GB2029798A

GB2029798A - Containers

Info

Publication number: GB2029798A
Application number: GB7904298A
Authority: GB
Original assignee: Tioxide Group Ltd
Current assignee: Tioxide Group Ltd
Priority date: 1978-09-16
Filing date: 1979-02-07
Publication date: 1980-03-26
Also published as: GB2029798B

Abstract

A flexible container having a filler tube 4 in the cover 3 and a discharge tube 6 in the base and a number of flaps 8 attached to the base by one side, the free sides of which are releasably fixed over the discharge tube has rings 13, 14 suspended from the wall or base of the container to surround the discharge tube, when extended, so that when one ring is turned relative to the other the interior cross-section of the discharge tube is restricted thereby controlling the rate of discharge of material from the container through the discharge tube. <IMAGE>

Description

SPECIFICATION Containers The present invention relates to an improved container for the transport and delivery of finelydivided solids, for example of pigmentary titanium dioxide.

It has hitherto been common practice to pack, transport and deliver finely-divided solids such as pigmentary titanium dioxide in separate sealed bags, normally of multi-ply paper, which contain a convenient weight of product for handling by the operator, for example of 25 kilograms. Transport and delivery of quantities of solid in excess of the weight of one bag are normally undertaken by stacking the appropriate number of bags on a wooden pallette. Such loaded pallettes are conveniently moved by mechanical handling equipment such as by a fork lift truck.

However, the use of relatively small sacks in inconvenient in that the user has to open each sack prior to the discharge of its contents with the consequent utilisation of time and effort.

Furthermore, excessive handling may cause dust problems. Also, the disposal of a large number of emptied bags (which may contain some residual powder) and of the wooden pallettes (which normally require storage prior to their return to the manufacturer) also presents some difficulties.

Where the pallettes are not returned, as frequently happens, the supply of replacement pallettes is a substantial cost to the manufacturer.

The foregoing difficulties in the packing, transport and discharge of finely-divided solids has caused the manufacturers of such solids to use alternative forms of containers which contain a substantially greater amount of solid and which are designed for mechanical handling and discharge. These containers normally comprise a flexible cylindrical upper portion and a flexible lower portion formed as an invented truncated cone terminating in a base outlet. In use, the outlet is closed and is collapsed on a flat surface during the filling and transport of the container.

During discharge the container is lifted so that the truncated cone is extended by the weight of the contained solid and the base outlet is then opened to allow the solid to be discharged.

Such containers suffer certain disadvantages, particularly in the handling of material such as titanium dioxide, in that the containers must normally be retained on a flat surface during filling and transport in order to support the lower half of the container and this part of the container is not normally adequately protected during filling and/or transport nor is the angle taken up by the lower half of the container during discharge adequately supported. Furthermore, such containers have no means whereby the rate of discharge may be controlled.Both these features are of considerable importance, particularly in the discharge of material such as titanium dioxide, where the angle of the base of the container during discharge is important in determining the efficiency of discharge and the control of the rate of discharge enables the contents to be discharged directly in to the vessel in which the contents are to be used, for example into a mixing vessel.

One type of container which overcomes many of these difficulties is described and claimed in U.K. Patent Application 07192/78.

It is an object of the present invention to provide an improved container for finely-divided solids.

Accordingly, the present invention is a container comprising a surrounding wall, a cover and a base; both wall, base and cover being of flexible material, the base and cover being provided with flexible tubes having releasable closure means, a plurality of flaps attached externally to the base by one side and the free sides of which are provided with releasable connecting means whereby the flaps can be secured over the flexible discharge tube, means for suspending rings from the wall or base in such a manner as to surround the discharge tube, when extended, one above the other and the rings being interconnected by flexible suspending means whereby rotation of a ring relative to the other reduces the internal cross-section of the discharge tube and means for lifting the container.

