WO2011023644A2

WO2011023644A2 - Container for liquid storage

Info

Publication number: WO2011023644A2
Application number: PCT/EP2010/062201
Authority: WO
Inventors: Christopher Paul Ramsey; Thomas Hedley Maxwell-Wood; Jean-Marc André RICHEUX
Original assignee: Crown Packaging Technology, Inc.
Priority date: 2009-08-26
Filing date: 2010-08-20
Publication date: 2011-03-03
Also published as: ES2545982T3; EP2470377B1; WO2011023644A3; RU2012111213A; EP2470377A2; GB0914832D0; RU2554010C2

Abstract

This invention concerns a container for liquid storage, such as paint, comprising a lid and a can body whereby in placing the lid onto the can body, a channel is defined by the adjacent surfaces of the lid wall and the can body. This channel may provide a capillary channel within which the liquid in the container may move towards the seal between the lid and the can body. Accordingly, one or both of the adjacent surfaces defining the channel is adapted to define a chamber. The chamber is used to prevent liquid from wicking into the region approaching the seal, thereby avoiding subsequent openability issues for the consumer.

Description

Container for liquid storage

Technical Field

[0001] This invention relates to a metal container for liquid storage and in

particular, but not exclusively, for liquids such as paint and oil used domestically. Typically, the containers have a volume of 20 litres or less.

Background Art

[0002] It is commonly known to provide metal containers for packaging paint, in which the container has a can body with seamed or integral base, optionally a metal ring which is seamed to the open end of the can body, and a press-on lid which can be opened either by hand or with a tool such as a screwdriver.

[0003] The present applicant's filed WO 2006/089819 A (CROWN PACKAGING TECHNOLOGY) 17.01.2006 relating to a lid structure composed of a metal disc and plastics ring, which is easy to remove from a filled container by hand. A later application, WO 2008/125639 A (CROWN PACKAGING TECHNOLOGY) 11.04.2008 related to modification of the lid structure to achieve the legislative requirements of improved abuse resistance for the carriage of dangerous goods.

[0004] 'Compound' or 'lining' is often used to provide a primary seal between the lid and the can body or if used the metal ring, preventing the ingress of oxygen (which may cause skinning of the product) and foreign articles such as insects into the container and the product contained therein. It acts to provide an airtight seal preventing the loss of moisture and/or any solvent vapour from the paint. Furthermore, the compound prevents the product from leaking out of the container.

[0005] During the tinting process, the container is cyclically rotated and vibrated to ensure adequate mixing of colours and this has been found to cause product splashing and then 'wicking' into the region approaching the compound. The splashes of paint dry later and render the container difficult to open by hand by the consumer. This problem has been found to occur during transit too, following vibration.

[0006] Wicking or capillary action as it is more commonly known, is the tendency of a liquid to rise in narrow tubes or to be drawn into small openings, such as those between small grains of rock. It is the result of molecular attraction within the liquid and solid materials and otherwise is an essential process for carrying substances and nutrients from one place to another in plants and animals.

Disclosure of the invention

[0007] A container for liquid storage, comprising a lid and a can body,

- the can body having a body wall which defines an open end, and

- the lid having a seal arranged to seal the open end of the can body when the container is closed, and

- the lid having a lid wall, which lies adjacent to a portion of the can body wall to define a channel terminating at the seal, characterised in that one or both of the adjacent portions of the body wall and lid wall further provides a chamber arranged to interrupt any movement of the liquid before it reaches the seal.

[0008] The chamber brakes the surface tension forces, which drive capillary

action, effectively preventing any paint from wicking along the channel towards the compound. The chamber also provides an enlarged space in which any paint already wicking from the container along the channel may collect. With paints containing solvent, it is undesirable for the paint to reach and make contact with the compound, as the solvent will attack the compound and render it less effective. Any paint splashes that

successfully enter the channel will wick along the channel and then collect in the chamber, which brakes the capillary action. The paint will not proceed further along the channel towards the compound.

[0009] According to one aspect of the invention, the chamber may be formed by a profile in the lid wall or the can body, or both the lid wall and the can body. This flexibility of choice offers maximum design freedom with regard to both the container aesthetics and also for the choice of manufacturing process.

