Apparatus and method for filling big bags Specification
The present invention relates to an apparatus and a method for filling big bags and in particular for filling FIBC big bags with at least one bulk material and in particular a lightweight bulk material.
A big bag is a flexible bulk material container the internationally common short designation of which is FIBC which is an abbreviation of "Flexible Intermediate Bag Con- tainer".
These big bags may consist for example of woven plastic such as polypropylene and hold volumes of up to 1000 or even 4000 liters or more.
Most big bags cover the surface of a Europallet and when filled they may show heights of up to ca. 2.2 m or more.
The present invention in particular concerns the filling of lightweight and ultralight materials into these big bags.
For example or preferably, silicate or carbon black or similar lightweight materials for a great variety of different appli- cations may be filled into these big bags.
A bag completely filled with these materials may show a height of up to 2.40 m and up to 150 kg weight.
The bulk densities of the bulk mate- rials are preferably less than or equal to 0.25 kg per cubic decimeter.
Efficiently bagging these materials is complex since their air content is very high.
In the prior art, apparatuses and methods have been disclosed for filling these lightweight materials into conventional small bags showing filled weights of 10 kg.
For filling these kinds of still manageable bags it has been disclosed to apply pressure jaws to the bag side walls from outside so as to reduce the available volume and thus to faster obtain a higher internal pressure during filling resulting in better deaeration through the bag walls.
In the case of conventional small bags this allows to increase the filling rate.
Alternatively it has also been disclosed to bag lightweight materials by means of a so- called vacuum packer where the entire package is placed in a vacuum chamber and the intended fill of bulk material is sucked into the bag.
Although these methods work reliably, they call for complicated apparatus already for bagging bulk materials into conventional bags of for example 10 kg filled weight.
These methods are not suitable for filling lightweight bulk materials into big bags since the required apparatus and also the costs would be too large and too high respectively.
US 2015/0175280 Al discloses an apparatus and a method for compacting bulk materials in a big bag, wherein a big bag containing materials intended for compacting is positioned on a base, and a pressing plate is lowered from above.
Vibration elements generate pressure to compact the bulk materials.
US 4 718 464 A forms the basis for the introductory portion of claim 1 and discloses an apparatus for automatically filling and weighing big bags.
The bottom bag end can be supported by a base support showing an extendible central plate, and a plate which is bent down outwardly at an angle.
Filling bulk materials into big bags is very complex since a great deal of manual labor is reguired.
Specifically for bag- ging lightweight materials, coated bag materials are used which show poor or nearly non-existent deaeration through the outer walls.
This is why bagging is moreover very time- and work- consuming since an operator must start and continuously control the filling process so as to avoid inadmissible excess pressure building up in the big bag.
Furthermore the operator must control the filling process so that the filled quantity fits in the big bag.
This requires the permanent presence of an operator which considerably increases the bagging costs.
It is therefore the object of the present invention to provide an apparatus and a method with which to also efficiently fill lightweight bulk materials into big bags.
This object is solved by an apparatus having the features of claim 1 and by a method having the features of claim 12. Pre- ferred specific embodiments of the invention are the subjects of the subclaims.
Further advantages and features of the pre- sent invention can be taken from the general description and the description of the exemplary embodiments.
An apparatus according to the invention for filling big bags and in particular FIBC big bags with at least one bulk material and in particular a lightweight bulk material comprises a frame structure, at least one filling spout for filling the big bag,
a weighing unit, and at least one compacting device.
The frame structure is provided with respectively receives a holding de- vice having multiple holding hooks to receive holding loops of a big bag to be filled and to retain the big bag during the filling process.
A supporting device is provided which defines a supporting surface which supports the bottom end of the big bag from beneath.
Assigned to the supporting device is a com- pensating device having an active unit that is shiftable rela- tive to the supporting surface to act upon the bottom end of the big bag by means of the active unit.
The compacting device further comprises a head plate device that is provided for acting upon the big bag from above, and wherein the head plate device is in particular height-adjustably attached to the frame structure for applying pressure onto the big bag from above as required, and wherein at least one sensor is disposed at the head plate device for capturing a measure of a pressing force.
The apparatus according to the invention has many advantages.