The surrounding wall, which is preferably cylindrical when the container is full, the base and cover are normally made from the same material and may be secured to each other by conventional means, for example by sewing the periphery of the base and cover to opposite edges of the surrounding wall of the container. It is, however, preferred to form at least part of the surrounding wall and base of a single piece of material, thereby eliminating the horizontal seam between the surrounding wall and base.

One very suitable material, both from the point of view of strength and cost, is a woven cloth of polypropylene filaments, the filaments being coated with a mixture of polypropylene and polyethylene. The cloth is suitably woven to prevent leaking of the contents and of suitable filament thickness, for example of about 1000 denier, to provide the necessary strength.

It has also been found that such a material resists staining; has excellent retaining properties for pigment TiO2 and does not show too great an affinity for the contents during emptying.

Materials such as polyvinyl chloride-covered polyester filaments and/or rubber covered nylon fabric have been found to be more expensive and are not preferred.

The base of the container is preferably attached to the lower edge of the wall of the container in such a manner and is so constructed that when the contents are being discharged, the base assumes an angle of between 550 and 750 and preferably an angle between 600 and 700, with a horizontal plane across the base of the surrounding wall of the container. It has been found that such an angle is particularly suitable in assisting the discharge, for example, of pigmentary titanium dioxide from the container via the discharge tube.

The flexible tubes in the base and cover are, respectively, discharge and filing tubes for the container and are normally of the same type of material as the container but woven from smaller diameter filaments to give greater flexibility. Both tubes are normally provided with tie-cords as the releasable closure means.

It may be desirable to provide in the cover, in addition to the flexible filling tube, a second tube which is adapted to be connected to a dustremoving means.

The flaps on the base are conveniently releasably interconnected by doubling over and sewing a portion of the free side of the flaps to form a passage-way for a draw-string which, when tightened and tied, retains the flaps in position against the base thereby protecting the discharge tube from damage during handling and/or during transport. When released it is preferred that the flaps, which are conveniently four in number and quadrant in shape, form a cone-like structure which assists in supporting the base to some extent and in directing the discharge of the material, for example pigmentary titanium dioxide.It has been found to be of advantage to reinforce the flaps, for example by the use of a material such as polyvinylchloride fabric to increase resistance to wear and to assist in supporting the base of the container at the desired angle during the discharge of the contents of the container.

Such flaps also improve the stability of the container, for example when standing on a flat surface, since a flatter base is provided when the flaps are secured in position over the discharge tube.

Another advantage is that on release of the flaps mass flow of the finely-divided solid is established and it has been found that even compacted material flows satisfactorily due to the movement of the base of the container on release of the flaps.

The provision of flaps, when secured, also reduces the amount of head room required when the containers are being manoeuvred since the base and discharge tube are contained within the flatter lower surface formed by the flaps.

In order to control the rate of discharge two rings of difficulty deformable material, for example of mild steel or a hard polymer, are suspended from the wall or base of the container in such a manner that the rings surround the discharge tube when the latter is extended.

Conveniently, the rings may be releasably suspended from loops or the like attached to the wall or base of the container by flexible cords, for example of plaited nylon or or polypropylene filaments. The rings are suspended in such a manner that one is suspended above the other and conveniently about the mid-point of the outside of the discharge tube. Normally, the lower ring is separated from, and interconnected to, the upper ring by flexible cords of similar type to that used for suspending the upper ring from the wall or base of the container. Normally, four cords (and loops for their attachment to the container) are provided but this number may be varied as desired. The rings are separated from each other by a sufficient distance to allow a ring to be rotated with respect to the other in such a manner as to reduce the internal cross-section of the discharge tube.One or both the rings may be produced with an externally-directed handle to facilitate rotation of the ring(s).

Restriction of the internal cross-section of the discharge tube (and consequent limitation of the ,rate of discharge) may be brought about by ,pressure of the cords on the discharge tube as the ring(s) is rotated in a horizontal plane.

