A System and Apparatus for Fluid Sample Delivery

Abstract

Systems and methods for analysing a fluid including a fluid sample delivery application. The system includes a sensing element configured to respond to at least one analyte in a sample of fluid. A detector is provided, configured to sense the response to the analyte by the sensing element. The fluid sample delivery apparatus includes a dosage needle configured to deliver the sample of fluid to the sensing element, at least one pump configured to control flow of fluid through the dosage needle, and at least one actuator configured to move the dosage needle relative to the sensing element. At least one controller is provided, configured to control the at least one pump and the at least one actuator.

Claims

1. A system for analysing a fluid, including: a sensing element configured to respond to at least one analyte in a sample of fluid; a detector configured to sense the response to the analyte by the sensing element; a fluid sample delivery apparatus, including: a dosage needle configured to deliver the sample of fluid to the sensing element; at least one pump configured to control flow of fluid through the dosage needle; and at least one actuator configured to move the dosage needle relative to the sensing element; and at least one controller configured to control the at least one pump and the at least one actuator.

2. The system of claim 1, wherein the at least one controller is configured to: position the dosage needle relative to the sensing element such that a gap is provided between at least a portion of an end of the dosage needle from which the sample of fluid is delivered and the sensing element; deliver a predetermined volume of the sample fluid to the sensing element through the dosage needle; aspirate at least a portion of the sample fluid back from the sensing element.

3. The system of claim 2, wherein the controller is configured to aspirate the sample fluid from the sensing element such that an air gap is produced between at least a portion of the end of the dosage needle and residual sample fluid on the sensing element.

4. The system of claim 2, wherein the at least one controller is configured to initiate aspiration of the sample fluid after a predetermined period of time following delivery of the predetermined volume of the sample fluid.

5. The system of claim 1, including a wicking feature configured to contact a drop of the fluid suspended from the dosage needle when the dosage needle is in a predetermined position relative to the wicking feature.

6. The system of claim 5, wherein the controller is configured to prepare the sample of fluid in the dosage needle prior to delivery to the sensing element, including positioning the dosage needle proximate to the wicking feature, such that the drop of the fluid is wicked away from the dosage needle by the wicking feature.

7. The system of claim 6, wherein the system is configured such that the end of the dosage needle at which the drop is formed is laterally spaced from the wicking feature when positioned to be proximate to the wicking feature.

8. The system of claim 1, including a chamber having an upper wall having an aperture configured to receive the dosage needle.

9. The system of claim 8, wherein the controller is configured to form a drop on the end of the dosage needle prior to insertion into the aperture of the chamber.

10. (canceled)

11. (canceled)

12. The system of claim 8, including a wicking feature configured to contact a drop of the fluid suspended from the dosage needle when the dosage needle is in a predetermined position relative to the wicking feature, wherein the inner surface of the upper wall is sloped downwardly towards the wicking feature.

13. The system of claim 8, wherein the chamber includes: a waste port positioned at a lowermost point in the chamber; a waste pump provided to the waste port; an overflow port positioned above the aperture in the upper wall; and an overflow valve provided to the overflow port to prevent backflow into the chamber through the overflow port.

14. The system of claim 13, wherein the chamber includes an air bleed valve configured to permit inflow of air to provide pressure equalisation.

15. (canceled)

16. The system of claim 1, wherein the dosage needle includes a barrel portion having a tip from which the sample of fluid is delivered, and a seal provided on the exterior of the barrel portion.

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)

21. (canceled)

22. The system of claim 1, wherein the sensing element is a bioresponsive element.

23. The system of claim 1, wherein the sensing element is configured to provide an optically detectable reaction in response to the at least one analyte.

24. (canceled)

25. The system of claim 1, wherein the sensing element includes an absorbent pad.

26. The system of claim 1, wherein the at least one pump is a peristaltic pump.

27. (canceled)

28. (canceled)

29. A method for analysing a fluid, including: moving, using at least one actuator, a dosage needle of a fluid sample delivery device relative to a sensing element; delivering a sample of fluid to the sensing element via the dosage needle by controlling at least one pump configured to control flow of fluid through the dosage needle, wherein the sensing element is configured to respond to at least one analyte in a sample of fluid; and sensing, using a detector, a response to the at least one analyte by the sensing element.

