WO2003098192A1

WO2003098192A1 - Sampling device

Info

Publication number: WO2003098192A1
Application number: PCT/NZ2003/000067
Authority: WO
Inventors: David Simon Whyte; Allan Walter Wilson
Original assignee: Sensortec Limited
Priority date: 2002-05-22
Filing date: 2003-04-16
Publication date: 2003-11-27
Also published as: AU2003222527A1; NZ519133A

Abstract

The present invention relates to an improved sampling device which is adapted to be provided in-line with a fluid line, such as a milk supply line of a milking machine syste. The sampling device provide includes an inlet (2) which engages with the fluid flow line, and an outlet (3) whci also engages with the fluid flow line. The device also includes a sampling chamber (4) which is the form of a recessed well. The well (4) is positioned between the inlet (2) and the outlet (3) and is of such dimensions that some of the fluid flowing between the inlet and the outlet falls into the well. Any bubbles entrained in the fluid rise to the top of the well, and do not interfere with the analysis of the fluid as it remains in the well. The analysis may be accomplished with the use of LEDs and associated photosensitive detectors. The natural turbulence found in milking systems is used to periodically flush the fluid from the well.

Description

SAMPLING DEVICE

TECHNICAL FIELD

This invention relates to a sampling device.

Reference throughout the specification shall be made to the use of the present invention in relation to the sampling of fluids and in particular liquids. It should be appreciated however, that the present invention could in some circumstances be used to sample flowing gas or particulate matter.

For ease of reference the present invention shall be referred to as being used within a milking system, although it should be appreciated that the present invention can be used in relation to other systems and in relation to liquids other than milk.

BACKGROUND ART

It has become increasingly important to be able to sample and measure milk characteristics, preferably during the milking process. Such characteristics may include fat, blood and water content, mastitis indicators, and so forth.

Previous systems e.g. MilkoScan (FOSS Electric A/S, a Danish limited Company of Slangerupgade 69, DK-3400 Hillerod, Denmark) have separated samples permanently from a milking system and subsequently analysed those samples, either in vitro or later on in the laboratory situation. Unfortunately, these systems have problems associated with them. To pull a sample out of the milking system requires the use of valves which can be both expensive and cumbersome. This is particularly expensive if it is desired to sample milk from individual cows or even individual quarters rather than generic milk from the whole system.

Another problem is that real time data cannot be readily obtained. For example, it may be desirable to use the data obtained by sensing milk characteristics in a control application. For example, if blood is sensed, then milk from that cow may be diverted to somewhere other than the main vat.

Another problem is that trends cannot be readily measured. The composition of milk from a single cow changes during the milking process. The taking of discrete samples off-line does not allow sufficient samples to be taken to predict trends while not adversely affecting the amount of usable milk.

Thus, it would be desirable to have a suitable inline sensor.

One of the problems with providing inline sensors for milking systems is that milking systems have two phase flow. That is, between the teat cups and the milk line, there is a mixing of milk and air. And, with the pulsation system used in milking machines there is significant turbulence. Thus, it is nearly impossible to predict the ratio of milk to air within a single volume unit.

The inclusion of air into a sample of milk to be analysed means that accurate analysis is generally thought not possible.

For example, with optical sensing the inclusion of air in a milk sample can, depending on angles in the turbulence at the time, either diffract light or allow the transmission of light. This means that there can be no ready calibration or compensation to account for the existence of air in the sample.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinence of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided an inline sampling device for sampling fluid from a fluid flow system including

an inlet from the fluid flow system, and

an outlet to the fluid flow system,

the sampling device characterized in that

there is provided a sampling chamber positioned between the inlet and the outlet, the chamber configured to allow the temporary removal of the fluid to be sampled from the fluid flow system.

According to a further aspect of the present invention there is provided an in-line sampling device for sampling fluid from a fluid flow system which includes,

an inlet from the fluid flow system, and

an outlet to the fluid flow system, and

a sampling chamber which defines a well, said sampling chamber being positioned between the inlet and the outlet, the sampling chamber being configured to allow the temporary removal of the fluid to be sampled from the fluid flow system.

Reference throughout this specification shall now be made to the fluid flow system as being incorporated within a milking machine. It should be appreciated however, that the present invention can apply to other fluid flow systems. For example, the present invention could be used in factory situations in relation to such liquids as oil and juice, and medical situations in relation to blood and so forth.

Reference throughout this specification shall be made to the fluid circulated, and to be sampled being milk. Again this should not be seen as limiting as it is possible for the present invention to be applied to other fluids including gases and particulate matter.

