NL2005450A

NL2005450A - Method of manufacturing an ostomy bag and ostomy bag manufactured with the method.

Info

Publication number: NL2005450A
Application number: NL2005450A
Authority: NL
Inventors: Timothy Kenneth Thorndale; Rory James Maxwell Smith; Paul Stephen Bird; Padraig Gerard Troy
Original assignee: Welland Medical Ltd
Priority date: 2008-02-27
Filing date: 2010-10-04
Publication date: 2010-12-15
Also published as: AU2009200789A1; GB0803558D0; IT1394206B1; ITMI20090271A1; NL2005450C2; GB2457763B; GB2457763A; NL2002556C2; NL2002556A1; AU2009200789B2

Abstract

An ostomy bag with a filter means 1 attached to a first wall 13 of the bag is disclosed, wherein the filter means comprises a filtration layer 3 formed of a deodorising material, such as activated charcoal, layered with at least one layer of gas-impermeable material 9, 11 to leave at least a part of a lateral edge of the deodorising material uncovered. At least one laser-cut aperture (15) passes through the first wall of the bag to expose the deodorising material. The material which surrounds the aperture has a substantially uniform thickness. A method of manufacturing an ostomy bag incorporating a filter means is also disclosed (Fig.2).

Description

Method of manufacturing an ostomy bag and ostomy bag manufactured with the method

The present invention relates to a method of manufacturing an ostomy bag having an odour adsorbing or deodorizing filter incorporated into the ostomy bag. The invention further relates to an ostomy bag manufactured with the method according to the invention.

Existing odour absorbing or adsorbing filters for an ostomy bag allow flatus gas to be released through an activated charcoal layer, which helps to remove faecal odour. Odour adsorbing filters are discussed in the Applicant's British Patent GB2296660, wherein the filter is in the form of a disc positioned on the inside of one wall of an ostomy bag. Filters are also discussed in the Applicant's US Patent Publication No. 2006/0107642. The carbon filtration layer is sandwiched between two layers of a thermofusible plastic film to allow the filter to be heat welded to the wall of the ostomy bag. To allow gas to flow out of the filtration layer of the filter an exit aperture is punched into the filter by a knife-edge incorporated with the welding tool. The exit aperture is punched through the bag wall and through one of the film layers. Thus, gas can flow into the filtration layer of the filter around the perimeter of the disc and out of the centre of the filter via the exit aperture.

It has been found that by using a knife edge, there is a risk that the exit aperture will be cut through both film layers and through the filter itself. Gas will flow too quickly out of the bag, will flow through the filter material axially rather than radially and will not be deodourised. It has also been found that, over time, plastic material builds up on the knife edge and the knife edge becomes ineffective at punching out an exit aperture. The knife edge also becomes blunt with use. Without an exit aperture through both the bag wall and the plastic film, gas is unable to exit the filtration layer. The gas will be unable to exit the bag and also the gas will not be deodoursied. Gas will be produced and enter the bag more quickly than it can escape. This will cause the bag to "balloon" and make the wearer uncomfortable and the bag less discretely hidden on the wearer's body.

Existing practice involves monitoring the knife edge to detect when the knife needs cleaning and/or re-sharpening. However, such monitoring is time consuming and it remains difficult to monitor the exit apertures such that each aperture is uniform. Furthermore, by using a knife edge to form an exit aperture the material surrounding the exit aperture is not removed. The material is moved away from the exit aperture by the knife edge but can move back after cutting and make the exit aperture smaller and less effective than intended. For example, the material can be moved away from the exit aperture but still remain around the aperture edge, which causes thickening of the material surrounding the aperture. Such a less effective aperture obstructs the flow of gas and again results in the problem of "ballooning" of the bag.

It is also understood that a central exit aperture provides the most effective balance between filtering and flow rate of the gas passing through the filter. The path length travelled by the gas through the filter is maximised with a central exit aperture and thus, the deodourising action of the filter is also maximised. However, it has been found that when the exit aperture is punched by a knife edge it is difficult to ensure that the exit aperture is exactly central to the filter disc. If the exit aperture is not central within the filter then the gas will travel along radii of different length through the filter. If the gas travels a greater distance through the filter more odour will be removed, but flow rate will be decreased. If the gas travels a lesser distance through the filter less odour will be removed, but flow rate will be increased.

