The invention relates to a method for operating a tubular bag machine for the continuous production of tubular bags, which are filled with a mixture of liquid and solid filling components, according to the preamble of both independent main claims.
From the state of the art, tubular bag machines for producing tubular bags are known for packing mixtures of liquid and solid filling components. These tubular bag machines comprise a biaxially driven transverse sealing device comprising two sealing jaws. These sealing jaws are displaced along a predetermined trajectory and can produce bottom transverse seams and top transverse seams on the previously formed film tube to seal the tubular bag from the top and the bottom.
In these machines, a compressing device, which comprises two compressing elements, is attached above the transverse sealing device. These compressing elements can be contacted on the outer side of the film tube. In addition, the two compressing elements can be displaced horizontally between a closed position and an open position. In the closed position, the two compressing elements compress the film tube so tightly that the film tube is compressed so as to be liquid-proof. As a result, it becomes possible to fill the film tube with the mixture of liquid and solid filling components before being transversely sealed, since the compressing elements prevent the filling material from flowing downward. Once the top seam of the preceding tubular bag has been applied below the compressing device and the bottom seam of the following tubular bug has been produced, the compressing device is moved to the open position and gravity causes the filling material to fall into the still open tubular bag.
Below the transverse sealing device of the generic tubular bag machine, a wiper device (stripper) is provided. This wiper device comprises two wiper elements, which are contacted on the outer side of the film tube and can be displaced horizontally between a wiper position and an open position. In the wiper position, the wiper elements abut against the outer side of the film tube and compress the two inner surfaces of the film tube against each other. If the wiper device is moved downward at a faster speed than the film tube, the solid filling components are wiped downward on the inner side of the film tube by the wiper elements. In this manner, the wiper device can remove solid filling components from the sealing area of the tubular bag on the inner side of the film web in order to enable sealing the film tube using the transverse sealing device without difficulty. When producing the tubular bags to be filled with a mixture of liquid and solid filling components, the problem in known machines consists in the still open tubular bags becoming strongly bulged in the area of the bottom seam after being filled with the filling components. If this bulged tubular bag is closed by applying a top seam using the transverse sealing device, a large amount of air is closed in in the area below the top seam. This air in the tubular bag has a negative effect on the storing properties of the tubular bag, since in particular oxidation processes of the filling material within the tubular bag are accelerated within the tubular bag due to the oxygen contained in the air. Moreover, the strong bulging of the tubular bag causes an inadvertent lengthening of the individual tubular bags between the bottom seam and the top seam, which leads to more film web having to be used and lower length of cycles when producing the tubular bags.
Starting from this state of the art, it is thus the object of the invention at hand to propose a new method for operating a tubular bag machine for the continuous production of tubular bags, which can be filled with a mixture of liquid and solid filling components, the air contained in the tubular bag being reduced, the required use of film web being reduced, and the maximum number of cycles for the production of tubular bags being increased. Furthermore, it is the object of the invention at hand to propose a tubular bag machine for executing the method according to the invention.
These objects are attained by a method and a tubular bag machine according to the teachings of both independent main claims.
Advantageous embodiments of the invention are the subject matter of the dependent claims.
The method according to the invention is based on the connection of a formatting device disposed below the wiper device. This formatting device is tasked with formatting the bag shape of the still open tubular bag, i.e., before the top seam has been applied. For this purpose, the formatting device comprises at least two formatting elements which are contacted on the outer side of the film tube. For this purpose, the formatting elements can be displaced between an open position and a formatting position. The horizontal distance between the formatting elements is larger in the open position than in the formatting position. When executing the method according to the invention, the formatting elements of the formatting device are in the open position before and/or while filling the tubular bag, i.e., when the tubular bag is still open but after the bottom seam has been applied. In this open position, the open tubular bag can become bulged to the side without difficulty as known, meaning the filling material can be added to the open tubular bag without difficulty. During and/or after filling the tubular bag with filling material and before producing the top seam, the formatting elements of the formatting device are moved to their formatting positions, i.e., being moved together horizontally. By moving the formatting elements together horizontally, the still open tubular bag is formatted in its form, i.e., its breadth is compressed. By compressing the still open tubular bag, the liquid column of the filling material rises in the tubular bag and pushes out air from the top area of the tubular bag. Once the formatting elements have reached their formatting position and consequently a specific amount of air has been pushed out of the tubular bag, the top seam can be applied to the tubular bag directly thereafter or after carrying out further method steps in order to close the bag in this manner. As a result, a significantly smaller portion of air or even no air is in the top area of the tubular bag owing to the formatting of the tubular bag using the formatting elements, meaning in particular the storage properties of the tubular bag packaging is significantly improved. Moreover, the length of the tubular bag, which is required for receiving the filling material volume, can be reduced and thus the number of cycles of the tubular bag machine can be increased for the production of the tubular bags.
