RU2775326C1 - Method and apparatus for manufacturing a storage bag and storage bag - Google Patents

Abstract

FIELD: storage.

SUBSTANCE: disclosed in the invention is a method for manufacturing a storage bag with a built-in valve, the resulting bag, and an apparatus for manufacturing such a bag. Method of manufacturing a storage bag (2) with a first open end (7) and a second open end (8), made with a valve (3), including the following stages. The stage of providing a tubular part (5) made from a web, in particular, of a polymer material, preferably woven polyolefin or woven polypropylene material, followed by closing the first open end (7) of the tubular part (5), preferably by attaching a first insulating tape (10). The stage of forming a valve (3) of the bag (2) by bending the corner (13) of the second open end (8) of the tubular part (5) into the tubular part (5). The stage of cutting the lower edge strip (22) of the tubular part (5) with the formed valve (3) at the second open end (8) of the tubular part. The stage of closing the second open end (8) by attaching a second insulating tape (25) thereto.

EFFECT: integrity and durability of the bag, as well as security of attachment of the valve.

26 cl, 7 dwg

Description

Field of invention

The present invention relates generally to the field of bags for the transport, packaging and storage of powdered or bulk material such as cement.

In particular, the invention relates to a method for manufacturing a bag with an integrated valve, the resulting bag and a device for making such a bag.

Prior Art

Bags or sacks are used to pack/storage/transport materials such as grain, flour and various types of industrial materials. Two types of bags are mainly used: pillow type and box type. Box-type bags are produced by hot sealing, but their production is expensive. Most commonly, pillow bags are made by sewing together one end of a tubular web by suitably folding the end to be sewn. Stitching is a simple and economical process that can be done manually or automatically. However, this compromises the integrity and strength of the web due to needle piercing of the web. Some manufacturers use high-strength material to compensate for the loss of strength, but it is not possible to achieve complete isolation of the retained materials from the external environment. Cross-linking also leads to material theft, especially during transport and bag handling. Also, the fold required for stitching requires a longer web, which is an economic disadvantage.

The problem of web piercing and the theft associated with it can be overcome with thermal sealing techniques such as hot patch welding or ultrasonic methods, however these methods require precise operational control as well as a higher strength web without which there is a risk of rupture of the filled bags, which reduces the weight limit of the package.

Another problem exists with bags that have a filling valve that is designed to fill material more reliably than filling through the open ends of the bag. However, filling valves are usually not securely attached to the bag. Therefore, there is a risk that the valves may open or detach from the bags.

It is known in the art, for example from AT 512459 A1, to provide bags with self-closing valves that allow quick filling and automatic closing of filled bags. The valve is formed in the flattened state of the bag by means of a folding device. The bags are usually filled using a filling device such as a filling tube. To do this, the valve opens and a filling device is inserted into it. After the filling device is removed from the bag, the valve is closed by the internal pressure of the powdered or granular material loaded into the bag. In this prior art, the open end of the valve bag is closed by folding the top edge and then sewing. However, this weakens the web and may cause the bag to break. In addition, the filling material may seep through the stitches, which is especially important when bags are filled with cement.

Accordingly, it is an object of the present invention to eliminate or at least reduce at least some of the disadvantages of the prior art.

Therefore, there is a need for a bag/cool and a method for their manufacture that overcomes these shortcomings so that the integrity and strength of the web is not unduly compromised, and in which the connections are strong and solid and the flaps present are securely fastened.

In particular, it is an object of the present invention to provide a bag with an integrally molded valve that securely closes the filled bag when the filling device is withdrawn from the valve, prevents leakage of the filling material, and is substantially durable. In addition, the aim of the invention is to develop a method and apparatus for the manufacture of such a bag.

Brief summary of the invention

The invention provides a method for manufacturing a bag with a valve. The bag may be made from a linen material, which may be a woven fabric, a nonwoven fabric, or a combination thereof, optionally coated or laminated. Woven polyolefin or woven polypropylene is the preferred material. For the purposes of this description, the terms "web", "linen material" or "fabric" are used interchangeably.

Accordingly, the method includes the following steps:

a) providing a tubular piece made from a web, in particular a polymeric material, preferably a woven polyolefin or woven polypropylene material, having a first open end and a second open end, each open end having a corresponding circular edge;

b) closing the first open end of the tubular part, preferably by attaching a first insulating tape;

c) forming a bag flap by bending the corner of the second open end of the tubular part into the inside of the tubular part;

d) cutting off the lower edge strip of the tubular part with the flap formed at the second open end of the tubular part; and

e) closing the second open end by attaching a second insulating tape thereto.

A linen bag with a valve is also proposed. The bag can be made of linen material, which can be woven fabric, non-woven fabric, coated or laminated. The insulating tapes can be made from woven or non-woven materials, in particular from a polymeric material, preferably woven polyolefin or woven polypropylene, preferably coated or laminated, it is possible to make insulating tapes with an adhesive pre-applied on their surface for attaching to the bag. This means that the tapes used contain a ready-to-use adhesive.

