GB2555769A

GB2555769A - In-line tester with integral colour chart

Info

Publication number: GB2555769A
Application number: GB1611784.8A
Authority: GB
Inventors: Gallagher George
Original assignee: Aspirate N Go Ltd
Current assignee: Aspirate N Go Ltd
Priority date: 2016-07-06
Filing date: 2016-07-06
Publication date: 2018-05-16
Also published as: GB201611784D0

Abstract

In-line tester 10 comprises chamber 14 between inlet 20 and outlet 22. Chamber 14 comprises first and second interconnected parts 16, 18, having formations 36, 50 which clamp (and perhaps seal) porous or perforated element 38, which comprises a colorimetric substance, around its periphery within the chamber between the inlet and outlet. First part 16, comprising the inlet, is manufactured from a transparent material. The first and/or second part has flange portion 32, which comprises colour chart 41 which can be viewed through the first part and compared with element 38. Element 38 may permit air or gases to pass but not liquids (e.g. aspirated liquid), and may form part of a self-closing valve that allows dry fluids to enter the chamber but closes when wetted. The pores or perforations, perhaps in a hydrophobic layer, may close when wetted, maybe by water droplets repelled by the hydrophobic surface.

Description

₍₁₂,UK Patent Application _<19)GB ,,,,2555769 ,η,Α (43) Date of A Publication 16.05.2018

(21) Application No:	1611784.8	(51) INT CL:
G01N 31/22 (2006.01)	G01N 33/48 (2006.01)
(22) Date of Filing:	06.07.2016	(56) Documents Cited:
(71) Applicant(s): Aspirate N Go Ltd IC1,131 Mount Pleasant, LIVERPOOL, Merseyside, L3 5TF, United Kingdom (72) Inventor(s): George Gallagher	GB 2523620 A JP 2015161656 A US 20050265895 A1 (58) Field of Search: INT CLA61B, G01N Other: EPODOC, WPI	WO 2011/157981 A1 US 6576473 B1
(74) Agent and/or Address for Service: Hutchinson IP Ltd 57 Hoghton Street, SOUTHPORT, Merseyside, PR9 0PG, United Kingdom

Title of the Invention: In-line tester with integral colour chart Abstract Title: In-line colorimetric tester with integral colour chart

In-line tester 10 comprises chamber 14 between inlet 20 and outlet 22. Chamber 14 comprises first and second interconnected parts 16, 18, having formations 36, 50 which clamp (and perhaps seal) porous or perforated element 38, which comprises a colorimetric substance, around its periphery within the chamber between the inlet and outlet. First part 16, comprising the inlet, is manufactured from a transparent material. The first and/ or second part has flange portion 32, which comprises colour chart 41 which can be viewed through the first part and compared with element 38. Element 38 may permit air or gases to pass but not liquids (e.g. aspirated liquid), and may form part of a self-closing valve that allows dry fluids to enter the chamber but closes when wetted. The pores or perforations, perhaps in a hydrophobic layer, may close when wetted, maybe by water droplets repelled by the hydrophobic surface.

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Title: In-line tester with integral colour chart

Description:

This invention relates to in-line testers of the sort typically used for testing liquids in tubes.

In-line testers are used in a variety of industrial and medical applications, and comprise a chamber containing a test strip. An in-line tester usually comprises an inlet and an outlet, to permit a fluid to flow into, and out of, the chamber and the test strip is typically interposed between the inlet and outlet such that the fluid under consideration comes into contact with the test strip as it flows through the tester. The test strip itself is often, but not always, manufactured from a liquid-absorbent material that has been impregnated, or coated, with a colorimetric substance. The colorimetric substance is selected to change colour in the presence of a target substance: one example of a commonly-used test strip being litmus paper, which changes colour depending on the pH (acidity or alkalinity) of a liquid that comes into contact with it.

