GB2122090A - Fold-over filter for an ostomy bag - Google Patents

Abstract

A fold-over filter clip for use on an ostomy bag has first and second members 10 and 12 joined together or hinged together and made from a material which can be readily bent by human finger pressure. One of these members has a bag-puncturing spike 16 extending outwardly from a substantially flat surface thereon and having an adhesive covered by a strippable protective layer on the said surface. The other of the members has a substantially flat filter pad 32 of open-cell material carrying a gas- adsorber, e.g. activated carbon, disposed in a space in the second member complementary in shape to the pad. One surface of the pad is covered with an adhesive which is in turn covered by a strippable protective layer and the other surface of the pad is in engagement wlth a base wall. <IMAGE>

Description

SPECIFICATION Fold-over filter for an ostomy bag This invention relates to a fold-over filter for use with, and application to, an ostomy bag. The problem of flatus into such bags has exercised the mind of skilled men in this art for many years, and many efforts have been made to provide vents and gas filters associated therewith, whereby flatus gases discharged into an ostomy bag can be vented to the atmosphere, after having been filtered to remove at least most of their odorous contents. Examples of such efforts are the following British Patent Specifications:~ 785 562,1 117 204,1 295252,1363644, 1379464,1405032,1 462492,1416594, 1 541 565, 1 571 382, 1 550960,2059797 (application), 2 053 718(application).

It would be desirable to have a clip-on filter which can be manufactured in a simple and inexpensive manner and can be easily and securely attached to an ostomy bag, even by elderly or infirm persons, which does not require a hole to be punched in the bag wall in a separate preliminary operation, and, when once attached, is so constructed that gases leaving the bag are required to take a path of reasonable length through gas filtering material.

According to the invention, there is provided a fold-over filter clip for use on an ostomy bag, comprising first and second members joined together or hinged together and made from a material which can be readily bent by human finger pressure, one of these members (the first) having a bag-puncturing spike extending outwardly from a substantially flat surface thereon and having an adhesive covered by a strippable protective layer on the said surface, and the other (the second) of the members having a substantially flat filter pad of open-cell material carrying a gas-adsorber, e.g. activated carbon, disposed in a space in the second member complementary in shape to the pad, one surface of the pad being covered with an adhesive which is in turn covered by a strippable protective layer and the other surface of the pad being in engagement with a base wall.

In use, such a clip is bent over into U-shape embracing the top edge of an ostomy bag, after the strippable protective layers have been removed from the adhesive, and its two members are pressed together gripping a portion of the bag between them, so that the clip is securely held on the bag by the two adhesive layers. In this foldingover operation, the spike punctures both the front and the rear wall of the ostomy bag and the construction of the filter is such that exiting gases pass through the filter pad principally in a direction parallel to the said surface of the filter pad. That is to say, they pass to the exposed edge of the filter pad and therefrom into ambient atmosphere, having been effectively filtered by the activated carbon in or on the pad.

The two hinged or joined members are preferably moulded with an integral hinge from a mouldable synthetic plastics material such as polypropylene. Alternatively the two may be made from a single piece of metal such as aluminium or an aluminium alloy. The function of the members is to carry the filter pad and the spike respectively and any material which can be readily bent by finger pressure can be used. The spike can be integral with the first plate member or may be fixed thereto in any convenient manner.

In a preferred embodiment of the invention, a controlled porosity layer is located in juxtaposition with the filter pad, on the side of the filter pad which in use will be nearer the bag. Such a controlled porosity layer may be made from an open-cell foamed synthetic plastics material. It may also be termed a microporous membrane. Its function is to offer a controlled impediment to gases leaving the ostomy bag and passing into the filter pad, so that the gas pressure in the interior of the bag will not fall suddenly to such a level that the front and rear bag walls collapse into contact with each other. If this occurs, the wearer may suffer pain or discomfort as the outer bag wall contacts the sensitive end of the stoma, and free discharge of material from the stoma may be hindered.At the same time, the porosity of the layer is chosen so that the obstruction to escaping gases offered by the layer is not so great as to prevent adequate venting of flatus gases from the bag interior.

An example of the invention will now be described with reference to the accompanying drawings, in which:~ Figure 1 is a plan view of a filter clip according to one example of the invention showing two hinged members, seen in the open position; Figure 2 is an underplan view corresponding to Figure 1; Figure 3 is a vertical central cross-section through the filter clip of Figure 1; Figure 4 is a side elevation of the filter clip of Figure 1; Figure 5 is a section on A-A in Figure 2; Figure 6 is a front elevation of an ostomy bag showing a filter clip according to the invention attached thereto; Figure 7 is a top plan view of a filter clip according to a second embodiment of the invention shown in the open condition; Figure 8 is an underplan view corresponding to Figure 7;; Figure 9 is a vertical central cross-section through the clip shown in Figure 7; Figure 10 is a side elevation of a clip according to Figures 7-9 but showing the space containing the filter pad closed; and Figure 11 is a cross-section on the line A-A of Figure 8.

