METHOD AND SYSTEM FOR AUTOMATICALLY PACKAGING COMMINUTED SILICON

Abstract

A method of automatic packing of comminuted silicon includes providing an inner bag in a first shaping vessel, spreading out an opening of the inner bag and positioning the opening above a lip of a first filling funnel of a filling unit, and filling the inner bag with comminuted silicon. The comminuted silicon passes through the filling funnel into the inner bag. The inner bag is welded in a welding unit. The opening of the inner bag is folded together by inward folding of two opposite inner bag sides such that two inner bag edges formed by the folding-together are opposite and parallel to one another and form a fold with a channel. A vacuum welder is applied to the fold and welds the inner bag. The inner bag is transferred into an outer bag. The outer bag is welded.

Claims

1-15. (canceled)

16. A method of automatic packing of comminuted silicon, comprising the steps of a) providing an inner bag in a first shaping vessel; b) spreading out an opening of the inner bag and positioning the opening above a lip of a first filling funnel of a filling unit; c) filling the inner bag with comminuted silicon, with the comminuted silicon passing through the filling funnel into the inner bag; d) welding the inner bag in a welding unit, wherein the opening of the inner bag is folded together by inward folding of two opposite inner bag sides such that two inner bag edges formed by the folding-together are opposite and parallel to one another and form a fold with a channel, and a vacuum welder applied to the fold from outside sucks air out of the inner bag through the channel and welds the inner bag; e) transferring the inner bag into an outer bag, wherein the outer bag is provided in a second shaping vessel, an opening of the outer bag is spread out and the inner bag is transferred into the outer bag; and f) welding the outer bag.

17. The method as claimed in claim 16, wherein the two edge lengths of a rectangular base area of the outer bag are each longer by 3% to 35% than the two side lengths of a rectangular base area of the inner bag.

18. The method as claimed in claim 16, wherein the opening is spread out in steps b) and/or e) by spreading fingers that dip into the bag.

19. The method as claimed in claim 16, wherein the inner bag and/or the outer bag is/are shaped before the opening is spread out.

20. The method as claimed in claim 19, wherein the shaping comprises pulling the inner bag and/or the outer bag apart by means of vacuum grips.

21. The method as claimed in claim 16, wherein, after the folding-in and before the welding in step d), a section of the fold is removed.

22. The method as claimed in claim 16, wherein the channel has a width of 1 to 20 mm, preferably of 1.5 to 10 mm, more preferably of 2 to 5 mm.

23. The method as claimed in claim 16, wherein, for transfer of the inner bag into the outer bag in step e), the inner bag is surrounded by a transport sleeve to maintain its shape.

24. The method as claimed in claim 16, wherein, for transfer of the inner bag into the outer bag in step e), the spread-out opening of the outer bag is run over a lip of a second filling funnel.

25. The method as claimed in claim 16, wherein, after the inner bag has been transferred in step e), the fold of the inner bag is turned over.

26. The method as claimed in claim 16, wherein the welding of the outer bag is effected analogously to step d).

27. The method as claimed in claim 16, comprising, as step g), a transfer of the outer bag into a transport container.

28. A system for automatic packing of silicon, comprising at least one shaping vessel for an inner bag; at least one shaping vessel for an outer bag; at least one conveying unit for movement of the shaping vessels; at least one device for spreading out an opening of the inner bag and/or an opening of the outer bag; at least one filling unit for filling the inner bag with comminuted silicon; at least one welding unit for welding the inner bag and optionally the outer bag; comprising means of inward folding of the opening so as to form a fold with a channel; and a vacuum welder which is placed onto the inner bag or optionally the outer bag from the outside; at least one gripper arm for moving the inner bag; and optionally at least one further welding unit for welding the outer bag.

29. The system as claimed in claim 28, comprising a transport sleeve by which the inner bag may be surrounded to maintain its shape.

30. The system as claimed in claim 28, comprising a cutting device for partial removal of the fold.

Description

[0074] FIG. 1 shows an inner bag in a shaping vessel.

[0075] FIG. 2A,B show an inner bag with spread-out opening.

[0076] FIG. 3 shows the inner bag with filling funnel.

[0077] FIG. 4A,B,C show the inward folding of the inner bag.

[0078] FIG. 5A,B show the welding of the inner bag.

[0079] FIG. 6 shows a welded inner bag.

[0080] FIG. 7A,B show the use of a transport sleeve.

[0081] FIG. 8 shows a welded outer bag.

LIST OF REFERENCE NUMERALS

[0082] 10 upright inner bag [0083] 12 opening [0084] 13 fold of the inner bag [0085] 14A bag side [0086] 14B bag side [0087] 15A inner edge of bag [0088] 15B inner edge of bag [0089] 16 channel [0090] 17 upper end of fold [0091] 20 first shaping vessel [0092] 22 base area of the first shaping vessel [0093] 23 base area of the second shaping vessel [0094] 24 second shaping vessel [0095] 30 spreading fingers [0096] 32 filling funnel [0097] 33 lip [0098] 40 shaping bars [0099] 42 shaping fingers [0100] 50 welding unit [0101] 51 shaping jaw [0102] 52 upper sealing lip [0103] 53 lower sealing lip [0104] 54 vacuum chamber [0105] 56 cutting device [0106] 58 heating wire [0107] 59 welding wire [0108] 60 transport box [0109] 61 arrow for indication of a movement [0110] 70 upright outer bag [0111] 72 opening [0112] 73 fold of the outer bag [0113] 80 silicon chunk

[0114] FIG. 1 shows an upright inner bag 10 made of LDPE that has an opening 12 and is disposed in a first shaping vessel 20 made of polypropylene (method step a)). The upright inner bag 10 has a square base area that corresponds to the likewise square internal base area 22 of the first shaping vessel 20. The upright inner bag 10 has been produced from a gusseted tubular film immediately before commencement of the method. On account of the folding of the starting material, the opposite bag sides 14A, 14B are each at a slight angle.

