GB2094259A

GB2094259A - Plastics containers for pressurised liquids

Info

Publication number: GB2094259A
Application number: GB8206810A
Authority: GB
Original assignee: SAN BEDEDETTO ACQUA MINERALE
Current assignee: SAN BEDEDETTO ACQUA MINERALE
Priority date: 1981-03-10
Filing date: 1982-03-09
Publication date: 1982-09-15
Also published as: FR2501633A1; IT8120258A0; ES264128U; BE892443A; IT1139009B; FR2501633B3; ES264128Y; DE3208156A1; NL8200998A

Abstract

A plastics container comprises a cylindrical body 1 closed at the top, and an inverted truncated cone portion 3 extending between the body 1 and an annular rest surface 4, a domed cap 6 being provided within the surface 4 and having its concavity facing downwards such that tangent lines a, b led through the connection points 7, 8 of the caps 6 and the the surface 4 extend parallel to the container centreline c. The container is a bottle or can. <IMAGE>

Description

SPECIFICATION Plastics containers for pressurised liquids This invention relates to a plastics container structure intended for containing mineral water and soda drinks, or more generally pressurised liquids.

Known already are plastics materials of a particular composition which is suitable for contacting food products, such plastics being used in the construction of containers for liquid food articles.

However, where the liquids to be contained are under pressure, a significant mechanical problem arises as regards the containment of the container stresses and deforming loads.

On the other hand, the use of plastics is convenient from the economical standpoint only if the container can be constructed with very thin walls, that is from a small amount of material compared to a similar container made of glass.

This invention sets out to provide a plastics container structure for pressurised liquids, which can withstand pressure from within without breaking or deforming.

Within the above general aim, it can be arranged that this container structure is capable of withstanding mechanical stresses in spite of its comprising thin walls of plastics.

It can be further arranged that the plastics container structure of this invention can be constructed using techniques and materials which are well known to those skilled in the art.

According to one aspect of the present invention, these and other objects, such as will be apparent further on, are achieved by a plastics container structure for soda drinks or pressurised liquids, comprising a cylindrical body closed at the top in a conventional manner for bottles or cans, the bottom of said container being connected to said cylindrical body through downwardly tapering portion which defines an annulus-like rest surface at the bottom, the area defined by said annular surface being closed by a vaulted surface having its concavity facing downwards and a shape such that the geometric tangent lines led through the points of connection thereof to the annular surface lay parallel to the centreline of said container.

Further features and advantages of this invention will be more apparent from the following description of two preferred embodiments thereof, given here by way of illustration with reference to the accompanying drawings, where: Figure 1 is a phantom view of one container type, specifically a bottle; and Figure 2 is a further phantom view of a second type of container, specifically a can.

With reference to the cited drawings, the bottle shown in Fig. 1 comprises a cylindrical sidewall 1, which is completed at its lower portion with a bottom, generally indicated at 2, extending into a tapering area in the shape of a substantially inverted truncated cone, indicated at 3.

Thus, there is created a narrow rest annulus 4 having a radius equal approximately to one half the bottle maximum radius.

The circular area 5 included within said annulus 4 is closed by a domed cap 6 having its concavity facing downwards.

As is clearly shown in Fig. 1, said domed cap 6 is substantially a half ellipsoid of rotation, in which geometric tangent lines a and b led through the points 7 and 8 of contact with the annulus 4 are parallel to the bottle centreline c.

The bottom 102 of the can of Fig. 2 is quite similar, it including the inverted truncated cone connection 103 interconnecting the cylindrical portion 101 with the rest annulus 104.

Also provided is a domed cap 106 having the same configuration.

With that structure, internal pressure forces which might cause the container to break are suitably taken up. In particular, the most critical area, corresponding in section to the points 7 and 8 of Fig. 1, has a geometry such that the forces lay ona plane 9 (109 for the can embodiment) extending normal to the symmetry axis, thus allowing a distribution of loads which can be taken up by the domed cap and circular area.

Thus, the structure is made extremely strong and indeformable, at least at the pressures developed by mineral water, beer, or soda drinks.

Containers possessed of such features may be constructed with injection and blowing processes affording high output rates.

Conveniently, the material employed would be polyethylene terephtalate, which lends itself well both to the type of processing envisaged and to the use in conjunction with food products.

However, a different material may be used, and the dimensions may be any selected ones.

