GB2480301A

GB2480301A - Multi-parameter sensor and method of monitoring fluid characteristics

Info

Publication number: GB2480301A
Application number: GB1007976A
Authority: GB
Inventors: Matthew Paul Stevenson
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-05-12
Filing date: 2010-05-12
Publication date: 2011-11-16
Also published as: GB201007976D0

Abstract

A multi-parameter sensor for monitoring characteristics of a fluid comprises an array of sensor elements each of which indicating a charge of parameter by demonstrating a physical change such as position or colour which is readily visually detectable. Remote monitoring is facilitated using a single optical device (1), ideally a web-enabled digital camera module (webcam). Indicia such as bar code 17 or colour chart 15 provide a reference image for the camera. Software may and identify the cartridge and calculate the quantity or change in analyte detected. The array of sensor elements is provided on a cartridge (8) or slide mountable within a cartridge holder. Cartridges are replaced when necessary or when different parameters are to be monitored.

Description

MULTI-PARAMETER SENSOR AND METHOD OF MONITORING

FLUID CHARACTERISTICS

Field of the Invention

The present invention relates to a sensor for monitoring parameters of common fluids and to a system for and method of monitoring fluid characteristics. The invention particularly relates to monitoring changes in certain physical and chemical characteristics or parameters, so as to warn of excessive levels or out-of-range values and more specifically to provide an indication of potentially toxic conditions. In a further aspect, the invention relates to providing means to rectify or attenuate the effects of changes in monitored parameters or conditions.

In the description that follows, the. fluid most often referred to is water but the skilled addressee will appreciate that other fluids, including gases such as air and carbon dioxide, for example, are considered and that no limitation should be taken or inferred by the specific references herein to aquaria, which are described as exemplary of environments where one or more of a number of parameters can change with deleterious results to the often expensive fish stock.

Background to the Invention

It is well appreciated that in various environments and processes, whether relating to liquids or gases, there are certain physical and chemical parameters that can * .* *** change imperceptibly to an observer and therefore require monitoring. An example of this but not limited to this is aquarium water where a rapid change in :. parameters can lead to toxic water. The key parameters such as salinity, ammonia concentrations and pH amongst others are not easily detectable by humans, ** S...

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particularly at the levels at which fish and certain aquatic life are vulnerable.

Testing with traditional vial based test methods cannot be done continuously and is prone to human error and batch testing may be too infrequent to catch rapidly changing conditions, it therefore tends to be done reactively when problems are already occurring. Electrical probe based sensor systems require a separate technology for each parameter which is expensive, requires constant calibration and is known for its lack of user-friendliness. Electrical sensor systems are not suitable for space-sensitive applications and they cannot monitor multiple sources simultaneously. Monitoring multiple parameters is important not just to prevent ill health or death amongst fish stock but also for ensuring the healthiest environment for plants and aquatic life, thereby increasing growth rates.

It is also noted that few, if any, currently available sensors can be used to monitor parameters from different sources or of different natures simultaneously.

Additionally, there is a significant disadvantage in not being able to correlate the effects of two or more different parameters (whether from the same or different sources) changing or the resulting change in one parameter as a consequence of a change in another.

Exemplifying of the current thinking of multi-parameter monitoring is the disclosure of UK Patent Application Publication No. 2 360 095 to MARCONI APPLIED TECHNOLOGIES LTD, in which there is provided a chemical sensor array in remote communication with detection or analysis means via a network connection. The arrangement enables sensor data or other information to be transmitted to a central monitoring site and also permits information to be sent back to the sensors through various communication means including Internet connectivity or a telephone network, including a mobile telephone network.

It will be appreciated that manual or electronic interpretation of the output of the :04 chemical sensor arrays must be conducted by skilled technicians or using often i.: :* highly expensive monitoring equipment.

Whilst such systems are common in the chemical and food processing industries and also in municipal water treatment plants, the infrastructure is not readily

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available if monitoring is required on a smaller scale.

Accordingly, it is an object of the present invention to simplify multi-parameter monitoring and to provide easy-to-use remote monitoring capability within small business and hobbyist budgets.

It is an object of the invention to seek to alleviate the disadvantages of the prior art sensor arrangements and to provide a system for and method of monitoring fluid characteristics.