30. The method of claim 29, wherein delivering the sample of fluid includes: positioning the dosage needle relative to the sensing element such that a gap is provided between at least a portion of an end of the dosage needle from which the sample of fluid is delivered and the sensing element; delivering the sample of fluid as a predetermined volume of the fluid to the sensing element through the dosage needle; aspirating at least a portion of the delivered sample of fluid back from the sensing element.

31. The method of claim 29, including the step of preparing the sample of fluid in the dosage needle prior to delivery to the sensing element, wherein preparing the sample of fluid includes positioning the dosage needle proximate to a wicking feature, such that a drop of the fluid formed on a tip of the dosage needle is wicked away from the dosage needle by the wicking feature.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0071] Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

[0072] FIG. 1 is a schematic diagram of an exemplary livestock management system in which an aspect of the present disclosure may be implemented;

[0073] FIG. 2 is a schematic diagram of an exemplary sensor system according to one aspect of the present disclosure;

[0074] FIG. 3A is a perspective view of an exemplary chamber for use in the sensor system;

[0075] FIG. 3B is a side view of a portion of the exemplary chamber;

[0076] FIG. 3C is an end cross-section view of a portion of the exemplary chamber;

[0077] FIG. 4A-C are side cross-section views of a dosage needle illustrating different filling conditions;

[0078] FIG. 5 is a side view of an exemplary dosage needle for use in the sensor system;

[0079] FIG. 6A is a side cross-section view of an exemplary dosage needle engaged in an exemplary chamber;

[0080] FIG. 6B is a side cross-section view of the exemplary dosage needle and chamber;

[0081] FIG. 7 is a side view of an exemplary dosage needle engaged in an exemplary chamber, illustrating wicking of sample fluid from the needle;

[0082] FIG. 8 is a side view of another exemplary configuration of a dosage needle and chamber;

[0083] FIG. 9 is a flow diagram of a method of preparing a dosage needle for delivery of a sample of fluid to a sensor element;

[0084] FIG. 10 is a flow diagram of a method 1000 of pre-preparation of a dosage needle;

[0085] FIG. 11 is a flow diagram of a method 1100 of producing a drop at the tip of a dosage needle;

[0086] FIG. 12 is a flow diagram of a method 1200 of delivering a sample of fluid to a sensor element using a dosage needle;

[0087] FIG. 13A-C illustrate the tip of a dosage needle relative to a bioresponsive element during delivery of a sample of fluid;

[0088] FIG. 14A-C illustrate examples of dosage needles including at least one spacing feature; and

[0089] FIG. 15 is a flow diagram of a method of cleaning a dosage needle and sample chamber in place.

DETAILED DESCRIPTION

[0090] Exemplary embodiments are discussed herein in the context of analysis of milk. However, it should be appreciated that the various systems, apparatus and methods of the disclosure discussed herein may be applied to the analysis of other fluids.

[0091] FIG. 1 illustrates a livestock management system 100, within which a local hardware platform 102 manages the collection and transmission of data relating to operation of a milking facility. The hardware platform 102 has a processor 104, memory 106, and other components typically present in such computing devices. In the exemplary embodiment illustrated the memory 106 stores information accessible by processor 104, the information including instructions 108 that may be executed by the processor 104 and data 110 that may be retrieved, manipulated or stored by the processor 104. The memory 106 may be of any suitable means known in the art, capable of storing information in a manner accessible by the processor 104, including a computer-readable medium, or other medium that stores data that may be read with the aid of an electronic device. The processor 104 may be any suitable device known to a person skilled in the art. Although the processor 104 and memory 106 are illustrated as being within a single unit, it should be appreciated that this is not intended to be limiting, and that the functionality of each as herein described may be performed by multiple processors and memories, that may or may not be remote from each other. The instructions 108 may include any set of instructions suitable for execution by the processor 104. For example, the instructions 108 may be stored as computer code on the computer-readable medium. The instructions may be stored in any suitable computer language or format. Data 110 may be retrieved, stored or modified by processor 104 in accordance with the instructions 110. The data 110 may also be formatted in any suitable computer readable format. Again, while the data is illustrated as being contained at a single location, it should be appreciated that this is not intended to be limiting—the data may be stored in multiple memories or locations. The data 110 may also include a record 112 of control routines for aspects of the system 100.