A considerable advantage of the apparatus according to the invention consists in the fact that the big bag can be supported by the supporting surface of the supporting device and it may for example be put down thereon and then the active unit of the compensating device can be shifted relative to the supporting surface to act upon the bottom end of the big bag.
This allows in particular to reduce bulging of the bottom end of the big bag.
Thus the apparatus is in particular suitable for filling lightweight bulk materials into big bags showing poor deaeration and/or coating, in particular plastic coating.
Plastic-coated big bags deaerate poorly or not at all through the outer wall so that additional measures to increase deaera- tion show advantageous effects on the filling rate.
Preferably the supporting surface of the supporting device (temporarily) bears fully against the bottom end of the big bag intended for filling or the filled big bag.
Preferably the big bag hangs at least temporarily and in particular substantially freely from the holding loops during the filling process and the weighing unit serves for weighing during filling.
Filling is preferably done by a gross weighing procedure.
Gross weigh- ing procedure means that the big bag and parts of the filling device are weighed as well.
In all the configurations it is preferred for the big bag to show a top filling mouth while the filling spout shows a down- wardly filling opening.
The filling spout shows a longitudinal extension and a product stream is substantially oriented down- wardly parallel to the longitudinal extension of the filling spout so that the bulk material enters the filling mouth of the big bag through the filling opening from above to below.
The filling opening is substantially or entirely oriented in the vertical. 5 Preferably a support frame is provided for receiving the hold- ing device and/or the holding hooks.
Preferably the support frame is carried by weighing cells and supported on the frame structure.
The supporting device comprises in particular an extending or at least one extending pressing organ which is displaceable from a rest position to an acting position to reduce any bulging of the bottom of a filled big bag.
In a preferred embodiment the active unit of the compensating device is shiftable between a lower rest position and an upper acting position.
Preferably the active unit is automatically traversable by way of a lifting drive between the lower rest position and the upper acting position.
Particularly preferably the compensating device is attached to the supporting device.
This allows a simple structure and sim- ple operation.
The supporting device may in particular be a component or a separate unit separate from the frame structure which is preferably mounted, set up, or attached beneath the filling spout.
It is also possible for the supporting device to be configured as a separate modular unit which is then mounted, set up, or attached relative to the supporting device.
The compensating device may for example be a separate modular unit attached to the floor or a ceiling of a building.
Other attachment options are likewise possible.
It is preferred for the compensating device to be disposed such that the active unit acts upon the bag bottom in a central region of the supporting surface of the supporting device.
The active unit is disposed in a central region of the supporting surface in particular in the top acting position.
In the rest position the active unit may for example also be disposed off- center or in particular also sunk in the supporting device.
Preferably the supporting device and the compensating device are configured and disposed so that the active unit acts upon the bag bottom from beneath in a central region of the support- ing surface of the supporting device while the compensating device is located in the acting position.
Advantageously the supporting device is displaceable from a lower home position to an upper support position.
In these configurations the supporting device is part of the compacting device.
Then the support position may be referred to as the compacting position.
The compacting device comprises at least one head plate device which is provided for acting upon the big bag from above.
Particularly preferably the compacting device comprises the supporting device and the head plate device with the supporting device acting upon the big bag bottom from beneath and the head plate device acting upon the big bag from above to support deaeration and to achieve compacting of the bulk material filled into the big bag.
Preferably the head plate device is height-adjustably attached to the frame structure in particular for applying pressure onto the big bag from above as reguired.
It is particularly preferred for the filling spout to pass through the head plate device and/or for the head plate device to surround the filling spout at least partially and in particular substantially completely or completely in the radial direction.
The head plate device may be configured as a continuous plate showing for example in a central region a hole for the filling spout to pass through. Or else it is possible for the head plate device to not show a solid plate but struts, rods, or other means allowing to apply pressure onto the big bag. Preferably at least one pressure sensor is assigned to the filling spout. Or else it is possible to provide 2 or more pressure sensors for example to increase outage safety. In preferred specific embodiments at least one sensor for cap- turing a measure of a pressing force is disposed at the head plate device or some other component of the apparatus. Advan- tageously at least one sensor may be disposed at the supporting device for capturing a measure of the pressing force. This sensor may for example be configured as a force sensor or a pressure sensor. It is also possible to provide a current sen-
sor. The sensor enables in particular force , pressure , or current-controlled pressing of the compacting device. In preferred specific embodiments the filling spout shows at least one double-walled section, the inner wall of the double- walled section consisting at least partially of an air-permea- ble wall material. In all the configurations it is preferred for the filling spout to have at least one deaeration device assigned to it to carry off air exiting the bag. Preferably the filling spout and the holding device and in particular also the head plate device are received on a support frame which is weighed by means of the weighing unit. This enables a gross weighing procedure to precisely obtain the intended filled weight.