The present invention sets out to provide an improved odour adsorbing filter which alleviates the problems described above by enhancing airflow and providing a consistent balance between the odour adsorbency of the filter and the flow rate of gas through the filter.

In one aspect, the invention provides an ostomy bag with a filter means attached to a first wall of the ostomy bag, wherein the filter means comprises a filtration layer formed of a deodorising material layered with at least one layer of gas-impermeable material leaving at least a part of a lateral edge of the deodorising material uncovered, at least one laser-cut aperture passing through the first wall of the ostomy bag to expose the deodorising material, characterised in that the material surrounding the aperture has a substantially uniform thickness.

Within the context of this specification the word "comprises" is taken to mean "includes, among other things". It is not intended to be construed as "consists of only".

The "thickness" of the material surrounding the aperture is taken to be the length of the material which is perpendicular to the plane of the layers of the filtration layer. This is usually the smallest of the three dimensions of the filtration layer.

When the thickness of the material surrounding the aperture is substantially uniform along its length enhanced airflow is provided through the filter means. Without an increased thickness or "bunching" of the material surrounding the aperture a "clean", clear path is provided to expose the deodorising material and allow gas to exit.

By "substantially uniform" it is to be understood that the thickness of the material through which the aperture passes varies by no more than about 9% of its average thickness along the length of the material.

Within this specification, the term "about" is interpreted to mean optionally ±20%, preferably optionally ±10%, more preferably optionally ±5%.

A laser-cut aperture provides enhanced airflow through the filter means because a clear path through the first layer of gas-impermeable material and through the first wall of the ostomy bag is provided to allow gas to exit. The radiation vaporises, and so removes, the material of the bag wall and the gas-impermeable layer to allow gas to exit the filter more easily. The size and dimensions of the aperture can be selected such that the maximum amount of odour is removed from the gas whilst the flow rate is sufficient to prevent the bag "ballooning".

Preferably, the filter means is disc shaped.

A disc-shaped filter means provides improved deodorising action with minimal discomfort to a wearer of the ostomy bag.

Preferably the disc-shaped filter means has a radius of between 5 and 25mm.

Preferably, the at least one laser cut aperture has a diameter of between 1 and 40mm.

Preferably, the at least one laser cut aperture is positioned in the centre of the disc-shaped filter means.

A central exit aperture means that the path length travelled through the filter means between the perimeter of the disc-shaped filter and the exit aperture is maximised and the deodorising action is constant for all gas passing through the filter.

Preferably, the deodorising material comprises an activated carbon fabric or an activated carbon material incorporated into a second material such as foam, fabric or paper.

Preferably, the ostomy bag comprises two or more apertures.

Preferably, the ostomy bag comprises at least one ring concentric with the disc-shaped filter means.

More preferably, the ostomy bag comprises two rings concentric with the disc-shaped filter means.

Optionally, the at least one aperture is an arc, or is triangular, square, rectangular, elliptical or shaped as a letter/s of the alphabet.

Preferably, the filtration layer is sandwiched between two layers of gas-impermeable material.

In a second aspect, the present invention provides an ostomy bag with a filter means attached to a first wall of the ostomy bag, wherein the filter means comprises, a filtration layer formed of a deodorising material layered with at least one layer of gas-impermeable material leaving at least a part of a lateral edge of the deodorising material uncovered, and characterised by at least two apertures passing through the first wall of the ostomy bag to expose at least a part of the planar surface of the deodorising material.

Preferably, the filter means is disc shaped.

Preferably the disc-shaped filter means has a radius of between 5 and 25mm.

Optionally, the at least two apertures comprise at least one ring concentric with the disc-shaped filter means.

Preferably, the at least two apertures comprises two rings concentric with the disc-shaped filter means.

Preferably, the at least one concentric ring aperture has a diameter of between 1 and 40mm.

Preferably, wherein the disc shaped filter has a 25mm diameter the width of the outer concentric ring is no more than about 5mm.

The diameter of the outer concentric ring is critical to ensure that a sufficient path length is maintained for effective deodorisation.

Optionally, the at least two apertures are positioned inwardly of the outer circumference of the disc each at an equal radius from the disc's centre.

Preferably, the at least two apertures are circular.

Optionally, the at least two apertures are semi-circular.

