GB2081213A

GB2081213A - Flexible bulk container

Info

Publication number: GB2081213A
Application number: GB8025597A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-08-06
Filing date: 1980-08-06
Publication date: 1982-02-17
Also published as: GB2081213B

Abstract

A flexible bulk container of woven fabric comprising a base, side walls and a top having means by which the container may be lifted but having no opening. The base has an opening through which the container may be filled in an inverted position and emptied in its normal position. The container may include an inner liner having a closed top 12 secured to the top of the bag and an opening associated with the opening in the base. A modified container consists of a folded sheet of material stitched as shown in Fig. 5 to form a lifting tube 31, 35 and having a filling aperture in the base 34. <IMAGE>

Description

SPECIFICATION Flexible bulk container This invention relates to a flexible bulk container.

The use of flexible containers in the storage and transport of powdered or other materials is becoming increasingly widespread. The containers are generally in the form of large bags or sacks made from woven fabric and the general basic requirements of such containers are that they can be lifted by forklift truck and by crane, have a good factor of safety and are inexpensive to manufacture. The containers are usually designated as being suitable for a given weight and are currently manufactured for accepting loads of half tonne, one tonne and more.

Woven fabric containers for such use comprise a base, side walls and a top, there being means at the top of the container by way of which the container may be lifted. Such containers are filled from the top and emptied from the bottom either by cutting open the base of the container or by way of a special discharge arrangement formed in the base to render the container capable of being reused.

Broadly stated there are two basic types of such container currently in use, although many variations within these basic types are found. In the first such type the lifting means at the top of the container is formed by way of one or more loops of material secured to the sidewalls of the container, for example by stitching. Many different arrangements of lifting loops are known and they are arranged so that they do not interfere with the filling of the bag through the top thereof. Clearly it is necessary for there to be a cover over the top of the bag in order to protect the contents therein and such covers must be of a nature to allow filling of the bag therethrough.Two forms of cover are in general use, the first of these being known as a skirt, which is a voluminous piece of fabric covering the top of the bag and having its edges stitched to the bag walls at or adjacent to the upper edges thereof around the full perimeter of the top of the bag. The skirt has a central opening for filling purposes and has sufficient fullness of material so that when the bag has been filled the skirt may be folded and tied off to-prevent ingress of unwanted liquid or solid material. The amount of material required for the skirt and the separate operation of stitching the skirt to the sidewalls of the container significantly increase the cost of the container. The second arrangement utilises a piece of material designed to fit closely the open space at the top of the bag and again stitched around its edges at or adjacent to the sidewalls of the bag.The piece of material is formed with a central hole and a tube is stitched to the periphery of this hole to form a guided filling opening into the bag. After filling the tube can be tied off to prevent ingress of unwanted liquid or solid materials. The formation of the tube and the stiching operation for this sheet of material again adds to the cost of the bag.

The second general type of bag is one that does not utilise separate lifting loops, but effects lifting of the bag on one or more loops formed by extensions of the material that actually constitutes the sidewalls of the bag. Thus, either one or two layers of bag sidewall material lie at the top of the bag and openings must be cut in these layers in order to allow filling of the bag. Such openings ideally need to be hemmed and they may also need filling tubes stitching thereto, resulting in extra operations during the manufacture of the bag. Furthermore the openings materially weaken the lifting fabric and lead to the possibility of the container being mishandled when in use.

The flexible bulk containers to which the invention relates are usually provided with an inner liner of impervious material which has the dual effect of preventing fine material leaking through the bag fabric and of protecting the material from moisture that may seep through the bag fabric. Such liners are commonly in the form of a tube of plastic material one tubular section of which is extended through the filling opening in the top of the bag in order that the liner may be filled and another tubular section of which extends through a discharge structure at the base of the bag in order that the bag may be emptied. Prior to filling the bag the tubular section at the lower end of the liner is tied off and folded within the base of the bag which is also closed by whatever closure means are provided.Filling can then be accomplished without leakage of the material from the base of the container. It is often found that in the filled bag the weight and distribution of material traps and distorts the tubular section at the bottom of the liner and substantial difficulty is often experienced in freeing this lower tubular section when the bag is to be emptied. Ofte the bottom of the bag has to be cut away so rendering the bag incapable of further use.

The present invention provides a bag designed to be used in a completely novel and unexpected manner to avoid the disadvantages that have been previously referred to.

According to the present invention a flexible bulk container of woven fabric comprises a base, sidewalls and a top, and means at the top of the container by way of which the container may be lifted; the base of the container has an opening through which the container may be filled with the container in an inverted position and emptied with the container in its normal position, means are provided for closing the opening, and the top of the container is completely closed and devoid of any filling opening.

The basis of the invention is thus that the top of the container is completely closed and the container must be inverted for filling purposes.