[0010] In a preferred embodiment of the invention, the channel further comprises a "panel seal", which describes the radial fit of the lid to the can body at a particular point. The can body wall has a slight vertical taper such that the can body wall is not absolutely vertical, i.e. the diameter of the can body at its closed end is smaller than the diameter of the can body at its open end. The purpose of this taper is to facilitate easy stackability of empty can bodies during storage. Where the lid interfaces with the can body at its lowest point vertically, the outside diameter of the lid is greater than the inside diameter of the can body, thereby producing an interference fit. For example, if the outside diameter of the lid is 300.3mm, the inside diameter of the can body is 300mm, and the diametral interference is 0.3mm. Only the section of the lid wall and can body interface that has an interference fit is called the panel seal.

[0011] The panel seal advantageously prevents splashes of paint from easily entering the channel.

[0012] According to a second embodiment of the invention, the container is

substantially round or oval, and the chamber extends around its entire periphery.

[0013] The shape of the chamber has been found to be insignificant, though a smooth curved profile in cross section is relatively easy to implement. The width of the chamber is however important in relation to the width of the channel. In practice, the inventors have found that the width of chamber cross-section is preferably greater than the container material gauge.

[0014] Also, it is preferable to have the chamber extending around the entire

periphery of the container so as to avoid paint splashes from collecting at specific points around the periphery. This ensures that whatever the axial orientation of the container, the consumer will always be able to open the container by hand.

[0015] Preferably, at least a portion of the container is made of metal and the profile of the chamber is formed using a rolling process. Metal containers are easily recyclable and generally better for the environment than alternative materials such as plastic. A rolling process produces an accurate chamber profile. In the rolling process, complementary rotating discs are radially brought to the axial wall (be it for a lid or a can body), impinge on that wall and then shape it, resulting in a profile.

[0016] In an additional embodiment of the invention, the container further comprises a plastic annulus. The annulus is initially fixedly placed onto the outwardly extending annulus of the lid wall, to protect users from any cut edges. When the lid is placed on the can body, the plastic annulus extends over the can body curl and snaps into place underneath the curl, thereby securing the lid to the can body. If the filled container is accidentally dropped, the lid is prevented from leaving the can body and liquid product spills are thereby avoided. Moreover, should paint splashes enter the channel and succeed in reaching the primary seal area despite the security of the panel seal and the chamber, the plastic annulus will provide leverage for the consumer to help manually remove the lid. This is especially so if the channel also comprises a panel seal as with the interference fit the container will be automatically much more difficult to open than a container without the panel seal.

[0017] In yet another embodiment of the invention, the plastic annulus comprises circumferentially spaced openings. These openings each provide a point at which a tool may be inserted into the plastic annulus to assist removal of the lid. This is useful if splashes of paint reach the area of the primary seal rendering the container difficult to open by hand. Certain demographs such as the elderly will appreciate the option of being able to use a tool to assist them in removing the lid from the can body.

[0018] Embodiments with a plastic annulus may additionally comprise locking tabs. These tabs are circumferential sections of annulus, which are designed to be detachable from the annulus itself by way of a plurality of plastic bridges. Part of each/any tab is adapted to provide a gripping feature, indicating which end of the tab the consumer should break.

[0019] The purpose of the tab sections is to introduce some flexibility into the plastic annulus once the tabs have been removed from the annulus. For example, the consumer can make a round annulus oval without the tab sections in place on the annulus, creating just a little extra diametral clearance that will assist the consumer in removing the lid from the container.

[0020] This invention is particularly suitable for use with liquids, such as paint, that are found to adhere chamber to containers, more especially to metal containers, and therefore the containers where the majority of openability issues may be found.

Brief description of drawings

[0021] A preferred embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings, in which

[0022] Figure 1 is a schematic of a capillary tube, which is a commonly used

piece of laboratory apparatus used to demonstrate the phenomenon of capillary action.

[0023] Figure 2 is a schematic cross-section illustrating a container 1 , which may be commonly found on the market. A channel 6 as may be found in the prior art is clearly shown.

[0024] Figure 3 is a schematic cross-section of one embodiment of the invention, illustrating a chamber 3, arranged to brake any product (not illustrated) from wicking along the channel between adjacent surfaces of the can body 5 and the lid wall 2 by capillary action. The location of any panel seal 17 [the feature locking the lid to the container omitted for clarity] is also illustrated.

[0025] Figure 4 is a schematic cross-section of the embodiment of the invention shown in figure 3 incorporating a plastic annulus 16.