One specific application of in-line testers is in nasogastric (NG) tubes, which are inserted into the body of a human or animal patient to deliver food to the patient's stomach. An NG tube is typically fed through the patient's nostril, down the patient's oesophagus and into the stomach. However, due to the bifurcation of the patient's throat into the oesophagus and trachea, it is possible, during insertion of the NG tube, to inadvertently feed its tip into the patient's bronchi or lungs; as opposed to into the patient's stomach. As such, before using an NG tube to feed a patient, it is essential to check the placement of the tip of the NG tube. This can be accomplished by aspirating a small quantity of fluid via the NG tube prior to feeding: if the aspirated liquid is acidic, this indicates the placement of the tip of the NG tube in the patient's stomach, but not otherwise. The pH test is therefore the de facto test that is used to ascertain correct NG tube placement in human or animal patients.

A pH test can be obtained by aspirating a quantity of fluid and decanting it into a container.

Then, a strip of litmus paper can be dipped into the aspirated liquid to test its acidity: the litmus paper changing colour depending on the acidity of the aspirated liquid. The colour of the litmus paper can be compared with a colour chart whose colours correspond to approximate ranges of pH values.

Carrying out a pH test in this way can be a fiddly and messy procedure, and so in-line testers, of the type described in published patent application numbers GB2523591 and GB2523620, can be used instead to reduce the amount of work involved for the attendant practitioner.

Certain embodiments of the in-line testers described in published patent application numbers

GB2523591 and GB2523620 comprise a chamber containing a disc of litmus paper, which is wetted by aspirated liquids, and which changes colour depending on the pH of the aspirated liquid. The litmus paper is visible through a transparent portion of the chamber, and can thus be compared, with relative ease, against a colour chart such as that described previously. These types of in-line testers avoid the need for an attendant practitioner to come into contact with the aspirated liquid because the aspirated liquid is contained within the test chamber.

However, despite the advantages of the in-line testers (such as those described in published patent application numbers GB2523591 and GB2523620), there still exist some practical problems that need to be addressed or overcome, as follows:

A problem associated with known in-line testers is the requirement to use them in conjunction with a colour chart, which can be easily lost. Typically, in-line testers are supplied in boxes containing a number of testers but only one or two colour charts; on in a box or package upon which the colour chart has been printed. As will be appreciated, there is potential here for loss of the colour chart, or for separation of the tester from the box/packaging meaning that a test cannot be completed until a colour chart has been found. There is also the more serious risk of using the colour chart from one batch or type of testers in conjunction with a tester of a different batch or type. Manufacturing variations, or the use of an incorrect colour chart could give rise to incorrect results (such as false positives or false negatives) with potentially life-threatening consequences.

This invention aims to provide a solution to one or more of the above problems.

Various aspects of the invention are set forth in the appended claims.

According the invention, there is provided an in-line tester comprising an inlet, an outlet and a chamber interposed between the inlet and the outlet; and a porous or perforated element comprising a colorimetric substance located within the chamber; the chamber comprising first and second interconnected parts each comprising formations that clamp a periphery of the porous or perforated element therebetween to separate the inlet from the outlet, wherein a first one of the chamber parts comprising the inlet is manufactured from a substantially transparent material, and wherein at least one of the first and second chamber parts comprises a chamber flange portion extending radially outwardly from the chamber, the said chamber flange portion comprising a colour chart arranged such that the colour chart can be compared with the porous or perforated element when viewed through the substantially transparent chamber part.

The invention advantageously provides a colour chart that is integral with, and hence, inseparable from, the in-line tester. This obviates the need to provide a separate colour chart (which may be lost) and also prevents an incorrect colour chart from being used to read off the porous or perforated element. This may also reduce packaging and labelling requirements by avoiding the need to supply an instruction leaflet comprising a colour chart with every in-line tester, or to have to keep in-line testers with their box for reading purposes. It also avoids the need to have to bring a colour chart to the in-line tester and to fiddle around trying to align the colour chart with the test strip because the colour chart and the test strip are already together and side-by-side at the point of use.

