TECHNICAL FIELD

The present invention relates to a milk analysis apparatus for analysing milk. The invention further relates to a method of operating a milk analysis apparatus.

BACKGROUND

Milk is analysed at different stages of its production. The milk may be analysed for various reasons, such as:

- to establish the health of a relevant milking animal or its nutritional balance status,

- for breading purposes, to document milk data for a relevant milking animal, or

- to test whether the milk is suitable for human consumption.

Various constituents of milk may be analysed such as fat content, protein content, or somatic cell count. A milk analysis apparatus may be a freestanding unit to which a relevant milk sample is manually transferred. Alternatively, a milk analysis apparatus may be an on-line unit which is connected to a milk conducting system, such as conduits in a milking machine. In the latter apparatus, milk may be automatically transferred from the milk conducting system to the milk analysis apparatus.

A milk analysis apparatus may comprise various parts for transferring a sample of milk to an analysis unit. In the analysis unit the actual analysis of the milk takes place. Some kinds of analysis units are sensitive to air pockets forming in a milk sample in the analysis unit. An analysis passage of an analysis unit is often thin, which may make it difficult to remove air pockets formed therein.

WO 2008/060235 discloses a device for counting of somatic cells and/or fat droplets in a milk sample. The device comprises a measuring chamber arranged to receive milk samples from animals, a camera adapted to record images of milk samples in the measuring chamber, and image analysing means adapted to count somatic cells and/or fat droplets in the images. The document is concerned with the cleaning of the measuring chamber.

SUMMARY

It is an object of the present invention to provide a milk analysis apparatus, in which the forming of air pockets is prevented or at least the risk of air pockets forming is alleviated. According to an aspect of the invention, the object is achieved by a milk analysis apparatus comprising an analysis unit for analysing milk, a milk collecting container, a syringe pump for pumping liquid from the milk collecting container to the analysis unit, an inlet conduit extending from the milk collecting container to the syringe pump, an outlet conduit extending from the syringe pump towards the analysis unit, an inlet valve arranged in the inlet conduit, and an outlet valve arranged in the outlet conduit. The milk analysis apparatus further comprises a passage conduit connected to the outlet valve, which passage conduit at a partition is divided into a bypass passage and an analysis passage for conducting liquid through the analysis unit. A bypass valve is arranged in the bypass passage downstream of the partition and a one-way valve is connected to the analysis passage downstream of the analysis unit.

Since the milk analysis apparatus comprises the outlet valve, the bypass valve, and the oneway valve, the milk analysis unit may be closed off by closing said three valves during drawing of a milk sample from the milk collecting container with the syringe pump. Thus, no air is admitted into the analysis passage by gravity and buoyancy, or by a negative pressure provided by the syringe pump. As a result, the above mentioned object is achieved.

Whereas it might be assumed sufficient to provide the outlet valve only, or to provide the bypass valve together with the one-way valve, to prevent air from being drawn into the syringe pump backwards via the analysis passage or the bypass passage, it has been realized by the inventor that this is not sufficient to prevent air from entering the milk analysis unit and the forming of air pockets in the milk analysis passage. It has also been realized by the inventor that this problem is best solved by providing the outlet valve, the bypass valve, and the one-way valve to close off the analysis passage of the milk analysis unit.

Connections to the passage conduit, with the bypass passage and the analysis passage, form the only fluid connections to and from the milk analysis unit. However, as realized by the inventor, at internal connections between parts in the milk analysis unit miniscule leaks may form when the analysis unit is subjected to a negative pressure, such as from the syringe pump when it performs a stroke to draw liquid into the syringe pump if the outlet valve is open or no outlet valve is present in the milk analysis apparatus.

The milk analysis unit may e.g. be adapted to analyse fat content, and/or protein content, and/or somatic cell count of milk. The milk analysis apparatus may be a freestanding unit to which a relevant milk sample is manually transferred. Alternatively, the milk analysis apparatus may be an on-line unit which is connected to a milk conducting system, e.g. a milk conducting system of an automatic milking machine comprising an implement for

automatically attaching teat cups to the teats of animals.

