Method and system for automatically packaging pulverized silicon

Abstract

The invention relates to a method for automatically packaging pulverized silicon (bulk silicon), comprising the following steps: a) providing an inner bag in a first shaping container; b) unfolding the opening of the inner bag and positioning the opening above the lip of a first filling funnel of a filling unit; c) filling the inner bag with pulverized silicon, which enters the inner bag through the filling funnel; d) welding the inner bag in a welding unit, the opening of the inner bag is folded together by folding two opposite inner bag sides inwards, such that the two inner bag edges formed by the folding together are opposite and parallel to each other and form a fold with a channel, and a vacuum welder applied from the outside to the fold sucks air out of the inner bag through the channel and welds the inner bag; e) transferring the inner bag into an outer bag, the outer bag is provided in a second shaping container, the opening of the outer bag is unfolded and the inner bag is transferred into the outer bag; f) welding the outer bag.

Description

Technical Field

[0001] The present invention relates to a method and a device for automatically packaging crushed silicon. Background Art

[0002] Polycrystalline silicon (polysilicon) is typically produced using the Siemens process (chemical vapor deposition). Polycrystalline silicon is the starting material for the production of single-crystalline silicon, which can be produced, for example, using the Czochralski process. Alternatively, polycrystalline silicon is required for the production of multicrystalline silicon (e.g., using the block casting process). For both processes, the rod-shaped polycrystalline silicon after the Siemens process must be comminuted into blocks.

[0003] Because contamination can cause dislocation defects (one-dimensional defects) and stacking defects (two-dimensional defects) in the crystal structure, crushed silicon should be shipped in low-contamination packaging. Typically, packaging occurs in flat or double-film plastic bags that are sealed after filling. For even more efficient shipping, the bags are arranged in outer packaging (usually cardboard boxes) with varying quantities of items. These can then be stacked on conventional pallets and transferred to containers.

[0004] Crushed polysilicon (chunk polysilicon) is typically a sharp-edged, non-free-flowing, lumpy material. Depending on the size of the chunk, a single chunk can weigh up to 750g. Therefore, when packaging, it is particularly important to ensure that no tears occur during the filling of the plastic bag. Double-film bags can reduce the risk of tears.

[0005] In addition to tears caused by the filling process, the sealing of plastic bags can also be a source of contamination. Typically, plastic bags are at least partially emptied before sealing to ensure a tighter bag size. To this end, a suction probe is often introduced into the bag to suck out the air, and the bag is welded directly after the suction probe is removed. Because any material introduced into the bag from the outside is likely to contain impurities, welding with a suction probe is a potential source of contamination.

[0006] Silicon is usually packaged in at least a partially automated manner. Often, constituent steps of the packaging process are still performed manually, as full automation does not appear to be economically feasible in view of the high purity requirements.

[0007] WO 2016 / 188893 A1 describes a method for packaging polysilicon, wherein crushed polysilicon to be packaged is provided on a processing tray, which has previously undergone a cleaning step. To transfer the polysilicon into flat plastic bags, the processing tray and the plastic bags are fixed to a filling unit, wherein rotation of the filling unit causes the polysilicon to slide into the plastic bags.

[0008] EP 3 199 472 A1 describes filling a stand-up film bag made of polyethylene (PE) with polysilicon, wherein the bag is placed in a frame. The frame is intended to prevent the bag from bulging during filling. After filling, the bag is optionally transferred to an outer PE bag, where the chemical properties of the PE in the two bags are matched, allowing them to slide relative to each other as much as possible. The disadvantage here is that the stand-up bag bulges during transfer to the outer bag, which results in the outer bag being much larger than the stand-up bag.

[0009] EP 2 030 905 A2 describes a first stand-up bag made of plastic for filling polysilicon. This first stand-up bag is made of a tubular film folded over to form a rectangular upright surface with a fold. After filling, the first stand-up bag is inserted into a second, larger stand-up bag of the same type, with the fold of the first stand-up bag rotated 90° relative to the fold of the second stand-up bag. This often results in undesirable bulging of the first stand-up bag. Summary of the Invention

[0010] This problem gave rise to the object of the present invention, namely to provide a fully automatic packaging method for bulk silicon which meets the purity requirements for bulk silicon and also offers economic advantages.