Either or both of the first and second chamber parts comprises a chamber flange portion that extends radially outwardly from the chamber. The chamber flange portion is suitably integrally formed with the respective chamber part. Suitably, the chamber flange portion comprises a substantially flat or planar surface to which the calibration chart is affixed. The calibration chart may comprise a decal affixed to the chamber flange portion.

The calibration chart suitably comprises regions of different colours, which coloured regions are suitably located at an edge of the calibration chart. This enables the coloured regions to be located directly adjacent, or slightly overlapping, the porous or perforated element, thus facilitating comparing the colour of the porous of perforated element with the different coloured regions of the calibration chart.

The colour chart is suitably arcuate, annular or donut shaped, and at least partially surrounds the porous or perforated element. In this way, the regions of different colours are all located adjacent, or overlapping, the porous or perforated element at the point of use, thereby avoiding the need to slide a colour chart relative to the porous or perforated element to obtain a reading.

The first and second chamber parts are suitably clipped, glued, welded or otherwise fixed together and there is suitably a formation, such as a flange or peripheral edge portion that clamps a periphery of the porous or perforated element between the two parts. This configuration suitably forms a seal between a periphery of the porous or perforated element and either or both of the two parts of the chamber, thereby effectively separating the inlet from the outlet by the porous or perforated element. This configuration suitably means that fluids can only pass from the inlet to the outlet through the porous or perforated element.

The porous or perforated element suitably permits air or gasses to pass through it, but inhibits and/or prevents the passage of liquids through it. In certain embodiments, the porous or perforated element comprises an air-permeable membrane, which permits air to pass through it, but not fluids.

Thus, the porous or perforated element may this conveniently provide a self-closing valve that allows dry fluids to enter the chamber, but which automatically closes-off when wetted.

The porous or perforated element is suitably manufactured of a material, such as paper, which when dry, comprises pores or perforations that allow air or gasses to pass through the material, but which, when wetted, for example by an aspirated liquid, the liquid closes the pores or perforations thereby preventing fluids (air and/or gas and/or liquid) to pass through it.

In another possible embodiment, the porous or perforated element comprises two components, namely a liquid-absorbent layer, such as paper, and a porous or perforated hydrophobic layer. The two layers are suitably conjoined to form a laminated structure. In this embodiment, the hydrophobic layer comprises pores or perforations that enable, when dry, air to pass through them (i.e. through the hydrophobic layer). However, when wetted by liquid, e.g. absorbed by the liquidabsorbent layer, the liquid is repelled from the surface of the hydrophobic layer and forced to overlie the less hydrophobic regions, that is to say, the openings of the pores or perforations. Provided the pores or perforations of the hydrophobic layer are small enough (i.e. significantly smaller than the size of a water droplet), the water that overlies the pores or perforations effectively blocks the pores or perforations, thus inhibiting or preventing the passage of air or liquid through them.

Such configurations conveniently provide a self-closing valve that permits air or gasses to pass through it when dry, but which when the wetted, self-seals to prevent fluids from passing through it.

The porous or perforated element comprises a colorimetric substance, that is to say, it is impregnated or coated with a reagent or testing chemical that changes colour upon contact with a target substance. By virtue of the substantially transparent chamber part, the porous or perforated element is visible from outside the receptacle. Suitably, the testing chemical can test for the presence of a target substance, such as any one or more of the non-exhaustive list comprising: an acid, a base (alkali), carbohydrate, glucose, sugar, blood, iron, protein, ketone, bilirubin, urobilinogen, nitrates, leukocytes, etc. Preferably, the porous or perforated element is manufactured from litmus paper, which changes colour on contact with acids or bases. Using litmus paper as the porous or perforated element of the invention conveniently enables it to be used to test for the presence of stomach acid, for example, when the invention is used as an enteral aspirator or as part of an NG tube.

