WO2012034219A1

WO2012034219A1 - Automated displacing device for filling a bag

Info

Publication number: WO2012034219A1
Application number: PCT/CA2011/001034
Authority: WO
Inventors: Patrick Dumont; Yan GAGNÉ; Vital LÉVESQUE
Original assignee: Premier Tech Technologies Ltée
Priority date: 2010-09-13
Filing date: 2011-09-13
Publication date: 2012-03-22

Abstract

System comprising a single automated displacing device coupled with a bag gripper, continuously holding the bag, for filling a bag with solid bulk free flowing materials. The system displaces the bag between a pick-up location, a material filling point and an unloading location. The automated displacing device being programmed to displace the bag according to a trajectory associated to the following actions: a) take the empty bag at the pick-up location and position it at an outlet of the material filling device; b) maintain the bag in position during the product filling; c) transport the filled bag and release it to the unloading location; and d) optionally realize during the process other actions according to the type of equipment involved. The single automated displacing device carries out the sequence of actions throughout the filling step without transferring the bag and without releasing the upper portion of the bag.

Description

AUTOMATED DISPLACING DEVICE FOR FILLING A BAG

FIELD OF THE INVENTION The present invention relates to equipment for packaging solid bulk products in chemical and food industries just to name a few. More particularly, the present invention relates to a single automated displacing device for continuously holding the bag during the filling step. BACKGROUND OF THE INVENTION

Increasingly, in the packaging of solid bulk free flowing products such as powders or granules (chemical, organic or mineral) intended for the food and chemical industries to name a few, the requirements for quality bags are increasing more and more, in terms of the appearance of the bag as well as the compliance with strict standards, namely hygienic. Hereinbelow, it is understood that the term "bag" means "flexible container" which is made of polyethylene (PE), plastic coated woven polypropylene (PP), paper or other materials, with or without inner liner, and could also include Cap-Sac® (bag within a bag).

Usually, there are four major steps involved when packaging systems are used to bag solid bulk free flowing products: 1) forming/preparing, 2) filling, 3) closing/sealing and 4) evacuating the bag. The forming/preparing step, which is responsible for preparing the bag before the filling step, is more or less complicated according to the type of flexible containers used and the forming process involved (flat film, U film, tubular film or ready-made bags). The present invention mainly relates to the filling step which begins at an initial point (designated as a pick-up location); where the empty bag, previously delivered by the system carrying the forming/preparing step, is taken in charge for its filling (filling point); and finishes at a final point (designated as an unloading location) where the filled bag is delivered to the system carrying the closing/sealing step.

More specifically, the filling step includes various actions carried out by different modules or devices. Some of these actions, presented below, are optional and thus may not be required depending on the type of equipment involved.

• Taking the bag from the system carrying the forming/preparing step.

• Opening the bag.

• Transporting the bag to the material filling point.

· Supporting/maintaining the bag during the release of material; or gradually lowering the bag during the release of material in order to initially deposit the product at the bottom of the bag and then, at different levels in relation to the product level (bottom up filling).

Weighing the bag.

· Settling the product (contained into the bag).

Deaerating the bag.

Adding product (top up) to complete the filling of the bag and reach the desired quantity (target weight).

Transporting the bag towards the unloading location.

· Conforming the top of the bag (bringing together the walls of bag and restoring the upper part of the bag to return to its original shape).

Supporting/maintaining the bag during its closing/sealing.

Handing the bag to the unloading device, in a synchronized way.

In some bagging applications, the latter actions (deaeration, settling and adding product) can be performed at the closing/sealing step (following the unloading location). Other than potentially including these last actions, the third step always includes the closing and sealing of the bag. It should be noted that the latter may be effected by gluing, sewing, seaming, folding or a combination of these modes of sealing. Finally, during the evacuating step, the bag is exited through an outfeed device to palletizing equipment or other equipment.

Commonly, in existing equipment, actions taking place during the filling step give rise to various releases of the bag associated with the passage of an action to another performed by different transfer and handling components such as belts, straps, clips, grippers or conveyors. For example, in the case of an open-mouth bagger, up to four releases may be made depending on the number of modules in the bagger. More specifically, releases can take place at the following places: where the bag placer transfers the bag to the spout, where the spout transfers the bag to the transport unit, where the transport unit transfers the bag to the upper exit unit and where the upper exit unit transfers the bag to the sealing system.

