir.

6. The system of claim 5 wherein the vacuum is sufficient to remove residual material from the bag.

7. The system of claim 6 wherein a filter array is disposed between the reservoir and the vacuum source.

8. An apparatus for reducing atmospheric contamination caused by the release of a material from a bulk bag when the bulk bag is removed from a bulk bag unloader that transfers the material from the bulk bag to a reservoir, the apparatus comprising:

a conduit for establishing an airflow path between the reservoir and a vacuum source;

the conduit having first and second ends with one end thereof in a generally airtight connection to the reservoir and the other in a generally airtight connection to the vacuum source; and

the vacuum source draws sufficient vacuum to draw the bulk bag in upon itself.

9. The apparatus of claim 8 wherein the vacuum is sufficient to remove residual material from the bag.

10. The apparatus of claim 8 wherein a filter array is disposed between the reservoir and the vacuum source.

11. The apparatus of claim 10 wherein the vacuum is sufficient to remove residual material from the bag.

12. The apparatus of claim 8 wherein the vacuum source is operated after the bulk bag has been unloaded into the reservoir.

13. The apparatus of claim 12 wherein the vacuum is sufficient to remove residual material from the bag.

14. The apparatus of claim 13 wherein a filter array is disposed between the reservoir and the vacuum source.

15. A system for reducing atmospheric contamination caused by the release of residual material from a material handling bulk bag have means for holding the bag at a predetermined location and a spout for emptying the bag at a second location, the system comprising:

a frame for suspending the bag above a material receiving reservoir with the bag spout disposed toward and in a generally airtight connection with the reservoir;

a conduit establishing an airflow path between the reservoir and a vacuum source and having first and second ends with one end thereof in a generally airtight connection to the reservoir and the other in a generally airtight connection to the vacuum source; and

the vacuum source draws sufficient vacuum to draw the bulk bag in upon itself.

16. The system of claim 15 wherein the vacuum is sufficient to remove residual material from the bag.

17. The system of claim 15 wherein a filter array is disposed between the reservoir and the vacuum source.

18. The system of claim 15 wherein the frame is movable vertically.

19. The system of claim 18 wherein the a filter is disposed between the reservoir and the vacuum source.

20. The system of claim 19 wherein the vacuum source provides an air flow of about four hundred (400) cubic feet per minute at about three (3) inches of standing water pressure.