WO2003000553A1

WO2003000553A1 - Densifying bag filling machine

Info

Publication number: WO2003000553A1
Application number: PCT/US2002/014571
Authority: WO
Inventors: Harold Mcgregor
Original assignee: Mcgregor, James
Priority date: 2001-05-04
Filing date: 2002-05-06
Publication date: 2003-01-03

Abstract

A bag filling machine capable of densifying particulate material in the bag being filled is herein disclosed. The bag filling machine comprises a shroud (20), spout (50), plug (32) and a bag filling tube (30) that is inserted in a bag (B) so as to seal the bottom end of the bag filling tube against the bottom of the bag. Particulate material is introduced into the bag filling tube (30), which is then sealed by the plug (32) and has a vacuum drawn therein to remove air from the particulate material. Air is then rapidly introduced into the sealed bag filling tube (30) from an air tube (36) to compact the particulate material. The bag filling tube (30) is then withdrawn from the bag leaving the compacted particulate material in the bag.

Description

DENSIFYING BAG FILLING MACHINE

FIELD OF THE INVENTION

The present invention relates to a bag filling device for filling bags with flowable particulate materials in an efficient and reliable manner. More specifically, the present invention relates to a bag filling machine that densifies the flowable particulate materials as the bag is filled.

BACKGROUND OF THE INVENTION

In filling bags with particulate materials, it is often very desirable to density the materials within the bags. Not only does this permit the placement of more material within a bag, but can also prevent situations in which excess air within the bag essentially inflates the bag, thereby causing it to rupture when additional bags are placed or stacked thereon. Typically, densification is achieved through the vibration of the particulate materials either before or after they are placed within the bag. This vibration can be accomplished by vibrating the bin or hopper within which the particulate materials are stored, or by placing a vibrating element within a filled bag so as to remove air therefrom. Another method of densifying particulate materials within a container is to first pull a vacuum within the container and to suddenly reintroduce air into the container such that the air rushing back into the bag acts as an air hammer. Pulling a vacuum in the container tends to remove air from between the individual particles of the particulate material and the air hammer action of the air rushing back into the container acts to compact the materials. Using any of these methodologies, particulate materials may be densified within a bag. Unfortunately, each of these methodologies has certain drawbacks. Vibration of particulate materials is not as complete as drawing a vacuum and using an air hammer. In addition, continued and excessive vibration of the bag filling machine by a vibrating device can cause physical damage to the bag filling machine itself. The use of a vacuum and air hammer, while providing superior densification of the particulate materials, has in the prior art been carried out in a two part process wherein the container used to density the particulate material is separate from the bag, drum, or box that the particulate material will ultimately be placed in. As can be appreciated, this two step process requires more time and equipment to carry out than would a combined process.

Therefore, there is a recognized need for a structure and method for combined densification and filling of particulate materials that also has a relatively high fill rate.

These and other objectives and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.

SUMMARY OF THE INVENTION

The objects of the present invention are substantially met by a densifying bag filling machine comprising a material supply mechanism that is connected to a bag filling shroud, a bag filling tube located within the shroud and reciprocable therewith. The bag filling tube travels between an upper position and a lower position within in the shroud and is moved by an actuator mechanism. The upper end of the bag filling tube has a funnel-like shape that mates with a correspondingly shaped lower, bag filling end of the shroud. When mated, particulate material supplied to the shroud from the material supply mechanism is directed from shroud and into the fill tube, which is received in a bag such that its lower end forms a seal with the bottom of the bag. A fill tube plug is operatively coupled to the fill tube so as to selectively seal the upper end of the fill tube. The fill tube plug also has a vacuum line and an air line passed therethrough for the purpose of selectively introducing a vacuum or air into the interior of the fill tube. A support conveyor is positioned below and aligned with the bag filling tube. A bag filling spout is coupled to the lower end of the shroud and has a pair of gusset gripper mechanisms coupled thereto.