In advantageous specific embodiments the filling spout has a deaeration device with at least one bleed line assigned to it which is decoupled from the frame structure through at least one compensator.
The deaeration device is preferably connected with the filling spout so as to efficiently evacuate the air exiting the big bag upwardly through the filling spout.
In a preferred specific embodiment the bleed line comprises 2 lock valves spaced apart from one another between which the compensator 1s disposed.
Particularly preferably the lock valves are operated separately.
A sampler is preferably dis- posed between the lock valves.
Operating the lock valves thus allows to take samples from the ongoing filling process easily and efficiently.
Another operating position allows effective deaeration.
In all the configurations a product feed line or at least one product feed line is preferably provided.
In all the configu- rations it is particularly preferred to provide 2 different product feed lines and product feed paths.
Then preferably at least 2 conveyor elements are provided, each product feed line comprising at least one conveyor element.
In all the configu- rations it is possible for each product feed to comprise 2 or more conveyor elements.
Preferably at least one conveyor element is provided which is connected with a product feed through a product feed line.
The conveyor element may in particular be carried by the support frame so that the conveyor element is part of the weighed system.
In advantageous specific embodiments a flexible compensator is part of the product feed line and is disposed between the stationary part of the product feed line and a weighed part of the product feed line to achieve decoupling of weights during a weighing operation.
This allows to considerably improve the weight accuracy.
Preferably the flexible compensator has an aeration valve as- signed to it to enable air compensation in the product feed line preceding a weighing operation.
This is particularly ad- vantageous since the air compensation helps to maintain the flexibility of the flexible compensator.
It has been found that a flexible hose may become highly rigid if the flexible com- pensator contains compacted bulk material.
Then the rigidity even of a flexible compensator may increase to such a degree as to produce incorrect weight measurements.
Employing an aer- ation valve which allows ease of air compensation or giving off air blasts into the product feed line provides considerably increased precision of the weighing operations and thus preci- sion of filling.
It has been shown that this measure may con- siderably increase the level of precision of automatic filling so that such measure made it possible to achieve or decrease the conventional threshold values of (manual) filling accuracy.
In all the configurations it is particularly preferred for at least one diaphragm pump to serve as the conveyor element for feeding the intended bulk material into the big bag.
Other conveyor elements may be used depending on the type of bulk material.
Preferably the supporting device is vertically adjustable.
The supporting device may comprise a floor table or a roller track with the rollers of the roller track provided with a drive to be driven as required.
The head plate device may show one single head plate or else multiple head plates which together form the head plate device.
The head plate device may be configured as a mold plate to shape the upper region of the big bag as desired following a high speed flow and/or following the filling process and/or periodically.
A pressure sensor assigned to the filling spout may be provided inside the filling spout or else for example in a line leading up to the filling spout.
It is also possible to dispose the pressure sensor in a region protruding into the big bag.
A force sensor at the supporting device and/or at the head plate device is advantageous since it allows to obtain a measure for loads acting upon the big bag during the filling process.
This allows to reliably avoid too high loads on the big bag resulting from the internal pressure so as to considerably decrease the risk of breakage and frequency of breakage.
In the case of a double-walled section at the filling spout whose inner wall consists at least partially of an air-permea- ble wall material it may in particular comprise a wire mesh or consist of a wire mesh.
Comparable materials are likewise pos- sible.
The mesh size of an air-permeable wall material is in particular such that air may exit while bulk material is at least substantially retained.
The method according to the invention serves to fill bulk ma- terial into big bags and in particular to fill bulk material into FIBC big bags wherein a big bag is hung by its holding loops from the holding hooks of the holding device of an appa- ratus for filling.
The holding hooks retain the big bag at least temporarily during the filling process.
The big bag is positioned on the supporting surface of a supporting device at least after the filling process.