Discussion shall now be made to use of the present invention as being inline from somewhere between the teat cups placed on the milking animal and the main milk line. Preferably the present invention may provide an inlet sampling device positioned in a series with a milk supply line of a milking machine system. The components employed in the present invention may in some instances be located within a milk supply line or more preferably, in series as a connecting component between two adjacent sections of supply line.

Preferably the inlet and/or the outlet are of a similar diameter to the tubing/conduits or milk supply lines used in the milking system. This ensures that there is less impedance of flow through the system and that the present invention can be readily fitted into existing systems with minimal adjustments required.

Reference throughout this specification will also be made to the inlet and outlet provided having approximately the same diameter. However, in one alternative embodiment, the outlet may have a smaller diameter than the inlet, thereby potentially impeding the flow of fluid from within the sampling chamber. This restriction of the comparative size of the outlet will thereby promote the retention of fluid within the same sampling chamber for a longer period of time and therefore allowing preferably one or more measurements to be taken easily with respect to the fluid under investigation.

However, those skilled in the art should appreciate that may also be employed in conjunction with the present invention and reference to the above only throughout this specification should in no way be seen as limiting.

In preferred embodiments the inlets and outlets are made of or formed from substantially rigid tubing. Preferably such tubing may be readily fitted in line.

The sampling chamber shall now be referred to as defining a well. It should be appreciated however, that the sampling chamber can take a number of forms and one embodiment for example, may be capillary tubing which bypasses part of the milk flow. Those skilled in the art should appreciate that the sampling chamber may define a housing container or structure within which a well can be located where this well is used to contain or sample the fluid in question. Those skilled in the art should appreciate that various types and configurations of wells in addition to various types and configurations of sampling chambers or housings may be employed in conjunction with the present invention.

Preferably fluid which enters the well is analysed by at least one sensor. A sensor or in some further preferred embodiment in a plurality of sensors can be trained on the fluid temporarily trapped within the well to analyse same.

In preferred embodiments, the well is configured so that a sensor or sensors required to analyse the milk sample within the chamber operate on a known thickness of milk. In these instances, the well is adapted to capture a known thickness or width of fluid to be analysed with the sensor or sensors employed operating across this known thickness or width of fluid. This is particularly important where optical sensors are used to measure the absorption, transmission or reflectance of light being passed through the sample. This is also important for non-optical sensors such as capacitance sensors and so forth.

Reference throughout the specification shall be made to the present invention as using a plurality of optical sensors. However, it should be appreciated that other sensors can also be used.

To achieve a known path length of milk, it is important that the sample is contained within a well having rigid and preferably parallel aligned sides fixed a set distance apart.

In preferred embodiments, sensors (say transmitters and receivers) are placed on either side of the well which is optically transparent to those sensors. In preferred embodiments the sides of the well are aligned substantially parallel to each other which means that the positioning of the sensors relative to the well is not as critical as if the sides have been tapered.

Tapered or stepped sides of the well are however possible and may be particularly useful where a number of sensors are required to be used for the present invention.

For example, a shorter path length is desirable for optical sensors and therefore these can be positioned at the narrow end of the taper. However for capacitance, a greater path length may be desired and therefore these can be positioned further apart at the wider end of the taper.

A particular advantage of using a sampling device with a well is that it can be configured to assist in the separation of air from the fluid sampled. For example, the well can be positioned so that gravity (and in some cases capillary) action acts to separate the milk from the air by virtue of the milk settling into the well while the air continues to flow above the well in the main fluid flow system.

Preferably the well is sufficiently deep and has a sufficiently sized entrance to it that any air entrained in the milk does not penetrate sufficiently into the well to interfere with the path between the sensors.

For the present invention to be fully useful as a sampling device, it needs to be auto sampling with a regular exchange of fluid in the well substantially commensurate with the fluid flowing in the main system.

In a preferred embodiment of the present invention the well is configured so that the turbulence present in the milking system and its associated lines acts to periodically flush out and replace the sample within the well.

It is also important that the construction of the well is such that it can be readily cleaned, preferably through the automated cleaning processes applied to and employed by the milking system.

In a further preferred embodiment, the well includes or defines separate entry and exit regions for the fluid to be sampled. Preferably these entry and exit regions may be located on opposite sides or faces of the well to allow the well to be flushed of fluid periodically by the turbulence present in the milking system employed. The configuration of the well which readily allows fluid to pass through same provides the resulting sampling device with a configuration which allows for the temporary removal of fluid from a fluid flow system or preferably a milking system. The provision of separate entry and exit regions within the well provided allow the well to be easily cleared or flushed substantially completely.

