EP0954487B1

EP0954487B1 - Vented closures

Info

Publication number: EP0954487B1
Application number: EP97912337A
Authority: EP
Inventors: Michel Boulang; Philippe Davous
Original assignee: Koninklijke Emballage Industrie Van Leer BV
Current assignee: Greif International Holding BV
Priority date: 1996-11-19
Filing date: 1997-11-18
Publication date: 2003-02-05
Anticipated expiration: 2017-11-18
Also published as: ES2191832T3; EP0954487A1; DE69718934D1; DE69718934T2; AU4957297A; WO1998022363A1; JP2001504068A; CN1237938A; AU731992B2; BR9714638A; CN1100709C

Description

This invention relates to a method of and apparatus for providing a vented closure for a container and it particularly relates to venting members for container-closure combinations.

A known type of container-closure combination has complimentary, non-gas tight features by which the closure may be removeably attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container; such a combination is illustrated by Document CH-A-357330. Liquid containers can become over or under pressurised and the container damaged, such as by ballooning or crushing, depending on the liquid to be contained and the ambient temperatures. One solution is to make the container strong enough to resist such changes, another solution is to fit the container with a gas vent. The choice of solution is mainly an economic one, depending upon whether or not it is cheaper to make the container stronger or to fit a gas vent.

Known gas vents for container-closure combinations require special closures and/or modified containers.

Document WO-A-95/26913 discloses a cap lining for bi-directional venting from the interior of a container to the ambient atmosphere through openings existing between the spiral screw threads of the cap closure and threads of the container neck; the only seal disclosed between the cap and the container is that provided by compression of the cap lining plies.

According to the present invention, a method of converting a sealed container-closure combination to a vented container-closure combination, the combination having complimentary non-gas-tight features by which the closure may be removeaby attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container, comprises adding a venting converter to by-pass the sealing member and form a liquid-tight, gas-venting seal between the closure and the container and provide a venting gas path from the inside of the container through the venting converter to atmosphere via the complimentary closure and container features.

No modification to either the closure or the container is required when using the method of the present invention.

Also according to the present invention, in a container-closure closure combination having complimentary, none gas-tight features by which the closure may be removeably attached to the container and a sealing member to form a fluid-tight seal between the closure and container if no venting converter is applied, a venting converter is fitted as a liquid-tight, gas-venting seal between the closure and the container, the converter being shaped and configured to by-pass the sealing member of the container-closure combination; whereby, in use, a venting gas path is provided from the inside of the container through the venting member to atmosphere via the complimentary closure and container features.

Thus, a liquid container can be economically provided with a gas vent according to the present invention; no modification of the container or closure being required, simply by the provision of a suitable venting converter and taking advantage of the potential gas flow path already present between the closure and container attachment features.

In a preferred embodiment, the venting member is microporous; for example a microporous membrane.

The advantages of the using microporous membranes for vented closures is that they work at zero differential pressures and are bi-directional; i.e. they vent gases in both directions, in and out of a container. The main disadvantage of such use of microporous membranes is that their operating efficiency is severely reduced when wetted by a liquid, such that the membrane hardly works at all.

According to a further embodiment of the method and combination of the present invention, and wherein the closure is a cap having an integral sealing member and the container has a neck, the cap and neck having the complimentary features; the venting converter is an insert for the cap shaped to generally conform to the inner shape of the closure cap and sealing member; whereby the venting converter can, in use, by-pass the sealing member. Gas flow means may be provided between the insert and the cap.

According to a further embodiment of the method and combination of the present invention, and wherein the sealing member is a sealing flange depending from the cap; the insert has a corrugated rim portion with two concentric peripheral grooves respectively opening upwards, to accommodate and by-pass the cap sealing flange, and downwards, to accommodate the rim of the container neck .

The present invention also includes a venting converter for a sealed container-closure combination as claimed in claim 12.

The above and other features of the present invention are illustrated, by way of example, in the Drawings; wherein:-

Fig. 1: is a cross-sectional view of a microporous membrane vented closure for a liquid container in accordance with the present invention;
Fig.2: is an exploded cross-sectional view of the closure of Fig. 1:
Fig.3: is a cross-sectional view of a container neck;
Fig.4: is a cross-sectional view of the closure of Fig. 1 screwed onto the neck of Fig. 3;
Fig. 5: is a side elevation corresponding to Fig. 4; and,
Fig. 6: is an enlarged detail of part of Fig. 4.

As shown by the figures, a microporous membrane vented closure 10 consists of a generally circular insert 12 moulded from a suitable rigid plastics material, such as LDPE, to generally conform to the inner shape of a container cap 14. The insert 12 has a central aperture 16 with an air-side, surrounding, axially upwardly extending, cylindrical lip 18 and a radially extending liquid-side rim 20. The rim 20 has a liquid-side, surrounding, axially downwardly extending, cylindrical rib 22. The aperture 16 is closed on the liquid-side by a microporous membrane 24, for example of "GORETEX®", that is bonded, such as by welding, within the rib 22 to the rim 20 to form a liquid seal therewith.

The membrane 24 is protected on the liquid-side by a moulded plastic cup 26, having cylindrical upper part the external diameter of which is an interference, liquid-tight fit within a liquid-side, axially extending, cylindrical, outer rib 30, that co-axially surrounds rib 22.

The cup 26 has an external, radially outwardly extending flange that acts as a stop against the rim of rib 30, to control the depth of insertion of the cup upper part.

