DE3640520A1 - Process for the metering and packaging of pourable materials and packaging machine for carrying out the process - Google Patents

Abstract

Process for the metering and packaging of pourable materials and packaging machine for carrying out the process. In the packaging of bulk material in relatively large packaging portions, volumetric metering is generally used. The desired accuracy consequently cannot be achieved, particularly where larger portions are concerned. To solve this problem, according to the invention the filling-material quantity is weighed, specifically by means of a weighing device (W) which is placed onto a normal tubular-bag machine (S). The feed device for the filling material is for a large part supported on weighing cells (30, 32). The packaging machine is suitable for the metering and packaging of all bulk materials conveyable by means of a worm and can therefore be used in a versatile way in the packaging industry. <IMAGE>

Description

The invention relates to a method for dosing and packaging of bulk goods, in which the ver gripping good of a tubular bag machine, with at least a longitudinal sealing jaw, cross sealing jaws and a trigger device for peeling a packaging film from the the packaging bags are formed, fed and pre sealing with one on the tubular bag machine existing weighing device weighed and because of this Weighing the good portion to be packed poured exactly becomes. The invention also relates to a device device for performing the method according to the invention.

Powdery bulk goods are usually metered volumetrically with the help of screw feeders. With a volumetric Dosage cannot be abzupac in all cases portion of bulk goods with the required accuracy dose. This is due to the fact that the Density of batches to be packed is different, so that with higher specific density, higher weights be sufficient than with a low specific density. To the others can also use different ver Seals of the bulk material can be reached, so that at  high compression too heavy packs and at low Compression too light packs arise.

In order to avoid this disadvantage, this has already been done The above-mentioned method is used and a ge suitable packaging machine proposed (DE-OS 28 20 562). In the well-known packaging machine, the form school ter and the filling tube with the shaped bag over a Hanging device supported on load cells and used The total mass of the listed modules is known and can be a kind of zero mark for the filling quantity represent. Now fill in as much bulk material until the weighing device displays the desired filling quantity. On Instead of a volumetric measurement, a gravi metric measurement performed. Requirement for this The type of weighing is that all components before each weighing le, exert the forces on the whole to be weighed, so moved must be so that they can no longer exercise powers. For this purpose, the longitudinal sealing jaw, the clamping jaws for the production of the bag cross seams and a force reaction unit can be lifted off the film. Further the film must be set up by a dedicated facility tion are held in such a way that they are tension-free hold is.

Due to the many processes, the well-known packaging machine only work with a low number of cycles, i.e. their performance is poor. Another disadvantage is that the periodic relief of the film the smooth running the film over the form shoulder and the format tube disturbed becomes what is synonymous with malfunctions.

The invention has for its object a method and a device suitable for its implementation to create, which enables a high packaging performance Lichen, with high accuracy in the determination a portion of packaging should be guaranteed. The Packaging machine according to the invention is intended to be only ge wrestle require construction effort.

The procedure created to solve this task type is characterized in that the weighing before filling the goods on a cradle container is done, either by entering the contents portion in the weighing container or by means of the how Device-controlled draining of the filling portion from the weighing container of a good quantity that is larger than the portion of filling. With this procedure the Avoided difficulties arising from the weighing of the filled bag. The tubular bag machine is built normally, i.e. they are not lifting mechanisms required to the longitudinal sealing jaw, the cross seal bake and other parts to lift off. The tension of the film does not have to be changed. Through these simplifications can be a short cycle time of the packaging machine and achieve high performance.

The method according to the invention comprises both machines, where the filling portion when entering the Beu tel is weighed as well as packaging machines at de the weighing only when the goods are removed from the how container done. The first version has the advantage that weighing at the same time as closing a ge  filled bag can be done. The second version has that Advantage that long falls are avoided, which in particular is particularly advantageous where there is heavily dusting bulk goods are to be filled.

With a control of the speed of the dosing screw Claim 2 achieves a short filling time, because the contents portion is initially accumulated quickly and only in the critical final phase, which requires precise weighing filling speed prevails. The continuous ver run the change of the dosing screw speed according to claim 3 has the advantage that a jerk is avoided, the one Could trigger an incorrect measurement.