An active unit of a compen- sating device is displaced upwardly relative to the supporting surface of the supporting device so as to act (only) upon part of the bottom surface of the big bag.
This also allows to reduce any bulging of the bottom end of the big bag by way of acting provided in particular in spots and preferably in the region of the highest bulging effect.
Then, at least one measure of the force acting upon the big bag is captured by a height-
adjustable head plate device.
The method according to the invention also has many advantages.
The method allows efficiency of filling lightweight bulk mate- rials into poorly deaerating big bags providing high weight accuracy even with automatic or semiautomatic filling.
The big bag is preferably alternatingly filled up to a prede-
termined pressure and then compressed.
The big bag is prefera- bly compressed from beneath by means of a supporting device pressing against the big bag bottom while pressure is also applied on the big bag from above.
It is preferred to measure a pressure during filling that is characteristic of the internal pressure in the big bag.
This allows pressure-controlled filling that is controlled automat- ically in particular by means of a control device so that the maximum internal pressure permissible for the big bag is not exceeded so as to avoid damage.
The supporting device preferably presses against the big bag bottom from beneath for compacting the bulk material.
Pressure on the big bag is preferably applied from above for compacting the bulk material.
According to the invention, at least one measure of the force acting upon the big bag by the head plate device is captured.
Advantageously, at least one measure of the force acting upon the big bag by the supporting device is captured.
This allows to ensure efficiency of compacting and/or to avoid damaging the big bag by way of operating the compacting device preferably at close to the maximum force permitted and retaining the high- est inner bag pressure within the permissible range so as to minimize the deaerating time.
In advantageous specific embodiments the big bag weight is measured with a weighing unit.
The following process steps are preferably repeated in a loop until the actual weight lies within a tolerance range around the target weight: = Firstly the conveyor element is operated for filling bulk material into the big bag. = Thereafter the bulk material is compacted by having the compacting device exert pressure on the big bag bottom from beneath and/or the head plate device, against the bag from above. - Then the supporting device and/or the head plate de- vice is retracted so that the big bag hangs (freely) from the holding hooks. - The big bag is weighed. = At least near the end of the filling process the active unit of the compensating device is displaced upwardly relative to the supporting surface of the supporting device to act upon part of the big bag bottom surface.
This occurs in particular when the supporting device bears against the big bag bottom with its supporting surface.
Extending the active unit reduces any bulging of the big bag bottom which does not automatically recede due to the low weight of the product itself as the big bag is placed on the supporting device.
In this way the content of the big bag is effectively compacted once again so as to enable a significantly higher bulk material compactness overall and to obtain a nearly planar contact area for the later transport.
The weight of the big bag is preferably weighed after compacting the bulk material in the big bag.
A conveyor element disposed on the non-weighed part allows considerable reduction of con- ceivable errors in the weighing operation by way of such com- paction.
Absent such prior compaction the material present in the filling spout might still exert force on the weighing cell or weighing cells or on the entire weighing unit which might involve considerable adulteration of the measured actual weight.
The compaction clears volume in the head space of the big bag into which the product present in the filling duct can descent.
Thus the weighing unit is relieved from interfering influence of forces and the actual weight can be more reliably determined.
The loop indicated above may be left for example if it is clear that the pumping conveyor element will obtain the desired tar- get weight by way of a number of strokes determined from the weight difference between the target weight and the actual weight.
To this end the weight previously conveyed per pump stroke is determined.
This enables a high precision configura- tion of the apparatus optionally with calibration capability.
The method described above is in particular suitable for fill- ing coated big bags or big bags showing poor deaeration capac- ities.
In all the configurations it is preferred to suck off or remove air at least temporarily during, prior to, or after the filling process.
Air may for example be removed or sucked off from the big bag interior for example through a double-walled filling spout to ensure effective and optionally actively assisted de- aeration.
The invention allows to automatically fill lightweight materi- als into big bags.
Manually controlling the filling process is not necessary.
A variety of bags and bag types may be filled successively.
Further advantages and features of the present invention can be taken from the exemplary embodiment which will be discussed below with reference to the enclosed figures.