[0011] This object is achieved by a method for automatically packaging crushed silicon (silicon chunks), the method comprising the following steps:

[0012] a) providing an inner bag in a first shaped container,

[0013] b) unfolding the opening of the inner bag and positioning the opening above the lip of the first filling funnel of the filling unit,

[0014] c) filling the inner bag with crushed silicon, wherein the crushed silicon enters the inner bag through a filling funnel,

[0015] d) welding the inner bag in a welding unit, wherein the opening of the inner bag is folded together by folding two opposing inner bag side surfaces inwardly so that the two inner bag edges formed by folding together are opposite and parallel to each other and form a folded portion having a channel, and a vacuum welder applied from the outside to the folded portion sucks air out of the inner bag through the channel and welds the inner bag,

[0016] e) transferring the inner bag into the outer bag, wherein the outer bag is provided in a second shaped container, the opening of the outer bag is unfolded and the inner bag is transferred into the outer bag,

[0017] f) Weld the outer bag.

[0018] The inner bag and / or outer bag are preferably stand-up bags. Stand-up bags are generally characterized in that they stand upright before and / or after filling. The inner bag and / or outer bag preferably have rectangular stand-up surfaces, in particular square stand-up surfaces.

[0019] The two sides of the rectangular upright surface or bottom area of ​​the outer bag are each 3% to 35% longer than the two sides of the rectangular upright surface or bottom area of ​​the inner bag, preferably 4% to 30% longer, more preferably 5% to 20% longer.

[0020] For example, in the filled state, an upright inner bag for 5 kg of silicon may have a length a in the range of 10 to 20 cm, a width b in the range of 10 to 20 cm and a height h in the range of 10 to 50 cm, where a and b correspond to the side lengths of the upright surface of the bag.

[0021] A typical 5kg stand-up inner bag may have a square stand-up surface with sides a and b of 15 cm. A corresponding typical stand-up outer bag may have a square stand-up surface with sides a and b of 17 cm. The stand-up surface of the outer bag is therefore 27% larger.

[0022] Preferably, the inner bag and / or outer bag are made of a polymer film. The polymer may be PE (e.g., LDPE (low density), LLDPE (linear low density), HDPE (high density)), polyethylene terephthalate (PET), polyamide (PA), or polypropylene (PP). More preferably, the inner bag and outer bag are made of LDPE. Furthermore, the composite film may be a two-layer or multi-layer composite film. The thickness of the polymer film or composite film is typically in the range of 10 to 600 μm, preferably 50 to 450 μm, and more preferably 100 to 330 μm. The inner bag and outer bag may differ in film thickness. It may be preferred that the outer bag be made of a more durable material than the inner bag.

[0023] Preferably, the inner and / or outer bags are automatically pre-formed from high-cleanliness tubular film, centerfold film, or gusseted tubular film directly before being placed in the first or second shaping container. For this purpose, a film section of appropriate length is cut and welded at one end to form the bottom of the bag. The bag can then be opened with a vacuum clamp, shaped by passing through an incoming shaping tube, and then transferred to the shaping container.

[0024] The first and / or second shaped container preferably has the same bottom area as the inner or outer bag. The bottom area of ​​the shaped container is optionally 10% larger than that of the corresponding bag to facilitate bag handling. The height of the first shaped container preferably corresponds at least to the filling height of the inner bag. This ensures that it does not deform during filling. The same applies to the second shaped container. The shaped container is preferably made of an antistatic material, particularly plastic, such as polypropylene. It is also possible to manufacture it from metal, such as aluminum. It may optionally have a silicone coating to prevent contamination.

[0025] The first shaped container is preferably on or connected to a conveyor. The conveyor can be, for example, a conveyor belt, a track system, or a robotic arm. The conveyor can move the shaped container between filling stations (e.g., filling units, welding units).

[0026] The opening of the inner bag is preferably positioned above the lip of the first filling funnel of the filling unit by the conveying device.However, it can also be the case that the filling unit is moved towards the opening of the inner bag.

[0027] The lip preferably enters the opening of the inner bag without contact. A typical entry depth may be 1 to 5 cm. The distance between the lip and the inner bag is preferably 0.5 to 10 mm, more preferably 1 to 5 mm.

[0028] To allow the lip to enter the opening, the opening is preferably opened by spreading fingers that enter the inner bag. The spreading fingers can be part of the filling unit. However, a separate device for opening can also be provided, which can be moved together with the transport container. This particularly includes four spreading fingers that open the rectangular opening.

[0029] Since the opening is usually not fully widened after the inner bag is provided, expansion is required.

[0030] In some cases, it may even be preferred that the inner bag is shaped before unfolding. This is preferably done during provision, for example by introducing some kind of spike or bag shaping tube into the bag.