During a transfer operation, the bag is physically handed over from one component to another, involving two distinct handling mechanisms. Each single transfer operation in the filling step increases the risk of a mishandling of the bag due to the transition of a mechanism to another. Such a situation creates quality problems such as misaligned bag closure, wrinkles, creases, etc. This situation can affect the appearance of the filled bag and can also increase problems of compliance with hygienic standards or others due namely to contamination. Indeed, bags may not be sealed tight, letting the air or external contaminants damaging the material in the bag and also resulting in product leaking from the bag. Furthermore, maintenance may be more difficult due to the fact that the equipment is complex considering the different transfer and handling components involved.

US 6955029 discloses a robotic system for packaging products. The robotic system opens the bag and places it horizontally with respect to a material filling unit. The horizontally filled bag can then be unloaded from the robotic system through a conveying system that carries away the bag from the filling point. Since the filling point and the unloading location are essentially at the same location, it would be difficult to add additional components at this location to carry out further processing of the bag between filling and unloading.

Indeed, by analysing the prior art, one can notice that since the first packaging machine of this type has been developed, specific modules or components have been progressively added to the baggers, adding complexity to packaging systems according to the degree of automation expected.

Therefore, there are presently needs for a system that avoids transferring the bag between dedicated components during the filling step, in order to meet the increasing bag quality requirements in terms of the appearance of the bag as well as the compliance with strict hygienic standards or others.

SUMMARY OF THE INVENTION

The present invention addresses at least one of the above-mentioned needs.

The present invention provides a single automated displacing device, such as a robot or a multi-axes programmable dedicated device, coupled with a multi-fonction end effector (named bag gripper) continuously holding the bag throughout the filling step, for filling a bag with solid bulk free flowing material. Said single automated displacing device being programmed to displace the bag according to a trajectory (between the pick-up location, the material filling point and the unloading location) associated to the following actions:

(a) take the empty bag at the pick-up location and position it at an outlet of the material filling device;

(b) maintain the bag in position during the product filling;

(c) transport the filled bag and release it to the unloading location; and

(d) optionally realize other actions during the process according to the type of equipment involved, such as deaeration, weighing, etc... Through these actions, the single automated displacing device is capable of continuously staying in control of the bag by never releasing the upper portion of the bag. This way, the bag never loses its desired shape, which results in a bag of very good quality. Moreover, the walls of bag may be brought together during the bag displacements (towards the material filling point and towards the unloading location) avoiding product contamination and dust generation, thus enhancing hygienic conditions.

Such a system can carry out all of these actions, that are accomplished by a conventional packaging equipment through separate distinct transfer and handling components, without releasing the bag during the filling process.

Preferably, the single automated displacing device is a programmable robot providing all displacements of the bag from the pick-up location up to the unloading location. Using a single programmable robot, that can bring the bag to every module, eliminates the need to transfer the bag from one mechanism to another. Furthermore, such a device can allow a significant reduction in the number of modules found in a conventional bagger. Indeed, for example, a weighing capability, using at least one load cell that sends a signal to the weigh controller which controls very accurately the filling of the bag and records the weight of the bag, can be added to the robot. This situation allows eliminating a distinct weighing module, thus resulting in a system that is less complex and easier to maintain. Considering that the robot is preferably suspended from the top, it makes the equipment even more hygienic since the floor is free, increasing cleaning access areas. Furthermore, robots are well known in the industry for their exceptional reliability (less downtime) and safety of operation. Finally, the use of a robot in the present invention makes it flexible to be suitable for different applications, different containers (for example: bags in a box or bag within a bag), different actions, different markets as well as different customer needs. In fact, the robot can be programmed to reach defined positions and thus vary the number of actions performed from one equipment to another.

The present invention is designed with the possibility of adding a second automated displacing device to gain speed. When using a plurality of automated displacing devices, the auxiliary modules, such as the bag dispensing device, material filling device and unloading device, may be shared between the automated displacing devices. The relative positioning of the modules is thus calculated to optimize production rates while avoiding trajectory collisions between the two automated displacing devices.

The present invention is also designed with the possibility of performing a bottom up filling process which consists in initially depositing the product at the bottom of the bag and then at gradually higher positions in the bag as a level of the product in the bag increases, in order to minimise dust emission and product expansion.

According to the present invention, there is also provided a method for packaging material in a bag, said bag having an open upper portion and a closed bottom portion, the method comprising the steps of:

a) gripping with a gripper the bag at a pick-up location;

b) displacing the gripped bag from the pick-up location to a material filling point;

c) maintaining the bag in position while the bag is filled by a material filling device;

d) displacing the filled bag to the unloading location; and

e) releasing the bag at the unloading location,

wherein the gripper is coupled to a single automated displacing device and continuously holds, without transferring and without releasing, the upper portion of the bag between the pick-up location and the unloading location, and wherein the unloading location is at a distance from the material filling point. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the invention will become apparent upon reading the detailed description, provided merely by way of non-limitative examples, and upon referring to the drawings in which:

Figure 1 is a perspective view of the system according to a preferred embodiment of the present invention, showing a robot acting as a single automated displacing device coupled with a bag gripper.

