Sterilizer for grain in bags - injects heavier than air gas before filling of bag container

The invention relates to a method for the sterile filling of liquid, powdered, granular or granular filling material in containers or containers. The method relates to a method for sterile filling of liquid, powdery, granular or granular filling material into containers or bags of sealable material. Bags made of sealable material, in which initially produced an open-topped container, then the contents introduced from above into the container, the air present in the container expelled and the container is completely closed.

For sterile and germ-free filling of flow or

pourable Good must be taken at the filling station that during the filling of the filling until the complete closure of the filled container, a vacuum or a sterile inert gas atmosphere is maintained. The insertion of the machine parts directly involved in the filling and closing of the container into a vacuum or protective gas chamber or autoclave is extremely costly and time consuming. The other possibility, the vacuum or the inert gas atmosphere to essentially limit the container interior, that is, expel the air before filling the filling material from the container interior, are mainly against sealing problems and difficulties in the maintenance of an economical machine cycle.

In particular, when Eirhihren the filler in the regularly open top container when removing the container to close the open top and when removing the filled or partially filled container can be a A atmosphere exchange, ie difficult to prevent the ingress of ambient air in the still open container.

This is where the invention intervenes. It is the object of reducing the time and cost of sterile filling any type of flowable or pourable Good in containers, in particular, the conditions are to be created that the container manufacturing and achieving a sterile atmosphere in the container largely at the same time with the filling can be done.

Based on a method of the type described above, the invention proposes to solve this problem that for expelling the air present in the container a sterile inert gas is injected with a greater specific gravity than air before introducing the contents from above into the container the injection quantity is at least so large that the portioned filling material and the protective gas completely fill the container before it is closed. Because of the higher specific gravity of the protective gas, this displaces the air in the container interior to the open top of the container, so that the container interior regardless of the use of a sealed chamber, for. As a vacuum chamber or autoclave, and is released without special sealing measures on the filling side of the harmful air atmosphere reliable. At the same time the conditions are created so that the container after filling, the inert gas atmosphere is largely expelled by the heavier contents from the container interior up, can be closed in the filling station without special machine cycle disturbing or delaying operations.

The process according to the invention proves to be particularly advantageous in the production and filling of bags made in a strand or hose of band-shaped film material. Here, the invention is provided in a further development that the band-shaped foil material is folded over a metering tube and a gassing tube such that the two longitudinal edges of the foil strip are superimposed that the resulting foil strand is then welded to the superimposed longitudinal edge portions and at least partially moved down into a filling zone in that a bottom weld is applied in or below the fill zone, that in the provided with the bottom weld seam foil the protective gas and then the contents are introduced into sufficient for bag filling amount and that finally the film strand with the filled strand section down from the filling zone and the bag forming portion is closed at the top. This method example has the particular advantage that the processes of introducing the sterile protective gas atmosphere into the bag interior, filling the flowable material and producing the bag welds can be summarized substantially spatially and temporally. This is done in a further development of the invention in that the film strand is lowered when removing the filled portion of the filling zone by about one bag length, that in each case the closure weld of the filled bag are made simultaneously with the bottom weld of the bag to be filled below and that the two adjacent welds be separated in the welding position transversely to the bag axis.

Since the filling inevitably portioned and thus takes place at intervals, it is expedient for economic reasons that the inert gas injection intermittently takes place in such a way that it starts before the introduction of the filling material and is continued periodically over a portion of Füllgutzufuhr. In an alternative procedure, the inert gas injection into the interior of the film strand can be continued continuously during the step-by-step production and filling processes of the bag chain. The increased shielding gas requirement in the continuous supply of protective gas is economically justifiable that the Füllgutaufgabe is interrupted in the production and filling of the bag chain or the bag string only during the short welding interval in the production of the bottom weld.

The filling machine suitable in particular for carrying out the above-mentioned method for filling bags made from a film strand has a film folding device, a welding device arranged in the direction of movement of the film behind the folding device parallel to the longitudinal edges of the film for producing the longitudinal weld seams, furthermore a film transport device which follows the film strand after the film Production of longitudinal welds pushes into the filling zone, an approximately coaxially from above into the interior of the film strand engaging metering tube, at the free end in the region of the filling zone an externally controlled metering valve is arranged, and a transverse welding device for producing the transverse bag welds on. This filling machine according to the invention is characterized in that a gassing tube with an opening nozzle next to the dosing in the approximately vertically extending film strand from above engages so far that it opens at the level of longitudinal welding or deeper into the film strand. Since the sterile shielding gas injected into the bag inside the bag has a higher specific gravity than air, the arrangement of the mouth of the gassing tube is only bound to the condition that the supplied protective gas reaches the interior of the bag. The replacement of the previously located in the bag interior air through the inert gas then takes place automatically for physical reasons.

