WO1996034811A1

WO1996034811A1 - A container

Info

Publication number: WO1996034811A1
Application number: PCT/GB1996/001047
Authority: WO
Inventors: Ivan Semenenko
Original assignee: Matcon Limited
Priority date: 1995-05-02
Filing date: 1996-05-01
Publication date: 1996-11-07
Also published as: AU5507596A

Abstract

The invention relates to a material handling system, comprising a container (20) for flowable material, comprising at least an electrically conductive surface contactable by the material, and a base therefor, the arrangement being such that the container seals an outlet (6) for material from the base (4), whereby the base (4) is protected from contamination and the system is protected from arcing.

Description

A CONTAINER

The invention relates to containers, particularly to containers which are used for storage, transport, transfer and generally handling flowable material, particularly paniculate material such as pellets, particles, powders and the like.

All these materials can prove hazardous because they are either intrinsically dust¬ like, or produce dust during flow etc. , owing to attrition and general breaking down. Such dust becomes suspended in atmosphere and the danger then arises that sparking and hence explosions can occur. This not only ruins the material, but is expensive in destroying plant and equipment, which has to be replaced, but is dangerous as it can lead to injury or even death of personnel working in a plant handling the material, which is usually handled in containers, silo's, I.B.C.s (intermediate bulk containers) and the like.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to the invention there is provided a material handling system comprising a container for flowable material, comprising at least an electrically conductive surface contactable by the material, and a base therefor, the arrangement being such that the container seals an outlet for material from the base whereby the base is protected from contamination and the system is protected from arcing.

Thus using the invention it is possible to provide a material handling system having a container which discharges electrical charge building up in the container, so obviating the danger of a spark discharge which could lead to an explosion. The surface may be an integral part of the container, or alternatively the surface may comprise a liner for a container.

The container or liner may be flexible.

The container or liner may comprise a plastics material containing an electrically conductive medium, for example copper or other conductive metal particles dispersed throughout the plastics material. Alternatively, the container or liner may comprise a woven plastics material having conductive strands interlaced in the weave.

The conductive medium may be dispersed throughout the material of the container or liner during moulding thereof.

The container may comprise means for enabling releasable attachment to a base such as a pallet.

The means may comprise an intermediate flange.

The means may also comprise a flange adapted to be attached at a mouth of the pallet so that the mouth is shielded from contact with the flowable material during discharge.

The flange may include a double thickness wall, and may also include an extension part adapted to form a ring around the outlet of the container. The container or liner may be disposable.

A container and a system embodying same are hereinafter described by way of example, with reference to the accompanying drawings. Fig. 1 is a schematic side elevational view of a prior art container;

Fig. 2 is- a schematic side elevational view of a container for use with the invention, attached to a base;

Fig. 3 is a view of the container and base of Fig. 2 in use in a material handling system according to the invention;

Fig. 4 is an enlarged view of part 'A' of Fig. 3;

Fig. 5 is a schematic side view of an alternative form of container for use with the invention;

Fig. 6 is an enlarged view of part T of Fig. 5;

Fig. 7 is an enlarged view of part U of Fig. 6; and

Fig. 8 is a schematic end view of the lower (as viewed) part of the container of Figs. 5 to 7.

Referring to the drawings, Fig. 1 shows a plastic flexible container or bag which has a mouth or opening 2 which is secured to a rim 3 of a plastic base or pallet 4 by a band clamp 5. The base or pallet 4 has a central discharge outlet 6 normally closed by an obturating device such as a conical valve 7 in the embodiment. Material in the container is discharged by setting the pallet down on a discharge station 10 (Fig. 3) so that means such as a bellows 11 and vibrator (not shown) at the discharge station 10 is raised, to lift the cone 7 so opening an annular gap through which the material flows. The vibrator ensures that there is no bridging or "rat-holing" of the material. The container 1 is of plastic, and essentially terminates at 'X' i.e. at the top (as viewed) of the pallet. There is danger of sparking and. or explosion through static build-up.

