EP0075181A1 - Valve bag made of paper for packaging powdered or granular material - Google Patents

Abstract

In the case of a valve sack primarily made of paper, in which the single or multi-layered hose section, preferably provided with gussets, is closed at both ends by folding it once or twice and gluing, and in which the filling valve with the outer filling opening and the inner filling opening (20, 27) is embedded in the longitudinal tube seam, which results between the narrow front flap (18) and the large front flap (14) of the hose section, the valve is preferably placed at the later transition from the sack bottom to the sack front, so that the valve is in the filled sack comes to lie arched, with which the pressure of the filling material supports the safe closing of the valve. The valve itself is obtained from a separate valve sheet. A valve shape that takes the form of a “9” by folding twice or the shape of a “Q” by folding three times achieves a special strength for the valve. A cover strip (2, 4, 30) glued to the longitudinal seam of the valve bag in the area of the valve gives the valve bag the desired high strength for filling via a filler neck.

Description

The invention relates to a box-shaped, single-layer or multi-layer paper bag in the filled state, which is closed at both ends by a single, single or double-folded wrapping messenger.

Prefabricated bags, i.e. bags which are already closed at both ends and provided with a self-closing valve for filling, are generally referred to as valve bags.

Such sacks have found widespread use for packaging powdery or granular goods, because in this way even sensitive goods can be filled into self-sealing pre-made sacks without the need for a further closing process after the filling process.

Valve bags of the previous embodiment are shown in FIGS. 1 to 6.

Figures 1 to 3 show a valve bag, in each of which the two open, flat ends of the tube section are covered with a folded paper flap 4, 6 and sewn to the thread seam 5 with this. Fig. 1 shows specifically the front view of this sewn valve sack, with 1 the back of the sack, 2 the front of the sack, with .3a and 3b the folded sides of the unfilled sack are shown. Fig. 2 shows specifically with 7 the before completion of the sack in the open tube section protruding folded tab, which is turned in before the application of the folded tab 6, as indicated in Fig. 2 with an arrow, and thus after sewing the sack, the valve 8 (Fig. 1) with the inner Filling opening 9 results. 3 shows this sewn sack in the filled state, in which the side folds 3a, 3b in FIG. 1, which are still almost flat, have now opened to the narrow side of the sack which is almost box-shaped in the filled state. The valve 7, 8, which is folded in directly from the paper tube, results in a slight shortening L (FIG. 3) in the area of the valve when the sack is filled, in the area of which the closure flap 6 hangs freely, so that the end of the sack is not sewn inevitably, but through the inserted valve tube is still closed.

The sewn valve sack shown in FIGS. 1-3 has the advantage of sack ends of very simple shape on both sides; However, it has the disadvantage that the many holes in the two thread seams 5 cause high stresses in the filled state and the bag is also not powder-tight.

4 to 6, on the other hand, a complicated shaped sack is shown, which is distinguished from the sewn valve sack by a cross bottom formed at both ends of the initially open paper tube. In one of the two cross bases there is also a valve hose wound and glued from a sheet of paper, which results in the filling valve for this valve bag. Fi ^{q ..} 6 specifically shows the still open valve sheet 1, which in the two lines 2a, 2a 'and the line 2b is pre-folded before it is first folded in the upper line 2a and then in the lower line 2a', so that a tube is formed. The shorter flap 4 is pre-glued in such a way that the flap 4 is glued to the flap 1 in regions after folding in the two lines 2a, 2a '. 4 in such a way that the tabs 1 with 4 in the form shown form the underside of the valve and the area 3 with the thumb deflection 3a forms the top of the valve. As can also be seen in FIG. 4, the valve hose is inserted into the base A and glued before the tabs 6b and 6a are folded over and also glued. The valve is initially with the corners 7 and 8 beyond the bottom triangle. After the valve bag has been filled, however, the valve is preferably wrapped or folded over in the pre-break line 2b and additionally closed and sealed with an adhesive flap 9a of a bottom cover sheet 9 (FIG. 5). This valve bag according to FIGS. 4-6 is made from the hose section 5, which in this case, in contrast to the sewn valve bag according to FIGS. 1-3, has no lateral folds, from the valve sheet according to FIG. 6 and the bottom cover sheet 9.