The nature of Verpac specified in claim 4 kungsmaschine refers to the generic term of the An Proverbs 4 also on DE-OS 28 20 562, so on egg ne packaging machine to carry out the process Claim 1, with a tubular bag machine on which a falling, preferably vertical filling tube, a shaped shoulder arranged at the top of the filling pipe, one across Longitudinal sealing jaw movable to the tube for the formation of the Longitudinal bag seam, be against each other transversely to the withdrawal direction movable cross sealing jaws for the production of head seams and bottom seam of the bag, a device for pulling off the the packaging film forming the bag and a drive device for coordinated drive of the aforementioned Ele elements and a weighing device for weighing Verpac servings.

According to the invention, such a machine is characterized records that the elements of the form, fill and seal machine are fixed, i.e. only those for making egg of the packaging bag can make the necessary movements NEN and that the weighing device on the tubular bag machine is set up and the entirety of one Weighing container, a dosing screw for dosing or discharging bulk goods from the weighing container, one  electric drive device for the elements mentioned te of the weighing device on a support frame for the ge named elements of the weighing device via weighing cells is supported, with the total mass to be weighed exercise-free compared to the filling pipe and to a zu Guide line are movable in the weighing container.

With a machine designed in this way, both variants can be used be carried out according to claim 1. However, at the first process variant are accepted that the dosing screw into the weighing container from above protrudes. In the second process variant, in the the dosing screw below the weighing container is arranged, the entire device can be very deep be classified as the dosing screw into the filling tube can grab.

The entire weighing device is preferably on Schwin supported dampers. This avoids transmission of inertia forces on the tubular bag machine Weighing device that lead to wrong results could. It is also advantageous for an exact Weighing that the drive device for the drive the dosing screw via vibration damper on the support frame of the weighing device is supported (claim 7).

In a preferred type of packaging machine (An Proverb 8) is the weighing device on the top of the Ge supported the tubular bag machine. Avoid det detects a special frame that the cradle independent of the tubular bag machine on the bo that supports. Such racks are still common. Due to the damping according to claim 6, such is order of the weighing device possible without the Ge accuracy of weighing is impaired.

Advantageously, all load cells are common to one arranged seed horizontal plane (claim 9). If  the center of gravity of the total weight also the measurement results are particularly accurate and also easily reproducible.

A locking slide, which is between one Storage container and the weighing container is arranged. Man can surely flood the weighbridge reach halters (claim 10). The Ver is also advantageous application of a horizontal screw conveyor according to claim 11. The screw conveyor has no weighing function and enables it also processes cohesive bulk goods and the whole low machine.

A compressible cuff (claim 12) is absolute tight and allows even with bulk of very small par Particle size does not mean that it gets outside. A fall tenbalgen practically forms no resistance against together push or pull apart, causing the cradle device completely shielded from the upper feed device is. The height adjustment of the dosing screw and its Drive device (claim 13) allows the use various format tubes with shoulder attached to them and thus a large area of application for the use of Packaging machine.

The use of a stirrer and a scraper fers according to claim 12, facilitates the dosing process can initially be carried out as volume metering, since the Volume dosing becomes more precise the better guaranteed is that the space between adjacent worm gears without Cavities are completely filled. This also contributes a reduction in the dosing time and thus to a highest possible number of cycles.

For the dosing of cohesive bulk goods, it is advantageous at the lower end of the screw tube, a sieve or a grid  to arrange (claim 15). Such goods are running not after when the screw rotation is finished. However, when processing easily flowing bulk goods a tight seal is provided (claim 16), the preferably in several open positions with different which opening widths can be brought. Towards the end of the Abga be, i.e. shortly before the target weight is reached the opening width is reduced. This works particularly well realize with a shell closure according to claim 13.

The packaging machine according to the invention allows Installation of a vibrator below the bag-Ab fork place (claim 18). This is without disadvantage for that Weighing accuracy possible if vibration damper in accordance with Claim 6 can be provided.

Exemplary embodiments of the invention are shown in the drawing shown. Show it:

Fig. 1 shows a schematic representation of a side view of a packaging machine according to the invention,

Fig. 2 shows a horizontal section along line II-II in Fig. 1,

Fig. 3 partly in view, partly in section, a schematic representation of a part of the packaging machine Ver forming weighing device,

Fig. 4 shows a closure device for the metering screw, as is used especially for easy-flowing bulk goods and

Fig. 5 shows a variant of the actuating device for the closure according to Fig. 4.