In the continuously working tubular bag machine, the film tube is continuously pulled downward in the tubular bag machine. In order to be able to ideally carry out the formatting of the still open tubular bag despite the continuous downward pull of the film tube, it is particularly advantageous if the formatting elements of the formatting device contacted on the outer side of the tubular bag in the formatting position are moved vertically downward at the same vertical speed as the transverse sealing device just as the film tube is moved at the same speed. In this manner, an undesired relative movement between the formatting elements on the one hand and the film tube on the other hand is prevented.
To not impede the air from escaping the head area of the still open tubular bag, it is advantageous if the wiper device remains in the open position until the formatting device is moved entirely into the formatting position. Not until after the formatting position has been reached does the liquid level reach its highest level in the still open bag, meaning that no additional air can be pushed out of the open tubular bag via the formatting device. From this moment on, the wiper device is then closed and the process of wiping the solid filling components contacted on the inner side of the film material is commenced.
In order to be able to wipe the solid filling components contacted on the inner side of the film tube downward without difficulty, it is particularly advantageous if the wiper elements of the wiper device contacted on the outer side of the tubular bag in the wiper position are vertically displaced at a higher vertical speed than the tubular bag. The difference in speed brings about a relative movement between the wiper element and the film tube, through which the solid filling components clinging to the inner side of the film tube are wiped downward.
As soon as the formatting elements of the formatting device have been moved to the formatting position and have thus formatted the still open tubular bag in shape, a certain amount of residual air commonly remains above the filling material, as otherwise there would be a chance of solid or liquid filling components being caught in the sealing area between the inner sides of the filling tube. In order to press out as much residual air remaining in the open tubular bag as possible, it is advantageous if at least one air-permeable venting channel is formed between the inner surfaces of the tubular bag in the wiper position of the wiper device, air being able to escape the top area of the tubular bag via the venting channel. If the wiper elements of the wiper device in the wiping position are moved downward relative to the film tube with the corresponding relative movement, the solid filling components are wiped downward because of this on the one hand and at the same time the air closed in in the top area of the tubular bag is pressed outward. The air which has been pressed outward is guided outward between the inner surfaces of the tubular bag via the venting channel so that as a result, only very little or no residual air remains in the tubular bag.
Once the top area of the tubular bag has been mostly freed of air and, if applicable, only a minute residual air portion remains in the tubular bag, the top seam of the tubular bag is applied using the transverse sealing device, thus closing the tubular bag. With regard to the processing and packaging of filling material, which consists of a mixture of solid and liquid filling components, it is particularly advantageous if the compressing device forms two retaining zones in the closed position. In the lower retaining zone, the film tube is compressed as usual so as to be liquid-tight to prevent the liquid filling components from leaking past the compressing device positioned in the closed position. At the same time, a second, upper retaining zone is formed above the lower retaining zone, the film tube being compressed so tightly in the upper retaining zone while maintaining a liquid-permeable residual gap that solid filling components cannot pass the residual gap. The result of the two superjacent retaining zones of the compressing device therefore is that first, the solid filling components are retained in the upper retaining zone, while the upper retaining zone allows the liquid filling components to pass through the residual gap. These liquid filling components are then retained in the lower retaining zone. By opening the compressing device, both retaining zones are opened and gravity allows the liquid and solid filling component to slide downward into the open tubular bag.