The inlet or outlet suitably comprise connectors for releasably connecting items thereto, such a Luer lock connectors, bayonet-type fittings, screw threads, push-fit connectors, being either male or female. Such a configuration suitably facilitates attaching and detaching items to the in-line tester.

Suitably, the inlet comprises a connector for connecting the inlet to the connector of enteral or NG tube, such as a female Luer or female Luer-lock connector. Suitably, the outlet comprises a connector suitable for connecting it to an enteral syringe, such as a male Luer or male Luer-lock connector.

Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a front perspective view of an embodiment of an in-line tester in accordance with the invention;

Figure 2 is a rear perspective view of the embodiment of the in-line tester of Figure 1;

Figure 3 is a front perspective exploded view of the in-line tester of Figure 1;

Figure 4 is a rear perspective exploded view of the in-line tester of Figure 1;

Figure 5 is a lateral cross-section of the in-line tester of Figure 1 with its cap fitted; and

Figure 6 is a lateral cross-section of the in-line tester of Figure 1 with its cap removed.

Referring to the drawings, an in-line tester 10 in accordance with the invention comprises a main body 12 forming a chamber 14. The main body 12, and hence the chamber 14 is formed from first and second generally disc-shaped interconnected parts 16, 18, each part 16, 18 having an integrally formed spigot 20, 22, which forms an inlet or outlet of the in-line tester 10 depending on which way it is connected in use. A fluid (not shown) can enter the chamber 14 via the inlet 20 and flow out via the outlet 22, or vice-versa.

The first generally disc-shaped part 16 has a generally circular front surface 24 from which the spigot 20 extends centrally/coaxially. The spigot 20 has a connection thread, such as Luer thread 26 on its outside surface to which a tube (not shown) can be fitted using a complementary connector (not shown). The front surface 24 has peripheral flange portion 28 that surrounds a central portion that forms an inner front wall 32 of the chamber 14.

Meanwhile, the rear surface 32 of the first generally disc-shaped part 16 has a first rearwardlyextending annular ridge 34 formed upon it, which separates the peripheral flange portion 28 from the central portion 30. The annular ridge 34 has a generally planar rear surface 36, which bears against the outer peripheral edge of a circular colorimetric test disc 38 (the porous or perforated element).

The rear surface 32 of the first generally disc-shaped part 16 also has a second rearwardlyextending peripheral ridge 35, which serves, in use, to strengthen/stiffen the peripheral flange portion

28.

The first generally disc-shaped part 16 is manufactured from an optically clear transparent plastics material, such as polystyrene, such that the colorimetric test disc 38 is visible through it by looking 40 through the central portion 30. Thus, the colour of the colorimetric test disc 38 can be assessed by visual inspection.

Affixed to the front of the peripheral flange portion 28 is a colour chart decal 41, whose inner edge registers with the outer edge of the colorimetric test disc 38. Thus, in use, the colour of the colorimetric test disc 38 can be compared with corresponding coloured portions of the colour chart decal 41 by visual inspection to obtain a colorimetric reading of the fluid (not shown) within the chamber 14.

The second generally disc-shaped part 18 has a generally circular rear surface 42 from which the spigot 22 extends centrally/coaxially. The spigot 22 has a plain exterior surface to which a pushfit tube fitting (not shown) can be fitted, in use.

The second generally disc-shaped part 18 has a forwardly-extending peripheral ridge 44 whose inner surface 46 is a tight friction fit with the outer surface 48 of the first rearwardly-extending annular ridge 34. This creates a snap-together, sealing connection between the first and second generally disc-shaped interconnected parts 16, 18. The forwardly-extending peripheral ridge 44 also has a generally planar front surface portion 50, which bears against opposite side of the outer peripheral edge of the circular colorimetric test disc 38, to clamp it in position. This configuration divides the chamber 14 in two by the circular colorimetric test disc 38, such that a test fluid (not shown), must pass though the circular colorimetric test disc 38 when flowing from the inlet 20 to the outlet 22.