[0031] However, more preferably, shaping comprises pulling the inner bag open with the aid of vacuum clamps. The vacuum clamps can be vacuum strips or vacuum cups placed from the outside. The advantage of this variant is the reduced risk of contamination.

[0032] The inner bag can be filled by the method according to WO 2016 / 188893 A1. In this case, the crushed silicon arranged in the processing disk slides into the inner bag by the rotation of the filling unit.

[0033] The inner bag is preferably filled with chunk silicon of one chunk size grade. In particular, it is chunk polysilicon, i.e., crushed polysilicon. In principle, the inner bag can also be filled with chunk silicon from more than one chunk size grade. In particular, chunk silicon from size grades 0 to 4 is allocated.

[0034] Chunk size classes 0 to 4 (CS0 to CS4) are defined by the grain size of the chunk, which is defined as the longest distance between two points on the surface of the silicon chunk. Chunk size classes consist of fractions with the following grain size ranges:

[0035] CS0: 0.1 to 9 mm

[0036] CS1: 1 to 18 mm

[0037] CS2: 5 to 50mm

[0038] CS3: 20 to 65mm

[0039] CS4: 35 to 150mm

[0040] The silicon chunks can be sorted with the aid of a mesh screen, wherein the edge length of the square grid corresponds to the upper limit of the CS. The CS preferably contains at least 90% by weight of chunks within the specified size range.

[0041] Preferably, the shaped container with the filled inner bag is fed into a welding unit for welding.

[0042] To achieve the most compact packaging dimensions, standard practice in silicon packaging is to at least partially remove the air from the film bag before welding. Applying a full vacuum is less common, as this increases the risk of tearing. Air is typically removed using a suction probe that is introduced into the bag and then removed shortly before welding. As already mentioned, in silicon packaging, even the brief introduction of foreign matter into the bag must be strictly avoided.

[0043] It has now been found that a channel formed by a specific inward folding of two opposing inner surfaces of the bag can act as an air channel for suction, thereby eliminating the need for a suction probe. In Figure 4 an inner bag with folds and channels that has been folded together for welding is shown.

[0044] To facilitate folding, four shaped fingers enter the opening, which has optionally been previously stretched open by a vacuum clamp or opened under tension.

[0045] The parallel, opposing inner edges of the bag are preferably formed by two shaping rods. These shaping rods can be evenly moved toward each other from the outside of the bag. In this way, they fold the two opposing inner surfaces of the bag inward and form the opposing inner edges of the bag, thereby forming a channel. The vacuum welder can then be moved toward the resulting fold.

[0046] The vacuum welder preferably includes two sizing jaws, each containing a heating wire that can be sheathed in a non-metallic material such as polytetrafluoroethylene. Each sizing jaw is applied to one side of the fold. Preferably, the sealing lip surrounding the sizing jaw with the welding wire forms a vacuum chamber after application, allowing air to be sucked out through the channel. Alternatively, the fold and the sizing jaws can be transferred to the vacuum chamber for extraction.

[0047] In a preferred embodiment, a portion of the fold is removed before welding. This can be accomplished using an automated cutting device, which can be part of the welding unit. This simplifies the application of the vacuum and reduces the size and weight of the package. In principle, the removal can also be performed after welding.

[0048] The channel preferably has a width of 1 to 15 mm, more preferably 1.5 to 10 mm, in particular 2 to 5 mm. The width of the channel is preferably 0.5 to 5%, in particular 1 to 3%, of the length of the long side of the bottom area forming the inner bag.

[0049] After the inner bag has been welded, it is transferred to the outer bag. During the welding of the inner bag, the outer bag is preferably already arranged in the second shaped container. The second shaped container is also preferably located on a conveying device, for which reference can be made to the description of the first shaped container.

[0050] With regard to the unfolding and any necessary shaping of the outer bag, reference can also be made to the above description.

[0051] The second shaping container is preferably located below the welding unit. The inner bag can then be removed from the first shaping container and transferred to the outer bag using the gripping arm. Alternatively, the inner bag can be held by the gripping arm while the first shaping container is moved downward and then sideways. Transfer can be achieved by lowering the inner bag into the outer bag or by raising the outer bag.

[0052] To facilitate transfer of the inner bag into the outer bag, the outer bag's opening can extend beyond the lip of the second filling funnel. For the distance between the lip and its immersion depth, refer to the details above. The second filling funnel generally serves as a kind of frame, upon which the inner bag can be lowered into the outer bag. This prevents a bulging inner bag from becoming lodged in the outer bag's opening.