According to embodiments, the syringe pump may comprise an opening end, to which the inlet and outlet conduits are connected. The opening end of the syringe pump may face substantially upwardly during use of the milk analysis apparatus. In this manner, during a liquid drawing stroke, any air in the syringe pump will be collected at the opening end. The collected air will thus be readily available to be discharged from the syringe pump. According to embodiments, the milk analysis apparatus may comprise a control arrangement for controlling the syringe pump, the inlet valve, the outlet valve, and the bypass valve. The control arrangement may be adapted to maintain the outlet valve closed during drawing of liquid into the syringe pump from the milk collecting container via the inlet conduit. In this manner a negative pressure in the passage conduit, the bypass passage, and the analysis passage during a liquid drawing stroke of the syringe pump may be avoided. Air will thus be prevented from being drawn into the milk analysis unit.

According to embodiments, the control arrangement may be adapted to maintain the bypass valve closed during drawing of liquid into the syringe pump from the milk collecting container via the inlet conduit. In this manner air is prevented from entering the bypass passage from an outlet end of the bypass passage and thus, air may be prevented from reaching the analysis passage from the bypass passage.

When both the outlet valve and the bypass valve are maintained closed during drawing of liquid into the syringe pump, the advantages as discussed above will be manifested.

According to embodiments, the control arrangement may be adapted to close the inlet valve prior to completing a liquid drawing stroke of the syringe pump to create a negative pressure in the syringe pump for degassing a liquid in the syringe pump. In this manner an easily accomplished degassing of a liquid in the syringe pump may be achieved prior to discharging the liquid into the analysis unit. In particular water may be deaerated, i.e. freed from air, at least to some degree. The air might otherwise separate from the water and form air pockets in the analysis passage. According to embodiments, the control arrangement may be adapted to begin a discharge stroke of the syringe pump with the inlet valve open prior to opening the outlet valve in order to discharge any gas present in the syringe pump past the inlet valve. In this manner any gas present in the syringe pump may be discharged through the inlet conduit towards the milk collecting container. In particular air may be discharged through the inlet conduit.

According to embodiments, the control arrangement may be adapted to close the inlet valve and to open the outlet valve and the bypass valve during the discharge stroke of the syringe pump. In this manner liquid in the syringe pump is transferred towards the milk analysis unit.

According to embodiments, the control arrangement may be adapted to close the bypass valve during the discharge stroke of the syringe pump to force liquid through the analysis passage and the one-way valve.

According to a further aspect of the invention there is provided a method of operating a milk analysis apparatus comprising an analysis unit for analysing milk, a milk collecting container, a syringe pump for pumping liquid from the milk collecting container to the analysis unit, an inlet conduit extending from the milk collecting container to the syringe pump, an outlet conduit extending from the syringe pump to the analysis unit, an inlet valve arranged in the inlet conduit, and an outlet valve arranged in the outlet conduit. The milk analysis apparatus comprises a passage conduit connected to the outlet valve, which passage conduit at a partition is divided into a bypass passage and an analysis passage for conducting liquid through the analysis unit. A bypass valve is arranged in the bypass passage downstream of the partition, and a one-way valve is connected to the analysis passage downstream of the analysis unit. The method comprises:

- opening the inlet valve,

- drawing liquid into the syringe pump from the milk collecting container via the inlet conduit, while

- maintaining the outlet valve closed.

Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

Fig. 1 illustrates a milk analysis apparatus according to embodiments, and

Fig. 2 illustrates a method of operating a milk analysis apparatus according to embodiments. DETAILED DESCRIPTION

Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 illustrates a milk analysis apparatus 2 according to embodiments. The milk analysis apparatus 2 comprises an analysis unit 4 for analysing milk. The milk analysis unit 4 may e.g. comprise a Fourier transform infrared spectroscopy, FTIR, interferometer. Briefly, to elucidate the reader, a FTIR interferometer sends a beam of light containing many light frequencies into a sample of milk and measures how much of that beam is absorbed by the sample. Next, the beam is modified to contain a different combination of light frequencies, giving a further set of light absorption data. This process is repeated a number of times. A calculating unit calculates from the measured light absorption data what the absorption is at each wavelength. The analysis unit 4 comprises an analysis passage 6, into which a sample of milk is transferred for analysis of the sample. The beam of light from the FTIR interferometer passes through the analysis passage 6 and the sample of milk therein. In the direction of the light beam, the analysis passage 6 may be as narrow as 50 μΐη. If air is allowed to enter the analysis passage 6, in such a narrow passage air pockets may form. Air pockets in the analysis passage 6 may be detrimental to the quality of the analysis performed in the milk analysis unit 4, or to the calibration of the analysis unit 4.