The figures show in: Figure 1 a side view of an apparatus for filling big bags in a first position; Figure 2 a side view of the apparatus according to Figure 1 in a second position; Figure 3 a side view of the apparatus according to Figure 1 in a third position; Figure 4 a side view of the apparatus according to Figure 1 in a fourth position;
Figure 5 the region of the filling spout of the apparatus ac- cording to Figure 1 in an enlarged illustration;
Figure 6 the region of the conveyor element of the apparatus according to Figure 1 in an enlarged illustration; Figure 7 the region of the filling spout with the deaeration device of the apparatus according to Figure 1; and Figure 8 a schematic plan view of the supporting device and a weighing table for the apparatus according to Figure 1. Figure 1 schematically illustrates an apparatus 1 according to the invention for filling bulk materials 2 into big bags 10. The apparatus 1 comprises a frame structure 3 in the shape of a frame or the like to which further components of the apparatus I are mounted.
Beneath the filling spout 4 a supporting device 40 is set up, attached or mounted on the floor, which serves to support a filled big bag and also forms part of a compacting device 6 by means of which a partially filled big bag 10 is compacted once or multiple times during the filling process.
The big bag 10 is hung by its holding loops 11 from holding hooks 8 of a holding device 7 while the filling valve 10b is connected with the filling spout 4 for example via a quick release (may be incorporated) at least substantially dustproof.
During the majority of the filling process the big bag 10 is hanging freely from the loops 11. The supporting device 40 with the supporting surface 41 is located clearly below the bag bottom 12. When bagging lightweight materials with a considerable air con- tent entering the big bag along with the bulk material, the big bag inflates and the bottom of the big bag 10 bulges outwardly.
Figure 1 illustrates this state.
The apparatus 1 comprises a compacting device, presently sub- stantially consisting of the supporting device 40 and the head plate device 16. For compacting, the supporting device 40 or the supporting surface 41 may be adjusted upwardly while the head plate device 16 is displaced downwardly via the cylinders 47 so that pressure is applied to the big bag 10 simultaneously from above and below, thus improving deaeration.
Here the supporting device 40 comprises a roller track with rollers 42 which on the whole define or span a supporting surface 41. During compaction the supporting surface 41 sub- stantially bears fully against the bag bottom 12. The supporting device 40 comprises an adjustment frame 45 re- spectively a cross bar which serves for height adjustment of the supporting surface 41.
The compensating device 30 is disposed and accommodated cen- tered on the supporting device 40. Here the compensating device 30 is attached to the supporting device 40 so that the compen- sating device 30 is displaced along during height adjustment of the supporting device 40. Or else it is possible to dispose or attach the compensating device 30 separately on, respec- tively to, the floor so that during height adjustment of the supporting device 40 there is no height adjustment of the com- pensating device 30 respectively the active unit 31 of the compensating device 30. The compensating device 30 comprises the active unit 31 which is configured height-adjustable here.
The active unit 31 acts as a pressing member and shows an active surface 3la (see Figure
2). Figure 1 illustrates the home position 43 of the supporting device 40 and the idle position 33 of the compensating device
30. After filling the big bag 10 firstly for example far enough to obtain the shape illustrated in Figure 1, the supporting device 40 with the supporting surface 41 is height-adjusted so that the supporting surface 41 fully bears against the bottom end 12 of the big bag 10. Simultaneously the cylinders 47 are extended from above so that the head plate device 16 is lowered, bearing against the head region of the big bag. Now the com- pacting device 6 with the head plate device 16 and the support- ing device 40 press on the big bag 10 from above and beneath so as to provide effective deaeration of the bulk material and volume reduction. Thereafter the supporting device 40 may be lowered once again and the head plate device 16 raised, whereupon the conveyor element 9 (see Figure 5) can be restarted and further bulk material can be filled into the big bag 10. Now bulk material 2 is filled into the big bag 10 and the compacting device 6 compresses the big bag 10 alternatingly. In each compression or in some single compressions in particu- lar near the end of the filling process, in addition to com- pressing, the compensating device 30 may be activated and the active unit 31 extended via the lifting drive 35 as it is illustrated in Figure 2. To this end the active unit 31 is displaced upwardly relative to the supporting surface 41 so that the active unit 31 virtually dips into the bottom of the big bag 10, additionally compressing the bag bottom 12 on the considerably smaller active surface 3la. Figure 2 shows the acting position 34 while Figure 1 illustrates the idle position
