Containers For Liquids

Abstract

A container for liquids having a substantially cylindrical stainless steel hollow body and a protective chime of rigid or semi-rigid resilient plastics material at at least one end of the body, characterised in that the body has a rib adjacent the said one end of the body, the chime extends over the rib and to lock the chime to the body a portion of the chime has been deformed behind the rib by a hot moulding process.

Description

The invention relates to containers for liquids, and in particular to containers having one or more protective chimes (e.g. beer kegs).

It is known to provide metal containers with chimes of plastics material but a problem has always been met in the attachment of a chime to the body. Usually the chimes have been attached by adhesive but this provides all sorts of difficulties particularly if the container has to be subjected to high temperatures (e.g. 140.degree.C for sterilisation).

The mechanical locking may be supplemented by an adhesive interconnection between the body and the or each chime.

The proof stress of the stainless steel may be within the range 20 to 90 tons/sq in and it is preferred that the proof stress of the walls of the body is greater than that of the ends of the body.

The plastics material of the or each chime may be such that each chime tends to bond itself to the stainless steel. For example polyethylene may be used and heat may be applied to facilitate the bonding.

The invention further provides a method of putting a chime of plastics material onto one end of a cylindrical stainless steel hollow body having a rib adjacent the one end which method is characterised by placing the chime over the one end of the body and the rib, heating the chime in the area of the rib and forming the chime behind the rib to lock the chime to the body.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings in which:

FIG. 1 is a section through a chime before it is attached to the body part;

FIG. 2 is a plan view of the chime; and

FIG. 3 is a section through the assembled keg.

The keg according to the invention comprises a substantially cylindrical hollow body 10 having a protective plastics chime 11 at each end.

The body 10 comprises upper and lower dish shaped end pressings 12 of 18 SWG stainless steel (JS 19) and a cylindrical centre section 13 of 18 SWG stainless steel (JS 19A). These parts are welded together. The upper end pressing 12 carries the keg neck 14 and the centre section 13 has two circumferential ribs 15.

Each chime 11 comprises an annular channel shaped member of Shell Carlona 50/004 F polyethylene having an internal wall 16 and an external wall 17. This particular polyethylene is dimensionally stable between -10.degree.C and 140.degree.C, has a density of about 0.95, a melt flow index of between 0.3 and 0.5 and a narrow molecular weight distribution band. Wall 16 has a foot 18 which abuts pressing 12 and wall 17 surrounds member 13. Wall 16 is formed with carrier handles 19.

Drain holes 20 are provided for removal of any liquid which gets between the chimes and the body (e.g. rainwater). Furthermore the chimes have slots 21 therethrough to prevent fluid being trapped on the keg by the chime walls. The slots 21 are defined by walls 22 which are arranged oblique to the radial direction to permit slight flexing. If the slots 21 and hence walls 22 were purely radial the chime would be too stiff in the region of slots 21 and might fracture in use (e.g. if the keg is dropped) or transmit to the steel body an undesirably high proportion of any blow received by the chime during use.

Each chime is initially formed (by injection moulding) as shown in FIGS. 1 and 2, the free end of wall 17 being cylindrical. The chime is attached to the keg by sliding it onto an end of the keg until the free end of wall 17 extends past one of the ribs 15 and foot 18 abuts one of the end pressings with the axis of the keg and the pressing extending vertically. The chime is retained in this position by an axial load. A curtain of hot air is directed on to the free end of the wall 17 of the chime at an angle of 45.degree. with the axis so that the end divides the air stream to flow both outside the chime and between the chime and the keg. Thus both the inside and outside surfaces of the chime are heated. An air cooled shoe or skid is brought into contact with the part of the chime to be deformed and relative rotation takes place between the shoe and the chime about the said axis. The heating of the chime is continued until there is no apparent elasticity remaining in the material of the chime i.e., the deformed portion remains deformed. Cold air is then substituted for the hot air and the shoe is kept in contact with the chime until the material is sufficiently cool for no further deformation to take place.

If desired the shoe could be replaced by a circular die divided into a number of segments (rather like a collet chuck). In this case rotation between the chime and the die need not be necessary.

Some adhesion between the steel and polyethylene may also occur. This may be supplemented by the use of adhesive.

The invention is not restricted to the features of the foregoing example. For instance the foot 18 of each chime may be extended radially inwardly to provide a disc or ring covering the end pressings 12.

Claims

We claim:

1. A container for liquids having a substantially cylindrical stainless steel hollow body and a protective chime of rigid or semi-rigid resilient plastics material at at least one end of the body, characterised in that the body has a rib adjacent the said one end of the body, the chime extends over the rib and to lock the chime to the body a portion of the chime has been deformed behind the rib by a hot moulding process.

2. A container as claimed in claim 1 in which there is a rib at each end of the body.

3. A container as claimed in claim 1 in which the stainless steel has a proof strip within the range of 20 to 90 tons/sq in.

4. A container as claimed in claim 1 in which the plastics material is also bonded to the stainless steel.