Modern ostomy bags are made of two superposed sheets of plastics material, welded around their edges, and one example of such a bag is illustrated in British Patent Specification 1 7 204. The walls of the bag are of synthetic plastics material, and are attached together by a weld seam around the bag. A fold-over filter clip according to the invention is folded over an upper region of the bag. This clip has a first member and a second member. The first member carries a spike and this spike is surrounded by an adhesive on an inner surface of the first member. In its folded-over position the clip may be pinched or pressed onto the top of the ostomy bag in such a way that the spike punctures both bag walls.

The filter clip illustrated in Figures 1-5 includes a first member 10 hinged to a second member 12 by a hinge 14. The first member 10 carries (or is integral with) a spike 16 which extends from a flat surface 18. The second member 12 has a peripheral wall 20 defining a space 22 which is the shape of a flat cylindrical disc. The wall 20 has an integral flange 24 which presents an upwardly-facing flat surface 26. The space 22 is bounded by a base wall 28 which may be integral with the wall 20 or may be a removable plate which is a push fit into the second member. The wall or plate 28 has a series of cut outs or holes 30 around its outer portion. The function of these holes or cut outs is to allow exit of filtered gases from a disc-shaped filter pad which is placed in the space 22.Such a pad may be a "Celanese" felt pad impregnated with activated carbon or other gas-adsorbing material, preferably in fine particulate form.

The flat surface 26 and the upper surface 34 of the pad 32 (shown dotted only in Figure 4) is covered (except for a central hole 35) with a layer 36 of latex adhesive which has on its top surface (as seen in Figures 3 and 4) a layer of strippable protective paper or film, which may for example be silicone treated to permit ready release.

The flat surface 11 of the member 10 surrounding the spike is similarly covered. The adhesive and strippable layer covering flat surface 11 may be contiguous with the adhesive and strippable layer covering the surfaces 26 and 34.

In use, the user strips the protective layer from the adhesive, and folds the clip over the top edge of an ostomy bag in the manner illustrated in Figure 5. The spike 16 puctures both bag walls, and the first member 10 is attached to the outer surface of one bag wall by the adhesive which entirely surrounds the spike. Consequently any gases which may escape through the spike hole cannot escape further because of the circular area of adhesive attaching the said one bag wall to the surface 11 of the member 10. Gases can, however, exit through the hole punched by the spike 16 in the other bag wall, as the circular area 35 is free of adhesive, so exposing a central region of the disc shaped filter pad 32.The gases then pass into the centre of the pad 32 and move radially outwardly therein to the exit holes 30, and in so doing are filtered and deodorised by the action of the activated carbon or like material of the pad 32. In this way, a relatively lengthy path for escape and filtering of flatus gases is achieved.

In the embodiment of the invention which employs a base wall 28 integral with the wall 20 and the flange 24, the clip can be made in a single moulding operation, the disc filter pad can then be inserted into the space 22 and one single further operation suffices to apply the strippable layer already cut to shape and already coated with adhesive.

In the embodiment of the invention which employs a snap-fitted removable plate 28 to provide the base wall of the space 22, the parts 10, 12, 1 6, 20, 24 are integrally moulded, the adhesive and strippable layer are applied thereto with the latter layer lowermost, the disc filter pad is dropped into the space 22 and the plate 28 is snap fitted to hold the pad 32 within the second member 12.

In either embodiment, the manufacture and assembly of the filter clip is simple and relatively inexpensive, and in operation the adhesive sealing of the clip surfaces to the outside of the bag walls ensures that there is no exit path available for flatus gases that does not involve a lengthy passage through the filter material. The provision of a spike so that the user automatically punctures the bag correctly as he or she applies the clip and then in the same movement of the fingers achieves an adhesive seal as described, is a particularly important and useful feature for wearers who are old or infirm and find difficulty in manipulation.

It has been found that elderly patients or patients in poor health find it difficult to satisfactorily apply a conventional patch-filter such as that shown in British Patent 1 550 960 or British Patent 1 462 492.

Figure 6 shows an ostomy bag 70 of synthetic plastics material with a filter clip 72 according to the invention attached thereto. The ostomy bag is conventional except that its front and rear walls are welded together with arcuate welds 74. These welds make up a curved weld joint joining the walls and whose two ends extend to the top edge weld seam 76 of the bag. At least one gap (in fact two gaps 78 are shown) is provided between the arcuate welds so that flatus gases can enter the space bounded by the curved weld joint, the edge weld, and the front and rear walls of the bag. A bag side coupling element is shown at 82. For further details of this, see for example British Patent Specification No. 1 586 824 or British Patent Application 82-07172. In use of the filter shown in Figures 1-5, the spike is used to puncture the front and rear bag walls within the space referred to. The function of the curved weld joint is to prevent faecal matter reaching the hole punched by the spike. As seen in the drawing, two gaps are provided separating three arcuate welds, but any convenient number may be used. The width of each gap 78 has dimensions chosen so that the gap offers a desired resistance to flow of gas from the lower part of the bag to the upper space. Each gap 78 defines a path which allows gas to pass from the remainder of the bag into the upper space demarcated by welds 74, but inhibits or substantially prevents faecal matter passing into the upper space. This avoids choking of the filter pad with slurry-like bag contents, and tends to prevent the bag walls collapsing towards each other.