The analysis unit 4 may comprise a different type of milk sample analysis device than an FTIR interferometer. However, also the analysis passages of other types of milk sample analysis devices may be narrow and thus, air pockets may be formed therein. Mentioned purely as an example, the analysis passage may be up to 100 μιη, up to 500 μιτι, or up to 1 mm wide.

The milk analysis apparatus 2 further comprises a milk collecting container 8, a syringe pump 10 for pumping liquid from the milk collecting container 8 to the analysis unit 4, an inlet conduit 12, an outlet conduit 14, an inlet valve 16 arranged in the inlet conduit 12, and an outlet valve 18 arranged in the outlet conduit 14. The inlet conduit 12 extends from the milk collecting container 8 to the syringe pump 10 and the outlet conduit 14 extends from the syringe pump 10 towards the analysis unit 4. The syringe pump 10 comprises a piston 20 which is moved back and forth in a cylinder 22 by a non-shown actuator. The syringe pump 10 draws liquid in a liquid drawing stroke of the piston 20 and discharges liquid in a liquid discharging stroke of the piston 20. The syringe pump 10 comprises an opening end 23, to which the inlet and outlet conduits 12, 14 are connected. The opening end 23 of the syringe pump 10 faces substantially upwardly during use of the milk analysis apparatus 2. In these embodiments, the inlet and outlet conduits 12, 14 are connected to the opening end 23 via one common conduit. Alternatively, the inlet and outlet conduits 12, 14 may be connected separately to the opening end 23.

The milk analysis apparatus 2 further comprises a passage conduit 24 connected to the outlet valve 18. The passage conduit 24 is divided into a bypass passage 26 and the analysis passage 6 at a partition 30. Liquid is conducted through the analysis unit 4 via the analysis passage 6. A bypass valve 32 is arranged in the bypass passage 26 downstream of the partition 30. A one-way valve 34 is connected to the analysis passage 6 downstream of the analysis unit 4. The milk analysis apparatus 2 in these embodiments is an on-line unit which is connected to a milk conducting system of a milking machine via connection conduits 36 and a three-way valve 38. During milking, milk may flow continuously through the connection conduits 36 and the three-way valve 38 is set accordingly. When a milk sample is to be analysed in the milk analysis apparatus 2, the three-way valve 38 is set to conduct milk into the milk collecting container 8. Similarly, during cleaning of the milk analysis apparatus 2, cleaning liquid is conducted via the three-way valve 38 to the milk collecting container 8. From the milk collecting container 8 milk, or cleaning liquid, is pumped through the milk analysis unit 4 by the syringe pump 10. The milk analysis apparatus 2 comprises a control arrangement 40 for controlling the syringe pump 10, the inlet valve 16, the outlet valve 8, and the bypass valve 32. The control arrangement 40 is adapted to maintain the outlet valve 18 closed during drawing of liquid into the syringe pump 10 from the milk collecting container 8 via the inlet conduit 12.

Furthermore, the control arrangement 40 is adapted to maintain the bypass valve 32 closed during drawing of liquid into the syringe pump 10 from the milk collecting container 8 via the inlet conduit 2. Suitably, both the outlet valve 18 and the bypass valve 32 are maintained closed during drawing of liquid into the syringe pump 10.

