GB2552144A

GB2552144A - In-line tester with shade

Info

Publication number: GB2552144A
Application number: GB1611785.5A
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: 2018-01-17
Also published as: GB201611785D0

Abstract

An in-line tester comprises inlet and outlet 20, 22, and chamber 14 interposed between them. Porous or perforated element 38 comprising a colorimetric substance is located within the chamber, which has first and second interconnected parts 16, 18 having formations 36, 50 that clamp a periphery of element 38 between them to separate the inlet from the outlet. Element 38 may inhibit or prevent the passage of liquid through it. First chamber part 16, comprising the inlet (or outlet), is manufactured from a substantially transparent material, second chamber part 18, comprising the outlet (or inlet), from a substantially opaque material. Substantially opaque cap 60, detachably affixable to the inlet (or outlet), comprises cap flange portion 68 adapted to overlie first chamber part 16. The cap flange portion and opaque second chamber part together shade element 38 from light, thereby increasing its longevity.

Description

(71) Applicant(s):

Aspirate N Go Ltd

IC1,131 Mount Pleasant, LIVERPOOL, Merseyside, L3 5TF, United Kingdom (72) Inventor(s):

George Gallagher (74) Agent and/or Address for Service:

Hutchinson IP Ltd

Hoghton Street, SOUTHPORT, Merseyside,

PR9 0PG, United Kingdom (51) INT CL:

G01N 31/22 (2006.01) G01N 33/48 (2006.01) (56) Documents Cited:

GB 2523620 A WO 2013/117916 A1

US 20120123287 A1 (58) Field of Search:

INT CLA61B, G01N Other: WPI, EPODOC (54) Title of the Invention: In-line tester with shade

Abstract Title: In-line colorimetric tester with shade (57) An in-line tester comprises inlet and outlet 20, 22, and chamber 14 interposed between them. Porous or perforated element 38 comprising a colorimetric substance is located within the chamber, which has first and second interconnected parts 16, 18 having formations 36, 50 that clamp a periphery of element 38 between them to separate the inlet from the outlet. Element 38 may inhibit or prevent the passage of liquid through it. First chamber part 16, comprising the inlet (or outlet), is manufactured from a substantially transparent material, second chamber part 18, comprising the outlet (or inlet), from a substantially opaque material. Substantially opaque cap 60, detachably affixable to the inlet (or outlet), comprises cap flange portion 68 adapted to overlie first chamber part 16. The cap flange portion and opaque second chamber part together shade element 38 from light, thereby increasing its longevity.

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Title: In-line tester with shade

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 litmus paper test strip (or disc) needs to be kept in the dark to prevent discolouration of the colorimetric chemicals that can occur upon exposure to light. On the one hand, the test chamber needs to be at least partially transparent to enable the colour of the test strip (or disc) to be ascertained by visual inspection and without having to remove it from the chamber, whereas on the other hand, the provision of a transparent test chamber allows light in, thereby potentially leading to premature degradation of the colorimetric chemicals. The known solution to this problem is to keep the in-line testers in a box or drawer until just before use (which can be inconvenient) or to store them in opaque packaging (which adds to cost and the volume of waste material).

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 to one aspect of 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 a second one of the chamber parts comprising the outlet is manufactured from a substantially opaque material, the in-line tester further comprising a substantially opaque cap detachably affixable to the inlet and comprising a cap flange portion adapted, when affixed to the inlet, to overlie the first chamber part.

According to another aspect of 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 outlet is manufactured from a substantially transparent material and a second one of the chamber parts comprising the inlet is manufactured from a substantially opaque material, the in-line tester further comprising a substantially opaque cap detachably affixable to the outlet and comprising a cap flange portion adapted, when affixed to the outlet, to overlie the first chamber part.

When the cap is fitted, this advantageously shades the colorimetric part of the in-line tester from light, thereby avoiding the need to keep the in-line tester in a dark environment until immediately before use. The colorimetric part is kept in the dark by the operation of the opaque chamber part and the end cap in conjunction with one another. However, when the end cap is removed, for example, immediately prior to use, the colorimetric part becomes visible through the transparent part of the chamber, thus enabling it to be read. The invention therefore extends the shelf-life of an in-line tester, and because the degradation of the colorimetric substance has been slowed or avoided, the reliability of the in-line tester is therefore improved.