The tubular bag machine according to the invention is characterized in that the formatting device, by means of which the still open tubular bag can be formatted in shape, is provided below the transverse sealing device.
In order to be able to variably adjust the tubular bag machine to the dimensions of the bulge when packaging different filling materials, it is advantageous if the horizontal distance between the formatting elements in the open position and/or the horizontal distance between the formatting elements in the formatting position is adjustable. By adjusting the respective distances, a reaction to the bulging of the open tubular bag after having been filled with filling material and to the respectively required kinematics for pressing out air from the top area of the tubular bag can be varied. It is generally arbitrary in which constructive design the formatting elements of the formatting device are realized. According to a preferred design, it is intended for the formatting elements to each comprise several rotatably mounted rolls, which are disposed parallel and subjacent to one another. Hence, the rotatable subjacent rolls form a wall, off of which the outer side of the tubular bag can roll. Both walls formed by the rolls of the two formatting elements can then be moved toward or away from each other. In this manner, the rolls of the two formatting elements together form a formatting chute which is adjustable in breadth and in which the open tubular bags can be compressed to be formatted in form. After the transverse sealing and severing of the tubular bags, they can slide downward out of the formatting chute essentially without resistance owing to the rotatable rolls. In order to be able to easily enable synchronicity between the formatting device and the transverse sealing device in vertical operation, it is advantageous if the formatting device and the transverse sealing device are vertically driven using a shared drive device.
In order to easily form a venting channel between the wiper elements of the wiper device when in the wiping position, it is advantageous if the wiper elements of the wiper device are resiliently mounted on the transverse sealing jaws. If the wiper elements are in their wiping position and compress the inner sides of the film web against each other and if the wiper device acts downward relative to the film tube, the filling volume enclosed in the tubular bag is simultaneously reduced so that the pressure of the residual air in the top area of the tubular bag rises accordingly. If this pressure of the residual air in the top area of the tubular bag exceeds a specific degree, the resiliently mounted wiper elements are slightly pressed away from each other, thus forming an air-permeable venting channel between the inner surfaces of the tubular bag. Owing to this venting channel, the air from the top area of the tubular can escape outward.
In order to easily form two superjacent compressing zones in the compressing device, it is advantageous if the compressing device comprises two pairs of superjacent compressing elements, for example compressing rolls. The distance of the two lower compressing elements is smaller in this instance, so that the two lower superjacent compressing elements, which are disposed as a pair, compress the film tube so as to be liquid-tight in the closed position of the compressing device. The two upper compressing elements, which are disposed as a pair, have a larger distance so that a liquid-permeable residual gap remains in the upper pressure zone in the closed position of the compressing device. The breadth of the gap in the upper pressure zone is chosen such that the solid filling components cannot pass the upper pressure zone.
Which design of compressing elements is used for forming the compressing device is generally arbitrary. It is particularly advantageous if the compressing elements are realized in the manner of compressing rolls, since the compressing rolls can roll off of the film tube and enable the relative movement between the compressing element and the film tube without difficulty in this manner.
With regard to a conveying resistance of the film tube, which is as small as possible, via the compressing device, it is advantageous if the compressing rolls can be driven by motor.
An embodiment of the invention is schematically illustrated in the drawings and is described in the following by means of an example.
Below wiper device 16, a formatting device 18 having two formatting elements 19 is located, tubular bags 20 still open at the top seam being able to be formatted in shape by means of formatting elements 19 after it having been filled with filling material.
In
In order to not seal in the air from air bubble 32 in tubular bag 20, formatting device 18 is subsequently moved into its formatting position, which is shown in
Once the air is essentially entirely pressed out of air bubble 32, as illustrated in
Number | Date | Country | Kind |
---|---|---|---|
10 2019 109 484.4 | Apr 2019 | DE | national |
10 2019 111 754.2 | May 2019 | DE | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2020/057280 | 3/17/2020 | WO |