AU731992B2

AU731992B2 - Vented closures

Info

Publication number: AU731992B2
Application number: AU49572/97A
Authority: AU
Inventors: Michel Boulange; 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: 2001-04-12
Anticipated expiration: 2017-11-18
Also published as: DE69718934D1; AU4957297A; JP2001504068A; DE69718934T2; EP0954487B1; WO1998022363A1; BR9714638A; CN1100709C; EP0954487A1; CN1237938A; ES2191832T3

Description

-1- VENTED CLOSURES 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 closures.

A known type of container closure is a cap having a none-gas tight screw thread fitting with the complimentary thread neck of a container and a seal in the cap to form a gas- and liquid-tight seal with the container neck. 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 0to 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.

Document WO-A-9526913 discloses a bi-directional venting liner as an original part of a cap closure fora bottle or the like container.

Object of the Invention It is an object of the present invention to overcome or ameliorate some of the disadvantages of the prior art, or at least to provide a useful alternative.

S•Summary of the Invention There is firstly disclosed herein a method of converting a sealed closure to a i 20 vented closure for a container, the closure and container having complimentary, non-gas tight features by which the closure may be removably attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container; further including adding a venting converter to by-pass the sealing member and form a liquidtight, gas-venting seal between the closure and the container and provide a venting gas 25 path from the container through the venting converter to atmosphere via the ~complimentary closure and container features.

There is further disclosed herein a venting converter for a container having a :sealed closure, the closure and container having complimentary, non-gas tight features by which the closure may be removably attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container wherein the venting converter is shaped and configured to by-pass the sealing member of a given closure and container and to fit as a liquid-tight, gas-venting seal between the closure and container; S whereby, in use, a venting gas path is provided from the container through the venting [R:\LIBLL] 10544specie.doc:keh -2converter to atmosphere via the complimentary closure and container none gas-tight features.

Unlike the disclosure of Document WO-A-9526913, no modification by the removal of an existing sealing insert is required when using the method of a preferred embodiment of the present invention; all that is necessary is to add a venting converter.

Also according to a preferred embodiment of the present invention, a venting converter is shaped and configured to by-pass the sealing member of a given closure and container and to fit as a liquid-tight, gas-venting seal between the closure and container, which have complimentary, non gas-tight features by which the closure may be removably attached to the container; whereby, in use, a venting gas path is provided from the container through the venting converter to atmosphere via the complimentary closure and container features.

Thus, a liquid container can be provided with a gas vent according to an embodiment of the present invention simply and economically; no modification of the container or closure being required, simply the provision of a suitable venting member together with 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.

*o 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.

25 In a preferred embodiment of the present invention the closure is a cap having a sealing member and the container has a neck, the cap and neck having the complimentary features, and 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. The cap may have a depending sealing flange 30 and the insert 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 cap-facing surfaces of RA said two concentric peripheral grooves can be configured to form venting gas flow means between the insert and the cap.

[R:\LIBLL] I 0544specie.doc:keh -3- In a further embodiment of the present invention, the insert has a liquid-side capillary port that, in use, acts to permit passage of gas and prevent passage of liquid to the venting converter. The capillary port is dimensioned so that the surface tension of a liquid to be contained in the container prevents that liquid from normally contacting the microporous membrane; this both improves membrane efficiency by preventing membrane wetting and protects the membrane from liquid-induced forces and loads that may occur during operational use of the filled container.

Brief Description of the Drawings The above and other features of the present invention are illustrated, by way of 1o example only, in the Drawings; wherein:- Fig. 1 is a cross-sectional view of a microporous membrane vented closure for a liquid container in accordance with an embodiment of 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.

Brief Description of the Preferred Embodiments i 20 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 i 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"GORTEX®", that is •bonded, such as by welding, within the rib 22 to the rim 20 to form a liquid seal therewith.

*o o oooo [R:\LIILL] 10544specie.doceh WO 98/22363 PCT/GB97/03117 4 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; WO 98/22363 PCT/GB97/03117 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 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 either replacing or 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

1. A method of converting a sealed closure to a vented closure for a container, the closure and container having complimentary, non-gas tight features by which the closure may be removably attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container; further including 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 container through the venting converter to atmosphere via the complimentary closure and container features.

2. A method as in claim 1, wherein the venting converter is microporous.

3. A venting converter for a container having a sealed closure, the closure and container having complimentary, non-gas tight features by which the closure may be removably attached to close the container and a sealing member to form a fluid-tight seal between the closure and the container wherein the venting converter is shaped and configured to by-pass the sealing member of a given closure and container and to fit as a liquid-tight, gas-venting seal between the closure and container; whereby, in use, a venting gas path is provided from the container through the venting converter to atmosphere via the complimentary closure and container none gas-tight features.

4. A venting converter as in claim 3, wherein the venting converter is a 20 microporous member.

A venting converter as in claim 3 or claim 4, wherein the closure cap is a cap having a sealing member and the container has a neck, the cap and neck having the complimentary features and wherein 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.

6. A venting converter as in claim 5, wherein the sealing member has a sealing flange depending from the cap, and wherein the insert has a corrugated rim portion with two concentric peripheral grooves respectively opening upwards, to accommodate and by-pass the sealing flange, and downwards, to accommodate the rim of the container neck.

7. A venting converter as in claim 6, wherein the cap-facing surfaces of said two concentric peripheral grooves are configured to form venting gas flow means Sbetween the insert and the cap. [R:\LIBLL] 0544specie.doceh -7-

8. A venting converter as in claim 6 or claim 7, wherein the insert has a central aperture closed on the liquid-side by a microporous membrane.

9. A venting converter as in any one of claims 5 to 8, wherein the insert has a liquid-side capillary port that, in use, acts to permit passage of gas and prevent passage of liquid to the venting converter.

A venting converter as in claim 9, when dependent on claim 7, including a cup-shaped member mounted liquid-tight to the liquid side of the insert with the microporous membrane closing the mouth of the cup-shaped member; the capillary port being formed in a wall of the cup-shaped member.

11. A venting converter as in any one of claims 5 to 10, including a sealing ring located between the neck rim and the insert groove to seal the insert with the container.

12. A venting converter for a container, substantially as herein described with reference to any one of the embodiments of the invention shown in the accompanying drawings. Dated 2 February, 2001 Royal Packaging Industries Van Leer N.V. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON *i [R:\LIBLL] 10544specie.doc:keh