GB2196313A

GB2196313A - Apparatus for filling and sealing open bags

Info

Publication number: GB2196313A
Application number: GB08723685A
Authority: GB
Inventors: Alois Combrink; Hans Muterthies
Original assignee: Haver and Boecker OHG
Current assignee: Haver and Boecker OHG
Priority date: 1986-10-14
Filing date: 1987-10-08
Publication date: 1988-04-27
Anticipated expiration: 2007-10-08
Also published as: FR2604971A1; ATA203687A; AT406252B; IT1213899B; DE3634890C2; FR2604971B1; GB2196313B; DE3634890A1; GB8723685D0; IT8712534A0

Abstract

In apparatus for filling and sealing double-seamed bottom bags having an internal coating there are in addition to impressing elements 10, 11 pivotable about horizontal axes (8, 9), pressing strips (16, 17) which move in a vertically downwards direction after closure of the impressing elements to press the bagwalls against the contents to express air from the bag. Instead of the pressing strips 16, 17, a suction nozzle 20 (Fig. 4) can be provided to extract the air, said nozzle being vertically displaced into the bag, passing between the impressing element 10, 11. So that the top edge of the bag is maintained at the same height, a bag conveyor 2 is vertically movable. By reason of the additional pressing strips 16, 17 or by reason of the suction nozzle, the air present inside the bag is extracted despite the stiffness of the bags. Since no air cushions are able to form, the strain on the interior sealing seam is relieved so that it can reliably be assumed that the bags are sealed in absolutely airtight fashion. <IMAGE>

Description

SPECIFICATION Apparatus for filling and sealing open bags The invention relates to apparatus for filling and sealing open bags.

The invention is particularly but not exclusively applicable to apparatus for filling multilayer double-seamed bottom bags with a filler nozzle to which the bag to be filled is applied and with a squeezing means for impressing the upper portion of the filled bag and comprising, pivotable about horizontal axes, two mutually parallel impressing elements.

In previously proposed apparatus for filling open bags, the impressing elements have been rod shaped. The rods which are moved towards one another after the bag has been filled on the one hand force out of the bag the air which is above the contents, while on the other hand, in order to close the bag, the bag walls are applied against each other above the contents filled thereinto. Previously proposed apparatus has been designed for bags which have a relatively inherent rigidity.

Such bags are, for example, flat or gusseted bags of synthetic plastics material or paper bags.

Apart from the already mentioned bags, multi-layer double-seamed bottom bags are also known which have lateral gussets. these are open bags. To manufacture the bags, a tube portion which serves as a blank is folded over at one end. The end edges of the layers which form a bag wall are offset in relation to one another, a feature referred to in the art as staggering. Such bags have substantially greater inherent stability than ordinary flat or gusseted bags of paper or synthetic plastics material.

Where double-seamed bottom bags are involved, moisture proof versions are known.

The inner layer of these bags has an aluminium coating on the side facing the interior of the bag. So that such bags can be sealed in an absolutely airtight manner, a further coating of synthetic plastics material is then applied to the aluminium coating. When the bottom of the bag is formed or when it is sealed, the layers of synthetic plastics material are welded to one another so that the need for an airtight construction is satisfied but only if it is ensured that after filling and sealing of the bags, no loadings are applied to the weld. To this end, it is necessary that no cushion of air forms in the sealed bag from the residual air which may be present therein.

Filling and sealing of open double-seamed bottom bags is not possible on previously proposed apparatus since there is always some, even if minimal, air remaining in the bag. Since relatively considerable excess material is needed for sealing a filled doubleseamed bottom bag, the edges of rod-shaped pressure-applying elements are not suitable for expressing the air, since they are applied immediately above the contents of the bag. This leads to a spreading-out of the wall parts located above the impressing elements. It should further be mentioned that in the case of the tube portions used for producing double-seamed bottom bags, the walls on one side are offset in relation to the other so that the adjacent walls can be connected to one another by a sealing seam.