[0092] The hardware platform 102 may communicate with various devices associated with the milking facility, for example: in-line sensors 114a to 114n associated with individual milking clusters within the milking facility, and sample sensors in the form of on-line sensors 116a to 116n associated with the individual milking clusters.

[0093] Animal identification devices 118a to 118n are provided for determining an animal identification (“animal ID”) of individual animals entering, or within, the milking facility. More particularly, the animal identification devices 118a to 118n may be used to associate an animal ID with each of the milking clusters associated with the in-line sensors 114a to 114n and on-line sensors 116a to 116n, such that the sensor data may be attributed to the individual animals. A variety of methodologies are known for the determination of an animal ID—for example a radio frequency identification (“RFID”) reader configured to read a RFID tag carried by the animal. In an alternative embodiment, or in conjunction with the animal identification devices 118a to 118n, a user may manually enter (or correct) animal IDs via a user device—examples of which are discussed below.

[0094] The hardware platform 102 may also communicate with user devices, such as touchscreen 120 located within the milking facility for monitoring operation of the system, and a local workstation 122. The hardware platform 102 may also communicate over a network 124 with one or more server devices 126 having associated memory 128 for the storage and processing of data collected by the local hardware platform 102. It should be appreciated that the server 126 and memory 128 may take any suitable form known in the art—for example a “cloud-based” distributed server architecture. The network 124 potentially comprises various configurations and protocols including the Internet, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies—whether wired or wireless, or a combination thereof. It should be appreciated that the network 124 illustrated may include distinct networks and/or connections: for example, a local network over which the user interface may be accessed within the vicinity of the milking facility, and an internet connection via which the cloud server is accessed. Information regarding operation of the system 100 may be communicated to user devices such as a smart phone 130 or a tablet computer 132 over the network 124.

[0095] Referring to FIG. 2, an exemplary sensor 200 is illustrated, which may be used as one or more of the on-line sensors 116a to 116n. In this exemplary embodiment, the on-line sensor 200 includes a biosensor 202 having a bioresponsive element 204 and a detector 206, configured to sense interaction of an analyte within a milk sample with the biosensor element. For example, the biosensor 202 may be a colorimetric sensor having a camera configured to capture the colour of a reaction-pad assay. Various colorimetric based tests are known in the field of animal health and milk quality, for example detecting lactate, beta-hydroxybutyrate (BHB), and urea.

[0096] A sample delivery tube 208 is connected near or at the bottom of a source of the fluid to be sampled—for example milk jar 210—and connects the milk jar to a fluid delivery apparatus (generally indicated by arrow 212). The fluid delivery apparatus 212 includes a dosage needle 214 mounted to needle actuator 216, configured to manipulate the position of the dosage needle 214 relative to associated components of the sensor 200. A first peristaltic pump (herein referred to as sensor pump 218) is provided to control flow of milk through the dosage needle 214 from the milk jar 210, with a first non-return valve 220 preventing flow of milk back through the sample delivery tube 208.

[0097] A sample chamber 222 is provided for preparation of the dosage needle 214 prior to delivery to the biosensor 202, and subsequent cleaning. A waste outlet is provided with a valve in the form of first duckbill valve 224, connected to waste 226 via a sample waste pump 228. An overflow port is provided with a check valve in the form of a second duckbill valve 230, connected to waste 226 downstream of the sample waste pump 228. An air inlet valve in the form of third duckbill valve 232 is provided between the chamber 222 and atmosphere.

[0098] A controller 234 is provided to control the operation of the various components described, receive data obtained by the biosensor 202, and communicate over a network such as the network 124.

