METHOD AND APPARATUS FOR PROCESSING PLASTIC LINER BAGS

Abstract

A method and apparatus for opening of a plastic bag containing a food product in the form of powder or similar fine particulate material is disclosed. The bag is positioned atop a plate with a plurality of slots, with at least one slot transverse to the others. Beneath the plate, a bag opener is provided that includes a plurality of blades, with at least one blade transverse to the others. The plastic bag is penetrated with aeration spears and pressurized. The bag opener is moved relative to the plate such that the blades pass through the slots and open the bag. The plate is then allowed to pivot downwards, allowing its contents to be emptied into a hopper beneath the plate.

Claims

1. A method of processing a plastic liner bag filled with contents, the method comprising: positioning a lower surface of the plastic liner bag on a plate configured with at least two slots, wherein the at least two slots are substantially perpendicular to each other; penetrating a surface of the plastic liner bag with one or more aeration spears; inflating the plastic liner bag with a gas delivered from the one or more aeration spears, thereby fluidizing the contents; and cutting the lower surface of the inflated plastic liner bag with a bag opener, wherein the bag opener is configured with at least two blades, and the at least two blades are substantially perpendicular to each other and pass through the slots of the plate.

2. The method as claimed in claim 1, wherein the plastic liner bag is pushed onto the plate.

3. The method as claimed in claim 1, wherein the one or more aeration spears are displaced vertically downwards to penetrate the plastic liner bag.

4. The method as claimed in claim 1, wherein a seal is formed around the penetrated surface of the plastic liner bag prior to inflating the plastic liner bag.

5. The method as claimed in claim 1, wherein the gas is an inert gas.

6. The method of claim 1, wherein the bag opener is moved vertically upwards relative to the plate to cut the lower surface of the bag.

7. The method of claim 1, wherein the plate is moved vertically downwards relative to the bag opener to cut the lower surface of the bag.

8. The method of claim 1, further comprising: after the plastic liner bag has been cut, pivoting at least a portion of the plate downwards to empty the plastic liner bag.

9. The method as claimed in claim 1, wherein the contents of the plastic liner bag comprise milk powder.

10. An apparatus used in the method of processing a plastic liner bag filled with contents as claimed in claim 1, the apparatus comprising: a plate to receive the plastic liner bag; one or more aeration spears arranged to penetrate a surface of and deliver a gas into the plastic liner bag; a bag opener configured to open the plastic liner bag; and a vessel arranged beneath the plate to receive the contents of the plastic liner bag once opened, wherein the plate is configured with at least two slots, the at least two slots are substantially perpendicular to each other, the bag opener is arranged beneath the plate and is configured with at least two blades, and the at least two blades are substantially perpendicular to each other and, in use, pass through the slots of the plate.

11. The apparatus as claimed in claim 10, wherein the apparatus comprises a housing containing the plate and the bag opener.

12. The apparatus as claimed in claim 10, wherein the apparatus comprises a conveyor for the plastic liner bag.

13. The apparatus as claimed in claim 12, wherein the apparatus comprises a pusher device arranged to move the plastic liner bag from the conveyor to the plate.

14. The apparatus as claimed in claim 10, wherein the apparatus comprises a bag holding means configured to contact and engage the plastic liner bag when on the plate.

15. The apparatus as claimed in claim 14, wherein the bag holding means comprises one or more vacuum gripping devices.

16. The apparatus as claimed in claim 10, wherein the one or more aeration spears is configured with an outer housing configured as an annular ring and including a series of vacuum points, and

17. The apparatus as claimed in claim 10, wherein the apparatus includes a displacement means for the one or more aeration spears, and the displacement means is configured to move the aeration spears substantially vertically downwards.

18. The apparatus as claimed in claim 10, wherein one of the at least two slots of the plate intersects the other of the at least two slots.

19. The apparatus as claimed in claim 10, wherein the plate is configured with at least three slots, and a first slot is relatively elongate and bisected by a second slot and third slot spaced equidistantly apart.

20. The apparatus as claimed in claim 10, wherein the plate is formed from two or more segments, and the slots are formed between adjacent segments.

21. The apparatus as claimed in claim 20, wherein an edge or side of each segment is hinged.

22. The apparatus as claimed in claim 10, wherein the plate is mounted to a frame including a displacement means, and the plate is configured to be displaced vertically downwards relative to the bag opener.

23. The apparatus as claimed in claim 10, wherein one of the at least two blades of the bag opener intersects the other of the at least two blades.