[0053] In a preferred embodiment, in order to transfer the inner bag to the outer bag, the inner bag is surrounded by a transfer sleeve to maintain its shape (to prevent bulging). The transfer sleeve preferably has the same net dimensions as the first shaped container. For illustration, the transfer sleeve can be described as the first shaped container without a bottom.

[0054] Preferably, after the inner bag has been welded, the transfer sleeve is positioned above the inner bag so that the net dimensions of the first shaped container are substantially identical to those of the transfer sleeve. The inner bag is then transferred (lifted) into the transfer sleeve by means of a clamping arm. The two can then be moved together over the opening of the outer bag or optionally over the second filling hopper, and the inner bag lowered. More preferably, for this purpose, the transfer sleeve together with the inner bag, optionally the second filling hopper, and the second shaped container together with the outer bag are arranged one above the other in a vertical line.

[0055] The use of a transfer sleeve makes it possible to precisely match the dimensions of the inner and outer bag. Previously, the dimensions of the outer bag were chosen so that a deformed (bulging) inner bag could also slide in without resistance. This tolerance is no longer necessary, which results in considerable material savings.

[0056] Preferably, after the inner bag is transferred into the outer bag, the upright fold of the inner bag is folded. More preferably, the fold is clamped between the inner bag and the outer bag. This can be performed, for example, by means of an automatically movable probe.

[0057] The welding of the outer bag is preferably carried out in the same manner as the welding of the inner bag. For this purpose, additional welding units can be provided to increase production volume.

[0058] As a further step g), the welded outer bags are optionally then transferred to a transport container. The transport container is preferably a cardboard box, in which there is preferably space for six welded outer bags. The weight of the crushed silicon here is especially 5 kg (5 kg bag).

[0059] The entire fully automatic packaging process is preferably monitored by a camera, so that manual inspection can be dispensed with.

[0060] Another aspect of the present invention relates to a system for automatic packaging of crushed silicon, in particular a system for performing the method described above. The device comprises the following components:

[0061] - at least one first shaped container for the inner bag,

[0062] - at least one second shaped container for the outer bag,

[0063] at least one conveying unit for moving two shaped containers,

[0064] - at least one device for opening the inner bag opening and the outer bag opening,

[0065] - at least one filling unit for filling the inner bag with comminuted silicon,

[0066] at least one welding unit for welding the inner bag and optionally the outer bag, said at least one welding unit comprising means for folding the opening inwards so as to form a fold with a channel, and a vacuum welder placed on the inner bag or optionally the outer bag from the outside,

[0067] - at least one gripping arm for moving the inner bag,

[0068] - Optionally at least one further welding unit for welding the outer bag.

[0069] The system preferably includes a delivery sleeve, and the inner bag can be surrounded by the delivery sleeve to maintain its shape.

[0070] In another embodiment, it may be the case that the system, in particular the welding unit, comprises a cutting device for at least partially removing the fold.The fold may be a fold of the inner bag and the outer bag.

[0071] The means for folding the opening inwards may in particular be the profiled rod for folding.

[0072] With regard to the description of the individual components and any further components present, reference is made to the above description of the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The present invention will be described below with reference to the accompanying drawings.

[0074] Figure 1 An inner bag in a shaped container is shown.

[0075] Figure 2A , B shows an inner bag with a deployed opening.

[0076] Figure 3 An inner bag with a filling funnel is shown.

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

[0078] Figure 5A , B shows the welding of the inner bag.

[0079] Figure 6 The welded inner bag is shown.

[0080] Figure 7A , B shows the use of a transfer sleeve.

[0081] Figure 8 The welded outer bag is shown.