It should be noted that the milking industry is heavily regulated, particularly with regard to dimensions of components that require cleaning in the system. Therefore, any well design needs to take into account these as well.

Having regard to the foregoing, the inventor has determined that a well having the following dimensions is particularly suitable.

In preferred embodiments the width across the well which is the effective path length of milk between the sensors is in the order of or approximately 3mm. In such embodiments the well may form a slot like channel which is wide enough to meet specifications for cleaning, but small enough to allow acceptable signal to noise rations for sensors. This leads to the minimum path length achievable through the well to be in the order of 3mm. While the path lengths can be longer, for example up to width of the inlet and the outlet, this is not desirable as detectors having a greater sensitivity or transmitters with a greater output would be required. In general the greater the path length, the less the signal to noise ratio and the greater the sensitivity needed.

Preferably the depth of the well is between 10 and 15mm, with a depth of 12mm working particularly well. A depth shallower than 10mm is likely to have air entrained in the liquid through the action of turbulence. A depth of greater than 15mm may make the well difficult to clean.

The minimum length of the well is defined by the regulated radii allowed. The maximum length is determined by the ease of cleaning it presents.

In some embodiments the device may be configured to ensure that a pulsed flow of milk would flow past the well and then some milk would dribble / fall back into the well and be analysed.

In a preferred embodiment the material employed to form the well may be transparent to an electromagnetic energy with wavelengths of between 400-1 lOOnm.

In a preferred embodiment the material employed to form the well may be plastic polysulphone.

Preferably the well is made from an optically transparent material which is certified as being suitable for milk contact. Plastic polysulphone is particularly suitable in this regard as it is optically transparent in the wavelength range of interest being 400 to 1 100 nanometres. Polysulphone is also optically stable. Other suitable materials could be any amorphous thermoplastics or thermoset.

The present invention may incorporate other features to aid manufacture. For example, there may be provided at least one guide on either side of or adjacent to the well which can allow for ready alignment and placement of the sensors.

There may also be provided at least one rib to provide attachment point or points to assist in installation assembly of a sensor.

Most of the discussion has been made to the use of the present invention in a two phase environment such as between the teat cups and the milk line. It should be appreciated that the present invention can be used in a single phase system such as that within the milk line itself. In this use of the present invention it is not necessary for the sensor to be placed so gravity can assist in separation of liquid and air. Instead, the sensor need only be placed where the turbulence of the liquid within the line ensures that fluid flows into the well. It is envisaged that in this situation the present invention can be particularly useful in detecting whether milk, detergent, wash or rinse water is in the milking system. However, in one alternative embodiment the sampling chamber may be located or positioned in the upper regions or surface of a milk line if required. In such an embodiment, gravity based settling or separation of air from milk need not necessarily be employed if readings can quickly be obtained from the sensor or sensors used in conjunction with the present invention. By providing the sampling chamber and associated well in effectively an 'upside down' position, this allows the well to be emptied quickly and easily.

It can be seen that the present invention has a number of advantages over the prior art. There is provided a means by which a sample can be taken from the line which ensures that there is little or no impedance to the flow of fluid through the system being sampled.

The present invention is particularly useful in relation to two phase systems as it allows the separation of the liquid to be sampled from the gas/air in the system.

The present invention is particularly useful in the use of sensors where a well defined path length is required to be known.

The design of the present invention is also such that auto sampling can occur in addition to auto cleaning. The auto sampling aspect allows real time data to be gathered while not sacrificing any of the fluid being sampled.

Finally, the present invention is an inherently simple and inexpensive device to manufacture, particularly in comparison with sub-sampling devices that use valves and the like to separately draw off a sample from the fluid flow system for later analysis.

BRIEF DESCRIPTION OF DRAWINGS

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:

Figure 1 is a side cross-sectional view of one embodiment of the present invention;

Figure 2 is an end cross-sectional view of one embodiment of the present invention, and

Figure 3 is a plan view of one embodiment of the present invention; and

Figures 4a & 4b show top and bottom cross section perspective views of elements of the present invention as configured in accordance with a further embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

With respect to the figures, there is illustrated a sampling device generally indicated by arrow 1.

The sampling device has an inlet (2) and an outlet (3) having the same diameter as each other and the conduits of the system to which it is to be placed.

Between the inlet (2) and outlet (3) is a well (4). In the embodiment shown the inlet (2) and the outlet (3) of approximately the same diameter and therefore may be used interchangeably with respect to one another due to the symmetry of the sampling device provided.