24. The apparatus as claimed in claim 10, wherein the bag opener includes at least three blades, and a first blade is relatively elongate and bisected by a second and third blade spaced equidistantly apart.

25. The apparatus as claimed in claim 10, wherein the at least two blades of the bag opener are mounted to a frame, and the bag opener comprises a displacement means that is operative on the frame.

26. The apparatus as claimed in claim 25, wherein the bag opener is configured to be displaced vertically upwards relative to the plate.

27. The apparatus as claimed in claim 10, wherein the apparatus comprises a control system including a programmable logic controller, and the PLC receives inputs from sensors provided to the apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order that the advantages of certain embodiments of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. While it should be understood that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0068] FIG. 1 is a perspective view of a bag opening station and conveyor according to one aspect of the present invention;

[0069] FIG. 2 is an end view of the bag opening station of FIG. 1;

[0070] FIG. 3A is an upper perspective view of the bag opener according to one aspect of the present invention;

[0071] FIG. 3B is a lower perspective view of the bag opener according to one aspect of the present invention;

[0072] FIG. 4A is a cross-sectional view of the bag opening station of FIGS. 1 and 2 during inflation of a bag;

[0073] FIG. 4B is a detail view of FIG. 4A;

[0074] FIG. 5 is a cross-sectional view of the bag opening station of FIG. 4A during operation of the bag opener to open the bag; and

[0075] FIG. 6 is a cross-sectional view of the bag opening station of FIGS. 4A and 5 as the bag is emptied.

[0076] Unless otherwise indicated, similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION

[0077] Some embodiments pertain to methods and apparatus for opening a plastic bag containing a food product in the form of powder or similar fine particulate material. The bag is positioned atop a plate with a plurality of slots, with at least one slot transverse to the others. Beneath the plate, a bag opener is provided that includes a plurality of blades, with at least one blade transverse to the others. The plastic bag is penetrated with aeration spears and pressurized. The bag opener is moved relative to the plate such that the blades pass through the slots and open the bag. The plate is then allowed to pivot downwards, allowing its contents to be emptied into a hopper beneath the plate.

[0078] It is an object of some embodiments to provide a method and apparatus for the processing and emptying of a plastic liner bag from which an outer coarse paper bag has been removed. It is an object of certain embodiments to provide a method and apparatus for the automated, or near automated, processing and emptying of a plastic liner bag from which an outer coarse paper bag has been removed. It is an object of some embodiments to provide a method and apparatus for the efficient emptying of a plastic liner bag from which an outer coarse paper bag has been removed. It is an object of certain embodiments to provide a method and apparatus for the automated emptying of a plastic liner bag without having to tilt the bag into a vertical or near vertical orientation. It is an object of some embodiments to provide a method and apparatus for the opening of a plastic liner bag from which an outer coarse paper bag has been removed without having portions of plastic material becoming entrained with the contents of the bag as it is emptied. It is an object of certain embodiments to at the very least provide the public with a useful choice.

[0079] An embodiment of the present invention is shown in FIGS. 1 and 2 as part of a bag opening station (generally indicated as 100) in a facility processing Kraft bags B. These types of bags have an outer bag of paper protecting an inner plastic liner bag that contains a food powder.

[0080] For the sake of describing an embodiment and the method of its use, reference shall now be made to the food powder being milk powder but it should be understood that this is not meant to be limiting. In certain embodiments the food powder may be flour or icing sugar, for example. As with milk powders, these powdered products are often referred to as being sloppy and are very fluid in the plastic liner bag such that they may easily flow.

[0081] The facility processing Kraft bags may be a food manufacturing plant or the like which requires a suitably hygienic environment in which the food is made and prepared. For example, the facility may be a manufacturer of infant formula which have multiple powdered constituents, such as the milk powders whey and casein, to be brought together and blended. Prior to doing so, each of the constituents are provided to the facility in Kraft bags which must therefore be processed and emptied.

[0082] As part of the bag handling process, the outer paper bag of the Kraft bag B has already been removed and the plastic liner bag placed on a conveyor 102. The conveyor may be a belt-type conveyor, as depicted in FIG. 1, or one using a plurality of segmented plates, depending on the preferred configuration.

[0083] The conveyor 102 transports the plastic liner bag B to the bag opening station 100 which, to avoid or minimize contamination of the contents of the bag, may be located in a more hygienic section of the facility for opening and emptying. At the bag opening station, the milk powder contained in the plastic liner bag is emptied into a suitable vessel, such as a hopper 104. In FIG. 2, the hopper can be seen beneath the bag opening station.