[0099] FIG. 3A to 3C illustrate an exemplary embodiment of the sample chamber 222, in the form of sample chamber 300. The sample chamber 300 includes a hollow chamber 302. The hollow chamber 302 is defined by an upright wall 304, upper wall 306 (having a dosage needle aperture 308), second wall 310, rear wall 312, and a front wall (not illustrated, but spanning the hollow chamber 302 opposite the rear wall 312). A waste port 314 is provided at the nadir of the hollow chamber 302, to which the first duckbill valve 224 of FIG. 2 may be provided. In the exemplary embodiment illustrated, the sample chamber 300 includes an adjustment member 316 having an elongate slot 318 which may be used to adjust the position of the sample chamber 300 (particularly height) relative to a reference point.

[0100] Referring to FIG. 3B, the upright wall 304 of sample chamber 300 includes an upright inner surface 320 facing into the hollow chamber. In the exemplary embodiment illustrated, the angle of the upright inner surface 320 relative to ground is substantially 60°. The upper wall 306 of sample chamber 300 includes a downward facing inner surface 322 facing into the hollow chamber. In the exemplary embodiment illustrated, the angle of the downward facing inner surface 322 relative to ground is substantially 5°, sloping downwardly towards the upright wall 304.

[0101] While not illustrated, an overflow port may be provided at position 324 (herein referred to as “outlet port 324” for ease of understanding), in either the rear wall 312 or front wall (not illustrated). The overflow port 324 is provided above the dosage needle aperture 308 (not illustrated in FIG. 3B, but see FIG. 3A), such that when the hollow chamber is filled with a fluid, the tip of a dosage needle inserted through the dosage needle aperture 308 is covered by the fluid before reaching the overflow port 324. The second duckbill valve 230 of FIG. 2 may be provided at overflow port 324. An air inlet may be provided at position 326 (herein referred to as “air inlet 326” for ease of understanding), in either the rear wall 312 or front wall (not illustrated). The third duckbill valve 232 of FIG. 2 may be provided at air inlet 326.

[0102] Variation in the volume of fluid delivered through a dosage needle may be influenced by the filling of the needle prior to delivery—particularly relative to the needle tip. FIG. 4A illustrates a preferred condition, in which a dosage needle 400 having tip 402 is filled with the sample fluid 404 such that it is flush with the tip 402. However, it has been observed that with relatively small internal diameters of a needle (for example, in the order of 1.3 mm), relatively low flow rates, and surface tension of the sample fluid, the sample fluid exits the needle as a series of droplets when suspended in open air. As a result, and with reference to FIG. 4B, a drop 406 of various volumes may be produced at the tip 402 of the needle 400 once the flow of sample fluid 404 has stopped (for example, depending on where an associated pump finishes in relation to the fluid flow). Excess drops 406 may be generally undesirable because they can have a volume (for example, 50 μL) that is significant in comparison with the volume to be applied to the sensor (for example 3 to 5 μL), potentially causing large variations and a reduction in repeatability. Excess drops 406 also have a risk of being knocked off during needle movement, thereby causing soiling of components within the system. As shown in FIG. 4C, if the needle 400 is underfilled (whether by stopping pumping of the fluid 404 short of the needle tip 402, or by a falling drop drawing additional fluid with it) the volume of the sample may be undersized.

[0103] FIG. 5 illustrates an exemplary dosage needle 500. A needle barrel 502 includes a bore 504 (for example, having an internal diameter of about 1.3 mm), having a barbed end 506. A seal in the form of a silicone sleeve 508 is positioned on the needle barrel 502 such that the end of the sleeve 508 is flush with that of the barbed end 506, to present a tip surface 510. The barbed end 506 produces a taper 512 on the exterior of the sleeve 508 at the tip end.

[0104] In use, the distal end of the needle 500 from the tip 506 will be connected to a sample delivery tube. However, for illustrative purposes, in FIG. 5 a second configuration of a dosage needle tip and seal is shown. In the second configuration, a straight needle barrel 514 terminates in a bevelled tip 516. A seal in the form of a silicone bung 518 is positioned on the straight needle barrel 514, such that the bevelled tip 516 projects beyond the silicone bung 518.