The substantially transparent material from which the first part of the chamber is made is suitably clear, and preferably optically clear. This permits the colour of the porous or perforated element to be ascertained by visual inspection, and without removing it from the chamber.

The substantially opaque material from which the second chamber part is manufactured is suitably manufactured from a material that filters out light of wavelengths that may degrade the colorimetric nature of the porous or perforated element. In certain embodiments of the invention, the second chamber part is manufactured from opaque, white plastics.

The cap is detachably affixable to the inlet or the outlet, as the case may be, and comprises a cap flange portion adapted, when affixed to the inlet, to overlie the first chamber part. The diameter of the cap flange portion is therefore preferably greater than the diameter of the porous or perforated element so as to prevent and/or inhibit light from illuminating the porous or perforated element. A periphery of the cap flange portion may comprise a return, lip or seal adapted to come close to, or to make contact with, the first chamber part when the cap is fitted thereto. Such a configuration may inhibit or prevent incident light at glancing angles from illuminating the porous or perforated element through any gap that might otherwise exist between the cap (when fitted) and the first chamber part.

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 has a peripheral flange portion 28 that surrounds a central portion 30 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 rearwardly5 extending 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 outer surface 46 is a tight friction fit with the inner 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 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 a second one of the chamber parts comprising the outlet is manufactured from a substantially opaque material, the in-line tester further comprising a substantially opaque cap detachably affixable to the inlet and comprising a cap flange portion adapted, when affixed to the inlet, to overlie the first chamber part.

2. 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 outlet is manufactured from a substantially transparent material and a second one of the chamber parts comprising the inlet is manufactured from a substantially opaque material, the in-line tester further comprising a substantially opaque cap detachably affixable to the outlet and comprising a cap flange portion adapted, when affixed to the outlet, to overlie the first chamber part.

3. The in-line tester of claim 1 or claim 2, wherein when the cap is fitted, the porous or perforated element is substantially shaded from light.

4. The in-line tester of any preceding claim, wherein when the cap is removed, the porous or perforated element is visible through the transparent first chamber part.

5. The in-line tester of any preceding claim, wherein the substantially transparent material from which the first part of the chamber is made is clear.

6. The in-line tester of any preceding claim, wherein the substantially transparent material from which the first part of the chamber is optically clear.

7. The in-line tester of any preceding claim, wherein the second chamber part is manufactured from a material that filters-out light of wavelengths that may degrade the colorimetric nature of the porous or perforated element.

8. The in-line tester of claim 7, wherein the second chamber part is manufactured from opaque, white plastics

9. The in-line tester of any preceding claim, wherein the diameter of the cap flange portion is greater than the diameter of the porous or perforated element.

10. The in-line tester of any preceding claim, wherein a periphery of the cap flange portion comprises a return, lip or seal adapted to come close to, or to make contact with, the first chamber part when the cap is fitted thereto.

11. The in-line tester of any preceding claim, wherein the cap comprises a main body portion with an internal spigot that engages the interior of the inlet or outlet, and a hollow interior having a surface that engages the exterior of the inlet or outlet.

12. The in-line tester of any preceding claim, wherein the cap comprises an internal thread for engaging an external thread of the inlet or outlet.

13. 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.

14. The in-line tester of claim 13, 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.

15. 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.

16. The in-line tester of claim 15, wherein the porous or perforated element comprises an air permeable membrane, which permits air to pass through it, but not fluids.

17. The in-line tester of claim 15 or claim 16, 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.

18. 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.

19. 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.

20. The in-line tester of claim 19, 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.

21. The in-line tester of claim 19 or claim 20, wherein the pores or perforations of the hydrophobic layer are smaller than the size of a water droplet.

22. 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.

23. The in-line tester of claim 22, wherein the porous or perforated element comprises litmus paper.

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

25. The in-line tester of claim 24, wherein the connector comprises any one or more of the group comprising: a Luer lock connector; a bayonet-type fitting; a screw thread; and a push-fit connector.

26. The in-line tester of claim 25, wherein the inlet comprises a female Luer or female Luer-lock connector.

27. The in-line tester of claim 25 or claim 26, wherein the outlet comprises a male Luer or male

Luer-lock connector.

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

Intellectual

Property

Office

Application No: GB 1611785.5 Examiner: Dr Stephen Driver