AU2001252352A1 - Fluid identification device and method - Google Patents

Description

FLUID IDENTIFICATION DEVICE AND METHOD

The present invention relates to a device and method for identification of a fluid, and in particular to a device and method for the indication of the presence of a particular fluid and/or of particular impurities in a fluid.

The device and method have applications in many industrial and medical sectors where different fluids may be carried by the same conduits at different times. For example, in many applications, cleaning fluid of some type is periodically passed through conduits which normally carry desired fluids such as food or drink products, oil, gas, petroleum, medical fluids for example in intravenous lines or any other fluids to effect periodic cleaning and prevent contamination or other effect on the conduit. Applications may also be envisaged where a single conduit may be used for several fluids consecutively, whether or not a cleaning step is provided between these fluids.

The invention is particularly applicable to the identification of the presence of a specific fluid or fluids in such systems where only a small number of fluids are likely to be present in practice.

In particular the present invention has applications in breweries and in flow systems between the cellars and public areas of public houses, cafes, restaurants, bars and the like serving beer, soft drinks, wine and the like on draught. In such systems, the same conduit is likely to carry, at various times, at least a drink product, water, and cleaning fluid, and may be set up to carry more than one drink product In systems where one or more liquids are passed through the conduit, it may be desirable to determine the brand, dilution, quality and the like of a given type of liquid, without having to refer to the source.

In systems where several liquids are consecutively passed through the same conduit, it is usually essential to determine at which stage the fluid in the conduit is a pure fluid and at which stages it comprises a mix of the previous and the present fluid in the conduit. This is particularly the case in flow systems for consumable drinks or medical fluids, where the presence of residual cleaner may be injurious to health.

It is also usually essential to check whether a conduit has indeed been cleaned on a regular basis. For example, in the management of pubs and bars, regular line cleaning is necessary to ensure no build up of yeast or bacteria occurs, which may damage the quality and taste of the beer or other drink to be dispensed. In the past, it has been difficult to check how often lines are cleaned and infrequent line cleaning has only been detected by the consequent decline in quality of fluids in the line.

An attempt may be made to address these issues by providing an analysing device within the fluid conduit itself, which performs a chemical analysis of the passing fluid. However the performance of an in-line chemical analysis is likely to be a complex process involving extensive equipment, and does not always accord with the commonest practice in the fields concerned which is to draw off a small sample, for example of the drink product, and to investigate the sample to give any indication of the state of the fluid in the line.

It is thus likely to be preferred in many instances that the fluid in the conduit is analysed by the drawing off of a small sample at a downstream end and the analysis thereof. Nevertheless, such an analysis, using conventional chemical assay equipment, is still likely to be time consuming and slow. As a result, it is not likely to be a practical option for many of the fields to which the present invention relates, such as for example the field of drink supply systems. Instead, it is conventional but to apply large safety margins when cleaning such conduits for example, to ensure that supplied drinks are pure. However, such an approach leads to large degrees of waste.

Thus there exists the need for a device and method which allow quick, accurate and cost efficient identification of a fluid sample representative of the state of a fluid in a conduit, thereby overcoming the above described problems. In particular, there exists the need for a device and method which allow quick, accurate an cost efficient distinguishing between several different fluids which might be present in a particular conduit system, and which allow quick and efficient detection of whether impurities and/or mixtures of such fluid are present therein.

The above problem is resolved by the present invention.

In its broadest aspect there is provided according to the present invention a device for identification of a fluid comprising a detection part adapted to detect at least a property of a fluid sample, in data communication in use with a display part indicating the presence of a particular pre-determined fluid component responsive to a property detected by the detection part.

The detection means may be in direct contact with the fluid sample being adapted to being immersible therein, or may be in indirect contact, being adapted to engage with a fluid sample container in use, but to be in communication with the fluid by, for example, electromagnetic radiation coupling to effect detection.

The present invention is based on the surprising realisation that, in particular in systems where a relatively small number of fluids are likely to be present, it is not necessary to conduct a detailed chemical analysis on a fluid sample in order to determine the presence, the presence at a given level, or otherwise of a particular component within the fluid sample. Rather, a much simpler system is provided in accordance with the present invention wherein a property characteristic of the fluid component in question is detected or otherwise identified by the detection part, and the display part indicate the presence or absence of the fluid component in question accordingly.