The film strand or the bag chain can therefore be continuously lowered while maintaining a sterile protective gas atmosphere in the bag interior even during the filling process up to the transverse welding jaws.

In a further development of the filling machine according to the invention, it is provided that the gassing tube and the metering tube in the longitudinally welded strand section are approximately vertical and parallel to the strand axis and that both tubes are bent over the jaws of the longitudinal welding device to the side and between the folded-up longitudinal edges of the web-shaped starting material. Preferably, a rod assembly is provided for the forced operation of the metering valve, which has at least one parallel to the metering and gassing tubes in the interior of the strand engaging straight rod which is mounted vertically movable and connected to an actuator of the metering valve.

In order to ensure a reliable transport and advance of the film strand or other container material to the filling zone and from the filling zone regardless of the quality and strength of the material is provided in Welterbildung the invention that above or approximately equal to the mouth of the gassing a forming the transport device Double roller take-off device is arranged, which engage with two pairs of rollers at two diametrically opposite longitudinal edges of the film strand and can be actuated at intervals for pushing the film strand into the filling zone. The two driven pairs of rollers ensure a smooth and wrinkle-free feeding of the bag during and after filling and are able to compensate for any differences in thickness on both sides of the bag. Preferably, it is provided for this purpose that a roller of each roller pair is mounted on an arm of a pivotable about an axis parallel to the roller axis lever, that the roller is pressed by the lever with adjustable spring force against the stationary mounted other roller and that a drive pinion for the pivotable roller is mounted on the pivot axis of the lever The drive pinion remains due to its arrangement on the pivot axis of the lever in constant positive engagement with the driven gear even if the gap between the two rollers of the roller pair is changed. About the lever, the pressing force of the rollers can be adjusted without difficulty.

However, the inventive method is not limited to the production of strand or tubular bags, but can be used in particular because of the extensive independence of the protective gas supply to the container interior with the advantages described above even when filling cartons, bags or largely rigid containers.

In the following the invention will be explained in more detail with reference to an embodiment shown in the drawing. 1 shows a schematic axial section through that part of the filling machine in which the bags are welded, filled and closed; FIG. 2 shows a sectional view in the direction of the arrows II - II of FIG. 1 of a roll withdrawal located above the filling zone; FIG. and FIG. 3 shows a partially sectioned side view in the direction of the arrow III in FIG. 2.

The processing station shown schematically in Fig. 1 is used to produce bags from a film web and for filling a flowable or pourable product in the bag and for closing the filled bag. The generally withdrawn from a roll of film web is first folded with a folding device, not shown in the drawing along the central axis and stacked with the two web halves. In this folded state, the film web 1 is fed to the processing station shown in FIG. The folded film is drawn from above over a dosing tube 3 and an existing parallel to this gassing 5 arrangement, the tube assembly engages from the side into the gap between the unwelded edges of the film web. Behind the entry point, the two tubes 3 and 5 in the coincident with the direction of movement of the longitudinal direction of the bag string or

Hose bent. Also substantially parallel to the metering tube 3, a linkage arrangement 7 is inserted between the folded-up sides of the film. The linkage arrangement 7 serves, as will be explained in more detail below, the actuation of a metering valve 9 arranged at the lower end of the metering tube.

The two the pipe and rod assemblies at the introduction site outside enclosing film edges are merged again below-the insertion point and welded together between the welding jaws 11 for producing the longitudinal weld.

To accelerate the curing of the weld, it is usually cooled immediately after welding. The tube-like film strand produced in this way is pushed into the filling zone 15 by means of a draw-off device 13 shown schematically in FIG. 1 by two rollers, in which the metering tube 3 ends with the metering valve 9. Below the filling zone 15, two transverse welding devices are arranged in the illustrated Ausführungsbespiel, one of which is used with a pair of jaws 16 for producing the bottom weld the bag and the other with a below the pair of jaws 16 arranged jaw pair 17 for producing the bag-closure weld. Between the two pairs of jaws 16 and 17 eim separator 19 is arranged, which separates the filled and sealed by means of the pair of jaws 17 bag 21 of the overlying film strand.