This means that in the type of container having lifting loops the top of the container may be closed by a simple sheet of material fitting closely within the top of the container and stitched or otherwise secured to the container's sides. There is no opening in this top, no need for any filling tube attachment and no need for any voluminous skirt.

In the type of the container where the sidewalls or an extension thereof form the lifting loop these walls may be continuous and need not be weakend in any way by the cutting of an opening through which the container is to be filled.

In one embodiment of the invention the container includes an inner liner of impervious material arranged within the container for receiving the material to be carried, the liner being closed at the top thereof and having an opening associated with the opening in the base of the container through which the liner may be filled and emptied, means being provided for closing the opening in the liner.

The liner is thus filled and emptied through the same single opening at the base of the bag. Filling takes place in the inverted position and it is a simple matter to arrange the liner during filling so that the tubular section protruding from the base of the container remains free and can be folded and tied off exactly as required. This makes possible careful positioning of the tubular section so that it is readily accessible when the container comes to be emptied.

Preferably the liner is secured in the container by securing the top of the liner to the top of the container. For example the liner may be a length of tubular material having a top tubular section tied off and secured to the container top, the filling and emptying opening being an open-ended tubular section at the bottom of the liner extending through a hole in the base of the container and capable of being closed as required. The container will then usually include means at the base thereof for protecting the closed tubular end of the liner.

In order that the invention may be better understood specific embodiments of containers in accordance therewith will now be described in more detail, by way of example only, with reference to the accompanying drawings in which Figures 1 and 2 show different views of a first embodiment of container; Figure 3 is a detail view of part of the base of the container of Figures 1 and 2; Figures 4 and 5 are schematic Figures illustrating how a second embodiment of container may be made; Figure 6 is a view of this second embodiment of container; and Figures 7 and 8 are two different views of a third embodiment of container.

Figure 1 shows a container manufactured from woven fabric such as a high tenacity synthetic fibre, of which polypropylene is a particularly suitable example. Sheets of such fabric are stitched together to form a bag which has a base 1, a first pair of opposed sidewalls 2, 3, a second pair of opposed sidewalls 4, 5 and a top 6. The base 1 and the sidewalls 2 and 3 are formed from a single length of woven fabric folded to a U-shape, and each sidewall 4, 5 is secured to the base by stitching and also secured to the adjacent sidewalls 2, 3 by stitching. The top 6 may be formed by a separate piece of fabric stitched along its four edges to the respective upper edges of the sidewalls 2 to 5 in order completely to close the top of the bag. It should be particularly noted that the top 6 is devoid of any opening into the bag.As an alternative to using a separate sheet of material for the top 6 that top may be integral with sidewalls 4 and 5, the container then being constructed from two relatively inverted U-shaped lengths of fabric suitably stitched together.

Secured to the top of the bag by stitching are four lifting loops 7 to 10 designed to be engaged by the tines of a forklift truck or to be connected by a suitable length or legnths of material that will form a lift point for the hook of a crane. Figures 1 and 2 merely show one example of the multiplicity of different ways in which lifting loops can be secured to the top of a bag and any suitable method employing any required number of loops may in practice be adopted.

Fitted within the container and shown in broken outline in Figures 1 and 2 is a tubular liner 11 of impervious material, such as polyethylene. The liner is gathered together at the top of the bag to form a top tubular section 12 which is knotted or otherwise tied off to close the upper end of the liner. The liner may be held in place at the top of the container by a flexible plastics clip 13 engaging part of the liner and passing through the fabric forming the top 6 of the bag. Securing means other than the clip 13, for example adhesive materials, can alternatively be used.

At the base of the bag the liner is again folded together to form a base tubular section 14. This is associated with an opening 1 6 formed in the base of the bag, a protective fabric tube 1 7 being stitched to the base around the opening 1 6. The opening 16 may be a simple cut hole, but in one particularly suitable arrangement the opening is formed by making two intersecting cuts at rightangles one to another in the bag base, folding back the pointed section of each of the resulting four flaps onto the body of the flap and stitching the pointed section 1 8 of the flap body 1 9. On each of the four flaps a tunnel 20 is thus formed and a drawstring 21 may be threaded through the four tunnels so that the opening may be restricted as required.

In conventional bags having lifting loops at the top of the bag the usual practice on filling the bag would be to close the bottom end of the liner and close any other openings at the base of the bag in order that the liner is properly protected. Material would be filled into the liner through the top tubular section of the liner brought through a filling opening in the top of the bag. As already explained, in a bag according to the invention, the top of the bag is devoid of any filling opening. In use, therefore, in order to fill the bag the bag must be inverted to the position shown in Figure 2.