[0084] As can be seen in FIG. 1, a series of plastic liner bags B approach the bag opening station 100 via the conveyor 102. Each plastic liner bag has been located such that it is laid on its wider side, horizontally on the conveyor.

[0085] As shown in FIGS. 1 and 2, the bag opening station 100 includes a large housing 106, adjacent to the conveyor 102, within which the opening and the emptying of the plastic liner bag B is performed. The presence of the housing 106 also acts to minimize and confine any airborne distribution of the milk powder contained in the bag B as it is opened and emptied. This minimizes any loss of the milk powder.

[0086] In the illustrated example, the bag opening station 100 includes an orientation system 108 to ensure correct alignment of the plastic liner bag B prior to it being transferred from the conveyor 102 into the housing 106. The orientation system may use lasers 108a or the like to help determine whether the plastic liner bag is in the appropriate position for transfer. Upon the lasers detecting the presence of the bag, the orientation system may issue a signal that prompts the conveyor to be momentarily paused to allow the transfer of the bag B into the housing to take place.

[0087] In the illustrated example, the orientation system 108 includes a pusher 108b which urges against the side of the plastic liner bag in order to transfer it from the conveyor 102 and into the housing 106 for the opening procedure to take place.

[0088] As shown in FIG. 1, the housing 106 includes a door 110 proximate the conveyor 102. Upon a plastic liner bag B reaching the area adjacent the door and subject to being correctly orientated, the door is opened and the pusher 108b moves the plastic liner bag into the housing. The pusher then retracts and the door to the housing is closed, thereby substantially sealing the housing in preparation for the opening and emptying of the plastic liner bag.

[0089] In the example of FIG. 1, a worker W operates the pusher by activating a switch that is present on an operating panel 112. This means the worker does not contact the bag B itself, thus eliminating a potential source of contamination. However, it should be appreciated that part of or the entire bag opening process may be automated through the use of an appropriately programmed control system incorporating a programmable logic controller (PLC) or the like.

[0090] For example, in an embodiment not illustrated here, the PLC may control the advance of the conveyor, the location of the bags B being monitored though the use of lasers or similar equipment which detect and measure the length and width of the plastic liner bag. Once the plastic liner bag has been determined to be in the correct position to be transferred into the housing of the bag opening station, the door is opened and the pusher applied to the bag by the PLC to move it through the door of the housing and into the appropriate position for the bag opening process. The door is then closed behind and the conveyor resumes its advance, bringing another bag to the bag opening station.

[0091] Although the plastic liner bag B is shown in FIGS. 1 and 2 orientated such that its elongate dimension is in line with the direction of travel of the conveyor 102, this is not essential. The plastic liner bag could be placed such that its shorter dimension is in line with the direction of travel of the conveyor, subject to the overall width of the conveyor. It will be appreciated that in this instance, the pusher 108b may act upon the top or base of the bag into order to move it into the bag opening station 100.

[0092] Integrated into the upper portion of the housing are a pair of aeration spears 114. These are elongate structures with a piercing tip (not visible in FIGS. 1 and 2) that can be displaced downwards, into the housing 106. The spears are hollow and conduct a compressed gas.

[0093] The interior of the housing 106 includes a plurality of vacuum grippers (not visible in FIGS. 1 and 2) which, once the plastic liner bag B has been transferred into the housing, contact its outward facing surfaces. These apply a suction force to secure the plastic liner bag in preparation for opening. The use of vacuum grippers for securing plastic liner bags is widely used in the bag processing industry and persons skilled in the art will readily implement such arrangements.

[0094] Once it has been transferred to the housing 106, the plastic liner bag B rests on a substantially horizontal plate (not visible in FIG. 3).

[0095] The plate includes a plurality of slots. These slots are formed by virtue of the plate being formed from a plurality of segments rather than as a one-piece and unitary structure. At least some, preferably all, of the segments have an edge that is provided with a hinging means connecting it to the surrounding housing structure. The hinging means is such that it allows the segment to be able to pivot downwards.

[0096] In exemplary embodiments, the plate is configured with three slotsone relatively elongate slot, with two shorter slots arranged perpendicular to, and bisecting, the elongate slot. This means that the plate is effectively made up of six segments. However, it should be appreciated that in some examples, the plate may only be provided with two slots, transverse to each other, such that the plate is only made up of four segments.

[0097] It will be appreciated that the slots of the plate are substantially in correspondence with the blades of the bag opener 300, which is shown in FIGS. 3A and 3B, from the upper and lower sides respectively. As can be seen, the bag opener includes a plurality of serrated cutting blades 302, 302a mounted to a frame 304 linking the blades such that the bag opener forms a unitary structure.