In operation, the fill tube is inserted into a bag held on an open spout such that the lower end of the fill tube will form a substantially air tight seal between the bottom of the bag and the lower end of the fill tube. Particulate materials are then introduced into the fill tube from the material supply mechanism through the shroud. The fill tube plug is next placed in the upper end of the fill tube and a vacuum is drawn within the fill tube. After a predetermined pressure has been reached or a particular dwell time has elapsed, the vacuum is cut off and atmospheric air is suddenly introduced into the fill tube to create an air hammer effect. The combination of the vacuum and air hammer act to density the particulate material within the bag. Optionally, the fill tube may be provided with a vibrating probe that extends downwardly through the fill tube and into the charge of particulate material placed in the bag. Activation of the probe further deaerates the particulate material.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a front elevational cross section of the densifying bag filling machine of the present invention; Figure 2 is the densifying bag filling machine of Figure 1 showing a bag addressed to the spout;

Figure 3 is the densifying bag filling machine of Figure 2 showing the fill tube in its fully extended position in the bottom of the bag;

Figure 4 is the densifying bag filling machine of Figure 2 showing the fill tube plug seated in the upper end of the fill tube;

Figure 5 is a close up of the upper end of the fill tube showing the fill tube plug in its retracted position;

Figure 6 is a close up of the upper end of the fill tube showing the fill tube plug seated in the upper end of the fill tube; and,

Figure 7 is a side elevational cross section of the densifying bag filling machine of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

Referring first to Figure 1 , the densifying bag filling machine 10 of the present invention can be seen to comprise a filling shroud 20 within which is reciprocally received a vacuum fill tube 30. The shroud 20 is supported by ring 22 that is itself adjustably supported by adjusters 24 from plate 26. Plate 26 may take many forms but is defined by its function, which is to provide a stable platform from which the shroud 20 may be suspended. The plate 26 is preferably secured to a framework (not shown). The framework is simply a support structure of the type commonly used with bag filling machines.

The densifying bag filling machine 10 described herein is specifically adapted for use in filling bags. However, the bag filling machine 10 may be readily adapted for filling other types of containers such as boxes, drums, bins, bulk bags, and others. In addition, the present invention may readily be adapted for use with bag sealing mechanisms that are capable of supporting and sealing bags and other containers at the location in which the bag is filled such as the device disclosed in US patent no. 5,771 ,667 to McGregor et al., hereby incorporated by reference. These types of bag sealing mechanisms can be arranged to move vertically or laterally. Alternatively, the present invention may be adapted for use with bag handling mechanisms constructed and arranged to transport filled bags from the bag filling machine 10 to a top-off and weighing station similar to that described in US patent no. 5,979,512 to McGregor et al., hereby incorporated by reference. It may also be desirable to provide an evacuation mechanism to remove air from a filled bag or container after the particulate material has been deposited within the container. Such an evacuation mechanism allows for what is commonly referred to as "vacuum packing". A suitable evacuation mechanism may comprise a snorkel-like tube that is inserted into a bag top prior to the bag's closure. A vacuum is drawn through the tube, the tube is removed from the bag, and the bag is sealed before the vacuum within the bag is compromised. The vacuum fill tube 30 is illustrated in its first, upper position in Figures 1 , 2 and 7 and in its second, lower position in Figures 3 and 4. Particulate material to be placed in a bag is fed into shroud 20 from a standard net weighing device (not shown) that is connected to shroud 20 by port 40. Note that this port 40 may connect to the shroud 20 at any suitable location. Preferably the port 40 will connect with the shroud 20 from the top of the shroud 20.

Figure 1 also illustrates a typical spout 50 which is connected by collar 52 to the lower end of shroud 20. Spout 50 may be a clamshell type of the type described in the aforementioned US patent no. 5,771 ,667, and may have a bag clamp (not shown) on the lower end of each of the respective clamshell halves of the spout 50. Where bag clamps are provided on the spout 50, they firmly grasp the upper edge of a bag B that has been addressed to the spout 50 by a bag supply mechanism (not shown). However, it is to be understood that the bag gusset handling mechanisms 60 disposed on either side of the spout 50 are sufficient to hold a bag B on the spout 50 for filling. Additional examples of a suitable spout 50 and also a bag gusset handling mechanism 60 are given in U.S. Patent No. 6,134,864 to McGregor et al., hereby incorporated by reference.

Where desired and where suitable, the bag spout 50 and gusset grippers 60 may be dramatically simplified. For instance, it is envisioned that the bag spout could in some embodiments consist of simple plates that may or may not have bag clamps coupled thereto rather than the more complicated clamshell halves described in the '864 patent. In addition, it is envisioned that in some embodiments gusset grippers 60 may be omitted. As can be appreciated from Figure 2, the spout 50 will be in its closed position when a bag B is first placed on the spout 50. If bag clamps (not shown) are provided on the spout 50, the bag clamps will grasp the bag B. Once the bag B has been addressed to the spout 50, the gusset grippers 60 will grasp the sides of the bag. The spout 50 then opens and the gusset grippers are simultaneously swung inward from their first, grasping position, to a second, open position so that the mouth of the bag may be fully opened by the spout 50. Note that the adjusters 24 that support the shroud 20 are adjustable in length to permit the shroud 20 and the spout 50 suspended thereunder to be moved up and down to accommodate bags B of varying height. In order to maintain an enclosed space within shroud 20, expandable shroud 21 is connected between shroud 20 and the plate 26. The expandable shroud 21 may be of an elastomeric material but is preferably a telescoping structure fashioned of the same material as is shroud 20.