A container or bag 20 of the invention, Figs. 2 to 4, obviates the danger of sparking and/or explosion because it is electrically conductive, having a "filling" of conductive medium such as copper particles so providing an electrically conductive surface which in use is in contact with the material. Alternatively, a woven plastics material having metal strands interlaced in the weave can be used. In such materials, the plastic coating applied to the weave is exposed to the material in the container by burning microscopic holes in it, which allow contact with the metal, but are not large enough to allow material particles to enter. The container 20 has means for attaching it releasably to the pallet in the form of an annular intermediate flange 21 which is releasably securable to an upper shoulder or rim 3 the pallet by a suitable means such as a draw cord, tie or the like 22. The container 20, which is flexible and made of plastic such as polyethylene has a tapered lower (as viewed) part 24 which fits in the conical outlet 6 of the pallet. The lower part 24 terminates in a flange 25 which forms part of the attachment means and which is an annular return flange which is folded back on itself to be clamped to the outside of a wall 26 defining the outlet 6. The flange 25 extends through the outlet. This is shown in Figs. 3 and 4, where on the left and side of Fig. 3 is shown the situation where the container 20 and pallet 4 is being lowered onto a discharge station 10 in a material handling system and the right hand side shows the container 20 and pallet fully lowered. In this case a throat 27 of the discharge station 10 has engaged the return flange 25, which is external to the outlet 6 of the pallet 4 and has urged it upwardly (as viewed) and folded it to be secured to the external surface of the outlet wall 26 by a lip seal 28 of the discharge outlet. An internal seal 29 grips the internal surface of the return flange during lowering, or at other times, so that the flange 25 is always secured to the outlet wall 26. It can thus be seen that the container 20 at all times completely covers all internal surfaces of the pallet 7 its own internal surface presenting an electrically conductive surface to the material being handled, so obviating sparking or explosion.

The container 20 acts as a complete liner for the pallet.

It will be understood that in the engaged position at a discharge station 10 shown in Fig. 4, the external surface of the flange 25 does not come into contact with the particulate material as it is protected by the lip seal 28.

Referring to Figs. 5 to 8, an alternative embodiment of container for use with the invention is illustrated. The container 200 is of a similar format to that of the embodiment of Figs. 2 to 4, including an intermediate flange 210, a tapered lower (as viewed) part 240, and a terminal annular return flange 250. In addition, the upper (as viewed) part of the container 200 is provided with lift straps 300. The lower (as viewed) tapered part 240 comprises a generally frusto conical inverted skirt having a double thickness wall, as shown in Fig. 7. The skirt 240 is stitched at four places which are spaced around the circumference on the inner and outer walls to prevent raised seams.

In this embodiment the annular return flange 250 comprises a first, separate, annular piece of material 251 attached to the skirt 240 by an overlapping join 310 and a second, separate annular piece of material 252, attached to the first piece 251 at the lower (as viewed) end thereof, again, by an overlapping join 311. This lower overlapping join 311 thus forms an extension ring from the flange 250 around the outlet of the container, comprising four layers of material.

As will be appreciated, the flange 250 is thus folded back on itself in a similar way to flange 25 of the embodiment of Figs. 2 to 4, to be clamped to the outside of a wall 26 defining the central discharge outlet 6 of the base or pallet 4. The join 311 provides a further barrier to dust and particles which might otherwise contaminate the outer surface of the flange 250.

The container 20 can be disposable, simply by folding or rolling it up, being careful to ensure that no material falls out through the mouth. Thus a particularly simple, inexpensive yet safe container has been described. The invention is susceptible of being modified, for example, the conductive means may be a mesh, or series of wires at the surface exposed to the particulate material.

Claims

1. A material handling system comprising a container (20, 200) for flowable material, characterised by at least an electrically conductive surface contactable by the material, and a base (4) therefor, the arrangement being such that the container seals an outlet (6) for material from the base (4) whereby the base is protected from contamination and the system is protected from arcing.

2. A system according to Claim 1, characterised in that the surface is an integral part of the container (20).

3. A system according to Claim 1, characterised in that the surface comprises a liner for the container.

4. A system according to any preceding claim, characterised in that the container or liner is flexible.

5. A system according to any preceding claim, characterised in that the container or liner comprises a plastics material including an electrically conductive medium.

6. A system according to Claim 5, characterised in that the medium comprises conductive metal particles dispersed throughout the plastics material.

7. A system according to Claim 6, characterised by the particles comprising copper.

8. A system according to Claim 5, characterised by the container or liner comprising a woven plastics material and the conductive medium comprising conductive strands interlaced in the weave.

9. A system according to any of Claims 5 to 8, characterised in that the conductive medium is dispersed throughout the material of the container or liner during moulding thereof.

10. A system according to any preceding claim, characterised in that the container includes means (21, 25) for enabling releasable attachment to a base.

11. A system according to Claim 10, characterised by means (21) including an intermediate flange.

12. A system according to Claim 10 or Claim 11, characterised in that the means (25) includes a flange adapted to be attached at a mouth of the pallet so that the mouth is shielded from contact with the flowable material during discharge.

13. A system according to Claim 12, characterised in that the flange includes a double thickness wall.

14. A system according to Claim 12, characterised in that the flange includes an extension part, adapted to form a ring around the outlet of the container.

15. A system according to any preceding claim, characterised in that the container or liner is disposable.