Accordingly, the bag according to the invention contains:

- a tubular part made of a web, in particular of a polymeric material, preferably a woven polyolefin or a woven polypropylene material, the tubular part having a first end closed, preferably by means of a first insulating tape;

- a valve formed by an angle at the second end of the tubular part, bent inside the tubular part, while the height of the valve is less than the depth of the valve; and

- a second insulating tape attached to the second end of the tubular part.

In another aspect, the invention provides a device for making a bag with at least a valve. The device is capable of producing bags made from web, which can be woven, non-woven, coated or laminated.

Accordingly, the device proposed here contains:

a) a supply unit for providing a tubular piece made from a web, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material, having a first open end and a second open end, each open end having a corresponding circular edge;

b) a first closing block for closing the first open end of the tubular part, in particular with a first insulating tape;

c) a valve forming unit for forming a bag valve by bending the corner of the second open end into the inside of the tubular piece;

d) a cutting block for trimming the lower edge strip of the second open end;

e) a second closing block for closing the second open end with a second insulating tape.

All aspects of the invention are related to each other, and any embodiment described for one aspect accordingly refers to the other mentioned aspects and embodiments. In particular, the advantages and features mentioned in the context of the method also apply to the device and bag.

Brief description of the drawings

On FIG. 1 shows a device for making a bag with a shut-off valve.

On FIG. 1A and 1B schematically show pleats formed to form a flap.

On FIG. 2 shows a welding machine for joining at least one valve side wall to an adjacent tubular side wall section using a welding process.

On FIG. 3 shows the connection of the side walls of the valve to the adjacent section of the side wall using a single welding machine.

On FIG. 4 shows an alternative device for making a bag with a check valve.

On FIG. 5 shows the perforation block, side view.

Item List

1. Device

2. Bag

3. Valve

4. Roll of canvas/fabric

5. Tubular part

6. Circular side wall

7. First open end, circular edge of the first open end

8. Second open end; 8A - circular edge of the second open end

9A/9B. Flattened Tubular Sections

10. The first insulating tape

11. Tape roll for the first insulating tape

12. Edge of the first open end

13. Angle

14. Triangle

15. First side or first leg

16. Longitudinal axis of the tubular part

17. Second side or second leg

18. Hypotenuse

19. Valve side wall

20. Dividing element

21. Partition plate

22. Bottom hem strip

23. Height

24. Depth

25. Second insulating tape

26. Tape roll of the second insulating tape

27. Edge of the second open end

28. Connecting / insulating device

29. Hole

30. Bolt

31. Support element

101. Tubular supply unit

102. First closing block for the first open end

103. Valve forming unit

104. Cutting block

105. Second closing block for the second open end

106. Welding machine

107. Valve connection unit

108. Perforation block

109. Block cutting insulating tape.

Detailed description of the invention

The present invention provides a method for manufacturing a bag with a valve, comprising the following steps:

a) providing a tubular piece made from a web, in particular a polymeric material, preferably a woven polyolefin or woven polypropylene material, having a first open end and a second open end, each open end having a corresponding circular edge;

b) closing the first open end of the tubular part, preferably by attaching a first insulating tape;

c) forming a bag flap by bending the corner of the second open end of the tubular part into the inside of the tubular part;

d) cutting off the lower edge strip of the tubular part with the flap formed at the second open end of the tubular part; and

e) closing the second open end by attaching a second insulating tape thereto and securing the valve.

The bag can be made of linen material, which can be woven, non-woven, coated or laminated. Woven polyolefin or woven polypropylene is preferred.

By carrying out steps (a) to (e) of the method, preferably, but not necessarily sequentially, a high strength bag is obtained with an integrally molded self-closing valve, the valve reliably closing the filled bag when the filling device is removed from the bag. The valve closes due to the applied pressure of the filling material. Leakage of the filling material, in particular powdered or granular material such as cement, from the lower end of the bag is reliably prevented. The valve is thus formed by the tubular part itself and thus constitutes an integral part of the bag. In other words, the bag including the valve is made in the form of a single piece, namely a tubular piece.

The type of bag produced, such as pillow type or side gusseted, is determined by the shape of the tubular piece used in the manufacturing process. Therefore, depending on the type of bag being produced, the tubular piece may have folds. The claimed method and the claimed device can be used for the manufacture of both types of bags.

The tubular part may be made of a synthetic woven material, in particular a polymeric material, preferably a polyolefin or polypropylene. The web may consist of small ribbons or strips typically up to 10 mm wide and 15 to 120 µm thick. The web may be coated or uncoated. The tubular piece has a circular side wall which preferably has no slots or holes other than the first and second open ends. The side wall may comprise multiple side wall sections. Typically, each sidewall section forms one side of the bag being made. Due to the bendability of the material used, the tubular piece is preferably in a flattened state during the manufacture of the bag. In this state, the side wall can be divided into at least two sections, the upper and lower sections of the side wall, connected to each other at the side edges of the flattened tubular piece. The first open end of the tubular is opposite the second open end of the tubular. At the start of the method in step (a), the first and second open ends of the tubular piece preferably have substantially the same size.

In step (a) of providing the tubular, it is physically located and prepared for subsequent steps. The step of providing the tubular part may comprise manufacturing it. For example, the tubular piece may be woven or cut from a roll (web) or using any other means of supplying continuous tubular pieces, such as a woven web. Alternatively, the manufacture may be independent and carried out before step (a). In this case, the tubular part can simply be taken from a stack of many tubular parts.