[0105] In the exemplary embodiment illustrated, the dosage needle 500 includes means for adjusting the height of the dosage needle relative to other components in the system—more particular an external thread portion 520 configured to engage with a threaded bore of a needle carrier (for example, of fluid delivery apparatus 212), and a tool engaging portion 522 for rotation of the dosage needle 500 to carry out the height adjustment.

[0106] FIG. 6A illustrates an exemplary relationship between a sample chamber 600 and a dosage needle 602 having a needle barrel 604 surrounded by silicone sleeve 606. The dosage needle 602 is inserted through a dosage needle aperture in the chamber 600, such that a tip 608 of the needle 602 closest to the upright wall 610 is at least flush with the inner surface 612 of the upper wall of the chamber 600—and preferably projecting into the chamber.

[0107] Referring to FIG. 6B, the dosage needle aperture 614 is tapered towards the interior of the chamber 600. The angle of the taper of the dosage needle aperture is greater than the taper on the exterior 616 of the seal 606, such that the sealing interface occurs at the inner surface 612 rather than recessed within the aperture 614.

[0108] Referring to FIG. 7, the inner surface 700 of the upright wall of the chamber is sufficiently close to the tip 702 of the dosage needle (when inserted into the chamber) such that a drop 704 of sample fluid forming on the tip 702 contacts the inner surface 700 of the upright wall. As the drop 704 grows in volume, the force of gravity on the mass of the drop 704 is enough to break the adhesion to the tip 702. The drop 704 needs to make contact with the inner surface 700 before gravity releases it from the tip 702, so that surface tension is broken and the fluid is gently wicked away—rather than drawing additional fluid to result in the underfilled state shown in FIG. 4C.

[0109] FIG. 8 illustrates an alternative embodiment of the interior 800 of the sample chamber, having an upright wall portion 802 and a sloped ledge 804, with a curved corner 806 therebetween, and a waste port 808 at the base of the upright wall 802. The sloped ledge 804 accommodates an arrangement in which a narrow needle 810 is surrounded by a sealing bung 812 having a substantially greater diameter. In the exemplary embodiment illustrated, the needle 810 projects beyond the bung 812. It is envisaged that for embodiments in which the needle 810 is thin walled, and therefore cannot easily accommodate measures such as a bevelled or tapered tip, this extension may assist with reducing the likelihood of sample fluid tracking up the exterior of the bung 812 to a point where it will not be cleaned.

[0110] FIG. 9 illustrates a method 900 of preparing a dosage needle (for example, dosage needle 500) for delivery of a sample of fluid to a sensor element (for example, bioresponsive element 204 of biosensor 202). In a first step 902, the needle 500 is filled to its tip with the sample fluid—for example, as illustrated in FIG. 4A. In an exemplary embodiment this may be achieved by: forming a drop at the tip of the dosage needle 502, such that it contacts an upright wall (for example, the upright inner surface 320 of upright wall 304 of sample chamber 300) and is wicked away by the upright wall. In a second step 904 the dosage needle 500 is transported to a sample delivery position—for example, above the bioresponsive element 204.

[0111] FIG. 10 illustrates a method 1000 of pre-preparation of a dosage needle, more particularly prior to method 900, or in place of step 902 of method 900. In a first step 1002, sensor pump 218 is operated at a first pump rate to purge the previous sample fluid through the dosage needle 500 into the sample chamber 300, and draw the new sample fluid into the dosage needle 500. It is envisaged that this first pump rate may be relatively fast, to produce the filling condition illustrated in FIG. 4C as the result of wicking of the sample fluid once the sample pump 218 is stopped, thereby priming the dosage needle 500 for completion of filling to the tip as illustrated in FIG. 4A.

[0112] The sensor pump 218 may be stopped at a known position, for example a predetermined point in the rotation of a peristaltic pump. More particularly, in the case of a peristaltic pump the stopping position may be prior to a roller of the pump lifting off the tube of the pump, and such that the volume of sample fluid primed to be delivered to the dosage needle 500 is sufficient to complete filling of the needle 500 and subsequently deliver a sample before the roller lifts. Lifting of the roller from the tube may produce a momentary disruption in the delivery of the sample fluid. It is envisaged that the accuracy and repeatability of the sample delivery may be improved by avoiding this position at times where greater precision is required, particularly in circumstances in which the sample volume is in the order of microlitres.

