GB2276324A

GB2276324A - Flatus filter

Info

Publication number: GB2276324A
Application number: GB9313194A
Authority: GB
Inventors: Nicholas Steven Shelley; Rory James Maxwell Smith
Original assignee: Welland Medical Ltd
Current assignee: Welland Medical Ltd
Priority date: 1993-03-08
Filing date: 1993-06-25
Publication date: 1994-09-28
Anticipated expiration: 2013-06-25
Also published as: GB2276324B; GB9304658D0; GB9313194D0

Abstract

The filter 1 has a first surface 4 for attachment to an ostomy bag or the like over an opening in a wall thereof and comprises a layer 7 of deodorising material enclosed within a covering structure 4, 5, at least a portion 5 of the covering structure adjacent or opposite said first surface being defined by a gas-permeable, substantially water impervious polymeric foam material. Alternatively, the filter may comprise first and second gas-impermeable layer sandwiching an inner layer formed of a body of deodorising material bounded by a ring of the polymeric form material (Fig. 4). <IMAGE>

Description

FLATUS FILTERS The present invention relates to a flatus filter for use with ostomy bags, wound drainage bags and like bags for receiving bodily waste materials.

More particularly, the present invention provides a flatus filter having a first surface for attachment to an ostomy bag, wound drainage bag or like bodily waste receiving bag over an opening in a wall thereof, the flatus filter comprising a layer of deodorising material enclosed within a covering structure, at least a portion of the covering structure adjacent or opposite said first surface being defined by a gas-permeable, substantially water impervious polymeric foam material.

The present invention also provides an ostomy bag, wound drainage bag or like bodily waste receiving bag having secured thereto about an opening in a wall thereof a flatus filter as hereinbefore defined.

The deodorising material can be, for example, a layer of activated charcoal cloth, or a layer of foam matrix containing activated charcoal particles.

The deodorising material can be surrounded substantially entirely by gas-permeable, substantially water impervious polymeric foam material. Alternatively, part of the covering structure can be defined by a gasimpermeable material.

The flatus filters of the present invention are constructed in such a way as to minimise the potential for blockage of the filter by the contents of the ostomy bag or like bag. Water-based waste material is prevented from penetrating the filtering element by the hydrophobic polymeric foam material. The effectiveness of the filter is therefore not prejudiced and there is risk of the escape of waste material from the ostomy bag via the filter element.

In one embodiment, an outwardly facing surface opposite said first surface can be defined by a gasimpermeable material, and a lateral surface adjacent said first surface can be defined by the foam material.

The first surface, i.e. the surface which is secured to the ostomy bag or like bag, can be formed of a gaspermeable or gas-impermeable material, except that where it is formed of a gas-impermeable material, it is provided with an opening permitting gas flow therethrough.

In one particular embodiment, the filter is of a sandwich structure comprising first and second outer layers formed of a gas-impermeable material, and sandwiched therebetween an inner layer comprising a body of deodorising material bounded by a ring of gas-permeable substantially water-impervious polymeric foam material, said first layer defining a first surface for attachment to an ostomy bag and having an opening therein permitting gas flow through the filter.

The gas-permeable substantially water impervious polymeric foam material can be, for example, a polyether polyisocyanate. Polyether polyisocyanate foams can be prepared by reacting a polyisocyanate-terminated polyether prepolymer with a protic substance, most particularly water. Polyisocycanate-terminated polyether prepolymers are commercially available under the trade name "Hypol" and can be obtained from W.R. Grace Limited, London, United Kingdom.

The flatus filters of the present invention can be secured over an opening in the wall of an ostomy bag or like drainage bag by means of a suitable adhesive or by welding.

In a particularly preferred embodiment, the filter comprises a layer of deodorising material having on a surface opposite the said first surface of the filter a layer of relatively gas-impermeable material, the layer of deodorising material having a lateral surface not covered by the relatively gas-impermeable material, wherein the said lateral surface and the layer of relatively gasimpermeable material are enclosed by a covering of the gaspermeable substantially water-impervious polymeric foam material.

In the foregoing embodiment, the first surface of the filter may be defined by a layer of hot melt adhesive for bonding the filter to an ostomy or wound drainage bag wall.

The hot melt adhesive layer can comprise, for example, a layer of polyethylene. The layer of polyethylene may be provided with a surface coating of an adhesive for bonding it to the layer of deodorising material.

The layer of relatively gas-impermeable material need not be absolutely impermeable to gases but should be sufficiently impermeable to ensure that flatus gases enter the layer of deodorising material preferentially through the lateral surface thereof, thereby providing a longer gas flow path to the opening in the ostomy bag wall. The relatively gas-impermeable material can be polyethylene, but materials such as polyvinyl chloride or polyvinylene dichloride, which have better gas barrier properties, can be used if desired.

