GB2096977A

GB2096977A - Collapsible container

Info

Publication number: GB2096977A
Application number: GB8111153A
Authority: GB
Original assignee: Revent Food Machinery AB
Current assignee: Revent Food Machinery AB
Priority date: 1981-04-09
Filing date: 1981-04-09
Publication date: 1982-10-27
Also published as: GB2096977B

Abstract

A collapsible storage and transporting container for pulverous or other fluidizable material has a rigid base (11) provided with support feet (13) and a bag (12) made of pliable material and secured to the base. The base (11) comprises a rigid hopper or funnel-shaped bottom wall (16) exposed to the interior of the bag and having an outlet opening (17). A tubular discharge member (18) is adapted to be connected to a pneumatic conveying system through a pipe (19) mounted beneath the bottom wall (16). The bottom wall is provided with a pneumatic fluidizing device comprising an air-permeable fabric (25) positioned on the upper side of the bottom wall (16) and means (26) for introducing air between the fabric (25) and the bottom wall (16). With the pliable bag (12) collapsed within the base, containers can be stacked on top of each other. <IMAGE>

Description

SPECIFICATION Collapsible storage and transporting container This invention relates to a collapsible container for the storage and transport of granular or pulverous material, such as flour. More particularly, the invention relates to a container of the kind defined in the preamble of the independçent claims.

Containers of this kind are often used as shipping and dispensing packages for various types of fluidizable materials, i.e. solid maerials which can be made to behave as a liquid. Such container are used for flour, for example. The supplier fills the material into the container through the filling opening of the bag and the filled container is then shipped to the customer who withdraws the material through the outlet as and when needed. When the container is empty and the bag has been collapsed into the base, the container is returned to the supplier, preferably stacked with a plurality of similar empty containers.

A known container of the afore-mentioned kind has its bag secured around the outlet which is formed by a central opening in a rigid, flat base plate and controlled by a manually operated valve.

In the known container, the flow of material through the outlet is often interrupted because of arching of the material across the outlet and can be resumed only after the arch has been caused to collapse. In order that the container may be emptied completely, it is also necessary to lift the bag when almost empty so that the lowermost portion of the bag forms a funnel opening into the outlet. Moreover, the vessel or other recipient into which the material is discharged has to be at a lower level than the container, and accordingly it is necessary either to elevate the container from the floor or to dispose the recipient below the floor or other support on which the container rests.

The primary object of the invention is to provide a container of the afore-mentioned kind which permits discharge of the material without requiring a manual operation at the container, regardless of where and at what level the container is placed. To this end, the container of the invention is constructed as set forth in the independent claim. Preferred embodiments of the container may have one or more of the features recited in the dependent claims.

The invention will be described further by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of one embodiment of empty containers similar to that shown in Fig. 1; Fig. 2 is an elevational view of a stack formed of empty containers similar to that show in Fig. 1; Fig. 3 is an enlarged view in vertical section of the base of the container in Fig. 1.

As shown in the drawings, the container comprises a base 11 and a bag 12 made of plastic-coated air-impermeable fabric and secured to the base. Four uniformly spaced support feet 11 are provided on the base. The prongs of a fork-lift truck may be inserted through the spaces between these support feet when the container is to be lifted and transported. A support frame 14 secured to the feet 13 transfers the weight of the lifted container to the prongs.

The base 11 is circular in plan view and comprises a substantially cylindrical peripheral wall 1 5, on which the support feet 13 are integrally formed, and a hopper or funnel-shaped bottom wall 16, the upper or outer circumfererial edge of which is secured to the peripheral wall and the lowermost portion of which has a central outlet opening 1 7 and a tubular discharge member 1 8. The discharge member 18 is secured to the bottom wall around the outlet opening and communicates with one end of a discharge pipe 19 mounted between the bottom wall 1 6 and the support frame 14. The other end of the discharge pipe is adapted to be connected with a pneumatic conveying system of any suitable type (not shown) and readily accessible through the opening between two adjacent feet 13.The base 11 is rigid so that the peripheral wall 1 5 and the bottom wall 16 are not moved relative to one another or deformed by the forces resulting from normal use of the container.

At its upper end the peripheral wall 1 5 has a reduced or radially inwardly offset portion 20 which forms an attachment for the upper circumferential edge of the bottom wall 1 6 which is welded to the upper edge of the reduced portion -- and for the lower open end of the bag 12.

The bag 12 thus is not constricted at its lower end, but open to the bottom wall over the entire cross-sectional area. A circumferential clamping ring 21 clamps the lower marginal portion of the bag 12 to the outer surface of the offset portion 20.