[0113] In a second step 1004, filling of the dosage needle 500 with new sample fluid for delivery to the sensor element may be completed (i.e. performing step 902 of method 900). It is envisaged that this may be achieved by operating the sensor pump 218 at a second pump rate, slower than the first pump rate, for a predetermined time to achieve the filling condition as illustrated in FIG. 4A, with any excess fluid being wicked away.

[0114] In an exemplary embodiment, the sample waste pump 228 may be operated to clear the purged sample during step 1002, but may be stopped prior to the sensor pump 218 being stopped (i.e. sensor pump 218 operates for a period after the sample waste pump 228 is stopped). More particularly, the waste pump 228 may be stopped prior to operating the sensor pump 218 at the second pump rate. It is envisaged that this may avoid producing a vacuum within the chamber as the dosage needle 500 is raised away from the docked position, which could otherwise draw sample fluid from the dosage needle to produce the filling condition as illustrated in FIG. 4C, rather than the level filling condition as illustrated in FIG. 4A.

[0115] FIG. 11 illustrates a method 1100 of producing a drop at the tip of a dosage needle, more particularly for use with method 900 (for example, to perform step 902). In step 1102, the dosage needle 500 is raised away from a docked position in which the tip of the needle is proximate to the upright wall. In step 1104, a sample delivery pump (for example, sensor pump 218) is run for a predetermined period of time to produce a drop. In exemplary embodiments, prior to step 1102 the sensor pump 218 may be run to stop at a known position (for example, a particular point in the rotation of a peristaltic pump) in order to assist with improving the precision of the drop formed in step 1104. In step 1106 the dosage needle 500 is lowered into the docked position for wicking of the drop to produce the filling condition as illustrated in FIG. 4A.

[0116] FIG. 12 illustrates a method 1200 of delivering a sample of fluid to a sensor element (for example, bioresponsive element 204 of biosensor 202) using a dosage needle (for example, dosage needle 500). In exemplary embodiments, the method 1200 may be performed following performance of one or more of methods 900, 1000, and 1100. Method 1200 will be described herein with reference to FIG. 13A to 13C, which illustrate the tip of dosage needle 500 relative to a bioresponsive element in the form of reactive pad 1300.

[0117] In a first step 1202, the tip of the dosage needle 500 is positioned at a predetermined height above the reactive pad 1300, with an air gap 1302 therebetween (for example, as shown in FIG. 13A). In step 1204, a fixed volume of sample fluid is delivered from the dosage needle 500—for example, by operating the sensor pump 218 for a predetermined period of time—such that the sample 1304 mounds up between the tip of the dosage needle 500 and the reactive pad 1300, held within the edges of the pad by natural surface tension (for example, as shown in FIG. 13B).

[0118] In step 1206, a portion of the sample fluid may be removed by aspirating the sample through the dosage needle 500 (for example, by reversing the sensor pump 218), until an air gap 1306 results with a residual layer 1308 of the sample fluid left on the reactive pad 1300. In exemplary embodiments, the method may include a step of providing a wait time between step 1204 and step 1206 to allow for partial absorption of the sample. The reaction of the reactive pad 1300 with the target analyte(s) of the sample fluid may then be analysed as known in the art of biosensors.

[0119] FIG. 14A, FIG. 14B and FIG. 14C illustrate alternative examples of dosage needles 500 which may be used with the method 1200, without a complete air gap between the dosage needle 500 and the reactive pad 1300. In these embodiments, each needle 500 includes at least one spacing feature which extends beyond a first point at which the bore of the needle 500 is opened to air—i.e. the spacing features prevent occlusion of the sample of fluid from the bore by the needle 500 pressing against the sensing element. It is envisaged that such spacing features may assist with achieving a consistent spatial relationship between the needle 500 and sensor element (for example, reaction pad 1300), which in turn has an effect on providing a consistent residual volume of the sample fluid following aspiration.

[0120] It is envisaged that the spacing feature may be configured to not interfere with attaining a filling condition such as shown in FIG. 4A. For example, the spacing feature may be spaced radially from an internal rim of the needle bore.