The second generally disc-shaped part 18 is manufactured from an opaque plastics material, such as white polystyrene, such that the colorimetric test disc 38 is shaded by the second generally disc-shaped part 18, in use. This increases the shelf-life of the colorimetric test disc 38 by reducing its light exposure.

A cap 60 is provided, which can be push-or screw-threadedly fitted to the spigot 20 of the first generally disc-shaped part 16. The cap 60 has a main body portion 62 with an internal spigot 64 that engages the interior of the first spigot 20, and a hollow interior having a surface 66 that engages the exterior of the first spigot 20. The main body portion 62 terminates in a radially outwardly extending cap flange portion 68, which overlies the central portion 30 of the circular front surface 24 of the first generally disc-shaped part 16.

The outer periphery of the of the cap flange portion 68 comprise a lip 70, which inhibits or prevents incident light at glancing angles from illuminating the colorimetric test disc 38 through any gap between the cap 60 (when fitted) and the first chamber part 18.

The radially outwardly extending cap flange portion 68 of the cap 60 shades the transparent part of the first generally disc-shaped part 16, and hence the colorimetric test disc 38 when the in-line tester 10 is not in use, thereby increasing the shelf-life of the colorimetric test disc 38 by reducing its light exposure.

As can be seen, in particular, from Figures 3 and 4 of the drawings, the colorimetric test disc

38 comprises an air-permeable membrane, which permits air to pass through it, but not fluids. In the illustrated embodiment, the colorimetric test disc 38 is manufactured of paper, which when dry, comprises pores or perforations that allow air or gasses to pass through the material, but which, when wetted, for example by an aspirated liquid, the liquid closes the pores or perforations thereby preventing fluids (air and/or gas and/or liquid) to pass through it. The colorimetric test disc 38 comprises two components, namely a liquid-absorbent layer 37, such as paper, and a porous or perforated hydrophobic layer 39. The two layers 37, 39 are conjoined to form a laminated structure.

In this embodiment, the hydrophobic layer 39 comprises pores or perforations that enable, when dry, air to pass through them (i.e. through the hydrophobic layer 39). However, when wetted by liquid,

e.g. absorbed by the liquid-absorbent layer 37, the liquid is repelled from the surface of the hydrophobic layer 39 and forced to overlie the less hydrophobic regions, that is to say, the openings of the pores or perforations. Provided the pores or perforations of the hydrophobic layer 39 are small enough (i.e. significantly smaller than the size of a water droplet), the water that overlies the pores or perforations effectively blocks the pores or perforations, thus inhibiting or preventing the passage of air or liquid through them. The aforesaid configuration conveniently converts the in-line tester 10 into a self-closing valve that permits air or gasses to pass through it when the colorimetric test disc 38 is dry, but which when the colorimetric test disc 38 is wetted, self-seals to prevent fluids from passing through the in-line tester 10.

The invention is not restricted to the details of the foregoing embodiment, which is merely exemplary of the invention. In particular, any dimensions, materials, flow directions, shapes etc.

whether stated or implied are illustrative only of a particular embodiment of the invention, and are not necessarily restrictive of the scope of this disclosure, or of the invention, whose scope is determined by the appended claims.

Claims

Claims:

1. An in-line tester comprising an inlet, an outlet and a chamber interposed between the inlet and the outlet; and a porous or perforated element comprising a colorimetric substance located within the chamber; the chamber comprising first and second interconnected parts each comprising formations that clamp a periphery of the porous or perforated element therebetween to separate the inlet from the outlet, wherein a first one of the chamber parts comprising the inlet is manufactured from a substantially transparent material, and wherein at least one of the first and second chamber parts comprises a chamber flange portion extending radially outwardly from the chamber, the said chamber flange portion comprising a colour chart arranged such that the colour chart can be compared with the porous or perforated element when viewed through the substantially transparent chamber part.