In order to fully open the remainder of the bag B to facilitate the insertion of the fill tube 30 into the bag B, it may be desirable to inflate the bag B immediately prior to the insertion of the fill tube 30. Inflation of the bag B is accomplished by introducing a jet of air into the partially opened bag after the spout 50 and gusset gripping members 60 have moved to their open positions. Because the bag B is not held on the spout in an airtight manner, the inflation of the bag is accomplished by injecting a large quantity of high pressure air into the bag. While the high pressure air will escape the bag, the sudden inflow of a large volume of air will expand the bag and full open the bag along its full length. This allows the fill tube 30 to be inserted fully into the bag without catching the sides thereof. Inflation of the bag also permits the bag flaps to be more easily rotated into the bag. The high pressure air is introduced into the bag B through an air tube 36 that is coupled to a source of high pressure air such as a compressor.

Once the spout 50 has been opened, the vacuum fill tube 30 may be extended from its first, retracted position illustrated in Figures 1 ,2, and 7 to its second, extended position illustrated in Figures 3 and 5. In doing so, the lower end of the fill tube 30 presses against the fill conveyor 70 located directly beneath the densifying bag filling machine 10 as illustrated in Figure 3.

Figure 7 best illustrates how the fill tube 30 is raised and lowered. As can be seen, long cylinders 80 are secured at their bases to plate 26. The distal ends of shafts 81 of cylinders 80 have pulleys 82 secured thereto. Lines 84, which are preferably of braided wire or the like, are secured at one end to plate 26, pass over pulleys 82 and are secured at their other ends to plate 86. As the shafts 81 of cylinders 80 are extended, lines 84 passed over pulleys 82 raise plate 86. Similarly, as shafts 81 of cylinders 80 are retracted, lines 84 passed over pulleys 82 lower plate 86. Plate 86 is connected to the fill tube 30 by rods 87 and as plate 86 rises and falls, so too does the fill tube 30.

Preferably the surface of the conveyor 70 and the lower end of the fill tube 30 will have resilient materials applied thereto and will be supported resiliently such that when the fill tube 30 presses against the conveyor 70, a substantially air tight seal will be created. Note that the bag B will be captured between the lower end of fill tube 30 and the conveyor 70.

The upper end 31 of the fill tube is preferably funnel shaped and is formed so as to be complementary with the inner surface of the bottom of the shroud 20. When the fill tube 30 is in its fully extended position, the upper end 31 of the fill tube 30 will form a seal with the inner surface of the shroud 20 that will prevent the escape of particulate materials from the shroud 20 and which will also direct particulate materials into the bag B.

Once the fill tube 30 has been extended downwardly into the bag and has formed a substantially airtight seal between its lower end, the bottom of the bag B, and the conveyor 70, a charge of particulate material is fed through the port 40 into the shroud 20. As mentioned above, the charge of particulate material is preferably metered to a predetermined amount using a net weighing device or the like. The charge of particulate material is then tunneled down into the fill tube 30 by shroud 20. Note that the particulate material in the fill tube 30 is technically within the bag but is retained within the fill tube 30.

Once the entire charge of particulate material has passed into the fill tube 30, the shaft of cylinder 33 is extended to seat the inverted cone-shaped fill tube plug 32 into the funnel-like upper end of the fill tube 30. Cylinder 33 is connected between plate 86 and the fill tube plug 32. See Figures 4 and 6. Fill tube plug 32 is constructed and arranged to have an outer surface that is complementary with the inner surface of the top end of the fill tube 30. The inverted cone shape of the upper surface of the fill tube plug 32 is important in that particulate material flowing from the shroud 20 from the port 40 is not "dumped" directly into the fill tube 30. Such a violent filling manner would only serve to aerate the particulate material flowing into the fill tube 30. Therefore, the inverted cone shape of the fill tube plug 32 is useful in controlling the flow of the particulate material into the fill tube 30 so as to minimize the aeration of the particulate material and to prevent fines from floating about in the open space of the shroud 20 and fill tube 30. The fill tube plug 30 is also preferably fashioned of an elastomeric material or at least has an elastomeric coating or seal thereon that facilitates the formation of an air tight seal between the fill tube plug 32 and the inner surface of the tope end of the fill tube 30.