The generally designated V packaging machine be available from a bagging machine S of traditional design, a weighing device W, the bag machine to the hose S is placed and a Speisungsvor direction Sp for the storage and supply of to be packaged bulk material weighing device W.

The tubular bag machine S has a frame 1 of the housing 1 , which is supported with feet 2 on the floor 3 . On the tubular bag machine is a for mat tube 4 on which a shaped shoulder 5 is arranged. Inside the format tube 5 there is a tube 6 , which is normally referred to as a filling tube, but does not come into direct contact with the filling material in the present case. Below the form shoulder 5 are arranged diametrically opposite one another, endless pulling tapes 7 , which press the packaging film 8 , from which the packaging bags are to be formed, against the format tube 4 .

The tubular bag machine S also has a longitudinal seal jaw 9 , which can be moved back and forth in accordance with the double arrow 10 , that is to say can optionally be pressed onto or lifted off from the film. An essential further component are transverse sealing jaws 11 and 12 , both of which can be moved in accordance with the double arrow 10 , the movements being coordinated in such a way that both jaws simultaneously migrate inwards and outwards at the same time.

Below the transverse sealing jaws 11 , 12 there is a compression device, designated overall by 13. This se has a support 14 for bags 15 , the content of which is to be compressed. The bags are supported by springs 16 , 17 on egg ner fixed support. Between the pad 14 and the pad 18 vibrators 19 , 20 are easily seen, with which the pad 14 can be set in vibration, thereby creating a compression effect of the bulk material in the bag 15 .

Within the housing 1, a supply roll 21 is mounted for packaging foil Ver. The packaging film 8 is guided over several deflecting rollers 22 to the form shoulder 5 and formed on the form shoulder into a tube, the edges of the film 8 overlapping, so that a longitudinal seam can be formed with the aid of the longitudinal sealing jaw 9 . The film is drawn off by means of the pull belts 7 in the work cycle of the machine. When the film is moved, both the transverse sealing jaws 11 , 12 and the longitudinal sealing jaw 9 are lifted off the film. The movements to be carried out by the described elements are generated by means of a drive which is arranged within the housing 1 . This drive is not shown in the drawing. Any known drive can be used.

The weighing device W is placed directly on the tubular bag machine S , namely on a support plate 23 which is located at the upper end of the tubular bag machine. A special framework for carrying the weighing device is therefore not provided.

The weighing device W has a support frame 24 which is supported on the support plate 23 via vibration dampers 25 , 26 . As the plan view of FIG. 2 shows, the support frame 24 is a beam structure consisting of a composite beam from the lower frame 27, extending from the corners of this frame posts 28 and a composite beam also from the upper frame 29. The bars are preferably hollow profiles of square cross-section. Three load cells 30 , 31 , 32 are arranged on the upper frame 29 . Here are on a crossbar of the upper frame 29 two weighing cells 30 , 31 and on the opposite crossbar only a single weighing cell 32 , which is seen in a projection perpendicular to the crossbar, in the middle between the two cells 30 , 31 . On the other hand, the weighing cells 30 , 31 are arranged symmetrically to the longitudinal axis 33 of the support frame 24 . All Wiegezel len 30 , 31 and 32 lie in a horizontal plane. The center of mass M should lie in the plane of the weighing cells 30 , 31 , 32 and if possible also so that all three weighing cells are loaded equally. This is at least approximately achieved when the center of gravity is at the point shown in FIG. 3. While in Figs. 1 and 2 load cells are shown, the horizontal forces can not record, Fig. 3 shows an alternative with a weighing cell 89 (Wiegebalken- weighing cell) through which the suspension frame 34 can be fixed.

