AU782439B2 - Drinking element - Google Patents

Description

1 DRINKING ELEMENT FIELD OF THE INVENTION The present invention relations to a liquid filtration drinking straw. Particularly, the invention relations to the filtration of drinking fluid using hollow fibre membranes, or more particularly a plurality of hollow fibre membranes contained within, attached to or part of a drinking straw.

BACKGROUND ART In many areas around the world water carries significant amounts of particulate matter which may present a serious health problem when the water is used as 15 a drinking supply. Many water supplies require treatment i to make them drinkable. Common types of disinfectants used today, especially by travellers going to countries which .have a water quality that may present a health problem, are chemicals such as chlorine and iodine. The use of 20 chlorine or iodine to disinfect water is time consuming, clearly inadequate in dealing with the new complex o"microbiological entities that exist in water, and these agents themselves may cause health problems.

Harmful organisms such as Giardia and cryptosporidium 25 are difficult to eradicate with conventional water treatment procedures.

Equipment used to treat drinking water includes different types of filter media disposed in a fluid line; for example, activated carbon or zinc and copper.

However, an activated carbon filter is not capable of reducing certain bacteria such as E.coli and pseudomonas.

Furthermore, zinc and copper filters cannot substantially eliminate bacteria in unchlorinated water.

2 US 5,688,588 discloses a drinking straw that includes a filter plug made of a non-woven fibrous structure.

However, because of inherent limitations in the construction of a plug filter per se the drinking straw is ineffective in filtering out smaller bacteria. Table 1 of US 5,688,588 confirms this, wherein a log reduction of means that around 0.5% of bacteria still passes through the straw, with potentially fatal or severe consequences.

US 5,681,463 discloses a filtering cartridge 16 which is screwed down over a bottle 10. The filtering member includes a housing 18, in which is positioned an activated carbon tube, which in turn surrounds a hollow fibre module which is fastened in the housing 18. Thus, the invention disclosed in this document relates to an arrangement for 15 mounting on bottles.

S. US 4,636,307 discloses a hollow fibre filtering module for positioning in a water purifying device. The device is intended as a permanent installation and does not have portable characteristics.

20 JP 63-287593 discloses a straw-type water purifier. A module case 2 is mounted within a main body case 3. The module case 2 has a number of hollow thread membranes which are closed at their lower end by a pre-filter 4. The arrangement is somewhat cumbersome in that a packing seal ee.eei S 25 11 is required at a lower end of the straw to seal the module case in place and to prevent water from passing between the main body case 5 and the module case 2. If the packing seal 11 were to fail, then a user could drink contaminated liquid with the possible risk of illness or death.

US 5,518,613 discloses a personal portable water purifying and drinking device. This device includes a conduit having a chemical purification stage positioned at 3 one end of the conduit, and a filtration stage positioned at the opposite end of the conduit. The filtration stage includes a filter and a cleaning medium. The filter is embodied as microfiltration membrane 38 or respectively. The microfiltration membrane 38 is embodied in the form of a disk and is larger then the diameter of the conduit. The other microfiltration membrane 50 has a form of about a paraboloid and is mounted a mounting points 52 to the walls of a residence chamber 26.

WO 99/29394 discloses a universal filter for soda pop and bottled water bottles. This filter comprises a housing with an elongated housing body. A carbon block filter member is provided inside of the housing body. The carbon oblock has a tube-like construction with a centre hole. At 15 the lower portion of the sidewalls of the housing inlets are provided so that water flows through these inlets and "".passes through the tube-like carbon block filter member.

S- The filter has a flange system for being sealingly fixed to a bottle neck. Furthermore, it is possible to add this .i:i 20 filter to the end of a straw.

US 5,546,831 shows a device to filter water having a 0 tubular housing with five chambers therein divided by filter members. The filter members have the form of disks.

The first chamber includes a granular activated carbon .ee.ei S" 25 filtering medium. The second chamber includes an iodinated anion resin filtering medium, the third chamber being empty, the fourth chamber includes an anion exchange filtering medium and the fifth chamber includes a granular activated carbon filtering medium.

US 5,509,605 shows a filtering straw for drawing liquid from a container. This filtering straw comprises a tube with a pair of filters, one filter being removably mounted in each end of the tube. The filters are formed 4 from bound powdered material. Each of the filters includes a portion extending into the corresponding end of the tube, each of which has an outer circumferential liquid permeable surface cooperating with the inner circumferential surface of the tube to define an annular chamber therebetween. Accordingly the cross sectional area through which fluid is drawn by sucking on the straw is the circumferential surface of each filter.