[0121] FIG. 14A shows a first embodiment in which one or more spacer legs 1400 extend beyond the tip of the dosage needle 500. In the example illustrated the spacer leg 1400 is spaced laterally from the surface of the dosage needle 500 at which the bore exits (i.e. the surface containing the internal rim of the bore), although alternative examples are contemplated in which the spacer leg 1400 extends from that surface. It is also contemplated that the spacer leg 1400 may be provided away from the wicking feature, in use, to reduce the likelihood of interference with the wicking process in embodiments using this feature. FIG. 14B shows a second embodiment in which spacer recesses 1402 are provided in one or more sides of the dosage needle 500, with the remaining material of the needle 500 acting as a spacer. FIG. 14C shows a similar embodiment to FIG. 14B, in which the end of the needle 500 includes an inclined section 1404 such that one portion of the needle tip contacts the reaction pad 1300 while leaving an elevated point at which the bore (not illustrated) opens above the reaction pad 1300.

[0122] While not illustrated, it is also contemplated that the spacing feature may be provided on the sensing element side of the arrangement—i.e. the spacing feature acts as a stop against the dosage needle or an associated component to define the gap between the sensing element and the dosage needle.

[0123] FIG. 15 illustrates a method 1500 of cleaning a dosage needle (for example, dosage needle 500) and sample chamber (for example, sample chamber 300) in place. In first step 1502, the sample chamber 300 is filled with a cleaning fluid—for example, by extracting cleaning fluid from milk tube 204 during a cleaning cycle of the associated milking plant. Cleaning fluid reaching the overflow port 324 floods the associated tubing. It is envisaged that in environments in which the cleaning fluid is lower than an effective cleaning temperature for a particular application on reaching the chamber 300, a heating element may be provided for heating the cleaning fluid at the chamber, or prior to delivery to the chamber.

[0124] In a second step 1504, a negative pressure differential is produced within the chamber 300 to allow an inrush of air through duckbill valve 232 to produce turbulence in the cleaning fluid. For example, the sample waste pump 228 may be operated at a faster rate to the sensor pump 218.

[0125] In exemplary embodiments, steps 1502 and 1504 may be performed a plurality of times. It is envisaged that this may be performed by continuously operating the sensor pump 218, and cycling operation of the sample waste pump 228.

[0126] For completeness, it is reiterated that while aspects of the present technology are described in the context of biosensors used for sensing of milk, alternative embodiments are expressly contemplated. By way of example, the present technology may be used in the sampling and sensing of environmental pollutants in waterways or ground water, water quality indicators in municipal water supply or waste water outlets, or spoilage indicators in food and beverage processing plants.

[0127] For a firmware and/or software (also known as a computer program) implementation, the techniques of the present disclosure may be implemented as instructions (for example, procedures, functions, and so on) that perform the functions described. It should be appreciated that the present disclosure is not described with reference to any particular programming languages, and that a variety of programming languages could be used to implement the present invention. The firmware and/or software codes may be stored in a memory, or embodied in any other processor readable medium, and executed by a processor or processors. The memory may be implemented within the processor or external to the processor.

[0128] A processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, state machine, or cloud computing device known in the art. A processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0129] The processors may function in conjunction with servers and network connections as known in the art. By way of example, the biosensor system and a central processor may communicate with each other over a Controller Area Network (CAN) bus system. In the context of milking, performance sensors, animal identification devices, and milking plant sensors may also communicate with the central processor. In an exemplary embodiment, animal identifiers, data from the sensors, and any other data may be stored in a data cloud.

[0130] The steps of a method, process, or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by one or more processors, or in a combination of the two. The various steps or acts in a method or process may be performed in the order shown, or may be performed in another order. Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes.

[0131] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “include”, “comprising”, “including”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”.

[0132] The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world. The discussion of the references states what their authors assert, and the applicant reserves the right to challenge the accuracy and pertinency of the cited documents.

[0133] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0134] Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

[0135] It should be noted that various changes and modifications to the presently disclosed embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the disclosure and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present disclosure.