The metering valve 9 is formed in the illustrated embodiment as Dosierkegel that can be lifted by axial displacement of a rod assembly belonging to the bumper pair 7 down from its seat, wherein the filling material located in the tube 3 portioned flows into the filling zone 15.

The gassing pipe 5 discharges above the metering opening of the metering valve 9 approximately below the roller take-off 13 into the interior of the film strand 1.

As can be seen in the illustration according to FIG. 2, the linkage and pipe arrangements extending in the line interior are enclosed in the end region above the take-off device 13 by the flange part of a film spreader 25. The Folienbreithalber serves to spread the strand opening cross-section and for lateral guidance of the detected by the discharge device 13 Strangränder. Preferably, in addition to the illustrated spreader 25, a second spreader is disposed below the trigger device.

In Fig. 1 as a whole with 13 designated roll withdrawal device is shown in Fig. 2 in plan view. It has four pairs of cooperating rollers 26a, 26b and 27a, 27b, which engage on both sides of the longitudinally welded film strand in the region of the parallel longitudinal edges or the longitudinal weld seam. All roles are connected in the illustrated embodiment via a positive gear and a magnetic coupling and braking device with a drive motor.

The rollers 26a and 27a shown at the bottom in FIG. 2 are pivotable about an axis 29 parallel to the roller axis (FIG. 3) to change the associated roller gap. For this purpose, the rollers 26a and 27a are each mounted on a double lever 31, at the opposite lever arm an adjustable clamping device 33 engages. The drive of the pivotally mounted rollers 26a and 27a via a pinion 35 which is mounted on the pivot axis 29 of the lever 31. Due to this arrangement, the drive for the rollers 26a and 27a is independent of the pivotal position of these rollers.

The described double roller draw ensures an effective and bilaterally uniform transport of the film strand 1, regardless of the strength of the guided in the gap between the pairs of rolls material.

The method for producing the bags and for filling them with the contents introduced via the metering tube 3 can best be explained with reference to the representation according to FIG. 1. The centrally folded film web 1 is removed via the pipe and rod assembly 3, 5, 7 down. The spread over the introduction of the pipe assembly edges of the film 1 are merged below the Eirführungsstelle and welded between a pair of welding jaws 11. Preferably, the one-sided longitudinal weld in a subsequent welding step is so oversized that weldable material is urged in front of the end edges and completely closes the edges to the outside and covers. The produced longitudinal weld is cooled and the longitudinally welded, ie about tubular Kge foil strand down into the filling zone 15 advanced.

Then, the bottom weld for the next to be filled bag of the welding jaws 16 is produced. Even during the welding process, the interior rn,.

Aes nacn oten nin open rollstrantyw would be flushed through the mouth 23 of the gassing 5 exiting protective gas, which displaces the air from the interior upwards due to its higher specific weight compared to air specific gravity. This displacement of the air also takes place when the film strand 1 is moved in the feed direction. The filling of the filling takes place only after the beginning of the protective gas injection, so that the contents within the bag does not come into contact with germ-containing air.

Due to the heavier filling material, the protective gas is expelled upward from the bag interior; the inclusion of protective gas residues in the bag is - unlike air - unpopular.

After filling of the contents corresponding to a bag contents, the strand 1 is pushed down by about one bag length with the help of the roller removal device 13. The upper end of the bag is provided with the help of the welding jaws 17 with a closure weld, after which the filled bag 21 can be removed after separation above the sealing weld from the processing station.

To save time-consuming work cycles, the production of the bottom weld of a hose section to be filled between the welding jaws 16 and the production of the closure weld of the previously filled bag 21 between the welding jaws 17 is carried out substantially simultaneously, and the separation of the filled bag 21 takes place in the cooling phase of the two adjacent transverse welds.

The timing of the production of longitudinal welds, the intervalwise advancement of the film strand 1, the inert gas injection through the gassing tube 5, the opening and closing of the Dosierkegels 9 via the linkage assembly 7 and the production of the bottom and closure welds and the separation of the respective filled bag 21st are matched or synchronized, for example via a program roll.

The Vorrällting described for the production and filling of bags can be used without substantial change for the production and filling of two superimposed film webs tubular bags. For this purpose, a second longitudinal welding device is arranged on the welding jaws 11 diametrically opposite side of the tube assembly, which is operated simultaneously with the welding device shown in the embodiment.