According to one aspect of the invention there is provided apparatus for filling and sealing open bags by means of a filler nozzle to which the bag to be filled is applied, the apparatus comprising two mutually parallel impressing elements pivotable about horizontal axes, and squeezing means for impressing the upper portion of the filled bag and comprising downwardly movable pressing strips which are associated with the impressing elements, the pressing strips being offset in relation to the moved together impressing elements, once the impressing elements have been moved together being movable towards upper portions of the bag walls shaped by the impressing elements, and being lowerable to apply the bag walls against the filled contents, the bag, at least while the impressing elements are moving towards each other, being supported on a conveyor which is movable towards the impressing elements.

After the impressing elements have moved together, there remains above the filling content a cross-sectionally triangular space bounded by the bag walls. The bag walls are pressed by the lowerable pressing strips until they bear on the contents, causing the air to be forced out of the space. As this happens, the bag walls are slightly stretched. By reason of the conveyor carrying the bag, the equipment and components associated with the mouth of the bag need not apply any notable force to hold the bag. Since the conveyor is lifted during closure of the impressing elements, it is ensured that the upper edge of the bag is not pulled downwardly. The vertical position of the bag edge therefore always remains at the same level.

Expediently there is provided on either side of each impressing element one of the pressing strips, each pressing strip having its own drive. Thus, the pressing strips are capable of movement independently of one another. It is particularly suitable if each drive comprises a piston-cylinder unit. In addition to giving a high pressing force, it can always be ensured that also the bag walls are applied against the contents, even when the upper face bounding the contents extends obliquely. A structurally simple solution can be achieved if the drives for the pressing strips are disposed on the levers which carry the impressing elements.

According to another aspect of the invention there is provided apparatus for filling and sealing open bags by means of a filler nozzle to which the bag to be filled is applied, the apparatus comprising two mutually parallel im pressing elements pivotable about horizontal axes and squeezing means for impressing the upper portion of the filled bag and comprising at least one vertically movable suction nozzle which can be connected to a suction source and is associated with the impressing ele ments, the suction nozzle being introduceable, after the impressing elements have been moved, into a space within the bag above the filling contents and defined by the bag walls, to evacuate the space and apply the bag walls against the filled contents, at least during eva cuation of the space the bag having supported on a conveyor which is movable towards the suction nozzle.

The suction nozzle which can be introduced into the interior of the bag builds up a vacuum in the space above the contents so that the upper portions of the bag walls are applied against the contents in the same way as in a shrinking process. Also this solution guarantees that after the bag is sealed, no air cush ion can form inside it.

In such apparatus multi-layer paper bags which are normally provided with an inner coating or an inner layer consisting of metal and/or synthetic plastics material can, once they have been filled, be so shaped in the upper portion that no residual quantity of air remains in the filled bag which might produce a cushion of air after the sealing process.

Which of the indicated solutions is used depends essentially on the contents but also on the type of bag used. When a suction nozzle is used, either the impressing elements are moved together only sufficiently that the suction nozzle can be passed through or recesses may be provided in the impressing elements to form an insertion aperture.

The indicated solution is particularly advantageous in the case of open double-seamed bottom bags. Since the excess length of a filled bag is relatively considerable, it is expe dient for the impressing elements to be plateshaped since they can then be so designed in their height that at least a part of the excess length is covered, to prevent the walls open ing out. The length of the plate-like impressing elements is attuned to the greatest bag width.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 to 3 show a first embodiment of apparatus according to the invention in three different operative positions; and Figure 4 shows a further embodiment but only in one position of operation.