[0098] As seen in FIGS. 4A, 4B, 5 and 6, the bag opener 300 is positioned within the lower portion of the bag opening station 100 (housing omitted for sake of clarity), below the plate 400. In this example, it is positioned above the entrance to the hopper 104 but in other examples, it may be positioned in the mouth of the entrance to the hopper.

[0099] Returning to FIGS. 3A and 3B, the bag opener 300 is linked to a support structure (not visible) via a piston 306. The piston causes movement of the frame 304 and the cutting blades 302 mounted thereto upwards and away from the support structure.

[0100] In the embodiment illustrated in FIGS. 3A and 3B, the bag opener is formed from five blades, one 302a of which is perpendicular or transverse to the other four blades 302. However, it should be appreciated that in some embodiments, the bag opener may be formed from two or three interlocking blades.

[0101] Given its central position, the transverse blade 302a is connected to the piston 306. This ensures relatively equal distribution of forces across the length of the blades 302 as they contact the plastic liner bag during the opening process.

[0102] The use of the invention shall now be described with reference to FIGS. 4A, 4B, 5 and 6. The plastic liner bag B containing milk powder approaches the bag opening station 100 along the conveyor (not shown). Once it has reached the appropriate position, it is then transferred into the housing (not shown), either manually or automatically.

[0103] As shown in FIG. 4A, when in the housing (not shown), the aeration spear 114 (only one is shown in this figure) is displaced vertically downwards such that its tip penetrates the upward facing side of the plastic liner bag B. The housing 114a surrounding the spear is provided with vacuum grippers 114b. This is to create an adequate and robust seal around the entry point of the spear into the plastic liner bag. A supply of compressed gas, such as nitrogen, preferred since it is biologically inert and will not affect the powder, is then introduced to the plastic liner bag via the aeration spears.

[0104] As the entry point of the aeration spear 114 is effectively sealed by the housing 114a and vacuum grippers 114b, the effect of the compressed gas is to inflate the plastic liner bag B and fluidize its contents. The inflation urges the lower side of the plastic liner bag into the slots 402 of the plate 400, best seen in FIG. 4B, a detail view of the area identified as A in FIG. 4A, increasing the surface tension of the material of the bag. This means that the cutting of the plastic liner bag, even by a relatively small piercing force, is relatively efficient.

[0105] Turning to FIG. 5, in which the housing 106 is shown and instead of a single aeration spear, two are depicted, the next step in the bag opening process is the advancement of the bag opener 300 upwards such that at least a portion of its cutting blades 302 enter and pass through the slots (402 in FIG. 4B) to pierce the lower surface of the plastic liner bag B, thereby opening it. The surface of the bag, being placed under considerable tension due to being inflated, is easily pierced.

[0106] The bag opener 300 is then withdrawn and the plate 400 allowed to pivot downwards about hinge points 600 as shown in FIG. 6. This allows the milk powder contained within the bag B to be emptied into the hopper 104 positioned beneath the bag housing station 100. The aeration spears 114 are now surplus to requirements and may also be withdrawn. However, in some examples, they may continue to emit compressed gas as they are withdrawn to help clear any powder that may have been caught by surfaces within the bag opening station, such as the plate or the piston 306 or support structure (not shown) of the bag opener 300.

[0107] The use of the vacuum grippers 114b in the housing 114a to secure the plastic liner bag B means that it does not enter the hopper 104. Instead, the vacuum grippers remove the bag from the housing 106 by dropping into a waste chute (not shown).

[0108] An advantage of some embodiments is that the bag opener 300, with its arrangement of five blades 302, 302a in the exemplary embodiment, operates in such a way that the lower surface of the plastic liner bag B is cut into a group of flaps. Each flap remains connected to the remainder of the bag along at least one edge. This means that there is little or no risk of any separate plastic elements entering the hopper 104, into which the plastic liner bag's contents are emptied. It also helps maximize the efficiency of the emptying process since it optimizes the elimination of any powder that has collected in the corners of the plastic liner bag.

[0109] Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of including, but not limited to.

[0110] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavor in any country in the world.

[0111] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0112] Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

[0113] It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

[0114] It will be readily understood that the components of various embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the present invention, as represented in the attached figures, is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention.

[0115] The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, reference throughout this specification to certain embodiments, some embodiments, or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases in certain embodiments, in some embodiment, in other embodiments, or similar language throughout this specification do not necessarily all refer to the same group of embodiments and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0116] It should be noted that reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

[0117] Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.

[0118] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.