In particular, the detection part detects a property characteristic of a fluid to be identified, or a property at a characteristic level indicative of a fluid to be identified, and a display part produces a display responsive to detection of the said property and hence indicative of the presence of a fluid to be identified or its presence at a given pre-determined level.

Thus, the problem is solved by display of data based on one or more, but relatively few, particular pre-determined distinctive properties, rather than a full chemical analysis. The cost and difficulties associated with a full chemical analysis are obviated.

By use of the present invention, the need to carry out extensive chemical analysis of a sample is obviated. The device and method of the present invention present is simple, cost effective and accurate means to determine the presence of particular impurities and/or the degree of purity of a fluid sample. In particular, in relation to the preferred application of the invention, the present invention provides a simple device to detect the presence of residual cleaning fluid in a drink delivery line.

Reference herein to a property characteristic of a fluid or fluid component is to a property distinctive of that fluid or fluid component and/or to a property present at a particular characteristic level. In either case, it will be understood that the property need only be characteristic of the fluid or fluid component in the context of the application of the invention in relation to other fluids or fluid components likely to be present in the system, and it will be understood that it is not suggested that the property need be characteristic of the fluid on any more fundamental level.

Reference herein to a conduit is to any pipe, channel, hose or any other pathway through which a fluid may flow.

Reference herein to a fluid is to any flowable material including water, detergent, food and drink products, oil, gas, air, and also including fluids with dissolved or mixed solids or gases or mixtures thereof.

Reference herein to a presence of a fluid or fluid element includes presence at a particular predetermined level.

The display means preferably comprise indicator means to indicate the presence of one or more pre-selected fluids. Suitable indicator means include lights, sound generating devices, alpha-numeric displays, or any suitable combination thereof. Preferably, a separate indicator means is provided for each fluid component of interest in the system in question. The indicator means may comprise means to indicate digitally the presence (or presence at a pre-determined level) of the fluid component, for example by the switching on or off of a light or sound indicator, or the indicator means may comprise means to indicate the level, concentration or purity of a particular fluid component. In this latter instance, indicator means may comprise an analogue indicator device, or may comprise an analogue-digital indicator device in which a plurality of essentially digital indicators of the presence of a particular fluid are sequentially switched on dependent upon the fluid level, to provide a general indication of the concentration or purity of the fluid in question.

In a particular preferred embodiment, the indicator means comprises at least one distinct indicator for each fluid to be detected. Preferably, the indicator means further comprises means to indicate transitional states and/or mixtures. This may be by the provision of separate indicators, by simultaneous display of indicators characteristic of each fluid present, or by a periodic display (e.g. as a flashing light) to indicate such a transitional state or mixture.

For simplicity, in a particularly preferred embodiment of the device, the indicator means comprises an indicator light for each liquid to be detected by the identification device. Control means in the display part cause the relevant indicator light to be illuminated constantly when a liquid is detected in its pure state. In transitions and mixtures, the control means cause the indicator light indicative of the primary liquid present in an impure state to display flashingly.

Suitable indicator lights include light emitting diodes. Different coloured lights may be used to indicate different fluids. The detection part preferably comprises at least two spaced sensor elements configured to sense a property of the fluid across a volume of the fluid under test.

Preferably this is a physical property of the fluid, such as a response of the fluid to an electromagnetic, sonic or thermal detection signal. Preferably therefore the detection part further comprises a means to generate such an electromagnetic, sonic or thermal signal, and to transmit the same across a volume of fluid, and means remotely disposed therefrom to receive the transmitted signal.

Preferably the sensors, and/or the transmission and reception means are electrical, optical or magnetic sensors, for example sensors to detect the colour, conductivity, dielectric behaviour, opacity, magnetic permeability or other like property of the fluid.

A preferred detection means comprises paired optical probes in the form of a laser emitter or diode or similar light emitting device and a receptor plate for the emitted light disposed remotely therefrom. This is either immersed in the fluid or placed around a fluid conduit or container which is translucent and allows emission and reception therethrough associated with fraction, diffusion and frequency change indicating density, presence of dissolved solids and colour of fluid in the conduit. By means of analysing the received light, data on a property or properties giving information regarding the fluid are obtained.

Alternatively or additionally a preferred detection means comprises a plurality of electromagnetic probes adapted to be spaced apart in the fluid or placed around a fluid conduit or container in use. This simple arrangement allows measurement of the fluid properties between the probes. Any plural number of probes, for example, two, three, four, five, six or more probes may be provided. Preferably pairs of probes, more preferably a single pair of probes, is provided for simplicity of manufacture and use.