Referring to the drawings, in both of the embodiments a filled bag 1 is shown standing on a conveyor 2 which can be raised and lowered as indicated by double arrow A. The contents of the filled bag extend as far as the undulating line identified by the reference numeral 3. As Fig. 1 in particular shows, there is on the filled bag 1 a relatively considerable excess length which arises from the fact that the bags involved are double-seamed bottom bags. In the case of the examples of embodiment illustrated, the bag 1 has been carried away from a filling nozzle, not shown, by pairs of grippers 5 disposed on a carriage 4. Onwards transport to a sealing machine, not shown, is effected by a belt transmission 6 and by a plurality of pivotable conveyor rollers 7 disposed at the same height. The top edge of the bag extends as far as the top region of the belt transmission 6.As Fig. 1 furthermore shows, a space 1 a is located between the undulating line 3 and the as yet still closed pair of grippers 5. The apparatus illustrated furthermore comprise, pivotable about horizontal axes 8, 9, two pressure applying elements 10, 11 which, having regard to the stiffness of double-seamed bottom bags, are of plate-shaped construction and extend over the entire width of the bag. The impressing elements 10, 11 are mounted on angular levers 12, 13. Articulated on each angular lever 12, 13 is a piston-cylinder unit 14, 15 to cause pivoting about the horizontal axes 8, 9.

In the embodiment shown in Figs. 1 to 3, also two pressing strips 16, 17 are provided which extend over the total width of the bag, parallel and at a distance from each other and which are mounted on the piston rods of piston-cylinder units 18, 19. The piston-cylinder units 18, 19 are preferably so disposed that the pressing strips 16, 17 can move in a vertical direction. In contrast to the illustration in Figs. 1 to 3, however, an oblique position is also conceivable.

In the case of the embodiment shown in Fig. 4, instead of the pressing strips 16, 17, a slit-shaped suction nozzle 20 is provided which, in a manner not shown in detail, can move in a vertical direction as indicated by double arrow B. The suction nozzle 20 is connected by lines to a vacuum pump 21 and can be inserted into the cavity 1a. In Fig. 4, the suction nozzle 20 is shown in an intermediate position, to demonstrate that it can be inserted between the belt drive 6 and the conveyor rollers 7. For this purpose, at least one of the conveyor rollers 7 is removed. With regard to the illustrated in Fig. 4, the air already present in the space 1 a has been extracted via the suction nozzle 20. As the drawing shows, the space has shrunk so that the top walls of the bag lie closely against the contents.

It should also be mentioned that in the case of the embodiment of Fig. 4, either the plateshaped impressing elements 10, 11 are only moved together to an extent such that the slit-shaped suction nozzle 20 can be passed between them or they are pivotable into an intermediate position to allow such passage.

The filled bag removed from the filling noz zle is transported in the direction of arrow C to the conveyor 2 by the reciprocatingly moving carriage 4. The angular lever 13 which is in front in the direction of feed of the bag 1, and on which the conveyor rollers 7 and the plate-shaped impressing element 11 are disposed, isfor the purpose pivoted sufficiently high that the approaching movement of the bag is not restricted. As soon as the bag has been placed on the conveyor 2, the pistoncylinder units 14, 15 are so operated that the impressing elements 10, 11 achieve the extreme moved together position shown in Fig.

2. At the same time, also, the conveyor rollers 7 are pressed against the belt drive 6. As can be seen by comparing Figs. 1 and 2, the moving-together of the impressing elements 10, 11 substantially reduces the height of the space 1a. As indicated by Fig. 2, the pressing strips 16, 17 are sufficiently lowered that they bear on the obliquely extending bag walls. As shown in Fig. 3, they have reached a bottom position so that parts of the bag walls from the excess length are resting on the contents.

As comparison between Figs. 2 and 3 shows, the lowered pressing strips 16, 17, by reducing the volume of the space 1 a, have forced the air out of the interior of the bag. Carrying away the filled bags into the subsequently disposed sealing means is effected by the belt drive 6 which can be driven in cadence. The impressing elements 10, 11 constitute a guide for the upper compressed bag edge. Once the bag 1 has been removed from the area of the impressing elements, the apparatus is switched to bring in a new bag. Fig. 3 also shows that the carriage 4 with the pairs of grippers 5 for bringing in a new bag have been moved back into the starting position.