In step (b), the first open end of the tubular is closed. Various techniques may be used to close the first open end. For example, the first open end may be closed by sewing or gluing. Preferably, however, the first open end is closed by a first insulating tape which is attached to the edges of opposite side wall sections at the first open end. The first insulating tape may be taken from a stack of insulating tapes or may be cut from a continuous insulating tape. If the first insulating tape is cut from the continuous insulating tape, the cutting may occur before or after the first insulating tape is attached to the first open end. The first insulating tape preferably has two tape blocks, one for each connected to each other section of the side wall of the tubular piece. In particular, the cross section of the first insulating tape has a V or U shape. The first insulating tape can be glued or welded to the tubular part, preferably by means of hot air or thermal welding. As thermal welding, laser, ultrasonic or other high-frequency welding technologies can be used. Two blocks of tape, ie elements of U-shaped or V-shaped cross-section, are thus attached to the edge of the first open end. Alternatively or additionally, the first insulating tape at the first open end may be sewn to the tubular since the stresses on the joint may be less at the first (upper) open end than at the second (lower) open end of the tubular.

The first insulating tape may be made from a woven or non-woven material, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material, preferably coated or laminated, optionally pre-applied with an adhesive.

In step (c), the valve is formed by folding the corner of the second open end, which is still open at this step, into the inside of the tubular. Since the tubular piece is usually in a flattened state due to its ability to transform, it may be useful to lift one edge of the second open end to facilitate corner folding. The resulting valve has two opposite side walls so that a filling device can be placed between them. In step (c), the height and depth of the folded flap are substantially the same. The direction of the height of the valve is parallel to the longitudinal axis of the tubular part extending from the first open end to the second open end. The direction of depth is perpendicular to the longitudinal axis of the tubular part.

In step (d), the lower edge strip of the tubular piece with the flap formed at the second open end is cut off, for example with a knife. This cut is preferably a straight cut without curved sections. As a result of the cut, the valve is truncated at its lower end. Thus, the resulting valve in the final state has a height that is less than its depth. In other words, the height of the flap formed after the corner is folded is reduced by the width of the cut lower edge strip. This improves the reliability of the bag's self-closing valve mechanism by preventing the valve from accidentally turning outwards when the bag is filled with material. The lower edge strip has a width of at least 10 mm, preferably at least 70 mm, preferably less than 150 mm. After cutting off the lower edge strip, the tubular piece has a finite length (ie, extension in the direction of the longitudinal axis) of the bag to be produced.

In step (e), the second open end of the tubular piece, on which the valve is placed, is closed by attaching a second insulating tape thereto. In this case, due to the attachment of the second insulating tape, the valve is not blocked. As in the case of attaching the first insulating tape, the second insulating tape may be taken from a stack of insulating tapes or may be cut from a continuous insulating tape, in particular from a roll. If the second insulating tape is cut from the continuous insulating tape, the cut may occur before or after the second insulating tape is attached to the second open end. The second insulating tape preferably has two blocks of tape, one block for each of the tubular side wall sections to be connected. In particular, the cross section of the second insulating tape has a V or U shape. The second insulating tape may be glued or welded to the tubular piece. Thus, two blocks of tape connected in a U-shaped or V-shaped section are attached to the edge of the second open end. Alternatively or additionally, the second insulating tape at the second open end may be sewn to the tubular piece.

The second insulating tapes can be made from woven or non-woven materials, in particular from a polymeric material, preferably a woven polyolefin or a woven polypropylene material, preferably coated or laminated, with an optional pre-applied adhesive.

As one of the key aspects of the invention, the formed valve is secured so that it does not unfold when the bag is filled or otherwise. The easiest way to achieve this is to securely attach at least one of the valve walls to the second insulating tape. In a preferred method of securing the valve, at least one hole is formed in at least one adjacent side wall section to make a secure connection between the second insulating tape and at least one side wall of the valve in step (e). When the second insulating tape is attached to the second open end in step (e), for example by gluing or welding, preferably hot air welding or heat welding, at least one side wall of the valve is connected to the second insulating tape through at least one hole. The second insulating tape may be glued or welded, preferably by means of hot air or thermal welding, to the tubular piece. As thermal welding, laser, ultrasonic or other high-frequency welding technologies can be used. Since the second insulating tape is also connected to the adjacent side wall of the tubular piece, the second insulating tape will connect at least one side wall of the valve to the adjacent side wall section. At least one hole is preferably located so close to the second open end that it can be completely covered by the second insulating tape.

Preferably, the first and/or second insulating tapes are attached to the tubular part by welding, preferably hot air welding or ultrasonic welding, or gluing.

The position of at least one opening may be predetermined depending on the size of the bag and valve. As a result, the formation of at least one hole can be performed at almost any time during the implementation of the method (i.e., including before steps (b), (c), (d) and (e)) if the positions of the cuts are known, which must be done to obtain tubular parts 5 from a tubular web.