It is a particular object of the invention to provide accurate sensor information in a relatively inexpensive and convenient form.

It is a further object of the present invention to provide remote sensor data without the need for expensive infrastructure and communication cost.

It is a yet further object of the invention to provide a multi-source, multi-parameter sensor so as to facilitate the monitoring of different fluids at the same time.

Furthermore, it is an object of the invention to provide a means for rectifying or attenuating the effects of changes in monitored parameters or conditions,

Summary of the Invention

Accordingly, the present invention provides a multi-parameter sensor having a plurality of sensor elements, each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable. **1*

* ** Advantageously, at least one of the sensor elements changes position in response to changes in a selected parameter. I.

Conveniently, at least one of the sensor elements changes colour in response to * changes in a selected parameter.

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Alternatively or additionally, one or more sensor elements may be selected from a sensor element having a light source or luminescence which alters in intensity in response to changes in a selected parameter and a sensor which generates a line, spot or mark of increasing density or strength.

Optionally or additionally, a sensor element incorporating a digital readout is provided.

Ideally, the sensor elements are provided in an array so that visual inspection of all the sensor elements can be made from one position.

Conveniently, the sensor array is disposed on a planar substrate to as to provide a slide.

Preferably, the sensor elements are provided in a cartridge form so as to be conveniently removable from a cartridge holder.

Advantageously, the cartridge holder includes fluid inlet and outlet paths so that the fluid to be monitored is directed past the sensor array.

Conveniently, the cartridge holder includes electrical connections facilitating provision of power to the array, if required.

In the preferred embodiment of the invention, the sensor includes a remote visual inspection means, so that the condition of each sensor element can be monitored or assessed.

Ideally, the remote visual inspection means comprises an optical capture device.

* Conveniently, the optical capture device is a digital camera module, including of : :* the type normally found in mobile telephones (celiphones) and in Internet cameras (webcams). **.

*..: Advantageously, the camera module is "web enabled", that is, connectable to the * : * * 25 Internet to facilitate remote interrogation or visual inspection of the sensor array. * e -5.-

The sensor array optionally includes reference indicia selected from: colour correction spot, to provide calibration for visual inspection of the sensors; barcodes to identify the elements within a sensor array; line generators to provide orientation indicia; and level sensors or accelerometers.

The present invention further provides a method of monitoring multiple parameters within a fluid stream, the method comprising: installing a sensor array of the type having a plurality of sensor elements each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable; and visually inspecting the sensor array.

Advantageously, visual inspection may be conducted remotely.

Ideally, visual inspection is enabled using an optical capture device.

Conveniently, the optical capture device is a "web enabled" digital camera module (webcam).

Preferably, the method includes providing means for rectifying or attenuating the *S..

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* *, Ideally, control means are provided so that upon detection of anomalous or unwanted changes in pre-selected parameters, measures may be taken to *.* * counteract said anomalies or changes. a... * *.**

: * In one arrangement, physical parameters such as fluid flow rates and temperature are controlled in response to changing conditions.

In another arrangement, chemicals or dosing materials are added to the fluid being monitored in response to said changing conditions.

In a further aspect of the present invention, there is provided a system for monitoring multiple parameters within a fluid stream, the system comprising: at least one sensor array of the type having a plurality of sensor elements each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable; and means for visually inspecting the sensor array.

Advantageously, visual inspection may be conducted remotely using an optical capture device.

Preferably, the system includes means for rectif'ing or attenuating the effects of changes to monitored parameters or conditions.

Ideally, control means are provided so that upon detection of anomalous or unwanted changes in pre-selected parameters, measures may be taken to counteract said anomalies or changes.

In one arrangement, physical parameters such as fluid flow rates and temperature are controlled in response to changing conditions.

In another arrangement, chemicals or dosing materials are added to the fluid being * 20 monitored in response to said changing conditions.

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The invention thus provides a single optical device able to continuously monitor multiple sensor areas in both gases and liquids and from multiple sources. It alerts users to dangerous shifts in the parameters being measured as well as their S...