Preferably the probes are made of electrically conductive material and not in electrical contact with each other, and are associated with means for creating an electrical potential or generating a magnetic field across the probes and means for measuring an electrical magnetic, or dielectric property of the fluid between the probes, for example, impedance.

Different fluids have different impedances, and other electrical properties, and these properties are therefore suitable for identifying fluids. Thus the impedance of, for example, air is substantially different from that of beer and that of water and the impedances of different beers, water and soft drinks also differ.

As described above, different fluids also have different light manipulation characteristics and these properties are suitable for differentiating between different fluids of single types, e.g. different brands, different dilutions of the single brand and the like. This is due to the excellent sensitivity of the process. Preferably therefore the detection part comprises a combination of light and electrical property detecting means, whereby information detected by one property can be used together with different information which is better detected by the other. For example very small traces of line cleaning solution are more easily detected by impedance determination than by light transmission.

Any known means to measure an electrical property of fluid may be employed in the present invention. For example, means may be provided to measure impedance, inductance, resistance, reactance, capacitance and other similar properties.

In a preferred embodiment the means for measuring an electrical property measures impedance. The means may measure the discharge time of a capacitor through the fluid between the probes. In this embodiment the discharge time of the capacitor is determined by the impedance of the fluid across the probes.

Any known means for creating an electrical potential between the probes may be used, of which preferred means sends a voltage pulse between the probes. In this way, the capacitor of the preferred embodiment builds up a charge intermittently which is then discharged between the probes. With a pair of probes functioning according to the preferred embodiment one of the probes may be set at a reference potential and one of the probes may receive pulses from a pulse generator.

In this construction, the means for measuring the impedance may measure a period of time corresponding to the capacitance of the fluid between the probes. Thus the identification means measures the difference in the response time between the pulses supplied to and returned from a plurality of probes, preferably a pair of probes.

In an alternative embodiment, the means for measuring the electrical property measures the capacitance of the fluid between the probes. In this embodiment the means for creating an electrical potential is preferably an oscillator and the means to measure the capacitance is preferably a frequency shift detector. It is well known that electrical properties of any material vary with temperature. Thus in the present invention the fluid identification device preferably comprises a temperature sensor for temperature correction of the impedance detected. The temperature sensor may be of any conventional type and is situated in a position to be able to accurately determine temperature of the fluids.

The temperature sensor may advantageously be a semiconductor component such as a precision integrated circuit.

It is a particular advantage of a fluid identification device as hereinbefore described that the device is readily portable for the testing of fluid samples. In a preferred embodiment, the device is configured to be immersible in a fluid contained in any suitably sized and shaped container. Alternatively however, and still within the scope of the invention, the device may be provided with an integral or attachable fluid sample container, in which case the detection part may comprise detection means adapted to engage an outside wall of the said container and measure a fluid property of fluid therein. Alternatively, and still within the scope of the present invention, the device may be adapted for measuring a property or properties of the fluid in-line in a conduit. For this application, the detection part may comprise means to co-operate with an outside wall of a conduit, which may be suitably adapted for the purpose, to measure a fluid property thereacross of a fluid flowing therein. Alternatively, the device may be configured to co-operate with a suitably adapted conduit such as to releasably engage thereon and, when so engaged, to have the detection part at least partially immersed in the fluid flowing therein.

The device preferably further comprises programming means acting in co- operation with the indicator means, which programming means are adapted to be pre-programmed with data characteristic of fluid properties of one or more pre-selected fluids, such as to actuate the display part when such properties are detected by the detection part.

Such pre-programmable characteristics may be, for example, a threshold level of a property to be measured which is characteristic of the fluid in the context of the system under investigation. The programming means may comprise an interchangeable chip, data card or the like, or an integrated programming unit.

The fluid identification device preferably further comprises a power source. This power source may be in the form of an integral battery, a disconnectable battery or power-pack, or may take the form of means for connection to an external power supply.

Suitably, means are provided to activate and de-activate the device. Preferably means are provided to automatically activate and deactivate the device. These may comprise means whereby presence of fluid in the vicinity of the detection part activates the device and/or whereby lack of presence of fluid in the vicinity of the detection part de-activates the device.

