GB2222564A

GB2222564A - Filling open containers, e.g. big sacks

Info

Publication number: GB2222564A
Application number: GB8917902A
Authority: GB
Inventors: Hermann Thueer
Original assignee: Haver and Boecker OHG
Current assignee: Haver and Boecker OHG
Priority date: 1988-08-05
Filing date: 1989-08-04
Publication date: 1990-03-14
Anticipated expiration: 2009-08-04
Also published as: GB8917902D0; NO175049C; NL8901808A; FR2635080A1; DE8810027U1; DD292192A5; NO893159L; GB2222564B; FR2635080B3; NO175049B; NO893159D0

Abstract

Apparatus for filling large open sacks, for example, with a capacity of 500 kg, is equipped with a compaction worm disposed in a double-walled hollow cylinder (12). As the sack is filled it is so lowered that the discharge end of the worm conveyer is maintained within the material being filled. To prevent material continuing to trickle through after the conveyor has been switched off, a closure means (19) is provided which comprises an annular upper closure part (20) and an annular closure part (21). As a result of a rotary and upward movement produced by means of a member (27) passing through a hollow shaft (26) and connected to annular part (21), part (21) can be moved to a closure position. Each closure part (20, 21) is provided with an equal number of radially extending support spokes (23) for flexibly deformable closure plates (22). The radially extending edges of each closure plate (22) are fixed on the supporting spokes (23) of the upper closure part (20) and the lower closure part (21). In the filling position, the closure plates (22) are vertical while in the closure position they are substantially horizontal and overlap in order to provide a tight seal. <IMAGE>

Description

APPARATUS FOR FILLING OPEN CONTAINERS The invention relates to apparatus for filling open containers, such as large open sacks, and having a vertically disposed worm conveyer to transport material to be filled into the sacks from a silo and into the container while at the same time exerting a compaction effect.

Such apparatus can be used for example for filling large opentop plastics sacks with a volume of for example 500 kg. Usually, the material is in a powdered form. The worm transporting the contents is situated within a double-walled hollow cylinder, the inner wall of which has a plurality of openings so that the material being conveyed by the worm can be compressed by a vacuum.

While a sack is being filled, the level of the contents is constantly scanned and the sack is lowered while keeping the discharge end of the worm container still situated within the material being filled. The filling process is controlled by a weighing means which stops the worm when the desired weight is attained.

A disadvantage of this per se quite successful filling arrangement is that after the worm conveyer has been switched off, material still trickles through since an annular passage through the conveyer is open at the delivery end.

According to the invention there is provided apparatus for filling open containers and having a vertically disposed worm conveyer to transport material from a silo and into a container while at the same time exerting a compaction effect,in which the apparatus includes, within the contours of the worm conveyer, a closure device comprising an annular upper part and an annular lower part which can be moved between a filling position and a closed position by a relative rotary movement and a simultaneous relative height adjustment, each closure part is provided with an equal number of radially extending support webs for a corresponding quantity of flexibly deformable closure plates and the radially extending edges of each of the closure plates are so fixed on the supporting webs of the upper closure part and the lower closure part that when the closure parts are in the filling position the closure plates are vertical while in the closed position they are substantially horizontal with the radially extending marginal zones of adjacent ones of the closure plates mutually overlapping.

Thus the annular conveyer passage is closed off when the filling process is completed without any need to use laterally disposed closure parts, such as flap valves, rotary slide valves or cones.

The annular conveyer passage is closed by segmentally shaped closure plates which are all within the contours of the worm conveyer.

In the filling position, they are vertical and are thus orientated in the direction of through-flow of the material with which the containers are to be filled, so that the cross-section of the segmented worm passage is only insignificantly reduced. In the closed position, the outer and inner contours of the closure plates form concentric circles which correspond to the two diameters of the annular conveyer passage.

From the technically functional point of view, in the closed position the individual plates can be regarded as a sealing plate which has been pushed into the conveyer passage. The reciprocal overlapping of the radially extending edges ensures that there are no leaky joints.

Preferably the upper closure part is fixed on the housing of the worm conveyer which is constructed as a hollow cylinder, in which case the lower closure part is adjustable in height and can be rotated by means of a drive. As a result, the necessary relative movement between the upper and lower closure parts can be achieved in a particularly simple way. Furthermore, the movable lower part is moved away from the material with which the container has been filled. Also so that no drive parts project laterally beyond the worm conveyer, the lower part is expediently likewise within the inner contours of the worm conveyer and is equipped with a linkage which is guided through a hollow shaft of the worm conveyer and coupled to the movable lower closure part.

The angle of rotation of the movable lower closure part is governed by the number of supporting webs on the upper and lower closure parts. So that this angle does not become too great, it is expedient for the upper and lower closure parts each to comprise eight supporting webs.

The angle of rotation of the movable lower closure part will then be 450. This angle can be achieved by simple drive units.

The invention is diagrammatically illustrated by way of example in the accompanying drawings; in which: Figure 1 is a plan view of apparatus for filling open containers according to the invention; Figure 2 shows a discharge end of a worm conveyer of the apparatus of Figure 1 in a filling position of a closure arrangement; Figure 3 is a plan view corresponding to Figure 2 but showing only the closure arrangement; Figure 4 is a view corresponding to Figure 2 but in a midway position of a movable lower closure part; Figure 5 is a view corresponding to Figure 2 but in the closed position of the closure arrangement; and Figure 6 is a detail in a sectional view showing fixing of closure plates by means of supporting webs.