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This autonomous device monitors critical parameters and alerts users by various methods if it predicts toxic levels will be or have been reached. The device comprises software, hardware including a single integrated digital optical capture component and a demountable replaceable cartridge or slide with embedded sensor areas specific to the parameter chosen to be monitored.

The device determines change in real time using the integrated digital optical capture component which is targeted at a set of sensor areas exposed to the liquid or gas being monitored and contained in a clear faced cartridge or alternatively on a slide. The sensor area changes are either mechanical or chemical but are always an optical output selected from, for example, a visible change in position, colour light intensity and spot or line density. The changes are in quantifiable amounts arid they are interpreted by software via the digital image captured. These changes are correlated into information regarding the critical parameters being monitored. The user can then be made aware of sudden changes or a rise in critical parameters via the device alerting through built-in sound or light alarms and via a computer and Internet connection. The integrated digital optical capture component ideally has built in illumination but it is not essential in every application. Where illumination is present, care should be taken in setting up the device to avoid reflections from the target (the sensor array). The cartridge uses known colour reference points within the sensor array to ensure proper white balance and colour correction. A simple line generator or other mechanical device provides a fixed line for any mechanical outputs to be correlated against.

Through monitoring critical parameters and creating alerts, the device allows corrective actions to be taken before parameters become dangerous. It therefore attenuates the risk of potential livestock illness or death and also can be used to monitor an environment so that it can be controlled best for growth and health.

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i..: :* Ideally, a system facilitating forced changes in a process or for adding chemicals * is provided. **.

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Beyond providing a cartridge holder, the device uses only a single significant S...

piece of hardware in the form of an integrated digital optical capture component to capture all the required information from the sensor cartridge or slide. The cartridge holder directs the fluid to be tested or monitored across the array and both cartridge holder and sensor array can be modified to measure multiple parameters from numerous sources simultaneously.

An advantage of the system is that as no sensor specific hardware is used for individual sensor areas so a change in application from air to water is possible with only a cartridge change. Furthermore, software will be able to determine the cartridge type and use of the device by an identification mark, such as a barcode, on the cartridge fitted. Also, as new sensor technologies are developed and can be integrated into the sensor array, the only part the user needs to change to get full benefit of emerging technologies is to update to a new cartridge, as the hardware will remains the same. Software updates can be provided online or on request.

Most modern software programs include an automated update routine.

It will be appreciated that when applying the sensor to the monitoring of hazardous materials or those materials which cannot be contaminated by human touch, the cartridge-based version of the present invention provides significant advantages. As the sensor array is not electrical and the electronic hardware can be separated from the cartridge by a considerable air gap, the sensor is ideal for use in the food industry and for the monitoring of parameters in toxic and potentially explosive environments.

The easily demountable replaceable sensor cartridge or slide allows for minimum sensor downtime, removes sensor drift and the need for periodic calibration by the user.

* ** The device allows for the monitoring of all chosen parameters through this one system. * **

Brief Description of the Drawings *

* * ** The present invention will now be described more particularly with reference to * the accompanng drawings, which show, by way of example only, embodiments ****** * * of multi-parameter sensing arrangements and illustrations of sensor array layouts, in accordance with the invention. In the drawings: Figure 1 is a schematic illustration of an arrangement where water is drawn from a vessel through an externally disposed cartridge, within which the water for testing or monitoring is passed over a sensor array shows an external sensor device and cartridge drawing water from a vessel through the cartridge; Figure 2 is a schematic illustration of an arrangement where the sensor array (housed within a cartridge) is disposed in a body of water and the optical capture device is separated from it by a clear wall; Figure 3 is a schematic illustration of an arrangement where a gas, such as air, is pumped into the cartridge and across the sensor array; Figure 4 is a schematic illustration of a multi-parameter visual sensor cartridge; Figure 5 is a schematic illustration of an arrangement where a simple slide based visual sensor array and cartridge holder are submerged in water; Figure 6 is a schematic illustration of a simple visual sensor slide; and Figure 7 is a schematic illustration of a multi-parameter sensor array cartridge having multiple fluid flow paths therein so as to facilitate the monitoring of different parameters from different sources simultaneously.