This valve bag, which is provided with a cross bottom at both ends, is more suitable for packaging particularly sensitive goods than the sewn valve bag according to FIGS. 1-3, since it has better powder tightness. However, the bottom of the cross has turned corners, which are also called "negative corners" and cannot be glued. This leaves open channels in the cross floor through which pulverulent material is formed under unfavorable conditions can trickle. Complete powder tightness is only achieved with the additional cover sheet 9 as shown in Figure 5. Compared to the sewn valve sack, the cross-shaped valve sack according to Fig. 4 - 6 is considerably more expensive to manufacture than the sewn valve sack due to the complicated shape of the cross bottoms and the possibly additionally applied cover sheet 9.

The invention is therefore based on the object of creating a valve bag which, on the one hand, can be produced very economically and, on the other hand, has the advantages of the cross-bottom valve bag, but which also has an absolutely tight base without an additional cover sheet.

The solution according to the invention is specified in claim 1.

Advantageous further developments are characterized in the subclaims.

Starting from a paper sack with a valve according to the type mentioned at the outset, the invention therefore consists in the fact that a tubular valve made of paper and glued into itself is embedded in the longitudinal seam of the open paper web, preferably in the vicinity of one of the two winding trays , through which the closed paper bag can be filled with the powdery or granular material to be packed, for example via a filler neck of a filling machine.

The object of the invention is therefore a paper valve bag, which consists of one or more flat tubes with two side gussets folded and longitudinally glued paper layers, in which the two open ends of the respective tube section are folded over or glued and glued and sealed in this way, and in which a valve is inserted transversely to the longitudinal glue seam in the longitudinal tube seam in the area of one of the two "winding bottoms" is, wherein the valve is in turn made of a folded-over to a tube section and glued paper section. To increase the strength of this paper valve sack, a cover sheet is stuck in the area of the recessed valve.

The invention and advantageous details are explained in more detail below with reference to the drawing in exemplary embodiments.

• Fig. 1 bis 6 bereits beschriebene bekannte Ausführungsformen von Papiersäcken mit Ventil;
• Fig. 7 die Vorderansicht eines Papier-Ventilsacks mit erfindungsgemäßen Merkmalen;
• Fig. 8 bis 11 einzelne Schritte zur Herstellung des Ventilsacks nach Fig. 7;
• Fig. 12 den Ventilbereich eines erfindungsgemäßen Ventilsacks im Zustand des Befüllens mit einem eingelassenen Füllstutzen 23;
• Fig. 13 den gefüllten Ventilsack mit selbstverschlossenem Ventil, das sich durch den von innen wirkenden Druck des Füllguts selbst verschlossen hat;
• Fig. 14 den gefüllten Ventilsack in Gesamtansicht;
• Fig. 15 einen Ventilsack gemäß der Erfindung mit einem in die Längsnaht eingelassenen Ventil;
• Fig. 16 und 17 Einzelheiten des Ventilsacks gemäß Fig. 15;
• Fig. 18 einen ähnlichen Ventilsack wie Fig. 15, jedoch mit einem anderen Ventil;
• Fig. 19 und 20 Einzelheiten des Ventilsacks nach Fig. 18;
• Fig. 21 ein offenes Papierblatt, aus dem ein Ventil für einen erfindungsgemäßen Ventilsack geformt wird;
• Fig. 22 bis 29 weitere vorteilhafte Ventilformen.