JP 04/322783 shows a water-purifying cartridge. This cartridge forms part of a housing for a water filtration installation. The cartridge comprises a bundle of hydrophilic porous hollow fibres which transmit water but no air, while the end of the bundle is embedded and fixed oooto a potting material. A hydrophobic porous material fibre 15 which transmits air but no water is wound around the bundle of hydrophilic porous hollow fibres and is embedded and fixed at its end part to the potting material. Thereby the hydrophobic material fibre discharges air, which prevents outward expansion of the bundle of the fibres.

20 JP 01-007907 relates to a separation membrane module for removing substances from an aqueous solution. This module comprises hydrophilic hollow yarns consisting of a hydrophilic material such as polyether sulfon.

Furthermore, this module comprises hydrophobic hollow oeooo S 25 yarns consisting of hydrophobic material such as polypropylene. When liquid is treated with this module the air initially present in the module permeates through the hydrophobic membrane and the aqueous solution permeates through the hydrophilic membrane. Thus, the air does not reduce the effective area of the hydrophilic membrane.

It would be advantageous if at least preferred embodiments of the present invention overcame or 5 substantially ameliorated at least one of the above disadvantages and/or more generally, provided an improved drinking element.

SUMMARY OF THE PRESENT INVENTION The present invention provides a drinking straw for the drinking of liquid comprising a mouthpiece having an outlet that is shaped for positioning in the mouth of a drinker of the liquid; a hollow conduit integral with or mounted to the mouthpiece and extending downwardly therefrom in use; a head mounted within and extending completely across the conduit; and a plurality of hollow fibre membranes, each membrane formed separately to the o head, each membrane having an open end that is 15 incorporated into and supported in the head, each membrane extending freely away from the head for positioning in the liquid, and each membrane defining a chamber therewithin; wherein, when each membrane is positioned in the liquid and the drinker applies a suction force to the outlet, 20 liquid passes across the membrane and into the chamber and *is filtered thereby, and then passes from the chamber via the open end to the outlet.

By employing hollow fibre membranes, very fine (e.g.

microfiltration) membrane materials can be employed, 25 without a restricting or limiting pressure drop the membrane can be made relatively thin). Such fine filtration characteristics cannot be achieved with filter plugs because, with reduced pore size the pressure drop becomes too excessive across the plug. Hollow fibre membranes are also highly efficient at filtration and are easily arranged within the conduit.

The mouthpiece is typically a separate part.

6 Preferably the membranes are one or more hollow fibre membranes. Alternatively, the membranes are one or more hollow ceramic or metal membranes.

Preferably the membranes have a predetermined pore size or sizes for filtering varying sizes of particulate matter in the liquid to be drunk. Typically the pore size of the filtration membranes is sufficiently small to filter out particles at a micro level less than and even to an ultra filtration level less than 0.05pm and down to 0.02gm).

Preferably the outlet surrounds or is located at the head.

Preferably, the membranes are mounted within the e conduit to provide a protective sleeve for the membranes.

15 As a further option, a carbon filter (e.g.

S"manufactured from activated carbon) can be arranged at the support such that liquid passing out of the or each S"membrane passes through the carbon filter. The carbon filter helps remove organics, some of which can pass 20 through very fine pore-size filters. However, organics are generally of less concern than living organisms such as bacteria.

Preferably the open end of the or each hollow fibre membrane is fasteningly supported in the head, and *fee*: 25 preferably the head is a bung fastened in the conduit adjacent to the outlet.

Preferably each hollow fibre membrane projects freely from the head either in a closed loop with opposite open ends supported in the head, or as a strand having a single open end supported in the head and a closed remote end.

The outlet or support can also be provided with suitable embossments or threading etc to enable the drinking element to be snap, screw or interface fitted 7 into a container, flask, bottle or other vessel that houses a liquid requiring filtering.

The present invention therefore provides a drinking straw adapted for the filtration of liquids, especially water, such that the liquid after passing through one or more hollow filtration membranes is delivered filtered and purified to a person's mouth.

BRIEF DESCRIPTION OF THE DRAWINGS Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: •g:Figure 1 is a plan view of a preferred drinking straw oooo 15 in accordance with the present invention; S. Figure 2 is a cross-sectional size view of the drinking straw shown in Figure 1 taken along line C-C; S. Figure 3 is a schematic cross-sectional side view of a hollow fibre filtration element for use in a straw in :i*i 20 accordance with the present invention; *Figure 4 is a cross-sectional plan view taken along line D-D in Figure 2; Figure 5 is a plan view of an alternative drinking straw in accordance with the present invention; S 25 Figure 6 is a cross-sectional side view of the drinking straw of Figure 5 showing a mouthpiece fitted to the end of the straw; Figure 7 is a cross-sectional side view of a further alternative drinking straw in accordance with the present invention with a mouthpiece fitted to the end of the straw; Figure 8 is a schematic cross-sectional side view, similar to Figure 3, but of an alternative hollow fibre 8 filtration element for use in a straw in accordance with the present invention; and Figures 9 and 10 are cross-sectional side views of two further alternative drinking straws in accordance with the present invention, when the membrane is a ceramic or metal material.