Detailed Description of the Preferred Embodiment * *

* .... Referring to the drawings and initially to Figures 1 to 3, a sensor of the invention * may be exposed to a fluid flow in a number of different ways, of which the following are illustrated by way of example only. It will be appreciated by the *** * skilled addressee that certain conditions and precautions must be observed when * :.. 25 handling particular fluids ranging from purity from contamination to potentially * explosive materials when incorrectly handled.

*S.q.� * * In Figure 1, visual monitoring of a liquid is conducted by pumping the liquid past an array of sensors which present physical attributes related to their condition to an optical capture device 1 such as a webcani. In this arrangement, the liquid is held in a vessel 9 and a pump 10 is provided to draw the liquid (in may cases, water) from the vessel via an inlet pipe 6 connected to a cartridge holder 3 and aligned with a cartridge 8 on which the array of sensors are disposed. The liquid is drawn past the sensor elements to be returned to the vessel 9 via an outlet pipe 7.

In the above arrangement, the inlet and outlet pipes 6, 7 have been described as being connected to the cartridge holder 3, that is, the main body of the multi-parameter sensor. In an alternative arrangement, the inlet and outlet pipes are connected directly to the sensor cartridge ensuring liquid is confined only to the areas required. However, as the cartridge is replaceable, it is suggested that, rather than decouple the inlet and outlet pipes from the cartridge, the pipes are connected permanently to the cartridge holder and inlet and outlet flow paths of the cartridge form sealed connections with inlet and outlet pipes. 0-ring seals and spring clip mounting of the cartridge within the holder ought to ensure a fluid tight seal.

It will also be appreciated that to ensure accurate reading of the sensor array, the array must be aligned with the optical device, as indicated by arrow 11. Usually, there will be an air gap between the optical device and a transparent wall of the sensor cartridge. A light source 5 may be associated with the optical device, however, this must be configured so as to minimise reflection which would otherwise hamper reading or capturing an image of the sensor array.

In use, the optical capture device 1 is either enabled by remote request or via a * .... timer so as to capture an image of the sensor array and transmit the image to a * ** target via a cable 4. The image output can be stored on a local computer or :.: transmitted over the Internet for remote monitoring or analysis. The cable 4 can S. I also be configured as an antenna. It will be understood that image data can be * 30 manually or machine interpreted, however, it will also be appreciated that certain S...

parameters shifts can be used to trigger local alarms, for example, by sounding a buzzer 2 or by flashing the light source 5, which ideally comprises at least one multi-coloured LED. Although reference is made above to image capture, it will be appreciated that the optical device may comprise a webcam which when enabled will provide a live image feed of the sensor array. In one arrangement, live image feed may comprise part of an alarm state.

In Figure 2, a similar arrangement to that shown in Figure 1 is illustrated, however in this instance the pump and feed pipes are obviated. The sensor array cartridge is placed inside a vessel 9 having clear walls (as would be normal in a fish aquarium) arid circulating liquid passes over the sensor elements 8. The corresponding fixed part of the sensor is positioned in alignment with the sensor array so that the condition of the sensor elements may be monitored via the digital optical device 1, as before. There are numerous, well-appreciated ways of ensuring alignment of the sensor array and optical device and equally numerous ways of replacing the sensor cartridge 8 without immersing a hand in the liquid.

Figure 3 is a simplified schematic representation of a system for monitoring the parameters of a gas whereby the gas is pumped past the sensor elements. As before, the integrity of seals between the gas inlet and outlet paths and the sensor is an important consideration.

Referring now to Figure 4, a sensor cartridge 8 is shown in detail. The cartridge comprises a back plate 14 to support the sensor array and to define flow path channels, including inlet and outlet fluid ports 24, 25. Although the ports 24, 25 are shown extending to the rear of the back plate 14, they can be disposed parallel to the back plate. In either arrangement, they are advantageously disposed for sealing engagement with the corresponding fixed ports of a cartridge holder. The cartridge also comprises a transparent front plate 12 which together with the back plate 14 hermetically seals the sensor array when not in use. Removable or * ** piercable sealing foils may be provided over the cartridge inlet and outlet ports 24, prior to use. In use the front plate is aligned with the optical device so that the **.

sensor elements, which will be described in more detail hereinbelow, are unobstructed. ***** * *