Show it

• Figures 1 to 6 already described known embodiments of paper bags with valve.
• 7 shows the front view of a paper valve sack with features according to the invention;
• 8 to 11 individual steps for the production of the valve bag according to FIG. 7;
• 12 shows the valve area of a valve sack according to the invention in the state of being filled with an embedded filler neck 23;
• 13 shows the filled valve bag with a self-closing valve, which has closed itself due to the pressure of the filling material acting from the inside;
• 14 shows the filled valve bag in an overall view;
• 15 shows a valve bag according to the invention with a valve embedded in the longitudinal seam;
• 16 and 17 details of the valve bag according to FIG. 15;
• FIG. 18 shows a valve bag similar to FIG. 15, but with a different valve;
• 19 and 20 details of the valve bag of FIG. 18;
• 21 shows an open paper sheet from which a valve for a valve bag according to the invention is formed;
• 22 to 29 further advantageous valve shapes.

FIG. 8 first illustrates the hose section according to FIG. 9, which has been unfolded again. FIG. 9 shows the hose section with the longitudinal glue seam on the front. Fig. 8 illustrates the three 12a, 12b longitudinal fold lines in the area of the later two narrow sides of the box-shaped filled valve bag, which form the side folds in the valve bag or bag section lying flat. A narrow flap 15 is glued in the longitudinal seam to a wider front flap 11, while the back 10 of the hose section and the later valve sack remains smooth. The hose ends are cut in steps; to close the two hose ends, a tab 17 in FIG. 9 is folded over and glued to the back and a tab 13. 9 also shows a partially opened longitudinal seam. This is before the folding of the Tab 17 introduced a pre-folded valve sheet to close the upper section line. Fig. 10 illustrates the pre-folded valve sheet 16, which is introduced into the open longitudinal seam in such a way that when the upper closing flap 17 is later folded over, it is also folded over into a line of interruption 22. 11 shows the valve which has been introduced and glued in, with the front valve opening 18 and the valve inlet opening 19 inside the bag. The valve is introduced in front of the left side fold with a break line 21 and a cover sheet 20 is finally stuck on to stiffen the valve area. The finished valve bag in the front view is shown in Fig. 7.

FIG. 12 shows the aforementioned individual elements in the region of the valve in their position during filling and in FIG. 13 after the valve has closed itself. While the two FIGS. 12 and 13 show sections of the sack in individual representation, the filled valve sack is shown in an overall view in FIG. 14.

From Fig. 8 and Fig. 9 it is additionally clear that to close the two ends of the hose section by simply turning and gluing the hose section at both ends must be cut stepwise. So that there is no material waste when cutting the hose section, this inevitably results in the fact that the locking tab 17 according to FIG. 9 must protrude from the front section edge and the front tab 13 must protrude from the rear section edge. According to FIG. 9, it then emerges that the tab 17 moves forward in the break line 22 beat while the flap 13 is to be turned back to close the lower bag section.

Fig. 7 shows a valve bag according to the invention, in which the bottom closing flap to be folded does not carry the longitudinal seam and consequently the bottom flap is to be turned over in the direction of the valve.

The one or two folds and gluing of the two open ends of the tube section first gives a wrap closure. The actual rectangular bottom of the valve bag only forms when the valve bag is filled, and it forms in the rectangular dimensions

(Width of the flat lying (twice the depth of the hose) gusset or stretched gusset).

According to the present invention, the above-mentioned valve is preferably positioned in the longitudinal seam so that the valve is in the transition from the front of the bag to the bottom of the bag after the valve bag has been filled. The valve is therefore no longer flat, but is curved, as can be seen from FIGS. 13 and 14.

Geometrically, this means that in the manufacture of the valve bag according to the invention, the center of the flat valve tube lies at a distance of approximately one side fold depth from the inner, i.e. the wrapping bottom fold line facing the sack is to be introduced into the longitudinal seam.

In Fig. 15, however, a valve bag is reproduced in accordance with the invention with a recessed into the longitudinal seam valve in which the County snahtseite ^g in the tube section, the projecting tab results and consequently, the bottom flap from the valve's turn over away. Fig. 18 shows a valve bag according to Fig. 15, but with a different valve. 16 and 17 or 19 and 20 each illustrate individual parts of the valve bags shown in FIGS. 15 and 18.