Optionally, the at least two apertures are each any of an arc, a triangle, a square, a rectangle, an ellipse or shaped as a letter/s of the alphabet.

The aperture can be of any shape, which allows the aperture to be used to brand the product, for example, with a company name or logo.

In a third aspect, the present invention provides a method of manufacturing an ostomy bag incorporating a filter means comprising the steps of; forming an ostomy bag by heat welding a first and second wall together; forming a filter means by layering a deodorising material with at least one layer of gas-impermeable material leaving at least a part of a lateral edge of the deodorising material uncovered; attaching the filter means to a first wall of the ostomy bag, characterised by the step of remote cutting at least one aperture through the first wall of the ostomy bag to expose the deodorising material.

By "remote cutting" it is to be understood that cutting of the at least one aperture does not involve invasive contact between the cutting means and the first wall of the ostomy bag or the gas-impermeable material.

Preferably, remote cutting is carried out by a remote cutting means at a distance of between 1mm and 500mm from the first wall of the ostomy bag.

Preferably, cutting is carried out using a laser.

Preferably, the laser is a gas laser such as a carbon dioxide laser.

Optionally, the laser is a solid-state laser.

Optionally, the laser is a semiconductor diode laser.

Remote cutting of an exit aperture through the filter means allows the size and dimensions of the exit aperture to be accurately controlled. For example, a laser vaporises and so removes the material of the bag wall and the gas-impermeable layer to allow gas to exit the filter more easily. The position of the aperture can also be accurately controlled by laser cutting.

Preferably, the laser beam is focussed using a lens.

Preferably, the filter means is attached to the first wall of the ostomy bag by heat welding.

In a fourth aspect, the present invention provides an ostomy bag manufactured in accordance with the above-described method.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings, in which:-

Figure 1 is a cross sectional view of a filter attached to the wall of an ostomy bag and constructed in accordance with the present invention;

Figure 2 is a schematic view of the machine used in the manufacture of an ostomy bag constructed in accordance with the present invention;

Figures 3a to 3d are views from above of different aperture configurations of the filter in accordance with the present invention;

Figure 4 is a plan view of the test rig used for testing the efficiency of the filter as described in Example 2.

Referring to Figure 1, the filter 1 consists of a filtration layer 3 composed of a deodorising material such as activated charcoal. The filtration layer 3 is a mixture of activated charcoal and impregnated activated carbon bound to the surface of a polyester non-woven fabric. The filtration layer 3 is a disc having a diameter of between 10 and 30mm. The filtration layer 3 is sandwiched between two gas-permeable layers 5, 7, leaving the lateral edges of the filtration layer uncovered. The layers 5, 7 are formed of a net-like thermofusible web based on a thermoplastic polymer such as Ethylene Vinyl Acetate (EVA). Laminated on the outer surface of each of the thermofusible web film layers 5, 7 is a co-extruded film layer 9, 11. The film layers 9, 11 are a material composed of a layer of polyvinylidene chloride (PVdC) between layers of a material such as Ethylene Vinyl Acetate (EVA) or Polyethylene (PE). Alternatively, PVdC may be substituted by Ethylene-Vinyl Alcohol (EVOH) or Nylon. The layered material may also include tie-layers between the layers of PVdC, EVOH or Nylon and EVA or PE. Such tie layers may also be Ethylene Vinyl Acetate (EVA). Thus, the filter 1 is a multilayered structure with an odour barrier layer and outer polyolefin layers. It is possible that the filter 1 is layered on only one surface with a thermofusible web 5 and a film layer 9. In such an embodiment, the second surface of the filter 1 is fixed directly to the wall 13 of the ostomy bag.

During manufacture of an ostomy bag with a filter, the filter 1 is positioned on the inside of one wall 13 of an ostomy bag. The wall 13 of the ostomy bag is composed of a film of thermoplastic polymer. As previously described with respect to film layers 9, 11 the film of the ostomy bag wall 13 is composed of a layer of polyvinylidene chloride (PVdC) between layers of a material such as Ethylene Vinyl Acetate (EVA) or Polyethylene (PE). Alternatively, PVdC may be substituted by Ethylene-Vinyl Alcohol (EVOH) or Nylon. Such a film is available from Sealed Air Corporation or The Dow Chemical Company. The filter 1 is heat sealed to the wall 13 of the ostomy bag using a flat welding tool.