Figure 2 is a perspective view of the system according to a preferred embodiment of the present invention, with a robot acting as a single automated displacing device picking up an empty bag from the bag displacing device (at the pick-up location).

Figure 3 is a perspective view of the system shown in Figure 2, with the empty bag positioned under a material filling device. Figure 4 is a perspective view of the system shown in Figure 2, with the empty bag positioned up at the material filling device.

Figure 5 is a perspective view of the system shown in Figure 2, with the filled bag positioned under a deaeration lance.

Figure 6 is a perspective view of the system shown in Figure 2, with the filled bag positioned under a top-up station.

Figure 7 a perspective view of the system shown in Figure 2, with the filled bag delivered to a closing system (at the unloading position). Figure 8 is a perspective view of the system shown in Figure 2, with a filled bag at a closing system (at the unloading position) and the robot acting as a single automated displacing device picking up the next empty bag from the bag dispensing device (at the pick-up location).

Figure 9 is a perspective view of a system according to another preferred embodiment of the present invention, with two robots acting as automated displacing devices, the first robot positioning an empty bag under the material filling device, the second robot delivering a filled bag at a closing system (at the unloading position).

Figure 10 is a view of the system from a different perspective according to another preferred embodiment of the present invention, showing a multi-axes programmable dedicated device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in Figures 1 to 10, the present invention provides a single automated displacing device 12, preferably a robot 13 coupled with a bag gripper 24 continuously holding the bag, for filling a bag 18 with solid bulk free flowing material. The single automated displacing device 12 is programmed to displace the bag according to a trajectory (between the pick-up location 14, the material filling point 16 and the unloading location 20) associated to the following actions:

(a) take the empty bag 18 at the pick-up location 14 and position it at an outlet 42 of the material filling device (at filling point 6);

(b) maintain the bag in position during the product filling;

(c) transport the filled bag and release it to the unloading location 20; and

(d) optionally realize during the process other actions according to the type of equipment involved. Preferably, as shown in Figure 1 , the single automated displacing device 12 is a robot 13 coupled with a bag gripper 24, which comprises a weighing function using at least one load cell 26. Optionally, as shown in Figure 5, the process further may position the bag under a deaeration station or lance 30 for removing air from the bag.

As shown in Figure 2, the present invention provides a system 10 displacing the bag between a pick-up location 14, a material filling point 16 and an unloading location 20; where the transport of the bag in this system is done via the robot 3.

Preferably, the robot 13 is a 6-axis robot which assures all displacements of the bag 18 from the pick-up location 14 up to the unloading location 20. Preferably, the robot 13 is suspended from the top, making the system highly hygienic. The robot 13 is equipped with a bag gripper 24 which performs the following actions:

• take the empty bag 18 from the bag dispensing device 40 of the forming/preparing system (as seen in Figure 2),

• open the empty bag (as seen in Figure 3),

• maintain the bag in position during product filling (as seen in Figure 4) or perform the bottom up filling (which consists in initially depositing the product at the bottom of the bag and then at gradually higher positions in the bag as a level of the product in the bag increases),

• weigh the bag, at least one load cell 26 sends a signal to a weigh controller which controls very accurately the filling of the bag and records the weight of the bag, (optional action),

• conform the bag (optional action),

• Support/maintain the bag during its closing/sealing (optional action), and

• release the bag to the unloading location 20, preferably a bag exit device 43 with a closing station (as shown in Figure 7). As shown in Figure 8, with the closed bag at the unloading location 20, the robot 13 may return to the pick-up location 14 to pick up a next bag from the pick-up location 14.

The receiving of the bag at a pick-up location 14 may be done in a vertical, horizontal or any other configuration. The relative positioning and orientation of the robot 13 and other modules of the system 10 may differ from what is illustrated in the figures.

Preferably, as better shown in Figure 6, the system 10 may further comprise a top- up station 50 to further fill up the bag after deaeration and before closure thereof.

Figure 9 shows a system according to another configuration, with two automated displacing devices, the first automated displacing device 12A positioning a bag under the material filling device at the material filling point 16, the second automated displacing device 12B positioning a filled bag at the unloading location 20.

In cases where a simpler or less expensive configuration is considered, Figure 10 shows a system according to another configuration, with a multi-axes programmable dedicated device.

As mentioned above, the present invention addresses the needs of the food industry, as it can deal with quality bags. It can properly close bags through proper alignment and by avoiding incorrect folds. It can also provide tightly sealed closures to avoid air penetration or products leaking from the bag.

