The present invention relates to improvements in packaging for liquid and granular goods , and particularly for dangerous goods.

In the past , the transportation , storage and disposal of used containers has been a problem , particularly in the chemical industry . The inside surfaces of an empty container are invariably coated with a residue of the material stored in it and in the case of dangerous goods , the empty container is often also potentially hazardous . The usual methods of container disposal such as dumping , burning or pulverising do not effectively eliminate this hazard , and often act to concentrate or release the hazardous residue .

Empty containers have also been expensive to transport because of their relatively high volume to weight ratio .

The invention thereby enables efficient reuse of containers , and their economical packing for return to the contents manufacturer or packer , or to a container recycling station for cleaning , detoxification and reuse . Naturally , non-dangerous goods may also be stored in these containers .

It is therefore an object of the invention to provide an improved storage container which overcomes or substantially ameliorates at least some of the deficiencies of the prior art .

Accordingly , the invention provides a stackable and nestable container comprising a substantially hollow tapered container shell , handle means and a pouring means disposed on or adjacent the narrower top end of the shell , a removable container base releasably engageable with the wider bottom end of the shells and a clamping means adapted releasably to lock the shell and the base together .

In one preferred form of the invention , the shell and the base are releasably connected by complementary screw and thread portions . In other forms , the invention requires no threads between the container shell and the container base . In such cases , the seal may , for example comprise a clamp and a suitable gasket . In another form of the invention , two gaskets are provided, one at the outside of the thread and one at the inside of the thread , for a double seal as shown in Fig. 13.

Another preferred form of this invention incorporates a second thread and captive gasket in the bottom of the container base . This enables one container base to screw into another container base for a hermetic seal as shown in Fig. 14.

The components of the container may be made of any combination of suitable materials such as moulded plastic or metal , depending on container size and the required chemical resistance . The gaskets may be made of any suitable material such as neoprene , rubber or any other compatible material which possesses the necessary resiliance and chemical resistance properties .

To assist with understanding the invention , a preferred embodiment of the invention will now be described , by way of example only , with reference to the accompanying drawings in which :-

Fig. 1 shows one example of a container according to this invention;

Fig. 2 shows an exploded view of the container of figure 1;

Fig. 3 shows a vertical section through the container; Pig. 4 shows ci side view of the container; Fig. 5 shows the top view of the container;

Fig. S shows the bottom view of the container;

Fig. 7 shows the top view of the base of the container;

Fig. 8 shows the principle of vertical stacking of assembled containers , whether full or empty; Fig. 9 shows an example of the method of connection between the tapered drum shell and the base of the container;

Fig. 10 shows the method of connection between two nested tapered container shells; Fig. 11 shows the principle of vertical nesting of disassembled container components according to this invention;

Fig. 12 shows an example of vertical nesting of disassembled container components incorporating base elements which connect together;

Fig. 13 shows an example of the connection between the tapered container shell and the container base incorporating a double gasket seal;

Fig. 14 shows an example of the method of connection between two container base elements;

Fig. 15 shows the principle of packing disassembled container base elements into a separate sealed container;

Refering firstly to Fig. 2 of the drawings it can be seen that the stackable container according to this invention comprises a nollow tapered container shell (1) , in the shape of a truncated cone with a handle (2) and a pouring cap (3) on the top , a removable circular container base (4) and a lever clamp (5) which locks the shell and the base together .

The container shell is tapered in a frusto-conical fashion to permit close nesting of one container shell into the other . The angle of the conical taper is such that it permits full but loose nesting of a plurality of like shells , having regard to the relevant shell wall material thickness . The inside angle of the conical taper will vary with the thickness of the container shell wall .

Two integral projecting rings (6) and .7) at the base of the conical container shell prevent the nested shells from jamming together , afford additional stiffness to the lower container rim , and provide a grip for the circumferential lever clamp (5) , when the container shells are nested . The lower projecting ring (7) has a number of notches (8) for gripping the container shell during assembly and disassembly of the container .

The handle (2) is attached to the container shell with a pinned connection to enable the handle to fold flat for stacking and nesting of the containers and their components . The pouring cap (3) is also recessed below the top plane of the container shell to improve the stability of the container stack .

The container base (4) is indented so as to match the shape of the top of the container shell when two or more containers are stacked vertically as shown in Fig. 8.

The container base incorporates two keyways (9) which are used for gripping the base during assembly and disassembly of the container . The base also has a pattern of radial corrugations (10) for rigidity . The inside corner of the container base is rounded for ease of cleaning and reinforced with radial ribs (11) to enhance the rigidity of the clamped joint between the container shell and the container base.

The seal between container shell and base is accomplished by means of complementary interengageable screw threads formed on the respective elements and a captive gasket (13) disposed therebetween . A circumferential lever clamp (5) is also used to apply additional pressure on the gasket seal and prevent the separation of the threaded connection.

An integral vertically projecting ring (14) on the container base provides additional lateral stiffness at the clamped joint.

In the nested configuration, as shown in Fig. 10 , the outer of a pair of nesting container shells seals with its captive gasket (13) against the projecting ring (6) on the outside surface of the inner container shell thus confining the contents residue within the nested shells . In this nested configuration , the container shells are clamped with the same lever clamps (5) , as used to lock shells and bases together on assembled containers.

In the case of dangerous contents or contents which necessitate specialised treatment of used containers , the bases of disassembled containers can be packed into a separate sealed container , of a similar type but larger size , for transport to a recycling station as shown in Fig. 15 .

Although the invention has been described with reference to specific examples , it will be appreciated by those skilled in the art that the invention may be embodied in many other forms .