In this way the device is only in operation when in use, without the need for human intervention to switch the device on and off.

In a further aspect of the present invention there is provided a method for identification of a fluid comprising placing a detection part of a fluid identification device in operative communication with a sample of fluid to be detected so as to detect at least a property of the sample; displaying on a display part of a fluid identification device which is in data communication in use with the detection part an indication of the presence of a particular pre- determined fluid component responsive to a property detected by the detection part.

The method corresponds to the device as hereinbefore defined and corresponding method steps have the same advantages as those described for the corresponding device features.

In particular, the method may involve immersing the detection means or otherwise placing them in direct contact with the fluid sample, or may involve placing the detection means into the vicinity of the fluid sample so as to be in indirect contact, for example through electromagnetic coupling therewith.

In particular, in a preferred embodiment, the method involves the initial step of pre-programming the fluid identification device and/or of inserting a suitably pre-programmed memory unit thereinto, with data characteristic of fluid properties of one or more pre-selected fluids, such as, for example a threshold level of a property to be measured which is characteristic of the fluid in the context of the system under investigation.

Detection and identification provide information enabling determination of the need to remove cleaning fluid and the like, which is then effected by initiating rinsing or cleaning by other known methods. Detection and identification also facilitate differentiation of brand type and quality.

In a further aspect of the invention there is provided the use of the device and/or the method as hereinbefore defined for identification of any fluid or fluid mixture as hereinbefore defined. In particular, there is provided the use of the device and/or the method as hereinbefore defined to distinguish between and/or to detect impurities in drink product, cleaning fluid, water, and optionally air, in or being drawn from a drink delivery system.

In a further aspect of the present invention there is provided a kit of parts comprising the device as hereinbefore defined. In particular, a kit of parts comprises a detection part and a display part as hereinbefore described assemblable together to be in data communication in use, and optionally comprises a programmable part and a power source.

The device and method of the present invention have many varied applications in monitoring of fluid in conduits. They provide a simple, cost efficient and accurate data source for the user.

The invention is now illustrated in non-limiting manner with reference to Figures 1-6 in which:

Figure 1 is an exploded isometric view of an identification device in accordance with the invention;

Figure 2a is a top plan view of the display part of the device of Figure 1, and Figure 2b is a longitudinal section through the same;

Figure 3 is an isometric view of the sampling part of the device of Figure 1;

Figure 4 is a schematic diagram of the control logic of the analysis process of the device of Figure 1;

Figure 5 is an isometric view of an alternative embodiment of identification device in accordance with the invention. Referring first to Figure 1, the outer casing of an identification device in accordance with the invention is shown comprising a sampling part (1) and an analysis part (2) together forming the detection part, and further comprising a display part (3). In this embodiment, the three parts are releasably connectable together such that there is data communication between the sampling part and the display part through the analysis part and are shown in an exploded configuration in the drawing. In other circumstances, integral units might be preferred.

As illustrated in figure 1, the sampling part comprises a plastic casing (11) for light weight and durability having apertures (12, 13) for two detection probes (see below). The analysis part comprises a plastic casing (14) defining an enclosure (15) for receiving control and analysis electronics (not shown). The display part comprises a plastic casing (16) which is provided with an integral clip (17) so that the assembled device may be readily carried in the manner of a pen.

In use, the fluid under test is drawn from the fluid supply line into any suitable container. In this particular embodiment, the invention is particularly adapted for use in relation to supply lines for beer and the like. In this instance therefore, it is likely to be most convenient if the fluid is drawn from the draught line into a glass or similar receptacle.

The display part (3) is shown in greater detail in figure 2a (in plan view) and figure 2b (in partial longitudinal section). As shown in figure 2, the casing (16) of the display part incorporates a clip (17) and is made up of a side wall surrounding an enclosure (20) with a translucent top portion (21). A projection (26) effecting engagement with a suitable receiving means in the analysis part (2) is provided with wires (27) for the transmission of data. The enclosure (20) contains the display means, comprising control electronics (18) and visual indicators (19a, 19b & 19c) in the form of light emitting diodes, each being indicative of the presence of one of the fluids under test. The translucent nature of the cover (21) means that the light from these diodes is visibly by the user.

In this embodiment, a red LED (19a) is provided indicative of the presence of cleaning fluid, a yellow LED (19b) is provided indicative of the presence of water, and a green LED (19c) is provided indicative of the presence of the drink product such as beer.