Preferably, the rings are releasably connected to the wall or base of the container so that they can be removed and re-used on other containers.

However, even if the rings of the present invention are permanently fixed to the container, the resulting container is cheaper than one having rings sewn into the wall of the discharge tube since the sewing operation in the iatter case increases the cost of the containers.

One embodiment of the present invention comprises a container the side, base and cover of which are woven from 1000 denier polypropylene filaments coated with a mixed polypropylene (80%) polyethylene (20%) composition.

The container is, when extended, approximately 40" in diameter, 45" in depth (from cover to base) and is provided with flexible filling and discharge tubes 18" in diameter at the centres of the cover and base. These tubes are made of woven polypropylene cloth similar to that of the remainder of the container but of smaller diameter filaments to give them increased flexibility. Cords are provided to tie off the tubes when the container is full.

Equidistantly around the periphery of the base of the container are sewn the base sides of four flaps of quadrant shape, the apexes of which are doubled over and sewn to form a passage for a draw-string which, when tightened and tied, retains the flaps firmly in position against the base and which protect the discharge tube. When released and during discharge the base forms an angle approximately 650 with a horizontal plane across the base of the surrounding wall of the container and is supported to some extent in this position by the presence of the flaps.

To the outside of the surrounding wall of the container are sewn four looped handles whereby the container can be lifted, for example by means of a fork lift truck.

Two mild steel rings 3/8" in diameter are suspended by means of four cords of plaited polypropylene filaments from loops sewn on the base of the wall of the container and hanging respectively 30" and 42" below the lower edge of the wall of the container and surrounding the discharge tube, when extended, at a distance of 12" and 24" below the junction of the discharge tube and the base of the container.

The drawing accompanying this Specification shows one embodiment of the invention similar to that described above wherein there is shown a surrounding wall (1) fixed to base (2) and cover (3). The cover is provided with a flexible filling tube (4) and a tie cord (5) and the base is also provided with discharge tube (6) and tie cord (7).

Four flaps (8) of quadrant shape are provided and interconnected by draw string (9). Lifting handles (10) are also shown. To loops (1 1 ) of which only three of the four are shown are tied cords (12) which suspend rings (1 3) and (14) to encircle discharge tube (6). Ring (14) is provided with handles (1 5) to facilitate its rotation with respect to ring (13).

In use the full container is suspended above the receiving vessel, the drawn string on the flaps is then released and the discharge tube extended.

The rings are suspended in such a manner as to encircle the discharge tube, the tie string on the discharge tube released and the rate of discharge is controlled by rotating the rings with respect to each other.

Claims

1. A container comprising a surrounding wall, a cover and a base; both wall, base and cover being of flexible material, the base and cover being provided with flexible tubes having releasable closure means, a plurality of flaps attached externally to the base by one side and the free sides of which are provided with releasable connecting means whereby the flaps can be secured over the flexible discharge tube, means for suspending rings from the wall or base in such a manner as to surround the discharge tube, when extended, one above the other and the rings being interconnected by flexible suspending means whereby rotation of a ring relative to the other reduces the internal cross-section of the discharge tube and means for lifting the container.

2. A container as claimed in claim 1 wherein the container is so manufactured that there is no horizontal seam between surrounding wall and base.

3. A container as claimed in claim 1 or 2 wherein the flaps contain reinforcing material.

4. A container as claimed in claim 3 wherein the presence of the reinforcing material assists in supporting the base of the container at an angle in the range 55 to 750 with a horizontal plane across the base of the surrounding wall of the container.

5. A container as claimed in claim 4 wherein the base of the container is supported at an angle in the range 60 to 700.

6. A container as claimed in any one of the preceding claims wherein the rings are releasably suspended from the wall or base of the container.

7. A container as claimed in any one of the preceding claims wherein at least one ring is provided with an externally-directed handle.

8. A container substantially as herein described and shown in the attached drawing.