MODES FOR CARRYING OUT THE INVENTION Referring to the drawings, in Figures 1 and 2 a drinking straw 1 comprises a tube 16 having an open suction end 2 and an opposing mouth end 3, with a passageway 13 therebetween. A sealing head in the form of a bung 4 is positioned in passageway 13 to close mouth end and a filtration element 5 extends therefrom. The oooe e 15 element 5 is a filter made of a plurality of hollow fibre membranes 7, disposed within the tube 16, typically such i that the two open ends of each fibre strand 7 are e incorporated and supported in the bung 4.

Referring now to Figures 3 and 8, it can be seen schematically how liquid travels across and into each fibre 7 as indicated by arrows AA and is delivered to a drinker's mouth at the open end(s) of each fibre at end 3 of the straw. Thus, suction or negative pressure is created in the straw 1 by a drinker's back-suction 25 (indicated by arrows BB) and this causes the liquid to pass across the membrane wall and into an interior (chamber) thereof and then out of the open end(s) to a user's mouth. The individual fibres 7 are typically formed of polyethylene, polypropylene or the like (as described below). Also, in Figure 8, instead of a plurality of loops of hollow fibre membrane, a plurality of individual strands 14 are provided, each having a closed (sealed) end 9 In use, the fibres 7, 14 are partly or wholly submerged within a liquid 6 requiring filtration such that when a suction force is applied to the straw, the liquid passes through the pores of the fibre 5 leaving some (typically most) or preferably all of the solids, impurities, organisms, organics, etc. in or on the pores of the fibre.

As appropriate, bung 4 can support or be defined by a porous carbon filter (typically employing activated carbon) to filter out any organics and the like in the liquid.

Referring now to Figures 5 and 6, where like reference numerals are used to denote similar or like ee: parts, the drinking straw 1 includes a mouthpiece oooo 15 having a protrusion 9 shaped such that it fits comfortably g in a user's mouth. The mouthpiece includes a passageway 12 therethrough. An opposing skirt 11 is shaped such that it fits over the end 3 of the tube 16 but so as not to block the open ends of the fibres. The mouthpiece 10 may be 20 permanently attached to the straw 1 or can be removed manually as required, such as by unscrewing for use S. *S of the straw by different persons). Alternatively, the ego* straw itself may be formed moulded) as a single .0 piece to include the shape of the mouthpiece.

S" 25 The bung 4 is arranged so as to dispose the filter in a selected area of the straw 1, and only permits the passage through the straw of filtered liquid 6 via the pores of the filter 5. Thus, the filtered liquid only exits through the open ends of the membrane and does not otherwise traverse the bung 4.

The tube 16 can also be provided with one or more holes 8 to allow the passage of air out of the straw, to prevent pressure build-up in the interior of the tube 16, 10 created when submersing and then sucking at the drinking straw 1 in the liquid to be filtered.

Referring now to Figure 7, where like reference numerals denote similar or like parts, the bung 4 is now positioned solely in skirt 11 of mouthpiece 10. In this case, tube 16 is omitted and the filtration element (typically being a filter made of a plurality of hollow fibre membranes) hangs freely in the drinking straw (either as loops 7 or strands 14). However, chambers into which filtered liquid passes are defined on the other side of such membranes.

Rather than (or in addition to) employing hollow fibre membranes, flat filter membranes can be employed 6 (eg. at intervals within tube 16 or at the underside of bung 4, mouthpiece 10 etc), but so as to define a cavity on the other side thereof into which filtered liquid flows before exiting the straw.

The external surface of tube 16 or mouthpiece 10 can be provided with appropriate embossments, protrusions, 20 threading etc which enable the straw to be fitted to an &boo &outlet of a container, flask, bottle or other vessel holding a liquid requiring filtering. Such fitting can be see* *snap or interference fitting, screw fitting, friction S""fitting etc. When the tube or mouthpiece is to be fitted S 25 to an externally threaded outlet of a flask, bottle or the like, it can include an integral annular skirt that is internally threaded for mating with the outlet thread. In this case, the tube or mouthpiece would project into the outlet whilst the annular skirt would surround the outlet and mate therewith.

Referring now to Figures 9 and 10, where like reference numerals are used to denote similar or like parts, the filter element 5 is now defined to be a solid 11 filtration membrane 18 having one (Figure 9) or a plurality (Figure 10) of hollow tubular passageways defined therein and open at their upper end(s).