Referring to Figure 2, two rolls of thermoplastic polymer film A (as previously described) are fed into the ostomy bag manufacturing apparatus together with two rolls of non-woven material B. The bodyside non-woven material B is marked by printing means C with appropriate markings to enable a user to position the finished bag. A bodyside mounting wafer or attachment means (not shown) is then welded by welding means D to a bodyside surface of film A. An aperture is punched by cutting means E through the bodyside wall of the ostomy bag. The aperture is cut through the polymer film A, the non-woven material B and the attachment means. In use this aperture is placed around a user's stoma.

Referring to F and G of Figure 2, the bagside polymer film A and non-woven material B are brought together and a filter 1 is welded by welding means F to the inner surface of film A. A laser G cuts exit aperture 15 through the film layer A and non-woven material B of the bag wall 13 and through one of the film layers 7 of the filter 1. The laser G can be a semiconductor diode laser, a solid-state laser, a gas laser or any other suitable type. A suitable laser can be sourced from Synrad Inc. For example, a carbon dioxide laser is used operating at a wavelength of 9.3 pm or 10.6pm with a power range of between 10W and 400W. The laser G is focussed by a lens (not shown) and is positioned to vaporise the material of the bag wall 13 and the film layer 7. The focused laser beam heats the material surface of the bag wall 13 and the film layer 7. The exit aperture 15 can be created by either moving the laser beam across the surface of the stationary material or moving the material whilst the laser beam remains stationary. A combination of these two options is also possible.

The two walls A, B of the ostomy bag are welded together by welding means H to form the outline of the ostomy bag before the outline of the ostomy bag is cut by cutting means I.

An alternative position for laser G is shown at J, whereby it is possible for the exit aperture 15 to be cut through the bag wall 13 and into the filter 1 after the bag itself has been cut from the film A and non-woven material B of the bag walls.

The exit aperture 15 is shown in Figure 1 to be a circular aperture positioned centrally to the filter Alternative embodiments of the present invention are shown in the different aperture configurations of Figures 3a to 3d and discussed below with respect to testing of the filter 1.

In use, the ostomy bag is attached to a patient's body. The ostomy bag can be a closed bag or, alternatively, a drainable bag. Gas released from the patient's body enters the ostomy bag and flows into the filtration layer 3 around the perimeter of the filter 1 and out of the centre of the filter 1 via the exit aperture 15.

The above described embodiments have been given by way of example only, and the skilled reader will naturally appreciate that many variations could be made thereto without departing from the scope of the present invention. For example, the one or more apertures 15 can be of any desired configuration. It is envisaged that the aperture 15 configuration can also be used to indicate the brand of the ostomy bag. As shown in Figure 3b lettering can be laser cut into the filter 1.

Testing

Tests were carried out to assess flow rates and deodorising capabilities of the following filters:

[Table 1]

Figures 3a-c illustrate the configurations of exit apertures that were tested. Figure 3a shows the circular vent configuration of samples 1, 2 and 3. Figure 3b shows the configuration of sample 4, with a 'W-shaped' aperture 15 within a ring-shaped aperture 15 that is concentric with the filter 1. Figure 3c shows the configuration of sample 5, which comprises an eight pointed star. Figure 3d shows an alternative embodiment wherein eight apertures 15 of equal size positioned inwardly of the outer circumference of the disc-shaped filter 1. Each aperture 15 is at an equal radius from the disc's centre.

Standard filters obtained from Purification Products Limited were used for all of the tests, which consist of a mixture of activated and impregnated activated carbon bound to the surface of a non-compacted polyester non-woven fabric and laminated between two gas impermeable film layers. The filters were of a 25mm diameter. Such a "non-compacted" or "open" fabric is referred to by the manufacturer as a "lofty" material. It has been found that the present invention offers much improved flow rate control for such materials.

Example 1 - Flow Rate Test

The purpose of this evaluation was to assess the filter permeabilities for various diameters and configurations of exit apertures, which were laser cut into the filter. Pouches were inflated at a pressure of lOmbar on a test rig and the flow rate at lOmbar through the filter was recorded with a flow meter.

[Table 2] - Results of Flow Rate Test

This test indicated an air flow through the laser cut exit aperture of between 107 and 190cc/min, which is much enhanced from the flow through existing knife-cut filters, which is in the region of 60 to 80 cc/min.