The well (4) is of a sufficient depth and configuration that two phase fluids (containing liquid and gas) passing through the device (1) separate out with liquid settling in the well (4) and gas passing out through the outlet (3).

The sampling device (1) is made of optically transparent polysulphone. This enables light to be passed through the well and the liquid within it. For example, light from two different LEDs (5 and 6) can pass through the well and the liquid and be detected by detector (7).

It can be seen that the configuration of the well (4) is such that the path length between the LEDs (5,6) and the detector (7) is well defined and removed from the air flow in the main part of the system. Yet, the depth of the well (4) is such that it is still possible for turbulence to exchange the sample within the well with fresh fluid causing in effect a type of auto-sampling. This same action is useful in the cleaning of the sensor with conventional inline cleaning systems.

Figures 4a & 4b show a cross section view of the lower portions of an in-line sampling device. Half the cross section of the inlet (2) and outlet (3) is shown as is the well (4) defined within the sampling chamber provided. Figure 4b illustrates the provision of a series of guides (8) adapted to assist in the location and positioning of a series of transmitting LEDs (not shown) forming a portion of the sensors to be employed by the device. Figure 4b also shows the provision of a pair of ribs (9) which define attachment points or positions for a series of photosensitive detectors (not shown).

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims

WHAT WE CLAIM IS:

1. An inline sampling device for sampling fluid from a fluid flow system which includes:

an inlet from a fluid flow system, and

an outlet to the fluid flow system, and

a sampling chamber positioned between the inline and the outlet, the chamber being configured to allow the temporary removal of fluid to be sampled from circulation within the fluid flow system.

2. An inline sampling device as claimed in 1, wherein the sampling chamber defines a well.

3. An inline sampling device as claimed in claim 2, wherein fluid within the well is analysed by at least one sensor.

4. An inline sampling device as claimed in claim any one of claims 2 or 3, wherein the well captures a known thickness or width of fluid to be analysed.

5. An inline sampling device as claimed in claim 4, wherein the width of the well is approximately 3mm.

6. An inline sampling device as claimed in any one of claims 2 to 5, wherein the well is between 10- 15mm deep.

7. An inline sampling device as claimed in claim 6, wherein the well is approximately 12mm deep.

8. An inline sampling device as claimed in any one of claims 2 to 7, wherein the well is adapted to separate air from fluid within the well.

9. An inline sampling device as claimed in claim 8, wherein gravity is used to separate air from fluid.

10. An inline sampling device as claimed in any one of claims 2 to 9, wherein at least two sides of the well are aligned substantially parallel to one another.

1 1. An inline sampling device as claimed in any one of claims 2 to 9, wherein the well includes tapering or stepped sides.

12. An inline sampling device as claimed in any one of claims 2 to 11, wherein at least one guide is provided in the chamber adjacent to the well.

13. An inline sampling device as claimed in any one of claims 2 to 12, wherein a chamber includes at least one rib to provide an attachment point for a sensor.

14. An inline sampling device as claimed in any previous claim, which includes a plurality of optical sensors.

15. An inline sampling device as claimed in any one of claims 2 to 14, wherein the material of the well is transparent to electromagnetic energy with wavelengths between 400-1 lOOnm.

16. An inline sampling device as claimed in any one of claims 2 to 15, wherein the well is formed from plastic polysulphone.

17. An inline sampling device as claimed in any previous claim, wherein the inline and outlet are formed from substantially rigid tubing.

18. An inline sampling device as claimed in any previous claim, wherein the fluid circulated within the fluid flow system is milk.

19. An inline sampling device as claimed in claim 18, wherein the fluid flow system is incorporated within a milking machine system.

20. An inline sampling device as claimed in claim 19, wherein the inline sampling device is positioned in series with a milk supply line of a milking machine system.

21. An inline sampling device as claimed in any one of claims 19 or 20, wherein the well is configured so that turbulence present in the milking machine system periodically flushes milk from inside the well.

22. An inline sampling device as claimed in any one of claims 19 to 21, wherein a well is cleaned through an automatic cleaning process employed by the milking machinery system.

23. An inline sampling device as claimed in any one of claims 19 to 22, wherein an inline and/or outlet has substantially the same diameter as milk supply lines used in the milking machine system.

24. An inline sampling device substantially as herein described with reference to and as illustrated by the accompanying drawings and/or examples.

25. A method of manufacturing and/or using an inline sampling device substantially as herein described with reference to and as illustrated by the accompanying drawings and/or examples.