After step (e) is completed, the excess portion of the second insulating tape is cut off to fit the width of the second open end (closed at this point) of the bag, taking into account the valve. As a result, the second insulating tape does not protrude into the valve area.

As shown in FIG. 1A and 1B, in a preferred embodiment, the inwardly folded corner of the second open end to form the flap is in the form of a triangle, in particular an isosceles triangle. In this embodiment, the first side (first leg) of the triangle is oriented essentially in a direction perpendicular to the longitudinal axis of the tubular part, and the second side (second leg) is oriented essentially in a direction parallel to the longitudinal axis of the tubular part. As shown in FIG. 1A, before the fold was formed by folding the side walls, the first side of the triangle was part of the folded side edge of the flattened tubular piece. Likewise, prior to the formation of the fold, the second side was part of the open edge of the second open end. The hypotenuse connects the side wall to the second open end.

In accordance with one embodiment of the invention, step (d) may include cutting off the bottom edge strip substantially at right angles to the longitudinal axis of the tubular and across the entire width of the second open end of the flap-shaped tubular. The longitudinal axis thus extends from the first open end to the second open end of the tubular.

As an alternative method of securing the flap so that it does not unintentionally open or turn inside out (precisely in the opposite direction of the previously described inward folding), after the formation of the flap in accordance with step (c), at least one side wall of the flap, preferably the lower edge of the side valve wall, securely connected to the adjacent section of the side wall of the tubular part. Preferably, both sidewalls of the valve are connected to a respective adjacent sidewall section of the tubular.

A quick and secure connection of the valve sidewalls can be achieved if at least one valve sidewall is bonded to an adjacent tubular sidewall section using a hot melt bonding process. Alternatively, any welding process can be used for this purpose where the web can be partially melted and at least one flap sidewall can be joined to an adjacent tubular sidewall section without the use of any joining materials such as adhesive. Again, it is preferred that both valve sidewalls are connected to respective adjacent tubular sidewall sections. To this end, both side walls of the valve can be connected to the corresponding adjacent side section of the tubular part at the same time. Alternatively, the sidewalls of the valve may be connected to their adjacent tubular sidewall sections one after the other, ie in separate welding processes.

During the welding process, in order to avoid joining the side walls of the valve to each other, a separating element, in particular a separating plate, preferably made of steel, can be used to temporarily separate the side walls of the valve from each other during the welding process. The separating element has the advantage that the side walls of the valves are not welded to each other during the welding process.

Alternatively, welding may be performed using an ultrasonic welding process.

In a further embodiment, two valve mounting methods are used, namely

- the first method, providing for the implementation of at least one hole in at least one section of the side wall, through which (which) the second insulating tape is securely connected to one side wall of the valve,

- and another method in which at least one side wall of the valve, preferably the lower edge of the side wall of the valve, is securely connected to an adjacent section of the side wall of the tubular piece.

In addition, the present invention provides a linen bag containing

- a tubular part made, in particular, of a woven material, and the tubular part has a closed first end, preferably by means of a first insulating tape;

- a valve formed by an angle at the second end of the tubular part, bent inside the tubular part, and the height of the valve is less than the depth of the valve;

- a second insulating gasket attached to the second end of the tubular part.

The bag can be obtained by the claimed method. Advantageously, the bag flap has a height less than its depth. The height of the valve increases in a direction parallel to the longitudinal axis of the tubular piece, which extends from the first open end to the second open end. The depth is directed perpendicular to the longitudinal axis of the tubular part. The longitudinal axis extends from the first open end to the second open end. The bag has a length preferably from 200 mm to 1400 mm, more preferably from 350 mm to 950 mm. The bag has a width preferably from 170 to 850 mm, more preferably from 270 to 620 mm.

To prevent inadvertent inversion of the bag flap, at least one of the side walls of the flap may be connected to an adjacent side wall section of the tubular.

The invention also provides a device for making a bag with at least one valve, comprising:

a) a supply unit for providing a tubular piece made from a web, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material, having a first open end and a second open end, each open end having a corresponding circular edge;

b) a first closing block for closing the first open end of the tubular part, in particular with a first insulating tape;

c) a valve forming unit for forming a bag valve by bending the corner of the second open end into the inside of the tubular piece;

d) a cutting block for trimming the lower edge strip of the second open end;

e) a second closure block for closing the second open end with a second insulating tape.

The device of the present invention makes it possible to implement the method described above. Preferably, the blocks are arranged sequentially from (a) to (e). The supply unit may comprise a roll of wound continuous tubular parts from which the tubular part can be cut, for example by cold cutting, hot cutting, ultrasonic cutting or laser cutting. Alternatively, the supply unit may comprise a stack from which the tubular parts can be removed one after the other. The first closing block may comprise a set of insulating tapes, in particular V-shaped or U-shaped tapes. The insulating tape can be taken from a stack of insulating tapes or can be cut from a roll. For cutting, the first closing block may contain a knife. Alternatively, cold, hot, ultrasonic or laser cutting may be used in the first closure block. The valve forming unit may include a folding element that folds, that is, compresses or shifts the angle of the tubular part into the inside of the tubular part. Desirably, the valve forming unit may further comprise a lifting element which raises the edge of the second open end of the tubular to allow the corner to fold. The cutting block may include a knife. The second closing block can be constructed similarly to the first closing block. In the first and/or second closure unit, welding, preferably hot air welding, ultrasonic welding or gluing, may be used to attach the first and/or second insulating tape to the tubular piece.