The width of each gap 78 is preferably between about 0.1 inch (2.5 mm) and about 0.14 inch (3.6 mm) and the gaps may be spaced at equal intervals along the weld. The weld 74 need not be arcuate, it could for example define a partrectangular space.

While the invention has been described from the point of view of illustrative embodiments thereof, it must not be construed as limited to such embodiments. It is regarded as extending to any fold-over filter clip having a pad of filter material on one limb and a spike which can puncture the walls of an ostomy bag on the other limb.

An alternative embodiment of the invention is shown in Figures 7-11. The filter clip shown therein is similar in principle to that shown in Figures 1-5. It has a first member 90 joined by an integral hinge 92 to a second member 94 which defines a space 96 to receive a filter pad 97 and a controlled porosity layer 99. The second member 94 is joined by an integral hinge 98 to a lid 100 which has a number of slots 102 in its periphery. As shown, the second member and lid are circular in shape, but of course this is not essential; they could, for example, be oval. The lid has a rim portion 104 diametrically opposite to the hinge 98 which co-operates with a catch 106 formed by an inclined surface on the inner rim of the second member 94.Due to this construction, the lid can be snapped into its closed position, once the filter 97 and the controlled porosity layer 99 have been placed in the space 96 during assembly of the filter clip. The layer 99 may be adhesively sealed at its rim to the adjacent wall 101 of the second member 94. The first member 90 has a spike 108 and a layer of adhesive 110 covered by a strippable protective layer 112 covers surfaces 114,116 of the first and second members in a similar manner, and for a similar purpose, to the corresponding layers described with reference to Figures 1-5. A hole 118 is provided in the upper wall 120 of the second member 94 to allow the flatus gases to pass into the central region of the filter pad.The filtering action, and the manner of application to an ostomy bag, of this embodiment of the invention are in essence the same as those of the embodiment shown in Figures 1-5, apart from the advantages provided by the controlled porosity layer 99.

The presently-preferred filter pad is made by cutting discs from a sheet of filter medium known as "BONDINA" activated carbon filter No. S.442.

Tests on one inch diameter discs of this filter material have shown it to be highly successful in deodorising a gas mixture consisting of 20% methane, 25 p.p.m. HS and the balance nitrogen.

The presently-preferred controlled porosity layer is known as "BONDINA" non-woven viscose medical tape, No. T.1562F. This material may have a thickness of 0.23 mm and a weight of 55 g/m2. It is permeable to air at 480 I/minute, 0.5 m.bar DIN 53 887-77.

While there has been described, in connection with Figure 6, the use of a bag of a particular design with a fold over filter clip according to the present invention, it is important to note that a clip according to the invention can be used with any of the designs of ostomy currently on the market.

Claims (15)

1. A fold-over filter clip for use on an ostomy bag, comprising first and second members joined together or hinged together and made from a material which can be readily bent by human finger pressure, one of these members (the first) having a bag-puncturing spike extending outwardly from a substantially flat surface thereon and having an adhesive covered by a strippable protective layer on the said surface, and the other (the second) of the members having a substantially flat filter pad of open-cell material carrying a gas-adsorber, e.g. activated carbon, disposed in a space in the second member complementary in shape to the pad, one surface of the pad being covered with an adhesive which is in turn covered by a strippable protective layer and the other surface of the pad being in engagement with a base wall.

2. A clip according to claim 1 in which the two hinged or joined members are moulded with an integral hinge from a mouldable synthetic plastics material.

3. A clip according to claim 2 in which the said material is polypropylene.

4. A clip according to claim 1 in which the two members are made of aluminium or an aluminium alloy.

5. A clip according to any preceding claim in which the spike is integral with the first plate member.

6. A clip according to any one of claims 1 in which the spike is secured to the first member.

7. A clip according to claim 2 in which the said material is nylon six.

8. A clip according to any preceding claim in which the second member defines a disc-shaped space for receiving the filter pad, the space being partly bounded by a base wall.

9. A clip according to claim 8 in which the base wall is pivoted to the remainder of the second member as an integral hinge.

10. A clip according to claim 8 in which the base wall is removable.

11. A clip according to claim 10 in which the base wall is a push fit or a snap fit into the remaining part of the second member.

12. A fold-over filter for use on an ostomy bag, comprising first and second substantially flat plate members joined together or hinged together and made from a material which can be readily bent by human finger pressure, one of these members having a bag-puncturing spike extending substantially normally therefrom and having an adhesive covered by a strippable protective layer thereon, and the other (the second) of the members having a substantially flat pad of open cell material carrying activated carbon, the pad being covered with an adhesive in turn covered by a strippable protective layer.

13. A clip substantially as herein described with reference to and as illustrated in Figures 7-11 1 of the accompanying drawings.

14. A fold-over filter clip for use on an ostomy bag according to any one of claims 1-12 in which the pad is overlaid by a controlled porosity layer.

15. A clip according to claim 14 in which the controlled porosity layer has a permeability to air of from 450 to 510 1/my, 0.5 m.bar, measured according to DIN 53 887-77.