The cup 26 has a hemispherically-shaped bottom part that is provided with a central port 28; the port 28 is dimensioned so that it can act as a capillary port, using the surface tension of a liquid to be contained in the container act to prevent that liquid from normally entering the cup.

Outer rib 30 is an integral part of and depends from a dished central portion 32 of the insert 12 that flares upwardly and outwardly from lip 18 to a corrugated rim portion 34. The rim portion 34 has two concentric

peripheral grooves

36 and 38 respectively opening upwards, to accommodate an integral sealing flange 40 that depends within the container cap 14, and downwards, to accommodate the rim 42 of a container neck 44.

The air-side, cap facing surface of insert 12 is roughened and the dished central portion is provided with integral ribs 46 extending radially to the rim portion 34.

In use, and especially as shown by Figs 1, 4 and 6, the vented closure 10, comprising insert 12 with membrane 24 and cup 26 is fitted within a conventional container cap 14 and the whole assembly is screwed onto the neck 44 of a container 48.

Gases within the container 48 can vent:-

through the microporous membrane 24,

within the insert cylindrical lip 18,

though notches 50 in the rim of lip 18,

between the under-surface of cap 14 and the ribs 46 on the facing surface of insert 12,

around and between cap sealing flange 40 and the roughened, cap-facing surface of insert groove 36,

around and between the roughened, cap-facing surface of insert groove 38 and the cap 14;

down through the cap and

neck threads

52, 54; and,

past the cap anti-tamper ring 56 to atmosphere;

and as shown by the arrows in Fig. 6.

A sealing ring 58 is located between the neck rim 42 and the insert groove 38 to seal the insert with the container; as the insert, perforce, by-passes the cap's integral sealing flange 40.

This complex gas passage effectively forms a labyrinth seal on the air-side of the microporous diaphragm; thus;-

the cap protects the membrane from any contamination coming from outside during storage or transport of the container;

the same cap can be used for vented and non-vented applications, simply by insertion of a vented closure into the cap;

the membrane is welded to the insert to ensure that it remains liquid tight; and, the cap has no gas ports or perforations.

By this means, a non-vented cap-closure can readily and simply be converted to a vented closure by by-passing the existing sealing member within a conventional container cap 14 with insert 12, including membrane 24 and cup 26; provided that there is a sufficient gas leakage path between the cap and neck threads.

Claims

A method of converting a sealed container-closure combination to a vented container-closure combination, the combination having complimentary, non-gas-tight features (52,54) by which the closure (10) may be removeably attached to close the container (48) and a sealing member (40) to form a fluid-tight seal between the closure and the container; characterised by adding a venting converter (12) to by-pass the sealing member (40) and form a liquid-tight, gas-venting seal between the closure (10) and the container (48) and provide a venting gas path from the inside of the container through the venting converter past the fluid-tight seal to atmosphere via the complimentary closure and container features (52,54).
A method as claimed in claim 1, characterised in that the venting converter (12) is microporous.
A container-closure combination having complimentary, non-gas tight features (52,54) by which the closure (10) may be removeably attached to close the container (48) and a sealing member (40) to form a fluid-tight seal between the closure and the container if no venting converter is applied; characterised in that a venting converter (12) is fitted as a liquid-tight, gas-venting seal between the closure (10) and container (48), the converter being shaped and configured to by-pass the sealing member (40) of the container-closure combination; whereby, in use, a venting gas path is provided from the inside of the container through the venting converter to atmosphere via the complimentary non-gas tight features (52,54).
A combination as claimed in claim 3 and further characterised in that the venting converter (12) is a microporous member (24).
A combination as claimed in claim 3 or claim 4 and wherein the closure is a cap (14) having an integral sealing member (40) and the container (48) has a neck (44), the cap and neck having the complimentary features (52, 54) and further characterised in that the venting converter is an insert (12) for the cap (14) shaped to generally conform to the inner shape of the closure cap (14) and sealing member (40); whereby the venting converter can, in use, by-pass the sealing member.
A combination as claimed in claim 5 and wherein the sealing member is a sealing flange (40) depending from the cap (14), and further characterised in that the insert (12) has a corrugated rim portion (34) with two concentric peripheral grooves (36, 38) respectively opening upwards, to accommodate and by-pass the cap sealing flange (40), and downwards, to accommodate the rim of the container neck (44).
A combination as claimed in claim 6 and further characterised in that the cap-facing surfaces of said two concentric peripheral grooves (36, 38) are configured to form venting gas flow means between the insert (12) and the cap (14).
A combination as claimed in claim 6 or claim 7 and further characterised in that the insert (12) has a central aperture (16) closed on the liquid-side by a microporous membrane (24).
A combination as claimed in any of claims 5 to 8 and further characterised in that the insert (12) has a liquid-side capillary port (28) that, in use, acts to permit passage of gas and prevent passage of liquid to the venting converter (24).
A combination as claimed in claim 9 as dependent on claim 7 and further characterised in that a cup-shaped member (26) is mounted liquid-tight to the liquid side of the insert (12) with the microporous membrane (24) closing the mouth of the cup-shaped member; the capillary port (28) being formed in a wall of the cup-shaped member.
A combination as claimed in any of claims 5 to 10 and further characterised in that a sealing ring (58) is located between the neck rim (42) and the insert groove (38) to seal the insert (12) with the container (48).
A venting converter for a sealed container-closure combination as claimed in any of claims 7, 8, 9 or 10 when dependent upon claim 6 and claim 11 when dependent upon any of claims 6 to 10.