[0115] FIG. 2A shows the upright inner bag 10, with four spreading fingers 30 inserted into the opening 12 thereof, in order to stretch it out. The spreading fingers 30 are part of the filling unit, which is not shown for reasons of clarity. The spread-out opening 12 after the opening-out of the spreading fingers 30 is shown in FIG. 2B (method step b)).

[0116] FIG. 3 shows the upright inner bag 10 with its opening 12 spread out by the spreading fingers 30, into which a lip 33 of a filling funnel 32 dips without touching the upright inner bag 10 (method step b)). The filling funnel 32, like the spreading fingers 30, is part of the filling unit which is not shown.

[0117] FIG. 4A shows the upright inner bag 10 after filling with comminuted silicon. For the folding-together and closing of the opening 12, four shaping fingers 42 enter the bag 10. These shaping fingers 42 may be required when the opening 12 has closed too far after the filling. Two shaping bars 40 have approached the opposite sides of the bag 14A, 14B. The shaping bars 40 and the shaping fingers 42 are part of the welding unit which is not shown.

[0118] In FIG. 4B, the shaping bars 40 have moved together and the sides of the bag 14A, 14B have been folded in. As a result, parallel opposite inner edges of the bag 15A, 15B (cf. FIG. 4C) and a fold 13 have formed. The inner edges of the bag 15A, 15B form a channel 16 that runs through the fold, with the width of the channel 13 corresponding roughly to the distance between the two shaping bars 40. The shaping fingers 42 can facilitate the formation of the fold 13 by virtue of their spacing.

[0119] FIG. 4C shows the upright inner bag 10 after the shaping bars 40 and the shaping fingers 42 have been removed. The channel 16 shaped by the inner edges of the bag 15A, 15B, which are not touching, is indicated by dotted lines for illustration.

[0120] FIG. 5A shows the upright inner bag 10 according to FIG. 4C in a side view with a welding unit 50. This comprises two shaping jaws 51, which approach the fold 13 to the left and right. Each shaping jaw 51 comprises an upper sealing lip 52 and a lower sealing lip 53 that can form a vacuum chamber 54 when the welding unit 50 is placed onto the fold 13. The welding unit 50 contains a cutting device 56 for removal of a section of the fold 13. The removal is necessary in order that the vacuum chamber 54 can form on the fold 13 after the shaping jaws 51 have been attached and can suck the air out of the upright inner bag 10 through the channel 16 (cf. FIG. 4C). It is possible to dispense with removal of a section of the fold 13 when the welding unit 50 begins at the upper end 17 (not shown).

[0121] FIG. 5B shows the bag 10 shortly after welding. The cutting device 56 has removed a section of the fold 13. The heating wire 58 has provided the fold 13 with a weld seam 59.

[0122] A welded upright inner bag 10 is shown in FIG. 6. The first shaping vessel 20 is not shown here. The bag is typically a 5 kg bag with square base area. A typical value of l, b is 150 mm.

[0123] FIG. 7A shows the welded upright inner bag 10 in the first shaping vessel 20, with an approaching transport sleeve 60. The transport sleeve 60 has the same clear dimensions as the first shaping vessel 20 and may be placed onto the latter. The upright inner bag 10 may, for example by means of a gripper arm, which grips the fold 13 through the transport sleeve 60 (not shown), be introduced into the transport sleeve 60 by lifting. The raising of the upright inner bag 10 and the lowering of the transport sleeve 60 are indicated by the movement arrows 61.

[0124] In FIG. 7B, the transport sleeve 60 is shown together with the welded upright inner bag 10 and a second shaping vessel 24 with an upright outer bag 70 disposed therein. The opening 72 of the upright outer bag 70 is spread open with spreading fingers 30. The upright outer bag 70 has a square base area corresponding to the square internal base area 23 of the second shaping vessel 24. The base area 23 is about 13% larger than the base area 22. The transport sleeve 60, the spread-out opening 72 of the upright outer bag 70 and the second shaping vessel 24 are arranged in a perpendicular line one on top of another. For instance, the upright inner bag 10 may be lowered into the upright outer bag 70, for example by means of a gripper arm (not shown), without any resultant bulging of the upright inner bag 10.

[0125] FIG. 8 shows the cross section of the upright outer bag 70 with the upright inner bag 10 present therein and filled with silicon chunks 80. Both the fold 13 of the upright inner bag 10 and the fold 73 of the upright outer bag 70 are folded in. A typical height of the 5 kg bag is 220 to 240 mm. As a result, it is possible to achieve an optimal pack size in an outer packing.

[0126] On account of the use of one shaping vessel each for inner bag and outer bag, it is possible to achieve a very small pack size since bulges during and after the filling are reduced to a minimum.