[0026] Figure 5 is a perspective cross-section of a container, comprising a plastic annulus 16 with an opening 18.

[0027] Figure 1 is used as a reference to explain the process of capillary action.

When the lower end of a capillary tube 13 is placed in a liquid 11 , liquid 11 moves within the capillary tube 13 and will reach a level that is higher than its normal bulk level 10 of liquid 11 in the container. That equilibrium position is determined by the balance of the surface tension force and the gravity force acting on the column of the elevated liquid. The rise height 12 will increase as the radius of the tube 13 is made smaller [note: diameter 14 is twice the radius], as can be seen in the following equation taken from Professor Batchelor's classic text¹ on fluid dynamics: H -

pgr h = rise height (12)[m],

T= surface tension [Nm^'1], θ = angle of contact 15 of the liquid 11 with the capillary tube 13 [radians], p = density of the liquid 11 [kgnrf³],

g = standard acceleration due to gravity [ms^"2], and

r = radius of the capillary tube 13 [m].

Mode(s) for carrying out the invention

[0028] Referring to Figure 2, the lid for a container 1 has a radially horizontal centre panel 4, and a substantially axially vertical wall 2, terminating in a radially outwardly extending annulus 8. As a primary seal, compound 9 sits on the underside of the outer annulus 8.

[0029] In use, when the lid is placed on the can body 5, the compound 9 will contact the can body curl 7 and a channel 6 will form in between the two adjacent surfaces of the lid wall 2 and the upper edge of the can body 5. This channel 6 provides a pathway for liquid to wick.

[0030] In Figure 3, a chamber 3, axially located along the channel 6, is also

formed by the adjacent surfaces. Also shown is a panel seal 17, situated axially below the chamber 3 and the compound 9.

[0031] The plastic annulus 16 of one preferred embodiment may be seen in

Figure 4. The plastic annulus 16 is located radially outwards of the lid wall 2 and upper edge of the can body 5 and it protects the consumer from the cut edge of the radially outwardly extending annulus 8. Its primary purpose is to improve the openability of the lid should paint splashes ever reach the channel 6 and the compound 9 and the area in between.

[0032] As illustrated in Figure 5, the plastic annulus 16 of the preferred

embodiment of the invention may additionally have one or more openings 18 to allow a tool, such as a screwdriver (not shown), to be inserted into the opening 18. Thus the openings 18 allow the consumer to provide leverage for help with manual removal of the lid, if required.

[0033] ¹BATCHELOR₁ George Keith. An Introduction To Fluid Dynamics.

Cambridge University Press , 1967. ISBN 0521663962.

Claims

1. A container (1 ) for liquid storage, comprising a lid (2, 4) and a can body (5),

- the can body (5) having a body wall which defines an open end, and

- the lid (2,4) having a seal (9) arranged to seal the open end of the can body (5) when the container is closed, and

- the lid having a lid wall (2), which lies adjacent to a portion of the can body (5) wall to define a channel (6) terminating at the seal (9)

characterised in that one or both of the adjacent portions of the body wall and lid wall (2) further provides a chamber (3) arranged to interrupt any movement of the liquid before it reaches the seal (9).

2. A container (1) for liquid storage according to claim 1 , wherein

- the open end of the can body (5) has a curl (7), and

- the lid has a substantially axially vertical wall (2) terminating in a radially outwardly extending annulus (8), with a primary seal (9) axially located on the underside of the annulus (8),

whereby in use, when the primary seal (9) is placed on the can body curl (7), the two adjacent surfaces of the lid wall (2) and the can body (5) define a channel (6) in axial alignment with the primary seal (9) and the channel (6) further provides a chamber (3).

3. A container (1) according to claim 1 or claim 2, wherein the channel (6) further comprises a panel seal (17).

4. A container (1 ) according to any of the above claims, wherein the container is substantially round or oval, and the chamber (3) extends around the entire periphery of the container.

5. A container (1) according to any of the above claims, wherein at least a portion of the can body (5) and/or the lid (2, 4) of the container is made of metal and the profile of the chamber (3) is formed using a rolling process.

6. A container (1 ) according to any of the above claims, wherein the lid (2, 4) further includes a plastic annulus (16).

7. A container (1) according to claim 6, wherein the plastic annulus (16)

additionally includes circumferentially spaced openings (18).

8. A container (1) according to claims 6 or 7, wherein the plastic annulus (16) further includes locking tabs.