The invention will now be illustrated, but not limited, by reference to the accompanying drawings in which:- Figure 1 is a side sectional elevation through a filter according to one embodiment of the invention; Figure 2 is a side sectional elevation through a filter according to a second embodiment of the invention; Figure 3 is a side sectional elevation through a filter according to a third embodiment of the invention; Figure 4 is a side sectional elevation through a fourth embodiment of the invention; Figure 5 is a schematic illustration of the method of construction of the embodiment shown in Figure 4; and Figure 6 is a side sectional elevation through a fifth embodiment of the invention.

As shown in Figure 1, a filter 1 can be fixed to the wall 2 of an ostomy bag or like drainage bag, so as to cover an opening 3 in the wall of the bag 2. The construction of the remainder of the ostomy bag is immaterial to the present invention and need not be shown here.

Filter 1 is generally circular in plan and comprises two sheets 4 and 5 of a polyether polyurethane material sealed together by welding around their peripheral edges 6 and enclosing a layer of activated charcoal fabric 7. The activated charcoal fabric is of a type produced by heating in a controlled atmosphere, and is obtainable from Charcoal Cloth Limited, Maidenhead, Berkshire, UK . The polyether polyurethane material used in the preparation of sheets 4 and 5 can be a "Hypol" (trade mark) polymer of a type distributed in the United Kingdom by W.R. Grace Limited, London, United Kingdom. An advantage of the form of construction illustrated in Figure 1 is that the greatest possible surface area is provided for the exit of flatus gases through the filter and the common problem of filter blockage is thereby overcome, or at least alleviated.

The filter 1 can be secured against the wall 2 of the ostomy bag by means of welding or the use of a hot melt adhesive.

A further embodiment according to the invention is illustrated in Figure 2. According to this embodiment, the invention provides a flatus filter of generally circular plan which comprises a layer of activated charcoal fabric 17 completely encased in a layer 14 of a "Rypol" polyether polyurethane. As with the embodiment shown in Figure 1, one surface of the filter is secured by means of welding, or more preferably a hot melt adhesive, to the wall 12 of an ostomy bag to cover an opening 13 in the ostomy bag wall. Filters of the type illustrated in Figure 2 can be prepared by dipping a disc of activated charcoal fabric in a polyether polyurethane prepolymer mixture prior to or shortly after the initiation of the foaming step through addition of water. An advantage of the construction shown in Figure 2 is its simplicity and ease of manufacture.

A further embodiment of the invention is illustrated in Figure 3 in which there is shown a filter 21 secured to the wall 22 of an ostomy bag so as to cover an opening 23 in the wall of the ostomy bag. Filter 21 comprises a circular disc 27 of activated charcoal fabric covered on its outwardly facing surface with a layer 28 of a gas impermeable material such as polyvinylene dichloride, and on its lateral and inwardly facing surfaces 24 with a layer of polyether polyurethane "Hypol" material. In this embodiment, flatus gases from within the ostomy bag pass into the filter 21 through the foam layer at lateral surfaces 29 and thence through activated charcoal fabric layer 27, layer 24 and then vent to atmosphere through opening 23 in the bag wall.

The embodiment shown in Figure 3 can be prepared by die cutting a disc of activated charcoal fabric, placing the disc onto a sheet of polyvinylene dichloride, pouring a liquid polyether polyurethane foam composition over the disc and allowing the foam to cure.

A fourth embodiment of the invention is illustrated in Figure 4, and comprises a filter 31 which in use is secured, e.g. by means of welding or a hot melt adhesive to the wall 32 of an ostomy bag so as to cover opening 33 in the ostomy bag wall. Filter 31 comprises two sheets 38 and 40 of a gas-impermeable material such as polyvinylene dichloride covering the inner and outer surfaces of a layer 37 of activated charcoal fabric. Sandwiched between the layers 38 and 40 of polyvinylene dichloride, is an annulus 39 formed of polyether polyurethane foam material.

In use, flatus gases pass into the filter through the polyether polyurethane foam material 39, and thence through the activated charcoal fabric layer 37, out through opening 41 in the innermost polyvinylene bichloride layer 40 and then vent to atmosphere through opening 33 in the ostomy bag wall.

In each of the embodiments of Figures 3 and 4, the polyvinylidene bichloride (PVDC) barrier layer can be replaced by barrier layers formed of other water and gas impermeable materials A method of preparing a filter of the type illustrated in Figure 4 is shown in Figure 5, and comprises preparing a sheet 50 of a polyether polyurethane foam, and die cutting circular recesses or holes 51 in the foam. Activated charcoal fabric discs 52 corresponding in diameter to the holes or recesses 51 in the foam are then inserted into the said holes or recesses and the two sides of the foam sheet are then covered sequentially or simultaneously with gas-impermeable polyvinylene dichloride film layers 53 and 54. The resulting sandwich structure is then die cut to form circular filters as shown.