The valve bag according to FIG. 15 has a valve which according to FIG. 17 has the shape of a "9" in the open state. In contrast, the valve of the valve bag according to FIG. 18 has the shape of a "Q" in the open state, as can be seen from FIG. 20.

The figures show the following elements: The front A shows the short front flap at 18 and the long front flap at 14, which are glued together in the longitudinal glue seam, which is not further numbered. The smooth side of the valve bag is numbered 13. The folded-in pages are identified by 15a and 15b and 16 and 17 show the lower and upper protruding flaps, respectively, which have to be turned over and glued to close the respective section end, with flap 17 turning backwards and flap 16 forward is. 15-17 shows the outer inlet opening at 22 and the inner inlet opening at 20. 17 with the right side according to Fig. 17 against the tab 18 and with the left side according to Fig. 17 against the tab 14. With the protruding tab 19 the valve bag is reinforced in the valve area and the incision 23 ensures that the inner Valve proboscis remains more flexible, which benefits the valve's ability to close. To reinforce the entire valve area, a reinforcement sheet 24 is glued to the finished valve bag according to FIG. 15 and a self-adhesive tape 25 closes and protects the valve before and after the valve bag is filled. The valve bag according to FIGS. 18 and 20 has only changes in the valve compared to the valve bag according to FIGS. 15-17; in this case it is Q-shaped. The inevitably given double tab 26 must be glued in, as shown in Fig. 20. 15-17, it gives the valve bag in the valve area greater strength. The outer filler opening of the valve is identified by 31 and the inner one by 27. 20 is glued to the right side with the tab 18 and with the left side to the tab 14 of the paper tube section. An inner incision 32 in turn ensures greater freedom of movement and shape of the inner valve trunk, which benefits the sealing property. A special feature of this valve is a tube 29 which is also spread when the valve is open according to FIG. 20 and from which excess air can escape through the opening 31 during the filling process of the valve bag. When the sack is filled, the filling material presses the valve flat so that both the valve tube, formed by the inlet opening 31 and the inner outlet opening-27, and the tube 29 are closed. A cover sheet 30 is again applied to reinforce the valve bag in the valve area and the cover sheet 33, which is preferably designed as an adhesive tape, serves to protect and to close the valve in an absolutely powder-tight manner before and after the filling process.

Further advantageous valve shapes are shown in FIGS. 21-23 or 24-26 and 27-29.

Figure 21 shows the open paper sheet from which the valve is formed. The two lines 12a, 12a 'show two transverse pre-break lines and the line 12b, which extends from the lower paper edge to the lower pre-break line 12a', shows a vertical pre-break line. Continuing the lower pre-break line 12b, the line 16 represents an incision. To form the valve, the tab 17 is folded forward in the pre-break line 12a and in "step 2" the tab 15 with the front tab 14 and the already folded-over tab 17 in the lower break line 12a turned over so that the tab 17 comes to rest on the lower edge of the tab 11. In this way, the surface 10 according to FIG. 21 forms the valve underside: in FIG. 22, the surface 13 according to FIG. 21 forms the valve top in FIG. 22, while the tab 17 according to FIG. 21 forms an intermediate layer in FIG. 22. FIG. 23 shows how this valve is introduced into a valve bag according to FIGS. 15 and 18. The edge B according to FIG. 22 forms the lower edge of the valve in FIG. 23, the surface 13 forms the valve path glued from the inside to the long upper flap 20 of the bag section, while the surface 10 according to FIG. 21 in some areas with the short flap 23 according to FIG. 23 is glued. The area 11 according to FIGS. 21 and 22, which lies in the plane of the valve underside, is not glued to the tab 23 of the hose section.

The valve bag shown in the top view 23 is filled through the incision 16. After the valve bag has been filled, the valve can be opened with the tab 14 and 18 in the broken line 12b or in the cut open NEN line 16 folded and glued to the long tab of the longitudinal seam side of the bag section 20. In FIG. 23, 21 shows the upper bottom flap turned backwards and 22 the lower bottom flap turned forward. At 19, reference is made to the back of the bag.