During filling desirably the top wall of the bag rests on the ground or some other suitable support and the bag is temporarily suspended by its base, for example by clips hooks or any other suitable means. The only weight that need be supported in this condition is the weight of the bag itself. The base tubular section 14 of the liner 11 is brought through the opening 1 6 in th base of the bag and out from the protective tube 1 7 as shown in Figure 2. The free end of the section 14 may then be secured to a hopper or any other filling means and material filled into the cohtainer. After filling the tubular section 14 is knotted, and secured by a removable tie 22 and is tucked inside the protective tube 1 7 as shown in Figure 3.The section 14 can be carefully arranged within this tube so that it may be readily accessible when the container is to be emptied. After arranging the section 14 the hole 1 6 is closed by the drawstring 21 and the protective tube 17 is closed and secured by a tie or clip 23. The base of the bag is thus sealed. The filled bag can then be turned the right way up and handled in the conventional manner by either forklift truck or crane. When the container is to be emptied it is suspended by the lifting loops in the normal way, the protective tube 1 7 is opened, the drawstring 21 released to open the hole 1 6 in the base of the bag, the base tubular section 14 of the liner is released and opened and material can then flow from the container. Thus, during emptying the container is inverted from the form shown in Figure 2.

Figures 4 and 5 show how a second embodiment of container may be manufactured extremely simply from a single sheet 30 of woven fabric. The sheet is folded along a fold line 31 to double thickness and the two thicknesses are stitched together along side seams 32, 33 and a base seam 34. The side seams 32, 33 stop short of the fold line 31 and an additional row of stitching 35 secures the two layers together some distance from this fold line. Thus a pocket or tube is formed between the fold line 31 and the stitching 35. A suitable opening may be formed in the base of the bag and a liner can be inserted into the bag and secured to the top section thereof in a manner similar to that described for Figures 1 and 2. The closing arrangement for the liner at the base of the bag may also be similar to that shown in Figures 1 and 2.A container shown in these Figures can be used in exactly the same manner as that already described, being filled through the base of the container with the container in an inverted position. After filling the container may be turned the correct way up and may be lifted by the tines of a forklift truck or by a crane hook 36 engaging the pocket or tube formed between the fold line 31 and stitching 35. It will be particularly noted that the material forming this pocket is not weakened by any cutting thereof. The lack of any such cut or opening in this material also assists in ensuring that the whole of the material is engaged by the tines or on the crane hbok.

A further embodiment of container is shown in Figures 7 and 8 of the accompanying drawings. In this embodiment the container comprises a base 40, opposed sidewalls 41 and 42 and an outer top 43 all formed from a continuous length of material, the free ends of which are secured together by a seam 44 at the base of the container. Opposed sidewalls 45 and 46 and an inner top 47 are formed from a single length of material folded to U-shape and stitched to the base and to the sidewalls 41 and 42. As in the Figures 4 and 5 embodiment a lifting loop or tunnel 48 is formed between the outer top 43 and the inner top 47 and this may be engaged by the tines 49 of a forklift truck or by the hook of a crane in order to lift the container. Both the outer top 47 and the inner top 48 are devoid of any openings so that their strength is unimpaired. A liner is provided in the container in a manner similar to that shown in Figures 1 and 2, the arrangement at the base of the container again being similar to that shown in those Figures. Once again therefore the container is inverted for filling purposes, while handling during transport, storage and discharge takes place in the normal upright position of the container.

It will be understood that containers according to the invention can take forms other than those specifically shown in the drawings. The filling and discharge arrangement at the base of the container may vary from those illustrated. In some case it is not necessary for an inner liner to be provided and in these embodiments material is filled into the inverted container through a hole in the base which is then closed in any convenient manner for transport and storage and is re-opened when the container is to be emptied.

Claims

1. A flexible bulk container of woven fabric comprising a base, sidewalls and a top, and means at the top of the container by way of which the container may be lifted; the base of the container having an opening through which the container may be filled with the container in an inverted position and emptied with the container in its normal position, means being provided for closing the opening, and the top of the container being completely closed and devoid of any filling opening.

2. A flexible bulk container according to claim 1 and including an inner liner of impervious material arranged within the container for receiving the material to be carried, the liner being closed at the top thereof and having an opening associated with the opening in the base of the container through which the liner may be filled and emptied, means being provided for closing the opening in the liner.

3. A flexible bulk container according to claim 2 and including means securing the top of the liner to the top of the container.

4. A flexible bulk container according to claim 2 or claim 3 in which the liner is a length of tubular material having a top tubular section tied off and secured to the container top, the filling and emptying opening being an open-ended tubular section at the bottom of the liner extending through a hole in the base of the container and capable of being closed as required.

5. A flexible bulk container according to claim 4 in which the container includes means at the base thereof for protecting the closed tubular end of the liner.

6. A flexible bulk container substantially as herein described with reference to Figures 1 to 3 or Figures 4 to 6 or to Figures 7 and 8 of the accompanying drawings.