When a cleaning liquid containing water, such as water and a cleaning agent or clean water, is drawn into the syringe pump 10, the control arrangement 40 may close the inlet valve 16 prior to completing a liquid drawing stroke of the syringe pump 10 to create a negative pressure in the syringe pump 10 for deaerating the cleaning liquid in the syringe pump 10. Further, the control arrangement 40 may begin a discharge stroke of the syringe pump 10 with the inlet valve 16 open prior to opening the outlet valve 18 in order to discharge any air present in the syringe pump 10 through the inlet conduit 12 past the inlet valve 16, and suitably to the milk container 8 wherefrom the air may escape. Since the opening end 23 of the syringe pump 10 faces upwardly, the air will be collected at the opening end 23 readily available to be discharged. Once the air has been discharged the control arrangement 40 may close the inlet valve 16 and open the outlet valve 18 and the bypass valve 32 during the discharge stroke of the syringe pump 10. Thus, the liquid is transferred to the milk analysis unit 4. While the bypass valve 32 is open, the liquid flows primarily through the bypass passage 26. Eventually the control arrangement 40 closes the bypass valve 32 during the discharge stroke. The liquid is thus forced through the analysis passage 6 and the one-way valve 34.

Similarly, when milk is to be analysed and milk has been drawn into the syringe pump 10 from the milk collecting container 8, the control arrangement 40 closes the inlet valve 16 and opens the outlet valve 18 and the bypass valve 32 during the discharge stroke of the syringe pump 10. Thus, the milk is transferred to the milk analysis unit 4. While the bypass valve 32 is open, the milk flows primarily through the bypass passage 26. Eventually the control arrangement 40 closes the bypass valve 32 during the discharge stroke. The milk is thus forced through the analysis passage 6 and the one-way valve 34. The milk may be analysed while it flows through the analysis passage 6. Alternatively, the analysis passage 6 may be filled with milk and the milk in the analysis passage 6 may be analysed while the milk is stationary therein. Prior to pumping liquid with the syringe pump 10, the milk collecting container 8 is filled with liquid, milk or cleaning liquid, as discussed above. When milk is to be analysed, such analysis may take place during or after a first milk discharge stroke of the syringe pump 0. Alternatively, analysis of milk may take place during or after a preceding milk discharge stroke of the syringe pump 10. After milk has been analysed the conduits and passages of the milk analysis apparatus 2 may be cleaned. Water containing a cleaning agent may be used for one or more strokes of the syringe pump 10 followed by a rinsing with clean water during one or more strokes. Any remaining liquid in the milk collecting container 8 may be disposed of via a drain 42. Fig. 2 illustrates a method of operating a milk analysis apparatus according to embodiments. The milk analysis apparatus 2 may be an apparatus as discussed above in connection with Fig. 1. The method comprises:

- opening 100 the inlet valve 16,

- drawing liquid 102 into the syringe pump 10 from the milk collecting container 8 via the inlet conduit 12, while

- maintaining 104 the outlet valve 16 closed.

According to embodiments, the method may comprise:

- maintaining 106 also the bypass valve 32 closed, while

- drawing liquid 102 into the syringe pump 10 from the milk collecting container 8 via the inlet conduit 12.

According to embodiments, the method may comprise:

- closing 108 the inlet valve 16 prior to completing a liquid drawing stroke of the syringe pump 10,

- maintaining 110 the outlet valve 18 closed, and

- completing 112 the liquid drawing stroke to create a negative pressure in the syringe pump 10 for degassing a liquid in the syringe pump 10.

According to embodiments, the method may comprise:

- opening 114 the inlet valve 16,

- beginning 116 a discharge stroke of the syringe pump 10 prior to opening the outlet valve 18 in order to discharge any gas present in the syringe pump 10 past the inlet valve 16.

According to embodiments, the method may comprise:

- closing 118 the inlet valve 16 during the discharge stroke,

- opening 120 the outlet valve 18 and the bypass valve 32 during the discharge stroke of the syringe pump 10.

According to embodiments, the method may comprise:

- closing 122 the bypass valve 32 during the discharge stroke of the syringe pump 10 to force liquid through the analysis passage 6 and the one-way valve 34.

This invention should not be construed as limited to the embodiments set forth herein. A person skilled in the art will realize that different features of the invention may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims. Although the invention has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. The milk collecting container 8 does not have to be a separate container specific for the use of collecting milk samples - if the milk is collected in a container during milking and it is possible to take a representative sample directly from this container, then this container may serve as the milk collecting container 8. In a freestanding milk analysis apparatus 2, the connection conduits 36 and the three-way valve 38 may be omitted. In such embodiments the milk collecting container 8 may be a fixed container or a removable container. Therefore, it is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.