A fifth embodiment of the invention is illustrated in Figure 6. According to this embodiment, the filter 61 comprises a layer of activated charcoal fabric 67, of the type described above, sandwiched between a polyethylene film layer 66 and a polyethylene film layer 65. The lateral surfaces of the activated charcoal fabric layer 67, and the polyethylene film layer 66 are enclosed by a covering 64 of the polyether polyurethane foam.

The polyethylene film layer 65 can be formed from an adhesive coated polyethylene film of the type sold by 3M of Loughborough UK under the code number 1527L. The adhesive coating is used to adhere the polyethylene film to the activated charcoal fabric layer 67 whilst the polyethylene itself serves as a hot-melt adhesive for bonding the filter 61 to the wall 62 of an ostomy bag. Polyethylene film layer 65 is provided with apertures to allow the passage therethrough of flatus gases.

The polyethylene film layer 66 is relatively impermeable to gases and serves to channel the flatus gases in through the lateral surfaces 68 of the charcoal fabric layer 67. An advantage of this arrangement is that the gas flow path through the charcoal fabric layer to the aperture 63 in the ostomy bag wall 62 is longer than would be the case if the flatus gases were to enter the charcoal fabric layer through surface 69, and consequently the deodorising efficiency of the filter is improved.

Instead of polyethylene, other relatively gas impermeable materials such as polyvinylchloride (PVC) and polyvinylidene dichloride (PVDC) may also be used.

It will readily be apparent that numerous modification and alterations can be made to the filters illustrated in the enclosed drawings, without departing from the principles underlying the present invention. All such modifications and alterations are intended to be embraced by this application.

Claims

1. A flatus filter having a first surface for attachment to an ostomy bag, wound drainage bag or like bodily waste receiving bag over an opening in a wall thereof, the flatus filter comprising a layer of deodorising material enclosed within a covering structure, at least a portion of the covering structure adjacent or opposite said first surface being defined by a gas permeable, substantially water impervious polymeric foam material.

2. A flatus filter according to claim 1 wherein the deodorising material is a layer of activated charcoal cloth, or a layer of foam matrix containing activated charcoal particles.

3. A flatus filter according to claim 1 or claim 2 wherein the deodorising material is surrounded substantially entirely by gas-permeable, substantially water-impervious polymeric foam material.

4. A flatus filter according to claim 1 or claim 2 wherein part of the covering structure is defined by a gas-impermeable material.

5. A flatus filter according to claim 4 wherein an outwardly facing surface oposite.said first surface is defined by a gas-impermeable material, and a lateral surface adjacent said first surface is defined by the foam material.

6. A flatus filter according to claim 1 wherein the first surface is formed of a gas-permeable material.

7. A flatus filter according to claim 1 wherein the first surface is formed of a gas-impermeable material and is provided with an opening permitting gas flow therethrough.

8. A flatus filter according to claim 1 wherein the filter is of a sandwich structure comprising first and second outer layers formed of a gas impermeable material, and sandwiched therebetween an inner layer comprising a body of deodorising material bounded by a ring of gas-permeable substantially water-impervious polymeric foam material, said first layer defining a first surface for attachment to an ostomy bag and having an opening therein permitting gas flow through the filter.

9. A flatus filter according to claim 1, the filter comprising a layer of deodorising material having on a surface opposite the said first surface of the filter a layer of relatively gas-impermeable material, the layer of deodorising material having a lateral surface not covered by the relatively gas-impermeable material, wherein the said lateral surface and the layer of relatively gas-impermeable material are enclosed by a covering of the gas-permeable substantially water-impervious polymeric foam -material.

10. A flatus filter according to claim 9 wherein the first surface of the filter is defined by a layer of hot melt adhesive for bonding the filter to an ostomy or wound drainage bag wall.

11. A flatus filter according to claim 10 wherein the hot melt adhesive layer comprises a layer of polyethylene.

12. A flatus filter according to claim 11 wherein the layer of polyethylene is provided with a surface layer of an adhesive for bonding it to the layer of deodorising material.

13. A flatus filter according to any one of the preceding claims wherein the gas-permeable substantially water impervious polymeric foam material is a polyether polyisocyanate.

14. A flatus filter substantially as described herein with reference to the accompanying drawings.

15. An ostomy bag, wound drainage bag or like bodily waste receiving bag having secured thereto about an opening in a wall thereof a flatus filter as defined in any one of the preceding claims.