In a first embodiment of the device, the first and/or second closure unit has a welding device for connecting the first/second insulating tape to the first/second open end of the tubular. The welding device, preferably a heat sealing device, can heat and partially melt the first/second insulating tape and/or the first/second open end to form a continuous connection between the first/second insulating tape and the tubular. The welding device may also be an ultrasonic welding device.

In addition, the device may include an adhesive block connecting at least one side wall of the valve to an adjacent section of the side wall of the tubular piece with an adhesive.

In a preferred embodiment of the invention, the device further comprises a punching unit for punching at least one hole in at least one section of the side wall of the tubular before closing the second open end with the second insulating tape, while the hole (s) is punched close to the edge of the second open end, so that when the second insulating tape is attached, the connection of the second insulating tape and at least one side wall of the valve is made.

The position of at least one opening may be predetermined depending on the size of the bag and valve. As a result, the formation of at least one hole can be performed at almost any time during the implementation of the method (i.e., including before steps (b), (c), (d) and (e)) if the positions of the cuts are known, which must be done to obtain tubular parts 5 from a tubular web.

In another embodiment of the invention, the device comprises a welding machine for connecting at least one sidewall of the valve to an adjacent sidewall section of the tubular piece using a welding process, preferably a heat sealing process. Also, the process may also be an ultrasonic welding process.

In order to avoid joining the side walls of the valve during the welding process, the welding machine may comprise a separating element, in particular a separating plate, preferably made of steel, which can be inserted between the side walls of the valve during the welding process.

In yet another embodiment of the invention, the device comprises both the aforementioned perforating unit for the purpose of the preferred embodiment and a welding rig for connecting at least one valve side wall to an adjacent tubular side wall section using a welding process.

Further preferred embodiments of the invention are described with reference to the drawings.

On FIG. 1 schematically shows the device 1, namely the production line for the production of bags 2 with an integrated valve 3. The production line has a number of processing units for the production of bags (from left to right). The sequence shown in Fig. 1 is only one preferred embodiment, however the individual steps may be substituted or combined as long as the result remains substantially the same. Each step performed can be performed by a dedicated unit of the apparatus 1. Since such units are known per se, they are only shown schematically in the drawings.

On FIG. 1 also shows a web roll 4 from which tubular parts 5 have been cut with a cutting block such as a knife or a laser cutter (not shown). Each tubular piece 5 typically has a circular sidewall 6 that extends in the direction of the longitudinal axis of the tubular piece, preferably without slots or openings other than a first open end 7 and a second open end 8 at opposite ends of the tubular piece 5. Each open end 7 and 8 has a corresponding peripheral circular edge. The tubular parts 5 are made of a linen material, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material. Due to the ability to transform tubular parts 5 in the production process are in a flattened state, as shown in the drawings. In this flattened state, at least two opposite side wall sections 9A and 9B of the tubular piece 5 are formed by side edges 6A and 6B. On FIG. 1, only the upper part 9A of the side wall can be seen, since the tubular piece 5 is shown in plan view.

Alternatively, instead of cutting, the tubulars 5 may, of course, simply be taken from a stack or other production line to produce the tubulars 5. The step of cutting or simply removing the tubulars 5 may be collectively referred to as the tubular providing step, or simply step (a). This step is performed by the supply unit 101 .

In the next step, which may be referred to as step (b) and is performed by the first closing block 102, the first open ends 7 of the tubulars 5 are completely closed so that the material subsequently filling the bag 2 does not exit from that side of the bag 2. Preferably, this is done by attaching the first insulating tape 10 to the first open end 7. To do this, the first insulating tape 10 can be cut from the tape roll 11 or, alternatively, removed from the stack. The length of the first insulating tape 10 may be greater than the width of the first open end 7. There are various ways of attaching or connecting the first insulating tape 10 to the first open end 7. However, welding or gluing is preferred. For this purpose, a connecting or insulating device 28 is used, in particular a device that connects using glues/adhesives (natural or synthetic), or a device that uses welding technologies such as laser welding, ultrasonic welding or any other high frequency welding or device. for hot air welding. Such a connecting device 28 may be included in the first closing block 102.

The first insulating tape 10 preferably has two blocks (not shown) of tape, one for each sidewall section 9A (upper side) and 9B (lower side) connected to each other of the tubular part 5. In particular, the cross section of the first insulating tape 10 forms V or U shape. Two blocks of the first insulating tape 10, i.e. branches of U-shaped or V-shaped cross-section, are thus attached to the edge 12 of the first open end 7. Alternatively or additionally, the first insulating tape 10 at the first open end 7 may be sewn to the tubular part 5, since at the first (upper) open end 7 the load on the junction may be less than at the second (lower) open end 8.

