GB2296660A

GB2296660A - Flatus filter for ostomy bag etc.

Info

Publication number: GB2296660A
Application number: GB9418395A
Authority: GB
Inventors: Nicholas Steven Shelley; Rory James Maxwell Smith
Original assignee: Welland Medical Ltd
Current assignee: Welland Medical Ltd
Priority date: 1994-09-13
Filing date: 1994-09-13
Publication date: 1996-07-10
Anticipated expiration: 2014-09-13
Also published as: GB2296660B; GB9418395D0

Abstract

A bodily waste collection bag includes a filtering element 14 overlying a hole 12 in a wall 10 of the bag, the element (a) comprising a layer of deodorising material 16 and a gas impermeable layer 18 covering the top surface thereof while leaving at least part of a lateral edge uncovered and (b) being enclosed within a pocket defined by said wall and by a layer of gas permeable, water impermeable material 20 which has a mean pore size of 4-45 mu m and an air permeability at 10cm. H2O pressure of 80-500 cc/cm<2>/min. The pore size of said material may be greater in the body of such material than at its surface to improve resistance to clogging. Layer 16 may be of activated charcoal fabric, layer 18 of polyethylene film and layer 20 of high molecular weight polyurethane. <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 (hereinafter referred to as "bags").

The provision of filters in such bags is known per se, and is shown in documents such as GB 2215608 and GB 2221854. The present invention seeks to provide a filter for such a bag which is equally or more flexible and unobtrusive as known bags, whilst being less susceptible to contamination and/or clogging by collected material, and/or simpler to manufacture.

To this end, it provides a bodily waste collection bag, having a filter comprising: a filtering element consisting of a layer of deodorising material, a first surface of which is at least partly covered with a layer of gas impermeable material, at least part of a lateral edge of the deodorising material layer being uncovered; the filtering element being within a closed pocket defined by a wall of the bag and by a layer of gas permeable water impermeable material affixed to at least the wall of the bag, the first surface of the filtering element facing the gas permeable water impermeable material; wherein the gas permeable water impermeable material has a mean pore size of between 4 and 45 um, and an air permeability at 10cm H20 pressure of between 80 and 500 cc/cm2/min.

It has been found that the filter is particularly resistant to clogging if the pore size of the gas permeable water impermeable material is greater in the body of the material than at its surface, and therefore this arrangement is preferred. In this case, the pore size limits given refer to the pore size in the body of the material.

A more effective filtering action is obtained if the filtering element is affixed to the wall of the bag, although the same effect may be achievable by providing a snug pocket.

Particularly preferred ranges of the pore size are 6 to 35us, more preferably 8 to 25um, and even more preferably 12 to 18Fun.

Preferred values of the air permeability are 200 to 400, more preferably 200 to 300, and particularly preferred is 230 to 270cc/cm2/min, measured at the same water pressure.

A suitable thickness for the gas permeable water impermeable material is 0.5 to 1.2 mm.

A suitable weight for the gas permeable water impermeable material is 130 to 310 g/m2.

Preferably, the gas permeable water impermeable material has an elongation at break of at least 200%.

A suitable volume porosity for the gas permeable water impermeable material is 77 to 83%.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front view of a filter according to the present invention attached to the surface of the bag, and Figure 2 is a section on II-II of Figure 1.

Referring to Figures 1 and 2, these show a wall of a bag 10, in which is formed a small hole 12. A filtering element 14 overlies the hole 12, and in this embodiment is bonded to the bag wall 10 by welding region 15. The element is constructed of a layer of deodorising material 16 adjacent the wall 10, and a gas impermeable layer 18 covering the top surface of the deodorising material layer 16, but leaving the lateral edges uncovered. In this embodiment, the deodorising material 16 is of an activated charcoal fabric. This is produced by heating in a controlled atmosphere, and is obtainable from Charcoal Cloth International Ltd, Houghton Le Spring, Tyne & Wear, UK. The gas impermeable layer is a polyethylene film layer.

A layer of gas permeable water impermeable material 20 is welded at joints 22 to the bag 10 so as to form a pocket enclosing the filtering element 14. In this embodiment, there is no direct bond between the layer 20 and a filter element 14, but this is not essential. The layer 20 is formed of a high molecular weight polyurethane, and is porous and hydrophobic. A suitable material is available under the trade mark Kyroderm F from Porvair Filtronics Ltd of Sheperton, Middlesex, UK. Typical properties of Kyroderm F are set out in Table 1. As supplied, the material has a natural "skin" effect, such that the pores at the surface are smaller than those within the body of the material.

Table 1

Thickness mm 0.5 to 1.2 I Weight g/m2 130 to 310 Tensile strength Kg/cm 0.9 min Elongation at Break % 200 min Air permeability cc/cm2/min e 250 min 10cm H2O pressure Mean pore size p 15 Volume porosity % 77-83 Temperature range DC -20 to 150 It will be apparent to the skilled person that various modifications and alterations can be made to the filter shown in the enclosed drawings, without departing from the principles underlined in the present invention. For example, the filtering element 14 could be welded to the layer 20, or where welds are described, suitable hot weld adhesive can be substituted. Furthermore, it is possible to omit hole 12, and supply the bag unvented. A user would then make a suitable hole, eg by using a pin.

Claims

1. A bodily waste collection bag, having a filter comprising: a filtering element consisting of a layer of deodorising material, a first surface of which is at least partly covered with a layer of gas impermeable material, at least part of a lateral edge of the deodorising material layer being uncovered; the filtering element being within a closed pocket defined by a wall of the bag and by a layer of gas permeable water impermeable material affixed to at least the wall of the bag, the first surface of the filtering element facing the gas permeable water impermeable material; wherein the gas permeable water impermeable material has a mean pore size of between 4 and 45 urn, and an air permeability at 10cm H20 pressure of between 80 and 500 cc/cm2/min.

2. A bag according to claim 1 wherein the pore size of the gas permeable water impermeable material is greater in the body of the material than at its surface.

3. A bag according to claim 1 or claim 2 wherein the filtering element is affixed to the wall of the bag.

4. A bag according to any preceding claim wherein the pore size is between 6 to 35us, more preferably 8 to 25um, even more preferably 12 to 18urn.

5. A bag according to any preceding claim wherein the air permeability is between 200 to 400, preferably 200 to 300, more preferrably 230 to 270cc/cm2/min, measured at the same water pressure.

6. A bag according to any preceding claim wherein the thickness of the gas permeable water impermeable material is 0.5 to 1.2 mm.

7. A bag according to any preceding claim wherein the weight of the gas permeable water impermeable material is 130 to 310 g/m2.

8. A bag according to any preceding claim wherein the gas permeable water impermeable material has an elongation at break of at least 200%.

9. A bag according to any preceding claim wherein the volume porosity of the gas permeable water impermeable material is 77 to 83%.

10. A bodily waste collection bag substantially as herein described with reference to the accompanying figures.