In the embodiment shown in Figs. 1 to 3, the pressing strips 16, 17 are disposed laterally alongside the moved-together plateshaped impressing elements 10, 11. For shaping of the top edge of the bag, it is necessary for the distance between the impressing elements 10, 11 and the pressing bars 16, 17 to be kept to the absolute minimum. As illustrated, the piston-cylinder units 18, 19 for moving the pressing strips 16, 17 are mounted on the levers 12, 13 which carry the impressing elements 10, 11, the levers 12, 13 being of angular construction. This construction affords the advantage that the movement of the impressing elements 10, 11 is not inhibited by the pressing strips 16, 17.

In the case of the embodiment shown in Fig. 4, the slit-shaped suction nozzle 20 is introduced into the bag after the plate-shaped impressing elements 10, 11 have been moved together. By a not shown system of controlling the vacuum, then, the air present inside the bag is extracted. Removal of the filled bag takes place in the manner already described, once the suction nozzle 20 has been moved into an extreme position situated above the belt drive 6.

In the examples illustrated, a lifting means 22 not shown in greater detail is associated with the conveyor 2. Thus, upon moving together of the impressing elements 10, 11, the conveyor 2 can be so lifted that the mouth edge of the bag remains at the same level.

Furthermore, the conveyor 2 accommodates the entire weight of the bag so that the equipment associated with the mouth of the bag need not absorb any notable forces and can therefore serve substantially to form and guide the top edge of the bag. The lifting arrangement is also effective when air is extracted from the bag 1 by the suction nozzle 20. The components needed for controlling and driving are not shown since they are part of one general state of the art.

Claims

1. Apparatus for filling and sealing open bags by means of a filler nozzle to which the bag to be filled is applied, the apparatus comprising two mutually parallel impressing elements pivotable about horizontal axes, and squeezing means for impressing the upper portion of the filled bag and comprising downwardly movable pressing strips which are associated with the impressing elements, the pressing strips being offset in relation to the moved together impressing elements, once the impressing elements have been moved together being movable towards upper portions of the bag walls shaped by the impressing elements, and being lowerable to apply the bag walls against the filled contents, the bag, at least while the impressing elements are moving towards each other, being supported on a conveyor which is movable towards the impressing elements.

2. Apparatus according to claim 1, in which one of the pressing strips is provided on both sides of each impressing element and each pressing strip has its own drive associated with it.

3. Apparatus according to claim 2, in which the drive for each pressing strip comprises a piston-cylinder unit.

4. Apparatus according to claim 2 or claim 3, in which the drives for the pressing strips are disposed on the levers which carry the impressing elements.

5. Apparatus for filling and sealing open bags by means of a filler nozzle to which the bag to be filled is applied, the apparatus comprising two mutually parallel impressing elements pivotable about horizontal axes and squeezing means for impressing the upper portion of the filled bag and comprising at least one vertically movable suction nozzle which can be connected to a suction source and is associated with the impressing elements, the suction nozzle being introduceable, after the impressing elements have been moved, into a space within the bag above the filling contents and defined by the bag walls, to evacuate the space and apply the bag walls against the filled contents, at least during evacuation of the space the bag being supported on a conveyor which is movable towards the suction nozzle.

6. Apparatus according to claim 5, in which the suction nozzle is slit shaped.

7. Apparatus according to claim 6, in which recesses are provided in the impressing elements on their mutually facing sides, to form an opening into which the slit-shaped suction nozzle can be inserted.

8. Apparatus according to any one of the preceding claims, in which the impressing elements are plate-shaped and extend substantially over the entire width of the bag.

9. Apparatus according to any one of the preceding claims, in which the impressing elements are disposed beneath a carriage which conveys a filled bag.

10. Apparatus according to any one of the preceding claims, in which the impressing elements are disposed on angled levers and one of the angled levers which is at the front in the direction of approach of the bag carries conveyor rollers which can be applied against a belt drive in order to transport the bag into sealing means.

11. Apparatus for filling and sealing open bags substantially as hereinbefore described and illustrated with reference to Figs. 1 to 3 or Fig. 4 of the accompanying drawings.