A hanging frame 34 is supported on the support frame 24 . The hanging frame has a lower horizontal frame 35 and an upper horizontal frame 36 . These frames are supported against one another by posts 37 arranged on the frame corners. Posts 38 , 39 , 40 projecting upward above the upper frame 36 are provided to support the hanging frame 34 on the weighing cells 30 , 31 , 32 , the posts 38 , 39 (see FIG. 2) being extensions of the frame posts 37 , while the post 40 is fastened in the middle of the upper crossbar and can also pass through to the lower crossbar. The posts 38 , 39 , 40 are bent at right angles, whereby horizontal components 38 a , 39 a , 40 a are formed which rest on the load cells 30 , 31 , 32 .

On the lower frame 35 of the hanging frame 34 , a telescopic column 41 is supported, namely via a vibration damper 42nd The telescopic column 41 carries a housing 43 which is also designed as a horizontal arm (see also FIG. 3). In the housing the Antriebseinrich lines for a dosing screw 44 are housed. The dosing screw opens with its upper end in a how container 45 , which is designed as a downwardly converging funnel ter. In the weighing container opens a tube 46 , entered into the container 45 through the bulk material who can.

The mass supported on the load cells 30 , 31 , 32 is also supported on the support frame 24 with links designed as rod springs on the support frame. Two handlebars are visible in Fig. 2. These are the two relatively thin bars that run parallel to the long sides of the upper frame 29 . In Fig. 1, the three attachment points of the viewable handlebar there are shown.

The dosing screw 44 has a worm tube 47 and a worm shaft 48 , which serves as a carrier for band-shaped screw turns 49 . The screw tube 47 is closed at the bottom by a sieve 50 .

A drive motor 51 , to which a unit 52 with clutch and brake is flanged, and an angular gear 53 serve to drive the metering screw. The worm shaft 48 is coupled via an intermediate shaft 54 via a hitch 55 with the actual worm shaft 48 . A scraper 56 and a stirrer 57 are arranged in the area of the weighing container 45 . These elements are connected to a hollow shaft 58 which is penetrated by the intermediate shaft 54 already mentioned. The hollow shaft 58 is driven by a gear motor 59 to which an angular gear 60 is flanged. The output shaft of the angular gear is designed as a toothed pulley 61 which is in engagement with a toothed belt 62 which in turn is in engagement with a toothed pulley 63 . The scraper 56 runs close to the conical wall of the weighing container 45 , while the stirrer 57 is curved so that it also reaches filling areas that are at a distance from the funnel wall.

The supply device Sp has a storage silo 64 which (only symbolically indicated at 65 ) is supported on the housing 1 or on parts firmly connected to it. The storage silo can hold a large amount of bulk goods.

The silo has a lower outlet 66 which opens into a horizontally arranged conveyor 67 . Vorzugswei se, the conveyor device 67 is a screw conveyor, which is driven by an electric motor 68 , namely via reduction gear 69th The conveyor device 67 is abge based on the machine part symbolically shown at 70 . The conveyor has an outlet nozzle 71 to which a slide 67 is flanged. The slide 67 can be brought by means of a drive motor 73 from an opening position into a closed position. A round bellows 74 is flanged to the slide 67 , which in turn is flanged to the already mentioned tube 46 , which opens into the weighing container 45 .

Fig. 4 shows a variant for the outlet from the weighing container 45th The closure 75 has two half-shells 76 and 77 which can be actuated at will. Both half-shells 76 , 77 can be pivoted about an axis 78 and can be brought into different opening positions with opening angles α (wide openings) and opening angles β (small openings). The various opening positions are automatically created, for which purpose an actuating device acts on each half-shell. The two actuating devices are of the same design, which is why only the actuating device for the half-shell 76 will be described below.

The actuator has an actuator rod 79 which is hinged at its lower end with a joint 80 on the half-shell. The upper end of the rod 79 engages a joint 81 of a crank disk 82 . The crank disc 82 is located on a shaft 83 which is rotatable in a bearing block 84 .

The half-shell 76 can be rotated step by step by means of a pneumatic cylinder 85 or alternatively by means of an electrically driven stepping gear 86 . Thus, the two opening positions described are adjustable and also a closed position in which the opening angle is zero, so to speak.

Another alternative is shown in FIG. 5. Referring to FIG. 5, a pneumatic cylinder for adjusting the half-shell closure used 87 which is secured at its upper end somehow of the mass to be weighed and engages at its lower end a rod 88, the egg nen to the or the other of the two half-shells leads. A pneumatic cylinder 87 is assigned to each half-shell.