33. It has been surprisingly found that the additional action of the active unit 31 can achieve considerable improvement to filling. The additional compression in the region of the bag bottom 12 near the end of the filling process allows to achieve considerably improved weight accuracy. It is possible that the additional compression releases material in the head region of the big bag 10 so as to achieve a better decoupling for the weight measured. Moreover the stability of the big bag after the filling process is improved. Figure 3 shows a position after returning the active unit 31 back to the idle position 33 and after returning the supporting device 40 to the home position 43 and lifting the head plate device 16 back up via the cylinders 47. In this position the big bag 10 is once again hanging freely from the hooks 8 by its loops 11. The bag bottom 12 bulges outwardly to a far lesser degree than before pressing and before the action of the active unit 31. The active unit 31 acts upon a considerably smaller surface 3la than does the supporting surface 41 by means of which the bag bottom 12 rests on the supporting device 40. Preferably the surface ratio be- tween the active surface 3la and the cross-sectional area of a big bag 10 lies between about 1:20 and 1:4. Figure 4 shows another position of the apparatus 1 in which a pallet 55 has been placed on the roller track or the supporting device 40 and the filled big bag 10 was lowered onto the pallet so that the bag bottom 12 bears against the pallet 55 with its standing surface 10a. The filling valve 10b and the holding loops 11 were removed from the filling spout 4 or the holding hooks 8 respectively so that the big bag 10 now stands freely on the plate 55. Figure 5 shows an enlarged illustration of the region of the filling spout 4, with two different conveyor elements 9 and product feed lines 28 drawn on the left and the right, for example to allow ease of filling two different products involv- ing a minimum of conversion steps.
The adjusting flap 48 is shifted for converting the product travel paths.
Little clean- ing work is involved.
Figure 5 shows that both the conveyor elements 9 and also the filling spout 4 and the holding device 7 with the holding hooks 8 are received on and attached to a support frame 19 which is supported on the frame structure 3 by way of weighing cells 15. Thus, in this configuration the one or more conveyor element (s) 9, the filling spout 4, the holding device 7 with the holding hooks 8 and also the support frame 19 form part of the weighed system.
The pertaining weight is taken into account (tared) in the weighing operation so as to allow conclusions about the weight filled into the big bag 10. As Fig. 5a shows, the filling spout 36, which is double-walled, comprises in at least one section an air-permeable screen 38 or wire mesh or the like so that air is removed while the bulk material to be filled is retained.
Figure 6 shows an enlarged illustration of the conveyor element 9 configured as a diaphragm pump with the product feed 39 and the product feed line 28. The product feed 39 comes from the silo and is for example attached to the frame structure 3 and thus it does not form part of the weighed system.
A stationary part 28a of the product feed line 28 may extend further from the frame structure.
By means of a compensator 29 the stationary part 28a is decoupled weight-wise from the conveyor element 9 and the weighed part 28b of the product feed line 28. The compensator may consist of a flexible and/or elastic tubular material or the like so as to enable decoupling from the frame structure to the weighing part. However, it has been found that even lightweight products may show such a compaction of the bulk material within the compensator 29 that the compensator 29 cannot fully ensure its function. Therefore at least one aeration valve 14 is assigned to the compensator 29 to allow air compensation prior to a weighing operation. The presently employed diaphragm pump 9 and the presently il- lustrated exemplary embodiment show the compensator 29 on the suction side of the diaphragm pump 9. It may optionally be sufficient to open the aeration valve 14 so that ambient air can be led into the compensator from outside. In this and other configurations it is also possible to actively supply air through the aeration valve 14 prior to a weighing operation. It has been found that air compensation or an active air blast through the aeration valve 14 considerably increases the flex- ibility of the flexible condensator 29 so as to allow reliable and reproducible weight measurement. Figure 7 shows an enlarged illustration of the region of the filling spout 4 illustrating the deaeration device 20 via which any surplus air can be outlet from the filling spout interior. The deaeration device 20 allows to feed the outlet air through the bleed line 21 for example to a dust-removing device. The deaeration device allows efficiently outletting any surplus air. This deaeration device is provided with two lock valves 25, 26 disposed spaced apart from one another. The lock valve 26 is presently connected with the filling spout 4 while the lock valve 25 is connected with the frame structure. Disposed between the lock valves 25 and 26 is a flexible compensator 22 which allows weight-wise decoupling.
