GB2031848A - Water-proof valved bag - Google Patents

Abstract

A bag for containing liquids has a one-way inlet valve formed by outer layers (5,6) having their free edges (5', 6') bent over in U-shape one within the other, and two or more inner layers (7,8) of successively less width. All the layers and one side wall (1) of the bag are joined along two mutually perpendicular weld lines 9,10 and all the layers, except for the one (6) remote from the side wall, and the side wall are joined by another weld line 12 and are cut to provide an inlet slit (11). <IMAGE>

Description

SPECIFICATION Water-proof valved bag This invention relates to bags of plastics material of the type so called "Valve" type which are waterproof and are used for liquids.

Film or tubular plastics material bags have bee proposed which are completely closed type except for a pocket used for filling so as to avoid loss of material. Such valve bags are very suitable for granular material and powder, but they are very often not successful for holding liquid materials, particularly those of low density. For liquid materials, bags provided with valve obtained from a series of sheets bent to form a check valve, were proposed but in practice such valve were difficult to make by means of industrial procedures suitable for large mechanized batch production.

In the present invention there is provided a multi-layer valve bag wherein at leasttwo of the layers are bent to form a U along a free edge and the other layers being joined thereto are super-imposed thereon and are of different lengths to form a series of barriers which prevent loss of the contained material even if it is liquid.

This invention will be better understood from the following description of an embodiment shown in the accompanying drawings wherein: Figure 1 shows a perspective view, opened as the leaves of a book, of the location of various sheets forming a valve bag in accordance with the invention.

Figure 2 shows a perspective view of the bag.

The bag basically formed by two sheets respectively indicated at 1 and 2 which are joined along the four sides by means of welding or other known means to form the opposite sides of a single tubular element which is sealed by welding along a bottom line 3 and a top line 4 which extends across the full width of the bag.

The bag valve comprises several layers, two of which form opposite sides of the valve and are indicated at 5 and 6 (see Figure 1) and have free edges 5' and 6' bent over in a U-shape one inside the other, edge 5' being inside edge 6'. Between the two layers 5 and 6 there is provided a plurality of further layers, the widths of which are different and less than the layers 5 and 6 as shown at 7 and 8.

All the layers are welded together in a single operation and also to the sheet 1 along a side welding line 9, a lower line 10 joinirg the line 9 and also by the already mentioned transverse welding line 4. The valve is completed by a slit formed by cutting along line 11 through layer 1 and layers 5, 7, and 8 but not layer 6.

There is also a welding line 12 parallel to inlet slit 11 and which also joins layer 1 to all the other layers with the exception of layer 6.

The operation of the valve bag in accordance with the invention is as follows. The material to be bagged is inserted through inlet slit 11 and without obstruction passes between the set of layers 8-7-5 on one side and layer 6 on the other side, and then passes in a reverse direction around the two Ubends 5' and 6' to get to the inside of the bag. Once the filling is complete the valve layers prevent any loss of the contained material even if it is very fluid.

Initially any material is stopped from getting out of the bag by the folded edges 5' and 6' which are squeezed one against the other by the pressure of the contained material. In case, incidentally, any material should pass the barrier made by the edges 5', 6', it then meets the barrier of layer 7 which is squeezed against sheet 6, then the layer 8 and so on if more than two such layers are present.

It has been found that the valve is perfectly proof against loss of water and other liquids such as industrial alcohol for example.

Obviously, the bag dimensions, kind of filling, number of valve layers 7 and 8 or 5 and 6 will be depending on particular needs.

Water-proof valved bag 1. A valve bag including a one way inlet valve comprising a plurality of layers two of which are longer than the rest and have free edges bent over in a U-shape one within the other, the remaining layers being successively narrower.

2. A valve bag according to claim 1, wherein the said two layers are external to the rest of the layers of various lengths.

3. A valve bag according to claim 2, wherein the set of layers are welded together to one side and wall of the bag along two mutuaily perpendicular lines and an inlet is provided by cutting a slit through the said side wall and all the layers except for the last layer adjacent to the opposite side wall of the bag.