Typically, the membrane 18 is formed from either a ceramic material or a metal material having a plurality of micropores 22 defined therein. The tubular passageways define a chamber into which filtered liquid passes, before leaving the element at end 3. The use of mouthpiece 10 is optional but preferred. There is no suction end 2 in the arrangements of Figures 9 and 10 as liquid can pass through the membrane over the entire surface thereof.

Many other modifications and alterations are included within the scope of the present invention. For example, ;the drinking straw may be provided with two sealing means 15 (bungs) placed at each end of the straw.

Also, the drinking straw may be provided with the •hollow fibre membranes located partly or wholly outside the tube 16. The suction end can also have one or more passages laterally disposed or protruding from the side 20 wall of the straw for simultaneous use by multiple 00 users) Typically, the hollow fibre membranes are ultra micro-filtration membranes formed from polyethylene (or similar) in a melt spinning and drawing process, such as .oo:o those produced by Mitsubishi Rayon Co. Ltd. Such membranes have a pore size located between the micro filtration range (0.02tm 5 tm) and the ultra filtration range (2nm 0.05tm) and can filter out fine particles and all bacteria including colloidal silica, bacterial virus, oil emulsions, latex emulsions, cholera bacillus, typhoid bacillus, Escherichia coli, staphylococcus, cryptosporidium, Giardia and Echinococcus granulosus.

12 Typically, such membranes are also treated to be hydrophilic covered with a hydrophilic polymer) so as to be wettable in water.

Typically, the ceramic filter is a ceramic element having a microporous structure, such as those manufactured by British Berkefeld or Foseco International. Such filters typically filter particles down to around 0.5pm in size.

Silver metal can also be dispersed throughout the ceramic to prevent the growth of bacteria. Ceramic filter materials include porous clays, ceramic foam filters, silicon carbide and recrystallised silicon carbide materials.

Typically, the metal filter is a sintered metal filter or a laser cut metal filter. These can be in the S" 15 form of a tube filter defined by a sintered 5-layer plate, metal powder or metal fiber such as those manufactured by S"Jeongsan Enterprise Inc., or a metal filter cartridge such as those manufactured by Hanyang Engineering Co. Iron cellular filters and aluminium light weight foam filters *ii. 20 such as those manufactured by Foseco International may also be employed.

Whilst the invention has been described with reference to a number of preferred embodiments, it should be appreciated that the invention can be embodied in many other forms within the scope of the claims.

It is to be understood that a reference herein to a prior art publication does not constitute an admission that the publication forms a part of the common general knowledge in the art in Australia, or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as 13 "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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Claims (9)

1. A drinking straw for the drinking of liquid comprising: a mouthpiece having an outlet that is shaped for positioning in the mouth of a drinker of the liquid; a hollow conduit integral with or mounted to the mouthpiece and extending downwardly therefrom in use; a head mounted within and extending completely across the conduit; and a plurality of hollow fibre membranes, each membrane formed separately to the head, each membrane having an open end that is incorporated into and supported o* in the head, each membrane extending freely away from o 15 the head for positioning in the liquid, and each membrane defining a chamber therewithin; wherein, when each membrane is positioned in the e• liquid and the drinker applies a suction force to the outlet, liquid passes across the membrane and into the chamber and is filtered thereby, and then passes from the chamber via the open end to the outlet.

2. A straw as claimed in claim 1, wherein the outlet .o surrounds or is located at the head.

3. A straw as claimed in claim 1 or 2, wherein the open end of each membrane is fastened within the head.

4. A straw as claimed in any one of the preceding claims wherein the head is a bung fastened in the conduit adjacent to the outlet.

A straw as claimed in any one of the preceding claims, wherein each membrane projects freely from the head, either in a closed loop with opposite open ends mounted within the head, or as a strand having a single 15 open end mounted within the head and a closed opposite remote end.

6. A straw as claimed in any one of the preceding claims, wherein the conduit surrounds the membrane for a length thereof, the conduit having an open in-use lower end through which liquid is drawn into the straw.

7. A straw as claimed in any one of the preceding claims, wherein a carbon filter is arranged at the mouthpiece, such that liquid passing out of the open end of the membranes passes through the carbon filter.

8. A straw as claimed in any one of the preceding claims wherein the head is defined by a carbon filter.

9. A straw as claimed in any one of the preceding claims wherein an external surface of the mouthpiece or conduit 15 is shaped to enable the straw to be fitted in an outlet of "a container, flask, bottle or vessel. A drinking straw substantially as herein described S"with reference to the examples and/or the accompanying drawings. 0 Dated this 17 th day of March 2005 AKIRA CHIBA and RAZMIK MIKAELIAN By Their Patent Attorneys oGRIFFITH HACK