As a rule, no aeration valve needs to be provided since the bleed line 21 will as a rule not contain any compacted bulk material.
Between the two separately operated lock valves 25 and 26, a sampler 27 is provided to which suitable sampler vessels or sampler lines may be connected.
Optionally a third shiftable valve may be provided.
Figure 7 also shows in broken lines the pressure sensor 17 which is disposed within the filling spout 4 via which a measure for the internal pressure in the big bag 10 can be captured.
Figure 8 finally shows a plan view of a supporting device 40 for the apparatus 1 according to Figure 1 and adjacent thereto, a separate weighing table 50, wherein presently both the sup- porting device 40 and the weighing table 50 show rollers 42 each provided for controlled operation by means of a drive 42a or 52a.
The drives 42a and 52a shown rotate in both rotational directions.
Another structure may dispense with drives rotating in both rotational directions.
It is possible to convey a pallet 55 firstly for example onto the weighing table to read the unloaded weight of the pallet.
At a suitable time during the filling process the pallet 55 may be displaced back onto the supporting device 40 to place the big bag 10 thereon.
Alternatively the pallet may be weighed on the weighing table after filling together with the big bag to obtain the total weight.
Thus, when loading these big bags for example on trucks or other transportation means is intended both cases provide for computing the effectively acting total weight already during filling and the big bag may then be labeled.
In all the configurations and exemplary embodiments it is pos- sible and preferred to alternatingly fill and compact for ex- ample 3, 4, 5 or 6 times during a filling process. In one pressing, for example pressure may be applied onto the bag for to 40 seconds and preferably about 20 seconds to achieve effective deaeration. The times depend for example on the prod-
uct. If the big bag is compacted for example three or four times, it is possible to extend the active unit of the compen- sating device only during the last compaction or the last two 10 compactions. With an increasing number of pressings per filling the degree of compaction increases so that less volume is re- leased step by step. A completely filled bag filled with lightweight materials may reach weights of 150 kg or 200 kg. With heavier materials, filled weights of up to 2 t are possible. In all the configurations it is preferred to use sewn bags with corner tabs with the corner tabs disposed inwardly, thus provid- ing for an approximately rectangular cross-section of the filled big bag. It is preferred to reweigh the filled big bag after completion of the filling process for example on a weighing table. The big bag is as a rule weighed for example on a previously weighed pallet so that the precise filled weight may be concluded from the known weight of the bag material and the pallet. The result of such a weighing operation may be taken into account in the subseguent filling process to still further enhance the preci- sion. The apparatus 1] serves in particular to bag lightweight and ultralight materials such as silicates or carbon black or other lightweight materials showing a bulk material compactness of less than 0.25 kg per liter of volume.
These lightweight mate- rials tend to be difficult to bag due to their high air content.
If these lightweight bulk materials escape, a floating cloud builds in the surrounding space which settles not at all or else extremely slowly.
The apparatus 1 is in particular employed for filling big bags consisting of a coated material showing low deaeration ca- pacity.
10 A filling process may always be concluded by lowering the head plate device to equalize a debris cone of the fine or superfine filled particles.
The supporting device 40 may be lifted for removal to unweight the holding loops 11 so that the holding loops 11 can be manu- ally removed from the holding hooks 8.
List of reference numerals:
1 apparatus 2 bulk material
3 frame structure 4 filling spout 5 weighing unit 6 compacting device 7 holding device
8 holding hook 9 diaphragm pump, conveyor element 10 big bag 10a standing surface 10b filling valve
11 holding loop 12 bottom end, bag bottom 13 filling mouth 14 aeration valve 15 weighing cell 16 head plate device 17 pressure sensor 18 pressing force sensor 19 support frame 20 deaeration device 21 bleed line 22 compensator 25 stop valve 26 stop valve 27 sampler 28 product feed line 28a stationary part 28b weighed part 29 compensator 30 compensating device 31 active unit 31a active surface 33 rest position 34 acting position 35 lifting drive 36 double-walled section 37 inner wall 38 wire mesh 39 product feed supporting device 41 supporting surface 42 roller 42a drive
43 home position 44 support position 45 displacement frame 47 cylinder
48 displacement flap 50 weighing table 51 weighing cell 52 roller 52a drive pallet