The control electronics (18) and the analysis electronics in the analysis part (2) are set up such that when a single fluid component is present and detected by the detection part, the corresponding LED is eliminated constantly. When a mixture is present, an LED indicative of the majority component flashes on and off. In use on samples drawn sequentially from a drinks line during a typical cleaning cycle, the identification device therefore functions as follows. Initially, when the line contains cleaning fluid, red LED (19a) will be illuminated when the device is immersed in the sample. As the cleaning cycle progresses, water is passed down the drinks line testing of samples as this progresses will initially produce a flashing red LED (9a) indicative of the dilution of the cleaning fluid, then a flashing yellow LED (9b), and finally a steady yellow LED (9c) indicative of the presence of pure water in the sample. As the cycle progresses, and the drink product such as beer is reintroduced to the line, the identification device will similarly progress from flashing yellow LED (9b) through flashing green LED (9c) to steady green LED (9c).

Since the device is cheap, simple and portable, it is practical to make repeated samples during a line cleaning cycle. It is thus possible to identify immediately when the composition of the fluid in the line is pure, and excessive wastage can be avoided.

The sampling part (1) of the device is shown in greater detail in Figure 3. A lightweight plastic casing has a generally pointed lower end designed for immersion in the liquid under test and with a pair of apertures (12, 13) through which a pair of probes (25, 26) project. Data communication wires (27, 28) extend upwardly through a rear projection (29) of the casing (11) which effects mechanical and data connection with the analysis part (2).

The analysis part consists of a plastic casing (14) enclosing suitable analysis electronics in the aperture (15) for determining from the signal received from the probes the presence at a given level, and the presence in a pure or impure form, of one of the fluid components under test. The casing (14) also contains a power source (not shown).

The analysis electronics within the casing (14) need not be especially complex, since in this embodiment only three fluid components are to be detected and/or distinguished, these being the drink (for example beer), water, and line cleaning fluid. Therefore, the analysis electronics needs only to be able to distinguish between signals from the probes characteristic of these three fluids, and thereby transmit a signal to the display part (3) indicating which are present.

A schematic diagram of the control logic of the analysis process is shown in figure 4. In the sampling zone 1 the probes (25, 26) are immersed in the fluid. The probe (25) is maintained at a reference potential and the probe (26) receives pulses from a pulse generator (31) so as to generate an electrical potential between the probes. In this way, the probes (25, 26) serve as a capacitor which builds up a charge intermittently which is then discharged between the probes.

The analysis zone (2) contains means (32) to analyse the potential across the probes to identify the fluid. Initially, the signal passes to a means (33) to measure the discharge time of the capacitor through the fluid between the probes (25, 26). The discharge time of the capacitor is determined by the impedance of the fluid across the probes. Thus the device may measure the difference in the response time between the pulses supplied to and returned from the probes (25, 26) to obtain output characteristic of the fluid present therebetween. The output of the measuring means (33) is passed to a central processor (34) and by comparison with reference data in a data store (35) the central processor generates an identification signal for transmission to the display part (3).

In the present embodiment, the display part comprises a further processor (18) for processing the identification signal and actuating the LEDs (19a, 19b, 19c) appropriately as above described.

Figure 5 illustrates an alternative embodiment of the invention, in which an equivalent sampling part (1) and a generally similar control and analysis part (2) are shown, but in which an alternative display part (38) is present. The display part (38) incorporates a liquid crystal display screen (39) configured to give an alphanumeric display indicative of the presence and/or concentration of the fluid under test. The identification device in Figure 5 further incorporates into the control and analysis part a programming part (36) into which a programme chip (37) is inserted which is pre-programmed with the necessary characteristic data of fluids of interest to enable the control and display means to distinguish between the fluids of interest responsive to signals from the probes. This device is therefore not merely supplied preprogrammed for a single particular system of component fluids, but rather by provision of suitable interchangeable chips may be used in more than one fluid system.

Claims (24)

1. A device for identification of a fluid comprising a detection part adapted to detect at least a property of a fluid sample, in data communication in use with a display part indicating the presence of a particular predetermined fluid component responsive to a property detected by the detection part.

2. A device in accordance with claim 1 wherein the detection part detects a property characteristic of a fluid to be identified, or a property at a characteristic level indicative of a fluid to be identified, and a display part produces a display responsive to detection of the said property and hence indicative of the presence of a fluid to be identified or its presence at a given pre-determined level.

