INDUSTRIAL PAPER SACK OF THE VALVE TYPE

Abstract

An industrial paper sack of the valve type, includes a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along the direction parallel to the longitudinal axis. The first bottom includes a filling opening of the sack, configured to be sealed after the filling of the sack. The second bottom is folded at a first folding line to form a first folded bottom portion and includes, at a free end of the first folded bottom portion, an emptying opening of the sack. The first folded bottom portion is coupled to the tubular side wall by a removable coupling device.

Description

FIELD OF THE INVENTION

The present invention relates to an industrial paper sack of the valve type.

BACKGROUND

Industrial paper sacks are typically used to package and transport bulk materials of different type, in particular food (e.g., flour), chemical (e.g., granules of plastic material), construction (e.g., cement), agricultural (e.g., seeds), zootechnical (e.g., feed) material, etc.

Industrial paper sacks are divided into two types: sacks of the open type and sacks of the valve type.

The sacks of the open type typically comprise a tubular side wall extending along a longitudinal axis, a closed bottom arranged on one side of the tubular side wall and an end portion arranged on the opposite side of the tubular side wall, said end portion being open to allow the filling of the sack, re-closable upon completed filling and possibly re-openable to allow the emptying of the sack.

Instead, the sacks of the valve type typically comprise a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall and a second bottom arranged on the other side of the tubular side wall.

The first bottom comprises a filling opening (called in technical jargon “valve”) intended to be closed after filling the sack, while the second bottom comprises an emptying opening which, during the filling of the sack, is closed and which is then opened in order to be able to empty the sack.

In order to avoid contamination of the material contained within the sack by external agents, the valve is sealed upon having filled the sack.

The Applicant has focused his attention on the sacks of the valve type.

The Applicant has noted that in this type of sacks the emptying opening is closed for example by gluing or thermal/ultrasonic welding of the paper. When the sack has to be emptied, the user opens the emptying opening by tearing the glued or welded paper.

The Applicant has noted that this opening mode involves several drawbacks.

First of all, at the time of opening the sack, defibrations and/or torn paper and/or glue and/or any other agents present in the external environment could come into contact with the material contained in the sack, with consequent risks of contamination of the material.

In addition, during the sack opening operations, the user’s hands can come into contact with the material contained in the sack, with consequent risks also for the user (depending on the type of material), further to the risk of contamination of the material itself.

It may also happen that the tearing of the glued or welded paper is difficult for some users, with the risk of damaging the sack and spilling a part of the material contained in the sack on the ground.

The problem underlying the present invention is to make an industrial paper sack of the valve type that overcomes the drawbacks discussed above.

SUMMARY

The present invention therefore relates to an industrial paper sack of the valve type, comprising a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along the direction parallel to the longitudinal axis, wherein the first bottom comprises a filling opening of the sack configured to be sealed after the filling of the sack and wherein the second bottom is folded at a first folding line to form a first folded bottom portion and comprises, at a free end of said first folded bottom portion, an emptying opening of the sack, wherein said first folded bottom portion is coupled to said tubular side wall through a removable coupling device.

In the sack of the invention access to the material contained in the sack can only take place after removing the removable coupling device and unfolding the folded first bottom portion. This avoids the risks of contamination of the material in the sack and the risks of accidental contact between the material and the user. This is particularly advantageous when the sack contains e.g., food and/or chemical material.

Thanks to the provision of the removable coupling device, the sack is not damaged during the opening thereof and it is possible to close it again by folding it at the first folding line, thus being able to dose the amount of material removed from the sack from time to time. This is particularly advantageous when the sack contains, for example, agricultural and zootechnical material.

Preferred characteristics of the sack of the present invention are described below. Such characteristics may be provided individually or in combination with each other, unless explicitly stated otherwise.

Preferably, the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to the first folded bottom portion at the first folding line.

More preferably, said removable coupling device is active between said second folded bottom portion and said tubular side wall.