Then, in step (c) carried out by a block called a valve forming block 103, a valve 3 is formed in the tubular part 5. To do this, the corner 13 at the second open end 8 is folded into the inside of the tubular part 5. As seen in FIG. 1, when the corner 13 is bent inward, two isosceles triangles 14 are formed, which have a common side or edge, the common side being the first side 15 (the first leg). Thus, the first side 15 of the triangles 14 is formed by what was part of the side edge 6A and is oriented essentially in a direction perpendicular to the longitudinal axis 16 of the tubular piece 5. Similarly, when folded inward, the second side (second leg) 17 of each triangle 14 is formed from what was part of the circular edge 8A. The second side 17 of each triangle 14 is oriented substantially in a direction parallel to the longitudinal axis 16 of the tubular piece 5. Finally, the hypotenuses 18 of the triangles 14 are formed by the fold of the side walls 9A and 9B.

Obviously, the unity of the valve 3, which is eventually formed together with the rest of the bag, is ensured by the fact that:

- the first side 15 of the triangles 14 is an integral part of the folded side edge 6A;

the second sides 17 of the triangles 14 are integral to the peripheral edge 8A; and

the hypotenuses 18 are part of the side walls 9A and 9B.

Although the flap 3 is integral with the bag in the manner described here, to prevent the flap from inadvertently turning outward (precisely in the opposite direction of the previously described folding inward), the device according to the present invention is provided with a perforation block 108.

After cutting the tubular part 5 from the web roll 4, at least one hole 29 is formed in at least one of the adjacent sidewall sections 9A and 9B by means of a perforation block 108 (see Fig. 3) in order to establish a connection in step (e) between the second insulating tape 25 and at least one of the side walls 19 of the valve. In the embodiment shown, two holes 29 are punched. Both holes 29 may be in the same wall section 9A or wall section 9B, or they may be in different wall sections 9A and 9B. The holes 29 may be arranged in any configuration relative to each other, provided that the second insulating tape 25, when placed in its final position, covers at least one of the holes 29. The punching of the holes 29 must occur before or at the beginning of step (e) . Thus, the perforation block 108 can be placed anywhere in the device 1, provided that the holes 29 are punched before or at the beginning of step (e). The holes 29 may be through holes that pass through the side wall sections 9A and 9B of the tubular 5 and both side walls 19 of the valve 3. Alternatively, it is sufficient that the holes 29 pass through only one of the respective adjacent sections 9A and 9B of the tubular 5 The second insulating tape 25 is finally attached to the second open end 8 in step (e) using a second welding device 28, which may be part of the second closing block 105. Welding or bonding is preferred, but ultrasonic welding can also be used.

Due to the attachment of the second insulating tape 25 to the second open end 8, the side wall 19 of the valve 3 is connected to the second insulating tape 25 through the holes 29. 5, the side wall 19 of the valve 3 is connected to the adjacent side wall section 9A or 9B by a second insulating tape 25. The holes 29 are located so close to the second open end 8 that they are completely covered by the second insulating tape 25.

On FIG. 5 shows the perforation block 108 in side view. The perforating block 108 includes a sliding bolt 30 which punches at least one hole 29, preferably two holes 29, in the sidewall sections 9 and the sidewalls 19 of the valve 3. The support member 31 supports the tubular piece 5 and receives the bolt 30.

The position of the holes 29 can be predetermined depending on the size of the bag and valve. As a result, the formation of holes 29 can also be performed at almost any time during the implementation of the method (i.e., including before steps (b), (c), (d) and (e)) if the positions of the cuts to be made are known. to obtain tubular parts 5 from a tubular web.

As an alternative to securing the valve via holes 29, at least one of the side walls 19 of the valve 3, preferably the edge proximate the second open end 8, is securely connected to the respective adjacent side wall section 9A or 9B of the tubular 5. This step may be performed in a block that may be collectively referred to as a valve connection assembly 107 (see FIG. 4). Preferably, each of the side walls 19 of the valve 3 is connected to a respective adjacent side wall section 9A or 9B of the tubular 5. 5).

Fast and reliable connection of the side walls 19 of the valve 3 can be achieved if the side walls 19 of the valve 3 are connected to the respective adjacent side wall portions 9A and 9B of the tubular 5 by a welding process, in particular an ultrasonic welding process performed by the welding machine 106. This is more shown in detail in Fig. 2. During the welding process, the web of the tubular 5 and the flap 3 formed therein is partially melted, and the walls 19 of the flap 3 are connected to the respective adjacent side wall sections 9A and 9B of the tubular 5 without the use of any adhesive material such as glue.

As already described, it is preferable that both side walls 19 of the valve 3 are connected to the corresponding adjacent side wall section 9A or 9B of the tubular piece 5. For this purpose, separate welding processes can be used, performed by separate welding stations 106. The welding stations 106 can be activated simultaneously or sequentially. As shown in FIG. 4 welding stations 106 can be integrated into the valve connection assembly 107 .

In order to avoid joining the side walls 19 of the valves 3 to each other, a separating element 20, in particular a separating plate 21, preferably made of steel, can be used during the welding process to temporarily separate the side walls 19 of the valve 3 from each other. The separating element 20 prevents the side walls 19 of the flaps 3 from being unintentionally welded to each other during the welding process.