The weighing device works as follows. Before weighing is carried out, the weighing container 45 is filled, the general aim being to maintain a more or less complete filling. After weighing has ended, a new weighing process can be initiated. The mass is determined using the Wiegezel len 30 , 31 , 32nd First, the dosing screw is operated at a relatively high speed (e.g. 450 rpm) until the largest part (e.g. 90%) of a good portion (e.g. 20 kg) is dispensed by the dosing screw . For fine dosing, the speed of the screw conveyor is reduced (e.g. to 60 rpm). When the target weight is reached, the dosing screw is suddenly stopped using the brake contained in the unit 52 . In order to reliably prevent a drop of bulk goods in the case of easily flowing bulk goods, a locking device, e.g. B. FIGS. 4 and 5 can be used.

The transition from the initial high speed to the lower end speed of the screw conveyor can be fluent be, with the time-mass curve steep in the lower area  and in the upper area with less incline, however on in any case with a positive slope. Through a such a continuous course of the speed change avoided a jolt that could generate a force component te who pretends that the target weight has reached or even is exceeded.

With this type of weighing there is a subtraction, so to speak executed, d. that is, supported by the whole on the scale mass (several hundred kilograms) becomes one Quantity removed that is equal to the setpoint of a package to be packed Serving corresponds.

When processing powdery, cohesive material, a sieve 50 is sufficient to ensure that a further dispensing of filling material is interrupted immediately when the rotation of the screw 48 , 49 is stopped. When processing easily flowing bulk material, however, a complete conclusion is required, for. B. with devices according to FIGS. 4 and 5.

After the bulk material has fallen into the bag 15 , who actuates the transverse sealing jaws 11 , 12 , the top seam of the filled bag and the bottom seam of the next bag being formed at the same time, and at the same time the filled bag is separated from the empty film tube. If necessary, the filled bag 15 is compressed on the compression device 13 .

The packaging machine shown in the drawing has the Advantage that the dispensing of the product at a very low lying place, so that the fall path for the filling well is exceptionally low. This is very special then an advantage when packing very dusty goods shall be.  

As already mentioned at the beginning, the invention also includes a packaging machine in which the metering cylinder is arranged above half of the weighing container 45 . In this case, the weighing container 45 is completely emptied after each filling and during weighing, with the help of the dosing screw, which then lies above the weighing container 45 , the exact amount (weight) of bulk material is given. In this case, the "subtraction method" is not used, but an addition method in which the mass of a portion of the packaging is added to the masses supported on the weighing cells.

The scraper 56 and the stirrer 57 also ensure that the bulk material falls safely into the screw 48 , 49 and that there are no cavities.

The telescopic support 41 has the advantage that the Antriebsein directions for the metering screw and thus the metering screw itself are adjustable in height, namely by lengthening or shortening the telescope. This allows the use of different format tubes 4 and thus a universal usability of the machine.

Claims (18)