The sensor elements illustrated by way of example in Figure 4 include at least one colour correction strip or matrix 15 for ensuring the colours detected by the optical capture device are accurate and that white balance is maintained (particularly where brightness or intensity is a selected parameter). A fluid flow indicator 16 can be used not only to confirm fluid throughput but also measure volumetric flow. A barcode 17 is used to identify the type of sensor being used and may also indicate the nature and type of sensor elements 22 present in the array. A first position indicator 19 provides a horizontal datum and its position or movement indicates whether gas or liquid is being monitored. A similar position indicator 18 is configured to indicate the levels of a major parameter such as salinity. This hydrometer 18 will change angle relative to the datum established by the first position indicator 19 as the level of salt present in a liquid increases.

A filter 20 may also be provided to prevent debris entering the sensor array and potentially obscuring the sensor elements from the optical capture device. An alternative fluid flow meter 21 is also illustrated.

Figure 5 shows an alternative arrangement of multi-parameter sensor in which an array of sensor elements are presented as a slide 23, as illustrated in Figure 6, which is mounted to a sealed slide support structure housing the optical capture device. In this arrangement, the slide is mounted to an inner wall of support structure which has a corresponding opposite transparent inner wall through which image data is collected by the optical device housed within the support structure. The sensor can be immersed in a vessel or sealed within a gas container or flow path.

Finally, with reference to Figure 7, a multi-source, multi-parameter sensor cartridge is shown. As before, the sensor cartridge comprises a back plate 14 and S..... a transparent front pate 12. The back plate 12 defines a plurality of channels, in this case three are illustrated, and corresponding inlet and outlet ports 24,25.

* Within each channel, a sensor array is disposed, each comprising visually reactive * sensor elements 22, a fluid flow meter 16 and a liquid crystal thermometer 26. *.

Although each channel acts independently, all are simultaneously monitored by *.: ** the optical capture device.

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In the arrangements illustrated, the sensor array is purely mechanical, that is, there is no requirement for electrical power. Where digital readouts are required, battery power may be sufficient to last the lifetime of the sensor array. In situations where constant temperature or flow rate monitoring is required, electrical terminals are provided at or along the leading or trailing edge of the sensor cartridge to engage a corresponding plug or power coupling.

The system for monitoring a multi-parameter sensor and reacting to eliminate or attenuate the effects of changes in parameters utilises the information provided by the sensor to govern a central processing unit which in turn controls instrumentation in any one of a wide variety of techniques known in the art. By implementing such techniques, flow control, temperature control, concentrations of certain constituent materials and additives may be manipulated and fed into the process or environment being monitored to re-establish a steady state or a required set of parameters.

In the light of this disclosure, modifications of the described embodiments, as well as other embodiments, will now become apparent to persons skilled in this art.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the appended claims. S... * S

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Claims

CLAIMS: 1. A multi-parameter sensor having a plurality of sensor elements, each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable.
2. A multi-parameter sensor as claimed in Claim 1, in which at least one of the sensor elements changes position in response to changes in a selected parameter.
3. A multi-parameter sensor as claimed in Claim 1 or Claim 2, in which at least one of the sensor elements changes colour in response to changes in a selected parameter.
4. A multi-parameter sensor as claimed in any one of Claims 1 to 3, in which one or more sensor elements may be selected from a sensor element having a light source or luminescence which alters in intensity in response to changes in a selected parameter and a sensor which generates a line, spot or mark of increasing density or strength.
5. A multi-parameter sensor as claimed in any one of the preceding claims, in which a sensor element incorporating a digital readout is provided.
6. A multi-parameter sensor as claimed in any one of the preceding claims, in which the sensor elements are provided in an array so that visual inspection of all the sensor elements can be made from one position.
7. A multi-parameter sensor as claimed in any one of the, preceding claims, in which the sensor array is disposed on a planar substrate to as to provide a slide. *
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L: :* 8. A multi-parameter sensor as claimed in any one of the preceding claims, in which the sensor elements are provided in a cartridge form so as to be conveniently removable from a cartridge holder. * S...
9. A multi-parameter sensor as claimed in Claim 8, in which the cartridge holder includes fluid inlet and outlet paths so that the fluid to be monitored is directed past the sensor array.
10. A multi-parameter sensor as claimed in Claim 8 or Claim 9, in which the cartridge holder includes electrical connections facilitating provision of power to the array, if required.
11. A multi-parameter sensor as claimed in any one of the preceding claims, in which the sensor includes a remote visual inspection means, so that the condition of each sensor element can be monitored or assessed.
12. A multi-parameter sensor as claimed in Claim 11, in which the remote visual inspection means comprises an optical capture device.
13. A multi-parameter sensor as claimed in Claim 12, in which the optical capture device is a digital camera module, including of the type normally found in mobile telephones (celiphones) and in Internet cameras (webcams).
14. A multi-parameter sensor as claimed in Claim 13, in which the camera module is "web enabled", that is, connectable to the Internet to facilitate remote interrogation or visual inspection of the sensor array.
15. A multi-parameter sensor as claimed in any one of the preceding claims, in which the sensor array optionally includes reference indicia selected from: colour correction spot, to provide calibration for visual inspection of the sensors; * * barcodes to identify the elements within a sensor array; **.*S. * Sline generators to provide orientation indicia; and * level sensors or accelerometers. S... S...

