Flexible Intermediate Bulk Container With Means for Partly of Complete Discharge

The present invention relates to a flexible intermediate bulk container (FIBC) having a double base construction and suitable for partial or complete discharge of bulk material.

An FIBC can be emptied either by using a long handled knife to cut one or more slits in the bottom or by lowering the FIBC onto a pyramidal shaped knife. These methods will destroy the base of the container and it cannot be reused. Further, by such method the entire contents of the FIBC will be discharged in a matter of seconds. This is not always desirable because the FIBC can contain 500-1500 kilos of bulk material. Partial discharge of bulk materials can, for various reasons, be desirable.

Norwegian patent No. 138,134 describes a FIBC with a double base construction. The FIBC comprises a sidewall structure with flaps which are integral extensions of the side wall fabric. Such flaps are joined two and two at their lower edges in such way that joining lines thereof cross at one point. Thus, the integral extensions of the pairs of equally large flaps form a double overlapping base.

Partial discharge of a FIBC will a single base construction and a discharge spout is a relatively simple operation. A great disadvantage related to this method is the need for working close to the base of a hanging container when the base mouth is opened or closed.

There has been developed a piece of board, for instance made of plastic material, to be used for partial discharge of a FIBC with a double base. This piece of board has a central opening and a handle at least at one end. The board is positioned between the flaps forming the double base. When the FIBC is emptied, a cut is made through the central part of the base. The bulk material flows freely out of the container when the opening in the board is positioned in the same position as the opening in the base of the container. The discharge is stopped and regulated by pulling or pushing the board away from the opening, and thus closing and opening in the base. In addition to the disadvantage of the necessity of working close to the base of a hanging container, this method also involves the disadvantage that the base is destroyed and the container is not reusable. A further disadvantage is that when the cut is performed some fabric from the base will pollute the bulk material. Also, the board has to be supplied separately to users, it cannot be an integral part of every container.

An object of the present invention is to provide a flexible bulk container with a double base and which can be emptied partly or completely without destroying the container base fabric and which is safe is use. Another object is to avoid polluting the bulk material with fabric of the container.

The inventors began the development of the invention by a close examination of the present methods for partial discharge of container. A further development of the discharge spout was not regarded to be convenient. The use of a board was more interesting. The inventors made permanent openings in the base of a container and then tried to find solutions to regulate or close the opening of the container. After having tested various types of boards, a board made of flexible material and fastened to the base was found to be the most appropriate. By fastening a piece of woven material to one end of the base and folding it double in between the double base structure, there is formed a closure that will cover the permanent opening in the base. The bulk material can pass through the opening in the base by pulling out that part of the closure not fastened to the base. The opening can be closed or partly closed by pushing the closure back toward its original position. This can be done by using a board positioned between the double base and between the layers of the closure.

The invention will be described in more detail by way of example only, with reference to the drawings, wherein:

FIG. 1 is a perspective view illustrating an FIBC with a double base structure and a flexible sheet closure; and

FIG. 2 is a perspective view illustrating in more detail the sheet closure seen in FIG. 1.

FIG. 1 illustrates an FIBC 1 including lifting loops 2 which preferably are integral extensions of side wall structure of the container. The lifting loop(s) can be supplied with a permanent lifting handle 3 such as a sleeve. The FIBC 1 has a double base comprising two bottom layers 4 which can be direct extensions of the side wall structure. In the center of each of the bottom layers 4 is provided an opening 5. The edges around the openings 5 can be reinforced, for instance by seams, to avoid separation of fibers. The two openings 5 are arranged directly above each other, thus forming a continuous opening in the base of the container.

Along the edges of the base are sewn seams 6, each with a length approximately equal to the length of a projection 8 at the respective side of a flexible closure 7 (FIG. 2) formed of a flexible material and of a double layer or folded structure positioned between the two base sections 4. FIG. 2 illustrates in detail closure 7 of a flexible material, for instance woven fabric of the same type as the fabric used for the FIBC. The illustrated closure 7 is doubled and at one end of one layer are provided the two projections 8 for fixedly fastening the closure 7 to the base of the FIBC 1 by the seams 6. At the other end of the other layer of the closure 7 is a handle 9 which can have various shapes. FIG. 2 illustrates one example where the handle is a rod fastened to the closure 7.

When the FIBC is to be emptied of bulk material, it is lifted by a hook and the closure 7 is in the position as shown in FIG. 1 closing the openings 5. One person can very easily empty the container partly or completely by using the handle 9 to pull out the closure 7 (to the right in FIG. 1) such that a folded edge 7a between the two layers of closure 7 progressively moves across and unblocks openings 5. The bulk material will flow freely from the openings 5. The discharge can be stopped by pushing the closure 7 back to its original position. This is easily performed by pushing a board, etc., shown schematically at 10 in FIG. 2, back in between the double layered closure.

The invention provides a simple solution of how to obtain a double based FIBC which can be used several times. The container can be completely or partially discharged in a safe manner, because opening and closing of the discharge opening can be achieved without having to work below the FIBC. The FIBC is not destroyed during discharge, and it has means for partial or complete discharge that is an integral part of the container. It also is possible to avoid pollution of bulk material with fibers of the base of the FIBC.