1. A method for dosing and packaging of bulk goods, in which the goods to be packaged are supplied with a tube bag machine with at least one longitudinal sealing jaw, cross sealing jaws and a pull-off device for removing a packaging film from which the packaging bags are formed, and before closing with a Weighing device located on the tubular bag machine and due to this weighing the product portion to be packed is poured exactly, characterized in that the weighing takes place before filling the goods in a weighing container, either by entering the filling portion into the weighing container or by means of the Weighing device controlled draining of the filling portion from the weighing container from a quantity of material which is larger than the filling portion. 2. The method according to claim 1, characterized in that the speed of the dosing screw is controlled so that in the dosing screw with height The speed runs than in the final phase of metering. 3. The method according to claim 2, characterized in that the speed transition from the initial phase to the final phase con is temporary. 4. Packaging machine for carrying out the method according to claim 1, with a tubular bag machine, on which there is a falling, preferably vertically extending filling tube, a shaping shoulder arranged at the top of the filling tube, a longitudinal sealing jaw which can be moved transversely to the tube for forming the Beu tellängsnaht, transversely to the withdrawal direction against each other moveable che cross sealing jaws for the production of top seam and bottom seam of the bags, a device for removing the packaging film forming the bag and a drive device for coordinated drive of the elements mentioned and a weighing device for weighing packaging portions, characterized in that the elements ( 5 , 9 , 7 , 11 , 12 ) of the tubular bag machine ( S ) are arranged in a fixed position, ie only the movements necessary for the production of a packaging bag ( 15 ) can be carried out and that the weighing device ( W ) is placed on the tubular bag machine ( S ) and the whole from a cradle e container ( 45 ), a dosing screw ( 44 ) for dosed entry or from carrying bulk material from the weighing container ( 45 ), an electric drive device for the elements of the weighing device ( W ) on a support frame ( 24 ) for the said elements the weighing device ( W ) is supported via weighing cells ( 30 , 31 , 32 ), the entire masses to be weighed being able to be moved into the weighing container without friction with respect to the filling pipe ( 6 ) and with respect to a feed line ( 46 ). 5. Packaging machine according to claim 4, characterized in that the metering screw ( 44 ) protrudes into the filling tube ( 6 ) and is surrounded by a screw tube ( 47 ), the outer diameter of which is smaller than the inner diameter of the filling tube ( 6 ). 6. Packaging machine according to one of claims 4 and 5, characterized in that the entire weighing device ( W ) is supported on vibration dampers ( 25 , 26 ). 7. Packaging machine according to claim 6, characterized in that the drive device ( 51 , 52 , 53 ) for driving the metering screw ( 44 ) via vibration damper ( 42 ) on the support frame ( 24 ) of the weighing device ( W ) is supported. 8. Packaging machine according to one of claims 4 to 7, characterized in that the weighing device ( W ) on the top of the housing ( 1 ) of the tubular bag machine ( S ) is supported. 9. Packaging machine according to one of claims 4 to 7, characterized in that all weighing cells ( 30 , 31 , 32 ) lie in a common horizontal plane and the center of gravity ( M ) of the total mass supported on the weighing cells ( 30 , 31 , 32 ) is at least approximately in this plane, preferably three weighing cells being arranged in the plane mentioned. 10. Packaging machine according to one of claims 4 to 9, characterized in that a gate valve ( 67 ) is arranged in a feed line ( 71 , 46 ) leading from a bulk material storage container ( 64 ) to the container ( 45 ). 11. Packaging machine according to one of claims 4 to 10, characterized in that between the bulk material storage container ( 64 ) and the weighing container ( 45 ) a Förderschnec ke ( 67 ) is arranged, which preferably runs horizontally and preferably in front of the gate valve ( 67 ) according to claim 10. 12. Packaging machine according to one of claims 4 to 11, characterized in that in the feed pipe ( 71 , 46 ) to the weighing container ( 45 ) an axially compressible man cuff ( 74 ) is installed, preferably a round fold bellows from a bendable, preferably inextensible not elastic material. 13. Packaging machine according to claim 12, characterized in that the metering screw ( 44 ) together with its drive device is height adjustable. 14. Packaging machine according to one of claims 4 to 13, characterized in that in the funnel-shaped weighing container ( 45 ) a stirring device ( 57 ) and a scraper ( 56 ) running close to the container wall are arranged, the drive of which is preferably independent of the screw ( 51 , 52 , 53 ). 15. Packaging machine according to one of the preceding claims 4 to 14, characterized in that, vorzugswei se for the promotion of cohesive bulk goods, at the lower end of the screw tube ( 47 ) a sieve ( 50 ) or grid is arranged. 16. Packaging machine according to one of claims 4 to 13, characterized in that, preferably for the packaging of easily flowing bulk goods, a tight closure ( 75 ) is arranged at the lower end of the screw tube, which preferably in several opening positions with different opening widths ( β , α ) can be brought. 17. Packaging machine according to claim 16, characterized in that the closure of spherical shells ( 76 , 77 ) be, which are pivotable relative to each other, preferably by means of hinged rods ( 79 ; 78 ) which are arranged between the screw tube and filling tube and which lead to an electrical or pneumatic actuating device ( 86 ; 85 ). 18. Packaging machine according to one of claims 4 to 17, characterized in that below the delivery station for filled bags ( 15 ) a compression device ( 13 ), preferably a vibrating device, is arranged to compress the content of the bag.