2. The in-line tester of claim 1, wherein the chamber flange portion is integrally formed with the respective chamber part.

3. The in-line tester of claim 1 or claim 2, wherein the chamber flange portion comprises a substantially flat or planar surface to which the calibration chart is affixed.

4. The in-line tester of any preceding claim, wherein the calibration chart comprises a decal affixed to the chamber flange portion.

5. The in-line tester of any preceding claim, wherein the calibration chart comprises regions of different colours, which coloured regions are located at an edge of the calibration chart, and wherein the said coloured regions are located directly adjacent, or slightly overlapping, the porous or perforated element.

6. The in-line tester of any preceding claim, wherein the colour chart is arcuate or donut shaped, and at least partially surrounds the porous or perforated element.

7. The in-line tester of any preceding claim, wherein the colour chart comprises a pH colour chart.

8. The in-line tester of any preceding claim, wherein the first and second chamber parts are clipped, glued, welded or otherwise fixed together and comprise a formation adapted to clamp a periphery of the porous or perforated element between the two parts.

9. The in-line tester of claim 8, wherein the clamping of the said periphery forms a seal between a periphery of the porous or perforated element and either or both of the two parts of the chamber, thereby separating the inlet from the outlet by the porous or perforated element.

10. The in-line tester of any preceding claim, wherein the porous or perforated element permits air or gasses to pass through it, but inhibits and/or prevents the passage of liquids through it.

11. The in-line tester of claim 10, wherein the porous or perforated element comprises an air permeable membrane, which permits air to pass through it, but not fluids.

12. The in-line tester of claim 10 or claim 11, wherein the porous or perforated element forms part of a self-closing valve that allows dry fluids to enter the chamber, but which automatically closes-off when wetted.

13. The in-line tester of any preceding claim, wherein the porous or perforated element is manufactured of a paper material comprising pores or perforations, the pores or perforations being open when dry to allow air or gasses to pass through the material, but which pores or perforations, when wetted, in use, by an aspirated liquid, close or become blocked, thereby inhibiting or preventing the aspirated liquid from passing through them.

14. The in-line tester of any preceding claim, wherein the porous or perforated element comprises a liquid-absorbent layer and a porous or perforated hydrophobic layer, the two layers being conjoined to form a laminated structure.

15. The in-line tester of claim 14, wherein the hydrophobic layer comprises pores or perforations that enable, when dry, air to pass through them, but when wetted by an aspirated liquid, the hydrophobicity of the said layer causes liquid to be repelled from the surface of the hydrophobic layer to overlie the openings of the pores or perforations.

16. The in-line tester of claim 14 or claim 15, wherein the pores or perforations of the hydrophobic layer are smaller than the size of a water droplet.

17. The in-line tester of any preceding claim, wherein the colorimetric substance is selected to test for the presence of a target substance, the target substance being any one or more of the group comprising: an acid, a base (alkali), carbohydrate, glucose, sugar, blood, iron, protein, ketone, bilirubin, urobilinogen, nitrates, leukocytes, etc.

18. The in-line tester of claim 17, wherein the porous or perforated element comprises litmus paper.

19. The in-line tester of any preceding claim, wherein the inlet or outlet comprise connectors adapted for detachable connection of items thereto.

20. The in-line tester of claim 19, wherein the connector comprise any one or more of the group comprising: a Luer lock connector; a bayonet-type fitting; a screw thread; and a push-fit connector.

21. The in-line tester of claim 20, wherein the inlet comprises a female Luer or female Luer-lock connector.

22. The in-line tester of claim 20 or claim 21, wherein the outlet comprises a male Luer or male

Luer-lock connector.

23. An in-line tester substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

Intellectual

Property

Office

Application No: GB 1611784.8 Examiner: Dr Stephen Driver