The fill tube plug 32 has a vacuum tube 34 and an air tube 36 passed therethrough such that the vacuum tube 34 and air tube 36 are in fluidic communication with the interior of the sealed space defined by the bag B, the fill tube 30, and the fill tube plug 32. The portions of the vacuum tube 34 and the air tube 36 illustrated in the Figures are also secured to the fill tube plug 32 and are constrained to move therewith. Flexible connections (not shown) are made from the valves 35, 37 to the respective supplies of negative and positive pressures. The vacuum tube 34 and air tube 36 are also passed through and slidingly guided by plate 86.

Once the fill tube plug 32 is firmly seated in the upper end of the fill tube 30, valve 35 connected in-line with the vacuum tube 34 is opened and a vacuum is drawn in the fill tube 30 through the vacuum tube 34. Vacuum tube 34 is connected to a standard vacuum source (not shown). The negative pressure of the vacuum drawn within the fill tube 30 removes air that is intermixed with the particulate material in the fill tube 30 and thereby densifies the particulate material.

The air that is removed by the vacuum tube 34 may contain particulate material that has become entrained in the air flowing out of the bag through the vacuum tube 34. In some instances it may be desirable to recapture this "lost" particulate material and redirect it back into the fill tube 30. In such cases, the vacuum tube 34 will be coupled to the shroud 20 in such a manner that particulate material removed from the bag may be returned to the shroud 20 and hence to the bag. One example of how this may be achieved is to couple a small cyclone (not shown) in line with the vacuum tube 34 so that the fines entrained with the air being removed from the bag B may be recovered by connecting the cyclone to the shroud 20. Even where it is not necessary to reintroduce the particulate material into the bag, it will most likely be desirable to recapture the particulate material for reuse or to simply prevent it from escaping into the atmosphere.

Once a sufficient vacuum has been drawn within the fill tube 30, the valve 35 controlling vacuum tube 34 is closed and a valve 37 in air supply tube 36 is rapidly opened to allow atmospheric air is to rush into fill tube 30. The rapid inrush of atmospheric air (or more simply, the application of a higher pressure) into fill tube 30 acts as an air hammer, thereby compacting the particulate material within the fill tube 30. The pressure wave created by the in rushing atmospheric air completes the densification process started by the removal of the air within the particulate material. More specifically, drawing a vacuum within the fill tube 30 removes air within the particulate material and densifies the particulate material to a degree and the inrushing atmospheric air then mechanically compacts the particulate material further. By combining these two steps, the particulate materials within a bag can be densified by up to 30% to 40%.

Where so desired, air supply tube 36 may be connected to a source of pressurized air (not shown) rather than to atmospheric air. In this manner the air hammer effect may be augmented and the pressurized air may also be used to partially inflate the bag immediately after it is suspended from the spout 50 as described above. Another feature of the present invention is a vibrating probe 15 that extends downwardly into the fill tube 30 from the fill tube plug 32. The vibrating probe 15 is preferably of the type that utilizes a rotating eccentric weight to induce vibrations therein. The probe 15 extends into fill tube 30 such that as a charge of particulate material is deposited into the fill tube 30 as it is inserted into bag B, the probe 15 will vibrate the particulate material, thereby further densifying the particulate material. Working in conjunction with the pulling of a vacuum and the application of the air- hammer effect, the probe 15 presents the opportunity to achieve greater densities in the particulate material.

Once the particulate material within the fill tube 30 has been densified, the fill tube plug 32 is retracted from the upper end 31 of the fill tube 30 by cylinder 33, and the fill tube 30 is retracted from the bag by the action of cylinders 80 as described above. As the fill tube 30 is retracted, the densified particulate material within the bag B flows to fill the bag B. After the fill tube 30 is fully retracted from the bag, the gusset gripper 60 swings outward to its first position and spout 50 closes the top of the bag. Note that as the fill tube is retracted from the bag, a slight vacuum preferably drawn through ports (not shown) at the lower end of the shroud 20. This is to remove any particulate material from the bag B that might be floating in the air within the head space of the bag B due to the removal of the fill tube 30 from the bag B. This step prevents the escape of particulate materials into the atmosphere. This is particularly important where the particulate materials comprise toxic, flammable, or irritating substances. Once the spout and gusset grippers 50 have closed the bag, 60 a transfer mechanism (not shown) grasps the now filled bag and removes it from the spout 50. The filled bag may be sealed in a sealing mechanism such as that described in the above identified US patent 5,771 ,667 that is vertically aligned with the densifying bag filling machine 10 or may be transferred to a stand alone sealing station (not shown). The mechanism for extending and retracting the fill tube 30 may vary from application to application and may include belt mechanisms, air cylinders, or worm gears.