The diameter and height of the offset portion 20 of the base 11 are such that the container when empty can be stacked with similar, empty containers as shown in Fig. 2. In the stack, the feel of the base of any overlying container rest on the base of the underlying container, viz. on the horizontal annular portion 20B joining the offset portion 20 with the body of the peripheral wall 1 5.

The horizontal portion 20B is not wide enough to permit the containers in the stack to move appreciably in the horizontal direction relative to one another.

As shown in Fig. 1 the bag 12 is generally in the shape of a circular cylinder when it is filled. A filling neck 22 which can be closed by means of a lace is provided centrally in a top wall of the bag.

Along the junction between the top wall and the generally cylindrical circumferential wall the bag 12 is provided with a number of loops 23 adapted to receive horizontal arched arms 24A of a pair of filling supports 24 releasably attached to the base 11. These supports are used during the filling to maintain the bag in a raised position but are normally removed immediately after completed filling and thus do not normally accompany the container to the customer. In any case, when empty containers are to be stacked as shown in Fig. 2 it is of course necessary to remove the SuppOrts.

A pneumatic fluidizing device provided on the bottom wall 16 includes an air-permeable sheet, viz. a fine-mesh fabric 25 overlying the upper side of the bottom wall and a plurality of hoses 26 connected to the bottom wall and serving to introduce air between the bottom wall and the fabric 25. A common air supply tube 26A feeds air to the hoses.

The fabric 25 covers the entire upper side of the bottom wall 16. Along the upper edge of the bottom wall the fabric is clamped to the offset portion 20 together with the lower marginal region of the bag 12. In the region of the outlet opening 1 7 the fabric extends into the discharge member 18 and is clamped to the inner side thereof by a clamping ring 27. A number of bars 28, two of which fern shown in Fig. 3, extend radially between the outlet opening 17 and the offset portion 20 and clamp the fabric to the bottom wall 1 6 along radial lines.

Within the sector-shaped areas between adjacent bars 28 the fabric 25 is unattached to the bottom wall 16 and thus has a certain limited freedom of movement relative to the bottom wall.

Within these areas the fabric can also admit air into the space above the fabric. Air supplied through the hoses 26-these are connected substantially centrally of the sector-shaped areas - can thus pass through the fabric, distributed over substantially the entire area thereof, and enter the granular or pulverous material in the container which is thereby fluidized so that it flows to and through the outlet opening 17 where it is entrained by the conveying air stream. The fluidizing air also causes vibratory motions of the sheet which promote the fluidization.

The apex angle a of the hopper or funnelshaped bottom wall 16 should not be substantially smaller than is required to ensure flow of the material to and through the outlet opening. In the container according to the invention this requirement is met even with a fairly large apex angle. A large apex angle is advantageous in that it results in a low total height of the base. On the other hand, the apex angle should be sufficiently small to provide for sufficient space for accommodation of the empty bag in the base so that the collapsed bag does not interfere with the stacking of the containers. An apex angle a in the region of 1200 to 1650 generally is suitable and where possible an apex angle near the upper limit of the range should be chosen.

Claims

1. Collapsible storage and transporting container for granular or pulverous material, comprising a a rigid base having spaced floor-engaging -support feet and provided with an outlet, and a bag made of flexible sheet material and secured to the base with the interior of the bag communicating with the outlet, the bag having a closable filling opening at the top thereof and being adapted when empty to be collapsed into the base, the container being adapted to be stacked with other similar containers when the bag is collapsed into the base, characterized in that the base (11) includes a rigid hopper-shaped bottom wall (16) provided with said outlet (17) at the lower central portion thereof, the lower end of the bag (12) is secured to the base along the peripheral outer edge of the bottom wall, the bottom wall (16) is provided with a pneumatic fluidizing device (25, 26) and connected at said outlet (17) to a tubular discharge member (18) adapted to be connected to a pneumatic conveying system through the space between adjacent support feet (13).

2. Container according to claim 1, characterized in that the base (11) comprises a generally cylindrical peripheral wall (15) the upper portion (20) of which is offset radially inwardly to provide a recess for receiving the support feet (13) of an overlying similar container, and in that the lower end of the bag (12) is clamped to the outer circumferential surface of the offset upper portion (20).

3. Container according to claim 1, characterized in that the pneumatic fluidizing device comprises an air-permeable flexible sheet overlying the upper side of the bottom wall (16), and air supply means (26) for supplying pressurized air between the sheet (25) and the bottom wall (16), the sheet (25) being attached to the bottom wall along a plurality of substantially radial lines (28) extending from the outlet (17) to the periphery of the bottom wall.

4. Container according to any one of claims 1 to 3, characterized in that the bottom wall (16) is frustoconical with an apex angle of 1 200 to 1 650.

5. A collapsible storage and transporting container for granular or pulverous material, substantially as described herein and illustrated in the drawing.