Instead of welding, the side walls 19 of the valve 3 may be connected to respective adjacent side wall sections 9A or 9B of the tubular parts 5 with an adhesive material, which may be a natural or synthetic adhesive, preferably a hot melt adhesive. This step can be carried out using a gluing block that can be integrated into the valve connection assembly 107 .

In yet another embodiment, the apparatus comprises both the aforementioned perforation block 108 for the purpose for which it was provided in the preferred embodiment, and a welding rig 106 for joining at least one valve sidewall to an adjacent tubular sidewall section using a process welding.

In step (d), which can be performed by a cutting block 104 following the valve forming block 103 or the valve connection 107, the lower edge strip 22 of the tubular piece 4 with the valve 3 at the second open end 8 is cut off, for example, with a knife or other cutting device (not shown). The cut is preferably a straight cut without curved sections. As a result, the valve 3 obtained in its final state has a height 23 that is less than its depth 24. In other words, the height 23 of the valve 3 is reduced by the width of the cut lower edge strip 22. The height 23 of the valve 3 increases in a direction parallel to the longitudinal axis 16 of the tubular part 5, which extends from the first open end 7 to the second open end 8. The depth 24 is directed perpendicular to the longitudinal axis 16 of the tubular part 5. This increases the reliability of the self-closing mechanism of the valve 3 of the bag 2, since the valve 3 is prevented from accidentally turning outward when the bag is filled with material. The cutting of the lower edge strip 22 can be carried out essentially at right angles to the longitudinal axis 16 of the tubular part 5 and across the entire width of the second open end 8 of the tubular part with the flap 3 formed.

After cutting off the lower edge strip 22, the second open end 8 is closed by attaching a second insulating tape 25 thereto in a step that may be referred to as step (e). This step may be performed by a second closure device 105, which may be similar to the first closure device 102. In this respect, "closing" means closing the second open end 8 after removing the lower edge strip 22, but leaving the flap 3 open. In other words, the open end 8 is closed, but the valve 3 is still open to receive material. As already noted, the second insulating tape 25 can be taken from a stack or, as shown, cut from a continuous tape roll 26. Similar to the first insulating tape 10, the second insulating tape 25 preferably has two tape sections, one for each side wall 9A and 9B tubular parts 5 connected to each other. Specifically, the cross section of the second insulating tape 25 is V or U shaped. Two blocks of tape connected in a U or V shape are attached to the edge of the second open end. Alternatively or additionally, the second insulating tape 25 at the second open end 8 may be sewn to the tubular 5. The second insulating tape 25 may be glued or preferably welded to the tubular 5. For this purpose, another connecting or insulating device 28 may be included in the second closing block 105.

Since the second insulating tape 25 may be too long and protrude from the bag 2 due to the valve 3, a tape cutting unit 109 may be placed at the end of the device 1. This cutting unit 109 cuts off the part of the second insulating tape 25 protruding above the valve 3.

The above process carried out by the device 1 results in a bag 2 with a closed first end (corresponding to the first open end 7) and a second end 8 with a valve 3 made on it. The second end 33 corresponds to the second open end 8 closed by the second insulating tape 25.

Preferably, the modules 101, 102, 103, 104 and 105 shown in the drawings are placed on the production line in the order 101, 102, 103, 104 and 105.

The advantages of bags made using the method and apparatus described here are obvious.

Although the above description contains many specific features, they should not be construed as limiting the scope of the invention, but rather as illustrating preferred embodiments. It should be understood that modifications and changes based on the above description are possible without deviating from the essence and scope of the invention. Accordingly, the scope of the invention is to be determined not by the embodiments given, but by the appended claims and their legal equivalents.

Claims (39)