The present system can also help a packaging system meet strict legal and voluntary hygienic standards, through easily accessible finished surfaces and cleaning areas while facilitating inspection thereof. The present system also addresses the various needs of operators and plant managers of packaging systems as it provides a system that is easy to operate, easy to maintain, reliable and efficient.

The present system offers the following additional advantages:

-improved reliability since a smaller number of modules or components results in a smaller number of possible failures, and as robots can typically operate several tens of thousands of hours before requiring a major maintenance overhaul;

-improved efficiency since the robot moves precisely and allows reduction the amount of bag releases between different modules via different dedicated mechanisms; the reduction in the amount of releases reduces the number of bags being rejected through errors during transfers and improves the overall quality of the filled bags being produced;

-increased hygienic aspect since it is a simplified system comprising a smaller number of components and modules in some cases, thus facilitating maintenance and cleaning; and

-improved flexibility for changes in the operation of packaging systems; since the robot is programmable, operation positions or movements of the robot can be modified from one packaging equipment to another in order to operate in varying conditions.

Although preferred embodiments of the present invention have been described in detail herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to these precise embodiments and that various changes and modifications may be effected therein without departing from the scope or spirit of the present invention.

Claims

1. A system for equipment packaging material in a bag, said bag having an open upper portion and a closed bottom portion, said system comprising a single automated displacing device coupled to a gripper, being displaceable between a pick-up location and an unloading location, said single automated displacing device being programmed to control displacement and operation of the gripper to:

a) grip the bag at the pick-up location;

b) displace the gripped bag from the pick-up location to the material filling point;

c) maintain the bag in position while the bag is filled by the material filling device;

d) displace the filled bag to the unloading location; and

e) release the bag at the unloading location,

said single automated displacing device being further configured to control operation of the gripper to continuously hold, without transferring and without releasing, the upper portion of the bag between the pick-up location and the unloading location, wherein the unloading location is at a distance from the material filling point.

2. The system according to claim 1 , wherein the single automated displacing device is a multi-axis robot.

3. The system according to claim 2, wherein the multi-axis robot is a 6-axis robot.

4. The system according to claim 1 , wherein the single automated displacing device is a multi-axis dedicated device.

5. The system according to any one of claims 1 to 4, wherein the single automated displacing device is further programmed to gradually lower the bag during release of material in order to initially deposit the product at a bottom of the bag, and then at gradually higher positions in the bag as a level of the product in the bag increases.

6. The system according to any one of claims 1 to 5, wherein the single automated displacing device is further programmed to displace the bag to a deaeration station.

7. The system according to any one of claims 1 to 6, wherein the single automated displacing device is further programmed to displace the bag to a top-up station.

8. The system according to any one of claims 1 to 7, wherein the single automated displacing device is further programmed to weigh the bag through the gripper comprising at least one loadcell.

9. The system according to claim 2 or 3, wherein the robot is a suspended robot.

10. The system according to claim 2 or 3, wherein the robot is a first robot and further comprising a second robot operating in parallel with the first robot.

11. A method for packaging material in a bag, said bag having an open upper portion and a closed bottom portion, the method comprising the steps of:

a) gripping with a gripper the bag at a pick-up location;

d) displacing the filled bag to an unloading location; and

e) releasing the bag at the unloading location, wherein the gripper is coupled to a single automated displacing device and continuously holds, without transferring and without releasing, the upper portion of the bag between the pick-up location and the unloading location, and wherein the unloading location is at a distance from the material filling point.

12. The method according to claim 11 , wherein the single automated displacing device is a multi-axis robot.

13. The method according to claim 12, wherein the multi-axis robot is a 6-axis robot.

14. The method according to claim 11 , wherein the single automated displacing device is a multi-axis dedicated device.

15. The method according to any one of claims 11 to 14, wherein step c) further comprises a step of gradually lowering the bag during release of material in order to initially deposit the product at a bottom of the bag, and then at gradually higher positions in the bag as a level of the product in the bag increases.

16. The method according to any one of claims 11 to 15, further comprising a step, between steps c) and d), of displacing the bag to a deaeration station.

17. The method according to any one of claims 11 to 16, further comprising a step, between steps c) and d), of displacing the bag to a top-up station.

18. The method according to any one of claims 11 to 17, further comprising a step, between steps c) and d), of weighing the bag, wherein the single automated displacing device is coupled to a gripper comprising at least one loadcell.

19. The method according to claim 12 or 13, wherein the robot is a suspended robot.

20. The method according to claim 2 or 3, wherein the robot is a first robot and further comprising a second robot operating in parallel with the first robot.