4. A valve bag according to claim 4 wherein the set of layers, except for the said last layer, and the said side wall are welded together along a line disposed on the opposite side of the inlet slit to one of said mutually perpendicular weld lines.

5. A valve bag constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Water-proof valved bag This invention relates to bags of plastics material of the type so called "Valve" type which are waterproof and are used for liquids. Film or tubular plastics material bags have bee proposed which are completely closed type except for a pocket used for filling so as to avoid loss of material. Such valve bags are very suitable for granular material and powder, but they are very often not successful for holding liquid materials, particularly those of low density. For liquid materials, bags provided with valve obtained from a series of sheets bent to form a check valve, were proposed but in practice such valve were difficult to make by means of industrial procedures suitable for large mechanized batch production. In the present invention there is provided a multi-layer valve bag wherein at leasttwo of the layers are bent to form a U along a free edge and the other layers being joined thereto are super-imposed thereon and are of different lengths to form a series of barriers which prevent loss of the contained material even if it is liquid. This invention will be better understood from the following description of an embodiment shown in the accompanying drawings wherein: Figure 1 shows a perspective view, opened as the leaves of a book, of the location of various sheets forming a valve bag in accordance with the invention. Figure 2 shows a perspective view of the bag. The bag basically formed by two sheets respectively indicated at 1 and 2 which are joined along the four sides by means of welding or other known means to form the opposite sides of a single tubular element which is sealed by welding along a bottom line 3 and a top line 4 which extends across the full width of the bag. The bag valve comprises several layers, two of which form opposite sides of the valve and are indicated at 5 and 6 (see Figure 1) and have free edges 5' and 6' bent over in a U-shape one inside the other, edge 5' being inside edge 6'. Between the two layers 5 and 6 there is provided a plurality of further layers, the widths of which are different and less than the layers 5 and 6 as shown at 7 and 8. All the layers are welded together in a single operation and also to the sheet 1 along a side welding line 9, a lower line 10 joinirg the line 9 and also by the already mentioned transverse welding line 4. The valve is completed by a slit formed by cutting along line 11 through layer 1 and layers 5, 7, and 8 but not layer 6. There is also a welding line 12 parallel to inlet slit 11 and which also joins layer 1 to all the other layers with the exception of layer 6. The operation of the valve bag in accordance with the invention is as follows. The material to be bagged is inserted through inlet slit 11 and without obstruction passes between the set of layers 8-7-5 on one side and layer 6 on the other side, and then passes in a reverse direction around the two Ubends 5' and 6' to get to the inside of the bag. Once the filling is complete the valve layers prevent any loss of the contained material even if it is very fluid. Initially any material is stopped from getting out of the bag by the folded edges 5' and 6' which are squeezed one against the other by the pressure of the contained material. In case, incidentally, any material should pass the barrier made by the edges 5', 6', it then meets the barrier of layer 7 which is squeezed against sheet 6, then the layer 8 and so on if more than two such layers are present. It has been found that the valve is perfectly proof against loss of water and other liquids such as industrial alcohol for example. Obviously, the bag dimensions, kind of filling, number of valve layers 7 and 8 or 5 and 6 will be depending on particular needs. CLAIMS Water-proof valved bag

1. A valve bag including a one way inlet valve comprising a plurality of layers two of which are longer than the rest and have free edges bent over in a U-shape one within the other, the remaining layers being successively narrower.

2. A valve bag according to claim 1, wherein the said two layers are external to the rest of the layers of various lengths.

3. A valve bag according to claim 2, wherein the set of layers are welded together to one side and wall of the bag along two mutuaily perpendicular lines and an inlet is provided by cutting a slit through the said side wall and all the layers except for the last layer adjacent to the opposite side wall of the bag.

4. A valve bag according to claim 4 wherein the set of layers, except for the said last layer, and the said side wall are welded together along a line disposed on the opposite side of the inlet slit to one of said mutually perpendicular weld lines.

5. A valve bag constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.