3. A device in accordance with claim 1 or claim 2 wherein the display means comprises indicator means to indicate the presence of one or more preselected fluids.

4. A device in accordance with claim 3 wherein the indicator means include lights, sound generating devices, alpha-numeric displays, or any suitable combination thereof.

5. A device in accordance with any preceding claim wherein a separate indicator means is provided for each fluid component of interest in the system in question.

6. A device as claimed in any preceding claim wherein the indicator means comprises means to indicate digitally the presence (or presence at a predetermined level) of the fluid component, for example by the switching on or off of a light or sound indicator.

7. A device as claimed in any preceding claim wherein the indicator means comprises means to indicate the level, concentration or purity of a particular fluid component.

8. A device as claimed in claim 7 wherein indicator means comprises an analogue-digital indicator device in which a plurality of essentially digital indicators of the presence of a particular fluid are sequentially switched on dependent upon the fluid level, to provide a general indication of the concentration or purity of the fluid in question.

9. A device as claimed in any preceding claim wherein the indicator means comprises at least one distinct indicator for each fluid to be detected, and further comprises means to indicate transitional states and/or mixtures.

10. A device as claimed in claim 9 wherein the indicator means comprises an indicator light for each liquid to be detected by the identification device.

11. A device as claimed in claim 10 wherein control means in the display part cause the relevant indicator light to be illuminated constantly when a liquid is detected in its pure state, and wherein, in transitions and mixtures, the control means cause the indicator light indicative of the primary liquid present in an impure state to display flashingly.

12. A device as claimed in any preceding claim wherein the detection part comprises at least two spaced sensor elements configured to sense a property of the fluid across a volume of the fluid under test.

13. A device as claimed in claim 12 wherein the detection part is configured to sense a physical property of the fluid, such as a response of the fluid to an electromagnetic, sonic or thermal detection signal.

14. A device as claimed in claim 13 wherein the detection part further comprises a means to generate such an electromagnetic, sonic or thermal signal, and to transmit the same across a volume of fluid, and means remotely disposed therefrom to receive the transmitted signal.

15. A device as claimed in claim 14 wherein the detection means comprises paired optical probes in the form of a laser emitter or diode or similar light emitting device and a receptor plate for the emitted light disposed remotely therefrom.

16. A device as claimed in claim 14 or claim 15 wherein the detection means comprises a plurality of electromagnetic probes adapted to be spaced apart in the fluid or placed around a fluid conduit or container in use.

17. A device as claimed in any preceding claim suitably configured to be immersible in a fluid contained in any suitably sized and shaped container.

18. A device as claimed in any preceding claim further comprising programming means acting in co-operation with the indicator means, which programming means are adapted to be pre-programmed with data characteristic of fluid properties of one or more pre-selected fluids, such as to actuate the display part when such properties are detected by the detection part.

19. A device in accordance with claim 18 wherein the pre-programmable characteristics comprise a threshold level of a property to be measured which is characteristic of the fluid in the context of the system under investigation.

20. A device in accordance with any preceding claim wherein means are provided to automatically activate and deactivate the device whereby presence of fluid in the vicinity of the detection part activates the device and/or whereby lack of presence of fluid in the vicinity of the detection part deactivates the device.

21. A method for identification of a fluid comprising placing a detection part of a fluid identification device in operative communication with a sample of fluid to be detected so as to detect at least a property of the sample; displaying on a display part of a fluid identification device which is in data communication in use with the detection part an indication of the presence of a particular pre-determined fluid component responsive to a property detected by the detection part.

22. The method of claim 21 comprising the initial step of pre-programming the fluid identification device and/or of inserting a suitably pre-programmed memory unit thereinto, with data characteristic of fluid properties of one or more pre-selected fluids, such as, for example a threshold level of a property to be measured which is characteristic of the fluid in the context of the system under investigation.

23. The use of the device and/or the method in accordance with any preceding claim for identification of any fluid or fluid mixture as hereinbefore defined and in particular to distinguish between and/or to detect impurities in drink product, cleaning fluid, water, and optionally air, in or being drawn from a drink delivery system.

24. A kit of parts comprising the device in accordance with any one of claims 1 to 20 comprising a detection part and a display part assemblable together to be in data communication in use, and optionally comprising a programmable part and a power source.