1. A plastics container structure for soda drinks or pressurised liquids, comprising a cylindrical body closed at the top in a conventional manner for bottles or cans, the bottom of said container being connected to said cylindrical body through a downwardly tapering cone portion which defines an annulus-like rest surface at the bottom, the area defined by said annular surface being closed by a vaulted surface having its concavity facing downwards and a shape such that the geometric tangent lines led through the points of connection thereof to the annular surface lay parallel to the centreline of said container.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Plastics containers for pressurised liquids This invention relates to a plastics container structure intended for containing mineral water and soda drinks, or more generally pressurised liquids. Known already are plastics materials of a particular composition which is suitable for contacting food products, such plastics being used in the construction of containers for liquid food articles. However, where the liquids to be contained are under pressure, a significant mechanical problem arises as regards the containment of the container stresses and deforming loads. On the other hand, the use of plastics is convenient from the economical standpoint only if the container can be constructed with very thin walls, that is from a small amount of material compared to a similar container made of glass. This invention sets out to provide a plastics container structure for pressurised liquids, which can withstand pressure from within without breaking or deforming. Within the above general aim, it can be arranged that this container structure is capable of withstanding mechanical stresses in spite of its comprising thin walls of plastics. It can be further arranged that the plastics container structure of this invention can be constructed using techniques and materials which are well known to those skilled in the art. According to one aspect of the present invention, these and other objects, such as will be apparent further on, are achieved by a plastics container structure for soda drinks or pressurised liquids, comprising a cylindrical body closed at the top in a conventional manner for bottles or cans, the bottom of said container being connected to said cylindrical body through downwardly tapering portion which defines an annulus-like rest surface at the bottom, the area defined by said annular surface being closed by a vaulted surface having its concavity facing downwards and a shape such that the geometric tangent lines led through the points of connection thereof to the annular surface lay parallel to the centreline of said container. Further features and advantages of this invention will be more apparent from the following description of two preferred embodiments thereof, given here by way of illustration with reference to the accompanying drawings, where: Figure 1 is a phantom view of one container type, specifically a bottle; and Figure 2 is a further phantom view of a second type of container, specifically a can. With reference to the cited drawings, the bottle shown in Fig. 1 comprises a cylindrical sidewall 1, which is completed at its lower portion with a bottom, generally indicated at 2, extending into a tapering area in the shape of a substantially inverted truncated cone, indicated at 3. Thus, there is created a narrow rest annulus 4 having a radius equal approximately to one half the bottle maximum radius. The circular area 5 included within said annulus 4 is closed by a domed cap 6 having its concavity facing downwards. As is clearly shown in Fig. 1, said domed cap 6 is substantially a half ellipsoid of rotation, in which geometric tangent lines a and b led through the points 7 and 8 of contact with the annulus 4 are parallel to the bottle centreline c. The bottom 102 of the can of Fig. 2 is quite similar, it including the inverted truncated cone connection 103 interconnecting the cylindrical portion 101 with the rest annulus 104. Also provided is a domed cap 106 having the same configuration. With that structure, internal pressure forces which might cause the container to break are suitably taken up. In particular, the most critical area, corresponding in section to the points 7 and 8 of Fig. 1, has a geometry such that the forces lay ona plane 9 (109 for the can embodiment) extending normal to the symmetry axis, thus allowing a distribution of loads which can be taken up by the domed cap and circular area. Thus, the structure is made extremely strong and indeformable, at least at the pressures developed by mineral water, beer, or soda drinks. Containers possessed of such features may be constructed with injection and blowing processes affording high output rates. Conveniently, the material employed would be polyethylene terephtalate, which lends itself well both to the type of processing envisaged and to the use in conjunction with food products. However, a different material may be used, and the dimensions may be any selected ones. CLAIMS

2. A container structure, characterised in that the diameter reduction in said annulus is approximately one half the actual maximum diameter of the container.

3. A container structure according to one or more of the preceding claims, characterised in that said domed cap included within said annulus has substantially the shape of an ellipsoid of rotation.

4. A container structure according to one or more of the preceding claims, characterised in that the geometric tangent lines led through the points of contact with said annulus extend parallel to the bottle centreline.

5. A container structure according to one or more of the preceding claims, characterised in that the bottom and said domed cap are a single-piece construction formed from injected, blown, or extruded plastic materials.

6. A plastics container structure for soda drinks or pressurised liquids, as herein described and illustrated.