When the volume of bags B to be filled varies, so too will the height of the bags B. Therefore, it may be necessary to modify the arrangement of the components of the densifying bag filling machine 10 of the present invention to account for the varying height of the bags to be filled. Small variations may be accommodated by constructing the cooperating surfaces of the upper end 31 of the fill tube 20 and the lower end of the shroud 20 to sealing mate over an extended range. For example, the upper end of the fill tube 30 may form a piston fit with the lower end of the shroud 20 and thereby direct particulate materials from the shroud 20 into the fill tube 30 over a given range of bag B sizes. At the same time, adjusters 24 may move the spout 50 and gusset grippers 60 up and down with respect to the location of the upper surface of the conveyor 70 to accommodate bags B of varying height. Similarly, the conveyor 70 may also be moved vertically with respect to the position of the spout 50 and gusset grippers 60.

Where the height of bags B varies beyond a certain range, it may be necessary to modify the length of the fill tube 30 itself to prevent the fill tube 30 from bottoming out in the bag B or to ensure that the fill tube 30 creates the proper seal at the bottom of a bag B in conjunction with the conveyor 70. The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

Claims

CLAIMSWhat is claimed is:

1. A densifying bag filling machine comprising:

a material supply mechanism;

a bag filling shroud having a lower, bag filling end and a port formed through the side thereof and secured to the material supply mechanism for receiving a particulate material from the material supply mechanism;

a bag filling tube located within the shroud and reciprocable by an actuator mechanism between an upper position and a lower position, an upper end of the bag filling tube have a funnel-like shape that is complementary with a correspondingly shaped lower, bag filling end of the shroud such that when the upper end of the bag filling tube is seated within the lower, bag filling end of the shroud, particulate material introduced into the shroud from the material supply mechanism is directed into the bag filling tube;

a fill tube plug constructed and arranged to selectively seal the upper end of the fill tube, the fill tube plug having a vacuum line and an air line passed therethrough for selectively introducing a vacuum and higher air pressures into the interior of the fill tube;

a support conveyor positioned below and aligned with the bag filling tube;

a bag filling spout coupled to the lower end of the shroud; and,

a pair of gusset gripper mechanisms coupled to the spout.

2. The densifying bag filling machine of claim 1 wherein the fill tube may be inserted through an open spout into a bag held on the spout such that the lower end of the fill tube will compress the bottom of the bag against the support conveyer, thereby forming a substantially air tight seal between the bottom of the bag and the lower end of the fill tube.

3. The densifying bag filling machine of claim 2 wherein a charge of particulate material is introduced into the fill tube when the fill tube has formed an air tight seal with the bottom of the bag, the fill tube plug being then inserted into the upper end of the fill tube before a vacuum is drawn in the fill tube through the vacuum tube passed through the fill tube plug.

4. The densifying bag filling machine of claim 3 wherein after the vacuum has been drawn within the fill tube, air at a pressure higher than that present within the fill tube is introduced into the fill tube through the air tube passed through the fill tube plug to produce an air-hammer effect on the particulate material deposited in the fill tube.

5. The densifying bag filling machine of claim 1 further comprising a vibrating mechanism disposed within the fill tube.

6. The densifying bag filling machine of claim 1 wherein the fill tube plug has an upper surface and a lower surface, the upper surface of the fill tube plug being generally that of an inverted cone, the lower surface being constructed and arranged to mate with a complementary surface of the upper surface of the upper end of the fill tube, the lower surface of the fill tube plug and the upper surface of the fill tube forming a substantially air tight seal therebetween when the fill tube plug is seated within the upper surface of the fill tube.

7. The densifying bag filling machine of claim 1 wherein the material supply mechanism is a net weighing device.

8. A method for simultaneously filling a container with a particulate material and densifying the material comprising the steps of:

supporting a container beneath a fill tube;

extending the fill tube into the container such that the distal end of the fill tube forms a substantially air tight seal with a bottom of the container;

depositing a charge of a particulate material within the fill tube;

sealing a top end of the fill tube;

drawing a vacuum within the fill tube containing the particulate material;

introducing air into the fill tube once the vacuum has reached a predetermined pressure level; and,

withdrawing the fill tube from within the container so as to leave the particulate material within the container. The method for simultaneously filling a container with a particulate material and densifying the material of claim 8, further comprising the step of activating a vibrating mechanism disposed within the fill tube to deaerate the particulate material.