[0082] Reference Signs List

[0083] 10 vertical inner pockets

[0084] 12 Opening

[0085] 13 Folding Department

[0086] 14A bag side

[0087] 14B bag side

[0088] 15A Inner edge of bag

[0089] 15B Inner edge of bag

[0090] 16 channels

[0091] 17 Upper end of the folded portion

[0092] 20 First shaped container

[0093] 22 Bottom area of ​​the first shaped container

[0094] 23 Bottom area of ​​the second shaped container

[0095] 24 Second shaped container

[0096] 30 Extended Fingers

[0097] 32 Filling Funnel

[0098] 33 Lips

[0099] 40 Molding rod

[0100] 42 Shaped Fingers

[0101] 50 welding units

[0102] 51 Molded jaws

[0103] 52 Upper sealing lip

[0104] 53 Lower sealing lip

[0105] 54 Vacuum Chamber

[0106] 56 cutting device

[0107] 58 Heating Wire

[0108] 59 welding wire

[0109] 60 transport boxes

[0110] 61 Arrows used to indicate movement

[0111] 70 stand up outer pocket

[0112] 72 Opening

[0113] 73 Folding part of outer bag

[0114] 80 silicon blocks DETAILED DESCRIPTION

[0115] Figure 1 A stand-up inner bag 10 made of LDPE is shown having an opening 12 and positioned within a first shaped container 20 made of polypropylene (process step a). The stand-up inner bag 10 has a square bottom area that corresponds to the similarly square interior bottom area 22 of the first shaped container 20. Immediately prior to the process, the stand-up inner bag 10 is made from gusseted tubular film. Due to the folding of the starting material, the opposing bag sides 14A, 14B are each at a slight angle.

[0116] Figure 2A The upright inner bag 10 is shown with four spreading fingers 30 inserted into its opening 12 in order to spread it out. The spreading fingers 30 are part of the filling unit which is not shown for the sake of clarity. Figure 2B FIG. 4 shows the unfolding opening 12 after the spreading fingers 30 have been opened (method step b)).

[0117] Figure 3 The upright inner bag 10 is shown with its opening 12 spread by spreading fingers 30 and the lip 33 of the filling funnel 32 extending therein without contacting the upright inner bag 10 (method step b). The filling funnel 32, like the spreading fingers 30, is part of a filling unit (not shown).

[0118] Figure 4A The upright inner bag 10 is shown after being filled with crushed silicon. To fold the opening 12 together and seal it, four shaping fingers 42 are inserted into the upright inner bag 10. These shaping fingers 42 may be necessary if the opening 12 closes too far after filling. Two shaping rods 40 are already positioned adjacent to opposing sides 14A, 14B of the bag. The shaping rods 40 and shaping fingers 42 are part of a welding unit (not shown).

[0119] exist Figure 4B In the embodiment, the shaping bars 40 have been moved together and the sides 14A, 14B of the bag have been folded. As a result, parallel opposing inner edges 15A, 15B of the bag are formed (see FIG. Figure 4C ) and the fold 13. The inner edges 15A, 15B of the bag form a channel 16 through the fold, wherein the width of the channel 16 corresponds approximately to the distance between the two shaping bars 40. The shaping fingers 42 contribute to the formation of the fold 13 due to their spacing.

[0120] Figure 4C The upright inner bag 10 is shown after the sizing rods 40 and sizing fingers 42 have been removed. For illustration purposes, the channel 16 formed through the non-contacting inner edges 15A, 15B of the bag is indicated by a dotted line.

[0121] Figure 5A The side view shows the welding unit 50 according to Figure 4C The upright inner bag 10 comprises two shaping jaws 51 close to the fold 13 on the left and right sides. Each shaping jaw 51 comprises an upper sealing lip 52 and a lower sealing lip 53, which can form a vacuum chamber 54 when the welding unit 50 is placed on the fold 13. The welding unit 50 includes a cutting device 56 for removing a part of the fold 13. In order that the vacuum chamber 54 can be formed on the fold 13 after the shaping jaws 51 have been attached and can be opened through the channel 16 (see Figure 4C ) sucks the air out of the upright inner bag 10, which removal is necessary. When the welding unit 50 starts at the upper end 17 (not shown), a portion of the folded portion 13 can be omitted.

[0122] Figure 5B The stand-up inner bag 10 is shown shortly after welding. The cutting device 56 removes a portion of the fold 13. The heating wire 58 provides a weld 59 to the fold 13.

[0123] Figure 6 The welded upright inner bag 10 is shown in FIG. The first shaped container 20 is not shown here. The bag is typically a 5 kg bag with a square bottom area. Typical values ​​for a and b are 150 mm.

[0124] Figure 7A The welded stand-up inner bag 10 is shown in a first shaped container 20 with an approaching transfer sleeve 60. The transfer sleeve 60 has the same net dimensions as the first shaped container 20 and can be placed on the first shaped container 20. The stand-up inner bag 10 can be introduced into the transfer sleeve 60 by lifting, for example, with the aid of gripping arms (not shown) which grip the fold 13 via the transfer sleeve 60. The raising of the stand-up inner bag 10 and the lowering of the transfer sleeve 60 are indicated by movement arrows 61.

