Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
  • B65D31/08—Bags or like containers made of paper and having structural provision for thickness of contents with block bottoms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
  • B65D31/14—Valve bags, i.e. with valves for filling

Definitions

• a valve bag and method of manufacturing are provided.
• the invention relates valve bags made of paper, and particularly to the making of the valve bottom.
• the invention relates to multilayer valve bags, where a barrier film is arranged in between the paper layers. In that case air can be exhausted from the bag during the filling process, so that air is conducted in between the barrier layer and the inner layer to the area of the bag bottoms, and further out thereof.
• Paper bags are manufactured by forming a paper web into a flattened tube, which is cut into blanks. At one end of the blank, there can be made a flat bottom by gluing, so that at the blank edges, triangular end flaps are folded inwards, and side flaps are folded on top of these. Generally a bottom patch is glued on top of this.
• valve bags both ends of the bag are closed, but at one end, there is made a filling valve by leaving the interval between the end flap and the side flaps unglued.
• At the valve end there can additionally be attached, at a length from the edge of the end flap, a valve extension that improves the air-tightness of the bag.
• multilayer bags can be manufactured.
• Moisture-proof bags can be manufactured by placing a separate plastic barrier film between the paper layers.
• a separate plastic barrier film Particularly polyethylene has been used as the plastic material.
• a problem with this type of valve bags has been that air is not exhausted from the bag during the filling process. Therefore the barrier film has been perforated, which of course essentially weakens its sealing properties.
• the exhaustion of air from a valve bag can also be arranged so that air is conducted in between the barrier film and the inner layer to the bag bottom area and further out via the bottom ends.
• This kind of bag is introduced in the Finnish patent publication FI-A-945831.
• FI-A-972664 there is described a similar bag, where the layer ends are laminated in order to improve the air-tightness.
• air proceeds on one side of the bag only to one end, and on the opposite side of the bag only to the opposite end. At the valve end. air is exhausted only at the end opposite to the valve, when the filling valve is set tightly in place.
• the present invention relates to a bag according to claim 1 , and to the manufacturing method and use of said bag. Preferred embodiments of the invention are described in the dependent claims.
• valve bottom is provided with an inner bottom patch placed under the side flaps and extending from one end flap to the other.
• the inner bottom patch makes the structure stronger and tighter as well as more solid.
• An inner bottom patch is particularly advantageous in multilayer bags, where air is allowed to be exhausted from between the layers in the bag bottom area.
• air can also be exhausted at the valve bottom, via both ends of the bottom, so that air is exhausted in a very efficient way.
• air can be conducted to the bottom at both ends of the bottom, too, which further improves air exhaustion.
• Figure 1 illustrates a blank where the end flaps are folded.
• Figure 2 illustrates a blank to which an inner bottom patch is attached.
• Figure 3 illustrates a blank provided with the necessary gluings required by the sealinog of the bottom.
• Fi 'g6ure 4 illustrates how the bottom is sealed.
• Figure 5 illustrates how the bottom patch is attached to the bottom.
• Figure 6 illustrates a ready-made bag.
• the bag according to the drawings is manufactured of a three-layered material. Innermost there is an inner layer 1 made of paper, further out a barrier layer 2 impermeable to air, and outermost an outer layer 3 made of paper.
• the inner layer 1 and the outer layer 3 can be made of a suitable bag paper (strength for example 95 give/ ) .
• the barrier layer 2 can be made of a suitable plastic film (for example. HDPE).
• the inner layer 1 extends somewhat further than the barrier layer 2 and the outer layer 3.
• the blank layers are attached together by means of a transversal point-by-point gluing.
• This improves the strength and also makes it easier to align the layers in the manufacturing process.
• air can, however, flow out in between the inner layer 1 and the barrier layer 2.
• the best way to realize the gluing is to provide the barrier layer at the glue points with holes 4, through which the paper layers are glued together.
• an ordinary paper glue that is easy to handle (for instance a starch glue).
• the holes in the plastic barrier layer can be made conveniently by melting with a hot pin.
• a rectangular inner bottom patch 7 which extends from the end flap 5 to the valve end flap 5'.
• the corners of the inner bottom patch extend somewhat over and outside the edges of the end flaps.
• the inner bottom patch is glued to the inner layer 1 of the end flap 5 by a uniform glue strip 8, and to the outer layer 3 by a uniform glue strip 9.
• the inner bottom patch is glued at the edges to the end flaps and to the inner surface of the inner layer by uniform glue strips 10 extending from the end flap 5 to the valve end flap 5'.
• the glue strip 8 extends over the side folding line to the glue strips 10.
• the ends of the glue strip 9 are left inside the side foldin *og lines.
• the gap between the valve end flap 5 ' and the inner bottom patch 7 is left open and forms a filling valve.
• the glue strip 14 extends from the inner bottom patch 7, from the side folding line 11, to the edge of the side flap 12.
• the inner layer of the side flap that falls underneath is glued to the inner bottom patch.
• the inner edge of the side flap that falls on top is glued to the inner bottom patch, but its outer edge is glued to the inner layer of the side flap that is placed underneath.
• the edge of the topmost side flap is left at spaced apart from the edge of the barrier layer 2 of the lower side flap and of the edge of the outer layer 3.
• a bottom patch 15 (Fig. 5) can be glued to the bottom.
• the bottom patch is made of paper, it is of the same size as the bottom and rectangular in shape.
• the other end of the bag blank can be closed in similar fashion, but so that both ends are sealed by gluing.
• one of the ends can be closed according to the method described in the publications FI-A-945481 and FI-A-972664.
• the bag (Fig. 6) is filled through the valve by means of a pipe, which is pushed in an air-tight fashion between the valve end flap 5' and the inner bottom patches 7.
• air is exhausted therefrom through the inner layer 1 to between the inner layer and the barrier layer 2. There it flows to the bag bottoms and is exhausted at both ends via both side flaps.
• an inner bottom patch is provided at the bottom, air is exhausted on top of it, and to below a possible bottom patch 15. Because the bottom patch is glued by uniform sealings at the edges, air is exhausted from underneath the bottom patch at the bottom ends. Owing to the inner bottom patch, air can also be exhausted from the valve bottom at both ends thereof.
• the inner bottom patch also makes the bottom structure more air-tight.
• either the inner layer or the outer layer 3 can be provided with longitudinal grooves.
• the inner layer 1 can be suitably perforated.
• air is exhausted very efficiently, which reduces disturbances at the filling machine. Respectively, filling speeds can be further increased.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bag Frames (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8557227

Family Applications (1)

Country Status (3)

Citations (4)

• 2000
  • 2000-01-28 FI FI20000169A patent/FI20000169A/sv unknown
• 2001
  • 2001-01-26 WO PCT/FI2001/000071 patent/WO2001054995A1/en active Application Filing
  • 2001-01-26 AU AU2001231788A patent/AU2001231788A1/en not_active Abandoned

Patent Citations (4)

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