Referring to the drawings, a worm conveyer 10 has a conveyer screw 11 disposed in a housing 12 which is constructed as a hollow cylinder. The conveyer screw 11 is driven by a motor 13 in order to feed materials from a silo 14 (only indicated in the drawings) into a container 15 which is illustrated by the dash-dotted lines. A holder 16 for the container 15 is so lowered during the filling process that the bottom discharge end of the worm conveyer 10 is maintained at a constant position in relation to the height to which the container has been filled. The bottom extreme position of the holder 16 is designated 16' while that of the container in this position is designated 15', these are shown in dash-dotted lines. Preferred containers are large plastics sacks. Control of the filling process is effected by two per se known weighing cells 17, 18.Associated with the discharge end of the worm conveyer 10 is a closure arrangement 19 which is explained in greater detail hereinafter with reference to Figures 2 to 6. The closure arrangement 19 comprises an upper closure part 20 which is rigidly connected to the bottom edge of the housing 10, a movable lower closure part 21 and (in the embodiment illustrated) eight closure plates 22 formed of an elastically deformable material such as for example rubber or a rubber-like plastics material. The upper closure part 20 and the lower closure part 21 each mount eight supporting webs 23 to be explained in greater detail hereinafter with reference to Figure 6 and which extend at angular intervals of 450 from each other from a central point towards the outer edge, in stellate fashion. As the drawings show, the upper and lower closure parts each comprise an outer ring 24, 25 which is aligned with the housing 12 of the worm conveyer 10. The supporting webs 23 of the upper closure part 20 and of the lower closure part 21 are situated above one another in the filling position which is shown in Figure 2. The closure plates 22 are orientated vertically in the direction of through-flow of the contents. Thus, almost the entire cross-section of the closure means 19 is available to the material with which the bags are to be filled.

A shaft carrying the screw 11 of the worm conveyer 10 is a hollow shaft 26. Passing through the hollow shaft 26 and only indicated in the drawings is a linkage 27, the free end of which is rigidly connected to the lower closure part 21. The other end of the linkage 27 is coupled to a drive 28 which is so designed that the linkage 27 can be rotated and simultaneously moved in a vertical direction. The lower closure part therefore follows the movement of the linkage 27. The drive 28 may for example be a correspondingly designed pneumatic cylinder. If by means of the drive 28 the lower closure part 21 is moved towards the upper closure part 20, then the closure plates 22 are moved into a substantially horizontal position and form a closure barrier to seal off the cross-section of the closure means 19.In this closed position, adjacent supporting webs which were previously offset by the angle of rotation are aligned as Figure 5 shows. Even in such a position, there is an overlap of the radially extending edges which is needed for sealing tightness but, in contrast to the view shown in Figure 5, an offset can be brought about between the supporting webs in order to increase the overlap. By a movement in the opposite direction, the closure means 19 can be restored to the filling position shown in Figure 2. The upper closure part 20 still comprises a central hub 29 for mounting of the conveyer screw 11.

Figure 6 shows the connection of a closure plate to a supporting web 23. As shown, the supporting web comprises a half round screw which is screwed from the outside into the hub 29 of the upper closure part or the lower closure part. For this purpose, the hub 29 includes appropriate screw-threaded bores. The hub of the lower closure part 21 is so designed that the linkage 27 can be rigidly attached to it. The radially extending edges of the closure plates 22 are of loop-shaped design in order to form a bore through which the screw can pass.

However, other types of fixing, for example by clamping, are possible.

Since the shape of the closure plates 22 when laid flat must be similar to the shape created by the segments formed by the supporting webs 23, the supporting webs 23 of the movable lower closure part 21 are inclined to the horizontal in relation to the filling position.

Consequently, the outer arc dimension of each closure plate 22 is greater than the inner dimension.

As can be seen from the drawings, neither the closure means 19 nor the drive 28 required for it, with the linkage 27, has any parts which project beyond the contours of the worm conveyer 10. By reason of the closure plates 22 of the closure means 19, it is possible for actuation to take place from within.

Claims

1. Apparatus for filling open containers and having a vertically disposed worm conveyer to transport material from a silo and into a container while at the same time exerting a compaction effect, in which the apparatus includes, within the contours of the worm conveyer, a closure device comprising an annular upper part and an annular lower part which can be moved between a filling position and a closed position by a relative rotary movement and a simultaneous relative height adjustment, each closure part is provided with an equal number of radially extending support webs for a corresponding quantity of flexibly deformable closure plates and the radially extending edges of each of the closure plates are so fixed on the supporting webs of the upper closure part and the lower closure part that when the closure parts are in the filling position the closure plates are vertical while in the closed position they are substantially horizontal with the radially extending marginal zones of adjacent ones of the closure plates mutually overlapping.

2. Apparatus according to Claim 1, in which the upper closure part is fixed on a housing of the worm conveyer which is constructed as a hollow cylinder and the lower closure part is adjustable in height and is rotatable by means of a drive with respect to the upper closure part.

3. Apparatus according to Claim 2, in which the drive is situated above and within the inner contours of the worm conveyer, is equipped with a linkage extending through a hollow shaft of the worm conveyer and is coupled to the movable lower closure part.

4. Apparatus according to Claim 1, in which the upper and lower closure parts mount a plurality of supporting webs disposed at equal angular intervals from one another.

5. Apparatus according to Claim 4, in which there are eight supporting webs.

6. Apparatus according to Claim 4 or Claim 5, in which the supporting webs of the lower closure part are inclined to the horizontal so that the inner ends are higher than the outer ends.

7. Apparatus according to any one of Claims 14 to 6, in which the upper closure part and the lower closure part each have an outer ring corresponding to the diameter of the housing and a central hub.

8. Apparatus according to any one of Claims 7, in which each supporting web is constructed as a screw which passes through the outer ring of the upper closure part or the lower closure part and is screwed into the hub and the radially extending edges of each closure plate are formed as loops to define passages through which the screw can pass.

9. Apparatus for filling open containers substantially as hereinbefore described and illustrated with reference to the accompanying drawings.