Example 2 - Hydrogen Sulphide Deodorisation Test

The purpose of this evaluation was to assess the deodorising capabilities of filters with various diameters and configurations of exit apertures, which were laser-cut into the filters. The test for odour breakthrough was conducted in accordance with BS 7127 "Method for Determining Efficiency of a Filter". The reagent used is a gas mixture containing a volume fraction of (30±5) (V/V) hydrogen sulphide in a mixture of nitrogen of volume fraction 0.80± 0.1 x 10'6 (V/V) and methane of volume fraction 0.20 ± 0.1 x 10'6 (V/V). The test rig comprises a gas cylinder 20 and pressure regulator 21, flow regulator 22, filter housing 23, electronic gas detector 25 and graduated hydrogen sulphide tube 26 as shown in Figure 4.

Referring to Figure 4, the flow regulator 22 can control flow rates of up to 250mL/min. The electronic hydrogen sulphide detector 25 can detect a volume fraction of 0.5 x 10'6 (V/V) hydrogen sulphide. The graduated hydrogen sulphide detector tube 26 may also be a wide-range electronic gas detector capable of determining a volume fraction of 20 xlO'5 (V/V) to 50 xlO'5 (V/V) hydrogen sulphide. A stopwatch or similar timing device is also used.

After checking that the filter housing 23 is empty, the electronic hydrogen sulphide detector 25 is disconnected. Approximately 1 litre of the gas mixture referred to above is passed through the rig to purge the air from the system and then the hydrogen sulphide detector tube 26 is connected. The pressure regulator 21 is set to 1 ± 0.1 bar and the flow regulator 22 is set to 250±10mL/min. The stop watch is started and the time is recorded for the detector tube 26 to reach each graduation until it is completely saturated. If the volume of concentration of hydrogen sulphide falls within the range of volume fractions 25 x 10'6 (V/V) to 35 x 10"6 (V/V) then the filter 24 is mounted such that gas will flow through the filter 24 as intended in normal use. The hydrogen sulphide detector tube 26 is then disconnected and the electronic hydrogen sulphide detector 25 is switched on and zeroed. The pressure regulator 21 is again set at 1 ± 0.1 bar and the flow regulator 22 is set to 250±10ml7min. The stop watch is started and the time taken until the hydrogen sulphide detector 25 registers a volume fraction of 1 x 10'6 (V/V) of hydrogen sulphide is recorded.

[Table 3] - Results of Hydrogen Sulphide Deodorisation Test

This test indicated that the improvement in air flow through the laser cut filters is not at the expense of deodorisation.

It was noted that sample 4 with an annular vent around a 'W' shaped aperture offered an improved flow rate without any reduction in deodorising capability.

Claims

A method for manufacturing a stoma bag, which has a filtering means, comprising the steps of: forming a stoma bag by heat-welding a first and a second wall together; forming a filtering means by overlaying a deodorizing material and at least one layer of gas-impervious material, wherein at least a portion of a lateral edge of the deodorizing material remains uncovered; attaching the filtering means to a first wall of the stoma bag, characterized by the step of remotely cutting at least one opening through the first wall of the stoma bag to expose the deodorizing material, wherein the remote cutting is performed by a cutting means at a distance between 1 and 500 mm from the first wall of the stoma bag and using a laser.

A method for manufacturing a stoma bag according to any of the preceding claims, wherein the laser beam is focused using at least one lens.

The method for manufacturing a stoma bag according to claim 2, wherein the laser beam is focused using a series of lenses.

A method for manufacturing a stoma bag according to any one of the preceding claims, wherein the laser beam is focused using at least one mirror.

A method for manufacturing a stoma bag according to any one of the preceding claims, wherein the filtering means is attached to the first wall of the stoma bag by heat welding.

A method for manufacturing a stoma bag according to any one of claims 1 to 5, wherein the laser is a gas laser, such as a carbon dioxide laser.

The method for manufacturing a stoma bag according to any of claims 1 to 5, wherein the laser is a solid state laser.

A method for manufacturing a stoma bag according to any one of claims 1 to 5, wherein the laser is a semiconductor diode laser.

A stoma bag made according to the method according to one of the preceding claims.