[0125] exist Figure 7B , a transfer sleeve 60 is shown together with a welded stand-up inner bag 10 and a second shaped container 24 in which a stand-up outer bag 70 is disposed. The opening 72 of the stand-up outer bag 70 is expanded with the expansion fingers 30. The stand-up outer bag 70 has a square bottom area corresponding to the square inner bottom area 23 of the second shaped container 24. The bottom area 23 is approximately 13% larger than the bottom area 22. The transfer sleeve 60, the expanded opening 72 of the stand-up outer bag 70, and the second shaped container 24 are arranged one above the other along a vertical line. For example, the stand-up inner bag 10 can be lowered into the stand-up outer bag 70, for example, by means of a clamping arm (not shown), without any resulting bulging of the stand-up inner bag 10.

[0126] Figure 8 A cross-section of a stand-up outer bag 70 is shown, with a stand-up inner bag 10 located therein and filled with silicon chunks 80. Both the fold 13 of the stand-up inner bag 10 and the fold 73 of the stand-up outer bag 70 are folded. A typical height of a 5 kg bag is 220 to 240 mm. This allows for an optimal packaging size in the outer packaging.

[0127] Since a shaped container is used for each of the inner and outer bag, very small package sizes can be achieved, as bulging during and after filling is reduced to a minimum.

Claims

1. A method for automatically packaging crushed silicon, comprising the following steps: a) providing an inner bag in a first shaped container, b) unfolding the opening of the inner bag and positioning the opening above the lip of the first filling funnel of the filling unit, c) filling the inner bag with crushed silicon, the crushed silicon entering the inner bag through the first filling funnel, d) welding the inner bag in a welding unit, wherein the opening of the inner bag is folded together by folding two opposing inner bag sides inwardly so that the two inner bag edges formed by folding together are opposite and parallel to each other and form a folded portion having a channel, and a vacuum welder applied from the outside to the folded portion 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 shaped container, the opening of the outer bag is opened and the inner bag is transferred into the outer bag, f) Welding the outer bag.

2. The method according to claim 1, characterized in that The lengths of two edges of the rectangular bottom area of ​​the outer bag are respectively 3% to 35% longer than the lengths of two sides of the rectangular bottom area of ​​the inner bag.

3. The method according to claim 1 or 2, characterized in that The opening of the inner bag is opened in step b) and / or the opening of the outer bag is opened in step e) by opening fingers inserted into the inner bag or the outer bag.

4. The method according to claim 1 or 2, characterized in that The inner bag and / or the outer bag are shaped before the opening of the inner bag and / or the opening of the outer bag are unfolded.

5. The method according to claim 4, characterized in that The shaping comprises pulling the inner bag and / or the outer bag open by means of a vacuum clamp.

6. The method according to claim 1 or 2, characterized in that After folding the opening of the inner bag together and before the welding of the inner bag in step d), a portion of the folded portion is removed.

7. The method according to claim 1 or 2, characterized in that The channel has a width of 1 mm to 20 mm.

8. The method according to claim 1 or 2, characterized in that In order to transfer the inner bag into the outer bag in step e), the inner bag is surrounded by a transfer sleeve to maintain the shape of the inner bag.

9. The method according to claim 1 or 2, characterized in that To transfer the inner bag into the outer bag in step e), the opening of the outer bag passes over the lip of a second filling funnel.

10. The method according to claim 1 or 2, characterized in that After transferring the inner bag in step e), the folded portion of the inner bag is turned over.

11. The method according to claim 1 or 2, characterized in that The welding of the outer bag in step f) is carried out similarly to step d).

12. The method according to claim 1 or 2, comprising transferring the outer bag into a transport container as step g).

13. A system for automatic packaging of silicon, the system being configured to perform the method according to any one of claims 1 to 12, the system comprising: - at least one shaped container for the inner bag, - at least one shaped container for the outer bag, - at least one conveying unit for moving the shaped container for the inner bag and the shaped container for the outer bag, - at least one device for opening the opening of the inner bag and / or the opening of the outer bag, - at least one filling unit for filling the inner bag with crushed silicon, - at least one welding unit for welding the inner bag and optionally the outer bag, the at least one welding unit comprising means for folding the opening of the inner bag or the opening of the outer bag inwardly so as to form a fold having a channel; and a vacuum welder placed from the outside on the inner bag or optionally the outer bag, - at least one gripping arm for moving the inner bag, - optionally at least one further welding unit for welding the outer bag.

14. The system of claim 13, comprising a delivery sleeve, the inner bag being surrounded by the delivery sleeve to maintain the shape of the inner bag.

15. System according to claim 13 or 14, comprising cutting means for partially removing the fold.

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