In this way, access to the material contained in the sack can only take place after unfolding the sack first at the second folding line and subsequently at the first folding line, thus further reducing the aforementioned risks of contamination of, and of accidental contact with, the material contained in the sack.

Preferably, the removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall.

The patch is preferably made of paper and may have the same dimensions as or slightly smaller or slightly larger dimensions than those of the second bottom and/or of the tubular side wall.

Preferably, the patch is glued to said second folded bottom portion and to said tubular side wall.

Preferably, the removable coupling device comprises a tear tab.

Opening the sack therefore requires the user to grasp the tab at an end portion thereof, suitably indicated on the sack (for example with an arrow), and then to lift and tear it away from the sack.

The tear tab is preferably formed on the patch.

Preferably, the tear tab is overlapped to said first folding line.

More preferably, when the tear tab is torn, it separates the patch in two opposite portions, one of which remains associated with said second folded bottom portion and the other one remains associated with said tubular side wall. In this way, after the tear tab has been torn off, the user can unfold the second folded bottom portion at the second folding line and subsequently the first folded bottom portion at the first folding line, allowing the sack to be emptied through the emptying opening.

Preferably, said first folding line is substantially orthogonal to the longitudinal axis.

Preferably, said second folding line is substantially orthogonal to the longitudinal axis.

Preferably, said tubular side wall is joined at a gluing line extending along a direction substantially parallel to the longitudinal axis.

Preferably, the sack comprises a front face and a rear face mutually glued at two end portions of the second bottom, said end portions being arranged on opposite sides with respect to the longitudinal axis of the sack.

In this way, when the sack is full it takes on a stiffer and more defined shape.

Preferably, said filling opening is sealed by thermal or ultrasonic welding.

This type of sealing allows the filling opening to be sealed without the supply of welding material. It also prevents leakages of the material contained in the sack after its filling. This is particularly useful when the sack, during handling and use, is repeatedly placed to rest on the first bottom.

Preferably, a coating layer is placed around said filling opening.

The coating layer may be of plastic material or of another kind and may be coupled to a layer of paper arranged around the filling opening by gluing or spreading. Alternatively, the coating layer may be co-extruded with the layer of paper arranged around the filling opening. Such a coating layer allows the filling opening to be closed by thermal or ultrasonic welding.

Preferably, said tubular side wall comprises a plurality of overlapped layers.

Preferably, said overlapped layers are all made of paper.

Alternatively, at least one of said overlapped layers is made of plastic material. The layer in plastic material prevents moisture from entering the sack.

Preferably, in this case, the plastic layer is arranged internally to a layer of paper or interposed between two layers of paper.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become clearer from the following detailed description of preferred embodiments thereof, made with reference to the appended drawings and provided by way of indicative and non-limiting example. In such drawings:

FIG. 1 is a plan view of an industrial paper sack of the valve type in accordance with the present invention in a first operating configuration thereof (sack closed with removable coupling device not removed);

FIG. 2 is a plan view of the sack of FIG. 1 in a second operating configuration thereof (sack closed with removable coupling device removed);

FIG. 3 is a plan view of the sack of FIG. 1 in a third operating configuration thereof (partially unfolded sack);

FIG. 4 is a plan view of the sack of FIG. 1 in a fourth operating configuration thereof (fully unfolded sack).

DETAILED DESCRIPTION

In FIGS. 1-4, an industrial paper sack of the valve type in accordance with the present invention is indicated with reference numeral 10.

The sack 10 comprises a tubular side wall 20 extending along a longitudinal axis X.

A first bottom 30 and a second bottom 40 are formed on opposite sides of the tubular side wall 20 with respect to a direction parallel to the longitudinal axis X.

In FIGS. 1-4 the sack 10 is shown when it is empty, i.e., when it has not yet been filled. The filling material may be of different type, for example flour if the sack 10 is intended for use in the food field, granules of plastic material if the sack 10 is intended for use in the chemical field, cement if the sack 10 is intended for use in the construction field, seeds if the sack 10 is intended for use in the agricultural field, feeds if the sack 10 is intended for use in the zootechnical field, etc.