1. A method for manufacturing a bag (2) for storage, having a first open end (7) and a second open end (8) and made with a valve (3), comprising the step of providing a tubular part (5) from a web, in particular a polymeric material, preferably woven polyolefin or woven polypropylene material, followed by closing the first open end (7) of the tubular part (5), preferably by attaching the first insulating tape (10), characterized in that it contains subsequent steps a. forming the valve (3) of the bag (2) by bending the corner (13) of the second open end (8) of the tubular part (5) inside the tubular part (5), b. cutting off the lower edge strip (22) of the tubular part (5) with a valve (3) formed at the second open end (8) of the tubular part and c. closing the second open end (8) by attaching a second insulating tape (25) to it. 2. The method according to claim 1, wherein the inwardly folded corner (13) of the second open end (8) to form the valve (3) is made in the form of a triangle (14). 3. The method according to claim. 1 or 2, characterized in that in step (b) cutting off the lower edge strip (22) is carried out essentially at right angles to the longitudinal axis (16) of the tubular part (5) and across the entire width of the second open end (8) tubular piece (5) with formed valve (3). 4. The method according to paragraphs. 1, 2, characterized in that before step (c) at least one hole (29) is formed in at least one of the adjacent sections (9A or 9B) of the side wall in order to establish a connection between the second insulating tape in step (c) (25) and at least one of the side walls (19) of the valve (3). 5. The method according to paragraphs. 1, 2, characterized in that after the formation of the valve (3) in accordance with step (a), at least one side wall (19) of the valve (3), preferably the lower edge of the side wall (19) of the valve (3), is connected to adjacent section of the side wall (9A or 9B) of the tubular part (5). 6. The method according to claim 5, characterized in that at least one side wall (19) of the valve (3) is connected to the corresponding adjacent side wall section (9A or 9B) of the tubular part (5) by welding, in particular ultrasonic welding. 7. The method according to claim 6, characterized in that during the welding process, a separating element (20), in particular a separating plate (21), preferably made of metal, is used to temporarily separate the side walls (19) of the valve (3) from each other. . 8. The method according to claim 5, characterized in that at least one side wall (19) of the valve (3) is connected to the corresponding adjacent section (9A or 9B) of the side wall of the tubular part (5) using an adhesive material, preferably hot melt adhesive. 9. The method according to paragraphs. 1, 2, characterized in that the first and/or second insulating tapes (10, 25) are attached to the tubular part (5) by welding, preferably by hot air welding or ultrasonic welding, or by gluing using an adhesive. 10. Method according to claim 5, characterized in that at least two holes (29) are arranged in any relative configuration with respect to each other. 11. Method according to claim 10, characterized in that after closing said second open end (8), said second insulating tape closes at least one said opening (29). 12. The method according to paragraphs. 1, 2, characterized in that the cross section of the first and second insulating tape is V-shaped or U-shaped. 13. The method according to paragraphs. 1, 2, characterized in that the first insulating tapes (10) and/or the second insulating tapes (25) are made of a woven or non-woven material, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material, preferably with a coating or lamination. 14. The method according to paragraphs. 1, 2, characterized in that the first insulating tape and the second insulating tape are used with glue previously applied to the side that is attached to the bag. 15. Bag (2) for storage, made of linen material, characterized in that said bag contains - a tubular piece (5) made of a web, in particular a polymeric material, preferably a woven polyolefin or a woven polypropylene material, the tubular piece (5) having a first end (32) closed, preferably by means of a first insulating tape (10); - valve (3) formed by an angle (13) at the second end (8) of the tubular part (5), bent inside the tubular part (5), while the height (23) of the valve (3) is less than the depth (24) of the valve ( 3); - a second insulating tape (25) attached to the second end (8) of the tubular part (5); moreover, the first insulating tape (10) and/or the second insulating tape (25) is made of woven or non-woven polymeric material and is made with adhesive pre-applied to the side that is attached to the bag, and sections (9A and 9B) of the side wall of the tubular part have at least one hole (29), which is closed by said second insulating tape (25). 16. Bag according to claim 15, characterized in that at least one of the side walls (19) of the valve (3) is connected to an adjacent section (9) of the side wall of the tubular part (5). 17. Bag according to claim 15, characterized in that at least two holes (29) are located in any relative configuration with respect to each other. 18. Bag according to claim 15, characterized in that the first insulating tapes (10) and/or the second insulating tapes (25) are made of woven polyolefin or woven polypropylene material, preferably coated or laminated. 19. Device (1) for making a bag (2) for storage with at least one valve (3), characterized in that said device contains a) a supply unit (101) for providing a tubular part (5) made from a web, in particular from a polymeric material, preferably a woven polyolefin or a woven polypropylene material, having a first open end (7) and a second open end (8); b) a first closing block (102) for closing the first open end (7) of the tubular part (5), in particular with a first insulating tape (10); c) a valve forming unit (103) for forming a valve (3) of the bag (2) by bending the corner (13) of the second open end (8) inside the tubular part (5); d) cutting block (104) for trimming the edge strip (22) of the second open end (8); e) a second closing block (105) for closing the second open end (8) with a second insulating tape (25). 20. The device (1) according to claim 19, characterized in that it further comprises a perforating block (108) for punching at least one hole (29) in at least one section (9A and/or 9B) of the side wall of the tubular part ( 5) before closing the second open end (8) with the second closing block (105), while the holes (29) are located so that when the second insulating tape (25) is attached, a connection is made between the second insulating tape (25) and at least one side wall of the valve (9). 21. Device according to claim 20, characterized in that said perforation block is located in front of said second closing block (105). 22. Device (1) according to paragraphs. 19-21, characterized in that the first closing block (102) and/or the second closing block (105) contains an adhesive device or welding device for attaching the first/second insulating tape (10, 25) to the first/second open end (7, 8) a tubular piece (5), wherein the welding device is preferably capable of hot air welding or ultrasonic welding. 23. Device (1) according to paragraphs. 19-21, characterized in that it additionally contains a gluing block connecting at least one side wall (19) of the valve (3) with an adjacent side wall section (9A or 9B) of the tubular part (5) using glue. 24. Device (1) according to paragraphs. 19-21, characterized in that it further comprises a welding installation (106) for connecting at least one side wall (19) of the valve (3) with an adjacent section of the side wall (9A or 9B) of the tubular part (5) by means of a welding process, preferably ultrasonic welding process. 25. The device (1) according to claim. 24, characterized in that the welding installation (106) contains a separating element (20), in particular a separating plate (21), which can be inserted between the side walls (9) of the valve (3) in time of the welding process. 26. Device according to claim 20, characterized in that said perforating block (108) comprises a sliding bolt (30) for punching a hole (29) and a support element (31), which is provided under said tubular piece (5) when punching a hole ( 29).

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