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16. A method of monitoring multiple parameters within a fluid stream, the method comprising: installing a sensor array of the type having a plurality of sensor element each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable; and visually inspecting the sensor array.
17. A method of monitoring multiple parameters within a fluid stream as claimed in Claim 16, the method including conducting visual inspection remotely.
18. A method of monitoring multiple parameters within a fluid stream as claimed in Claim 17, in which visual inspection is enabled using an optical capture device.
19. A method of monitoring multiple parameters within a fluid stream as claimed in Claim 18, in which the optical capture device is a "web enabled" digital camera module (webcam).
20. A method of monitoring multiple parameters within a fluid stream as claimed in any one of Claims 16 to 19, in which the method includes providing means for rectifying or attenuating the effects of changes to monitored parameters or conditions.
21. A method of monitoring multiple parameters within a fluid stream as claimed in Claim 20, in which control means are provided so that upon detection of anomalous or unwanted changes in pre-selected parameters, measures may be taken to counteract said anomalies or changes.S.....

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22. A method of monitoring multiple parameters within a fluid stream as claimed in Claim 20 or Claim 21, in which physical parameters such as fluid flow s rates and temperature are controlled in response to changing conditions.

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23. A method of monitoring multiple parameters within a fluid stream, as claimed in any one of Claims 20 to 22, in which chemicals or dosing materials are added to the fluid being monitored in response to said changing conditions.
24. A system for monitoring multiple parameters within a fluid stream, the system comprising: at least one sensor array of the type having a plurality of sensor elements each of which reacting to a change of parameter by demonstrating a physical change which is readily visually detectable; and means for visually inspecting the sensor array.
25. A system for monitoring multiple parameters within a fluid stream as claimed in Claim 24, in which visual inspection is conducted remotely using an optical capture device.
26. A system for monitoring multiple parameters within a fluid stream as claimed in Claim 25, in which the system includes means for rectifying or attenuating the effects of changes to monitored parameters or conditions.
27. A system for monitoring multiple parameters within a fluid stream as claimed in Claim 26, in which control means are provided so that upon detection of anomalous or unwanted changes in pre-selected parameters, measures may be taken to counteract said anomalies or changes.
28. A system for monitoring multiple parameters within a fluid stream as claimed in Claim 26 or Claim 27, in which physical parameters such as fluid flow rates and temperature are controlled in response to changing conditions.
29. A system for monitoring multiple parameters within a fluid stream as *....* claimed in any one of Claims 26 to or Claim 28, in which chemicals or dosing materials are added to the fluid being monitored in response to said changing conditions.
30. A multi-parameter sensor substantially herein described with reference to .. and as shown in the accompanying drawings.
31. A method of monitoring multiple parameters within a fluid stream substantially as herein described with reference to the accompany drawings.
32. A system for monitoring multiple parameters within a fluid stream substantially as herein described with reference to and as shown in the accompany drawings. * S ****S* *. *S. * * S p. * . S S.. * *S* * S... *p*i S.. S p