An advantageous addition to the valve according to FIGS. 21 and 22 is shown in FIG. 24. With the self-adhesive strip 18a, the foldable part of the valve can advantageously be glued to the large flap on the longitudinal seam side of the valve bag. An additional, additional adhesive tape 25 provides further security.

In Fig. 26 it is shown that this valve can also advantageously be introduced into a cross-bottom bag, the valve being introduced not in the longitudinal seam but in the bottom of the valve bag, in contrast to the previous pictures. The designations apply analogously to FIGS. 4, 5 and 21 to 25.

A further advantageous variant of the valve is shown in FIGS. 27 to 29. In the fully folded and self-adhesive state according to FIG. 28, it corresponds to the 9-shaped valve according to FIG. 17 with the special additions according to FIGS. 21, 22 and 24.

Compared to the valve sheet according to FIG. 21, the valve sheet 27 is extended, so that a lower tab 30 protrudes beyond the later valve rear side 28, which is glued on both sides according to tab 19 according to FIGS. 15 to 18 in the longitudinal seam of the valve bag and thus the valve bag in Valve area gives greater strength. In analogous transmission, the lower edge B of the tab 30 now forms the lower edge of the valve in the valve bag according to FIG. 23.

The area 29 of the open valve sheet according to FIG. 27, like the area 11 according to FIG. 21, cannot be glued to the shorter tab of the hose section 23 according to FIG. 23. The areas 14, 29 and part of the area 17 are turned over as the area 31 according to FIG. 28 in the lines 12b and 16 for later closing of the valve, the handling being advantageously facilitated with a self-adhesive application 32.

Claims (9)

1. Single or multi-layer paper valve bag, characterized in that the valve bag is closed at both ends with a staggered cut by a single and a smooth cut by double folding and gluing and in the area of one of the two bottoms in the longitudinal seam a valve forming a tube is glued in, through which the paper bag can be filled and which closes itself after filling due to the pressure effect of the filling material. 2. Valve sack according to claim 1, characterized in that the valve is positioned in the longitudinal tube seam such that it is in the finished valve sack in the transition from sack bottom to sack front which forms during filling and in this way comes to lie arched in the filled sack. 3. Valve bag according to claim 1 or 2, characterized in that a folded sheet of paper is glued into the upper region of the longitudinal seam of the open tube section such that the one tab of the inserted paper with the outside of the short tab of the tube section and the other tab of the inserted paper is glued to the inside of the long flap of the tube section in the area of the longitudinal seam _/ and that the open side of the simply folded inserted paper is folded and glued to the longitudinal seam side of the tube section with the longer flap of the tube section to be folded over. 4. Valve bag according to one of the preceding claims, characterized in that the single cross-folded valve sheet to be inserted is longitudinally folded in advance for stiffening, so that the valve fill opening is not provided by a paper edge but by a paper fold edge. 5. Valve bag according to one of the preceding claims, characterized in that a cover sheet is glued to the longitudinal seam in the region of the valve to reinforce the valve region. 6. Valve bag according to claim 1 or 2, characterized in that a previously folded into a U-shape and glued paper section is glued to the end of the paper tube section in the longitudinal seam, on which the longitudinal seam-side surface of the tube section forms the protruding tab of the relay section and folded and glued to close the bottom to the side facing away from the valve. 7. Valve bag according to one of the preceding claims, characterized in that the pre-folded and glued in the longitudinal seam valve is Q-shaped such that an inner reinforcing tab of the valve is formed and a triangular trachea is formed for filling the valve bag, from the excess air can leak. 8. Valve bag according to claim 1, 6 or 7, characterized in that the valve formed into a flat tube and pre-glued valve contains a second cut and fold line, which is not glued to the tube section and after filling the valve bag a foldable and with the Valve bag glued tab forms such that the valve can be firmly closed after the filling process. 9. Valve bag according to claim 8, characterized in that the valve has a further projecting tab which gives the pre-folded and pre-glued valve to the shape of a "9" and gives the valve bag with the projecting valve tab in the valve area greater strength.

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