In FIGS. 1-4 the sack 10 is shown in a flattened configuration thereof.

The sack 10 comprises a front face 11 and a rear face, wherein the term “front” is used to refer to the visible face of FIGS. 1-4 and the term “rear” is used to refer to the hidden face in FIGS. 1-4.

The tubular side wall 20 is formed starting from a sheet of paper, or from a plurality of overlapped layers of paper, which is/are wrapped around the longitudinal axis X to form a tubular structure. The tubular side wall 20 is joined at a gluing line 22 extending along a direction substantially parallel to the longitudinal axis X. In the case of several overlapped layers, different gluing lines may be provided for each layer, the gluing lines possibly being staggered with respect to each other.

In the non-limiting example shown in FIGS. 1-4, the gluing line 22 is provided on the rear side of the sack 10.

In the case of multiple overlapped layers, they are connected to each other (e.g., glued) at respective joining portions. A layer made of plastic material may also be provided, such a layer being overlapped on one or more layers of paper and being arranged internally to a layer of paper or interposed between two layers of paper. The layer of plastic material may also be more than one, in which case each of them is interposed between two respective layers of paper.

The first bottom 30 is formed by conveniently folding a first end portion 30a of the sack 10 and by applying, for example by gluing, a first patch 33 to the folded end portion 30a, the first patch 33 being preferably made of paper. In the non-limiting example of FIGS. 1-4, the first patch 33 has a rectangular shape.

The first patch 33 actually provides the first bottom 30 with a flattened and sufficiently stiff shape, suitable to allow the sack 10 to stand when filled and resting on the ground or on a horizontal plane at the first bottom 30.

The first bottom 30 comprises a filling opening 32 of the sack 10, which defines the so-called valve of the sack 10 and which is configured to be sealed after the filling of the sack 10.

The sealing takes place by thermal welding (in this case, the valve is called “heat-sealing valve”) or ultrasonic welding.

To allow sealing, a coating layer 34, preferably made of plastic material, is placed inside the sack 10 around the filling opening 32.

In particular, the coating layer is glued to a layer of paper arranged around the filling opening 32.

The second bottom 40 comprises an emptying opening 42 of the sack 10 (FIG. 4). The emptying opening 42 is substantially orthogonal to the longitudinal axis X.

The second bottom 40 is folded at a first folding line 44 so as to form a first folded bottom portion 43 (FIG. 3), and subsequently the first folded bottom portion 43 is folded at a second folding line 46 so as to form a second folded bottom portion 45 (FIGS. 1 and 2).

The first folding line 44 is substantially orthogonal to the longitudinal axis X and thus substantially parallel to the emptying opening 42.

The first folding line 44 is arranged at a predetermined distance A from the emptying opening 42 (FIG. 4).

The first folded bottom portion 43 is defined between the first folding line 44 and the emptying opening 42 (FIG. 3).

The emptying opening 42 is defined at a free end of the first folded bottom portion 43, which corresponds to a free end of the sack 10 in its initial shape, before forming the second bottom 40 (FIG. 4).

The second folding line 46 is substantially orthogonal to the longitudinal axis X and thus substantially parallel to the first folding line 44.

The second folding line 46 is arranged at a predetermined distance B from the first folding line 44 (FIGS. 3 and 4).

The second folded bottom portion 45 is defined between the first folding line 44 and the second folding line 46 (FIGS. 1 and 2). The second folded bottom portion 45 is connected to the first folded bottom portion 43 at the first folding line 44.

The distance A is less than or equal to the distance B.

The second bottom 40 comprises a removable coupling device 48 configured to couple the second folded bottom portion 45, or the first folded bottom portion 43 in cases where the second folding is not provided at the second folding line 46, to the tubular side wall 20.

The removable coupling device 48 is formed on a second patch 50 associated with the second bottom 40, in particular with the second folded bottom portion 45, and with the tubular side wall 20.

The removable coupling device 48 comprises a tear tab 52 overlapped on the first folding line 44 and on the tubular side wall portion 20 adjacent to the first folded bottom portion 43, when the first folded bottom portion 43 is folded like in FIGS. 1 and 2.

The tear tab 52 has an end portion 53 adapted to be grasped by the user to lift it and tear it away from the second patch 50. The end portion 53 is indicated for example by a line drawn on the second patch 50 so that it is immediately identified by the user.

When the tear tab 52 is torn (FIG. 2), it separates the second patch 50 in two opposite portions 50a and 50b. The portion 50a is adjacent, on the one hand, to the first folding line 44 and, on the other hand, to the second folding line 46. The portion 50a remains associated with the second folded bottom portion 45, while the portion 50b remains associated with the tubular side wall 20.

In the embodiment shown in the attached figures, the second patch 50 has slightly smaller dimensions than those of the second bottom 40. The second patch 50 is preferably made of paper and is glued to the second bottom 40.

In other embodiments, not shown, the second patch 50 may have substantially the same or slightly larger dimensions than those of the second bottom 40 and/or of the tubular side wall 20.

In the non-limiting example of FIG. 1, the second bottom 40 and the second patch 50 are rectangular in shape. In particular, the second patch 50 has a width slightly smaller than that of the second bottom 40.

In order to provide the filled sack 10 with a stiffer and more defined shape, the front face 11 can be glued to the rear face of the sack 10 at two end portions 24 of the second bottom 40. Such end portions 24 are arranged on opposite sides with respect to the longitudinal axis X.

Only after removing the tear tab 52 and unfolding the second bottom 40 around the two folding lines 44 and 46 one can access to the material contained in the sack 10 and the removal of said material from the sack 10 can take place through the emptying opening 42.

The sack 10 is not damaged following the removal of the tear tab 52 and it is possible, for example, to close it by folding the second bottom 40 at the folding lines 44 and 46 and possibly by applying a new patch 50.

Obviously, in order to meet specific and contingent needs, a person skilled in the art may make numerous modifications and changes to the sack described above, all of which are within the scope of protection of the present invention as defined by the following claims.

For example, only one folding line could be provided instead of the two folding lines 44, 46 of the non-limiting example of FIGS. 1-4.

Or, more than two folding lines could also be provided.

The folded bottom portions 43, 45 of the second bottom 40 may be glued to each other before emptying the sack 10. This arrangement can also be provided in the case of the non-limiting example of FIGS. 1-4.

The patches 33 and 50 may extend only on the front side or only on the rear side or on both sides of the sack 10. In the non-limiting example of FIGS. 1-4, the patches 22 and 50 extend only on the front side of the sack 10.

Claims

1. An industrial paper sack of a valve type, comprising a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along said direction parallel to the longitudinal axis, wherein the first bottom comprises a filling opening of the sack configured to be sealed after the filling of the sack and wherein the second bottom is folded at a first folding line to form a first folded bottom portion and comprises, at a free end of said first folded bottom portion, an emptying opening of the sack, wherein said first folded bottom portion is coupled to said tubular side wall through a removable coupling device.

2. The sack according to claim 1, wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall.

3. The sack according to claim 2, wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall.

4. The sack according to claim 3, wherein said patch is glued to said second folded bottom portion and to said tubular side wall.

5. The sack according to claim 1, wherein said removable coupling device comprises a tear tab.

6. The sack according to claim 5, wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall, and wherein said tear tab is overlapped to said first fold line and, when it is torn, separates said patch in two opposite portions, one of the two opposite portions remains associated with said second folded bottom portion and the other one of the two opposite portions remains associated with said tubular side wall.

7. The sack according to claim 1, wherein said first folding line is substantially orthogonal to the longitudinal axis.

8. The sack according to claim 1, wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall, and wherein said second folding line is substantially orthogonal to the longitudinal axis.

9. The sack according to claim 1, comprising a front face and a rear face mutually glued at two end portions of the second bottom, said end portions being arranged on opposite sides with respect to the longitudinal axis.

10. The sack according to claim 1, wherein said filling opening is sealed by thermal or ultrasonic welding.